JP5398256B2 - Photoelectric conversion device - Google Patents

Description

  The present invention relates to a photoelectric conversion device, and more particularly to a photoelectric conversion device suitably used as a dye-sensitized solar cell.

  There are various types of solar cells, such as a bulk crystal silicon solar cell or a thin film amorphous silicon solar cell using an amorphous silicon thin film. Further, for the purpose of reducing silicon raw materials, a dye-sensitized solar cell has attracted attention as a next-generation solar cell that does not use silicon.

As such a dye-sensitized solar cell, a first electrode made of a semiconductor carrying a sensitizing dye, a second electrode disposed so as to face the first electrode, and a pair of these And an electrolyte injected between the electrodes. This electrolyte is stored in a highly confidential electrolyte chamber so as not to leak outside. Such an electrolyte chamber is formed by interposing a frame-shaped glass frit between the first electrode and the second electrode and melting the glass frit by laser heating (see, for example, Patent Document 1). ).
JP 2004-172048 A

  However, the dye-sensitized solar cell disclosed in Patent Document 1 requires a semiconductor layer thickness of 10 μm or more. In order to form an electrolyte chamber that can accommodate a semiconductor layer having such a thickness, the thickness of the glass frit needs to be 10 μm or more. Thus, when the thickness of the glass frit increases, the volume of the glass frit melted by laser heating increases, and the thermal strain of the glass frit increases. As a result, the glass frit may peel off or the substrate may break, making it difficult to maintain the airtightness for a long time.

  The present invention has been completed in view of the above-described conventional problems, and an object of the present invention is to obtain a highly reliable photoelectric conversion device that can maintain hermeticity for a long period of time.

One embodiment of the present invention includes a light-transmitting substrate having a first main surface, a support substrate having a second main surface facing the first main surface, the first main surface, and the second main surface. And a side wall portion surrounding the photoelectric converter and joining the translucent substrate and the support substrate. The side wall includes a frame provided on at least one of the translucent substrate or the support substrate, and a bonding portion laminated on the frame and having a larger absorption coefficient than the frame. Yes. A translucent substrate having a first main surface, a support substrate having a second main surface opposite to the first main surface, and between the first main surface and the second main surface A dye-sensitized photoelectric converter provided; and a side wall that surrounds the photoelectric converter and joins the translucent substrate and the support substrate. Further, the side wall portion includes a frame portion provided on at least one of the translucent substrate or the support substrate, and a joint portion laminated on the frame portion and having a larger absorption coefficient for laser light than the frame portion. It has. Furthermore, the softening point of the frame portion is lower than the softening point of the translucent substrate provided with the frame portion or the support substrate provided with the frame portion, and the laser beam is irradiated to the joint portion. Thus, the translucent substrate and the support substrate are bonded via the side wall portion.

  Thus, since the side wall portion includes the frame portion and the bonding portion having a larger absorption coefficient than the frame portion, for example, when the translucent substrate and the support substrate are bonded by heating with a laser. In addition, the joint portion in the side wall portion can be selectively melted. Thereby, the volume of the melted portion can be reduced, and thermal strain can be suppressed. As a result, the occurrence of peeling and breakage can be suppressed, and the airtightness can be maintained for a long time.

  In another aspect, the frame portion is provided on each of the translucent substrate and the support substrate.

  In another aspect, the softening point of the joint portion is lower than the softening point of the frame portion.

  In another aspect, the joint includes a light absorber.

In another aspect, the distance between the inner surface on the photoelectric conversion body side in the joint and the outer surface on the opposite side of the photoelectric conversion body is the opposite side of the inner surface on the photoelectric conversion body side and the photoelectric conversion body in the frame portion . It is smaller than the distance to the outer surface .

  In another aspect, the frame portion is provided on the translucent substrate, an electrode is formed on the first main surface, and the electrode is disposed at an interface between the frame portion and the translucent substrate. It is extended.

  In another aspect, the frame portion is provided on the support substrate, an electrode is formed on the second main surface, and the electrode extends to an interface between the frame portion and the translucent substrate. ing.

  According to the photoelectric conversion device of the present invention, when the translucent substrate and the support substrate are bonded via the side wall portion, it is possible to suppress the occurrence of peeling or breakage, and to maintain the airtightness for a long period of time.

  Embodiments according to the photoelectric conversion device of the present invention will be described below in detail with reference to the drawings schematically shown.

  FIG. 1 is a cross-sectional view showing a first embodiment of the photoelectric conversion device of the present invention. The photoelectric conversion device X includes a pair of substrates (hereinafter, referred to as a first substrate 1 and a second substrate 8) that are disposed so that their principal surfaces face each other. A first electrode 2 and a second electrode 7 are formed on one main surface of the first substrate 1 and the second substrate 8, respectively.

  In the photoelectric conversion device X, the electrolyte 3 is disposed in a gap between one main surface of the first substrate 1 and the second substrate 8. In other words, the electrolyte 3 is disposed so as to be sandwiched between the first electrode 2 and the second electrode 7. The electrolyte 3 is covered with a frame portion 6 and a joint portion 5 having a larger absorption coefficient than the frame portion 6 in order to prevent leakage to the outside. The frame portion 6 and the joint portion 5 constitute a side wall portion, and the side wall portion joins the first substrate 1 and the second substrate 8. On the first electrode 2, a semiconductor layer 4 carrying a pigment is formed. The semiconductor layer 4 and the electrolyte 3 constitute a photoelectric conversion body.

  The second substrate 8 and the second electrode 7 are formed with injection holes 9 for injecting the electrolyte 3 from the outside. In the photoelectric conversion device X, a sealing member 10 that closes the injection hole 9 is provided on the other main surface side of the second substrate 8 in order to prevent the electrolyte 5 from leaking to the outside. The sealing member 10 is further covered with a protective member 11. Here, when the electrolyte 3 is a gel or quasi-solid having low fluidity, injection from the injection hole 9 is difficult, so the semiconductor layer 4 is sealed before the first substrate 1 and the second substrate 8 are sealed. After the electrolyte 3 is formed thereon, the second substrate 8 may be used to form a seal with the first substrate 1 and a bond with the electrolyte 3.

