JP2010231912A - Manufacturing method of photoelectric conversion element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a photoelectric conversion element capable of sealing with high durability, even when a resin film is used for an action pole substrate. <P>SOLUTION: At least an action pole substrate (1) is constituted of a sheet film made of synthetic resin; a glass shaped film (2) is formed on an inner face of the sheet/film; and as for the glass shaped film (2) a bonding face of a sealing member (10) is bonded to at least the glass-shaped film (2) of the action pole substrate (1). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  In the present invention, a transparent conductive film on a transparent working electrode substrate, a working electrode having a photocatalytic film thereon, and a counter electrode having at least a conductive member on the counter electrode substrate are arranged in a facing manner at a predetermined interval, The present invention relates to a method for producing a photoelectric conversion element in which an electrolyte is disposed.

  Throughout the present specification and claims, the internal / external relationship is based on the structure of the photoelectric conversion element, with the inside being the inside and the outside being the outside.

  In general, photoelectric conversion elements such as dye-sensitized solar cells form a transparent conductive film on a transparent working electrode substrate such as a glass plate, and a photocatalytic film made of a metal oxide such as titanium oxide on the transparent conductive film. The working electrode formed by adsorbing a photosensitizing dye such as a ruthenium complex on the same film and the counter electrode formed by forming a conductive film on the counter electrode substrate are arranged opposite to each other, and an iodine-based electrolyte or the like is disposed between both electrodes. The thing which intervened the electrolyte layer which consists of is known.

  In the photoelectric conversion element having such a configuration, a sealing technique is important in order to extend the life while maintaining the battery performance. For example, various research and developments such as a sealing structure and a sealing material have been performed so that the electrolyte in the photoelectric conversion element does not leak to the outside (for example, Patent Document 1).

JP 2007-194075 A

  As a transparent working electrode substrate, a flexible resin substrate made of an organic substrate made of a synthetic resin such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN) is used instead of the conventional glass substrate or other inorganic substrate. A type of photoelectric conversion element has been developed. In this case, the substrate made of the resin film has a problem that the adhesive strength with a normal resin-based sealing material is not sufficient, and the durability is poor even if it can be sealed.

  Further, when glass frit is used as the sealing material, the sealing durability is relatively improved as compared with the resin-based sealing material, but it is necessary to heat and melt it at a high temperature of about 300 to 600 ° C. There is a problem that it cannot be applied to the resin film substrate.

  Therefore, the present invention provides a method for producing a photoelectric conversion element capable of highly durable sealing even when a resin film is used for the working electrode substrate.

In the first aspect of the invention, the transparent conductive member on the inner surface of the transparent working electrode substrate, the working electrode having the photocatalytic film on the inner surface, and the counter electrode having at least the conductive member on the inner surface of the counter electrode substrate are interposed via the sealing member. A method for producing a photoelectric conversion element, which is arranged in an opposing manner and in which an electrolyte is arranged between both electrodes,
Of the working electrode substrate and the counter electrode substrate, at least the working electrode substrate is composed of a synthetic resin sheet / film, a glassy film is formed on the inner surface of the sheet / film, and at least the glassy film of the working electrode substrate. The method for manufacturing a photoelectric conversion element is characterized in that surfaces to be bonded of the sealing member are bonded to each other.

  The invention according to claim 2 is the method for producing a photoelectric conversion element according to claim 1, wherein the inner surface of the glassy film is uneven.

  The invention according to claim 3 is characterized in that the glassy film is formed by applying a sol made of a silica compound to the inner surface of the sheet / film, drying and firing, and forming the glassy film. It is a manufacturing method of this photoelectric conversion element.

  According to the invention of claim 1, at least the working electrode substrate is composed of a synthetic resin sheet / film, a glassy film is formed on the inner surface of the sheet / film, and at least the glassy film of the working electrode substrate is By joining the surfaces to be joined of the sealing member, the affinity (sealing force) with the resin-based sealing material is improved without being heated and melted at a high temperature as in the case of sealing with a conventional glass frit. .

  Therefore, when producing a solar cell composed of a photoelectric conversion element, sealing can be easily and firmly performed, and moisture and impurities from the outside of the photoelectric conversion element can be reliably prevented from entering the solar cell. It is possible to extend the life while maintaining high power generation efficiency. In addition, since the glassy film has the effect of confining the light beam inside by scattering the light beam from the outside of the photoelectric conversion element (confinement effect), the durability and power generation efficiency of the solar cell can be further enhanced.

