JP2009059782A - Photoelectric conversion device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrolyte containing type photoelectric conversion device which attains sufficient photoelectric conversion efficiency. <P>SOLUTION: The photoelectric conversion device includes a first conductor 3, a second conductor 9 provided opposite the first conductor 3 at an interval, a non-monocrystalline semiconductor 4 provided on a principal surface of the first conductor 3 on the side opposed to the second conductor 9, an electrolyte 7 provided between the second conductor 9 and non-monocrystalline semiconductor 4, and a sealing member 6 provided between the first conductor 3 and second conductor 9 and coming into contact with an outer circumferential side surface of the non-monocrystalline semiconductor 4 to seal the electrolyte. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a photoelectric conversion device excellent in photoelectric conversion efficiency.

  Photovoltaic conversion devices such as solar cells are clean power generation technologies that do not emit carbon dioxide and harmful exhaust gas, which cause global warming, and continue to generate power as long as there is light, and have been actively developed in recent years. ing.

In particular, an amorphous thin film such as amorphous silicon can be manufactured because the thickness can be reduced, and a module having a large size can be manufactured even at a low cost. Attention has been focused on a photoelectric conversion device having the above (for example, see Patent Document 1).
JP-A-6-140648

  At present, for photoelectric conversion devices having an amorphous thin film, it is considered to further improve the photoelectric conversion efficiency by further providing an electrolyte composed of a fluid such as a liquid and sufficiently transporting charges. However, the desired photoelectric conversion efficiency was insufficient.

  Accordingly, an object of the present invention is to provide an electrolyte-containing photoelectric conversion device that achieves sufficient photoelectric conversion efficiency.

  The present invention opposes the first conductor having translucency, the second conductor provided so as to face the first conductor at an interval, and the second conductor. A non-single crystal semiconductor provided on a main surface of the first conductor on the side, an electrolyte provided between the second conductor and the non-single crystal semiconductor, and the first conductor And a sealing member which is provided between the second conductor and is in contact with an outer peripheral side surface of the non-single-crystal semiconductor and seals the electrolyte.

  It is preferable that the sealing member continuously contacts the non-single crystal semiconductor from the outer peripheral side surface to a part of the main surface of the non-single crystal semiconductor on the side facing the second conductor.

  It is preferable that the sealing member continuously contacts the non-single crystal semiconductor from the outer peripheral side surface to the main surface of the main surface of the first conductor.

  The electrolyte is preferably a liquid or gel electrolyte.

  The non-single-crystal semiconductor preferably has a pin structure including an i-type non-single-crystal semiconductor.

  It is preferable to further include a first catalyst layer provided on the non-single-crystal semiconductor on the side facing the electrolyte and promoting charge transfer.

  It is preferable to further include a second catalyst layer provided on the second conductor on the side facing the electrolyte and promoting charge transfer.

  It is preferable to further include an oxide semiconductor provided on the second conductor on the side facing the electrolyte, and a photoexciter attached to the surface of the oxide semiconductor.

  The sealing member is preferably one kind selected from the group consisting of polyethylene resin, polypropylene resin, epoxy resin, fluororesin and silicone resin.

  The sealing member is preferably glass or ceramics.

  According to the photoelectric conversion device of the present invention, by providing the sealing member that contacts the outer peripheral side surface of the non-single crystal semiconductor, contact between the first conductor and the electrolyte is suppressed, Since generation of reverse electron transfer due to electrons is reduced, high photoelectric conversion efficiency can be realized.

  It is preferable that the sealing member continuously contacts the non-single crystal semiconductor from the outer peripheral side surface to a part of the main surface of the non-single crystal semiconductor on the side facing the second conductor. With this configuration, since the side surface portion of the non-single-crystal semiconductor is embedded on the sealing member side, even if the volume of the sealing member or the like changes due to a temperature condition change with respect to the photoelectric conversion device, the first conductor Since the contact between the electrolyte and the electrolyte is sufficiently suppressed and the occurrence of reverse electron transfer due to electrons in the electrolyte is reduced, higher photoelectric conversion efficiency can be realized.

  It is preferable that the sealing member continuously contacts from the outer peripheral side surface to the main surface of the first conductor. With this configuration, since the first conductor is contacted and covered by the sealing member, contact between the electrolyte and the sealing member is sufficiently suppressed, and reverse electron transfer due to electrons in the electrolyte occurs. Therefore, higher photoelectric conversion efficiency can be realized.

  The electrolyte is preferably a liquid or gel electrolyte. With this configuration, since the electrolyte is excellent in charge transport characteristics, sufficient photoelectric conversion efficiency can be realized.

  The semiconductor layer preferably has a pin structure including an i-type non-single-crystal semiconductor. With this configuration, sufficient photoelectric conversion efficiency can be realized by sufficiently sending electrons generated from the non-single-crystal semiconductor to the electrolyte.