  And in the photoelectric conversion apparatus X which concerns on the 1st Embodiment of this invention, in order to fully absorb sunlight, it is preferable that the thickness of the semiconductor layer 4 shall be 10 micrometers or more. In this case, the electrode interval between the first electrode 2 and the second electrode 7 is required to be 10 μm or more, but with this configuration, the airtightness can be maintained for a long time. That is, when the first substrate 1 and the second substrate 8 are bonded by heating with a laser, the bonding portion 5 in the side wall portion can be selectively melted. Thereby, the volume of the melted portion can be reduced, and thermal strain can be suppressed. As a result, it is possible to suppress peeling and breakage. In addition, since the thin joint 5 can be locally heated by a laser while securing the distance between the first and second substrates at the frame 6, it is possible to suppress the first and second substrates from being distorted and joined. You can also

  The photoelectric conversion apparatus X is produced as follows, for example. First, a paste made of glass frit is printed on the second electrode 7, and this is thermally baked to form the frame portion 6. Thereafter, a paste made of glass frit having a larger absorption coefficient than that of the frame portion 6 is printed on the frame portion 6 and is thermally baked to form the joint portion 5. Then, the first electrode 2 is brought into contact with the bonding portion 5 so that the first electrode 2 faces the second electrode 7.

  Or the frame part 6 is formed by printing the paste which consists of glass frit on the 2nd electrode 7, and heat-firing. On the other hand, a paste made of glass frit having a softening point lower than that of the frame portion 6 is printed on the first electrode 2 and is thermally baked to form the joint portion 5. And you may make the frame part 6 and the junction part 5 contact.

  Thereafter, the joining portion 5 is heated and melted by irradiating the joining portion 5 with laser light that can pass through the first substrate 1 and the first electrode 2. Thereafter, by cooling the bonding portion 5, the first electrode 2 and the second electrode 7 are sealed, in other words, the first substrate 1 and the second substrate 8 are sealed.

  For example, when 50 μm is required as the electrode interval between the first electrode 2 and the second electrode 7, the side wall is formed of a frame portion 6 having a thickness of 40 μm and a joint portion 5 having a thickness of 10 μm. And when this side wall part is heated with a laser, the junction part 5 can be selectively melted and sealed. Therefore, compared with the case where the junction part 5 with a film thickness of 50 μm is used, the amount of heat at the time of laser heating can be reduced, and thermal strain, thermal stress and the like can be suppressed. As a result, cracking and peeling of the first substrate, the second substrate, or the side wall can be suppressed, the electrolyte solution 3 can be sealed well, and the penetration of moisture and oxygen from the outside to the electrolyte solution 3 can be suppressed. it can.

  Below, the detail of the member which comprises the photoelectric conversion apparatus which concerns on the 1st Embodiment of this invention mentioned above is shown.

<First and second substrates>
The 1st board | substrate 1 consists of a translucent board | substrate which is mainly provided in the light incident side and can permeate | transmit the light absorbed with a photoelectric conversion body. Here, translucency refers to light having a transmittance of 10% or more at any wavelength among light absorbed by the photoelectric conversion body including the semiconductor layer 4 and the electrolyte 3. From the viewpoint of increasing the photoelectric conversion efficiency, the transmittance is preferably 80% or more. The first substrate 1 has a first main surface. The first substrate 1 supports the first electrode 2 formed on the first main surface.

  As the material of the first substrate 1, for example, a material having translucency with respect to visible light is used. Preferably, glass materials such as blue plate glass, white plate glass and non-alkali glass, or resin materials such as PET (polyethylene terephthalate) and PEN (polyethylene naphthalate) are used. Further, tempered glass may be used as a countermeasure for falling.

  The second substrate 8 has a second main surface and is a support substrate that supports the second electrode 7 on the second main surface. If the second substrate 8 is made of a light-transmitting material similar to the first substrate 1, the light incident surface (light receiving surface) can be further enlarged and the photoelectric conversion efficiency can be increased. . Further, since the second substrate 8 does not have to be positioned on the light incident side, the second substrate 8 may have a small translucency. The material of the second substrate 8 may be any material as long as it can function as a support substrate, but the second substrate 8 itself acts as an electrode as long as it is a conductive metal material. Therefore, the second electrode 7 is not necessary, and the number of parts can be reduced. Examples of such a metal material having conductivity include metal materials such as titanium, tantalum, niobium, nickel, tungsten, stainless steel, and aluminum alloy. The second substrate 8 is preferably made of titanium, nickel or tungsten from the viewpoint of improving the corrosion resistance with respect to the electrolyte 3. In this case, if a later-described catalyst layer (not shown) is provided on the second substrate 8, charge transfer to the electrolyte 3 can be efficiently performed.

  The second substrate 8 is formed with an injection hole 9 for injecting the electrolyte 3 from the outside. The shape and the like of the injection hole 9 are not particularly limited as long as the electrolyte 3 can be injected between the first and second substrates. The injection hole 9 may have, for example, a circular shape, an elliptical shape, a polygonal shape such as a quadrangular shape, or the like. As the size of the injection hole 9, for example, if the cross-sectional shape is circular, the diameter is preferably about 0.1 to 3 mm. In the present embodiment, only one injection hole 9 is provided, but a plurality of injection holes 9 may be provided. Further, in the present embodiment, the injection hole 9 is provided in the second substrate 8, but it may be provided only in the first substrate 1, or may be provided in each of the first and second substrates. Good. The injection hole 9 can be used not only for injecting the electrolyte 3, but also for discharging the electrolyte 3, injecting the dye solution, or discharging the dye solution.