  According to the invention of claim 2, by making the inner surface of the glassy film uneven, it is possible to take in light incident from a wide range of directions into the photocatalyst layer in the photoelectric conversion element. Can be improved.

  According to invention of Claim 3, the said effect is further heightened.

It is a vertical sectional view showing a photoelectric conversion element. It is a vertical sectional view showing an example in which a glassy film is formed on the inner surface of a working electrode substrate composed of an uneven sheet / film. It is a top view which shows the modification of an uneven | corrugated sheet | seat / film.

  As a material for the working electrode substrate, PET (polyethylene terephthalate) is preferable, but PEN (polyethylene naphthalate) film, polyester, polycarbonate, polyolefin and the like may be used.

The thickness of the working electrode substrate is preferably several tens of μm to 1 mm.
The material of the counter electrode substrate may be the same as that of the working electrode substrate, but may be other insulating materials. In the case where it is not necessary to mainly incorporate light rays into the element on the working electrode side and to incorporate light rays into the element on the counter electrode side, the counter electrode substrate does not need to be transparent.

  The thickness of the counter electrode substrate is preferably several tens of μm to 1 mm.

The means for forming a glassy film on the surface of the working electrode substrate (ie, the inner surface) is not particularly limited, but a coating solution containing silicate, alumina silicate, etc. is applied to the surface of the working electrode substrate, and the coating film is dried at room temperature. The glassy film can be formed by firing at 150 ° C. or lower, preferably 120 ° C. to 150 ° C.

The raw material of the glassy film is not particularly limited as long as it is a glass-based coating material using silicon as a raw material, and is a silicone-based material obtained by combining a glass system using silicon as a raw material and a fluorine system using petroleum as a raw material. It may be a material.

Also, the glass-like film, a coating solution containing an inorganic polymer (perhydropolysilazane [PHPS], etc.) which are soluble in an organic solvent, coated, were obtained by firing polysilazane silica (silicon oxide SiO ₂₎ It may be converted to In this case, since the coated surface is covered with a silica glass material and the surface property is like glass, the bonding force with the sealing member is improved.

  The thickness of the glassy film is preferably 1 sub μm to 20 μm. As the application method, application by spin coating or squeegee method, electrostatic application (electrostatic spray) or ultrasonic spray is preferable. In electrostatic coating and ultrasonic spraying, a sol composed of a silica compound can be applied in the form of a mist on the inner surface of the working electrode substrate, so that a glassy film can be formed that matches the shape and dimensions of the irregularities of the working electrode substrate, which will be described later. .

  In the case of electrostatic coating, it is preferable that the distance between the spray nozzle and the resin substrate is 50 to 2000 mm, and the coating is performed by applying a voltage of 10 to 30 kV between the nozzle and the electrode under the substrate.

As the sol composed of a silica compound, for example, a material obtained by adding ethanol, water, hydrochloric acid or the like to tetraethoxysilane (Si (C ₂ H ₅ ) ₄ ) which is a metal alkoxide (silicon alkoxide) is used.

  When a glassy film is formed also on the inner surface of the counter electrode substrate, the forming means may be the same as described above.

  The inner surface of the glassy film, that is, the surface on which the glassy film is to be formed is preferably uneven. The method of making the inner surface of the glassy film uneven is (i) a method of forming a glassy film having a uniform thickness along the uneven part shape after forming the inner surface of the working electrode substrate into an uneven shape, ii) A method of forming a glassy film on the flat inner surface of the working electrode substrate so that the surface thereof is uneven.

  In the method (i), the inner surface of the sheet / film, which is a material of the transparent working electrode substrate, is made uneven. When the light beam is incident from the counter electrode substrate side, it is preferable that the inner surface of the sheet / film, which is a material of the transparent counter electrode substrate, is also uneven. Even when light is not incident from the counter electrode substrate side (when the counter electrode substrate is not transparent), it is preferable to make the inner surface of the sheet / film, which is the material of the counter electrode substrate, uneven. Due to the concavo-convex surface of the counter substrate, it is possible to expect a confinement effect of light rays that are incident from the working electrode substrate side through the photocatalyst layer and reach the counter electrode substrate.