  The photoelectric conversion device of the present invention preferably further includes the first catalyst layer on the non-single crystal semiconductor on the side facing the electrolyte. Since the first catalyst layer lowers the overvoltage and sufficiently secures an ohmic junction between the electrolyte and the non-single-crystal semiconductor, sufficient photoelectric conversion efficiency can be realized.

  The photoelectric conversion device of the present invention preferably further includes the second catalyst layer on the second conductor on the side facing the electrolyte. Since the second catalyst layer reduces the resistance between the electrolyte and the second conductor, sufficient carrier exchange between the electrolyte and the second conductor is possible.

  The photoelectric conversion device of the present invention may further include an oxide semiconductor provided on the second conductor on the side facing the electrolyte, and a photoexciter attached to the surface of the oxide semiconductor. preferable. With this configuration, the photoelectric conversion device has improved long wavelength sensitivity and can absorb a wide wavelength region, so that photoelectric conversion can be performed in a wide wavelength region, and sufficient photoelectric conversion efficiency can be realized.

  The sealing member is preferably one kind selected from the group consisting of polyethylene resin, polypropylene resin, epoxy resin, fluororesin and silicone resin. The sealing member is preferably glass or ceramics. Since these are resistant to the electrolyte and have high electrical insulation, the contact between the first conductor and the electrolyte can be sufficiently suppressed as a sealing member.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the photoelectric conversion devices described in these drawings. In addition, an actual photoelectric conversion device does not follow the vertical and horizontal scales of the photoelectric conversion device in the drawing.

  One embodiment of a photoelectric conversion device of the present invention is shown in FIG.

  The photoelectric conversion device of the present invention in FIG. 1 includes a first conductor 3, a second conductor 9, a non-single crystal semiconductor 4, an electrolyte 7, and a sealing member 6. . Each configuration will be described below.

<Photoelectric Conversion Device in FIG. 1>
(First conductor)
The first conductor 3 is a light-transmitting conductor.

The first conductor 3 is preferably one that transmits a wavelength component (approximately 300 to 700 nm) absorbed by the non-single-crystal semiconductor 4. For example, a tin-doped indium oxide layer (ITO layer), an impurity-doped indium oxide layer ( In ₂ O ₃ layer), fluorine-doped tin dioxide layer (SnO ₂ : F layer), impurity-doped zinc oxide layer (ZnO layer), and the like. These are formed by, for example, a low temperature growth sputtering method, a low temperature spray pyrolysis method, a thermal CVD method, a vacuum deposition method, an ion plating method, a dip coating method, a sol-gel method, or the like.

(Second conductor)
The second conductor 9 is a conductor provided to face the first conductor 3 with a gap. The interval between the second conductor 9 and the first conductor 3 is designed such that a non-single crystal semiconductor 4, an electrolyte 7, and a sealing member 6 described later are interposed therebetween.

Examples of the second conductor 9 include metal sheets such as titanium, stainless steel, aluminum, silver, copper, and nickel, resin sheets impregnated with fine lines made of carbon, metal fine particles, metals, and the like, conductive resins, ITO, SnO. ₂ : An oxide conductive film made of F (fluorine-doped SnO ₂ ), ZnO: Al (Al-doped ZnO), or the like. Since the resistance is particularly low, the metal sheet is preferable as the second conductor 9 because it is excellent.

  When the second conductor 9 is composed of a metal having light reflectivity such as silver or aluminum, the second conductor 9 is provided with excellent light reflectivity. Can be reused.

Even if the second conductor 9 is a translucent conductor (SnO ₂ : Blue plate glass with F (F-doped SnO ₂ ) film, etc.), light is reflected on the back surface of the second conductor 9. A light-reflecting property may be imparted by forming a sheet or film made of conductive aluminum or silver.

  Examples of the second conductor 9 include a laminated structure such as a titanium layer / ITO layer / titanium layer, a laminated structure such as a Ti layer / Ag layer / Ti layer with an adhesion layer, and a silver film. , Vacuum deposition, ion plating, sputtering, electrolytic deposition, and the like.

  The thickness of the second conductor 9 is preferably 0.001 to 10 μm, and more preferably 0.05 to 2 μm.

(Non-single crystal semiconductor)
The non-single crystal semiconductor 4 is provided on the main surface of the first conductor 3 on the side facing the second conductor 9. Here, the non-single crystal includes amorphous or polycrystalline.

  Examples of the amorphous semiconductor 4 include amorphous silicon carbide and amorphous silicon nitride.

As the amorphous semiconductor 4, silicon is mainly used. Besides silicon, III-V semiconductors such as gallium nitride and gallium arsenide, Cu (Ga, In) Se ₂ , Cu ₂ O, Cu (Ga , In) Se ₂ , and semiconductor materials such as CuAlSe ₂ .