<First and second electrodes>
The first electrode 2 has a function of extracting the current generated by the semiconductor layer 4 to the outer surface side of the photoelectric conversion device, and is provided on the first main surface of the first substrate 1. The first electrode 2 is visible since light is incident from the side of the main surface opposite to the first main surface of the first substrate 1 (hereinafter referred to as the other main surface of the first substrate 1). It is preferable to have translucency with respect to light.

  The material of the first electrode 2 is, for example, an ITO (tin-doped indium oxide: indium tin oxide) layer, an FTO (fluorine-doped tin oxide) layer, or a tin oxide layer. In addition, the thickness of the first electrode 2 is preferably about 0.3 to 2 μm from the viewpoint of easy manufacturing and appropriate sheet resistance. Such a first electrode 3 is formed in a layer form by, for example, a CVD method, a sputtering method, or a spray method.

  The second electrode 7 is for transferring electric charge to the electrolyte 3 and is provided on the second main surface of the second substrate 8. As a material of the second electrode 7, if the second substrate 8 is also used as a light receiving portion, the same material as the first electrode 2, that is, the above-described light-transmitting material may be used. On the other hand, as long as light is not received from the second substrate 8, the second electrode 7 does not have to be made of a translucent material. For example, the second electrode 7 is made of a metal material such as titanium, nickel, or tungsten. Also good.

  The second electrode 7 is made of Pt, Pd, Ru, Os, Rh, Ir, or the like, carbon, PEDOT: TsO (polyethylenedioxythiophene-toluenesulfonate), or the like on the contact surface with the electrolyte 3. If a catalyst layer (not shown) is formed, charge transfer to the electrolyte 3 can be performed efficiently.

<Electrolyte>
The electrolyte 3 has a function of passing the charge received from the second electrode 7 to the dye supported on the semiconductor layer 4. The electrolyte 3 only needs to be in a state where it can be injected from the injection hole 9. For example, a liquid (electrolytic solution) or a gel can be used, and the electrolyte 3 may be solid after injection. Alternatively, the electrolyte 3 may be directly applied on the first substrate 1 or the second substrate 8 and then vacuum-sealed with a facing substrate.

  Examples of the electrolyte 3 include iodine / iodide salts, bromine / bromide salts, cobalt complexes, and potassium ferrocyanide. The notation “iodine / iodide salt” means that the content of iodine and iodide salt changes due to the chemical reaction of the electrolyte.

  When the electrolyte 3 is liquid, a solvent can be used as a matrix. As the solvent, a molecular liquid, an ionic liquid, or a room temperature molten salt is used. As the molecular liquid, acetonitrile, methoxypropionitrile, γ-butyrolactone, propylene carbonate, dimethyl sulfoxide, or the like is used. As the ionic liquid, hexylmethylimidazolium iodide (HMImI), 1-ethyl-3-methylimidazolium-bis (trifluoromethanesulfonyl) imide (EMI-TFSI) or the like is used.

  In addition, when the electrolyte 3 is liquid or gel at the time of injection and becomes solid after injection, a solid electrolyte, a conductive polymer, an organic molecular electron transport agent, or the like is used. As the solid electrolyte, a gel electrolyte or a polymer electrolyte is used. For example, a poly (vinylidene fluoride-hexafluoropropylene) copolymer (PVdF-HFP) or the like may be used as a gelling agent for the gel electrolyte. As the conductive polymer, polythiophene, polypyrrole, polyphenylene vinylene, or the like is used. As the organic molecular electron transfer agent, a fullerene derivative, a pentacene derivative, a perylene derivative, a triphenyldiamine derivative, or the like is used. The thickness of the electrolyte 3, that is, the distance between the first main surface of the first substrate 1 and the second main surface of the second substrate 8 is preferably about 1 to 500 μm.

<Sidewall>
The side wall portion joins the first substrate 1 (translucent substrate) and the second substrate 8 (support substrate), and photoelectric conversion is performed by the first substrate 1, the second substrate 8, and the side wall portion. A storage space for storing the body is formed. In addition, the side wall portion includes a frame portion 6 provided on at least one of the first substrate 1 or the second substrate 8 and a bonding portion 5 stacked on the frame portion 6. Further, the bonding portion 5 has an absorption coefficient larger than that of the frame portion 6.

In the present invention, “the bonding portion 5 has a larger absorption coefficient than the frame portion 6” means that the absorption coefficient of the bonding portion 5 at a specific wavelength is larger than that of the frame portion 6. Means. By using a laser beam having an emission wavelength at this specific wavelength, the junction 5 can be selectively heated. From the viewpoint of heating the junction 5 more selectively and efficiently with a laser, the absorption coefficient of the junction 5 in the wavelength range of 180 nm to 10.6 μm including the wavelength of an excimer laser, a CO ₂ laser, or the like is a frame. It is better that it is larger than the part 6. More preferably, from the viewpoint of suppressing damage to members such as the frame portion 6, it is preferably 350 nm to 1500 nm including the wavelength of the blue laser or YAG laser. The absorption coefficient can be determined from the absorbance, concentration, and passage distance after measuring the absorbance with an ultraviolet-visible spectrophotometer or the like. In addition, if conditions, such as the thickness of a measuring object, are made the same, it is also possible to evaluate by an absorbance or an absorptivity instead of an absorption coefficient.

  Here, the frame portion 6 is provided on at least one of the first substrate 1 or the second substrate 8 when the frame portion 6 is directly provided on the first substrate 1. Is provided directly on the second substrate 8, the frame portion 6 is provided on the first substrate 1 via the first electrode 2, or the frame portion 6 is interposed on the second electrode 7. Including the case of being provided on the second substrate 8.

