JP7600618B2 - Photoelectric conversion element and photoelectric conversion module - Google Patents

Description

The present invention relates to a photoelectric conversion element and a photoelectric conversion module.

In recent years, the driving power of electronic circuits has become extremely low, and it has become possible to drive various electronic components such as sensors with very low power (on the order of μW). Furthermore, when using sensors, it is expected that they will be applied to energy harvesting elements as independent power sources that can generate and consume electricity on the spot. Among these, solar cells, a type of photoelectric conversion element, are attracting attention as an element that can generate electricity anywhere there is light, even if the light is very weak.

As a photoelectric conversion element, for example, in order to provide a photoelectric conversion element that allows output extraction with low electrical resistance without deteriorating the photoelectric conversion characteristics, a photoelectric conversion element has been proposed that has a first substrate, a first transparent electrode disposed on the first substrate, a hole blocking layer disposed on the first transparent electrode, an electron transport layer disposed on the hole blocking layer and made of an electron transport semiconductor with a photosensitizing compound adsorbed on the surface, a hole transport layer connected to the electron transport layer and made of a hole transport material, and a second electrode disposed on the hole transport layer, and an output extraction terminal portion for extracting electric power to the outside is formed by a plurality of micropores penetrating the hole blocking layer (see, for example, Patent Document 1).

In order to provide a photoelectric conversion element that has good photoelectric conversion properties even under low illuminance light and has excellent stability over time, a photoelectric conversion element has been proposed that has a first electrode, an electron transport layer having a photosensitizing compound, a hole transport layer, and a second electrode, in which the hole transport layer has a p-type semiconductor material and a basic compound, the ionization potential of the hole transport layer exceeds the ionization potential of the p-type semiconductor material and is less than 1.07 times the ionization potential of the p-type semiconductor material, the ionization potential of the photosensitizing compound exceeds the ionization potential of the hole transport layer, and the acid dissociation constant (pKa) of the basic compound is 6 to 10 (see, for example, Patent Document 2).

The objective of the present invention is to provide a photoelectric conversion element that has excellent output linearity from low to high illuminance.

In order to achieve the above object, the present invention employs the following solutions.
A photoelectric conversion element having a first electrode, a hole blocking layer, a photoelectric conversion layer, a second electrode, and a third electrode,
a photoelectric conversion section including the first electrode, the hole blocking layer, the photoelectric conversion layer, and the second electrode stacked together;
an electrode contact portion where the second electrode is in contact with the third electrode;
a partition portion that partitions the photoelectric conversion portion and the electrode contact portion,
an area (S1) where the second electrode and the third electrode are in contact with each other in the electrode contact portion, and an area (S2) of the photoelectric conversion portion satisfy the following formula (1),
A photoelectric conversion element having an output linearity (Pmax2/Pmax1) of 80% or more and 120% or less, where Pmax1 is the initial maximum output power at 200 lux and Pmax2 is the initial maximum output power at 20,000 lux .
1.0×10 ^-5 ≦ 100× (S1/S2) ≦2.44 ...Formula (1)

The present invention provides a photoelectric conversion element that has excellent output linearity from low to high illuminance.

FIG. 1A is a diagram for explaining an example of a photoelectric conversion element (part 1). FIG. 1B is a diagram for explaining an example of a photoelectric conversion element (part 2). FIG. 1C is a diagram for explaining an example of a photoelectric conversion element (part 3). FIG. 1D is a diagram for explaining an example of a photoelectric conversion element (part 4). FIG. 1E is a diagram for explaining an example of a photoelectric conversion element (part 5). FIG. 2 is a diagram for explaining another example of a photoelectric conversion element. FIG. 3 is a diagram of an example of a through hole in an electrode contact portion. FIG. 4 is a cross-sectional view of another example of a photoelectric conversion element. FIG. 5A is a diagram for explaining an example of a method for manufacturing a photoelectric conversion element (part 1). FIG. 5B is a diagram for explaining an example of a method for manufacturing a photoelectric conversion element (part 2). FIG. 5C is a diagram for explaining an example of a method for manufacturing a photoelectric conversion element (part 3). FIG. 5D is a diagram for explaining an example of a method for manufacturing a photoelectric conversion element (part 4). FIG. 5E is a diagram for explaining an example of a method for manufacturing a photoelectric conversion element (part 5). FIG. 5F is a diagram for explaining an example of a method for manufacturing a photoelectric conversion element (part 6). FIG. 6 is a schematic diagram showing an example in which a mouse is used as an electronic device. FIG. 7 is a schematic diagram showing an example of a mouse equipped with a photoelectric conversion element. FIG. 8 is a schematic diagram showing an example in which a keyboard used in a personal computer is used as the electronic device. FIG. 9 is a schematic diagram showing an example of a keyboard equipped with a photoelectric conversion element. FIG. 10 is a schematic diagram showing an example in which small photoelectric conversion elements are mounted on some of the keys of a keyboard. FIG. 11 is a schematic diagram showing an example in which a sensor is used as an electronic device. FIG. 12 is a schematic diagram showing an example in which a turntable is used as an electronic device. Figure 13 is a schematic diagram showing an example of an electronic device that combines the photoelectric conversion element and/or photoelectric conversion module of the present invention with a device that operates using power generated by photoelectric conversion by the photoelectric conversion element and/or photoelectric conversion module. FIG. 14 is a schematic diagram showing an example in which a power supply IC for the photoelectric conversion element is incorporated between the photoelectric conversion element and the circuit of the device in FIG. FIG. 15 is a schematic diagram showing an example in which a power storage device is incorporated between a power supply IC and a circuit of an apparatus in FIG. FIG. 16 is a schematic diagram showing an example of a power supply module having a photoelectric conversion element and/or a photoelectric conversion module of the present invention and a power supply IC. FIG. 17 is a schematic diagram showing an example of a power supply module in which a power storage device is added to the power supply IC in FIG. FIG. 18A is a diagram showing an example of a photoelectric conversion module (part 1). FIG. 18B is a diagram showing an example of a photoelectric conversion module (part 2). FIG. 19A is a schematic cross-sectional view showing an example of a gap between adjacent photoelectric conversion elements in a photoelectric conversion module. FIG. 19B is a schematic cross-sectional view showing an example of a photoelectric conversion module in which at least one of the electron transport layer and the hole transport layer is not extended between adjacent photoelectric conversion elements. FIG. 19C is a schematic cross-sectional view showing another example of a photoelectric conversion module in which at least one of the electron transport layer and the hole transport layer is not extended between adjacent photoelectric conversion elements. FIG. 19D is a schematic cross-sectional view showing an example of a photoelectric conversion module in which a photoelectric conversion layer does not extend between adjacent photoelectric conversion elements. FIG. 19E is a schematic cross-sectional view showing another example of a photoelectric conversion module in which a photoelectric conversion layer does not extend between adjacent photoelectric conversion elements. FIG. 19F is a schematic cross-sectional view showing another example of a photoelectric conversion module in which a photoelectric conversion layer does not extend between adjacent photoelectric conversion elements. FIG. 19G is a schematic cross-sectional view showing another example of a photoelectric conversion module in which a photoelectric conversion layer does not extend between adjacent photoelectric conversion elements. FIG. 19H is a schematic cross-sectional view showing another example of a photoelectric conversion module in which a photoelectric conversion layer does not extend between adjacent photoelectric conversion elements. FIG. 19I is a schematic cross-sectional view showing another example of a photoelectric conversion module in which a photoelectric conversion layer does not extend between adjacent photoelectric conversion elements. FIG. 19J is a schematic cross-sectional view showing another example of a photoelectric conversion module in which a photoelectric conversion layer does not extend between adjacent photoelectric conversion elements. FIG. 19K is a schematic cross-sectional view showing another example of a photoelectric conversion module in which a photoelectric conversion layer does not extend between adjacent photoelectric conversion elements.

(Photoelectric conversion element)
The photoelectric conversion element of the present invention has at least a first electrode, a hole blocking layer, a photoelectric conversion layer, a second electrode, and a third electrode, and may further have other members such as a substrate, if necessary.

The photoelectric conversion element has a photoelectric conversion portion, an electrode contact portion, and a partition portion.
The photoelectric conversion section is formed by stacking the first electrode, the hole blocking layer, the photoelectric conversion layer, and the second electrode.
At the electrode contact portion, the second electrode is in contact with the third electrode.
The partition separates the photoelectric conversion unit from the electrode contact unit, and prevents a current generated in the photoelectric conversion unit from leaking or shorting at the electrode contact unit.

The photoelectric conversion portion is a portion where photoelectric conversion effectively works.
The electrode contact portion is, for example, a portion where electrical energy generated in the photoelectric conversion portion is extracted to the outside of the element, or a portion where current is extracted to the inside of the element. Therefore, for example, when the photoelectric conversion element is a solar cell, the third electrode is a current extraction electrode, and the electrode contact portion can be called a current extraction portion.
It is not necessary for the second electrode and the third electrode to be in contact with each other over the entire surface of the electrode contact portion.

In the photoelectric conversion element, the area (S1) of the contact between the second electrode and the third electrode in the electrode contact portion and the area (S2) of the photoelectric conversion portion satisfy the following formula (1).
1.0×10 ⁻⁵ ≦ 100×(S1/S2) ...Formula (1)
By doing so, a photoelectric conversion element having excellent output linearity from low illuminance to high illuminance can be obtained. More preferably, the following formula (1-1) is satisfied.
1.0×10 ^-4 ≦ 100× (S1/S2) ... Formula (1-1)
When 100×(S1/S2) is below 1.0×10 ⁻⁵ , the linearity of the output from low illuminance to high illuminance decreases. In particular, the output current decreases due to an increase in the series resistance Rs. This is particularly noticeable on the high illuminance side.
Here, low illuminance refers to 200 lux, and high illuminance refers to 20,000 lux.

If the area (S1) is too large relative to the area (S2), the output per unit area relative to the outer shape of the photoelectric conversion element decreases. In this respect, it is preferable that the area (S1) and the area (S2) satisfy the following formula (1-2).
1.0×10 ^-5 ≦ 100×(S1/S2)≦ 10.0 ... Formula (1-2)
More preferably, it satisfies the following formula (1-3), and even more preferably, it satisfies the following formula (1-4).
1.0×10 ^-5 ≦ 100×(S1/S2)≦ 3.0 ...Formula (1-3)
1.0×10 ^-5 ≦ 100×(S1/S2)≦ 1.0 ... Formula (1-4)

In the photoelectric conversion element, the photoelectric conversion layer extends to the electrode contact section via the partition section, and in the electrode contact section, the second electrode penetrates the photoelectric conversion layer extending to the electrode contact section and contacts the third electrode, which is preferable in terms of reducing leakage current and reducing the risk of short circuiting. If the electrodes come into contact at an unexpected location, a short circuit will occur, so it is preferable to prevent electrical short circuiting except at necessary locations via a semiconductor layer or insulating layer. It is also useful to physically increase the distance between the electrodes to reduce the probability of the electrodes coming into contact when stress is applied, such as by pushing or bending the photoelectric conversion element.

The photoelectric conversion layer includes, for example, an electron transport layer and a hole transport layer.
It is preferable that the width of the partition from the end of the photoelectric conversion part side to the end of the electrode contact part side is 100 times or more the average thickness of the electron transport layer. By doing so, the function of the partition to prevent the current generated in the photoelectric conversion part from leaking at the electrode contact part becomes more prominent. There is no particular limit to the upper limit value, and it can be appropriately selected according to the purpose, but if the partition is wide, the output per unit area relative to the outer shape of the photoelectric conversion element decreases. In that respect, the width of the partition from the end of the photoelectric conversion part side to the end of the electrode contact part side is preferably 1000 times or less the average thickness of the electron transport layer, more preferably 500 times or less, and even more preferably 300 times or less.

Hereinafter, embodiments of the photoelectric conversion element will be described with reference to the drawings.
An example of a photoelectric conversion element will be described with reference to FIGS. 1A to 1E.
Fig. 1A is a cross-sectional view of a photoelectric conversion element. This cross-sectional view is a cross-sectional view of a photoelectric conversion section 51 of the photoelectric conversion element. Therefore, electrode contact sections and partition sections are not shown in Fig. 1A.
A photoelectric conversion section 51 of the photoelectric conversion element has a substrate 1, a first electrode 2, a hole blocking layer 3, a photoelectric conversion layer 4, and a second electrode 5 in this order.
The photoelectric conversion layer 4 has an electron transport layer 14 and a hole transport layer 24 .

Figure 1B is a view of the entire photoelectric conversion element of Figure 1A as seen from the X direction. Here, in Figure 1B, the substrate 1 is omitted to facilitate explanation of the photoelectric conversion section, the electrode contact section, and the partition section. As shown in Figure 1B, the photoelectric conversion element has a photoelectric conversion section 51 that occupies a large area, an electrode contact section 52 formed at the end of the photoelectric conversion element, and a partition section 53 that partitions the photoelectric conversion section 51 and the electrode contact section 52. A first electrode 2 is disposed in the photoelectric conversion section 51. A third electrode 12 is disposed in the electrode contact section 52. The first electrode 2 and the third electrode 12 are on the same plane. In the partition section 53, the first electrode 2 and the third electrode 12 are not in contact with each other.

Figure 1C shows the photoelectric conversion element of Figure 1B rotated 180° vertically. The photoelectric conversion element has a second electrode 5 that spans a photoelectric conversion section 51, a partition section 53, and an electrode contact section 52. The second electrode 5 is recessed inward in the partition section 53. The second electrode 5 is also recessed inward at the location of the electrode contact section 52 where it contacts the third electrode 12.