  As the non-single-crystal semiconductor 4, in particular, a first conductive semiconductor layer 4a (p-type semiconductor layer), an intrinsic semiconductor layer 4b (i-type semiconductor layer), and a second conductive semiconductor layer 4c (n-type semiconductor layer) are stacked. The pin structure is preferable. In the case of a pn structure having no i-type semiconductor layer, most of electrons and holes are dispersed in the semiconductor layer, whereas in the pin structure, most of electrons and holes generated by light are i-type. Since it is generated in the semiconductor layer, it can be immediately extracted as a photo-generated current.

  The non-single crystal semiconductor 4 is manufactured by continuous deposition using a plasma CVD method, a catalytic CVD method, a chemical vapor deposition method, or the like. In particular, when the plasma CVD method and the catalytic CVD method are combined, the hydrogen content can be increased, the photodegradation of the non-single crystal semiconductor 4 can be suppressed, and the reliability can be improved.

  As a method for manufacturing the amorphous semiconductor 4, chemical vapor deposition is suitable because it can be continuously deposited under each film forming condition.

  For example, when a p-type a-Si: H layer is formed as the first conductive semiconductor layer 4a, the thickness of the p-type a-Si: H layer is preferably 5 to 30 nm. If it is thinner than 5 nm, the open circuit voltage tends to decrease. Moreover, when thicker than 30 nm, there exists a tendency for a short circuit bulb to fall.

  Further, when an i-type a-Si: H layer is formed as the intrinsic semiconductor layer 4b, the thickness of the i-type a-Si: H layer is preferably 50 to 800 nm. If it is thinner than 50 nm, the amount of electricity converted based on light is small, and the short-circuit current tends to be small. On the other hand, if the thickness is greater than 800 nm, the generated electric field tends to be small, and the collection efficiency of the generated carriers tends to decrease.

  Furthermore, when the n-type a-Si: H layer is formed as the second conductive semiconductor layer 4c, the thickness of the n-type a-Si: H layer is preferably 5 to 50 nm. If it is thinner than 5 nm, the open circuit voltage tends to decrease. On the other hand, if it is thicker than 50 nm, the series resistance of the photoelectric conversion device tends to increase.

(Electrolytes)
The electrolyte 7 is provided between the second conductor 9 and the non-single crystal semiconductor 4 and has a function of transporting charges.

  Examples of the electrolyte 7 include a liquid electrolyte, a gel electrolyte, and a solid electrolyte. Especially, since it is excellent in a charge transport characteristic, it is preferable that it is a liquid or gel electrolyte.

  Liquid electrolytes exist as redox systems in reversibly oxidized and reduced states such as iodine (I) ions / triiodine ions (I), bromine ions, iron (II) / iron (III) ions, etc. A pair of substances.

  The liquid electrolyte is prepared by further mixing the substance with an organic solvent such as ethylene carbonate, propylene carbonate, dimethyl sulfoxide, acetonitrile, ionic liquid, γ-butyrolactone, methoxypropionitrile, and the like. For example, a mixture prepared by mixing tetrapropylammonium iodide, lithium iodide, iodine, quaternary ammonium salt, Li salt, or the like can be used.

  Gel electrolytes are roughly classified into chemical gels and physical gels. The chemical gel is a gel formed by a chemical bond by a crosslinking reaction or the like, and the physical gel is gelled near room temperature due to physical interaction. As a specific gel electrolyte, a host polymer such as polyethylene oxide, polyacrylonitrile, polyvinylidene fluoride, polyvinyl alcohol, polyacrylic acid, or polyacrylamide is mixed into acetonitrile, ethylene carbonate, propylene carbonate or a mixture thereof. A gel electrolyte polymerized in this manner is preferred.

  The gel electrolyte is formed using a low-viscosity precursor, and then gelled by causing a two-dimensional or three-dimensional crosslinking reaction by means of heating, ultraviolet irradiation, electron beam irradiation, or the like. be able to.

  The thickness of the electrolyte 7 is preferably about 0.01 to 500 μm. When the thickness is less than 0.1 μm, the positive electrode side and the counter electrode side tend to contact and short-circuit. When the thickness exceeds 500 μm, the photoelectric conversion efficiency is likely to be lowered due to an increase in the electrolyte 7 as a resistance component, and when the electrolyte 7 is in a liquid state, a sealing defect due to an increase in the liquid portion is likely to occur.

(Sealing member)
The sealing member 6 is provided between the first conductor 3 and the second conductor 9 and seals the electrolyte 7.

  The sealing member 6 is preferably an organic material selected from the group consisting of polyethylene resin, polypropylene resin, epoxy resin, fluororesin or silicone resin. Moreover, it is preferable that the sealing member 6 is an inorganic material of glass or ceramics. Since these materials are resistant to liquids and have high electrical insulation, the sealing member 6 made of these materials has the first conductivity even if the electrolyte 7 is liquid, for example. Contact between the body 3 and the electrolyte 7 can be sufficiently suppressed.