  The frame portion 6 may be formed integrally with the first substrate 1 or the second substrate 8, or may be formed by joining another member to the first substrate 1 or the second substrate 8. Good. When the frame portion 6 is formed integrally with the first substrate 1 or the second substrate 8, for example, the center portion of the main surface of the substrate is formed into a concave shape by cutting or etching, so that the frame The part 6 can be formed. In this case, since there is no bonding interface between the frame portion 6 and the first or second substrate, the mechanical strength of the photoelectric conversion device can be increased. Moreover, when the frame part 6 is provided by joining another member to a board | substrate, the frame part 6 can be formed easily and a process can be simplified.

  The frame portion 6 may be provided on the first substrate 1, may be provided on the second substrate 8, or may be provided on both the first substrate 1 and the second substrate 8. Good.

The frame portion 6 is a material having high airtightness to the electrolyte 3 and high corrosion resistance, and a glass material or a resin material is used. Examples of the glass material include lead glass, bismuthate glass, borosilicate glass, phosphate glass, zinc borosilicate glass, SiO _x —BiO _y —MO _z glass (SiO ₂ , Bi ₂ O ₃ And other metal oxide composition glass), BO _x -BiO _y -MO _z- based glass (including B ₂ O ₃ , Bi ₂ O ₃ and other metal oxide composition glass), _{SiO x -CaO y -Na (K)} O z -MO w based glass _(SiO 2, CaO, including glass and composition of Na _{(K) 2} O and other metal oxides), or _PO x -MgO _y Based glass (including glass composed of P ₂ O ₅ , MgO and other metal oxides). Further, a crystalline oxide such as alumina or silicon carbide may be included in the frame portion 6 as thermal expansion adjustment or rheology adjustment with the first or second substrate.

  Examples of the resin material used for the frame 6 include polyethylene, modified polyethylene, maleic acid modified polyethylene, polypropylene, modified polypropylene, maleic acid modified polypropylene, ionomer resin, fluorine resin, butyl resin, epoxy resin, or acrylate resin. Can be mentioned. Moreover, these resin materials may contain a filler etc. as needed from a viewpoint of improving mechanical strength.

  The joint portion 5 is stacked on the frame portion 6. As shown in FIG. 1, the joint 5 is between the frame 6 and the first substrate 1, between the frames 6 as shown in FIG. 2, or between the second substrate 8 and the frame 6. It may be provided.

  The joint portion 5 is melted entirely or partially by light irradiation and has an adhesive action. What has an adhesive action by light irradiation is one that converts irradiated light into heat and softens by this heat, one that converts irradiated light into heat and cures by this heat, or irradiated Examples include those that are cured by light.

  The joint portion 5 has a larger absorption coefficient than the frame portion 6. Thereby, light can be selectively absorbed with respect to the joint portion 5 to promote the adhesive action. From the viewpoint of promoting such a selective adhesive action, the absorption coefficient of the joint portion 5 is preferably 10 times or more that of the frame portion 6.

  The joint portion 5 is a material having high airtightness and high corrosion resistance to the electrolyte 3 like the frame portion 6, and a metal material, a glass material, a resin material, or the like is used. About such a glass material and a resin material, the material used with the above-mentioned frame part 6 can be used.

  Moreover, the junction part 5 may include a light absorber so that light such as laser light can be efficiently absorbed. Examples of the light absorber include materials such as indium, zinc, gallium, silver, tin, aluminum, lead, bismuth, copper, and antimony when the junction 5 is a metal material. Used as a compound or mixture of more than one species. Moreover, when the junction part 5 is a glass material, materials, such as chromium, iron, nickel, cobalt, manganese, copper, or carbon, are mentioned, These are used as a single substance, an oxide, or these 2 or more types of compounds, a mixture. It is done. Moreover, when the junction part 5 is a resin material, materials, such as pigment | dyes and pigments, such as a phthalocyanine, porphyrin, cyanine, polymethine, carbon black, titanium oxide, or chromium oxide, are mentioned, These simple substance or these 2 or more types of materials Used as a mixture. When the junction 5 includes a light absorber, the laser beam can be efficiently absorbed, so that the junction 5 can be easily heated and melted. As a result, the amount of irradiation energy by the laser can be reduced, or the laser light source can be made small, and the power consumption can be reduced. Alternatively, the laser scanning speed can be increased, and the manufacturing cost can be reduced. Moreover, since the absorption coefficient of the junction 5 can be increased, the amount of energy irradiated by the laser can be reduced, and the amount of heat can be reduced, so that thermal distortion can be suppressed and sealing can be performed with a high yield. Moreover, since the absorption coefficient of the junction part 5 can be increased, even if the thickness of the junction part 5 is reduced, light can be absorbed only by the junction part 5, and the lower material is irradiated with light in the light irradiation direction. Therefore, it is difficult to heat, and thermal damage to the lower material can be suppressed.

  Both the frame portion 6 and the joint portion 5 are preferably made of a material that is softened by heat. With such a configuration, when the joining portion 5 is selectively softened by irradiating light such as laser light, the surface portion of the frame portion 6 can be softened to some extent by the heat. As a result, it is possible to suppress the occurrence of strain and damage at the interface between the joint portion 5 and the frame portion 6.

  In particular, it is preferable that the frame portion 6 and the joint portion 5 are mainly composed of a glass material. Thereby, both sealing performance and durability can be improved. The frame part 6 and the joint part 5 are formed by applying a glass frit paste by a printing method or using a dispenser and then thermally baking. In addition, about the junction part 5, it is preferable that it is a glass frit containing a laser absorption component and a glass component. This laser-absorbing component plays a role of efficiently melting and sintering the glass frit by selectively absorbing laser light and converting the energy into heat. The laser absorbing component is preferably melted as a part of the matrix forming the glass frit, but may be segregated in the matrix. Further, if the thermal expansion coefficient of the glass frit is close to the thermal expansion coefficient of the first substrate 1 or the second substrate 8 or 1 to 20% lower, the occurrence of defects such as cracks can be reduced. Can do.