A cross section taken along line AB in FIGS. 1B and 1C is shown in FIG. 1D.
At the electrode contact portion 52 , the second electrode 5 is in contact with the third electrode 12 .
The photoelectric conversion layer 4 extends to the electrode contact portion 52 via the partition portion 53. In the electrode contact portion 52, the second electrode 5 penetrates the photoelectric conversion layer 4 extending to the electrode contact portion 52 and contacts the third electrode 12.
The line AB is a line passing through the through hole.
The total thickness of the first electrode 2 or the third electrode 12, the hole blocking layer 3, the photoelectric conversion layer 4, and the second electrode 5 is, for example, 1 μm to 3 μm. In contrast, the diameter of the through hole is, for example, 5 μm to 85 μm.
In FIG. 1D, the second electrode 5 of the electrode contact portion 52 is in contact with the substrate 1 through a plurality of through holes. The total area (S11) of the through holes penetrating the photoelectric conversion layer formed to bring the second electrode 5 into contact with the third electrode 12 in the electrode contact portion 52 is not particularly limited and can be appropriately selected according to the purpose, but from the viewpoint of achieving both linearity of the output from low illuminance to high illuminance and the output per unit area relative to the outer shape of the photoelectric conversion element, it is preferable that the following formula (2) is satisfied. More preferably, the following formula (2-1) is satisfied, and even more preferably, the following formula (2-2) is satisfied.
1.0×10 ^-3 ≦ 100× (S11/S2) ≦ 10.0 ... Formula (2)
1.0×10 ^-3 ≦ 100× (S11/S2) ≦ 5.0 ... Formula (2-1)
1.0×10 ^-3 ≦ 100× (S11/S2) ≦ 3.0 ... Formula (2-2)
The width (W) of the partition section 53 from the end on the photoelectric conversion section 51 side to the end on the electrode contact section 52 side is, for example, 100 times or more the average thickness of the electron transport layer 14 .
Here, the area (S1) of contact between the second electrode 5 and the third electrode 12 in the electrode contact portion 52 is the total contact area of the points where the second electrode 5 and the third electrode 12 are in direct contact with each other, that is, the total contact area of the contact points surrounded by the dashed ellipse in Fig. 1D. This contact area can be calculated from, for example, the thickness of the third electrode 12 and the diameter of the through hole.
In addition, contact points that do not contribute to the movement of current from the outside to the inside or from the inside to the outside are not included in the area (S1). For example, in the electrode contact portion 52 of the embodiment in FIG. 3 described later, in a diamond-shaped portion surrounded by individual through holes in a through hole 13 in which a plurality of through holes are integrated, the second electrode 5 and the third electrode 12 may be in contact, but that location does not contribute to the movement of current from the outside to the inside or from the inside to the outside. Therefore, even if the second electrode 5 and the third electrode 12 are in contact with each other in the diamond-shaped portion, the contact area is not included in the area (S1).

On the other hand, a cross section taken along line A'-B' in Fig. 1C is shown in Fig. 1E. Line A'-B' does not pass through the through-hole.
It can be seen that in the electrode contact portion 52 , the photoelectric conversion layer 4 of the photoelectric conversion portion 51 extends through the partition portion 53 in the areas other than the through-holes.

In FIG. 1D, the second electrode 5 of the electrode contact portion 52 is in contact with the substrate 1 via a through hole, but as shown in FIG. 2, the second electrode 5 of the electrode contact portion 52 is in contact with the third electrode 12 but does not necessarily have to be in contact with the substrate 1.
Here, the area (S1) of contact between the second electrode 5 and the third electrode 12 at the electrode contact portion 52 is the total contact area of the points where the second electrode 5 and the third electrode 12 are in direct contact with each other, that is, the total contact area of the contact points surrounded by the dashed ellipse in Fig. 2. This contact area can be calculated from the diameter of the through hole, for example.
Regarding the area (S2) of the photoelectric conversion unit, for example, the area of the second electrode 5 in the photoelectric conversion unit 51 can be set as the area (S2).

In Fig. 1D, the second electrode 5 of the electrode contact portion 52 is in contact with the third electrode 12 via a plurality of independent through holes. However, the through holes penetrating the hole blocking layer 3 and the photoelectric conversion layer 4 in the electrode contact portion 52 do not need to be a plurality of independent through holes, and may be, for example, a through hole 13 in which a plurality of through holes are integrated, as shown in Fig. 3. Fig. 3 is an enlarged view of an example of the electrode contact portion 52 when the photoelectric conversion element is viewed from the second electrode 5 side. The second electrode 5 enters the through hole 13 in which a plurality of through holes are integrated, and a recess following the through hole 13 is generated.
The shape of the through-hole 13 is not particularly limited, and can be appropriately selected from a cube, a cylinder, a square pyramid, a cone shape, etc. A cone shape is preferable, and when the hole is in a cone shape, the second electrode can be formed with a stable film thickness along the inclined surface.

FIG. 4 is a cross-sectional view of another example of a photoelectric conversion element.
The photoelectric conversion element 10 in Fig. 4 is an example in which the electron transport layer 14 in the photoelectric conversion element 10 in Fig. 1A is made of electron transport semiconductor fine particles 14P having a photosensitizing compound adsorbed on the surface thereof. In this case, in the electron transport layer 14, the hole transport material constituting the hole transport layer 24 is present between the electron transport semiconductor fine particles 14P.

<Substrate>
The shape, structure and size of the substrate are not particularly limited and may be appropriately selected depending on the purpose.
The material of the substrate is preferably one having light-transmitting and insulating properties. Examples of such materials include glass, plastic plates, plastic films, plastic membranes, ceramics, and inorganic transparent crystals. Among these, when a firing step is included in forming the electron transport layer, a material having heat resistance to the firing temperature is preferred. In addition, the substrate is preferably one having flexibility.

The average thickness of the substrate is not particularly limited and can be appropriately selected depending on the purpose, for example, 50 μm or more and 5 mm or less.

<First Electrode>
The shape and size of the first electrode are not particularly limited and may be appropriately selected depending on the purpose.

The structure of the first electrode is not particularly limited and can be selected appropriately depending on the purpose. It may be a single-layer structure or a structure in which multiple materials are laminated.

There are no particular limitations on the material of the first electrode as long as it is conductive, and it can be appropriately selected depending on the purpose. Examples include transparent conductive metal oxides, carbon, metals, etc.

Examples of the transparent conductive metal oxide include indium tin oxide (hereinafter referred to as "ITO"), fluorine-doped tin oxide (hereinafter referred to as "FTO"), antimony-doped tin oxide (hereinafter referred to as "ATO"), niobium-doped tin oxide (hereinafter referred to as "NTO"), aluminum-doped zinc oxide (hereinafter referred to as "AZO"), indium zinc oxide, and niobium titanium oxide.
Examples of the carbon include carbon black, carbon nanotubes, graphene, and fullerene.
Examples of the metal include gold, silver, aluminum, nickel, indium, tantalum, and titanium.
These may be used alone or in combination of two or more. Among these, transparent conductive metal oxides having high transparency are preferred, and ITO, FTO, ATO, NTO, and AZO are more preferred.

The average thickness of the first electrode is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 5 nm to 100 μm, more preferably 50 nm to 10 μm. When the material of the first electrode is carbon or metal, the average thickness of the first electrode is preferably set to an average thickness that provides translucency.

The first electrode can be formed by known methods such as sputtering, vapor deposition, spraying, etc.

The first electrode is preferably formed on the substrate, and a commercially available integrated product in which the first electrode is formed on the substrate in advance can be used.
Examples of integrated commercially available products include FTO-coated glass, ITO-coated glass, zinc oxide:aluminum-coated glass, FTO-coated transparent plastic film, ITO-coated transparent plastic film, etc. Other integrated commercially available products include, for example, transparent electrodes in which tin oxide or indium oxide is doped with cations or anions having different valences, or glass substrates provided with metal electrodes having a structure that allows light to pass therethrough, such as mesh-shaped or striped-shaped electrodes.
These may be used alone or in combination of two or more in a mixed or laminated form. In addition, metal lead wires or the like may be used in combination for the purpose of reducing electrical resistance.
Furthermore, electrodes in an integrated commercially available product may be appropriately processed to produce a substrate on which a plurality of first electrodes are formed in order to produce a photoelectric conversion module, which will be described later.

Examples of the material for the metal lead wire include aluminum, copper, silver, gold, platinum, and nickel.
The metal lead wires can be formed on a substrate by, for example, vapor deposition, sputtering, pressure bonding, etc., and then a layer of ITO or FTO is provided thereon, or the metal lead wires can be used in combination by being provided on ITO or FTO.

<Hole blocking layer>
The hole blocking layer is provided, for example, to suppress power reduction caused by recombination (so-called reverse electron transfer) of holes in the electrolyte and electrons on the electrode surface when the electrolyte is in contact with the electrode. The effect of the hole blocking layer is particularly remarkable in solid-state dye-sensitized solar cells. This is because the recombination (reverse electron transfer) rate of holes in the hole transport material and electrons on the electrode surface is faster in solid-state dye-sensitized solar cells using organic hole transport materials, etc., than in wet dye-sensitized solar cells using an electrolyte.

The hole blocking layer is, for example, disposed on the first electrode.

The material for the hole blocking layer is not particularly limited as long as it is transparent to visible light and has electron transport properties, and can be appropriately selected depending on the purpose. Examples of the material include elemental semiconductors such as silicon and germanium, compound semiconductors typified by metal chalcogenides, and compounds having a perovskite structure.
Examples of metal chalcogenides include oxides of titanium, tin, zinc, iron, tungsten, zirconium, hafnium, strontium, indium, cerium, yttrium, lanthanum, vanadium, niobium, and tantalum; sulfides of cadmium, zinc, lead, silver, antimony, and bismuth; selenides of cadmium and lead; telluride of cadmium, etc. Examples of other compound semiconductors include phosphides of zinc, gallium, indium, cadmium, etc.; gallium arsenide, copper-indium-selenide, copper-indium-sulfide, etc.
Examples of compounds having a perovskite structure include strontium titanate, calcium titanate, sodium titanate, barium titanate, and potassium niobate.
Among these, oxide semiconductors are preferable, titanium oxide, niobium oxide, magnesium oxide, aluminum oxide, zinc oxide, tungsten oxide and tin oxide are more preferable, and titanium oxide is further preferable.
These may be used alone or in combination of two or more. They may be a single layer or a laminate. The crystal type of these semiconductors is not particularly limited and may be appropriately selected depending on the purpose, and may be single crystal, polycrystal, or amorphous.

The method for forming the hole blocking layer is not particularly limited and can be appropriately selected depending on the purpose. Examples of the method include a sol-gel method for wet film formation, a hydrolysis method from titanium tetrachloride, and a sputtering method for dry film formation. Among these, the sputtering method is preferred. When the hole blocking layer is formed by the sputtering method, the film density can be sufficiently increased and the loss current can be suppressed.

The average thickness of the hole blocking layer is not particularly limited and can be appropriately selected depending on the purpose, but from the viewpoint of transmittance and suppression of reverse electron transfer, it is preferably 5 nm to 1,000 nm, more preferably 500 nm to 700 nm in wet film formation, and more preferably 5 nm to 30 nm in dry film formation.

<Photoelectric conversion layer>
The photoelectric conversion layer includes an electron transport layer and a hole transport layer, and further includes other members as necessary.

<<Electron Transport Layer>>
The electron transport layer includes an electron transport semiconductor.
The electron transport layer preferably has an electron transport semiconductor having a photosensitizing compound adsorbed on the surface thereof.
The electron transport layer is formed for the purpose of transporting electrons generated in the photosensitizing compound to the first electrode or the hole blocking layer, and therefore, the electron transport layer is preferably disposed adjacent to the first electrode or the hole blocking layer.
The electron transport layer may be a single layer or a multilayer.

As the electron transporting semiconductor, electron transporting semiconductor fine particles are preferably used.
In the case of a multi-layered structure, dispersions of semiconductor fine particles with different particle sizes can be applied in multiple layers, or coating layers of different types of semiconductors, resins, and additive compositions can be applied in multiple layers.
When the thickness of the film is insufficient in one coating, the multi-layer coating is an effective means.
Generally, as the average thickness of the electron transport layer increases, the amount of the photosensitizing material supported per unit projected area also increases, resulting in a higher light capture rate, but the diffusion distance of the injected electrons also increases, resulting in a larger loss due to charge recombination. Therefore, the average thickness of the electron transport layer is preferably 50 nm to 100 μm, more preferably 100 nm to 50 μm, and even more preferably 120 nm to 10 μm.

The electron transport semiconductor is not particularly limited and can be appropriately selected depending on the purpose. Examples of the semiconductor include elemental semiconductors such as silicon and germanium, compound semiconductors such as metal chalcogenides, and compounds having a perovskite structure. These may be used alone or in combination of two or more.

Examples of the metal chalcogenides include oxides of titanium, tin, zinc, iron, tungsten, zirconium, hafnium, strontium, indium, cerium, yttrium, lanthanum, vanadium, niobium, and tantalum; sulfides of cadmium, zinc, lead, silver, antimony, and bismuth; selenides of cadmium and lead, and tellurides of cadmium, etc.
Other compound semiconductors include, for example, phosphides of zinc, gallium, indium, cadmium, and the like, gallium arsenide, copper-indium-selenide, copper-indium-sulfide, and the like.

Examples of compounds having the perovskite structure include strontium titanate, calcium titanate, sodium titanate, barium titanate, and potassium niobate.

Among the electron transporting semiconductors, oxide semiconductors are preferred, and titanium oxide, zinc oxide, tin oxide, and niobium oxide are more preferred.
The crystal type of the electron transporting semiconductor is not particularly limited and can be appropriately selected depending on the purpose, and may be any of single crystal, polycrystalline, and amorphous.

The size of the semiconductor fine particles is not particularly limited and can be appropriately selected depending on the purpose, but the average particle size of the primary particles is preferably 1 nm or more and 100 nm or less, and more preferably 5 nm or more and 50 nm or less.
It is also possible to improve efficiency by mixing or stacking semiconductor particles having a larger average particle size, due to the effect of scattering incident light. In this case, the average particle size of the semiconductor particles is preferably 50 nm or more and 500 nm or less.