  In the method (ii), a glassy film is formed with a uniform thickness on the flat inner surface of the working electrode substrate, and a glassy film is further formed only on a portion that becomes a convex portion on the glassy film. Alternatively, the concave portion is formed by performing groove processing on the glassy film formed with the uniform thickness.

  The height from the valley bottom to the peak of the concavo-convex portion is preferably not less than twice the diameter of the photocatalyst particles (about 40 nm) and not more than half the thickness of the photocatalyst film (about 10 to 15 μm).

  This is because if the height is less than twice the diameter of the photocatalyst particle, the concave portion is filled with the photocatalyst particle, and the confinement effect cannot be obtained sufficiently. Since it does not reach the depth of the layer, the efficiency is lowered, which is not preferable.

  The shape (pattern) of the concavo-convex portion is not particularly limited. However, since the life of electrons emitted from the photosensitizing dye is short, if the groove interval is too large, the electrons disappear in the middle, and the power generation efficiency decreases. If the groove interval is too narrow, the aperture ratio of the solar cell tends to decrease (because the area capable of generating power decreases), and the power generation efficiency tends to decrease. Therefore, the shape (pattern) is formed in consideration of this point.

  Examples of the shape of the uneven portion include those shown in FIG. 3A, 3B, and 3C, (21) is a concave portion, and (22) is a convex portion.

In the working electrode, a transparent conductive film is formed on the inner surface of the glassy film in order to improve conductivity. There are various methods for forming the transparent conductive film, such as ionization vapor deposition and CVD, and it is not particularly limited. As a metal target in the sputtering method, tin-doped indium oxide (ITO), fluorine-doped tin oxide (FTO), tin oxide (SnO ₂ ), indium zinc oxide (IZO), and zinc oxide (ZnO) of a transparent conductive film are used. Materials such as In—Sn alloy, Zn, In—Zn alloy, Sn, Ga—Zn alloy, Al—Zn alloy, etc. are preferably used. There is no particular limitation. The thickness of the transparent conductive film is preferably several tens to several hundreds nm.

  Even with the counter electrode, a glassy film may be formed on the inner surface of the substrate and a conductive film may be formed thereon. The counter electrode conductive film may be composed of platinum, polyethylenedioxythiophene (PEDOT), or the like.

A photocatalytic film is formed on the transparent conductive film. For example, i) a method in which a paste containing photocatalyst particles (metal oxide particles) is applied on a transparent conductive film, dried and optionally fired, or ii) a metal oxide sol is applied on the transparent conductive film It is performed by a method of applying electrostatically, drying, and optionally firing.

The photocatalytic particles are made of a metal oxide such as titanium oxide (TiO ₂ ), tin oxide (SnO ₂ ), tungsten oxide (WO ₃ ), zinc oxide (ZnO), or niobium oxide (Nb ₂ O ₅ ). Furthermore, it is preferable to mix photocatalyst particles having a particle size of several hundred nm.

  In the method i), the photocatalyst-containing paste may be one obtained by adding photocatalyst particles to pure water, ethanol, propanol, t-butanol or the like.

In the method ii), the electrostatic coating apparatus is on the negative side and the transparent conductive film that is the object to be coated is on the positive side, a high voltage is applied between them to form an electrostatic field, which is sprayed from the spray nozzle of the electrostatic coating apparatus. The metal oxide sol is charged to the negative side and coated on the inner surface of the transparent conductive film. In this case, laser irradiation may be performed while electrostatic coating, and the drying and baking may be performed simultaneously. The electrostatic coating apparatus is not limited to the above configuration as long as it can apply the metal oxide sol onto the transparent conductive film. The laser is preferably visible light region to near infrared region (700 nm to 1100 nm), specifically, Nd: YAG laser (1064 nm), Nd: YVO4 laser (1064 nm), or TI: sapphire laser (650-1100 nm), A tunable laser such as a Cr: LiSAF laser (780-1010 nm), an alexandrite laser (700-820 nm), or a CO ₂ laser is applicable.

  Examples of the metal compound used as a starting material for the metal oxide sol include metal alkoxides, metal acetylacetonates, metal carboxylates, and metal inorganic compounds such as metal nitrates, oxychlorides, and chlorides. Can be mentioned.

