JP3249619B2 - Solar cell - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solar cell.

[0002]

2. Description of the Related Art Conventionally, typical solar cells of this type include single crystal silicon (c-Si), amorphous silicon (a-Si), and cadmium (C-Si).
Compound semiconductors using materials such as d) and arsenic (As) are known.

[0003]

However, the single-crystal silicon (c-Si) solar cell has a problem that the manufacturing process is complicated and the cost is high, and the amorphous silicon (a-Si) solar cell is problematic. Although the manufacturing process is relatively simple and inexpensive, there is a problem that the photovoltaic power tends to change with time. Furthermore, since cadmium (Cd) or the like is used for compound semiconductors, there is a problem that the material has toxicity. Accordingly, it is an object of the present invention to provide a solar cell which is free from problems such as toxicity in terms of material, hardly deteriorates with time, and is easy to obtain a material.

[0004]

Means for Solving the Problems] characterizing feature of the solar cell of the present invention for achieving the above object, according to claim 1
As halogen homo pn junction with the semiconductor portion of the p-type characteristics by doping Ru is formed, that they are hetero pn junction or a hetero ip junction configured fullerenes material mainly containing C ₆₀ In . Also achieve the above purpose
The feature configuration of the solar cell according to the present invention for forming
2, as described in, Fuller mainly containing C ₆₀
P-type characteristics formed by doping halogenated materials with lens
A semiconductor section, or fullerenes material mainly containing C ₆₀
Pn junction having an n-type semiconductor portion composed of
The point is that they are combined. Furthermore, in the above-mentioned characteristic configuration,
And the halogen is iodine.
It is preferred that Also, to achieve the above purpose
The feature configuration of the solar cell according to the present invention is described in claim 4.
As shown, indium oxide doped with tin on the surface side
Transparent electrode (5), which is an ITO thin film having n-type or n-type
Hula mainly composed of purified C ₆₀ as a semiconductor portion of the i-type
-Lens thin film (4), as p-type semiconductor part (30)
A back electrode (6) made of a p-type silicon layer and an Au thin film is
Hetero stacked from the light receiving side in the order described and electrically connected
pn junction or hetero ip junction
You.

[0005]

[Action] In other words, fullerene mainly composed of pure C ₆₀
Materials exhibit i-type or n-type properties, and
When doped with elemental halogen, etc., it has p-type characteristics
A semiconductor can be obtained. These things have recently been
It is a new finding by the light people,
Therefore, good results have been obtained in the solar cell of the present application.
(The IV characteristics of the solar cell of the example are shown in FIG. 4). Based on these findings, the solar cell of the present application has at least C
Fullerenes based on ₆₀ are doped with halogen
And a p-type semiconductor that forms a pn junction and an ip junction
It is those employed by, further, n-type, i-type semiconductor portion
Adopting fullerenes material mainly composed of C ₆₀ as
You can also . Alternatively, oxide oxide doped with tin on the surface side
A transparent electrode (5), which is an ITO thin film containing nd;
composed mainly of purified C ₆₀ as a semiconductor portion of the n-type or i-type
Fullerene thin film (4), p-type semiconductor part (3
0) as a p-type silicon layer,
The poles (6) are laminated from the light-receiving side in the order described and electrically connected.
A continuous hetero pn junction or hetero ip junction configuration
Can be As an example, the operation of a solar cell in the case of a pn junction will be described. Light incident from the light receiving side reaches each semiconductor unit. The light incident on these semiconductor parts is
Absorbed to produce photogenerated charge. A pair of semiconductor portions constituting the solar cell is configured to have a pn junction structure. Due to internal electrolysis of the pn junction, positive photo-generated charges are collected on the p-type side, and negative photo-generated charges are collected on the n-type side. And are taken out of the solar cell from the back electrode and the transparent electrode, respectively.

[0006]

Therefore, in the solar cell of the present invention, C
Fullerenes based on ₆₀ are doped with halogen
Because fullerenes material mainly composed of the ones and C ₆₀ is used, temporal property changes such as those found in amorphous silicon (a-Si), can be avoided to the toxicity problems, is the material available It was possible to obtain a solar cell that was easy to manufacture and could be formed by easy operations such as vapor deposition during production.