The method for producing the electron transport layer is not particularly limited and may be appropriately selected depending on the purpose, and examples of the method include a method for forming a thin film in a vacuum such as sputtering, a wet film-forming method, etc. Among these, in consideration of production costs, etc., the wet film-forming method is preferred, and a method of preparing a paste in which semiconductor fine particles or a sol is dispersed and applying the paste onto the first electrode or onto the hole blocking layer is particularly preferred.
When the wet film-forming method is used, the coating method is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include a dipping method, a spraying method, a wire bar method, a spin coating method, a roller coating method, a blade coating method, a gravure coating method, etc. Examples of the wet printing method include letterpress, offset, gravure, intaglio, rubber plate, screen printing, etc.

When the dispersion of semiconductor particles is prepared by mechanical pulverization or using a mill, it is formed by dispersing at least semiconductor particles alone or a mixture of semiconductor particles and a resin in water or an organic solvent.

The resin is not particularly limited and can be appropriately selected depending on the purpose. Examples of the resin include polymers and copolymers of vinyl compounds such as styrene, vinyl acetate, acrylic acid esters, and methacrylic acid esters, silicone resins, phenoxy resins, polysulfone resins, polyvinyl butyral resins, polyvinyl formal resins, polyester resins, cellulose ester resins, cellulose ether resins, urethane resins, phenolic resins, epoxy resins, polycarbonate resins, polyarylate resins, polyamide resins, and polyimide resins. These may be used alone or in combination of two or more.

Examples of the solvent include water, alcohol solvents, ketone solvents, ester solvents, ether solvents, amide solvents, halogenated hydrocarbon solvents, and hydrocarbon solvents.
Examples of the alcohol solvent include methanol, ethanol, isopropyl alcohol, and α-terpineol.
Examples of the ketone solvent include acetone, methyl ethyl ketone, and methyl isobutyl ketone.
Examples of the ester solvent include ethyl formate, ethyl acetate, and n-butyl acetate.
Examples of the ether solvent include diethyl ether, dimethoxyethane, tetrahydrofuran, dioxolane, and dioxane.
Examples of the amide solvent include N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone.
Examples of the halogenated hydrocarbon solvent include dichloromethane, chloroform, bromoform, methyl iodide, dichloroethane, trichloroethane, trichloroethylene, chlorobenzene, o-dichlorobenzene, fluorobenzene, bromobenzene, iodobenzene, and 1-chloronaphthalene.
Examples of the hydrocarbon solvent include n-pentane, n-hexane, n-octane, 1,5-hexadiene, cyclohexane, methylcyclohexane, cyclohexadiene, benzene, toluene, o-xylene, m-xylene, p-xylene, ethylbenzene, and cumene.
These may be used alone or in combination of two or more.

To the dispersion of the semiconductor particles or the paste of the semiconductor particles obtained by the sol-gel method or the like, an acid, a surfactant, a chelating agent, etc. may be added in order to prevent re-aggregation of the particles.
Examples of the acid include hydrochloric acid, nitric acid, and acetic acid.
The surfactant may, for example, be polyoxyethylene octylphenyl ether.
Examples of the chelating agent include acetylacetone, 2-aminoethanol, and ethylenediamine.
In order to improve film-forming properties, the addition of a thickener is also an effective means.
Examples of the thickener include polyethylene glycol, polyvinyl alcohol, and ethyl cellulose.

The semiconductor fine particles are preferably subjected to baking, microwave irradiation, electron beam irradiation, or laser beam irradiation in order to bring the particles into electronic contact with each other after coating, and to improve the film strength and adhesion to the substrate. These treatments may be used alone or in combination of two or more.
In the case of the baking, the baking temperature is not particularly limited and can be appropriately selected depending on the purpose, but if the temperature is too high, the resistance of the substrate may increase or the substrate may melt, so the baking temperature is preferably 30° C. to 700° C., and more preferably 100° C. to 600° C. The baking time is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 10 minutes to 10 hours.

The microwave irradiation may be performed from the side where the electron transport layer is formed or from the back side. There is no particular restriction on the microwave irradiation time, which may be appropriately selected depending on the purpose, but it is preferable to perform the irradiation for less than one hour.

After the baking, for the purpose of increasing the surface area of the semiconductor fine particles and improving the efficiency of electron injection from the photosensitizing compound to the semiconductor fine particles, a chemical plating process using, for example, an aqueous solution of titanium tetrachloride or a mixed solution of titanium tetrachloride and an organic solvent, or an electrochemical plating process using an aqueous solution of titanium trichloride may be performed.
A film formed by stacking semiconductor particles with diameters of several tens of nanometers by sintering or the like forms a porous structure. This nanoporous structure has a very high surface area, which can be expressed using a roughness factor.
The roughness factor is a value that represents the actual area inside the porous layer relative to the area of the semiconductor particles applied to the substrate. Therefore, the larger the roughness factor, the better. However, in view of the relationship with the film thickness of the electron transport layer, a roughness factor of 20 or more is preferable.

<<Photosensitizing Compound>>
In the present invention, in order to further improve the conversion efficiency, it is preferable to adsorb the photosensitizing compound onto the surface of the electron transporting semiconductor of the electron transporting layer.

The photosensitizing compound is not particularly limited as long as it is a compound that is photoexcited by the excitation light used, and can be appropriately selected according to the purpose. For example, metal complex compounds described in JP-T-7-500630, JP-A-10-233238, JP-A-2000-26487, JP-A-2000-323191, JP-A-2001-59062, etc.; coumarin compounds described in JP-A-10-93118, JP-A-2002-164089, JP-A-2004-95450, J. Phys. Chem. C, 7224, Vol. 111 (2007), etc.; and coumarin compounds described in JP-A-2004-95450, Chem. Commun. , 4887 (2007), etc.; indoline compounds described in JP-A-2003-264010, JP-A-2004-63274, JP-A-2004-115636, JP-A-2004-200068, JP-A-2004-235052, J. Am. Chem. Soc., 12218, Vol. 126 (2004), Chem. Commun., 3036 (2003), Angew. Chem. Int. Ed., 1923, Vol. 47 (2008), etc.; thiophene compounds described in J. Am. Chem. Soc., 14256, Vol. 128 (2006), etc.; cyanine dyes described in JP-A-11-86916, JP-A-11-214730, JP-A-2000-106224, JP-A-2001-76773, JP-A-2003-7359, etc.; mero dyes described in JP-A-11-214731, JP-A-11-238905, JP-A-2001-52766, JP-A-2001-76775, JP-A-2003-7360, etc. Cyanine dyes: 9-arylxanthene compounds described in JP-A-10-92477, JP-A-11-273754, JP-A-11-273755, JP-A-2003-31273, etc.; triarylmethane compounds described in JP-A-10-93118, JP-A-2003-31273, etc.; JP-A-9-199744, JP-A-10-233238, JP-A-11-204821, JP-A-11-265738, J. Phys. Chem., 2342, Vol. 91 (1987), J. Phys. Chem. B, 6272, Vol. 97 (1993), Electroanal. Chem., 31, Vol. 537 (2002), JP-A-2006-032260, J. Porphyrins Phthalocyanines, 230, Vol. 3 (1999), Angew. Chem. Int. Ed., 373, Vol. 46 (2007), Langmuir, 5436, Vol. 24 (2008), etc., can be mentioned as phthalocyanine compounds and porphyrin compounds. Among these, metal complex compounds, coumarin compounds, polyene compounds, indoline compounds, and thiophene compounds are preferred, and compounds represented by the following structural formula (1), the following structural formula (2), and the following structural formula (3), manufactured by Mitsubishi Paper Mills, Ltd., and further compounds including the following general formula (3), are more preferred. These photosensitizing compounds may be used alone or in combination of two or more.

In the general formula (3), X ₁ and X ₂ each independently represent an oxygen atom, a sulfur atom, or a selenium atom.
_R1 represents a methine group which may have a substituent. Specific examples of the substituent include aryl groups such as a phenyl group and a naphthyl group, and heterocycles such as a thienyl group and a furyl group.
_R2 represents an alkyl group, an aryl group, or a heterocyclic group, each of which may have a substituent. Examples of the alkyl group include a methyl group, an ethyl group, a 2-propyl group, and a 2-ethylhexyl group, and examples of the aryl group and the heterocyclic group include those described above.
_R3 represents an acidic group such as a carboxylic acid, a sulfonic acid, a phosphonic acid, a boronic acid, a phenol, etc. _R3 may be one or more.
Z1 and Z2 each independently represent a substituent forming a cyclic structure.
Z1 may be a condensed hydrocarbon compound such as a benzene ring or a naphthalene ring, or a heterocycle such as a thiophene ring or a furan ring, each of which may have a substituent. Specific examples of the substituent include the above-mentioned alkyl groups, and alkoxy groups such as a methoxy group, an ethoxy group, and a 2-isopropoxy group.

Z2 may be any of (A-1) to (A-22) shown below.

Specific examples of photosensitizing compounds containing the above general formula (3) include (B-1) to (B-36) shown below. However, they are not limited to these.

Examples of a method for adsorbing the photosensitizing compound to the electron transporting semiconductor include a method of immersing an electron transporting layer containing a semiconductor material in a solution or a dispersion of the photosensitizing compound, and a method of applying a solution or a dispersion of the photosensitizing compound to the electron transporting layer to adsorb the photosensitizing compound.
Examples of the method for immersing the electron transport layer having the semiconductor material formed thereon in a solution or dispersion of the photosensitizing compound include an immersion method, a dip method, a roller method, and an air knife method.
Examples of a method for applying a solution or a dispersion of a photosensitizing compound to the electron transport layer and causing it to adsorb thereon include a wire bar method, a slide hopper method, an extrusion method, a curtain method, a spin method, and a spray method.
Alternatively, the adsorption may be carried out in a supercritical fluid such as carbon dioxide.

When the photosensitizing compound is adsorbed, a condensing agent may be used in combination.
The condensing agent may be either one that acts catalytically to physically or chemically bind the photosensitizing compound to the surface of the electron transporting semiconductor, or one that acts stoichiometrically to favorably shift the chemical equilibrium.
Furthermore, a thiol or a hydroxy compound may be added as a condensation aid.

Examples of the solvent that dissolves or disperses the photosensitizing compound include water, alcohol solvents, ketone solvents, ester solvents, ether solvents, amide solvents, halogenated hydrocarbon solvents, and hydrocarbon solvents.
Examples of the alcohol solvent include methanol, ethanol, and isopropyl alcohol.
Examples of the ketone solvent include acetone, methyl ethyl ketone, and methyl isobutyl ketone.
Examples of the ester solvent include ethyl formate, ethyl acetate, and n-butyl acetate.
Examples of the ether solvent include diethyl ether, dimethoxyethane, tetrahydrofuran, dioxolane, and dioxane.
Examples of the amide solvent include N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone.
Examples of the halogenated hydrocarbon solvent include dichloromethane, chloroform, bromoform, methyl iodide, dichloroethane, trichloroethane, trichloroethylene, chlorobenzene, o-dichlorobenzene, fluorobenzene, bromobenzene, iodobenzene, and 1-chloronaphthalene.
Examples of the hydrocarbon solvent include n-pentane, n-hexane, n-octane, 1,5-hexadiene, cyclohexane, methylcyclohexane, cyclohexadiene, benzene, toluene, o-xylene, m-xylene, p-xylene, ethylbenzene, and cumene.
These may be used alone or in combination of two or more.

Some types of photosensitizing compounds function more effectively when aggregation between the compounds is suppressed, and therefore an aggregation dissociation agent may be used in combination.
The disaggregating agent is not particularly limited and can be appropriately selected depending on the dye used. Examples of the disaggregating agent include steroid compounds such as cholic acid and chenodeoxycholic acid, long-chain alkyl carboxylic acids, and long-chain alkyl phosphonic acids.
The amount of the disaggregation agent added is preferably 0.01 parts by mass or more and 500 parts by mass or less, and more preferably 0.1 parts by mass or more and 100 parts by mass or less, relative to 1 part by mass of the photosensitizing compound.
The temperature at which the photosensitizing compound or the photosensitizing compound and the disaggregation agent are adsorbed using these is preferably from -50°C to 200°C.
The adsorption may be carried out either by leaving the mixture at rest or by stirring.
The stirring method is not particularly limited and may be appropriately selected depending on the purpose. Examples of the stirring method include a stirrer, a ball mill, a paint conditioner, a sand mill, an attritor, a disperser, and ultrasonic dispersion.
The time required for the adsorption is preferably from 5 seconds to 1,000 hours, more preferably from 10 seconds to 500 hours, and even more preferably from 1 minute to 150 hours.
The adsorption is preferably carried out in a dark place.

<<Hole transport layer>>
Examples of materials constituting the hole transport layer include an electrolyte solution in which a redox pair is dissolved in an organic solvent, a gel electrolyte in which a polymer matrix is impregnated with a liquid in which a redox pair is dissolved in an organic solvent, a molten salt containing a redox pair, a solid electrolyte, an inorganic hole transport material, and an organic hole transport material.
The inorganic hole transport material is not particularly limited and can be appropriately selected depending on the purpose. Examples of the inorganic hole transport material include CuSCN, CuI, CuBr, NiO, V ₂ O ₅ , and graphene oxide.
Among these, organic hole transport materials are preferable. Note that, although the organic hole transport materials are used as examples in the following description, the present invention is not limited thereto.

The organic hole transport material is not particularly limited and can be appropriately selected according to the purpose. For example, oxadiazole compounds shown in JP-B-34-5466, triphenylmethane compounds shown in JP-B-45-555, pyrazoline compounds shown in JP-B-52-4188, hydrazone compounds shown in JP-B-55-42380, oxadiazole compounds shown in JP-A-56-123544, tetraarylbenzidine compounds shown in JP-A-54-58445, stilbene compounds shown in JP-A-58-65440 or JP-A-60-98437, spiro compounds, etc. can be mentioned. These may be used alone or in combination of two or more. Among these, spiro compounds are preferred.

Examples of the spiro compound include compounds represented by the following general formula (4).
In the general formula (4), R ₄ to R ₇ each independently represent a substituted amino group such as a dimethylamino group, a diphenylamino group, or a naphthyl-4-tolylamino group.

