JP5127261B2 - Manufacturing method of photoelectric conversion module - Google Patents

Description

  The present invention relates to a photoelectric conversion module in which a plurality of dye-sensitized photoelectric conversion elements such as solar cells and light receiving elements excellent in photoelectric conversion efficiency and reliability are formed.

  Conventionally, a dye-sensitized solar cell, which is a type of photoelectric conversion device, does not require a vacuum device for its production, so it is considered to be a low-cost, low-environmental load-type solar cell, and is actively researched and developed. Has been done.

  In Patent Document 1, a photoactive electrode substrate in which a photosensitizer complex in which a ruthenium complex dye or the like is attached as a photosensitizer to titanium dioxide coated on a conductive glass substrate, and conductive glass An electrolyte containing a counter electrode substrate in which a platinum or carbon counter electrode layer is formed on a substrate, a porous titanium oxide layer and a counter electrode layer facing each other, and bonding both substrates together, and an iodine / iodide redox pair between these substrates A dye-sensitized solar cell having a structure in which a solution is injected and filled through a through hole formed in a counter electrode substrate and the through hole of the counter electrode substrate is closed is described.

  Patent Document 2 describes a dye-sensitized solar cell in which the periphery of a first substrate provided with a semiconductor and a second substrate provided with a conductive film are sealed with glass frit. As a result, the leakage of the electrolytic solution or volatilization is reduced by improving the sealing performance, the electrolytic solution can be sufficiently retained, and the photoelectric conversion efficiency (hereinafter also referred to as conversion efficiency) stable for a long period of time. ) Can be obtained.

The large-area dye-sensitized solar cell described in Patent Document 3 is made of titanium, platinum, gold, etc., and uses a metal grid in which an infinite number of openings are formed. The metal grid is made of titanium oxide or the like. This is a structure in which an oxide semiconductor sintered product is integrally bonded to form a photoelectrode. With this configuration, the specific resistance of the metal grid is significantly lower than that of a conductive thin film such as ITO or FTO having a large specific resistance, and a low resistance can be realized.
JP 2002-512729 A JP 2001-185244 A JP 2003-123855 A

  However, as in the configurations of Patent Documents 1 and 2, in the cell structure in which two substrates of the photoactive electrode substrate and the counter electrode substrate are bonded, the surface of the porous titanium oxide layer adsorbing the sensitizing dye and the surface of the counter electrode It was difficult to manufacture the gap filled with the electrolyte between them with a narrow and constant gap, and it was difficult to manufacture a product with high conversion efficiency and stability and high reliability.

  In addition, when the substrate size is increased as in the large area dye-sensitized solar cell of Patent Document 3, a metal grid having a low resistance is introduced as compared with conductive thin films such as ITO and FTO having a large specific resistance. Series resistance becomes a problem.

  Furthermore, when used outdoors, it is necessary to have a module configuration in which the voltage is increased by connecting them in series, and the conventional technology cannot achieve both improvement in conversion efficiency and ensuring reliability.

  Accordingly, the present invention has been completed in view of the problems in the conventional technology described above, and an object thereof is to electrically connect the photoelectric conversion elements in a photoelectric conversion module in which a plurality of photoelectric conversion elements are arranged. Providing a dye-sensitized photoelectric conversion module that realizes reliable connection by ensuring the corrosion resistance of the conductor to the electrolyte, ensuring both high reliability and improved conversion efficiency To do.

  In the method for producing a photoelectric conversion module of the present invention, a first conductive layer as one electrode on which a porous semiconductor layer carrying a sensitizing dye is formed, and the porous semiconductor layer are disposed opposite to each other. A photoelectric conversion module manufacturing method in which an electrolyte is disposed between the second conductive layer as a counter electrode to form a photoelectric conversion element, and a plurality of the photoelectric conversion elements are arranged to manufacture a photoelectric conversion module. A conductive paste containing glass frit for electrically connecting the first conductive layer of the photoelectric conversion element and the second conductive layer of the photoelectric conversion element adjacent to the first conductive layer; The conductive material is applied to at least one of the two conductive layers, and then a glass paste is applied around the conductive paste, and then the conductive paste and the glass paste are irradiated with laser light and fired. And forming a fine glass layer.

  In the method for producing a photoelectric conversion module of the present invention, preferably, after the photoelectric conversion element is formed, a glass paste is applied around the photoelectric conversion element, and then the glass paste is irradiated with laser light and fired. A glass sealing layer is formed by.

