JP6913310B2 - Semiconductor devices, solar cells, and solar cell modules - Google Patents

Description

The present invention relates to semiconductor devices, solar cells, and solar cell modules.

The performance of semiconductor devices such as field effect transistors, electroluminescent devices (LEDs), and photoelectric conversion elements is greatly affected by the characteristics of the semiconductor layer. For this reason, improvement of the semiconductor layer has become a major target in research for manufacturing high-performance semiconductor devices. For example, Non-Patent Document 1 discloses a solar cell using a perovskite semiconductor as an active layer. In particular, Non-Patent Document 1 describes that hydroiodic acid, which is a raw material for producing methylamine iodide, is added to a perovskite coating solution obtained from lead iodide and methylamine iodide. ing. According to Non-Patent Document 1, since the solubility of perovskite is improved by adding hydroiodic acid, it is possible to prevent lead iodide from being precipitated during the coating film formation of the perovskite semiconductor layer.

Heo et al. Energy and Environmental Science, 2015, 8, 1602-1608.

In order to further improve the performance of semiconductor devices, it is required to further devise the semiconductor layer.

An object of the present invention is to improve the performance of a semiconductor device.

The present inventors have found that the performance of a semiconductor device having a perovskite semiconductor layer is improved by adding an additive to the perovskite semiconductor layer, and completed the present invention based on this finding.

That is, the gist of the present invention lies below.
[1] A semiconductor device having a pair of electrodes and a semiconductor layer arranged between the pair of electrodes, wherein the semiconductor layer contains a monovalent cation, a divalent cation, and a divalent cation containing an additive. It is a perovskite semiconductor layer composed of a monovalent anion, and the additive has a pKa value lower than the pKa value of the monovalent cation, and the pKa value is 0.99 or more and 4.17 or less (however, however). A semiconductor device comprising a compound having a pKa value of 3.09).
[2] The semiconductor device according to [1], wherein the compound is a compound having a carboxyl group, a sulfonic acid group, a phosphoric acid group or an anhydrous carboxylic acid group.
[3] The semiconductor device according to any one of [1] and [2], wherein the compound has a boiling point of 100 ° C. or higher.
[4] The semiconductor device according to any one of [1] to [3], wherein the compound has a melting point of 100 ° C. or higher.
[5] The semiconductor device according to any one of [1] to [4], which is a photoelectric conversion element.
[6] A solar cell including the semiconductor device according to [5].
[7] A solar cell module including the solar cell according to [6].

The performance of the semiconductor device can be improved.

It is sectional drawing which shows typically the electric field effect transistor element which concerns on one Embodiment. It is sectional drawing which shows typically the electroluminescent element which concerns on one Embodiment. It is sectional drawing which shows typically the photoelectric conversion element as one Embodiment. It is sectional drawing which shows typically the solar cell as one Embodiment. It is sectional drawing which shows typically the solar cell module as one Embodiment.

Hereinafter, embodiments of the present invention will be described in detail. The description of the constituent elements described below is an example (representative example) of the embodiment of the present invention, and the present invention is not limited to these contents as long as the gist thereof is not exceeded.

<1. Semiconductor device ＞
The semiconductor device according to the present invention has a pair of electrodes and a perovskite semiconductor layer arranged between the pair of electrodes. In addition, the perovskite semiconductor layer contains a specific additive. Hereinafter, the perovskite semiconductor layer may be simply referred to as a semiconductor layer.

As used herein, the term "semiconductor device" refers to an electronic device including a semiconductor layer containing a semiconductor compound. An electronic device is a device that has two or more electrodes and controls the current or generated voltage flowing between the electrodes by electricity, light, magnetism, chemical substances, etc., or the voltage applied between the electrodes or It refers to a device that generates light, electric field, magnetic field, etc. by electric current. Specific examples include an element that controls a current or a current by applying a voltage or a current, an element that controls a voltage or a current by applying a magnetic field, an element that controls a voltage or a current by acting a chemical substance, and the like. Specific examples of control include rectification, switching, amplification, oscillation, and the like.

In addition, in this specification, "semiconductor" is defined by the magnitude of carrier mobility in a solid state. As is well known, carrier mobility is an index showing how quickly (or many) charges (electrons or holes) can be transferred. Specifically, the "semiconductor" in the present specification preferably has a carrier mobility at room temperature of 1.0 x ^10-6 cm ² / V · s or more, and more preferably 1.0 x ^10-5 cm ² / V · s or more. More preferably, it is 5.0 x ^10-5 cm ² / V · s or more, and particularly preferably 1.0 × 10 ^-4 cm ² / V · s or more. The carrier mobility can be measured, for example, by measuring the IV characteristics of the field-effect transistor, the time-of-flight method, or the like.

Examples of semiconductor devices include resistors, rectifiers (diodes), switching elements (transistors, thyristors), amplification elements (transistors), memory elements, chemical sensors, etc., or devices obtained by combining or integrating these elements. Can be mentioned. Further, a further example of the semiconductor device is an optical element, and the optical element is a photodiode or phototransistor that generates a photocurrent, an electroluminescent element that emits light by applying an electric field, or a photoelectric conversion that generates an electromotive force by light. Elements, solar cells, etc. are included.

More specific examples of semiconductor devices include S.I. M. Examples include those described by Sze, Physics of Semiconductor Devices, 2nd Edition (Wiley Interscience 1981). Among them, preferable examples of the semiconductor device according to one embodiment include a field effect transistor element (FET), an electroluminescent element (LED), a photoelectric conversion element, or a solar cell.

The type of electrode is not particularly limited. Depending on the type of semiconductor device, electrodes can be made using suitable materials. Specific examples of electrodes will be described later with respect to some semiconductor devices.

The pelops-skite semiconductor layer is a layer having semiconductor characteristics and contains a pelops-skite semiconductor compound. The perovskite semiconductor compound refers to a semiconductor compound having a perovskite structure. The perovskite semiconductor compound is not particularly limited, but can be selected from, for example, those listed in Galasso et al. Structure and Properties of Inorganic Solids, Chapter 7 --Perovskite type and related structures. For example, examples of the perovskite semiconductor compound include _{those represented by the general formula AMX 3} and those represented by the general formula A ₂ MX ₄ . Here, M refers to a divalent cation, A refers to a monovalent cation, and X refers to a monovalent anion. As the perovskite semiconductor compound, an appropriate one can be selected according to the type of semiconductor device.

The monovalent cation A is not particularly limited, but for example, the one described in the above-mentioned Galasso's book can be used. More specific examples include cations containing Group 1 and Group 13-16 elements of the Periodic Table. Among these, cesium ion, rubidium ion, ammonium ion which may have a substituent, or phosphonium ion which may have a substituent is preferable. Examples of ammonium ions that may have a substituent include primary ammonium ions or secondary ammonium ions. There are no particular restrictions on the substituents. Specific examples of ammonium ions that may have a substituent include alkylammonium ions or arylammonium ions. In particular, monoalkylammonium ions having a three-dimensional crystal structure are preferable in order to avoid steric hindrance, and from the viewpoint of improving stability, alkylammonium ions substituted with one or more fluorine groups are preferably used. Further, a combination of two or more kinds of cations can be used as the cation A.

Specific examples of the monovalent cation A include methylammonium ion, monofluoromethylammonium ion, difluoride methylammonium ion, trifluoride methylammonium ion, ethylammonium ion, isopropylammonium ion, n-propylammonium ion, and isobutylammonium ion. , N-butylammonium ion, t-butylammonium ion, dimethylammonium ion, diethylammonium ion, phenylammonium ion, benzylammonium ion, phenethylammonium ion, guanidium ion, formamidinium ion, acetamidinium ion or imidazolium Ions and the like can be mentioned.

The divalent cation M is also not particularly limited, but is preferably a divalent metal cation or a metalloid cation. Specific examples include cations of Group 14 elements of the periodic table, and more specific examples include lead cations (Pb ²⁺ ), ^{tin cations (Sn 2+} ), and germanium cations (Ge ²⁺ ). Further, a combination of two or more kinds of cations can be used as the cation M. From the viewpoint of obtaining a stable photoelectric conversion element, it is particularly preferable to use a lead cation or two or more kinds of cations containing a lead cation.