[0007]

EXAMPLES solar cell 1, fullerenes consisting mainly of C ₆₀
P-type semiconductor formed by doping halogen-like materials
Part or the p-type semiconductor portion and the C ₆₀ fullerenes material than formed n-type composed mainly of homo pn junction with the i-type semiconductor portion, is of the hetero pn junction or ip bonding configuration. That is, a pair of a p-type semiconductor portion, an n-type semiconductor portion or an i-type semiconductor portion is provided (hereinafter, one of the semiconductor portions is referred to as a first semiconductor portion 2a, and the first semiconductor portion 2a
The semiconductor portion is referred to as a second semiconductor portion 2b), these one 2a (2b) having different conductivity with respect to the C ₆₀
Doping halogen into the fullerenes material as the main component
P-type semiconductor formed (hereinafter, halogen doped C ₆₀ semi
Body). On the other hand, 2b (2a) has C ₆₀
Or i-type composed of fullerenes whose main component is
Child adopted n-type semiconductor (hereinafter, referred to as C ₆₀ Semiconductor)
Can be . When it is desired to obtain an i-type or n-type C ₆₀ semiconductor, purified C ₆₀ can be used as it is by an operation such as vapor deposition, and in the case of a p-type semiconductor,
A material doped with a halogen such as iodine is used.
Further, the solar cell 1 is configured by including a transparent electrode 5 having a light-transmitting property and a back electrode 6 as electrodes.

FIGS. 1 (first configuration example), FIG. 2 (second configuration example), and FIG. 3 (third configuration example) show a configuration example of a solar cell having a pn junction configuration.
A description will be given based on a configuration example). FIGS. 1 and 2 show the case where the support 3 is used. The first semiconductor portion 2a and the second semiconductor portion 2b have a configuration of a homo-pn junction using a halogen-doped C ₆₀ semiconductor and a C ₆₀ semiconductor. Part 2
halogen doped C ₆₀ using semiconductor or C ₆₀ semiconductor <br/> in a (2b), halogen doped C ₆₀ semiconductor on the other 2b (2a)
And optionally hetero pn junction using a C ₆₀ other than the semiconductor semiconductor, can be configured either. FIG. 3 shows a bulk p-type halogen-doped C ₆₀ half as a support.
This is the case where a semiconductor portion 30 other than a conductor or an n-type C ₆₀ semiconductor is used, and a p-type halogen-doped C ₆₀ semiconductor or
Forms a thin film 4 of C ₆₀ semiconductor shows a case of a configuration for a hetero pn junction.

The transparent electrode 5 provided on the light receiving side will be described. As the transparent electrode 5, the semiconductor portion 2a which is in contact
A conductive material capable of forming an ohmic electrode with (2b, 4) is used and has a light transmitting property. For example,
Among metals such as Pt, Al, Au, Ni, and Ag and alloys thereof, a substance capable of forming an ohmic junction with the target semiconductor portion 2a (2b, 4) is used. A thin film of about several tens of nanometers is obtained.
As such a transparent electrode, an electrically conductive oxide such as SnO ₂ or Sn-doped In ₂ O ₃ or ZnO can be used.

The back electrode 6 provided on the side opposite to the light receiving side will be described. Also in the case of the back electrode 6,
A conductive material that can form an ohmic electrode with the semiconductor portion 2a (2b, 30) that is in contact is used, and translucency is not required. Among metals such as Pt, Al, Au, Ni, and Ag and alloys thereof, a substance capable of forming an ohmic junction is used.

Finally, each configuration example of the support 3 that determines the pivotal configuration of the solar cell will be described. In the case of the first configuration example, the support 3 may be conductive or electrically insulating. As the conductive support material, for example, stainless steel,
Examples include metals such as aluminum and alloys thereof.
Examples of the electrically insulating support material include inorganic substances such as glass and ceramics, and synthetic resin films such as polyethylene terephthalate. The shape of the support 3 may be either a smooth surface or an uneven surface, and may be a flat surface or a curved surface such as a cylinder. In the case of the second configuration example, the support 3 may be conductive or electrically insulating as in the case of the first configuration example. However, since light is incident from the support side, the support 3 is transparent. Must have Examples of the electrically insulating support material include a light-transmitting inorganic material such as glass and a light-transmitting synthetic resin film such as polyethylene terephthalate. In the case of the third configuration example, one conductive semiconductor portion 30 is configured as a bulk, which has a function as a support. As an example, a semiconductor such as silicon is used as the support. In this case, the semiconductor acts as a support while
Also works as a photoactive layer.