  In the method for producing a photoelectric conversion module of the present invention, a first conductive layer as one electrode on which a porous semiconductor layer carrying a sensitizing dye is formed, and the porous semiconductor layer are arranged opposite to each other. It is a method for manufacturing a photoelectric conversion module, in which an electrolyte is arranged between a second conductive layer as a counter electrode to form a photoelectric conversion element, and a plurality of photoelectric conversion elements are arranged to manufacture a photoelectric conversion module, Conductive paste containing glass frit for electrically connecting the first conductive layer of the photoelectric conversion element and the second conductive layer of the adjacent photoelectric conversion element is used as at least one of the first and second conductive layers. Next, a glass paste is applied around the conductive paste, and then the conductive paste and the glass paste are irradiated with laser light and fired to form a conductor and a glass layer. conversion Since the entire joule is not sealed by increasing the temperature, the sensitizing dye and the electrolyte are formed by heat treatment or the like when the counter electrode layer is laminated or sealed after the sensitizing dye is adsorbed and the electrolyte is injected as in the past. Deterioration can be prevented, resulting in an increase in conversion efficiency.

  In the method for producing a photoelectric conversion module of the present invention, preferably, after the photoelectric conversion element is formed, a glass paste is applied around the photoelectric conversion element, and then the glass paste is irradiated with laser light and fired. By forming the stop layer, the glass paste is welded with laser light, so the sensitizing dye adsorbing part can be adsorbed to the vicinity of the sealing part in advance, and the utilization efficiency of incident light can be improved. .

  Embodiments of the photoelectric conversion module and the manufacturing method thereof according to the present invention will be described below in detail with reference to FIGS. In addition, in each figure, the same code | symbol is attached | subjected to the same member. Further, the first conductive layer 3 in FIG. 2 is drawn with a half length so that the inside of the photoelectric conversion module can be easily understood.

  A cross-sectional view of the photoelectric conversion module of the present invention is shown in FIG. In the photoelectric conversion module 1 of FIG. 1, a first conductive layer 3 composed of a transparent conductive layer or the like and a porous semiconductor layer 5 adsorbing (supporting) a sensitizing dye 4 are laminated on a substrate 2, and a counter electrode side substrate 9. A second conductive layer 7 as a counter electrode layer is formed thereon, and the substrate 2 and the counter electrode side substrate 9 are opposed to each other so that the porous semiconductor layer 5 and the second conductive layer 7 are opposed to each other. The electrolyte 6 is disposed therebetween, and the outer peripheral portions of the substrate 2 and the counter electrode side substrate 9 are sealed with a glass sealing layer 10.

  Further, inside the substrate 2 and the counter electrode side substrate 9, a set (photoelectric conversion element unit) of the first conductive layer 3, the porous semiconductor layer 5, the electrolyte 6, and the second conductive layer 7 is provided in the plane direction. A plurality of pairs are formed, and for adjacent pairs, a glass frit in which the first conductive layer 3 of the photoelectric conversion element and the second conductive layer 7 of the adjacent photoelectric conversion element are covered with the glass layer 12 is used. It is connected by the conductor 8 containing.

  The method for producing the photoelectric conversion module 1 of the present invention is such that the first conductive layer 3 as one electrode on which the porous semiconductor layer 5 carrying the sensitizing dye 4 is formed and the porous semiconductor layer 5 are opposed to each other. The photoelectric conversion element 1 is manufactured by disposing an electrolyte 6 between the second conductive layer 7 as a counter electrode disposed to form a photoelectric conversion element, and arranging a plurality of photoelectric conversion elements. A method for manufacturing a module, comprising: a conductive paste containing a glass frit for electrically connecting a first conductive layer 3 of a photoelectric conversion element and a second conductive layer 7 of an adjacent photoelectric conversion element; By applying to at least one of the first and second conductive layers 3 and 7, then applying a glass paste around the conductive paste, and then irradiating the conductive paste and the glass paste with laser light and firing. , Conductor 8 and glass layer It is configured to form a 2.

  Specifically, the photoelectric conversion module 1 in FIG. 1 forms a laminate in which a first conductive layer 3 and a porous semiconductor layer 5 are integrally laminated in this order on a substrate 2, and then this The laminate is immersed in the sensitizing dye 4 solution to adsorb the sensitizing dye 4 to the porous semiconductor layer 5, and the first conductive layer 3 and the second conductive layer 7 on the counter electrode side substrate 9 are connected to the conductor. 8, the counter electrode side substrate 9 is disposed on the laminated body through the region of the electrolyte 6, and then the peripheral portion of the substrate 2 and the counter electrode side substrate 9 is bonded by the glass sealing layer 10. At the same time, a glass sealing layer 10 is formed around the conductor 8, and a solution of the electrolyte 6 is injected from a through hole formed in the glass sealing layer 10 to form the porous semiconductor layer 5. Manufactured by infiltration.

  Next, each element which comprises the photoelectric conversion module 1 mentioned above is demonstrated in detail.

<First conductive layer>
The substrate 2 and the first conductive layer 3 may be formed by forming a metal layer or a transparent conductive layer on an insulating substrate. When the substrate 2 has translucency, the porous semiconductor layer 5 can be formed on the substrate 2 which is a light working side electrode substrate, and the porous semiconductor layer 5 can be arranged on the light incident side, so that the conversion efficiency is high. It becomes. Moreover, when the board | substrate 2 and the counter electrode side board | substrate 9 have translucency, since light can enter from any surface of the main surface of the photoelectric conversion module 1, it makes light incident from both main surface sides, and converts Efficiency can be increased.