Examples of monovalent anion X include halide ion, acetate ion, nitrate ion, sulfate ion, borate ion, acetylacetonate ion, carbonate ion, citrate ion, sulfur ion, tellurium ion, thiocyanate ion, and titanoic acid. Examples thereof include an ion, a zirconate ion, a 2,4-pentandionato ion, a siliceous fluorine ion and the like. In order to adjust the bandgap, X may be one kind of anion or a combination of two or more kinds of anions. Among them, it is preferable to use a halide ion or a combination of a halide ion and another anion as X. Examples of the halide ion X include chloride ion, bromide ion, iodide ion and the like. It is preferable to use iodide ions from the viewpoint of not widening the band gap of the semiconductor too much.

Preferred examples of the perovskite semiconductor compound include an organic-inorganic perovskite semiconductor compound, and in particular, a halide-based organic-inorganic perovskite semiconductor compound. Specific examples of perovskite semiconductor _{compound, CH 3 NH 3 PbI 3,} CH 3 NH 3 PbBr 3, CH 3 NH 3 PbCl 3, CH 3 NH 3 SnI 3, CH 3 NH 3 SnBr 3, CH 3 NH 3 SnCl 3 , CH ₃ NH ₃ PbI _(3-x) Cl _x , CH ₃ NH ₃ PbI _(3-x) Br _x , CH ₃ NH ₃ PbBr _(3-x) Cl _x , CH ₃ NH ₃ Pb _(1-y) Sn _y I ₃ , CH ₃ NH ₃ Pb _(1-y) Sn _y Br ₃ , CH ₃ NH ₃ Pb _(1-y) Sn _y Cl ₃ , CH ₃ NH ₃ Pb _(1-y) Sn _y I _{(3) -X)} Cl _x , CH ₃ NH ₃ Pb _(1-y) Sn _y I _(3-x) Br _x , and CH ₃ NH ₃ Pb _(1-y) Sn _y Br _(3-x) Cl _x , and , CFH ₂ NH ₃ , CF ₂ HNH ₃ , or CF ₃ NH ₃ is used _{instead of CH 3} NH ₃ in the above compounds. Note that x indicates an arbitrary value of 0 or more and 3 or less, and y indicates an arbitrary value of 0 or more and 1 or less.

The semiconductor layer may contain two or more types of perovskite semiconductor compounds. For example, two or more types of perovskite semiconductor compounds in which at least one of A, B, and X is different may be contained in the semiconductor layer.

The amount of the perovskite semiconductor compound contained in the semiconductor layer is preferably 50% by mass or more, more preferably 70% by mass or more, and more preferably 80% by mass or more so that good semiconductor characteristics can be obtained. .. There is no particular upper limit.

The semiconductor layer further contains additives. Examples of the additive include a compound having a pKa value lower than the pKa value of the monovalent cation A constituting the perovskite semiconductor compound (the pKa value when the proton is desorbed from the monovalent cation A). In the present specification, the pKa value refers to the value at 25 ° C. in water, and the pKa value of each compound shall be in accordance with the value described in "Revised 5th Edition Chemistry Handbook" edited by the Chemical Society of Japan. However, for compounds for which the pKa value is not described in the "Revised 5th Edition Chemistry Handbook" edited by the Chemical Society of Japan, it can be calculated using a fully automatic physical property parameter measuring device (Sirius analytical T3, manufactured by CTC Life Science Corporation). can.

When the compound of the additive has a plurality of pKa, the pKa value of the first stage ionization (when the proton is first desorbed) shall be referred to. The additive may be a mixture of two or more substances.

According to the present inventors, it has been found that when the semiconductor layer contains the above compound, the performance of the semiconductor device is improved, for example, the short-circuit current density and the photoelectric conversion efficiency are improved in the photoelectric conversion element. rice field. The reason is not clear, but the following reasons can be considered. For example, the perovskite compound uses, for example, AX (A is a monovalent cation, X is a monovalent anion) and MX ₂ (M is a divalent cation, X is a monovalent anion) as precursors, as described later. Can be formed. At this time, it is important that the monovalent cation A constituting the perovskite semiconductor compound is coordinated with the monovalent anion X, but a compound having a pKa value lower than the pKa of the monovalent cation A is added. It is considered that the activation of the monovalent cation salt can be promoted by the above. Therefore, it is considered that the reactivity with the perovskite semiconductor (MX ₂ ) constituting the perovskite semiconductor can be enhanced, the crystallization of the perobskite semiconductor can be promoted, and the perovskite semiconductor having a large crystal size can be obtained. As a result, it is considered that the short-circuit current density and the photoelectric conversion efficiency are improved.

Among the above, in order to further activate the monovalent cationic salt, the additive is preferably a compound having a pKa value of 7 or less, more preferably a compound having a pKa value of 6 or less, and a compound having a pKa value of 5 or less. Is particularly preferable. On the other hand, in order to improve the performance of the semiconductor device, the additive is preferably a compound having a pKa value of −5 or more. In addition, using a compound having a pKa value of -5 or more also means that when a semiconductor layer is formed by using a solution process, it is difficult for the additive to react with a polar solvent such as N, N-dimethylformamide, which is often used. preferable. More preferably, the additive is a compound having a pKa of -2 or more, and even more preferably a compound having a pKa of 0 or more.

The above compound is not particularly limited, but is an atom selected from the elements of the oxo group (X = O, X are Group 14, Group 15, and Group 16) in order to improve the solubility in the perovskite precursor solution. ) And an organic compound having a hydroxyl group. Among them, the compound having a carboxyl group, a phosphoric acid group, a sulfonic acid group, or a carboxylic acid anhydride group is preferable in order to promote the interaction with the perovskite semiconductor. The molecular weight of the compound is preferably 50 or more, more preferably 80 or more, and on the other hand, the molecular weight is preferably 500 or less so as not to enhance the insulating property in the semiconductor layer, 300. The following is more preferable.

The compound having a carboxyl group is not particularly limited, but for example, tartaric acid, L-ascorbic acid, malic acid, citric acid, benzoic acid, o-chlorobenzoic acid, m-nitrobenzoic acid, salicylic acid, trichloroacetic acid, etc. Dichloroacetic acid or phthalic acid can be mentioned.

The carboxyl group also includes a vinyl carboxylic acid group (C (= O) -C = C-OH) as that L-ascorbic acid has.

The compound having a phosphoric acid group is not particularly limited, and examples thereof include glyphosate, 2-aminopropylphosphonic acid, aminomethylphosphonic acid, and methylene diphosphonic acid.

The compound having a sulfonic acid group is not particularly limited, and examples thereof include sulfamic acid, aminoethyl sulfonic acid, 4-morpholine ethane sulfonic acid, and aminomethyl sulfonic acid.

The compound having an carboxylic acid anhydride group is not particularly limited, and examples thereof include L-ascorbic acid, succinic anhydride, and phthalic anhydride.

The compound having an carboxylic acid anhydride group may be a compound in which the pKa value of the compound obtained by hydration is lower than the pKa value of the monovalent cation A.

Among the above, it is preferable to use a non-volatile compound or a non-volatile compound as the additive. For example, when hydrogen iodide is used as an additive as described in Non-Patent Document 1, hydrogen iodide volatilizes during the film formation of the semiconductor layer, so that no additive remains in the semiconductor layer. Therefore, the efficiency cannot be improved because the crystal size of the perovskite semiconductor compound cannot be increased. Therefore, from the viewpoint of preventing the additive from volatilizing, the additive is preferably solid at 25 ° C. and 1 atm. From the viewpoint of preventing volatilization when forming the semiconductor layer and leaving the compound in the semiconductor layer, the boiling point of the compound at 1 atm is preferably 100 ° C. or higher, preferably 150 ° C. or higher. Is more preferable, and it is particularly preferable that the temperature is 200 ° C. or higher. Further, since the compound preferably exists as a solid acid in the semiconductor layer, the melting point of the compound at 25 ° C. and 1 atm is preferably 100 ° C. or higher.

As the additive, a material other than the constituent components of the perovskite semiconductor can be used. For example, when the semiconductor layer contains the perovskite semiconductor represented by _{AMX 3} or A ₂ MX _{4 as described above, AMX 3} , A ₂ MX ₄ , AX or MX ₂ but other additives can be used. Further, in one embodiment, an additive that is not a salt of HX or X is used, and in a further embodiment, an additive that is not a salt of A or M is used. In addition, additives having properties different from those of the constituents of the perovskite semiconductor can be used. For example, when the semiconductor layer contains a halide-based organic-inorganic perovskite semiconductor compound, an additive other than a hydrogen halide or a halide salt can be used.