  When the sealing member 6 is an organic material, the raw material is a film or a liquid.

  When the raw material of the sealing member 6 is a film, the sealing member 6 cuts the opening in a window frame shape with respect to the film-like raw material, and then heats the film-like raw material between the electrodes at 100 to 300 ° C. It is fabricated so as to be bonded between the first conductor 3 and the second conductor 9 by pressure bonding. At this time, the sealing member 6 is bonded so as to prevent contact between the electrolyte 7 and the first conductor 3.

  Further, when the raw material of the sealing member 6 is liquid, the sealing member 6 applies the liquid raw material between the first conductor 3 and the second conductor 9 by screen printing or a dispenser. After the bonding, thermal polymerization bonding or photopolymerization bonding is performed so that the first conductor 3 and the second conductor 9 are bonded. At this time, the sealing member 6 is bonded so as to prevent contact between the electrolyte 7 and the first conductor 3.

  Here, in order to compare with the photoelectric conversion device of the present invention, FIG. 4 shows a photoelectric conversion device related to the present invention. In FIG. 1, the sealing member 6 is in contact with the outer side surface 4 d of the non-single crystal semiconductor 4, whereas in FIG. 4, the sealing member 26 is not in contact with the outer side surface 24 d of the non-single crystal semiconductor 24. The difference is that they are separated.

  In the case of FIG. 4, the sealing member 26 is thermocompression bonded between the electrodes at 100 to 300 ° C. after the opening is cut into a window frame shape. Since the sealing member 26 is cut larger than the non-single crystal semiconductor 24 when being bonded between the first conductor 23 and the second conductor 29, Since a gap exists between the outer side surface 24d and the sealing member 26, and the electrolyte 27 enters the gap, the first conductor 23 and the electrolyte 27 come into contact with each other, and reverse electron transfer occurs, resulting in photoelectric conversion efficiency. Decreases.

  On the other hand, in the case of FIG. 1, since the sealing member 6 is in contact with the outer side surface 4 d of the non-single crystal semiconductor 4, the contact between the first conductor 3 and the electrolyte 7 is suppressed and reverse electron transfer is performed. Generation | occurrence | production can be reduced and a photoelectric conversion efficiency can be improved.

  The sealing member 6 is in contact with the outer peripheral side surface 4 d of the non-single crystal semiconductor 4, and is further in contact with the non-single crystal semiconductor 4 continuously from the outer peripheral side surface 4 d to a part of the main surface of the non-single crystal semiconductor 4. It is preferable to do. Here, it demonstrates below based on FIG. 2 which is an enlarged view of the A section in FIG.

  In FIG. 2, a part 4 e of the main surface of the non-single crystal semiconductor 4 is in contact with the sealing member 6. By continuously contacting the sealing member 6 from the outer peripheral side surface 4d to a part 4e of the main surface, the contact between the first conductor 3 and the electrolyte 7 is sufficiently suppressed to reduce the occurrence of reverse electron transfer. The photoelectric conversion efficiency can be improved. Here, the “part” of the main surface 4 e of the non-single crystal semiconductor 4 indicates an outer peripheral portion of the main surface of the non-single crystal semiconductor 4. The “main surface” of the main surface 4 e of the non-single-crystal semiconductor 4 refers to the main surface on the side facing the second conductor 9.

  The sealing member 6 is preferably in contact with the outer peripheral side surface 4 d of the non-single crystal semiconductor 4 and continuously from the outer peripheral side surface 4 d to the main surface of the first conductor 3. In FIG. 2, the main surface of the first conductor 3 is in contact with the sealing member 6. By continuously contacting the sealing member 6 from the outer peripheral side surface 4d to the main surface 3, the contact between the first conductor 3 and the electrolyte 7 is sufficiently suppressed, the occurrence of reverse electron transfer is reduced, and photoelectric conversion is performed. Efficiency can be improved.

  The thickness of the sealing member 6 is preferably 0.06 to 1000 μm. If it is less than 0.06 μm, it is thinner than the non-single-crystal semiconductor 4, so that it is difficult to seal the electrolyte 7. On the other hand, when the thickness exceeds 1000 μm, the electrolyte 7 covered with the sealing member 6 also becomes thick, so that the internal resistance increases and the photoelectric conversion efficiency of the device tends to decrease. The thickness of the sealing member 6 refers to the length of the sealing member 6 from the first conductor 3 to the second conductor 9.

  The sealing member 6 can be brought into contact with the outer side surface 4d of the non-single crystal semiconductor 4 in a wide area by being heated and pressure-bonded to the adhesive material under conditions of 100 ° C. to 300 ° C.