  The softening point (or melting point) of the joint portion 5 is preferably lower than the softening point (or melting point) of the frame portion 6. Preferably, the difference in softening point (or melting point) between the frame portion 6 and the joint portion 5 is preferably 50 ° C. or more. Thereby, the softening by the heating of the junction part 5 can be promoted more selectively, and the thermal distortion of the frame part 6 can be reduced. More preferably, the difference between the softening points (or melting points) of the frame portion 6 and the joint portion 5 is in the range of 50 to 100 ° C. As a result, thermal strain is reduced for most of the frame portion 6, and the interface portion of the frame portion 6 with the joint portion 5 is softened to some extent to relieve stress at the interface with the joint portion 5. Can do. As a result, the thermal distortion of the side wall portion can be further reduced. For example, the softening point of the frame portion 6 is 400 ° C. to 600 ° C., and the softening point of the joint portion 5 is preferably 300 ° C. to 500 ° C. Note that the softening point of the frame portion 6 and the joint portion 5 can be adjusted by the material composition ratio.

  In the present invention, the softening point refers to a temperature at which deformation flow starts when the temperature is raised. The softening point can be measured by thermomechanical measurement. Examples of the thermomechanical measurement include a thermal expansion (TMA) method or an intrusion method. In the penetration method, the softening point is when the viscosity η (dPa · s) is log η = 7.6.

Softening point of the frame portion 6 (or melting point) is not lower than the softening point of the first or second substrate to which it is provided (or melting point). Preferably, the difference in softening point (or melting point) between the first or second substrate and the frame portion 6 provided thereon is preferably 200 ° C. or more. Thereby, when the frame part 6 is heated and joined to the first or second substrate, deformation or thermal strain of the first or second substrate can be reduced.

  Moreover, it is preferable that each softening point (or each melting | fusing point) of the 1st or 2nd board | substrate, the frame part 6 provided in it, and the junction part 5 is comprised so that it may reduce in order. Thereby, the deformation | transformation as the whole photoelectric conversion apparatus can be suppressed.

  Each material is preferably diffused or mixed at the interface between the frame portion 6 and the joint portion 5. Thereby, the intensity | strength of an interface increases and sealing property can be improved. Such a configuration can be formed by adjusting materials and heating conditions so that the interface portion between the frame portion 6 and the joint portion 5 is also softened simultaneously when the joint portion 5 is softened with a laser or the like.

The joint portion 5 preferably has a width smaller than that of the frame portion 6. Here, the width means the distance between the inner surface of the bonding portion 5 or the frame portion 6 on the semiconductor layer 4 side and the outer surface on the outside. With this configuration,
The heating region, the melting region, and the sealing region can be reduced, and the thermal distortion of the first substrate 1, the second substrate 8, and the side wall itself can be reduced. Positioning of the frame part 6 and the joint part 5 is also facilitated. As a result, it is possible to suppress peeling of the joint 5 and cracking of the substrate. Preferably, from the viewpoint of achieving both improvement in sealing performance and suppression of thermal strain, the width of the joint portion 5 is preferably 0.1 to 1.0 times the width of the frame portion 6.

  As a method of bonding the first substrate 1 and the second substrate 8 via the frame portion 6 and the bonding portion 5, in the case of the configuration of FIG. 1, for example, the following method is used. First, a glass frit paste is applied on the second substrate 8 and then thermally baked to form the frame portion 6. Next, a glass frit paste is applied onto the frame portion 6 or the first substrate 1 and then thermally baked to form the joint portion 5. Next, the first substrate 1 and the second substrate 8 are arranged to face each other so that the bonding portion 5 is sandwiched between the frame portion 6 and the first substrate 1. Then, for example, a laser beam such as a YAG laser or a semiconductor laser is irradiated to the joint portion 5 or the periphery of the joint portion 5 through the first substrate 1 to selectively melt the joint portion 5. The first substrate 1 and the second substrate 8 are bonded.

  In the case of the configuration of FIG. 2, for example, the following method is used. First, the first frame portion 6 is formed on the second substrate 8, and the bonding portion 5 is further formed on the frame portion 6. Further, the frame portion 6 is also formed on the first substrate 1. Next, this 1st board | substrate 1 and the 2nd board | substrate 8 are arrange | positioned so that the junction part 5 may be pinched | interposed between each frame part 6. FIG. Then, the laser beam is irradiated to the joint portion 5 through the first substrate 1 and the frame portion 6, and the joint portion 5 is heated and melted to seal the frame portion 6 and the joint portion 5. The substrate 1 and the second substrate 8 are sealed. The above description is a case where the laser beam is irradiated to the bonding portion 5 through the first substrate 1 and the frame portion 6. However, the laser beam is irradiated to the bonding portion 5 through the second substrate 8 and the frame portion 6. May be.

  As the laser used here, a gas laser, a YAG laser, a semiconductor laser, a dye laser, or the like is used. Irradiation with laser light (beam) may be performed while scanning the first or second substrate, or may be performed while scanning with laser light (beam).

  As shown in FIG. 1, when the frame portion 6 is provided on the second substrate 8, the second electrode 7 formed on the second main surface is connected to the frame portion 6 and the second substrate 8. It is preferable to extend to the interface. That is, the second electrode 7 is formed on the second main surface of the second substrate 8, and the frame portion 6 is formed on the second electrode 7. With such a configuration, since the second electrode 7 is protected by the frame portion 6, when the bonding portion 5 is heated to bond the first substrate 1 and the second substrate 8, the second electrode 7 is protected. It is possible to suppress the thermal stress from being transmitted to the electrode 7. As a result, the conduction reliability of the second electrode 7 can be improved.