The amount of the additive contained in the semiconductor layer is not particularly limited as long as the effect can be obtained. The amount of the additive contained in the semiconductor layer is 1.0 mol with respect to the amount of the divalent cation M constituting the perovskite semiconductor compound contained in the semiconductor layer so that the effect of the additive is more exerted. % Or more is preferable, 2.0 mol% or more is more preferable, 5.0 mol% or more is further preferable, and 10 mol% or more may be used. On the other hand, the amount of the additive contained in the semiconductor layer is 100 mol% or less with respect to the amount of the divalent cation M constituting the perovskite semiconductor compound contained in the semiconductor layer so that the semiconductor characteristics can be maintained well. It is preferably 75 mol% or less, more preferably 50 mol% or less.

In addition to the perovskite semiconductor compound and the additive, other compounds may be added to the semiconductor layer. Examples of other compounds include inorganic compounds such as halides, oxides, or inorganic salts such as sulfides, sulfates, nitrates or ammonium salts. In this case, the ratio of the perovskite semiconductor compound and the above-mentioned additive in the semiconductor layer is preferably 50% by mass or more, more preferably 70% by mass or more so that the semiconductor characteristics of the semiconductor layer are well exhibited. , More preferably 90% by mass or more. Further, the semiconductor layer may have a laminated structure formed by a plurality of layers containing different materials or having different components.

The thickness of the semiconductor layer is not particularly limited, and can be appropriately selected depending on the use of the semiconductor layer. As an example, the thickness of the semiconductor layer may be 0.5 nm or more and 500 nm or less.

The method for forming the semiconductor layer is not particularly limited, and any method can be used. For example, a semiconductor layer can be formed by a coating method using a coating liquid containing the above additives. In particular, when the semiconductor layer is formed by the coating method in this way, as described above, the pKa of the additive is preferably a compound of 7 or less, more preferably 6 or less, and 5 or less. On the other hand, it is preferably −5 or more, more preferably −2 or more, and further preferably 0 or more. Specific examples include a method of forming a semiconductor layer by applying a coating liquid containing a perovskite semiconductor compound or a precursor thereof and an additive.

The perovskite semiconductor compound precursor refers to a material that can be converted into a perovskite semiconductor compound after the coating liquid is applied. As a specific example, there is a perovskite semiconductor compound precursor that can be converted into a perovskite semiconductor compound by heating. For example, by heating the film obtained by applying the coating liquid, the perovskite semiconductor compound precursor can be converted into the perovskite semiconductor compound to form a semiconductor layer containing the perovskite semiconductor compound and the additive. .. Specific examples of the perovskite semiconductor compound precursor include a compound represented by the following formula (2) and / or the following formula (3), which can be converted into a perovskite semiconductor compound represented by the following formula (1) by heating. Examples include the compounds represented.

As an example, a method of preparing a coating liquid containing a compound represented by the following formula (2), a compound represented by the following formula (3), an additive, and a solvent, and applying the coating liquid. Can be mentioned. Such a coating liquid can be prepared by heating and stirring the compound in the solution. According to this method, the active layer 103 containing the compound represented by the following formula (1) and the additive can be produced.

AMX ₃ ... (1)
AX ・ ・ ・ (2)
MX ₂ ... (3)
The definitions of A, M and X are as described above. Specific examples of AX include alkylammonium halides, and specific examples of _{MX 2 include metal halides.} AX and MX ₂ are precursors of the belobskite semiconductor compound AMX _3.

The heating temperature at the time of heating stirring or heating annealing is preferably 60 ° C. or higher from the viewpoint of sufficiently promoting the reaction of the compound, while it is preferably 80 ° C. or lower from the viewpoint of avoiding side reactions. The heating and stirring time is preferably 2 hours or more from the viewpoint of sufficiently promoting the reaction of the compound, and preferably 24 hours or less from the viewpoint of improving the production efficiency. The heating and stirring temperature is preferably 60 ° C. or higher, and more preferably 65 ° C. or higher. The annealing method is not particularly limited, and may be performed by a hot plate under normal pressure or reduced pressure, or by a near-infrared heating device (NIR).

The mole fraction (2/3) of the compound represented by the formula (2) with respect to the compound represented by the formula (3) is not particularly limited. However, if the compound represented by the formula (3) remains in the active layer, the conversion efficiency of the photoelectric conversion element tends to decrease. Further, even if the compound represented by the formula (2) can be removed by the heat treatment described later, it is often difficult to remove the compound represented by the formula (3) by heating. Therefore, it is preferable to form the active layer 103 so that the compound represented by the formula (3) does not remain in the layer. From this point, the molar fraction (2/3) of the compound represented by the formula (2) to the compound represented by the formula (3) is preferably 100 mol% or more, while 600 mol% or less. It is preferably present, and particularly preferably 400 mol% or less.

The coating liquid used in the coating method can be prepared by dissolving a perovskite semiconductor compound or a precursor thereof and an additive in a solvent. The solvent is not particularly limited as long as the perovskite semiconductor compound and the additive are dissolved. Examples of solvents include aliphatic hydrocarbons such as hexane, heptane, octane, isooctane, nonane or decane; aromatic hydrocarbons such as toluene, xylene, mesitylene, cyclohexylbenzene, chlorobenzene or orthodichlorobenzene; cyclopentane, Aliphatic hydrocarbons such as cyclohexane, methylcyclohexane, cycloheptane, cyclooctane, tetraline or decalin; lower alcohols such as methanol, ethanol or propanol; fats such as acetone, methylethylketone, cyclopentanone, dimethylsulfoxide or cyclohexanone Group Ketones; Aromatic Ketones such as Acetphenone or Propiophenone; Esters such as Ethyl Acetate, Butyl Acetate, γ-Butyrolactone, or Methyl Lactate; Halogen Hydrocarbons such as Chloride, Methylene Chloride, Dichloroethane, Trichloroethane or Trichloroethylene ; Ethers such as ethyl ether, tetrahydrofuran or dioxane; or amides such as dimethylformamide or dimethylacetamide can be mentioned.

When a perovskite semiconductor compound is used, the solvent of the coating liquid is Blandrup, J. Mol. The solubility parameter (SP value) described in "Polymer Handbook, 4th Ed." Is preferably 9 or more, and particularly preferably 10 or more. For example, N, N-dimethylformamide, N, N-dimethylacetamide, N, N-diethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide, pyridine, γ-butyrolactone and the like can be mentioned. As the solvent, a mixed solvent of two or more kinds of solvents may be used. Even when a mixed solvent is used, the solubility parameter of at least one of the mixed solvents is preferably 10 or more.

Such a composition containing a perovskite semiconductor compound or a perovskite semiconductor compound precursor and the above-mentioned additives can be used as a composition for forming a semiconductor layer. In the above example, a coating liquid containing a perovskite semiconductor compound or a precursor thereof, an additive, and a solvent is used as a composition for forming a semiconductor layer. The composition may contain an additional compound, but the proportion of the perovskite semiconductor compound or its precursor and the above-mentioned additive in the composition is preferably 50% by mass or more, more preferably 50% by mass or more. Is 70% by mass or more, more preferably 90% by mass or more.

The ratio of the perovskite semiconductor compound or its precursor and the additive contained in the composition is not particularly limited. In order to better exert the effect of the additive, the amount of the additive contained in the composition is 1. It is preferably 0 mol% or more, more preferably 2.0 mol% or more, further preferably 5.0 mol% or more, and may be 10 mol% or more. On the other hand, the amount of the additive contained in the semiconductor layer is 100 mol% or less with respect to the amount of the divalent cation M constituting the perovskite semiconductor compound contained in the semiconductor layer so that the semiconductor characteristics can be maintained well. It is preferably 75 mol% or less, more preferably 50 mol% or less.

Further, the concentration of the precursor of the perovskite semiconductor compound contained in the composition is not particularly limited, and can be appropriately selected so as to form a semiconductor layer having an appropriate thickness. The concentration of the precursor of the perovskite semiconductor compound is preferably 10% by weight or more, more preferably 15% by weight or more, while preferably 60% by weight or less, and further, so that the coating film formation proceeds smoothly. It is preferably 45% by weight or less.