  The material of the substrate 2 is glass such as white plate glass, soda glass, borosilicate glass, inorganic materials such as ceramics, resin such as polyethylene terephthalate (PET), polycarbonate (PC), acrylic, polyethylene naphthalate (PEN), polyimide, etc. Materials, organic-inorganic hybrid materials, etc. are preferable.

  As the translucent substrate 2, at least in the wavelength range of visible light, for example, in the case of a white glass substrate having a thickness of 0.7 mm, it has a light transmittance of 92% or more in the wavelength range of 400 to 1100 nm. In the case of a polyethylene terephthalate (PET) or polycarbonate (PC) substrate, the light transmittance is about 90% for visible light, and the preferred light transmittance is at least 90% light transmission in the visible light wavelength range. Any substrate having a rate can be used. As the material of the light-transmitting substrate 2, glass such as white plate glass, soda glass, borosilicate glass, inorganic materials such as ceramics, polyethylene terephthalate (PET), polycarbonate (PC), acrylic, polyethylene naphthalate (PEN) , Resin materials such as polyimide, and organic-inorganic hybrid materials are preferable.

As the first conductive layer 3, a transparent conductive layer of metal oxide doped with fluorine or metal can be used. Among them, a fluorine-doped tin dioxide film (SnO ₂ : F film) formed by a thermal CVD method has heat resistance and is particularly good. In addition, a tin-doped indium oxide film (ITO film) or an impurity-doped indium oxide film (In ₂ O ₃ film) formed by a low-temperature growth sputtering method or a low-temperature spray pyrolysis method is preferable. In addition, an impurity-doped zinc oxide film (ZnO film) formed by a solution growth method is preferable. Further, these transparent conductive layers may be laminated and used in various combinations. Further, the transparent conductive layer may be a laminate of a Ti layer, an ITO layer, and a Ti layer sequentially, and becomes a laminated film with improved adhesion and corrosion resistance.

  The thickness of the transparent conductive layer is 0.001 to 10 μm, preferably 0.05 to 2.0 μm from the viewpoint of high conductivity and high light transmittance. When the thickness is less than 0.001 μm, the resistance of the transparent conductive layer increases. When the thickness exceeds 10 μm, the light transmittance of the transparent conductive layer decreases.

  Other film forming methods for the transparent conductive layer include a vacuum deposition method, an ion plating method, a dip coating method, a sol-gel method, and the like. By these film forming methods, it is preferable to form irregularities in the order of the wavelength of incident light on the surface of the transparent conductive layer, and a light confinement effect can be imparted.

Therefore, as the first conductive layer 3, a thin film made of gold, palladium, titanium, aluminum, stainless steel, silver, copper, nickel, or the like formed by vacuum deposition or sputtering is formed by vacuum deposition or sputtering. What you did is good. Alternatively, a transparent conductive layer (impurity-doped metal oxide layer) such as a SnO ₂ : F layer or the like may be formed on the substrate 2 made of metal to prevent corrosion by the electrolyte 6.

<Porous semiconductor layer>
As shown in FIG. 1, a porous semiconductor layer 5 is formed on the substrate 2 and the first conductive layer 3. The material and composition of the porous semiconductor layer 5 is optimally titanium oxide (TiO ₂ ), and other materials include titanium (Ti), zinc (Zn), tin (Sn), and niobium (Nb). , Indium (In), yttrium (Y), lanthanum (La), zirconium (Zr), tantalum (Ta), hafnium (Hf), strontium (Sr), barium (Ba), calcium (Ca), vanadium (V) Metal oxide semiconductors of at least one metal element such as tungsten (W) are preferable, and nitrogen (N), carbon (C), fluorine (F), sulfur (S), chlorine (Cl), phosphorus ( One or more non-metallic elements such as P) 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 porous semiconductor layer 5 is preferably an n-type semiconductor whose conduction band is lower than that of the sensitizing dye 4 in the electron energy level.

  The porous semiconductor layer 5 is made of titanium dioxide or the like, and has a large number of fine pores (having a pore diameter of preferably about 10 to 40 nm, with a peak conversion efficiency at 22 nm). It may be a porous n-type oxide semiconductor layer or the like. When the pore diameter of the porous semiconductor layer 5 is less than 10 nm, the penetration and adsorption of the sensitizing dye 4 are inhibited, and a sufficient amount of adsorption of the sensitizing dye 4 cannot be obtained, and the diffusion of the electrolyte 6 is hindered. Therefore, the diffusion resistance increases, so that the conversion efficiency is lowered. If the thickness exceeds 40 nm, the specific surface area of the porous semiconductor layer 5 decreases, so that the amount of adsorption of the sensitizing dye 4 must be increased, and if the thickness is increased too much, light is transmitted. The sensitizing dye 4 cannot absorb light, and the movement distance of the charge injected into the porous semiconductor layer 5 is increased, resulting in an increase in loss due to charge recombination, and the electrolyte 6 Since the diffusion distance also increases and the diffusion resistance increases, the conversion efficiency also decreases.