  In particular, it is preferable that the second main surface of the second substrate 8 is a flat surface, and the frame portion 6 is formed after the second electrode 7 is formed on the flat surface. Thereby, since there is no bent surface when the second electrode 7 is formed in a layered manner by the CVD method, the sputtering method, the spray method, or the like, it is possible to suppress the disconnection or the increase in resistance of the second electrode 7.

  When the frame portion 6 is provided on the first substrate 1, the first electrode 2 formed on the first main surface extends to the interface between the frame portion 6 and the first substrate 1. It is preferable. That is, the first electrode 2 is formed on the first main surface of the first substrate 1, and the frame portion 6 is formed on the first electrode 2. With such a configuration, the first electrode 2 is protected by the frame portion 6. Therefore, when the bonding portion 5 is heated to bond the first substrate 1 and the second substrate 8, the first electrode 2 is protected. It is possible to suppress the thermal stress from being transmitted to the electrode 2. As a result, the conduction reliability of the first electrode 2 can be improved.

  In particular, it is preferable that the first main surface of the first substrate 1 is a flat surface, and the frame portion 6 is formed after the first electrode 2 is formed on the flat surface. Thereby, since there is no bending surface when the first electrode 2 is formed in a layer form by the CVD method, the sputtering method, the spray method, or the like, it is possible to suppress disconnection or high resistance of the first electrode 2.

  Further, when the frame portion 6 is an insulator, the first electrode 2 and the second electrode 7 can be sealed without conducting even if a metal is used for the joint portion 5.

<Semiconductor layer>
The semiconductor layer 4 is composed of a porous body having a function of supporting the pigment in the pores. Thus, since the porous semiconductor layer 4 has a large surface area and can carry (adsorb) more dye (not shown), it absorbs light efficiently and contributes to improvement in photoelectric conversion efficiency.

  Examples of the material of the porous semiconductor layer 4 include titanium (Ti), zinc (Zn), tin (Sn), niobium (Nb), indium (In), yttrium (Y), and lanthanum (La). At least one metal such as zirconium (Zr), tantalum (Ta), hafnium (Hf), strontium (Sr), barium (Ba), calcium (Ca), vanadium (V), or tungsten (W) An oxide semiconductor is preferable. Further, the semiconductor layer 4 contains one or more kinds of nonmetallic elements such as nitrogen (N), carbon (C), fluorine (F), sulfur (S), chlorine (Cl), or phosphorus (P). May be. In particular, titanium oxide is preferable because the electron energy band gap is in the range of 2 to 5 eV, which is larger than the energy of visible light. The porous semiconductor layer is preferably an n-type semiconductor whose conduction band is lower than that of the dye at the electron energy level.

  Further, since the semiconductor layer 4 is a porous body, it has a large number of fine pores (having a pore diameter of preferably about 10 to 40 nm) inside. Moreover, the thickness of the semiconductor layer 4 is 1-50 micrometers from a viewpoint of optimizing a photoelectric conversion effect | action, More preferably, 10-30 micrometers is good. In addition, an extremely thin (thickness: about 200 nm) dense layer of an n-type oxide semiconductor such as titanium oxide or niobium oxide may be inserted between the semiconductor layer 4 and the first electrode 2, and the effect of suppressing the reverse current. There is.

  The dye is preferably, for example, a transition metal complex, a polynuclear complex, a ruthenium-cis-diaqua-bipyridyl complex, a phthalocyanine, a porphyrin, a polycyclic aromatic compound, or a xanthene-based one. Examples of the transition metal complex include ruthenium-tris type, ruthenium-bis type, osmium-tris type, and osmium-bis type. An example of xanthene is rhodamine B.

  In order to adsorb the dye to the porous semiconductor layer 4, it is effective that the dye has at least one carboxyl group, sulfonyl group, hydroxamic acid group, alkoxy group, aryl group, phosphoryl group, or the like as a substituent. It is. Here, the substituent may be any as long as it can strongly adsorb the dye itself to the porous semiconductor layer 4 and can easily transfer charges from the excited sensitizing dye to the porous semiconductor layer 4.

Examples of the method for adsorbing the pigment on the semiconductor layer 4 include a method of immersing the semiconductor layer 4 formed on the first substrate 1 in a solution in which the pigment is dissolved. When the dye is adsorbed on the semiconductor layer 4, the solvent of the solution for dissolving the dye includes, for example, alcohols such as ethanol, ketones such as acetone, ethers such as diethyl ether, or nitrogen compounds such as acetonitrile. What mixed 1 type (s) or 2 or more types is mentioned. The concentration of the dye in the solution is preferably about 5 × 10 ⁻⁵ to 2 × 10 ⁻³ mol / l (l (liter): 1000 cm ³ ).

  Although the semiconductor layer 4 is formed on the first substrate 1 side which is a light-transmitting substrate in FIG. 1, the semiconductor layer 4 may be formed on the second substrate 8 side. In this case, light passes through the first substrate 1, the first electrode 2, and the electrolyte 3 and enters the semiconductor layer 4. In this arrangement, a catalyst layer (not shown) may be formed on the surface of the first electrode 2 of the first substrate 1. Thereby, the charge transfer to the electrolyte 3 can be performed efficiently.

<Sealing member and protective member>
The sealing member 10 and the protection member 11 are members for preventing the electrolyte 3 enclosed between the first substrate 1 and the second substrate 8 from leaking to the outside. The protective member 11 is bonded to the other main surface of the second substrate 8 by the sealing member 10 so as to close the injection hole 9.