The spiro-type compound is not particularly limited and can be appropriately selected depending on the purpose. Examples of the spiro-type compound include, but are not limited to, the following exemplary compounds (D-1) to (D-20). These compounds may be used alone or in combination of two or more.

Spiro compounds have two benzidine skeleton molecules that are twisted and bonded together, forming a nearly spherical electron cloud, and exhibit excellent photoelectric conversion properties due to their good intermolecular hopping conductivity. In addition, they are highly soluble, dissolving in various organic solvents, and being amorphous (amorphous substance without a crystal structure), they are easily densely packed into porous electron transport layers. Furthermore, because they do not have light absorption properties above 450 nm, they can be used to efficiently absorb light in photosensitizing compounds, making them particularly suitable for solid-state dye-sensitized solar cells.

<<Basic Compounds>>
The hole transport layer contains a basic compound.
The basic compound is believed to be present at the interface in the vicinity of the electron transport layer, and is believed to suppress reverse electron transfer from the electron transport layer (that is, electron transfer from the electron transport layer to the hole transport layer).
The basic compound is preferably a basic compound represented by the following general formula (A) or general formula (B), and more preferably a tertiary amine compound represented by the following general formula (1) and general formula (2). When the hole transport layer contains a basic compound represented by the following general formula (A) or general formula (B), it is advantageous in that a high open circuit voltage is obtained and high photoelectric conversion characteristics are obtained. Furthermore, when the hole transport layer contains at least one of the tertiary amine compounds represented by general formula (1) and general formula (2), high photoelectric conversion properties and stability over time can be achieved even under low illuminance light.

(In the formula, R ₁ and R ₂ each independently represent an alkyl group or an aromatic hydrocarbon group, and may be the same or different, or R ₁ and R ₂ may be bonded to each other to represent a heterocyclic group containing a nitrogen atom.)

(In the formula, R ₁ and R ₂ each independently represent an alkyl group or an aromatic hydrocarbon group, and may be the same or different, or R ₁ and R ₂ may be bonded to each other to represent a heterocyclic group containing a nitrogen atom.)

ただし、前記一般式（１）、及び前記一般式（２）中、Ａｒ_１及びＡｒ_２は、置換基を有していてもよいアリール基を表し、前記Ａｒ_１及び前記Ａｒ_２は、同一でも異なっていてもよく、互いに結合してもよい。

In the general formula (1) and the general formula (2), Ar ₁ and Ar ₂ represent an aryl group which may have a substituent, and Ar ₁ and Ar ₂ may be the same or different, and may be bonded to each other.

Specific examples of the basic compounds of the general formula (A) and the general formula (B) are shown below, but the present invention is not limited to these.

Specific examples of the tertiary amine compounds represented by the above general formula (1) and the above general formula (2) include, but are not limited to, the following exemplary compounds C-1 to C-20. These may be used alone or in combination of two or more.

The content of the basic compound in the hole transport layer is preferably 1 part by weight to 50 parts by weight, more preferably 10 parts by weight to 30 parts by weight, based on the total amount of the hole transport material. By setting the content of the basic compound within the preferred range, a high open circuit voltage can be maintained, high output can be obtained, and high stability and durability can be obtained even when used for a long period of time in various environments.

<<<Oxidizing agent>>>
The hole transport layer preferably contains an oxidizing agent, which causes a part of the organic hole transport material to become a radical cation, thereby improving the electrical conductivity and enhancing the durability and stability of the output characteristics.
The organic hole transport material is oxidized by the oxidizing agent, thereby exhibiting good hole conductivity, and also exhibiting good stability over time by suppressing the release of the oxidized state (reduction) caused by the influence of the surrounding environment of the photoelectric conversion layer.

The oxidizing agent is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include tris(4-bromophenyl)aminium hexachloroantimonate, silver hexafluoroantimonate, nitrosonium tetrafluoroborate, silver nitrate, metal complexes, etc. These may be used alone or in combination of two or more. Among these, metal complexes are preferred.
The metal complex may be, for example, a complex composed of a metal cation, a ligand, and an anion.
The metal cation is not particularly limited and can be appropriately selected according to the purpose, and examples thereof include chromium, manganese, zinc, iron, cobalt, nickel, copper, molybdenum, ruthenium, rhodium, palladium, silver, tungsten, rhenium, osmium, iridium, vanadium, gold, platinum, and other cations.Among these, manganese, zinc, iron, cobalt, nickel, copper, ruthenium, silver, and vanadium cations are preferred, and cobalt cations are more preferred.That is, the metal complex is more preferably a cobalt complex.
The ligand is preferably one containing at least one nitrogen-containing 5- and/or 6-membered heterocycle, which may have a substituent. Specific examples include, but are not limited to, the following:

Examples of the anion include hydride ion (H ⁻ ), fluoride ion (F ⁻ ), chloride ion (Cl ⁻ ), bromide ion (Br ⁻ ), iodide ion (I ⁻ ), hydroxide ion (OH ⁻ ), cyanide ion (CN ⁻ ), nitrate ion (NO ₃ ⁻ ), nitrite ion (NO ₂ ⁻ ), hypochlorite ion (ClO ⁻ ), chlorite ion (ClO ₂ ⁻ ), chlorate ion (ClO ₃ ⁻ ), perchlorate ion (ClO ₄ ⁻ ), permanganate ion (MnO ₄ ⁻ ), acetate ion (CH ₃ COO ⁻ ), hydrogen carbonate ion (HCO ₃ ⁻ ), dihydrogen phosphate ion (H ₂ PO ₄ ⁻ ), hydrogen sulfate ion (HSO ₄ ⁻ ), hydrogen sulfide ion (HS ⁻ ), and thiocyanate ion (SCN ⁻ ), tetrafluoroborate ion (BF ₄ ^- ), hexafluorophosphate ion (PF ₆ ^- ), tetracyanoborate ion (B(CN) ₄ ^- ), dicyanoamine ion (N(CN) ₂ ^- ), p-toluenesulfonate ion (TsO ^- ), trifluoromethylsulfonate ion (CF ₃ SO2- ), bis(trifluoromethylsulfonyl)amine ion (N(SO ₂ CF ₃ ) ₂ ^- ), tetrahydroxoaluminate ion ([Al(OH) ₄ ] ^- or [Al(OH) ₄ (H ₂ O) ₂ ] ^- ), dicyanarginate(I) ion ([Ag(CN) ₂ ] ^- ), tetrahydroxochromate(III) ion ([Cr(OH) ₄ ] ^- ), tetrachloroaurate(III) ion ([AuCl ₄ ] ⁻ ), oxide ion (O ₂ − ), sulfide ion (S ₂ ⁻ ), peroxide ion (O ₂ ²⁻ ), sulfate ion (SO ₄ ²⁻ ), sulfite ion (SO ₃ ²⁻ ), thiosulfate ion (S ₂ O ₃ ²⁻ ), carbonate ion (CO ₃ ²⁻ ), chromate ion (CrO ₄ ²⁻ ), dichromate ion (Cr ₂ O ₇ ²⁻ ), monohydrogen phosphate ion (HPO ₄ ²⁻ ), tetrahydroxozincate(II) ion ([ _Zn (OH) ₄ ] ²⁻ ), tetracyanozincate(II) ion ([Zn(CN) ₄ ] ²⁻ ), tetrachlorocuprate(II) ion ([CuCl ₄ ] ²⁻ ), phosphate ion (PO ₄ ³⁻ ), hexacyanoferrate(III) ion ([Fe(CN) ₆ ] ³⁻ ), bis(thiosulfato)argentate(I) ion ([Ag(S ₂ O ₃ ) ₂ ] ³⁻ ), and hexacyanoferrate(II) ion ([Fe(CN) ₆ ] ⁴⁻ ). Of these, tetrafluoroborate ion, hexafluorophosphate ion, tetracyanoborate ion, bis(trifluoromethylsulfonyl)amine ion, and perchlorate ion are preferred.

As the metal complex, a trivalent cobalt complex represented by the following general formula (5) is particularly preferred. When the metal complex is a trivalent cobalt complex, it is advantageous in that it functions excellently as an oxidizing agent.

In the general formula (5), R ₈ to R ₁₀ each independently represent a hydrogen atom, a methyl group, an ethyl group, a tertiary butyl group, or a trifluoromethyl group, and X ⁻ represents any one selected from the above monovalent anions.

Specific examples of the cobalt complex represented by the general formula (5) are described below. However, the present invention is not limited to these. These may be used alone or in combination of two or more.

In addition, a trivalent cobalt complex represented by the following general formula (6) can also be effectively used as the metal complex.

In the general formula (6), R ₁₁ and R ₁₂ each independently represent a hydrogen atom, a methyl group, an ethyl group, a tertiary butyl group, or a trifluoromethyl group, and X ⁻ represents any one selected from the above monovalent anions.

Specific examples of the cobalt complex represented by the general formula (6) are described below. However, the present invention is not limited to these. These may be used alone or in combination of two or more.

The content of the oxidizing agent is preferably 0.5 parts by mass or more and 50 parts by mass or less, and more preferably 5 parts by mass or more and 30 parts by mass or less, relative to 100 parts by mass of the hole transport material. It is not necessary for all of the hole transport material to be oxidized by adding the oxidizing agent, and it is effective if only a portion of the hole transport material is oxidized.

<<<Alkali metal salts>>>
The hole transport layer preferably contains an alkali metal salt as an additive, which is advantageous in that charge transfer becomes smooth and good photoelectric conversion characteristics can be obtained.
The cations of the alkali metal salt are believed to be present at the interface near the electron transport layer, and the anions of the alkali metal salt are believed to be doped into the hole transport layer.

Examples of the alkali metal salt include lithium salts such as lithium chloride, lithium bromide, lithium iodide, lithium perchlorate, lithium bis(trifluoromethanesulfonyl)diimide, lithium diisopropylimide, lithium acetate, lithium tetrafluoroborate, lithium pentafluorophosphate, and lithium tetracyanoborate; sodium salts such as sodium chloride, sodium bromide, sodium iodide, sodium perchlorate, sodium bis(trifluoromethanesulfonyl)diimide, sodium acetate, sodium tetrafluoroborate, sodium pentafluorophosphate, and sodium tetracyanoborate; and potassium salts such as potassium chloride, potassium bromide, potassium iodide, and potassium perchlorate. Among these, lithium bis(trifluoromethanesulfonyl)diimide and lithium diisopropylimide are preferred.

The content of the alkali metal salt is preferably 1 part by mass or more and 50 parts by mass or less, and more preferably 5 parts by mass or more and 30 parts by mass or less, relative to 100 parts by mass of the hole transport material.

The hole transport layer may be a single layer structure made of a single material, or a laminate structure containing multiple compounds. When the hole transport layer has a laminate structure, it is preferable to use a polymer material for the hole transport layer close to the second electrode. The use of a polymer material with excellent film-forming properties is advantageous in that the surface of the porous electron transport layer can be made smoother and the photoelectric conversion characteristics can be improved. In addition, since the polymer material does not easily penetrate into the porous electron transport layer, it has excellent coverage of the surface of the porous electron transport layer, and may be effective in preventing short circuits when providing electrodes.

The polymer material used for the hole transport layer is not particularly limited, and examples thereof include known hole transport polymer materials.
Examples of the hole transporting polymeric material include polythiophene compounds, polyphenylenevinylene compounds, polyfluorene compounds, polyphenylene compounds, polyarylamine compounds, and polythiadiazole compounds.
Examples of the polythiophene compound include poly(3-n-hexylthiophene), poly(3-n-octyloxythiophene), poly(9,9'-dioctyl-fluorene-co-bithiophene), poly(3,3'''-didodecyl-quaterthiophene), poly(3,6-dioctylthieno[3,2-b]thiophene), and poly(2,5-bis(3-decylthiophen-2-yl)thieno[3 ,2-b]thiophene), poly(3,4-didecylthiophene-co-thieno[3,2-b]thiophene), poly(3,6-dioctylthieno[3,2-b]thiophene-co-thieno[3,2-b]thiophene), poly(3,6-dioctylthieno[3,2-b]thiophene-co-thiophene), poly(3,6-dioctylthieno[3,2-b]thiophene-co-bithiophene).
Examples of the polyphenylenevinylene compound include poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene], poly[2-methoxy-5-(3,7-dimethyloctyloxy)-1,4-phenylenevinylene], and poly[(2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene)-co-(4,4'-biphenylenevinylene)].

Examples of the polyfluorene compound include poly(9,9'-didodecylfluorenyl-2,7-diyl), poly[(9,9-dioctyl-2,7-divinylenefluorene)-alt-co-(9,10-anthracene)], poly[(9,9-dioctyl-2,7-divinylenefluorene)-alt-co-(4,4'-biphenylene)], poly[(9,9-dioctyl-2,7-divinylenefluorene)-alt-co-(2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene)], and poly[(9,9-dioctyl-2,7-diyl)-co-(1,4-(2,5-dihexyloxy)benzene)].

Examples of the polyphenylene compound include poly[2,5-dioctyloxy-1,4-phenylene] and poly[2,5-di(2-ethylhexyloxy-1,4-phenylene].
Examples of the polyarylamine compound include poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt-co-(N,N'-diphenyl)-N,N'-di(p-hexylphenyl)-1,4-diaminobenzene], poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt-co-(N,N'-bis(4-octyloxyphenyl)benzidine-N,N'-(1,4-diphenylene)], poly[(N,N'-bis(4-octyloxyphenyl)benzidine-N,N'-(1,4-diphenylene)], Examples of the poly[(N,N'-bis(4-(2-ethylhexyloxy)phenyl)benzidine-N,N'-(1,4-diphenylene)], poly[phenylimino-1,4-phenylenevinylene-2,5-dioctyloxy-1,4-phenylenevinylene-1,4-phenylene], poly[p-tolylimino-1,4-phenylenevinylene-2,5-di(2-ethylhexyloxy)-1,4-phenylenevinylene-1,4-phenylene], poly[4-(2-ethylhexyloxy)phenylimino-1,4-biphenylene], and the like.