  In addition, the sealing member 6 is manufactured by applying pressure to the adhesive material by applying heat, so that the sealing member 6 not only contacts the outer side surface 4d of the non-single crystal semiconductor 4, but also from the outer peripheral side surface 4d to the second conductor 9. Can be continuously contacted up to a part (4e in FIG. 2) of the main surface of the non-single-crystal semiconductor 4 on the side facing the surface.

(First catalyst layer and second catalyst layer)
The photoelectric conversion device of the present invention preferably includes the first catalyst layer 5 and the second catalyst layer 8 in addition to the above-described configuration. Here, the first catalyst layer 5 is provided on the non-single crystal semiconductor 4 on the side facing the electrolyte 7, lowers the overvoltage, secures an ohmic junction between the electrolyte 7 and the non-single crystal semiconductor 4, and performs charge transfer. It has something to promote. The second catalyst layer 8 is provided on the second conductor 9 and has a function of reducing overvoltage and promoting charge transfer between the electrolyte 7 and the second conductor 9.

  The overvoltage refers to a large voltage that is first applied to operate the photoelectric conversion device 1.

  Specific examples of the first catalyst layer 5 and the second catalyst layer 8 include metals such as Pt (platinum) and Pd (palladium). The thickness of the first catalyst layer 5 and the second catalyst layer 8 is preferably 0.5 to 20 nm. If it is less than 0.5 nm, the space between the islands of the catalyst layer is too far away, and it becomes difficult to obtain a catalytic effect. On the other hand, if it exceeds 20 nm, the amount of transmitted light decreases. The first catalyst layer 5 and the second catalyst layer 8 are formed by a sputtering method or the like. However, in order to form a plurality of island shapes, as described above, the formation of the extremely thin thickness is limited. Can be realized.

  Since the first catalyst layer 5 and the second catalyst layer 8 have an effect of reducing overvoltage with iodine as an electrolyte, it is preferable that they are provided together. If only the first catalyst layer 5 or only the second catalyst layer 8 is used as the catalyst layer, the overvoltage in the electron transfer at the interface increases in the layer without the catalyst layer, so that the resistance tends to increase. .

(Translucent substrate)
The light-transmitting substrate 2 is a substrate on which the first conductor 3 can be formed on the surface and light can be incident on the non-single crystal semiconductor 4. Here, “translucency” means transmitting a wavelength component (approximately 300 to 700 nm) absorbed by the non-single-crystal semiconductor 4.

  The translucent substrate 2 is anti-glare, heat-shielding, heat resistance, low contamination, antibacterial, anti-fungal, design, high workability, anti-glare / wear resistance, snow sliding, anti-static, By imparting far-infrared radiation, acid resistance, corrosion resistance, environmental compatibility, and the like, the reliability and merchantability of the photoelectric conversion device can be further improved.

  As a material of the translucent substrate 2, a resin sheet such as a fluororesin, a silicone polyester resin, a high weather resistance polyester resin, a polyvinyl chloride resin, PET (polyethylene terephthalate), PEN (polyethylene naphthalate), polyimide, or polycarbonate, or Examples thereof include inorganic sheets such as white plate glass, soda glass, borosilicate glass, and ceramics.

  The thickness of the translucent substrate 2 is preferably 0.1 μm to 6 mm, and more preferably 1 μm to 4 mm.

(Counter electrode substrate)
The counter electrode side substrate 10 refers to a substrate on which the second conductor 9 can be formed.

  Examples of the counter electrode side substrate 10 include resin materials such as PET (polyethylene terephthalate), PEN (polyethylene naphthalate), polyimide, and polycarbonate, inorganic materials such as blue plate glass, soda glass, borosilicate glass, and ceramics, or conductive resin. Examples include materials and organic-inorganic hybrid materials.

  The thickness of the counter electrode side substrate 10 is preferably 0.01 mm to 5 mm.

<Photoelectric Conversion Device in FIG. 3>
Next, the photoelectric conversion device illustrated in FIG. 3 will be described. 3 includes the first conductor 3, the second conductor 9, the non-single crystal semiconductor 4, the electrolyte 7, and the sealing member 6, and the oxide semiconductor 11 and the photoexciter 12. It also has. Hereinafter, the oxide semiconductor 11 and the photoexciter 12 will be described.

(Oxide semiconductor)
The oxide semiconductor 11 is provided on the second conductor 9 on the side facing the electrolyte 7.

  As the oxide semiconductor 11, a porous n-type oxide semiconductor made of titanium dioxide or the like is preferably used.