  The porous semiconductor layer 5 is a porous body that is a granular body, or a linear body such as a needle-like body, a tubular body, or a columnar body, or a collection of these various linear bodies. Thereby, the surface area which adsorb | sucks the sensitizing dye 4 increases, and conversion efficiency can be improved. The porous semiconductor layer 5 is preferably a porous body having a porosity of 20 to 80%, more preferably 40 to 60%. The surface area as the light working electrode layer can be increased 1000 times or more by making it porous, and light absorption, photoelectric conversion, and electronic conduction can be performed efficiently.

  The porosity of the porous semiconductor layer 5 is obtained by obtaining an isothermal adsorption curve of the sample by a nitrogen gas adsorption method using a gas adsorption measuring device, and using a BJH (Barrett-Joyner-Halenda) method or a CI (Chemical Ionization) method. , DH (Dollimore-Heal) method or the like can be used to determine the pore volume and obtain it from the particle density of the sample.

  The shape of the porous semiconductor layer 5 is preferably a shape having a large surface area and a small electric resistance, and is preferably composed of fine particles or fine linear bodies, for example. The average particle diameter or average wire diameter is preferably 5 to 500 nm, and more preferably 10 to 200 nm. Here, if the lower limit of the average particle diameter or the average wire diameter of 5 to 500 nm is less than this, the material cannot be miniaturized, and if the upper limit exceeds this, the junction area is reduced and the photocurrent is significantly reduced. It depends.

  Moreover, by making the porous semiconductor layer 5 into a porous body, the surface of the dye-sensitized photoelectric conversion body formed by adsorbing the sensitizing dye 4 to the porous semiconductor layer 5 becomes uneven, resulting in a light confinement effect, The conversion efficiency can be further increased.

  The thickness of the porous semiconductor layer 5 is preferably 0.1 to 50 μm, more preferably 1 to 20 μm. Here, the lower limit value at 0.1 to 50 μm is not suitable for practical use when the thickness is smaller than this, and the upper limit value is not suitable for practical use. This is because light is not incident.

When the porous semiconductor layer 5 is made of titanium oxide, it is formed as follows. First, acetylacetone is added to TiO ₂ anatase powder, and then kneaded with deionized water to prepare a titanium oxide paste stabilized with a surfactant. The prepared paste is applied at a constant speed onto the first conductive layer 3 on the substrate 2 by a doctor blade method, a bar coating method, or the like, and is 300 to 600 ° C. in air, preferably 400 to 500 ° C. The porous semiconductor layer 5 is formed by heat treatment for 60 minutes, preferably 20 to 40 minutes. This method is simple and preferable.

As a low temperature growth method of the porous semiconductor layer 5, an electrodeposition method, an electrophoretic electrodeposition method, a hydrothermal synthesis method or the like is preferable. As a post-treatment for improving electron transport properties, a microwave treatment or a CVD method is used. A UV treatment such as plasma treatment or thermal catalyst treatment is preferable. The porous semiconductor layer 5 formed by the low temperature growth method is preferably composed of a porous ZnO layer formed by the electrodeposition method, a porous TiO ₂ layer formed by the electrophoretic electrodeposition method, and the like.

Further, the surface of the porous body of the porous semiconductor layer 5 may be treated with TiCl ₄ treatment, that is, immersed in a TiCl ₄ solution for 10 hours, washed with water, and fired at 450 ° C. for 30 minutes. The conversion efficiency is improved.

  In addition, an ultrathin dense layer of an n-type oxide semiconductor may be inserted between the porous semiconductor layer 5 and the substrate 2, and the reverse current can be suppressed, so that the conversion efficiency is increased.

  The porous semiconductor layer 5 is preferably composed of a sintered body of oxide semiconductor fine particles, and the average particle diameter of the oxide semiconductor fine particles is preferably gradually increased in the thickness direction from the substrate 2 side. The semiconductor layer 5 is preferably composed of a two-layer laminate in which the average particle diameter of the oxide semiconductor fine particles is different. Specifically, the oxide semiconductor fine particles having a small average particle diameter are used on the substrate 2 side, and the oxide semiconductor fine particles (scattering particles) having a large average particle diameter are used on the second conductive layer 7 side. The porous semiconductor layer 5 on the side of the second conductive layer 7 having a large thickness produces a light confinement effect due to light scattering and light reflection, so that the conversion efficiency can be increased.

  More specifically, as oxide semiconductor fine particles having a small average particle diameter, 100 wt% (wt%) having an average particle diameter of about 20 nm is used, and as the oxide semiconductor fine particles having a large average particle diameter, the average particle diameter is What is necessary is just to use 70 wt% of about 20 nm and 30 wt% of those having an average particle diameter of about 180 nm. By changing these weight ratios, average particle diameters, and respective film thicknesses, an optimum light confinement effect can be obtained. Further, by increasing the number of stacked layers from two layers to a plurality of layers, or by applying and forming so that these boundaries do not occur, the average particle diameter can be gradually increased from the substrate 2 side in the thickness direction. it can.