Examples of the polythiadiazole compound include poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt-co-(1,4-benzo(2,1',3)thiadiazole], poly(3,4-didecylthiophene-co-(1,4-benzo(2,1',3)thiadiazole), and the like.
Among these, polythiophene compounds and polyarylamine compounds are preferred from the viewpoints of carrier mobility and ionization potential.

Various additives may be added to the hole transport material.
Examples of the additives include metal iodides such as iodine, lithium iodide, sodium iodide, potassium iodide, cesium iodide, calcium iodide, copper iodide, iron iodide, and silver iodide; quaternary ammonium salts such as tetraalkylammonium iodide and pyridinium iodide; metal bromides such as lithium bromide, sodium bromide, potassium bromide, cesium bromide, and calcium bromide; bromides of quaternary ammonium compounds such as tetraalkylammonium bromide and pyridinium bromide; metal chlorides such as copper chloride and silver chloride; metal acetates such as copper acetate, silver acetate, and palladium acetate; metal sulfates such as copper sulfate and zinc sulfate; Examples of the ionic liquids include an anion salt-ferricyanate salt, a metal complex such as a ferrocene-ferricinium ion, sodium polysulfide, an alkylthiol-alkyl disulfide, and other sulfur compounds, viologen dyes, hydroquinone, 1,2-dimethyl-3-n-propylimidazoinium iodide salt, 1-methyl-3-n-hexylimidazolinium iodide salt, 1,2-dimethyl-3-ethylimidazolium trifluoromethanesulfonate salt, 1-methyl-3-butylimidazolium nonafluorobutylsulfonate salt, and 1-methyl-3-ethylimidazolium bis(trifluoromethyl)sulfonylimide salts described in Inorg. Chem. 35 (1996) 1168, basic compounds such as pyridine, 4-t-butylpyridine, benzimidazole, or derivatives thereof, and alkali metal salts.

The average thickness of the hole transport layer is not particularly limited and can be appropriately selected depending on the purpose, but it is preferable that the hole transport layer has a structure in which the hole transport layer penetrates into the pores of the porous electron transport layer, and the thickness on the electron transport layer is preferably 0.01 μm to 20 μm, more preferably 0.1 μm to 10 μm, and particularly preferably 0.2 μm to 2 μm.

The hole transport layer can be formed directly on the electron transport layer containing the photosensitizing compound.
The method for producing the hole transport layer is not particularly limited and may be appropriately selected depending on the purpose, and examples of the method include a method for forming a thin film in a vacuum such as vacuum deposition, a wet film-forming method, etc. Among these, in terms of production costs, etc., the wet film-forming method is particularly preferred, and the method of coating on the electron transport layer is preferred.
When the wet film-forming method is used, the coating method is not particularly limited and can be performed according to a known method, such as a dip method, a spray method, a wire bar method, a spin coating method, a roller coating method, a blade coating method, or a gravure coating method, and as a wet printing method, various methods such as letterpress, offset, gravure, intaglio, rubber plate, and screen printing can be used.

Alternatively, the film may be formed in a supercritical fluid or a subcritical fluid having a temperature and pressure lower than the critical point.
The supercritical fluid is not particularly limited as long as it exists as a non-coagulating high-density fluid in a temperature and pressure region exceeding the limit (critical point) at which gas and liquid can coexist, does not coagulate even when compressed, and is in a state of not less than the critical temperature and not less than the critical pressure, and can be appropriately selected depending on the purpose, although one with a low critical temperature is preferable.
Examples of the supercritical fluid include carbon monoxide, carbon dioxide, ammonia, nitrogen, water, alcohol solvents, hydrocarbon solvents, halogen solvents, and ether solvents.
Examples of the alcohol solvent include methanol, ethanol, and n-butanol.
Examples of the hydrocarbon solvent include ethane, propane, 2,3-dimethylbutane, benzene, and toluene.
Examples of the halogen solvent include methylene chloride and chlorotrifluoromethane.
The ether solvent includes, for example, dimethyl ether.
These may be used alone or in combination of two or more.
Among these, carbon dioxide is particularly preferred because it has a critical pressure of 7.3 MPa and a critical temperature of 31° C., and therefore can easily produce a supercritical state, and is non-flammable and easy to handle.
The subcritical fluid is not particularly limited as long as it exists as a high-pressure liquid in the temperature and pressure range near the critical point, and can be appropriately selected depending on the purpose.
The compounds listed above as examples of supercritical fluids can also be suitably used as the subcritical fluid.
The critical temperature and critical pressure of the supercritical fluid are not particularly limited and can be appropriately selected depending on the purpose. The critical temperature is preferably from -273°C to 300°C, particularly preferably from 0°C to 200°C.
Furthermore, in addition to the supercritical fluid and the subcritical fluid, an organic solvent and an entrainer can be used in combination. By adding the organic solvent and the entrainer, it is possible to more easily adjust the solubility in the supercritical fluid.

The organic solvent is not particularly limited and can be appropriately selected depending on the purpose. Examples of the organic solvent include ketone solvents, ester solvents, ether solvents, amide solvents, halogenated hydrocarbon solvents, and hydrocarbon solvents.
Examples of the ketone solvent include acetone, methyl ethyl ketone, and methyl isobutyl ketone.
Examples of the ester solvent include ethyl formate, ethyl acetate, and n-butyl acetate.
Examples of the ether solvent include diisopropyl ether, dimethoxyethane, tetrahydrofuran, dioxolane, and dioxane.
Examples of the amide solvent include N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone.
Examples of the halogenated hydrocarbon solvent include dichloromethane, chloroform, bromoform, methyl iodide, dichloroethane, trichloroethane, trichloroethylene, chlorobenzene, o-dichlorobenzene, fluorobenzene, bromobenzene, iodobenzene, and 1-chloronaphthalene.
Examples of the hydrocarbon solvent include n-pentane, n-hexane, n-octane, 1,5-hexadiene, cyclohexane, methylcyclohexane, cyclohexadiene, benzene, toluene, o-xylene, m-xylene, p-xylene, ethylbenzene, and cumene.
These may be used alone or in combination of two or more.

In addition, after providing the organic hole transport material on the electron transport layer containing the electron transport material having the photosensitizing compound adsorbed thereon, a press treatment may be performed. It is considered that the press treatment improves the efficiency by making the organic hole transport material adhere more closely to the electron transport layer, which is a porous electrode.
The press treatment is not particularly limited and can be appropriately selected depending on the purpose. Examples of the press treatment include a press molding method using a flat plate such as an IR tablet molder, and a roll press method using a roller or the like.
The pressure of the press treatment is preferably 10 kgf/cm ² or more, and more preferably 30 kgf/cm ² or more.
The time for the press treatment is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 1 hour or less. Heat may be applied during the press treatment.

During the pressing process, a release agent may be placed between the pressing machine and the electrode.
Examples of the release agent include fluororesins such as polytetrafluoroethylene, polychlorotrifluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, perfluoroalkoxy fluoride resin, polyvinylidene fluoride, ethylene-tetrafluoroethylene copolymer, ethylene-chlorotrifluoroethylene copolymer, and polyvinyl fluoride. These may be used alone or in combination of two or more.

After the pressing, and before providing the second electrode, a metal oxide may be provided between the organic hole transport material and the second electrode.
Examples of the metal oxide include molybdenum oxide, tungsten oxide, vanadium oxide, nickel oxide, etc. These may be used alone or in combination of two or more. Among these, molybdenum oxide is preferred.
The method for providing the metal oxide on the hole transport layer is not particularly limited and can be appropriately selected depending on the purpose. Examples of the method include a method for forming a thin film in a vacuum such as sputtering or vacuum deposition, and a wet film formation method.
The wet film-forming method is preferably a method in which a paste in which a powder or sol of a metal oxide is dispersed is prepared and then coated on the hole transport layer.
The coating method when the wet film-forming method is used is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include a dipping method, a spraying method, a wire bar method, a spin coating method, a roller coating method, a blade coating method, a gravure coating method, etc. Examples of the wet printing method include letterpress, offset, gravure, intaglio, rubber plate, screen printing, etc.
The average thickness of the applied metal oxide is preferably from 0.1 nm to 50 nm, and more preferably from 1 nm to 10 nm.

<Second Electrode>
The second electrode can be formed on the hole transport layer or on a metal oxide in the hole transport layer.
The second electrode can usually be the same as the first electrode, and a support is not necessarily required so long as the strength and sealing property are sufficiently maintained.

The material for the second electrode is not particularly limited and can be appropriately selected depending on the purpose. Examples of the material include metals, carbon compounds, conductive metal oxides, and conductive polymers.
Examples of the metal include platinum, gold, silver, copper, and aluminum.
Examples of the carbon compound include graphite, fullerene, carbon nanotube, and graphene.
Examples of the conductive metal oxide include ITO, FTO, and ATO.
Examples of the conductive polymer include polythiophene and polyaniline.
These may be used alone or in combination of two or more.

The second electrode can be formed on the hole transport layer by a suitable method, such as coating, lamination, deposition, CVD, or lamination, depending on the type of material used and the type of the hole transport layer.

In a photoelectric conversion element, it is preferable that at least one of the first electrode and the second electrode is substantially transparent. It is preferable that the first electrode side is transparent and incident light is made incident from the first electrode side. In this case, it is preferable to use a material that reflects light on the second electrode side, and metal, glass on which a conductive oxide is vapor-deposited, plastic, or a thin metal film is preferably used. It is also an effective method to provide an anti-reflection layer on the incident light side.

<Third Electrode>
The shape and size of the third electrode are not particularly limited and may be appropriately selected depending on the purpose.

The third electrode is, for example, fabricated at the same time as the first electrode.
Therefore, the third electrode has the same material, structure, and thickness as the first electrode.

<Sealing part>
It is preferable that the device has a sealing portion that shields at least the photoelectric conversion layer from the external environment.
It is sufficient that the sealing portion is sandwiched between a pair of substrates and at least the electron transport layer and the hole transport layer are shielded from the external environment, and the sealing portion of the photoelectric conversion element may have a gap.

The position of the sealing part is not particularly limited as long as it is disposed at a position that shields at least the electron transport layer and the hole transport layer from the external environment, and can be appropriately selected depending on the purpose. For example, the sealing part may be provided on the entire surfaces so as to cover the electron transport layer, the hole transport layer, and the second electrode, or a substrate may be disposed above the second electrode, and a sealing member may be provided on the outer edge of the substrate and bonded to at least any one of the first substrate, the first electrode, and the hole blocking layer.
The latter configuration, in which a substrate is disposed and a sealing member is provided on the outer edge thereof, can provide a gap inside the photoelectric conversion element or photoelectric conversion module. The gap can control oxygen and humidity, and is effective in improving output and durability.

The sealing material is not particularly limited as long as it prevents the intrusion of water vapor from the outside air, and can be appropriately selected according to the purpose, and examples thereof include low-melting-point frit glass, ultraviolet-curable resins such as epoxy resins and acrylic resins, and thermosetting resins. These may be used alone or in combination of two or more. In addition to the above-mentioned constituent materials, a desiccant may be mixed in order to further prevent the intrusion of water vapor.
It is preferable to use an epoxy resin as the sealing member.
By using an epoxy resin as the sealing member and by having the hole transport layer contain at least one of the tertiary amine compounds represented by the general formula (1) and the general formula (2), the photoelectric conversion element can maintain a high output level before storage even when stored in a high-temperature and high-humidity environment.
Furthermore, the flexibility of the cured product and the adhesive strength to the substrate can be well maintained, so that good mechanical durability can be obtained.

The epoxy resin is not particularly limited as long as it is a resin obtained by curing a monomer or oligomer having an epoxy group in the molecule, and can be appropriately selected according to the purpose, and examples thereof include water-dispersed type, solventless type, solid type, heat-cured type, curing agent mixed type, and ultraviolet cured type. Among these, the heat-cured type and ultraviolet cured type are preferred, and the ultraviolet cured type is more preferred. The ultraviolet cured type may be heated.
Examples of the epoxy resin include bisphenol A type, bisphenol F type, novolac type, cyclic aliphatic type, long chain aliphatic type, glycidyl amine type, glycidyl ether type, glycidyl ester type, etc. These may be used alone or in combination of two or more types.
The epoxy resin may contain a curing agent and various additives, if necessary.
Examples of the curing agent include amine-based, acid anhydride-based, polyamide-based, and other curing agents.
Examples of the amine-based curing agent include aliphatic polyamines such as diethylenetriamine and triethylenetetramine, and aromatic polyamines such as metaphenylenediamine, diaminodiphenylmethane and diaminodiphenylsulfone.
Examples of acid anhydride curing agents include phthalic anhydride, tetrahydrophthalic anhydride and hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, pyromellitic anhydride, HET acid anhydride, and dodecenylsuccinic anhydride.
Examples of other curing agents include imidazoles, polymercaptans, etc. These may be used alone or in combination of two or more.

Examples of the additives include fillers, spacers, polymerization initiators, drying agents (moisture absorbents), hardening accelerators, coupling agents, flexibilizers, colorants, flame retardant assistants, antioxidants, and organic solvents. These may be used alone or in combination of two or more. Among these, fillers, gap agents, hardening accelerators, polymerization initiators, and drying agents (moisture absorbents) are preferred, with fillers and polymerization initiators being particularly preferred.