The above is the schematic configuration of the solar cell 1 shown in the present application. Hereinafter, the configuration and characteristics of the solar cell of the third configuration example (shown in FIG. 3) will be described more specifically. 1 Configuration of solar cell This is a C ₆₀ thin film 4 acting as an n-type or i-type semiconductor part.
And a p-type silicon layer serving as a p-type semiconductor portion 30 as a support. As the transparent electrode 5, an ITO thin film of indium oxide doped with tin is provided on the front surface side, and a back electrode 6 made of an Au thin film is provided on the back surface side. Therefore, the solar cell 1 has a so-called hetero-junction configuration, and receives light from the transparent electrode on the upper side of the drawing to function as a battery. Detailed Configuration p-type silicon substrate 30 0.5 mm thick C ₆₀ thin film 4 thickness 1 [mu] m 99.9% purity forming method vacuum deposition to about 10 ^-5 Torr 400 ° C. Each electrode 5,6 thickness 300~400Å in a vacuum atmosphere of

2 Characteristics of Solar Cell FIG. 4 shows the IV characteristics of the solar cell 1 having the above-described configuration, and FIG. 5 shows the conductivity characteristics. As is clear from the IV characteristics, an electromotive force of about 0.3 V was obtained under irradiation with a 300 W Xe lamp. Furthermore, from 1.5 to 1.5
The portion at 2.0 eV shows negative characteristics, indicating that there is a band gap.

[Other Embodiments] In the above-mentioned embodiments, the expression of fullerene semiconductors containing C ₆₀ as a main component is employed. Among them, C ₆₀ , C ₇₀ C ₇₆ C _{82 and the} like are contained in addition to C _60. The Rukoto.

In the claims, reference numerals are provided for convenience of comparison with the drawings, but the present invention is not limited to the configuration shown in the accompanying drawings.

[Brief description of the drawings]

FIG. 1 is a diagram showing a structure of a first configuration example of a solar cell.

FIG. 2 is a diagram showing a structure of a second configuration example of the solar cell;

FIG. 3 is a diagram showing a structure of a third configuration example of the solar cell;

FIG. 4 is a diagram showing IV characteristics of a solar cell.

FIG. 5 is a diagram showing conductivity characteristics of a solar cell.

[Explanation of symbols]

 4 Thin film 30 p-type silicon

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-335614 (JP, A) Noboru Akuzawa, Takayuki Terai, Chemical Modification of Fullerene, Carbon, Japan, No. 154, p 251-261 (58) Field (Int.Cl. ⁷ , DB name) H01L 31/04-31/078 JICST file (JOIS)

Claims (4)

(57) [Claims] The method according to claim 1] C ₆₀ to fullerene material mainly
Homo pn junction having a semiconductor portion of the p-type characteristics that will be formed by doping halogen, hetero pn junction or hetero ip
The solar cell of contact Go構 formed. 2. A fullerene material containing C ₆₀ as a main component.
Semiconductor part with p-type characteristics formed by doping halogen
And a fullerene material containing C ₆₀ as a main component
Of a homo-pn junction structure having a semiconductor portion having n-type characteristics
Positive battery. 3. The method according to claim 1, wherein said halogen is iodine.
Is the solar cell according to 2. 4. Indium oxide doped with tin on the surface side
Electrode (5), which is an ITO thin film with a
Ku is off mainly composed of purified C ₆₀ as a semiconductor portion of the i-type
As a thin film of laren (4), as a p-type semiconductor part (30)
Back electrode made of p-type silicon layer and Au thin film (6)
From the light-receiving side to the
A solar cell having a terrorist pn junction or hetero ip junction configuration .