<Second conductive layer>
A second conductive layer 7 is formed on the counter electrode side substrate 9. The counter electrode side substrate 9 may be non-translucent or translucent. The counter electrode side substrate 9 is preferably an insulator, and in this case, a material excellent in durability against corrosion by the electrolyte 6 and bonding property with the glass sealing layer 10 can be freely selected. Reliability may be increased.

  Specifically, as the material of the counter electrode side substrate 9, glass such as white plate glass, soda glass, borosilicate glass, inorganic materials such as ceramics, polyethylene terephthalate (PET), polycarbonate (PC), acrylic, polyethylene naphthalate ( PEN), a resin material such as polyimide, and an organic-inorganic hybrid material are preferable. In order to secure electrical connection between the front and back surfaces of the counter electrode side substrate 9, a conductive layer made of titanium, stainless steel, aluminum, silver, copper, nickel, or the like may be coated around the counter electrode side substrate 9.

  Further, as the translucent counter electrode side substrate 9, at least in the wavelength range of visible light, for example, in the case of a white glass substrate having a thickness of 0.7 mm, light of 92% or more in a wavelength range of 400 to 1100 nm. In the case of a substrate of polyethylene terephthalate (PET) or polycarbonate (PC), the transmittance is about 90% for visible light, and the preferred light transmittance is 90% at least in the wavelength range of visible light. Any substrate having the above light transmittance can be used.

  Since the counter electrode side substrate 9 is installed for the purpose of holding a sufficient amount of the electrolyte 6 in the photoelectric conversion module 1, the thickness thereof is 0.5 to 50 mm, preferably 1 to 20 mm in terms of mechanical strength and cost. . If the thickness of the counter electrode side substrate 9 is less than 0.5 mm, the mechanical strength cannot be secured, and if it exceeds 50 mm, the cost increases. Moreover, when the counter electrode side board | substrate 9 forms the conductive layer around the insulator, the thickness of the conductive layer is 0.001-10 micrometers, Preferably 0.05-2.0 micrometers is good.

  The second conductive layer 7 is preferably an extremely thin film of platinum, carbon or the like having a catalytic function of facilitating transfer of charges with the electrolyte 6. In addition, an electrodeposited ultrathin film such as gold (Au), palladium (Pd), and aluminum (Al) can be used. In addition, a porous film made of fine particles of these materials, for example, a porous film of carbon fine particles can increase the surface area of the second conductive layer 7 and can contain the electrolyte 6 solution in the pores. Efficiency can be increased. Since the catalyst layer can be thin, it can also be made translucent.

  The second conductive layer 7 may be formed by forming a conductive film that complements the conductivity of the catalyst layer between the catalyst layer made of Pt or the like and the counter electrode side substrate 9. As the conductive film, either a non-light-transmitting layer or a light-transmitting layer can be used depending on the application. As a material for the non-light-transmitting conductive film, titanium, stainless steel, aluminum, silver, copper, gold, nickel, molybdenum, or the like is preferable. Further, a resin or conductive resin impregnated with fine particles or fine wires of carbon or metal may be used. As a material for the light-reflective and non-light-transmitting conductive film, a thin metallic thin film such as aluminum, silver, copper, nickel, titanium, stainless steel or the like, or for preventing corrosion by the electrolyte 6 Further, a film made of a metal oxide doped with impurities is preferably coated on a glossy metal thin film. In addition, as another conductive film, a Ti layer, an Al layer, and a Ti layer are sequentially laminated, and it is preferable that the conductive film is formed of a multilayer laminated body having improved adhesion, corrosion resistance, and light reflectivity. These conductive films can be formed by vacuum deposition, ion plating, sputtering, electrolytic deposition, or the like.

As the translucent conductive film, a tin-doped indium oxide film (ITO film), an impurity-doped indium oxide film (In ₂ O ₃ film), an impurity formed by a sputtering method of a low-temperature film growth method or a low-temperature spray pyrolysis method A doped tin oxide film (SnO ₂ film), an impurity-doped zinc oxide film (ZnO film), or the like is preferable. Further, a fluorine-doped tin dioxide film (SnO ₂ : F film) or the like formed by a thermal CVD method may be inexpensive. Moreover, the laminated body which improved the adhesiveness which laminated | stacked Ti layer, ITO layer, Ti layer one by one may be sufficient. In addition, an impurity-doped zinc oxide film (ZnO film) formed by a simple solution growth method may be used.