  The oxide semiconductor 11 is usually made of titanium dioxide or the like (n-type metal oxide semiconductor), and preferably a plurality of granular or linear bodies (needle, tube, column, etc.). It is good to have a set of At this time, it is preferable that an average particle diameter or an average wire diameter is 5-500 nm, and it is more preferable that it is 10-200 nm. There is a tendency that miniaturization of the material with an average particle diameter or an average wire diameter of less than 5 nm tends to be difficult, and when the average particle diameter exceeds 500 nm, the junction area becomes small and the photocurrent tends to become extremely small.

As the oxide semiconductor 11, titanium oxide (TiO ₂ ) is optimal, and as other materials, titanium (Ti), zinc (Zn), tin (Sn), niobium (Nb), indium (In), yttrium (Y), lanthanum (La), zirconium (Zr), tantalum (Ta), hafnium (Hf), strontium (Sr), barium (Ba), calcium (Ca), vanadium (V), tungsten (W), etc. Non-metallic elements such as nitrogen (N), carbon (C), fluorine (F), sulfur (S), chlorine (Cl), phosphorus (P), etc. One or more of these may be contained. Titanium oxide or the like is preferable because it has an electron energy band gap in the range of 2 to 5 eV, which is larger than the energy of visible light. The oxide semiconductor 11 is preferably an n-type semiconductor whose conduction band is lower than the conduction band of the dye at the electron energy level.

  The porosity of the oxide semiconductor 11 is preferably 20 to 80%, and more preferably 40 to 60%. When the oxide semiconductor 11 has such a porosity, the surface area of the light working electrode can be increased by 1000 times or more, and light absorption, power generation, and electron conduction can be performed efficiently.

  The thickness of the oxide semiconductor 11 is preferably 0.1 to 50 μm, and more preferably 1 to 20 μm. If the thickness is less than 0.1 μm, the photoelectric conversion action is remarkably reduced and is not suitable for practical use. If the thickness exceeds 50 μm, light transmission becomes difficult.

  When the oxide semiconductor 11 is made of titanium dioxide, the manufacturing method thereof is as follows.

First, acetylacetone is added to TiO ₂ anatase powder, and then kneaded with deionized water to prepare a titanium dioxide paste stabilized with a surfactant. Next, the prepared paste is applied onto the second conductor 9 at a constant speed by a doctor blade method, and is 300 ° C. to 600 ° C., preferably 400 ° C. to 500 ° C. in air, for 10 minutes to 60 minutes. The porous oxide semiconductor 11 is preferably formed by treating for 20 minutes to 40 minutes.

(Photo-exciter)
In the present invention, the photoexciter 12 is attached to the surface of the oxide semiconductor 11.

  As the photoexciter 12, the photocurrent efficiency (incident photon to current efficiency; IPCE) with respect to incident light, the so-called sensitivity, extends to the longer wavelength side than the absorption wavelength of the electrolyte 7 or the absorption wavelength of the amorphous semiconductor 4. Those having characteristics are preferred. In particular, since it is rarely absorbed by the electrolyte 7 or the like, it is particularly effective that the absorption peak has a peak sensitivity at a wavelength longer than about 700 nm.

  As such a photoexciter 12, a bis-type squarylium cyanine dye is effective because the peak wavelength of IPCE is close to 800 nm. Azurenium salt compounds, squalinic acid derivatives, triallylpyrazoline, hydrazone derivatives, biphenyldiamine derivatives, tri-p-tolylamine (TPTA), trisazo pigments, τ-type non-metals with high sensitivity (IPCE) at wavelengths of 700 nm or more Photoexciters 12 such as phthalocyanine, titanyl phthalocyanine, squarylium cyanine, black dye, coumarin, β-diketonate, Re complex, Os complex, Ni complex, Pd complex, Pt complex, phthalocyanine derivative and porphyrin derivative are preferred.

  As a method for adsorbing the photoexciter 12 to the porous oxide semiconductor 11, a method of immersing the second conductive layer body 9 on which the oxide semiconductor 11 is formed in a solution in which the photoexciter 12 is dissolved may be mentioned. In this case, the temperature of the solution and the atmosphere is not particularly limited, and may be room temperature under atmospheric pressure, for example. Further, the immersion time can be appropriately adjusted depending on the photoexciter 12, the type of solvent, the concentration of the solution, and the like. Thereby, the photoexciter 12 can be adsorbed to the porous oxide semiconductor 11.

Examples of the solvent used for dissolving the photoexciter 12 include a mixture of one or more alcohols such as ethanol, ketones such as acetone, ethers such as diethyl ether, nitrogen compounds such as acetonitrile, and the like. . In this case, the concentration of the photoexciter 12 in the solution is preferably about 5 × 10 ⁻⁵ to 2 × 10 ⁻³ mol / l (l: liter (1000 cm ³ )).