-Filling material-
The filler is effective in suppressing the intrusion of moisture and oxygen in the external environment, and can also provide effects such as reducing volumetric shrinkage during curing, reducing the amount of gas generated during curing or heating, improving mechanical strength, and controlling thermal conductivity and fluidity, and is therefore extremely effective in maintaining stable output in various environments in the present invention.
The output characteristics and durability of a photoelectric conversion element are not only affected by moisture and oxygen that penetrate into the inside of the photoelectric conversion element from the external environment, but also by gases generated when the sealing member is cured and when heated, which cannot be ignored. In particular, the effect of gases generated when heated has a significant effect on the output characteristics when the element is stored in a high-temperature environment.
In this case, by including a filler, gap agent, or desiccant in the sealing material, these materials themselves can suppress the intrusion of moisture and oxygen, and the amount of sealing material used can be reduced, which has the effect of reducing gas generation. This is effective not only during curing, but also when the photoelectric conversion element is stored in a high-temperature environment.
The filler is not particularly limited and may be any known filler, and preferably used are, for example, crystalline or amorphous inorganic fillers such as silica, talc, alumina, aluminum nitride, silicon nitride, calcium silicate, calcium carbonate, etc. These may be used alone or in combination of two or more.
The average primary particle size of the filler is preferably 0.1 μm to 10 μm, more preferably 1 μm to 5 μm. By making the average primary particle size of the filler 0.1 μm to 10 μm, the effect of suppressing the intrusion of moisture and oxygen can be sufficiently obtained, the viscosity becomes appropriate, and it is also effective in improving the adhesion and defoaming property with the substrate, or in controlling the width of the sealing part and in the workability.
The filler is preferably evenly distributed in the sealing portion. This allows the effect of suppressing the intrusion of moisture and oxygen to be sufficiently obtained. When a gap agent or spacer is used, a layer with low filler density may be formed near the interface. In this case, the effect of suppressing the intrusion of moisture and oxygen can be sufficiently obtained by lengthening the distance of the layer with low filler density in the sealing portion width direction. The density of the filler can be measured, for example, by a scanning electron microscope (SEM).
The content of the filler is preferably 10 parts by mass or more and 90 parts by mass or less, and more preferably 20 parts by mass or more and 70 parts by mass or less, based on the total amount of the sealing member. When the content of the filler is 10 parts by mass or more and 90 parts by mass or less, the effect of suppressing the intrusion of moisture and oxygen is sufficiently obtained, the viscosity is appropriate, and the adhesion and workability are also good.

-Gap agent-
The gap agent is also called a gap control agent or a spacer agent, and can control the gap of the sealing part. For example, when a sealing member is applied onto a first substrate or a first electrode, and a second substrate is placed thereon to perform sealing, the gap of the sealing part is made equal to the size of the gap agent by mixing the gap agent into the epoxy resin, and therefore the gap of the sealing part can be easily controlled.
As the gap agent, any known material can be used as long as it is granular, has a uniform particle size, and has high solvent resistance and heat resistance. It is preferable that the gap agent has a high affinity with the epoxy resin and has a spherical particle shape. Specific examples include glass beads, silica fine particles, and organic resin fine particles. These may be used alone or in combination of two or more types.
The particle size of the gap agent can be selected according to the gap of the sealing portion to be set, but is preferably 1 μm or more and 100 μm or less, and more preferably 5 μm or more and 50 μm or less.
Another method for controlling the seal gap is to provide a spacer.
The spacer may be disposed anywhere on the periphery of the photoelectric conversion layer, for example, on the first substrate, the first electrode, the hole blocking layer, the deletion layer, the second electrode, the second substrate, or a combination thereof.
The spacer may be disposed outside the sealing portion, or may be contained within the sealing portion.
The spacer material is not particularly limited as long as it prevents the intrusion of water vapor from the outside air, and can be appropriately selected depending on the purpose. For example, glass materials, metal materials, metal oxide materials, ultraviolet curing resins such as epoxy resins and acrylic resins, thermosetting resins, etc. can be mentioned. These may be used alone or in combination of two or more kinds.

- Polymerization initiator -
The polymerization initiator is a material added for the purpose of initiating polymerization using heat or light, and examples of the polymerization initiator include a thermal polymerization initiator and a photopolymerization initiator.
The thermal polymerization initiator is a compound that generates active species such as radicals or cations when heated. Specific examples of the thermal polymerization initiator include azo compounds such as 2,2'-azobisbutyronitrile (AIBN) and peroxides such as benzoyl peroxide (BPO).
Examples of the thermal cationic polymerization initiator include benzenesulfonic acid esters and alkylsulfonium salts.

In the case of an epoxy resin, a photocationic polymerization initiator is preferably used as the photopolymerization initiator. When the photocationic polymerization initiator is mixed with the epoxy resin and irradiated with light, the photocationic polymerization initiator decomposes to generate a strong acid, which induces polymerization of the epoxy resin and progresses the curing reaction. The photocationic polymerization initiator has the effects of causing little volumetric shrinkage during curing, not being inhibited by oxygen, and having high storage stability.
Examples of the photocationic polymerization initiator include aromatic diazonium salts, aromatic iodonium salts, aromatic sulfonium salts, methacerone compounds, silanol-aluminum complexes, etc. Photoacid generators that generate an acid when irradiated with light can also be used.
The photoacid generator acts as an acid that initiates cationic polymerization, and examples of the photoacid generator include ionic onium salts such as sulfonium salts and iodonium salts, each of which is composed of a cationic moiety and an anionic moiety. These may be used alone or in combination of two or more kinds.
The content of the polymerization initiator is preferably 0.5 parts by mass or more and 10 parts by mass or less, and more preferably 1 part by mass or more and 5 parts by mass or less, based on the total amount of the sealing member. When the content of the polymerization initiator is 0.5 parts by mass or more and 10 parts by mass or less, curing proceeds appropriately, the amount of remaining uncured material can be reduced, and the generation of an excessive amount of gas can be prevented, which is effective.

-Desiccant-
The desiccant is also called a moisture absorbent, and is a material that has the function of physically or chemically adsorbing or absorbing moisture. By including it in the sealing member, it is effective because it can further increase the moisture resistance and in some cases reduce the effects of the outgassing.
The desiccant is preferably particulate, and examples thereof include inorganic water-absorbing materials such as calcium oxide, barium oxide, magnesium oxide, magnesium sulfate, sodium sulfate, calcium chloride, silica gel, molecular sieves, and zeolite. These may be used alone or in combination of two or more. Among these, zeolite, which has a large moisture absorption capacity, is preferred.

- Hardening accelerator -
The curing accelerator is also called a curing catalyst, and is used for the purpose of accelerating the curing speed, and is mainly used for thermosetting epoxy resins.
Examples of the curing accelerator include tertiary amines or tertiary amine salts such as DBU (1,8-diazabicyclo(5,4,0)-undecene-7) and DBN (1,5-diazabicyclo(4,3,0)-nonene-5), imidazoles such as 1-cyanoethyl-2-ethyl-4-methylimidazole and 2-ethyl-4-methylimidazole, and phosphines or phosphonium salts such as triphenylphosphine and tetraphenylphosphonium tetraphenylborate. These may be used alone or in combination of two or more.

-Coupling agent-
The coupling agent has the effect of increasing molecular bonding strength, and examples thereof include silane coupling agents, such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, N-(2-aminoethyl)3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)3-aminopropylmethyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, vinyltrimethoxysilane, N-(2-(vinylbenzylamino)ethyl)3-aminopropyltrimethoxysilane hydrochloride, and 3-methacryloxypropyltrimethoxysilane. These may be used alone or in combination of two or more.

The sealing member is an epoxy resin composition that is commercially available as a sealing material, a sealing material, or an adhesive, and can be effectively used in the present invention. Among these, there are epoxy resin compositions that have been developed and are commercially available for use in solar cells and organic EL elements, and can be particularly effectively used in the present invention.
Examples of the commercially available products include those under the trade names TB3118, TB3114, TB3124, TB3125F (all manufactured by ThreeBond Co., Ltd.), WorldRock5910, WorldRock5920, WorldRock8723 (all manufactured by Kyoritsu Chemical Industries Co., Ltd.), and WB90US(P) (all manufactured by Moresco).
In addition, epoxy resin compositions disclosed in, for example, Japanese Patent No. 4918975, Japanese Patent No. 5812275, Japanese Patent No. 5835664, Japanese Patent No. 5930248, and Japanese Unexamined Patent Publication No. 2012-136614 can also be used.

In the present invention, a sheet-like sealing material can also be effectively used.
The sheet-like sealing material is a sheet on which an epoxy resin layer is formed in advance, and the sheet is made of glass or a film with high gas barrier properties, and corresponds to the substrate in the present invention. The sheet-like sealing material is attached onto the photoelectric conversion element or the second electrode of the photoelectric conversion module, and then cured, thereby forming the sealing member and the substrate at the same time. Depending on the formation pattern of the epoxy resin layer formed on the sheet, it is also possible to effectively form a structure in which a void is provided inside the photoelectric conversion element.
It is particularly preferable to incorporate oxygen into the voids. By incorporating oxygen, it becomes possible to stably maintain the hole transport function of the hole transport layer for a long period of time, and the durability of the photoelectric conversion element or the photoelectric conversion module can be improved. The oxygen concentration of the voids inside the photoelectric conversion element provided by sealing is preferably 1.0 volume % or more and 21.0 volume % or less, and more preferably 3.0 volume % or more and 15.0 volume % or less, although the effect can be obtained as long as oxygen is contained.
The oxygen concentration in the gap can be controlled by sealing it in a glove box in which the oxygen concentration is set. The oxygen concentration can be set by using a gas cylinder having a specific oxygen concentration or by using a nitrogen gas generator. The oxygen concentration in the glove box is measured using a commercially available oxygen concentration meter or oxygen monitor.
The oxygen concentration in the gap formed by sealing can be measured, for example, by an atmospheric pressure ionization mass spectrometer (API-MS). Specifically, the photoelectric conversion element or the photoelectric conversion module is placed in a chamber filled with an inert gas, the seal is removed in the chamber, and the gas in the chamber is quantitatively analyzed by API-MS to quantify all components in the gas contained in the gap, and the ratio of oxygen to the sum of the components is calculated, thereby obtaining the oxygen concentration.
As the gas other than oxygen, an inert gas such as nitrogen or argon is preferable.
When sealing, it is preferable to control the dew point as well as the oxygen concentration inside the glove box, which is effective in improving the output and durability.
The dew point is defined as the temperature at which condensation begins when a gas containing water vapor is cooled. The dew point is preferably 0° C. or lower, more preferably −20° C. or lower. The lower limit is preferably −50° C. or higher.
A passivation layer may be provided between the second electrode and the sealing member. The passivation layer is not particularly limited and can be appropriately selected depending on the purpose. For example, aluminum oxide, silicon nitride, silicon oxide, etc. are preferable.

The method for forming the sealing member is not particularly limited and can be appropriately selected depending on the purpose. Examples include dispensing, wire bar, spin coating, roller coating, blade coating, gravure coating, letterpress, offset, intaglio, rubber plate, and screen printing.

<Method of Manufacturing Photoelectric Conversion Element>
The method for producing the photoelectric conversion element is not particularly limited and can be appropriately selected depending on the purpose.

An example of a method for manufacturing a photoelectric conversion element will be described with reference to Figures 5A to 5F. Here, a method for manufacturing the photoelectric conversion element shown in Figure 1D will be described, focusing on a method for manufacturing the shape of the end portion of the photoelectric conversion element.
A laminate is prepared in which a portion that will become a partition is provided on a substrate 1, and a first electrode 2, a hole blocking layer 2, and a third electrode 12 are formed (FIG. 5C).

The partitioning portion may be formed by forming a patterned film by protecting the first electrode 2 and the hole blocking layer 3 with a resist or a mask when forming the first electrode 2 and the hole blocking layer 3 .
When the partitions are to be formed later on a laminate plate having the hole blocking layer 3 laminated thereon, the laminate plate can be produced as follows.
First, a laminate having a first electrode precursor 2A formed on a substrate 1 is prepared (FIG. 5A). The material of the first electrode precursor 2A is the same as the material of the first electrode 2.
Next, a precursor 2A of a hole blocking layer is formed on the precursor 2A of the first electrode (FIG. 5B). The material of the precursor 3A of the hole blocking layer is the same as the material of the hole blocking layer 3.
Next, a part of the precursor 2A of the first electrode and a part of the precursor 3A of the hole blocking layer are removed from the substrate 1 side to prepare partitions (FIG. 5C).
The method for forming the partitions is not particularly limited and may be appropriately selected depending on the purpose, and examples thereof include sand blasting, water blasting, polishing, chemical etching, laser processing, etc. Among these, laser processing is preferred.
By removing the precursor 2A of the first electrode and the precursor 3A of the hole blocking layer from the portions that will become the partition parts, the first electrode 2 and the hole blocking layer 3 are formed in the portions that will become the photoelectric conversion parts. In addition, the third electrode 12 is formed in the portions that will become the electrode contact parts.

Next, the electron transport layer 14 and the hole transport layer 24 are formed on all of the locations that will become the photoelectric conversion sections, the locations that will become the partition sections, and the locations that will become the electrode contact sections (FIG. 5D).
Next, a plurality of through holes 13 are formed at the locations that will become the electrode contact portions, extending from the hole transport layer 24 to the surface of the substrate 1 (FIG. 5E). The method for forming the through holes 13 is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include sand blasting, water blasting, polishing, chemical etching, and laser processing. Among these, the laser processing is preferred. This allows fine holes to be formed without using sand, etching, resist, etc., and also allows for clean and highly reproducible processing.
Next, a second electrode 5 is formed on all of the hole transport layer 24 in the areas that are to become the photoelectric conversion sections, the partition sections, and the electrode contact sections, and in the through holes 13 (FIG. 5F).
In this manner, the photoelectric conversion element shown in FIG. 1D is obtained.

<Electronic devices>
The electronic device according to the present invention comprises a photoelectric conversion element and/or photoelectric conversion module according to the present invention, and a device that operates using power generated by photoelectric conversion by the photoelectric conversion element and/or photoelectric conversion module, and further comprises other devices as necessary.

<Power supply module>
The power supply module according to the present invention comprises the photoelectric conversion element and/or photoelectric conversion module of the present invention, and a power supply IC, and further comprises other devices as necessary.
A description will be given of specific embodiments of the photoelectric conversion element and photoelectric conversion module of the present invention, and electronic equipment having a device that operates using the electric power generated by these elements.