  The metal oxide is preferably titanium oxide, and other examples include tin oxide, tungsten oxide, zinc oxide, and niobium oxide.

  As an example of using titanium oxide, as metal alkoxide, titanium tetramethoxide, titanium ethoxide, titanium isopropoxide, titanium butoxide, etc., as metal acetylacetonate, as titanium acetylacetonate, as metal carboxylate , Titanium carboxylate, titanium nitrate, titanium oxychloride, titanium tetrachloride and the like.

  Further, the metal compound includes water, methanol, ethanol, 1-propanol, isopropyl alcohol, 1-butanol, 2-butanol, isobutanol, t-butanol, 1-pentanol, 2-pentanol, 3-pentanol and the like. By adding a solvent, acid or ammonia, and other additives, sol-formation and gelation are performed.

  In the methods i) and ii), drying is performed at room temperature for about 5 to 15 minutes. Firing is performed at a temperature of 120 to 150 ° C. for about 10 to 30 minutes.

  The thickness of the photocatalyst film is preferably 5 to 20 μm.

  Next, it is preferable to irradiate the photocatalytic film with a laser from the working electrode substrate side. This laser may be the same as described above.

  Thereafter, the photosensitizing dye is adsorbed on the photocatalyst film. Adsorption of the photosensitizing dye is performed, for example, by immersing a working electrode having a photocatalyst film in an immersion liquid containing the photosensitizing dye to adsorb the dye on the surface of the photocatalyst film. After immersion, it is preferable to perform drying and further firing. Photosensitizing dyes include, for example, ruthenium complexes and iron complexes having a ligand containing a bipyridine structure, a terpyridine structure, etc., porphyrin-based and phthalocyanine-based metal complexes, and organic dyes such as eosin, rhodamine, merocyanine, and coumarin. It may be.

  To form a photocatalyst film dyed with a photosensitizing dye, for example, a paste containing a photosensitizing dye and photocatalyst particles is applied to the inner surface of the transparent conductive film, and the photocatalyst particles dyed with the dye are transparent by drying. You may make it carry | support to an electrically conductive film.

  The glassy film formed here has an effect of preventing corrosion of the counter electrode substrate by an electrolyte such as iodine in addition to the effect of the working electrode.

  In the photoelectric conversion element, a transparent conductive member on a transparent working electrode substrate, a working electrode having a photocatalyst film thereon, and a counter electrode having at least a conductive member on a counter electrode substrate are arranged at a predetermined interval to face each other. It is mainly configured by disposing an electrolyte between them.

As the electrolyte, for example, an iodine-based electrolyte is used. Specifically, an electrolyte component such as iodine, iodide ion, or tertiary butyl pyridine is dissolved in an organic solvent such as ethylene carbonate or methoxyacetonitrile. Is exemplified. The electrolyte is not limited to an electrolyte and may be a solid electrolyte. The solid electrolyte, for example, is illustrated DMPImI (dimethylpropyl imidazolium iodide) is, in addition, LiI, NaI, KI, CsI, metal iodide such as CaI _2, and tetraalkylammonium iodide and quaternary ammonium compounds A combination of iodides such as the iodine salts of I ₂ and I ₂ ; bromides such as bromides of metal bromides such as LiBr, NaBr, KBr, CsBr, CaBr ₂ and quaternary ammonium compounds such as tetraalkylammonium bromide and Br _2. And the like can be used as appropriate.

  In the photoelectric conversion element, for example, a transparent conductive member for a working electrode, a conductive member for a counter electrode, a collecting electrode, an electrolyte layer, and a photocatalyst film are arranged at a predetermined interval between a square transparent working electrode substrate and a square counter electrode substrate. In this case, the working electrode and the counter electrode may be connected in series or in parallel. In either case, the electrolyte layer and the photocatalyst film are separated from each other by a sealing member that serves as a separator. In the case of series connection, a gap is formed between the adjacent conductive electrode for the working electrode, the conductive member for the counter electrode, and the collecting electrode, and the adjacent transparent conductive member for the working electrode and the conductive member for the counter electrode are conductors. Connected by. In the case of parallel connection, the transparent conductive member for the working electrode, the conductive member for the counter electrode, and the current collecting electrode have a shape with no gap between adjacent ones.