In addition, the photoexciter 12 is composed of a single molecule, an ultrathin film (thickness having a thickness of nanometer order in which the thickness affects the band gap), a fine particle, and an ultrafine particle (in the order of nanometer in which the particle diameter affects the band gap) (Refers to small particles), and at least one kind of quantum dots is preferable. In particular, when the photoexciter 12 is made of an ultrafine semiconductor, the band gap is no longer a value inherent to the material, but depends on the size. As a result, even if the material has a considerably small band gap (1 eV or less), the band gap can be increased by nano-sizing, so that the absorption wavelength can be selected and the sensitivity can be easily lengthened. Examples of the ultrafine semiconductor include CdS, CdSe, PbS, PbSe, CdTe, Bi ₂ S ₃ , InP, Si, Ge, CIGS (CuInGaSe), CIS (CuInS ₂ ), FeS ₂ , Ag ₂ S, Sb ₂ S _3. , ZnS, Fe ₂ O _{3 and the} like.

<Photovoltaic generator>
The photoelectric conversion device of the present invention can be used as power generation means. And the said photoelectric conversion apparatus is installed in the roof and wall surface of a building by using with the load supplied with the electric power generated by the said photoelectric conversion apparatus like an inverter apparatus, an electric motor, a lighting apparatus, etc. It can be used as a solar cell or the like.

  EXAMPLES The present invention will be described in detail below based on examples, but the present invention is not limited to these examples.

<Example>
The photoelectric conversion device of FIG. 1 was produced as follows.

A glass substrate (size: 2 cm × size) on which one SnO ₂ : F layer (fluorine-doped SnO ₂ layer, sheet resistance: 10Ω / □ (square), thickness 1 μm) as the first conductor 3 is formed on one main surface. 2 cm, thickness 2 mm) was used as the translucent substrate 2.

  By using a plasma CVD apparatus in a vacuum, a p-type a-Si layer (hereinafter referred to as p-type a-Si: H layer) and an i-type a-Si layer (hereinafter referred to as i-type a-) doped with hydrogen, respectively. A non-single-crystal semiconductor 4 was formed on the first conductor 3 in succession by an Si: H layer and an n-type a-Si layer (hereinafter, n-type a-Si: H layer) successively. In FIG. 1, the first conductive semiconductor layer 4a is a p-type a-Si: H layer, the intrinsic semiconductor layer 4b is an i-type a-Si: H layer, and the second conductive semiconductor layer 4c is an n-type a. Corresponds to each of the Si: H layers.

Specifically, the p-type a-Si: H layer uses SiH ₄ gas, H ₂ gas, and B ₂ H ₆ gas (diluted to 500 ppm with H ₂ ) as source gases, and the gas flow rate of the plasma CVD apparatus is changed. They were deposited on the first conductor 3 by setting them to 3 sccm, 10 sccm, and 2 sccm, respectively (p-type a-Si: H layer thickness 90 mm (9 nm)).

Further, the i-type a-Si: H layer specifically uses SiH ₄ gas and H ₂ gas as source gases, and the gas flow rate of the plasma CVD apparatus is set to 30 sccm and 80 sccm, respectively. -Deposited on Si: H layer (i-type a-Si: H layer thickness 1700 mm (170 nm)).

Further, the n-type a-Si: H layer specifically uses SiH ₄ gas, H ₂ gas, and PH ₃ gas (those diluted to 1000 ppm with H ₂ ) as source gases, and the gas flow rate of the plasma CVD apparatus. Was set to 3 sccm, 30 sccm, and 6 sccm, respectively, to be deposited on the i-type a-Si: H layer (the thickness of the n-type a-Si: H layer was 100 Å (10 nm)).

  Note that the temperature during the formation of the p-type a-Si: H layer, the i-type a-Si: H layer, and the n-type a-Si: H layer was 220 ° C.

  A Pt (platinum) layer as the catalyst layer 5 was formed on the n-type a-Si: H layer by sputtering so as to have a thickness of 5 nm. At this time, since the Pt layer was very thin, it was formed into an island shape.

  By using a thermoplastic adhesive that is a film-like sealing member 6 (manufactured by DuPont: trade name “Bynel 4164”) and applying pressure to the adhesive material under conditions of 250 ° C., The outer peripheral portion 4e of the main surface on the side facing the second conductor 9 among the main surfaces of one conductor 3 was bonded and hermetically sealed. At this time, not only the main surface of the first conductor 3 and the main surface of the second conductor 9, but also the outer side surface (4d in FIG. 2) of the non-single crystal semiconductor 4 and the second conductor 9 A thermoplastic adhesive was provided so as to hermetically seal the outer peripheral portion (4e in FIG. 2) of the main surface of the non-single crystal semiconductor 4 on the opposite side. In addition, the space | interval (equivalent to the thickness of the electrolyte 7) between the translucent board | substrate 2 and the counter electrode side board | substrate 10 was 30 micrometers.