The sealing member 10 is a material having high corrosion resistance to the electrolyte 3, and a metal material, a resin material, or a glass material is used. Examples of the metal material include materials such as indium, zinc, gallium, silver, tin, aluminum, lead, bismuth, copper, and antimony. These materials are used alone or as two or more kinds of compounds or a mixture. Examples of the resin material include polyethylene, modified polyethylene, maleic acid-modified polyethylene, polypropylene, modified polypropylene, maleic acid-modified polypropylene, ionomer resin, fluororesin, butyl resin, epoxy resin, or acrylate resin. Moreover, these resin materials may contain a filler etc. as needed from a viewpoint of improving mechanical strength. As the glass material, glass having a softening point lower than that of the second substrate 8 is used. For example, lead glass, bismuth glass, borosilicate glass, phosphate glass, zinc borosilicate glass. , SiO _x —BiO _y —MO _z- based glass (including glass composed of SiO ₂ , Bi ₂ O ₃ and other metal oxides), BO _x —BiO _y —MO _z- based glass (B ₂ O ₃ , Including glass composed of Bi ₂ O ₃ and other metal oxides), SiO _x —CaO _y —Na (K) O _z —MO _w- based glass (SiO ₂ , CaO, Na (K) ₂ O and others) Or a glass having a composition of a metal oxide of PO _x -MgO _y (including glass having a composition of P ₂ O ₅ , MgO and other metal oxides). The softening point of the glass material used for the sealing member 10 is preferably 300 ° C to 600 ° C. The softening point of the glass material used for the sealing member 10 can be adjusted by the material composition ratio.

  The glass material used for the sealing member 10 may include a light absorber so that the laser light can be efficiently absorbed. Thereby, the sealing member 10 can be heated by the laser light, and the sealing member 10 can be melted by the heat, and the injection hole 9 can be easily sealed by the sealing member 10. Examples of such a light absorber include materials such as chromium, iron, nickel, cobalt, manganese, copper, and carbon, and these are used as a simple substance, an oxide, or a compound of two or more of these.

  Moreover, when the glass frit itself of the sealing member 10 has a light absorption capability with respect to the laser beam, it may be used alone. The material is preferably a glass frit containing a laser absorbing component and a glass component. This laser-absorbing component plays a role of efficiently melting and sintering the glass frit by selectively absorbing laser light and converting the energy into heat. The laser absorbing component is preferably melted as a part of the matrix forming the glass frit, but may be segregated in the matrix. Further, if the thermal expansion coefficient of the glass frit is close to the thermal expansion coefficient of the second substrate 8 or 1 to 20% lower, the occurrence of defects such as cracks can be reduced.

  Further, the protective member 11 is for further enhancing the sealing action of the sealing member 10, and a material made of the same material as the sealing member 10 in the form of a film is used.

  In addition, in sectional drawing which showed 1st Embodiment which concerns on the photoelectric conversion apparatus of this invention of FIG. 1, although the sealing member 10, the protection member 11, and the injection hole 9 were provided, the sealing member 10, protection member 11 and the injection hole 9 are not provided, and the electrolyte 3 is applied onto the first or second substrate and sealed by the first substrate 1, the second substrate 8, the frame portion 6, and the bonding portion 5. Also good. Further, after applying the electrolyte 3 having a high viscosity or the quasi-solid electrolyte 3 onto the first or second substrate by a printing method, the first substrate 1, the second substrate 8, the frame portion 6, and the bonding You may seal by the part 5. FIG.

  Next, another embodiment of the present invention will be described.

  FIG. 2 is a cross-sectional view showing a second embodiment according to the photoelectric conversion device of the present invention. The same reference numerals are used for the same components as in the first embodiment, and the description thereof is omitted. The photoelectric conversion device X ′ according to the second embodiment is different from the photoelectric conversion device X according to the first embodiment in that the upper and lower sides of the joint portion 5 are stacked by the frame portion 6.

  In the photoelectric conversion device X ′, by making the structure of the side wall part vertically symmetric, the stress around the side wall part can be made symmetric, and the sealing reliability can be improved. Moreover, by comprising the junction part 5 and the frame part 6 with the same kind of material, the wettability with respect to the upper and lower frame parts 6 of the junction part 5 is improved, and the reliability of sealing can be improved. In the case where a metal is used for the joint 5 and a plurality of first electrodes 2 or second electrodes 7 are provided on the first substrate 1 or the second substrate 8, respectively, the metal joint 5 may cause a short circuit, the frame 6 functions as an insulating layer.

  FIG. 3 is a cross-sectional view showing a third embodiment of the photoelectric conversion device of the present invention. The same reference numerals are used for the same components as in the first embodiment, and the description thereof is omitted. The photoelectric conversion device X ″ according to the third embodiment is different from the photoelectric conversion device X according to the first embodiment in that a resin material 12 is provided inside the frame portion 6 and the joint portion 5.

  In the photoelectric conversion device X ″, since the electrolyte 3 does not have to be in direct contact with the frame portion 6 and the joint portion 5, the frame portion 6 and the joint portion 5 are corroded by the electrolyte 3, and the sealing performance is deteriorated. It is possible to suppress the deterioration of characteristics of the photoelectric conversion device. Further, due to the adhesive force and stress absorption of the resin material 12, it is possible to suppress deterioration in strength of the frame portion 6 and the joint portion 5, suppress deterioration in sealing performance, and suppress deterioration in characteristics of the photoelectric conversion device. In addition, the resin material 12 can suppress leakage of the electrolyte 3, intrusion of moisture in the outside world, and intrusion of oxygen in the outside world, thereby suppressing deterioration in characteristics of the photoelectric conversion device.

  The resin material 12 is a material having high corrosion resistance to the electrolyte 3. Examples of the resin material 12 include polyethylene, modified polyethylene, maleic acid-modified polyethylene, polypropylene, modified polypropylene, maleic acid-modified polypropylene, ionomer resin, fluororesin, butyl resin, epoxy resin, or acrylate resin. Moreover, these resin materials may contain a filler etc. as needed from a viewpoint of improving mechanical strength.