  As other film forming methods of these films, there are a vacuum deposition method, an ion plating method, a dip coating method, a sol-gel method and the like. By forming surface irregularities in the wavelength order of incident light on the conductive film by these film forming methods, a light confinement effect can be imparted. Further, a thin metal film such as light-transmitting Au, Pd, or Al formed by vacuum vapor deposition or sputtering may be used. The thickness of the light-transmitting conductive film is preferably 0.001 to 10 μm, more preferably 0.05 to 2.0 μm in terms of high conductivity and high light transmittance. When the thickness is less than 0.001 μm, the resistance of the conductive film increases. When the thickness exceeds 10 μm, the light transmittance of the conductive film decreases.

  Here, in the case where the second conductive layer 7 and the counter electrode side substrate 9 have translucency, light can be incident from either side of the main surface of the photoelectric conversion module 1, so that light can be incident from both main surface sides. Can increase the conversion efficiency.

<Glass sealing layer>
In FIG. 1, the glass sealing layer 10 prevents the electrolyte 6 solution from leaking to the outside, reinforces the mechanical strength, protects the laminate, and directly deteriorates the photoelectric conversion function in contact with the external environment. Provide for the purpose of preventing.

As the material of the glass sealing layer 10, glass (including Bi ₂ O ₃ , ZnO, B ₂ O ₃ , SiO ₂ , MgO, etc.) or glass frit mixed with carbon is excellent in sealing performance and weather resistance. Especially good. Carbon may be mixed into the glass sealing layer 10 as carbon particles, and the content thereof is preferably 0.1 to 20% by weight. If it is less than 0.1% by weight, the absorption of the laser beam is reduced, and if it exceeds 20% by weight, the formed film exhibits conductivity. The average particle size of the carbon particles is preferably 0.01 to 20 μm. If it is less than 0.01 μm, the particle surface is oxidized at a high temperature, and if it exceeds 20 μm, the thixotropy becomes high and screen printing becomes difficult.

  Firing can be performed in a short time by using laser light. In addition to this, heating and firing can be performed by focusing infrared light with a lens.

  The thickness of the glass sealing layer 10 is 0.1 μm to 6 mm, preferably 1 μm to 4 mm. In addition, it is sealed with heat-shielding, heat resistance, low contamination, antibacterial, antifungal, design, rust and abrasion resistance, antistatic, far infrared radiation, acid resistance, corrosion resistance, environmental friendliness, etc. By imparting to the stop layer 10, reliability and merchantability can be further enhanced.

<Conductor>
In FIG. 1, the conductor 8 is formed to electrically connect the second conductive layer 7 and the first conductive layer 3.

  The conductor 8 includes a glass frit (low melting point glass) covered with a glass layer 12, and preferably, the conductor 8 has at least one conductivity of aluminum, chromium, nickel, cobalt, and titanium. Contains particles. These conductive particles have an effect of reducing corrosion of the conductor 8 by the electrolyte 6 containing iodine.

  For example, the conductor 8 is one in which about 70 to 95% by weight of conductive particles such as aluminum and nickel are contained in a layer made of low-melting glass. In this case, when the content of the conductive particles is less than 70% by weight, an organic residue is likely to be generated, and when it exceeds 95% by weight, it becomes difficult to form a printed pattern. The average particle size of the conductive particles is preferably 0.5 to 15 μm. If the average particle size is less than 0.5 μm, the contribution to the conductivity is small, and if it exceeds 15 μm, it is difficult to obtain desirable pattern accuracy.

  The thickness of the conductor 8 is preferably 20 to 140 μm. If the thickness is less than 20 μm, the scattering intensity of the porous semiconductor layer 5 is likely to decrease. If the thickness exceeds 140 μm, current loss tends to increase in the electrolyte 6.

  The glass frit contained in the conductor 8 includes lead borosilicate glass, titanium oxide, or the like.

The glass layer 12 covering the conductor 8 is made of glass containing Bi ₂ O ₃ , ZnO, B ₂ O ₃ , SiO ₂ , MgO, or the like, and may be made of the same glass component as the glass sealing layer 10. In that case, the glass layer 12 may extend so that the glass sealing layer 10 covers the conductor 8, and can be baked by laser light irradiation in the same manner as the glass sealing layer 10.

  The thickness of the glass layer 12 covering the conductor 8 is preferably 100 to 300 μm. If the thickness is less than 100 μm, the conductor 8 is likely to be exposed to the electrolyte 6 due to a defect in pattern accuracy, and if it exceeds 300 μm, the light receiving area is reduced.

  Other conductors 8 include those made of a metal having corrosion resistance to the electrolyte 6 such as titanium, stainless steel, aluminum, silver, copper, gold, nickel, molybdenum, those made of an organic conductor such as carbon, or It is preferable that the surface of an insulator such as plastic or silicon dioxide is coated with a titanium layer, a stainless steel layer, a metal oxide layer, or the like having corrosion resistance to the electrolyte 6.

<Sensitizing dye>
Examples of the sensitizing dye 4 include ruthenium-tris, ruthenium-bis, osmium-tris, osmium-bis transition metal complexes, polynuclear complexes, ruthenium-cis-diaqua-bipyridyl complexes, phthalocyanines, porphyrins, polycycles, and the like. Xanthene dyes such as aromatic compounds and rhodamine B are preferred.