Any method can be used as the coating method of the coating liquid, and for example, a spin coating method, an inkjet method, a doctor blade method, a drop casting method, a reverse roll coating method, a gravure coating method, a kiss coating method, a roll brushing method, etc. Examples thereof include a spray coating method, an air knife coating method, a wire barber coating method, a pipe doctor method, an impregnation / coating method, and a curtain coating method.

The semiconductor layer can be formed by applying the coating liquid and then drying it, and if necessary, performing a treatment of converting the perovskite semiconductor compound precursor into a perovskite semiconductor compound. The drying method is not particularly limited, and for example, heat drying may be performed.

Up to this point, a case where a semiconductor layer is formed by using a coating liquid containing a compound represented by the above formula (2), a compound represented by the above formula (3), an additive, and a solvent has been described. However, the method of forming the semiconductor layer by the coating method is not limited to this. For example, one of a coating liquid containing a perovskite semiconductor compound precursor represented by the above formula (2) and a coating liquid containing a perovskite semiconductor compound precursor represented by the above formula (3) was applied. Later, the other may be further applied. After that, a semiconductor layer can be formed by performing a process of converting the perovskite semiconductor compound precursor into a perovskite semiconductor compound. In this case, if the additive is contained in at least one of the coating liquid containing the compound represented by the above formula (2) and the coating liquid containing the compound represented by the above formula (3). good. Further, even if a coating liquid containing an additive is applied in addition to the coating liquid containing the compound represented by the above formula (2) and the coating liquid containing the compound represented by the above formula (3). good. As described above, the semiconductor layer can be formed by various methods using the coating liquid containing the above-mentioned additives.

The method for manufacturing the semiconductor device according to the present invention is not particularly limited, and for example, it can be manufactured by the following method. That is, a semiconductor device can be manufactured by a step of forming a semiconductor layer on a base material on which an electrode is formed and a step of forming an electrode on the semiconductor layer. In the step of forming the semiconductor layer, the semiconductor layer can be formed by the method described above.

Hereinafter, as an example of the semiconductor device according to the present invention, a field effect transistor element, an electroluminescent element, a photoelectric conversion element, and a solar cell will be described in detail.

<2. Field effect transistor (FET)>
The field effect transistor (FET) element according to the present invention has a semiconductor layer, a source electrode and a drain electrode which are a pair of electrodes, and a gate electrode. This semiconductor layer contains a perovskite semiconductor compound and an additive as described above.

Hereinafter, the FET element according to the embodiment will be described in detail. FIG. 1 is a diagram schematically showing a structural example of the FET element according to the present invention. In FIG. 1, 51 is a semiconductor layer, 52 is an insulator layer, 53 and 54 are source electrodes and drain electrodes, 55 is a gate electrode, and 56 is a substrate. The semiconductor layer 51 contains a perovskite semiconductor compound and an additive. However, in another embodiment, the FET element has a semiconductor layer containing a perovskite semiconductor compound and an additive, which is different from the semiconductor layer 51 which acts as a channel between the source electrode 53 and the drain electrode 54. May be good. Although FET elements having different structures are shown in FIGS. 1A to 1D, structural examples of the FET elements according to the present invention are shown. There are no particular restrictions on these constituent members constituting the FET element and the manufacturing method thereof, and well-known techniques can be used. For example, the techniques described in publicly known documents such as International Publication No. 2013/180230 or JP2012-191194 can be used.

In the FET element according to one embodiment, the semiconductor layer 51 is produced by forming a semiconductor on the base material 56 directly or via another layer in the form of a film. There is no limitation on the film thickness of the semiconductor layer 51. For example, in the case of a horizontal field effect transistor element, the characteristics of the element do not depend on the film thickness of the semiconductor layer 51 as long as it is equal to or more than a predetermined film thickness. However, since the leakage current often increases when the film thickness becomes too thick, the film thickness of the semiconductor layer is preferably 0.5 nm or more, more preferably 10 nm or more, and preferably 1 μm from the viewpoint of cost. Below, it is more preferably 200 nm or less.

As the characteristics of the semiconductor layer 51, the carrier mobility at room temperature is preferably 1.0 x ^10-6 cm ² / V · s or more, more preferably 1.0 × 10 ^-5 cm ² / V · s or more, and more preferably 5. 0x10 ^-5 cm ² / V · s or more, and particularly preferably ^1.0x10 -4 ^cm 2 / V · s or more.

<3. Electroluminescent element (LED)>
The electroluminescent device (LED) according to the present invention has a pair of electrodes, an anode and a cathode, and a light emitting layer, which is a semiconductor layer arranged between the electrodes. The electroluminescent device is a self-luminous device that utilizes the principle that a fluorescent substance emits light by the recombination energy of holes injected from an anode and electrons injected from a cathode by applying an electric field. In one embodiment, the light emitting layer contains a perovskite semiconductor compound and an additive as described above. However, in another embodiment, the electroluminescent device may have a semiconductor layer containing a perovskite semiconductor compound and an additive, which is different from the light emitting layer. For example, the electron transport layer or the hole transport layer may be a semiconductor layer containing a perovskite semiconductor compound and an additive.

FIG. 2 is a cross-sectional view schematically showing an embodiment of an electroluminescent device according to the present invention. In FIG. 2, reference numeral 31 is a base material, 32 is an anode, 33 is a hole injection layer, 34 is a hole transport layer, 35 is a light emitting layer, 36 is an electron transport layer, 37 is an electron injection layer, 38 is a cathode, and 39. Indicates an electroluminescent device. The light emitting layer 35 contains a perovskite semiconductor compound and an additive. It is not necessary for the electroluminescent element to have all of these constituent members, and the necessary constituent members can be arbitrarily selected. For example, it is not always necessary to provide the hole injection layer 33, the hole transport layer 34, the electron transport layer 36, and the electron injection layer 37. There are no particular restrictions on these constituent members constituting the electroluminescent element and the method for manufacturing the same, and a well-known technique can be used. For example, the techniques described in publicly known documents such as International Publication No. 2013/180230 or JP2012-191194 can be used.

There is no limitation on the method of forming the light emitting layer 35. For example, a wet film forming method or a dry film forming method can be used. Further, for the purpose of improving the luminous efficiency of the element, changing the emission color, improving the driving life of the element, etc., the host material is doped with another compound such as a fluorescent dye or a phosphorescent metal complex to emit light. Layer 35 may be made. For example, by doping with a fluorescent dye
1) Improvement of emission efficiency by high-efficiency fluorescent dye 2) Variable emission wavelength by selection of fluorescent dye 3) Fluorescent dye that causes concentration quenching can be used 4) Fluorescent dye with poor thin film property can also be used 5) It is expected that the drive stability will be improved by eliminating the charge trap.

Further, mixing a hole transporting material in the light emitting layer 35 is also effective for the purpose of improving the driving stability of the device. The amount of the hole transporting material mixed in the light emitting layer 35 is preferably in the range of 5 to 50% by mass.

The film thickness of the light emitting layer 35 is not limited, and is preferably 3 nm or more, more preferably 10 nm or more, preferably 300 nm or less, still more preferably, so that the amount of light emitted can be secured while satisfying the conditions desired for the light emitting layer 35. It is 100 nm or less.

Note that FIG. 2 is merely an embodiment of the electroluminescent device according to the present invention, and the electroluminescent device according to the present invention is not limited to the illustrated configuration. For example, the laminated structure opposite to that shown in FIG. 2, that is, the cathode 38, the electron injection layer 37, the electron transport layer 36, the light emitting layer 35, the hole transport layer 34, the hole injection layer 33, and the anode are formed on the substrate 31. It is also possible to stack 32 in this order.

The configuration of the electroluminescent device according to the present invention is not particularly limited, and the anode and cathode form an XY matrix regardless of whether the device is a single device or an device having a structure arranged in an array. It may be an element having an arranged structure.

<4. Photoelectric conversion element>
The photoelectric conversion element according to the present invention has a cathode and an anode which are a pair of electrodes, and an active layer which is a semiconductor layer arranged between the electrodes. Further, the photoelectric conversion element according to one embodiment may have other components including a base material, an electron extraction layer, and a hole extraction layer. In one embodiment, the active layer contains the perovskite semiconductor compound and additives as described above. However, in another embodiment, the photoelectric conversion element may have a semiconductor layer containing a perovskite semiconductor compound and an additive, which is different from the active layer. For example, the electron extraction layer, the hole extraction layer, or the like may be a semiconductor layer containing a perovskite semiconductor compound and an additive.