FIG. 6 shows an example in which a mouse is used as the electronic device.
As shown in Fig. 6, a photoelectric conversion element, a photoelectric conversion module, a power supply IC, and a power storage device are combined, and the supplied power is connected to the power supply of the mouse's control circuit. This allows the mouse to be operated using the power that is charged in the power storage device when not in use, resulting in a mouse that does not require wiring or battery replacement. In addition, eliminating the need for batteries makes it possible to reduce the weight, which is also an advantage.
FIG. 7 shows a schematic diagram of a mouse equipped with a photoelectric conversion element. The photoelectric conversion element, power supply IC, and power storage device are mounted inside the mouse, but the upper part of the photoelectric conversion element is covered with a transparent housing so that light can hit the photoelectric conversion element. It is also possible to mold the entire housing of the mouse from transparent resin. The arrangement of the photoelectric conversion element is not limited to this, and it is also possible and preferable to arrange the photoelectric conversion element in a position where light is irradiated even when the mouse is covered with a hand.
Another embodiment of the photoelectric conversion element and photoelectric conversion module of the present invention, and electronic equipment including a device that operates using the electric power generated by these will be described.
FIG. 8 shows an example in which a keyboard used in a personal computer is used as the electronic device.
As shown in Fig. 8, a photoelectric conversion element, a power supply IC, and a power storage device are combined, and the supplied power is connected to the power supply of the keyboard's control circuit. This allows the power storage device to be charged when the keyboard is not in use, and the keyboard can be operated with that power, resulting in a keyboard that does not require wiring or battery replacement. In addition, eliminating the need for batteries makes it possible to reduce the keyboard's weight, which is also an advantage.
Fig. 9 shows a schematic diagram of a keyboard with a photoelectric conversion element mounted thereon. The photoelectric conversion element, power supply IC, and power storage device are mounted inside the keyboard, but the upper part of the photoelectric conversion element is covered with a transparent housing so that light can reach the photoelectric conversion element. It is also possible to mold the entire keyboard housing from transparent resin. The arrangement of the photoelectric conversion element is not limited to this.
In the case of a small keyboard in which the space for incorporating a photoelectric conversion element is small, it is possible and effective to embed a small photoelectric conversion element in part of a key, as shown in FIG.
Another embodiment of the photoelectric conversion element and photoelectric conversion module of the present invention, and electronic equipment including a device that operates using the electric power generated by these will be described.
FIG. 11 shows an example in which a sensor is used as the electronic device.
As shown in Fig. 11, a photoelectric conversion element, a power supply IC, and a power storage device are combined, and the supplied power is connected to the power supply of the sensor circuit. This makes it possible to configure a sensor module without the need to connect to an external power supply or replace batteries. This is effective as it can be applied to a variety of sensors for sensing objects such as temperature and humidity, illuminance, human presence, _CO2 , acceleration, UV, noise, geomagnetism, and air pressure. As shown in A in Fig. 11, the sensor module is configured to periodically sense the object to be measured and transmit the read data to a PC, smartphone, etc. via wireless communication.
With the advent of the IoT society, it is expected that the number of sensors will increase rapidly. It is very time-consuming and unrealistic to replace the batteries in these countless sensors one by one. In addition, the fact that the sensors are located in places where it is difficult to replace the batteries, such as on ceilings and walls, also makes the work difficult. The fact that power can be supplied by photoelectric conversion elements is also a great advantage. In addition, the photoelectric conversion element of the present invention can obtain high output even at low illuminance, and has a small dependency on the light incidence angle of the output, so it has the advantage of being highly flexible in installation.
Another embodiment of the photoelectric conversion element and photoelectric conversion module of the present invention, and electronic equipment including a device that operates using the electric power generated by these will be described.
FIG. 12 shows an example in which a turntable is used as the electronic device.
As shown in Fig. 12, a photoelectric conversion element, a power supply IC, and a power storage device are combined, and the supplied power is connected to the power supply of the turntable circuit. This makes it possible to configure a turntable without the need to connect to an external power supply or replace batteries.
Turntables are used, for example, in showcases for displaying products, but the wiring for the power supply is unsightly, and the display items must be removed when replacing the batteries, which is a lot of work. By using the photoelectric conversion element of the present invention, such problems can be effectively eliminated.

<Applications>
The above describes the photoelectric conversion element and photoelectric conversion module of the present invention, and the electronic device and power supply module having a device that operates using the power generated by these elements. However, this is only a small part of the scope of the present invention, and the photoelectric conversion element and photoelectric conversion module of the present invention are not limited to these uses.
The photoelectric conversion element and the photoelectric conversion module can be applied to, for example, a power supply device by combining with a circuit board that controls the generated current.
Examples of devices that use power supply devices include electronic desk calculators, wristwatches, mobile phones, electronic notebooks, and electronic paper.
Furthermore, a power supply device having a photoelectric conversion element can be used as an auxiliary power supply for extending the continuous use time of rechargeable or battery-powered electrical appliances.

The photoelectric conversion element and photoelectric conversion module of the present invention can function as an independent power source, and can operate a device using the power generated by photoelectric conversion. The photoelectric conversion element and photoelectric conversion module of the present invention can generate power by being irradiated with light, so there is no need to connect the electronic device to a power source or replace the battery. Therefore, it is possible to operate the electronic device even in places where there is no power supply equipment, to carry it around on one's body, and to operate the electronic device without replacing the battery even in places where it is difficult to replace the battery. In addition, when dry batteries are used, the electronic device becomes heavy and large in size, which can cause problems in installation on a wall or ceiling or in carrying it around, but the photoelectric conversion element and photoelectric conversion module of the present invention are lightweight and thin, so they have a high degree of freedom in installation and are advantageous in terms of wearing and carrying them around.
In this way, the photoelectric conversion element and photoelectric conversion module of the present invention can be used as a standalone power source and can be combined with various electronic devices, such as display devices such as electronic desk calculators, wristwatches, mobile phones, electronic notebooks, and electronic paper, computer accessories such as mice and keyboards, various sensor devices such as temperature and humidity sensors and human presence sensors, transmitters such as beacons and GPS, auxiliary lights, and remote controls.

The photoelectric conversion element and photoelectric conversion module of the present invention can generate electricity even under light with particularly low illuminance, and can generate electricity indoors and even in dimly lit shaded areas, making them applicable in a wide range of applications. In addition, they are highly safe as they do not leak like dry batteries and cannot be swallowed like button batteries. Furthermore, they can be used as auxiliary power sources to extend the continuous use time of rechargeable or battery-powered electrical appliances. In this way, by combining the photoelectric conversion element and photoelectric conversion module of the present invention with a device that operates on the power generated by the photoelectric conversion, electronic devices can be transformed into ones that are lightweight, easy to use, have a high degree of freedom in installation, do not require replacement, are safe, and are also effective in reducing the environmental impact.

A basic configuration diagram of an electronic device that combines the photoelectric conversion element and/or photoelectric conversion module of the present invention with a device that operates with the electric power generated by the photoelectric conversion is shown in Fig. 13. When the photoelectric conversion element is irradiated with light, it generates electric power and can extract the electric power. The circuit of the device can operate with the electric power.
However, since the output of the photoelectric conversion element changes depending on the surrounding illuminance, the electronic device shown in Fig. 13 may not be able to operate stably. In this case, it is possible and effective to incorporate a power supply IC for the photoelectric conversion element between the photoelectric conversion element and the device circuit in order to supply a stable voltage to the circuit side, as shown in Fig. 14.
However, although a photoelectric conversion element can generate power if it is irradiated with light of sufficient illuminance, if the illuminance is insufficient to generate power, the desired power cannot be obtained, which is also a drawback of the photoelectric conversion element. In this case, as shown in Fig. 15, by mounting a power storage device such as a capacitor between the power supply IC and the device circuit, it becomes possible to charge the power storage device with the surplus power from the photoelectric conversion element, and even if the illuminance is too low or no light hits the photoelectric conversion element, it becomes possible to supply the power stored in the power storage device to the device circuit, enabling stable operation.

In this way, in an electronic device that combines the photoelectric conversion element and/or photoelectric conversion module of the present invention with an equipment circuit, by combining a power supply IC and a power storage device, it is possible to operate even in an environment without a power source, and it is possible to operate stably without the need for battery replacement, thereby making it possible to maximize the benefits of the photoelectric conversion element.
On the other hand, the photoelectric conversion element and/or photoelectric conversion module of the present invention can be used as a power supply module and is useful. For example, as shown in Fig. 16, when the photoelectric conversion element and/or photoelectric conversion module of the present invention is connected to a power supply IC for the photoelectric conversion element, a DC power supply module can be configured that can supply the power generated by the photoelectric conversion of the photoelectric conversion element at a constant voltage level by the power supply IC.
Furthermore, as shown in FIG. 17, by adding a power storage device to the power supply IC, it becomes possible to charge the power generated by the photoelectric conversion element into the power storage device, thereby configuring a power supply module that can supply power even when the illuminance is too low or when the photoelectric conversion element is not exposed to light.
The power supply module of the present invention shown in FIGS. 16 and 17 can be used as a power supply module without the need for battery replacement as with conventional primary batteries.

(Photoelectric conversion module)
The photoelectric conversion module of the present invention includes a plurality of photoelectric conversion elements of the present invention, and further includes other members, etc., as necessary.
In a first photoelectric conversion element and a second photoelectric conversion element that are adjacent to each other among the plurality of photoelectric conversion elements, the third electrode of the first photoelectric conversion element is electrically connected to the first electrode of the second photoelectric conversion element. For example, the third electrode of the first photoelectric conversion element is integrated with the first electrode of the second photoelectric conversion element.
In a photoelectric conversion module, a single substrate usually serves as the substrate for a plurality of photoelectric conversion elements.
The photoelectric conversion module may have a configuration in which a plurality of photoelectric conversion elements are connected in series or in parallel.
The photoelectric conversion module may have a pair of substrates, a photoelectric conversion element arrangement region between the pair of substrates, and the sealing member sandwiched between the pair of substrates.

The other components are not particularly limited and can be selected appropriately depending on the purpose. Examples include a moisture-proof back sheet and a glass plate.

Here, an example of electrical connection between adjacent photoelectric conversion elements in a photoelectric conversion module will be described with reference to FIGS. 18A and 18B. FIG.
18A is a view of the photoelectric conversion module 100 as viewed from the substrate side. For ease of explanation, the substrate is omitted and only the first electrode 2 is shown.
Fig. 18B is a diagram of the photoelectric conversion module 100 as viewed from the side of the second electrode 5. Fig. 18B is a diagram of the photoelectric conversion module 100 of Fig. 18A rotated 180° in the up-down direction.
The photoelectric conversion module 100 is composed of three photoelectric conversion elements (a first photoelectric conversion element 10A, a second photoelectric conversion element 10B, and a third photoelectric conversion element 10C).
The first photoelectric conversion element 10A has a photoelectric conversion portion 51A, an electrode contact portion 52A, and a partition portion 53A.
The second photoelectric conversion element 10B has a photoelectric conversion portion 51B, an electrode contact portion 52B, and a partition portion 53B.
The third photoelectric conversion element 10C has a photoelectric conversion portion 51C.
The third electrode 12 of the electrode contact portion 52A of the first photoelectric conversion element 10A is integrated with the first electrode 2 of the second photoelectric conversion element 10B.
The third electrode 12 of the electrode contact portion 52B of the second photoelectric conversion element 10B is integrated with the first electrode 2 of the third photoelectric conversion element 10C.
In the first photoelectric conversion element 10A, the second electrode 5 spans the photoelectric conversion portion 51A, the partition portion 53A, and the electrode contact portion 52A.
In the second photoelectric conversion element 10B, the second electrode 5 spans a photoelectric conversion portion 51B, a partition portion 53B, and an electrode contact portion 52B.
The first electrode 2 and the third electrode 12 of these three photoelectric conversion elements can be fabricated, for example, by patterning the transparent conductive layer of a single substrate on which a transparent conductive layer is formed, by photolithography. They can also be fabricated by sandblasting, water blasting, polishing, chemical etching, laser processing, and the like. Among these, the laser processing is preferred. By doing so, the third electrode 12 of the electrode contact portion 52A of the first photoelectric conversion element 10A and the first electrode 2 of the second photoelectric conversion element 10B can be integrated.

In addition, the photoelectric conversion layer in the photoelectric conversion module may be extended between adjacent photoelectric conversion elements and integrated together, but it is preferable that only one of the electron transport layer and the hole transport layer is extended and integrated together, and it is more preferable that the photoelectric conversion layer is not extended.
When the photoelectric conversion layer, the electron transport layer, or the hole transport layer is extended and integrated, the minimum distance between adjacent photoelectric conversion elements is preferably 10 μm or more, more preferably 30 μm or more, and even more preferably 100 μm or more. Here, the minimum distance between adjacent photoelectric conversion elements is the shorter of the distance between the first electrodes or the distance between the second electrodes of each adjacent photoelectric conversion element.
When the photoelectric conversion layer is not extended, the minimum distance between adjacent photoelectric conversion elements is not particularly limited and can be any distance.
In the above preferred range, the electrical resistance between adjacent photoelectric conversion elements is sufficiently high, so that the leakage current flowing between adjacent photoelectric conversion elements can be suppressed, and high photoelectric conversion characteristics can be obtained. Suppressing the leakage current is advantageous for improving the photoelectric conversion characteristics, particularly at low illuminance.

Here, FIG. 19A is a schematic cross-sectional view showing an example of a gap between adjacent photoelectric conversion elements in a photoelectric conversion module.
19B and 19C are schematic cross-sectional views showing an example of a photoelectric conversion module in which at least one of the electron transport layer and the hole transport layer is not extended between adjacent photoelectric conversion elements.
19D to 19K are schematic cross-sectional views showing an example of a photoelectric conversion module in which a photoelectric conversion layer does not extend between adjacent photoelectric conversion elements.

The present invention will be described below with reference to examples and comparative examples. Note that the present invention is not limited to the examples exemplified here.