  In order to adsorb the sensitizing dye 4 to the porous semiconductor layer 5, the sensitizing dye 4 is substituted with at least one carboxyl group, sulfonyl group, hydroxamic acid group, alkoxy group, aryl group, phosphoryl group, etc. It is effective to have as. Here, the substituent is capable of firmly chemisorbing the sensitizing dye 4 itself to the porous semiconductor layer 5 and easily transferring charge from the excited sensitizing dye 4 to the porous semiconductor layer 5. I just need it.

  Examples of the method for adsorbing the sensitizing dye 4 to the porous semiconductor layer 5 include a method of immersing the porous semiconductor layer 5 formed on the substrate 2 in a solution in which the sensitizing dye 4 is dissolved.

Solvents for dissolving the sensitizing dye 4 when adsorbing the sensitizing dye 4 to the porous semiconductor layer 5 include alcohols such as ethanol, ketones such as acetone, ethers such as diethyl ether, acetonitrile, and the like. Or a mixture of two or more of these nitrogen compounds. The concentration of the sensitizing dye 4 in the solution is preferably about 5 × 10 ⁻⁵ to 2 × 10 ⁻³ mol / l (l (liter): 1000 cm ³ ).

  When adsorbing the sensitizing dye 4 to the porous semiconductor layer 5, the conditions of the temperature of the solution and the atmosphere are not particularly limited, and examples thereof include conditions of room temperature or heating of the substrate 2 under atmospheric pressure or in vacuum. . The time required for adsorption of the sensitizing dye 4 can be appropriately adjusted depending on the kind of the sensitizing dye 4 and the solution, the concentration of the solution, the circulation amount of the solution of the sensitizing dye 4 and the like. Thereby, the sensitizing dye 4 can be adsorbed to the porous semiconductor layer 5.

<Electrolyte>
As the electrolyte 6, a quaternary ammonium salt, a Li salt, or the like is used. As the composition of the electrolyte 6 solution, for example, a solution prepared by mixing tetrapropylammonium iodide, lithium iodide, iodine or the like with ethylene carbonate, acetonitrile, methoxypropionitrile, or the like can be used.

  In the present invention, the electrolyte 6 may be in a liquid form, but may be composed of a chemical gel that undergoes a phase change from a liquid phase body to a gel body. The phase change from the liquid phase body of the chemical gel to the gel body can be performed by heating.

  Further, the photoelectric conversion module 1 of the present invention has a thickness of a photoelectric conversion element composed of the first conductive layer 3, the porous semiconductor layer 5 adsorbing the sensitizing dye 4, the electrolyte 6, and the second conductive layer 7. The configuration is not limited to one provided in the direction, and a configuration in which a plurality of elements are stacked in the thickness direction may be employed.

  Moreover, the use of the photoelectric conversion module 1 of the present invention is not limited to the solar battery, but can be applied as long as it has a photoelectric conversion function, and can be applied to various light receiving elements, optical sensors, and the like.

  Examples of the photoelectric conversion module of the present invention will be described below.

  First, as a substrate 2, a glass substrate in which a first conductive layer 3 having a thickness of 1 μm made of fluorine-doped tin oxide having a sheet resistance of 5Ω / □ (square) as a first conductive layer 3 is formed on one main surface. (Length 5 cm × width 5 cm × thickness 2 mm) was used.

  Next, by applying a resist on the first conductive layer 3 and etching, patterning was performed so that four regions of the strip-shaped first conductive layer 3 were arranged. Of the four strip-shaped regions, one end also serving as an external electrode has a size of 4 cm in length × 1.5 cm in width, and the other three have a size of 4 cm in length × 1 cm in width. The interval between the regions was 0.5 mm. Thereby, four photoelectric conversion elements connected in series were arranged in a plane.

Next, a porous semiconductor layer 5 made of titanium dioxide was formed on each region of the first conductive layer 3. This porous semiconductor layer 5 was formed as follows. First, acetylacetone was added to a TiO ₂ anatase powder (average particle size 20 nm), and then kneaded with deionized water to prepare a titanium oxide paste stabilized with a surfactant. The prepared paste was applied onto each region of the first conductive layer 3 at a constant speed by a doctor blade method, and baked at 450 ° C. for 30 minutes in the atmosphere.

  Next, a glass substrate (length 5 cm × width 5 cm × thickness 2 mm) is used as the counter electrode-side substrate 9, and a sputtering apparatus and a Pt target are used on one main surface thereof as the second conductive layer 7 as a counter electrode layer. The platinum layer was formed with a thickness of about 200 nm so that the sheet resistance was 0.6 Ω / □. At this time, by forming the second conductive layer 7 using a metal mask, four strip-shaped regions were formed in the same manner as the first conductive layer 3.