FIG. 3 is a cross-sectional view schematically showing an embodiment of the photoelectric conversion element according to the present invention. The photoelectric conversion element shown in FIG. 3 is a photoelectric conversion element used in a general thin-film solar cell, but the photoelectric conversion element according to the present invention is not limited to the one shown in FIG. The photoelectric conversion element 100 according to the embodiment of the present invention includes a base material 108, an anode (electrode) 101, a hole extraction layer (buffer layer) 102, an active layer 103, an insulator layer 104, and an electron extraction layer (buffer layer). 105, the work function tuning layer 106 and the cathode (electrode) 107 have a layer structure formed in this order. The active layer 103 contains a perovskite semiconductor compound and an additive. It is not always necessary to provide the hole extraction layer 102, the insulator layer 104, the electron extraction layer 105, and the work function tuning layer 106. Further, the work function tuning layer may exist between the anode 101 and the hole extraction layer 102.

The configuration of the photoelectric conversion element according to the present invention is not limited to that shown in FIG. For example, the photoelectric conversion element 100 may have a layer structure in which the base material 108, the cathode 107, the active layer 103, and the anode 101 are formed in this order, and further, the work function tuning layer 106, the electron extraction layer 105, and the like. It may have an insulator layer 104, a hole extraction layer 102, and the like. Further, the photoelectric conversion element 100 may have components other than the components shown in FIG.

<4-1. Active layer (103)>
The active layer 103 is a layer on which photoelectric conversion is performed. When the photoelectric conversion element 100 receives light, the light is absorbed by the active layer 103 to generate carriers, and the generated carriers are taken out from the anode 101 and the cathode 107.

In the present embodiment, the above-mentioned semiconductor layer can be used as the active layer 103, and specifically, a semiconductor layer containing a perovskite semiconductor compound and an additive can be used as the active layer 103. A solar cell having such an active layer 103 is known as a perovskite solar cell. In the perovskite semiconductor, a perovskite semiconductor compound having a perovskite structure forms a crystal. In such a crystal, rapid charge separation occurs and the diffusion distance of holes and electrons is long, so that efficient charge separation occurs. The perovskite semiconductor compound is not particularly limited, and the above-mentioned ones can be used. From the viewpoint of improving the photoelectric conversion efficiency, it is preferable to use a semiconductor compound having an energy bandgap of 1.0 eV or more and 3.5 eV or less as the perovskite semiconductor compound.

However, when the layer other than the active layer 103 is a layer containing a perovskite semiconductor compound and an additive, the structure of the active layer 103 is not particularly limited. For example, the active layer 103 is a heterojunction type active layer containing a layer containing a p-type semiconductor compound and a layer containing an n-type semiconductor compound, or a layer in which a p-type semiconductor compound and an n-type semiconductor compound are mixed ( It can be a bulk heterotype active layer having i-layer).

There is no particular limitation on the thickness of the active layer 103. The thickness of the active layer 103 is preferably 5 nm or more, more preferably 10 nm or more, more preferably 50 nm or more, and particularly preferably 120 nm or more in that more light can be absorbed. On the other hand, the thickness of the active layer 103 is preferably 500 nm or less, more preferably 400 nm or less, and more preferably 300 nm or less in that the series resistance is lowered.

The method for forming the active layer 103 is not particularly limited, and any method can be used. Specific examples include a coating method and a vapor deposition method (or a co-evaporation method). It is preferable to use the coating method because the active layer 103 can be easily formed. As a method for forming the active layer 103 by the coating method, the same method as the above-mentioned method for forming the semiconductor layer can be used.

After applying the coating liquid, it is preferable to perform heat drying. The solvent coordinated by heating and the remaining compound represented by the formula (2) are removed from the layer to promote crystallization, and the photoelectric conversion efficiency tends to be improved. Since the progress of crystallization depends on the concentration of the coating liquid, it is preferable to shorten the heating time when the concentration of the coating liquid is low or the content of the solvent is low.

The heating temperature at this time is not particularly limited, but is preferably 70 ° C. or higher, more preferably 90 ° C. or higher, from the viewpoint of sufficiently promoting crystallization, while decomposing and side reactions of the perovskite semiconductor compound. In order to suppress it, it is preferably 150 ° C. or lower, more preferably 130 ° C. or lower, and more preferably 120 ° C. or lower. The heating time is also not particularly limited, but from the viewpoint of sufficiently promoting crystallization, it is preferably 10 minutes or more, more preferably 30 minutes or more, and more preferably 1 hour or more, while improving production efficiency. From the viewpoint of allowing the mixture to grow, it is preferably 3 hours or less, more preferably 2 hours or less. These heatings may be performed under normal pressure or reduced pressure.

<4-2. Buffer layer (102,105)>
The buffer layer can usually be classified into an electron extraction layer and a hole extraction layer. In one embodiment, the photoelectric conversion element 100 has a hole extraction layer 102 between the anode 101 and the active layer 103, and an electron extraction layer 105 between the active layer 103 and the cathode 107. However, the photoelectric conversion element 100 may have only one of the hole extraction layer 102 and the electron extraction layer 105, or may have neither the hole extraction layer 102 nor the electron extraction layer 105. good.

The hole extraction layer 102 and the electron extraction layer 105 are preferably arranged so as to sandwich the active layer 103 between the pair of electrodes (101, 107). That is, when the photoelectric conversion element 100 includes both the hole extraction layer 102 and the electron extraction layer 105, the anode (electrode) 101, the hole extraction layer 102, the active layer 103, the electron extraction layer 105, and the cathode (electrode) 107. Can be arranged in this order. When the photoelectric conversion element 100 includes the hole extraction layer 102 and does not include the electron extraction layer 105, the anode (electrode) 101, the hole extraction layer 102, the active layer 103, and the cathode (electrode) 107 are arranged in this order. Can be done. Further, at least one of the hole extraction layer 102 and the electron extraction layer 105 may be composed of a plurality of different films.

(Hole extraction layer)
The material of the hole extraction layer 102 is not particularly limited, and is not particularly limited as long as it is a material capable of improving the efficiency of extraction of holes from the active layer 103 to the anode 101. Specifically, the inorganic compound, the organic compound, or the organic-inorganic perovskite compound according to the present invention described in publicly known documents such as International Publication No. 2013/171517, International Publication No. 2013/180230 or JP2012-191194A. Can be mentioned. For example, examples of the inorganic compound include metal oxides such as copper oxide, nickel oxide, manganese oxide, iron oxide, molybdenum oxide, vanadium oxide and tungsten oxide. Examples of the organic compound include a conductive polymer (for example, PEDOT: PSS or doped P3HT) obtained by doping polythiophene, polypyrrole, polyacetylene, triphenylenediamine, polyaniline, etc. with sulfonic acid, iodine, etc., and a sulfonyl group as a substituent. Examples thereof include polythiophene derivatives, conductive organic compounds such as arylamines, nafion, or lithium-doped spiro-OMeTAD.

The overall film thickness of the hole extraction layer 102 is not particularly limited, but is preferably 0.5 nm or more. On the other hand, it is preferably 400 nm or less, more preferably 200 nm or less. When the film thickness of the hole extraction layer 102 is 0.5 nm or more, the function as a buffer material is well fulfilled, and when the film thickness of the hole extraction layer 102 is 400 nm or less, holes can be easily extracted. Therefore, the photoelectric conversion efficiency can be improved.

There is no limitation on the method of forming the hole extraction layer 102. When a sublimable compound is used, it can be formed by a dry film forming method such as a vacuum vapor deposition method. When a compound soluble in a solvent is used, it can be formed by a wet film forming method such as a spin coating method or an inkjet method. As the solvent, the solvent mentioned in the description of the method for forming the active layer 103 can be used.