(Examples 1 to 14)
<Fabrication of photoelectric conversion element>
First, an ITO conductive film as a first electrode was formed by sputtering on a glass substrate as a first substrate. On the ITO-coated glass on which indium-doped tin oxide (ITO) and niobium-doped tin oxide (NTO) were successively sputtered, a dense layer made of titanium oxide was formed as a hole blocking layer by reactive sputtering with oxygen gas. (ITO conductive film average thickness: 250 nm)
Next, the ITO conductive film and the hole blocking layer were partially impact peeled off by laser irradiation, at the positions that were to become the partitions.
The laser device used was a laser patterning device manufactured by Seishin Shoji Co., Ltd., with an oscillator being a THG (Third Harmonic Generation) oscillator, an output of 9.0 μJ, and a wavelength of 355 nm. By controlling the processing frequency, processing speed, and processing pitch of the laser patterning device, the processing pattern can be set arbitrarily. The length, major axis, and minor axis of the partitioned portion were processed as shown in Tables 2-1 and 2-2.
Next, 3 g of titanium oxide (trade name: P90, manufactured by Nippon Aerosil Co., Ltd.), 0.2 g of acetylacetone, and 0.3 g of polyoxyethylene octylphenyl ether (manufactured by Wako Pure Chemical Industries, Ltd.) as a surfactant were subjected to a bead mill treatment together with 5.5 g of water and 1.0 g of ethanol for 12 hours to prepare a titanium oxide dispersion. 1.2 g of polyethylene glycol (trade name: polyethylene glycol 20,000, manufactured by Wako Pure Chemical Industries, Ltd.) was added to the prepared titanium oxide dispersion to prepare a paste. The prepared paste was applied on the hole blocking layer (average thickness: 1.5 μm), dried at 50 ° C., and then baked in air at 500 ° C. for 30 minutes to form a porous electron transport layer.
The glass substrate on which the electron transport layer was formed was immersed in an acetonitrile/t-butanol (volume ratio 1:1) solution containing 0.2 mM of a photosensitizing compound represented by the following structural formula (A) (product name: DN455, manufactured by Chemiclea Co., Ltd.) and 0.4 mM of chenodeoxycholic acid (CDCA, manufactured by Tokyo Chemical Industry Co., Ltd.), and allowed to stand in a dark place for 1 hour to allow the photosensitizing compound to be adsorbed onto the surface of the electron transport layer.

"Ph" represents a phenyl group.

Next, 37.0 mg of lithium bis(trifluoromethanesulfonyl)imide (trade name: LiTFSI, manufactured by Tokyo Chemical Industry Co., Ltd.) as an additive and 37.5 mg of the basic compound represented by C-1 were added and dissolved in 1 mL of a chlorobenzene solution containing 246.5 mg of the hole transport material represented by D-7 (manufactured by Merck Ltd.) to prepare a hole transport layer coating solution.
Next, the hole transport layer coating solution was spin-coated on the electron transport layer having the photosensitizing compound adsorbed thereon to form a hole transport layer (average thickness: 600 nm).
Next, in order to form electrode contacts, a plurality of through holes were formed from the hole transport layer to the surface of the ITO conductive film or to the surface of the substrate by laser irradiation.
In Tables 2-1 and 2-2, the notation "up to the ITO conductive film" for the through hole refers to the case where the through hole reaches the substrate surface, and the notation "up to the hole blocking layer" for the case where the through hole reaches the surface of the ITO conductive film.
The laser device used was a laser patterning device manufactured by Seishin Shoji Co., Ltd., and the dot diameter, processing pitch, and processing distance were as shown in Tables 2-1 and 2-2.
When the dot diameter is 0.05 mm and the pitch is 0.045 mm, the dots overlap, resulting in a through-hole shape as shown in Fig. 3. When the dot diameter is 0.05 mm and the pitch is 0.06 mm, the dots do not overlap and multiple circular through-holes are formed.
In Examples 1 and 2, the electron transport layer and the hole transport layer were impact peeled off and removed from the third electrode and the partitioning portion by laser irradiation.
Thereafter, silver was vacuum-deposited on the hole transport layer to form a second electrode (average thickness: 100 nm), thereby completing a photoelectric conversion element.
After forming the second electrode, an epoxy resin (ultraviolet-curable, product name: WorldRock No. 5910, manufactured by Kyoritsu Chemical Industries Co., Ltd.) was applied as a sealing material using a screen printer (manufactured by Micro-Tec Co., Ltd.) The widthwise structure can be adjusted by the printing pattern design of a screen printing plate (manufactured by Sonocom Co., Ltd.).
Next, nitrogen gas was introduced into a glove box, and the device was moved therein. A cover glass serving as a second substrate was then placed on top of the sealing member. The sealing member was then cured by ultraviolet light irradiation to seal the power generation region, thereby producing the photoelectric conversion elements of Examples 1 to 14.
The power generation characteristics of the obtained photoelectric conversion elements of Examples 1 to 14 are shown in Tables 2-1 and 2-2.
The through-hole area S11 and the contact area S1 were observed and measured using a scanning electron microscope (SEM) (manufactured by Hitachi High-Technologies Corporation).

<Initial maximum output power (Pmax1) and linearity (Pmax2/Pmax1)>
For each of the produced photoelectric conversion elements, the IV characteristics were evaluated under irradiation of a white LED adjusted to 200 lx using a solar cell evaluation system (DC voltage/current source/monitor, 6241A, manufactured by ADC Corporation), and the initial maximum output power Pmax1 (μW/cm ² ) was calculated.
Next, under irradiation of a white LED adjusted to 20,000 lx, the IV characteristics were evaluated using a solar cell evaluation system (DC voltage/current source/monitor, 6241A, manufactured by ADC Corporation) to determine the initial maximum output power Pmax2 (μW/cm ² ).
The "linearity" (Pmax2/Pmax1) for 100 times the illuminance was obtained by dividing the obtained Pmax2 by the initial value Pmax1. It should be noted that if (Pmax2/Pmax1) is between 80 and 120 , it can be said that there is linearity.

表２－１、表２－２、表３－１、表３－２、及び表４において、「Ｅ」は１０のべき乗を表す。即ち、「Ｅ－０１」は「０．１」を表す。
表２－１、表２－２、表３－１、表３－２、及び表４中、「光電変換層が延在」の項目の「〇」は、区画部を介して電極接触部に光電変換層が延在しており、電極接触部において、第２の電極が電極接触部に延在した光電変換層を貫通して第３の電極と接触していることを表し、「×」は、電極接触部に光電変換層が延在していないことを表す。

In Tables 2-1, 2-2, 3-1, 3-2, and 4, "E" represents a power of 10. That is, "E-01" represents "0.1 . "
In Tables 2-1, 2-2, 3-1, 3-2, and 4, in the item "Photoelectric conversion layer extends" an "O" indicates that the photoelectric conversion layer extends to the electrode contact portion via the partition portion, and that at the electrode contact portion, the second electrode penetrates the photoelectric conversion layer extending to the electrode contact portion and contacts the third electrode, and an "X" indicates that the photoelectric conversion layer does not extend to the electrode contact portion.

(Examples 15 to 23)
18A and 18B, the ITO conductive film, which is the first electrode, was laser-etched by a laser device to form a substrate with eight cells connected in series. After the hole transport layer was formed, through holes for connecting the photoelectric conversion elements in series were formed by laser processing.
At this time, as shown in Fig. 19C, the porous titanium oxide layer was also laser etched at the same time as the ITO conductive film. The average distance between adjacent ITO conductive films was processed to be 30 µm.
The laser device used was a laser patterning device manufactured by Seishin Shoji Co., Ltd., and the dot diameter, processing pitch, and processing distance were as shown in Tables 3-1 and 3-2.
Thereafter, a photoelectric conversion module was produced in the same manner as in Examples 4 to 13, except that a second electrode (average thickness: 100 nm) was formed by vacuum deposition of silver using a mask patterned to form 8 cells in series on the hole transport layer. At this time, the average distance between adjacent silver electrodes was set to 200 μm.
(Pmax2/Pmax1) was determined in the same manner as in Example 1. The results are shown in Tables 3-1 and 3-2.

(Example 24)
As illustrated in FIG. 19A, a photoelectric conversion module was produced in the same manner as in Example 20, except that the porous titanium oxide layer was not laser etched and the photoelectric conversion layer extended between adjacent photoelectric conversion elements.
(Pmax2/Pmax1) was determined in the same manner as in Example 1. The results are shown in Table 3-2.

(Example 25)
As illustrated in FIG. 19I , a photoelectric conversion module was produced in the same manner as in Example 20, except that the porous titanium oxide layer was laser etched simultaneously with the ITO conductive film, and after the hole transport layer was formed, the hole transport layer was laser etched so that the average distance between adjacent ITO conductive films was 30 μm.
(Pmax2/Pmax1) was determined in the same manner as in Example 1. The results are shown in Table 3-2.

(Comparative Examples 1 to 2)
A photoelectric conversion element was fabricated in the same manner as in Example 1, except that the dot diameter, processing pitch, and processing distance were as shown in Table 4, and the third electrode area was as shown in Table 4.

For example, aspects of the present invention are as follows.
<1> A photoelectric conversion element having a first electrode, a hole blocking layer, a photoelectric conversion layer, a second electrode, and a third electrode,
a photoelectric conversion section including the first electrode, the hole blocking layer, the photoelectric conversion layer, and the second electrode stacked together;
an electrode contact portion where the second electrode is in contact with the third electrode;
a partition portion that partitions the photoelectric conversion portion and the electrode contact portion,
This photoelectric conversion element is characterized in that the area (S1) of the contact area between the second electrode and the third electrode in the electrode contact portion and the area (S2) of the photoelectric conversion portion satisfy the following formula (1).
1.0×10 ⁻⁵ ≦ 100×(S1/S2) ...Formula (1)
<2> The photoelectric conversion element according to <1>, wherein the area (S1) and the area (S2) satisfy the following formula (1-1):
1.0×10 ^-4 ≦ 100× (S1/S2) ... Formula (1-1)
<3> The photoelectric conversion layer extends to the electrode contact portion via the partition portion,
This is a photoelectric conversion element described in any one of <1> to <2>, wherein, in the electrode contact portion, the second electrode penetrates the photoelectric conversion layer extending to the electrode contact portion and contacts the third electrode.
<4> The photoelectric conversion layer has an electron transport layer and a hole transport layer,
The photoelectric conversion element according to any one of <1> to <3>, wherein the width of the partition from the end of the photoelectric conversion section on the side of the electrode contact section to the end of the partition section on the side of the electrode contact section is 100 times or more the average thickness of the electron transport layer.
<5> A photoelectric conversion module having a plurality of photoelectric conversion elements according to any one of <1> to <4>,
This photoelectric conversion module is characterized in that, in a first photoelectric conversion element and a second photoelectric conversion element adjacent to each other among a plurality of photoelectric conversion elements, the third electrode of the first photoelectric conversion element is electrically connected to the first electrode of the second photoelectric conversion element.
<6> The photoelectric conversion module according to <5>, wherein the third electrode of the first photoelectric conversion element is integrated with the first electrode of the second photoelectric conversion element.
<7> The photoelectric conversion module according to any one of <5> and <6>, wherein at least one of the electron transport layer and the hole transport layer is not extended between the photoelectric conversion elements adjacent to each other.
<8> The photoelectric conversion module according to any one of <5> and <6>, wherein the photoelectric conversion layer does not extend between the photoelectric conversion elements adjacent to each other.

The photoelectric conversion element described in any one of <1> to <4> and the photoelectric conversion module described in any one of <5> to <8> can solve the above-mentioned problems in the past and achieve the object of the present invention.

REFERENCE SIGNS LIST 1 Substrate 2 First electrode 3 Hole blocking layer 4 Photoelectric conversion layer 5 Second electrode 10 Photoelectric conversion element 12 Third electrode 13 Through hole 14 Electron transport layer 24 Hole transport layer 51 Photoelectric conversion section 52 Electrode contact section 53 Partition section 100 Photoelectric conversion module

JP 2018-98226 A JP 2019-176136 A

Claims (8)

A photoelectric conversion element having a first electrode, a hole blocking layer, a photoelectric conversion layer, a second electrode, and a third electrode,
a photoelectric conversion section including the first electrode, the hole blocking layer, the photoelectric conversion layer, and the second electrode stacked together;
an electrode contact portion where the second electrode is in contact with the third electrode;
a partition portion that partitions the photoelectric conversion portion and the electrode contact portion,
an area (S1) where the second electrode and the third electrode are in contact with each other in the electrode contact portion, and an area (S2) of the photoelectric conversion portion satisfy the following formula (1),
A photoelectric conversion element, characterized in that when an initial maximum output power at 200 lux is Pmax1 and an initial maximum output power at 20,000 lux is Pmax2, the output linearity (Pmax2/Pmax1) is 80 or more and 120 or less .
1.0×10 ⁻⁵ ≦ 100×(S1/S2)≦2.44 ...Formula (1) The photoelectric conversion element according to claim 1, characterized in that the second electrode contacts the third electrode through a plurality of independent through holes in the electrode contact portion. The photoelectric conversion element according to any one of claims 1 to 2, wherein Pmax1 is 6 or more and Pmax2 is 480.38 or more. the photoelectric conversion layer has an electron transport layer and a hole transport layer,
4. The photoelectric conversion element according to claim 1, wherein the width of the partition from an end of the partition on the photoelectric conversion section side to an end of the partition on the electrode contact section side is 100 times or more the average thickness of the electron transport layer. A photoelectric conversion module having a plurality of photoelectric conversion elements according to any one of claims 1 to 4,
A photoelectric conversion module characterized in that, in a first photoelectric conversion element and a second photoelectric conversion element adjacent to each other among a plurality of photoelectric conversion elements, the third electrode of the first photoelectric conversion element is electrically connected to the first electrode of the second photoelectric conversion element. The photoelectric conversion module according to claim 5, wherein the third electrode of the first photoelectric conversion element is integrated with the first electrode of the second photoelectric conversion element. The photoelectric conversion module according to any one of claims 5 to 6, wherein at least one of the electron transport layer and the hole transport layer is not extended between the adjacent photoelectric conversion elements. The photoelectric conversion module according to any one of claims 5 to 6, wherein the photoelectric conversion layer does not extend between the adjacent photoelectric conversion elements.