  Next, as a paste for forming the conductor layer 8, a conductive paste containing molybdenum particles as a main component and mixed with glass frit (components: borosilicate glass, titanium oxide, etc.), an epoxy resin binder, and a butyl acetate solvent is used. In order to connect the first conductive layer 3 and the second conductive layer 7, the thickness that becomes the conductor layer 8 in each gap between the regions of the second conductive layer 7 on one main surface of the counter electrode side substrate 9. A 50 μm conductive paste layer was formed.

  In the conductive paste, the molybdenum particle content was 90% by weight, the glass frit content was 3% by weight, the epoxy resin binder content was 3% by weight, and the butyl acetate solvent content was 4% by weight. It was. The average particle diameter of the molybdenum particles was 6 μm.

Next, a glass paste that contains Bi ₂ O ₃ , ZnO, B ₂ O ₃ , SiO ₂ and MgO as glass components and further becomes a glass sealing layer 10 made of carbon particles, an epoxy resin binder, and a butyl acetate solvent is dispensed. The coating was applied to the peripheral edge of the counter electrode side substrate 9 while covering the exposed surface of the conductor layer 8. In the glass paste, the glass component content was 86% by weight, the carbon particle content was 7% by weight, the epoxy resin binder content was 3% by weight, and the butyl acetate solvent content was 4% by weight. The average particle size of the carbon particles was 4 μm.

  At this time, in order to form the through-hole 11 in a part of the glass sealing layer 10, the opening is about 50 μm × 500 μm by the dispenser method at two places of the applied glass paste layer for each photoelectric conversion element. A square through hole was formed.

  Arrange the substrate 2 and the counter electrode side substrate 9 so that the porous semiconductor layer 5 and the second conductive layer 7 face each other, and irradiate the conductive paste layer and the glass paste layer with a carbon dioxide laser beam, The conductive layer 8 was fired and sealed with the glass sealing layer 10.

  Next, the sensitizing dye 4 solution is injected into the photoelectric conversion module 1 through the through hole 11 using a tubing pump, and the sensitizing dye 4 solution is circulated in the photoelectric conversion module 1 for 5 hours at a flow rate of 5 ml per minute at room temperature. The sensitizing dye was adsorbed on the porous semiconductor layer 5. The sensitizing dye 4 solution (the content of the sensitizing dye 4 is 0.3 mmol / l) is obtained by using a sensitizing dye ("N719" manufactured by Solaronics SA) as a solvent and acetonitrile and t-butanol (volume ratio 1: What was dissolved in 1) was used.

Next, the solution of the electrolyte 6 was permeated into the porous semiconductor layer 5 through the through hole 11. In this example, iodine (I ₂ ), lithium iodide (LiI), and an acetonitrile solution, which are liquid electrolytes, were prepared and used as the electrolyte 6.

  Next, the sheet | seat which consists of olefin resin was covered so that the through-hole 11 might be plugged from the outside, and it heated and formed the through-hole sealing part.

When the photoelectric conversion characteristics of the photoelectric conversion module 1 obtained in this way were evaluated, the conversion efficiency was 5.2% at AM 1.5 and 100 mW / cm ² . When this photoelectric conversion module 1 was subjected to a high temperature standing test in the dark at 85 ° C., the photoelectric conversion efficiency exceeding 70% before the test was maintained even after 100 hours had elapsed.

  As described above, it was confirmed that the photoelectric conversion module 1 of the present example has high conversion efficiency and exhibits higher durability.

It is sectional drawing which shows an example of embodiment about the photoelectric conversion module of this invention. It is a top view which shows an example of embodiment about the photoelectric conversion module of this invention.

Explanation of symbols

1: Photoelectric conversion module 2: Substrate 3: First conductive layer 4: Sensitizing dye 5: Porous semiconductor layer
6: Electrolyte 7: Second conductive layer 8: Conductor 9: Counter electrode substrate 10: Glass sealing layer 11: Through hole 12: Glass layer

Claims (2)

A first conductive layer as one electrode on which a porous semiconductor layer carrying a sensitizing dye is formed, and a second conductive layer as a counter electrode arranged opposite to the porous semiconductor layer A method of manufacturing a photoelectric conversion module, wherein an electrolyte is disposed to form a photoelectric conversion element, and a plurality of the photoelectric conversion elements are arranged to manufacture a photoelectric conversion module, wherein the first of the photoelectric conversion elements Applying a conductive paste containing glass frit for electrically connecting the conductive layer and the second conductive layer of the photoelectric conversion element adjacent to the conductive layer to at least one of the first and second conductive layers; Next, a glass paste is applied around the conductive paste, and then the conductive paste and the glass paste are irradiated with laser light and fired to form a conductor and a glass layer. light Method of manufacturing a conversion module. After forming the photoelectric conversion element, a glass paste is applied around the photoelectric conversion element, and then a glass sealing layer is formed by irradiating the glass paste with laser light and baking. The manufacturing method of the photoelectric conversion module of Claim 1.

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