(Electronic extraction layer)
The material of the electron extraction layer 105 is not particularly limited, and is not particularly limited as long as it is a material capable of improving the efficiency of electron extraction from the active layer 103 to the cathode 107. Specifically, the inorganic compound, the organic compound, or the organic-inorganic perovskite compound according to the present invention described in publicly known documents such as International Publication No. 2013/171517, International Publication No. 2013/180230 or JP2012-191194A. Can be mentioned. For example, examples of the inorganic compound include salts of alkali metals such as lithium, sodium, potassium and cesium, and metal oxides such as zinc oxide, titanium oxide, aluminum oxide and indium oxide. Examples of the organic compound include vasocuproin (BCP), vasophenanthrene (Bphen), (8-hydroxyquinolinato) aluminum (Alq3), boron compound, oxadiazole compound, benzoimidazole compound, naphthalenetetracarboxylic acid anhydride (NTCDA), and the like. Examples thereof include phosphine compounds having a double bond with a Group 16 element of the periodic table such as perylene tetracarboxylic acid anhydride (PTCDA), fullerene compound, or phosphine oxide compound or phosphine sulfide compound.

There is no particular limitation on the method of forming the electron extraction layer 105. When a sublimable compound is used as a material, it can be formed by a dry film forming method such as a vacuum vapor deposition method. When a solvent-soluble compound is used as the material, it can be formed by a wet film forming method such as a spin coating method or an inkjet method. As the solvent, the solvent mentioned in the description of the method for forming the active layer 103 can be used. When the wet film forming method is used, any method can be used as the coating method of the coating liquid containing the material of the electron extraction layer 105. Examples thereof include a spin coating method, a gravure coating method, a kiss coating method, a roll brushing method, a spray coating method, an air knife coating method, a wire barber coating method, a pipe doctor method, an impregnation / coating method and a curtain coating method. Further, as the coating method, only one kind of method may be used, or two or more kinds of methods may be used in combination.

The overall film thickness of the electron extraction layer 105 is not particularly limited, but is preferably 0.5 nm or more, more preferably 1 nm or more, more preferably 5 nm or more, and particularly preferably 10 nm or more. On the other hand, it is preferably 1 μm or less, more preferably 700 nm or less, more preferably 400 nm or less, and particularly preferably 200 nm or less. When the film thickness of the electron extraction layer 105 is within the above range, uniform coating can be facilitated, and the electron extraction function can be well exhibited.

<4-3. Electrodes (101, 107)>
The electrode has a function of collecting holes and electrons generated by light absorption. Therefore, as the pair of electrodes, it is preferable to use an anode 101 suitable for collecting holes and a cathode 107 suitable for collecting electrons. One of the pair of electrodes may be translucent, and both may be translucent. Translucent means that sunlight is transmitted by 40% or more. Further, it is preferable that the solar ray transmittance of the transparent electrode is 70% or more because more light passes through the transparent electrode and reaches the active layer 103. The light transmittance can be measured with a spectrophotometer (for example, U-4100 manufactured by Hitachi High-Tech).

There are no particular restrictions on the constituent members of the anode 101 and the cathode 107 and the manufacturing method thereof, and well-known techniques can be used. For example, the members described in publicly known documents such as International Publication No. 2013/171517, International Publication No. 2013/180230, and Japanese Patent Application Laid-Open No. 2012-191194, and methods for producing the same can be used.

<4-4. Work function tuning layer (106)>
The work function tuning layer 106 adjusts the work function of the anode 101 or the cathode 107. However, if the anode 101 or cathode 107 can function properly, it is not necessary to provide the work function tuning layer 106.

The type of the work function tuning layer 106 is not particularly limited, and known ones can be used. As an example of the material of the work function tuning layer 106, an amine-based polymer or oligomer such as polyethyleneimine ethoxylate (PEIE) or branched polyethyleneimine (PEI) is preferable because it is easy to form a film by coating. In this case, from the viewpoint of increasing the solubility in the organic solvent, the molecular weight of the material of the work function tuning layer 106 is preferably 100 or more, more preferably 1000 or more, particularly preferably 10000, while preferably 1000000 or less. It is preferably 500,000 or less, and particularly preferably 200,000 or less.

There is no limitation on the method of forming the work function tuning layer 106. When a sublimable compound is used, it can be formed by a dry film forming method such as a vacuum vapor deposition method. When a compound soluble in a solvent is used, it can be formed by a wet film forming method such as a spin coating method or an inkjet method. As the solvent, the solvent mentioned in the description of the method for forming the active layer 103 can be used.

<4-5. Insulator layer (104)>
The insulator layer 104 refers to a layer containing an insulator that does not allow direct current to pass through. By providing such an insulator layer, it is possible to effectively prevent substances such as moisture from reaching the active layer 103. On the other hand, the function of the photoelectric conversion element 100 is maintained even if a thin insulator layer is provided. It is considered that this is because carriers, which are electrons or holes, pass through the insulator layer due to the tunnel effect.

The position of the insulator layer 104 is not limited to between the active layer 103 and the electron extraction layer 105. The photoelectric conversion element 100 may have an insulator layer at another position between the active layer 103 and the electrodes (101, 107). For example, an insulator layer 104 can be provided between the active layer 103 and a surface on which moisture easily penetrates (for example, the cathode 107) so as to prevent moisture or the like from reaching the active layer 103.

The material of the insulator layer 104 is not particularly limited, and for example, a fluororesin or a silicon resin can be used. From the viewpoint of improving the moisture resistance of the insulator layer, the thickness of the insulator layer is preferably 1.0 nm or more, more preferably 5.0 nm or more, and particularly preferably 10 nm or more. Further, from the viewpoint of promoting the movement of carriers due to the tunnel effect, the thickness of the insulator layer is preferably 30 nm or less, more preferably 25 nm or less, and particularly preferably 20 nm or less.

<4-6. Base material (108)>
The photoelectric conversion element 100 usually has a base material 108 as a support. However, the photoelectric conversion element according to the present invention does not have to have the base material 108. The material of the base material 108 is not particularly limited as long as the effect of the present invention is not significantly impaired. The materials described in 1 can be used.

<4-7. Manufacturing method of photoelectric conversion element>
The photoelectric conversion element 100 can be manufactured by forming each layer constituting the photoelectric conversion element 100 according to the above method. There is no particular limitation on the method of forming each layer constituting the photoelectric conversion element 100, and the layers can be formed by a sheet-to-sheet (many-leaf) method or a roll-to-roll method.

The roll-to-roll method is a method in which a flexible base material wound in a roll shape is unwound and processed intermittently or continuously while being wound by a winding roll. be. According to the roll-to-roll method, long substrates on the order of km can be collectively processed, so that the roll-to-roll method is more suitable for mass production than the sheet-to-sheet method. On the other hand, when each layer is to be formed by the roll-to-roll method, the film may be scratched or partially peeled off due to the contact between the film-forming surface and the roll due to its structure.

The size of the roll that can be used in the roll-to-roll method is not particularly limited as long as it can be handled by the roll-to-roll method manufacturing apparatus, but the upper limit of the outer diameter is preferably 5 m or less, more preferably 3 m or less, and more preferably. It is 1 m or less. On the other hand, the lower limit is preferably 10 cm or more, more preferably 20 cm or more, and more preferably 30 cm or more. The upper limit of the outer diameter of the roll core is preferably 4 m or less, more preferably 3 m or less, and more preferably 0.5 m or less. On the other hand, the lower limit is preferably 1 cm or more, more preferably 3 cm or more, more preferably 5 cm or more, still more preferably 10 cm or more, and particularly preferably 20 cm or more. It is preferable that these diameters are not more than the above upper limit because the roll is easy to handle, and more than the lower limit is preferable because the layer formed in each step is less likely to be broken by bending stress. .. The lower limit of the width of the roll is preferably 5 cm or more, more preferably 10 cm or more, and more preferably 20 cm or more. On the other hand, the upper limit is preferably 5 m or less, more preferably 3 m or less, and more preferably 2 m or less. It is preferable that the width is not more than the upper limit from the viewpoint of high roll handleability, and it is preferable that the width is not more than the lower limit because the degree of freedom in the size of the photoelectric conversion element 100 is increased.