Examples of the photoelectric conversion device of this embodiment will be described below. A photoelectric conversion device X having the configuration shown in FIG. 1 was produced as follows.
<Preparation of dye-sensitized solar cell>
As the first substrate 1, a transparent conductive layer (first electrode 2) composed of a SnO ₂ : F layer (F-doped SnO ₂ layer (FTO layer)) having a sheet resistance of 10Ω / □ (square) is patterned by a laser ablation method. A formed soda-lime glass substrate (translucent substrate 1) was prepared.

Next, a semiconductor layer 4 made of porous titanium oxide (not shown), which is a part of a photoelectric conversion body containing an electrolyte, was formed on the transparent conductive layer 2. The porous semiconductor layer was formed as follows. First, acetylacetone was added to anatase powder of titanium oxide (TiO ₂ ) and then kneaded with deionized water to prepare a titanium oxide paste stabilized with a surfactant. The produced paste was pattern-printed on the transparent conductive layer 2 composed of the FTO layer by screen printing, and baked at 500 ° C. for 30 minutes in the atmosphere to form a porous semiconductor layer 4.

  Next, the first substrate 1 on which the semiconductor layer 4 is formed is immersed in an ethanol solution in which a black dye (Ru complex) (manufactured by Solaronics, product name “black dye”) is dissolved. A dye (not shown) was adsorbed. Thereafter, excess dye was washed with a pure ethanol solution and dried.

  On the other hand, a soda-lime glass substrate having a Pt layer (second electrode 7) (not shown) formed by sputtering with a thickness of 5 nm was prepared as a support substrate 8 for the counter electrode. Further, the support substrate 8 was previously provided with injection holes 9 for dye circulation and electrolyte solution injection.

  Next, a paste made of borosilicate glass frit was pattern-printed on the electrode 7 by a screen printing method and baked in the atmosphere at 500 ° C. for 30 minutes to form the frame 6. Next, a paste made of a glass frit of bismuth acid-based glass was pattern-printed on the frame portion 6 by screen printing, and baked at 450 ° C. for 30 minutes in the air to form the joint portion 5.

Next, the translucent substrate 1 on which the porous semiconductor layer (TiO ₂ ) is formed and the electrode surface of the support substrate 8 on which the electrode 7 is formed face each other, the bonding portion 5 and the transparent electrode 2 are brought into close contact with each other, Through the transparent substrate 1, the semiconductor laser beam was irradiated to the bonding portion 5 and heated to seal the bonding portion 5 and the transparent electrode 2.

Next, a methoxypropionitrile solution containing iodine (I ₂ ), lithium iodide (LiI), and an additive such as an imidazolium salt and imidazole was injected from the injection hole 9 to form an electrolyte 3. .

  Next, a paste made of glass frit was pattern-printed on the protective member 11 of the soda lime glass substrate by a screen printing method, and baked at 500 ° C. for 30 minutes in the atmosphere to form the sealing member 10. Next, the sealing member 10 and the other main surface of the support substrate 8 are brought into close contact so as to seal the injection hole 9, and the semiconductor laser light is irradiated to the sealing member 10 through the protective member 11 of the soda lime glass substrate. The sealing member 10 and the support substrate 8 were sealed by heating, and the photoelectric conversion device X was formed.

  In 85 degreeC and 85% RH, the photoelectric conversion apparatus X of the said Example did not generate | occur | produce leakage of electrolyte solution even in 1000 hours, and was able to maintain the photoelectric conversion characteristic.

It is sectional drawing which shows 1st Embodiment of the photoelectric conversion apparatus which concerns on this invention. It is sectional drawing which shows 2nd Embodiment of the photoelectric conversion apparatus which concerns on this invention. It is sectional drawing which shows 3rd Embodiment of the photoelectric conversion apparatus which concerns on this invention.

Explanation of symbols

X, X ′, X ″: photoelectric conversion device 1: first substrate 2: first electrode 3: electrolyte 4: semiconductor layer 5: junction 6: frame 7: second electrode 8: second Substrate 9: Injection hole 10: Sealing member 11: Protection member 12: Resin material

Claims (7)

A translucent substrate having a first major surface;
A support substrate having a second main surface opposite to the first main surface;
A dye-sensitized photoelectric conversion body provided between the first main surface and the second main surface;
A side wall that surrounds the photoelectric conversion body and joins the translucent substrate and the support substrate;
The side wall portion includes a frame portion provided on at least one of the translucent substrate or the support substrate, and a joint portion laminated on the frame portion and having a larger absorption coefficient for laser light than the frame portion. and it is,
The softening point of the frame part is lower than the softening point of the translucent substrate provided with the frame part or the support substrate provided with the frame part,
The photoelectric conversion device , wherein the translucent substrate and the support substrate are bonded via the side wall portion by irradiating the bonding portion with the laser beam .   The photoelectric conversion device according to claim 1, wherein the frame portion is provided on each of the translucent substrate and the support substrate.   The photoelectric conversion device according to claim 1, wherein a softening point of the joint portion is lower than a softening point of the frame portion. The junction photoelectric conversion device according to any one of claims 1 to 3, characterized in that it comprises a light absorber. The distance between the inner surface on the photoelectric conversion body side in the joint and the outer surface on the opposite side of the photoelectric conversion body is the distance between the inner surface on the photoelectric conversion body side in the frame and the outer surface on the opposite side of the photoelectric conversion body. the photoelectric conversion device according to any one of claims 1 to 4, characterized in smaller than. The frame portion is provided on the translucent substrate, an electrode is formed on the first main surface, and the electrode extends to an interface between the frame portion and the translucent substrate. the photoelectric conversion device according to any one of claims 1 to 5, characterized in. The frame portion is provided on the support substrate, an electrode is formed on the second main surface, and the electrode extends to an interface between the frame portion and the translucent substrate. The photoelectric conversion device according to any one of claims 1 to 5 .

Images