Thereafter, a liquid electrolyte containing iodine (I ₂ ), lithium iodide (LiI), and tetrabutylpyridine is injected as an electrolyte 7 from a through-hole formed in the light-transmitting substrate 12 in advance, thereby producing a photoelectric conversion device. (FIG. 1) was produced.

<Comparative example>
Although the photoelectric conversion device of FIG. 4 was manufactured, the sealing member 26 is separated from the outer side surface so that these photoelectric conversion devices do not come into contact with the outer side surface (24d in FIG. 4) of the non-single crystal semiconductor 24. It was produced by the same method as in the example except for the above. In addition, the sealing member 26 cuts the opening part of the film-like sealing member 26 into a window frame shape, and then at the time of thermocompression bonding between the first electrode 23 and the second electrode 29 at 100 to 300 ° C., The sealing member 26 is provided by cutting larger than the non-single crystal semiconductor 24.

About the photoelectric conversion apparatus with an area of 1 cm ² of an Example and a comparative example, the light of AM1.5 solar simulator was irradiated and the photoelectric characteristic was measured.

The photoelectric conversion device of the example had a short-circuit photocurrent density of 10.14 mA cm ⁻² , an open electromotive force of 895 mV, a locality factor of 0.581, and a conversion efficiency of 5.28%.

In contrast, the photoelectric conversion device of the comparative example had a short-circuit photocurrent density of 10.12 mA cm ⁻² , an open electromotive force of 678 mV, a locality factor of 0.467, and a conversion efficiency of 3.20%.

  Comparing the measured values of the example and the comparative example, the open electromotive force and the locality factor were improved by 32% and 24%, respectively, in the example compared to the comparative example, and as a result, the conversion efficiency was improved by 65% as a percentage. . The reason why the photoelectric conversion efficiency is improved by 65% is that the sealing member 6 is in contact with the entire outer peripheral side surface of the non-single crystal semiconductor 4 to prevent the electron transfer from the electrolyte 7 to the first conductor 3. Thus, the photoelectric conversion efficiency is considered to be improved with respect to the comparative example.

It is sectional drawing which shows an example of the photoelectric conversion apparatus of this invention. It is an enlarged view of the part of A in FIG. It is sectional drawing which shows an example of the photoelectric conversion apparatus of this invention. It is sectional drawing which shows an example of an electrolyte containing type photoelectric conversion apparatus.

Explanation of symbols

1: Incident light 2: Translucent substrate 3: First conductor 4: Non-single crystal semiconductor 4a: First conductivity type semiconductor layer 4b: Intrinsic semiconductor layer 4c: Second conductivity type semiconductor layer 4d: Non-single crystal semiconductor 4 outer side surface 4e: outer peripheral portion 5 of the main surface of the non-single crystal semiconductor 4 facing the second conductor 9: first catalyst layer 6: sealing member 7: electrolyte 8: second catalyst layer 9: Second conductor 10: Counter electrode substrate 11: Oxide semiconductor 12: Photoexciter

Claims (10)

A first conductor having translucency;
A second conductor provided to face the first conductor with a gap;
A non-single crystal semiconductor provided on the main surface of the first conductor on the side facing the second conductor;
An electrolyte provided between the second conductor and the non-single-crystal semiconductor;
A sealing member that is provided between the first conductor and the second conductor, contacts an outer peripheral side surface of the non-single crystal semiconductor, and seals the electrolyte;
A photoelectric conversion device comprising:   The said sealing member contacts the said non-single-crystal semiconductor continuously from the said outer peripheral side surface to a part of main surface of the said non-single-crystal semiconductor on the side facing the said 2nd conductor. Photoelectric conversion device.   3. The photoelectric conversion device according to claim 1, wherein the sealing member continuously contacts the non-single crystal semiconductor from the outer peripheral side surface to the main surface of the main surface of the first conductor.   The photoelectric conversion device according to claim 1, wherein the electrolyte is a liquid or gel electrolyte.   The photoelectric conversion device according to claim 1, wherein the non-single-crystal semiconductor has a pin structure including an i-type non-single-crystal semiconductor.   6. The photoelectric conversion device according to claim 1, further comprising a first catalyst layer provided on the non-single-crystal semiconductor on the side facing the electrolyte and promoting charge transfer.   The photoelectric conversion device according to claim 1, further comprising a second catalyst layer that is provided on the second conductor on the side facing the electrolyte and promotes charge transfer. An oxide semiconductor provided on the second conductor on the side facing the electrolyte;
A photoexciter attached to the surface of the oxide semiconductor;
The photoelectric conversion device according to claim 1, further comprising:   The photoelectric conversion device according to claim 1, wherein the sealing member is one selected from the group consisting of polyethylene resin, polypropylene resin, epoxy resin, fluororesin, and silicone resin.   The photoelectric conversion device according to claim 1, wherein the sealing member is glass or ceramics.

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