Further, after laminating the anode 101 or the cathode 107, the photoelectric conversion element 100 is preferably 50 ° C. or higher, more preferably 80 ° C. or higher, while preferably 300 ° C. or lower, further preferably 280 ° C. or lower, more preferably 250 ° C. or higher. It is preferable to heat in the following temperature range (this step may be referred to as an annealing treatment step). By performing the annealing treatment step at a temperature of 50 ° C. or higher, the adhesion between each layer of the photoelectric conversion element 100, for example, the adhesion between the hole extraction layer 102 and the anode 101, the hole extraction layer 102 and the active layer 103, and the like. Is preferable because the effect of improving the temperature can be obtained. By improving the adhesion between the layers, the thermal stability and durability of the photoelectric conversion element can be improved. It is preferable to set the temperature of the annealing treatment step to 300 ° C. or lower because the possibility that the organic compound contained in the photoelectric conversion element 100 is thermally decomposed is reduced. In the annealing treatment step, stepwise heating using different temperatures within the above temperature range may be performed.

The heating time is preferably 1 minute or more, more preferably 3 minutes or more, while preferably 180 minutes or less, still more preferably 60 minutes or less, in order to improve adhesion while suppressing thermal decomposition. It is preferable that the annealing process is terminated when the open circuit voltage, short-circuit current, and fill factor, which are the parameters of the solar cell performance, reach constant values. Further, the annealing treatment step is preferably carried out under normal pressure and in an atmosphere of an inert gas in order to prevent thermal oxidation of the constituent materials. As a heating method, the photoelectric conversion element may be placed on a heat source such as a hot plate, or the photoelectric conversion element may be placed in a heating atmosphere such as an oven. Further, the heating may be performed by a batch method or a continuous method.

<4-8. Photoelectric conversion characteristics>
The photoelectric conversion characteristics of the photoelectric conversion element 100 can be obtained as follows. The photoelectric conversion element 100 is irradiated with light under the condition of AM1.5G with a solar simulator at an irradiation intensity of 100 mW / cm ² , and the current-voltage characteristics are measured. From the obtained current-voltage curve, photoelectric conversion characteristics such as photoelectric conversion efficiency (PCE), short-circuit current density (Jsc), open circuit voltage (Voc), fill factor (FF), series resistance, and shunt resistance can be obtained.

The photoelectric conversion efficiency of the photoelectric conversion element 100 is not particularly limited, but is preferably 1% or more, more preferably 1.5% or more, and more preferably 2% or more. On the other hand, there is no particular upper limit, and the higher the limit, the better. The fill factor of the photoelectric conversion element 100 is not particularly limited, but is preferably 0.6 or more, more preferably 0.7 or more, and more preferably 0.9 or more. On the other hand, there is no particular upper limit, and the higher the limit, the better.

Further, in order to put the photoelectric conversion element into practical use, it is important to have high photoelectric conversion efficiency and high durability in addition to being simple and inexpensive to manufacture. From this point of view, the durability of the photoelectric conversion efficiency before and after exposing the photoelectric conversion element 100 to the atmosphere for one week is preferably 60% or more, more preferably 80% or more, and the higher it is, the better. The durability of the photoelectric conversion efficiency can be calculated as follows based on the photoelectric conversion efficiency before and after the photoelectric conversion element 100 is exposed to the atmosphere.
Durability (%) = ((photoelectric conversion efficiency after N hours of atmospheric exposure) / (photoelectric conversion efficiency immediately before atmospheric exposure)) × 100

<5. Solar cells ＞
The photoelectric conversion element 100 according to the present invention is preferably used as a solar cell element of a solar cell, particularly a thin-film solar cell. FIG. 4 is a cross-sectional view schematically showing the configuration of a solar cell according to an embodiment of the present invention, and FIG. 4 shows a thin-film solar cell which is a solar cell according to an embodiment of the present invention. As shown in FIG. 4, the thin-film solar cell 14 according to the present embodiment includes a weather-resistant protective film 1, an ultraviolet cut film 2, a gas barrier film 3, a getter film 4, a sealing material 5, and a solar cell. The element 6, the sealing material 7, the getter material film 8, the gas barrier film 9, and the back sheet 10 are provided in this order. The thin-film solar cell 14 according to the present embodiment has the photoelectric conversion element according to the present invention as the solar cell element 6. Then, light is irradiated from the side where the weather resistant protective film 1 is formed (lower part in FIG. 4), and the solar cell element 6 generates electricity. The thin-film solar cell 14 does not have to have all of these constituent members, and the necessary constituent members can be arbitrarily selected.

There are no particular restrictions on these constituent members constituting the thin-film solar cell and the manufacturing method thereof, and well-known techniques can be used. For example, the techniques described in publicly known documents such as International Publication No. 2013/171517, International Publication No. 2013/180230, and Japanese Patent Application Laid-Open No. 2012-191194 can be used.

The use of the solar cell according to the present invention, particularly the thin-film solar cell 14 described above, is not limited and can be used for any purpose. For example, the solar cells according to the embodiment include solar cells for building materials, solar cells for automobiles, solar cells for interiors, solar cells for railways, solar cells for ships, solar cells for airplanes, solar cells for spacecraft, and solar cells for home appliances. It can be used as a battery, a solar cell for a mobile phone, or a solar cell for a toy.

The solar cell according to the present invention, particularly the thin-film solar cell 14 described above, may be used as it is, or may be used as a component of the solar cell module. For example, as shown in FIG. 5, a solar cell module 13 having the solar cell according to the present invention, particularly the above-mentioned thin-film solar cell 14 on a base material 12, is manufactured, and the solar cell module 13 is installed at a place of use. Can be used. As the base material 12, a well-known technique can be used. For example, as the material of the base material 12, the materials described in International Publication No. 2013/171517, International Publication No. 2013/180230, JP-A-2012-191194, etc. Can be used. For example, when a plate material for building materials is used as the base material 12, by providing the thin film solar cell 14 on the surface of the plate material, the solar cell panel for the outer wall of the building can be manufactured as the solar cell module 13.

Hereinafter, embodiments of the present invention will be described with reference to examples. However, the present invention is not limited to the following examples as long as the gist of the present invention is not exceeded.

[Example 1]
(Preparation of active layer coating solution)
Lead (II) iodide (211 mg), lead (II) chloride (127 mg) and methylammonium iodide (CH ₃ NH ₃ I, 291 mg) were weighed into vials so that the molar ratio was 1: 1: 4. Sulfamic acid (13 mol% with respect to the total amount of lead compounds (total amount of lead (II) iodide and lead (II) chloride)) and N, N-dimethylformamide (2 mL) were added to obtain a mixed solution. The pKa value of the methylammonium ion was 10.6. Next, the obtained mixed solution was heated and stirred at 70 ° C. for 2 hours. Then, the obtained solution was filtered through a polytetrafluoroethylene (PTFE) filter (pore size 0.2 μm) to prepare an active layer coating solution. The total concentration of lead (II) iodide, lead (II) chloride and methylammonium iodide in the obtained active layer coating solution was 25% by mass. By using the active layer coating solution thus prepared, a perovskite semiconductor compound (484 mg) composed of lead (II) iodide, lead (II) chloride, and methylammonium iodide having a molar ratio of 1: 1: 2 and It was considered that a semiconductor layer containing sulfamic acid could be formed.

(Manufacturing of photoelectric conversion element)
For a glass substrate (manufactured by Geomatec) equipped with a patterned indium tin oxide (ITO) transparent conductive film, a cleaning agent (manufactured by Yokohama Yushi Kogyo Co., Ltd., cleaning agent for precision glass substrate Semiclean M-LO, 15 mL) is used. Ultrasonic cleaning with ultrapure water, ultrasonic cleaning with ultrapure water, drying with nitrogen blow, and UV-ozone treatment were performed.

Next, a poly (3,4-ethylenedioxythiophene) poly (styrene sulfonic acid) dispersion (PEDOT: PSS, manufactured by Heleus) was filtered through a motorcycle al (pore size 0.45 μm), and then at room temperature, the above. A hole extraction layer having a thickness of about 35 nm was formed on the substrate by spin coating at a speed of 3000 rpm. The obtained substrate was heated at 120 ° C. for 30 minutes.

Next, the substrate was introduced into a glove box and heat-treated at 115 ° C. for 20 minutes in a nitrogen atmosphere. After cooling, the active layer coating liquid (130 μL) was spin-coated on the substrate at a speed of 4000 rpm to form a layer having a thickness of about 120 nm, and further heat-annealed on a hot plate at 100 ° C. for 25 minutes. As described above, the active layer was formed.

Next, an amorphous fluororesin polymer solution CYTOP (manufactured by Asahi Glass Co., Ltd., adjusted to 0.4% by mass, 0.05 mL) was added onto the active layer under a rotation of 6000 rpm to form an insulator layer. The thickness of the insulator layer was 5 nm.

The characteristics of CYTOP are volume resistivity:> 10 ¹⁷ Ωcm (JIS K6911), relative permittivity: 2.0 to 2.1 (100 Hz to 1 MHz, room temperature, JEC-6150), refractive index: 1.34 ( JIS K7142, 25 ° C ~), water contact angle: 110 °, glass transition temperature: 108 ° C. The visible light transmittance of the 200 μm thick CYTOP film is 95%. Further, the water vapor transmittance of the 100 μm thick CYTOP film was 0.2 g / m ² (24 hours).

Next, _{a solution of phenyl C 61} butyrate methyl ester (PCBM, manufactured by Frontier Carbon Co., Ltd., 20 mg) dissolved in chlorobenzene (1 mL) was filtered through a polytetrafluoroethylene (PTFE) filter (pore size 0.2 μm). The obtained solution (100 μL) was spin-coated on the active layer at a speed of 1000 rpm to form an electron extraction layer having a thickness of about 80 nm.

Next, a methanol solution (0.2% by mass, 0.1 mL) of polyethyleneimine ethoxylate (PEIE) was added onto the electron extraction layer under a rotation of 6000 rpm to tune the work function to a thickness of about 10 nm. A layer was formed.

Next, a silver film having a thickness of about 150 nm was deposited on the work function tuning layer using a patterning mask by a resistance heating type vacuum deposition method to form an electrode. In this way, a 25 × 30 mm square photoelectric conversion element was manufactured.

[Example 2]
A photoelectric conversion element was produced in the same manner as in Example 1 except that the amount of sulfamic acid used in preparing the active layer coating solution was 17 mol% with respect to the total amount of lead compounds.

[Example 3]
A photoelectric conversion element was produced in the same manner as in Example 1 except that the amount of sulfamic acid used in preparing the active layer coating solution was 26 mol% with respect to the total amount of lead compounds.

[Example 4]
A photoelectric conversion element was produced in the same manner as in Example 1 except that the amount of sulfamic acid used in preparing the active layer coating liquid was 34 mol% with respect to the total amount of lead compounds.

[Example 5]
A photoelectric conversion element was produced in the same manner as in Example 1 except that the amount of sulfamic acid used in preparing the active layer coating solution was 43 mol% with respect to the total amount of lead compounds.

[Example 6]
A photoelectric conversion element was produced in the same manner as in Example 1 except that tartaric acid (8.3 mol% with respect to the total amount of lead compounds) was used instead of sulfamic acid when preparing the active layer coating solution.

[Example 7]
A photoelectric conversion element was produced in the same manner as in Example 1 except that L-alcorbic acid (17.6 mol% with respect to the total amount of lead compounds) was used instead of sulfamic acid when preparing the active layer coating solution. ..

[Example 8]
A photoelectric conversion element was produced in the same manner as in Example 1 except that malic acid (9.3 mol% with respect to the total amount of lead compounds) was used instead of sulfamic acid when preparing the active layer coating solution.

[Example 9]
A photoelectric conversion element was produced in the same manner as in Example 1 except that citric acid (16.1 mol% with respect to the total amount of lead compounds) was used instead of sulfamic acid when preparing the active layer coating solution.

[Example 10]
A photoelectric conversion element was produced in the same manner as in Example 1 except that citric acid (21.6 mol% with respect to the total amount of lead compounds) was used instead of sulfamic acid when preparing the active layer coating solution.

[Example 11]
A photoelectric conversion element was produced in the same manner as in Example 1 except that citric acid (35.2 mol% with respect to the layer amount of the lead compound) was used instead of sulfamic acid when preparing the active layer coating liquid. ..

[Comparative Example 1]
A photoelectric conversion element was produced in the same manner as in Example 1 except that sulfamic acid was not added when the active layer coating solution was prepared.

[Comparative Example 2]
A photoelectric conversion element was produced in the same manner as in Example 1 except that an aqueous solution of hydrogen iodide (54.0 mol% aqueous solution, 200 μL) was added instead of sulfamic acid when preparing the active layer coating solution. Considering that the boiling point of hydroiodic acid is about −35 ° C., it is considered that hydroiodic acid volatilized during heating and did not remain in the active layer after film formation. ..

[Evaluation of photoelectric conversion element]
A 1 mm square metal mask was attached to the photoelectric conversion elements obtained in Examples 1 to 11 and Comparative Examples 1 and 2, and the current-voltage characteristics between the ITO electrode and the silver electrode were measured. A source meter (2400 type manufactured by Keithley Co., Ltd.) was used for the measurement, and a solar simulator with an ^{air mass (AM) of 1.5 G and an irradiance of 100 mW / cm 2 was used as the irradiation light source.} From this measurement result, the open circuit voltage Voc (V), the short-circuit current density Jsc (mA / cm ² ), the shape factor FF, and the photoelectric conversion efficiency PCE (%) were calculated. Table 1 shows these values calculated based on the measurement results immediately after the photoelectric conversion element was manufactured.

表１において、ｐＫａは、添加した化合物（中性化合物）からの１段階目の電離のｐＫａ値を表す。

In Table 1, pKa represents the pKa value of the first stage ionization from the added compound (neutral compound).

Here, the open circuit voltage Voc is ^{the voltage value when the current value = 0 (mA / cm 2} ), and the short-circuit current density Jsc is the current density when the voltage value = 0 (V). The scherrer FF is a factor representing the internal resistance, and is expressed by the following equation where the maximum output is Pmax.
FF = Pmax / (Voc × Jsc)
Further, the photoelectric conversion efficiency PCE is given by the following equation, where the incident energy is Pin.
PCE = (Pmax / Pin) x 100
= (Voc x Jsc x FF / Pin) x 100

As shown in Table 1, in Examples 1 to 11 in which the additive was added to the active layer, it was found that the short-circuit current density Jsc and the photoelectric conversion efficiency PCE were improved.

When the active layer obtained in Example 11 was measured with a scanning electron microscope, it was confirmed that it was larger than the crystal size of the active layer obtained in Comparative Example 1. Further, it was confirmed by two-dimensional X-ray diffraction that the active layer of Example 11 had a high crystal orientation. As a result, it is considered that high conversion efficiency is obtained by adding the additive. Moreover, when the active layer of Example 11 was measured by TOF-SIMS, it was confirmed that the additives were biased to one side. From this result, it is considered that the additive contributes during the crystal growth.

1 Weather-resistant protective film 2 Ultraviolet cut film 3, 9 Gas barrier film 4, 8 Getter film 5, 7 Encapsulant 6 Solar cell element 10 Back sheet 12 Base material 13 Solar cell module 14 Thin-film solar cell 31 Base material 32 Anode 33 Hole injection layer 34 Hole transport layer 35 Light emitting layer 36 Electron transport layer 37 Electron injection layer 38 Cathode 39 Electroelectric light emitting element 51 Semiconductor layer 52 Insulation layer 53, 54 Source electrode and drain electrode 55 Gate electrode 56 Base material 100 Photoelectric conversion Element 101 Anode 102 Hole extraction layer 103 Active layer 104 Insulation layer 105 Electron extraction layer 106 Work function tuning layer 107 Cathode 108 Base material

Claims (7)

A semiconductor device having a pair of electrodes and a semiconductor layer arranged between the pair of electrodes, wherein the semiconductor layer is a monovalent cation containing an additive, a divalent cation, and a monovalent cation. It is a perovskite semiconductor layer composed of anions, and the additive has a pKa value lower than the pKa value of the monovalent cation, and the pKa value is 0.99 or more and 4.17 or less (however, the pKa value is A semiconductor device, characterized in that it is a compound ( except when it is 3.09). The semiconductor device according to claim 1, wherein the compound is a compound having a carboxyl group, a sulfonic acid group, a phosphoric acid group or an carboxylic acid anhydride group. The semiconductor device according to claim 1 or 2, wherein the compound has a boiling point of 100 ° C. or higher. The semiconductor device according to any one of claims 1 to 3, wherein the compound has a melting point of 100 ° C. or higher. The semiconductor device according to any one of claims 1 to 4, wherein the semiconductor device is a photoelectric conversion element. A solar cell comprising the semiconductor device according to claim 5. A solar cell module including the solar cell according to claim 6.

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