  The working electrode may be a transparent conductive film formed on a working electrode substrate (ITO glass, FTO glass, etc.), a metal plate or a metal foil (aluminum, copper, tin, titanium, etc.), etc. A transparent conductive film formed on a counter electrode substrate or a conductive film such as platinum or PEDOT formed on the inner surface of a metal sheet such as aluminum, copper, or tin may be used.

  In order to assemble the photoelectric conversion element, for example, the working electrode and the counter electrode are aligned to face each other at intervals of several μm to several tens of μm, and both electrodes are sealed with a heat-sealing film or a sealing member. Alternatively, the electrolyte is injected from holes or gaps provided in advance in the working electrode or the like. When a solid electrolyte is used, the photocatalyst film and the electrolyte layer may be stacked so as to be sandwiched between the two electrodes, and the peripheral portions thereof may be heat bonded. Heating may be performed by a mold, or may be performed by irradiation with an energy beam such as plasma (having a long wavelength), microwave, visible light (600 nm or more), or infrared light.

  The sealing member serving as a separator that partitions the electrolyte layer and the photocatalyst film between adjacent ones may be made of, for example, a thermosetting resin.

  Next, in order to explain the present invention specifically, some examples of the present invention will be given.

Example 1
In FIG. 1, a sol (tetraethoxysilane (Si (C ₂ H ₅ ) ₄ ) made of a silica compound is formed on the entire surface (ie, the inner surface) of a 100 μm-thick biaxially stretched PET film to be a transparent working electrode substrate (1). 25g, 37.6g of ethanol, 23.5g of water, 0.3g of hydrochloric acid) were applied by the spray electrostatic coating method, and the resulting coating film was dried at room temperature and then baked at 150 ° C to form a glassy film consisting of silicate (2 ) Was formed. Thereafter, a transparent conductive film (3) having a thickness of 150 nm made of tin-added indium oxide (ITO) was formed on the inner surface of the glassy film (2). This was cut into a predetermined shape so that the transparent conductive film (3) functions as a working electrode of the dye-sensitized solar cell. Furthermore, a paste containing titanium oxide particles as photocatalyst particles (ethanol and water added with titanium oxide) is applied, dried at room temperature for 15 minutes, baked at 150 ° C for 15 minutes, and transparent conductive A photocatalytic film (4) having a thickness of 10 μm was formed on the film (3). Thus, the working electrode (5) composed of the working electrode substrate (1), the glassy film (2), the transparent conductive film (3) and the photocatalytic film (4) was constructed.

  Working electrode (5) is an immersion liquid containing a photosensitizing dye (ruthenium complex (N719, molecular weight 1187.7 g./mol) dissolved in t-butanol: acetonitrile (volume ratio 1: 1). : 0.3 mM) for 40 minutes at a temperature of 40 ° C., the same dye was adsorbed on the surface of the photocatalyst film (4).

  Similarly to the working electrode substrate (1), the counter electrode substrate (6) was made of a biaxially stretched PET film, and was obtained by applying a sol made of a silica compound to the entire surface (that is, the inner surface) by a spray electrostatic coating method. The coating film was dried at room temperature and then baked at 150 ° C. to form a glassy film (7) made of silicate. Thereafter, a 150 nm thick conductive film (8) made of PEDOT was formed on the inner surface of the glassy film (7). This conductive film (8) was cut into a predetermined shape so as to function as a working electrode of the dye-sensitized solar cell. Thus, a counter electrode (9) composed of a counter electrode substrate (6), a glassy film (7), and a conductive film (8) was constructed.

  As shown in FIG. 1, the working electrode (5) and the counter electrode (9) were arranged so as to face each other at an interval of 15 μm with each conductive film inside. The lower end surface of the lower sealing member (10) is joined to the upper surface (inner surface) of the working electrode glass film (2), and the upper end surface of the lower sealing member (10) is connected to the transparent conductive film of the counter electrode (9) ( Joined to 8). Further, the upper end surface of the upper sealing member (11) is bonded to the lower surface (inner surface) of the counter electrode glassy film (7), and the lower end surface of the upper sealing member (11) is connected to the transparent conductive film (5) Joined to 2). Thereafter, an electrolyte solution (12) was formed by filling the space between both electrodes with an electrolytic solution. (13) is the inter-electrode wiring.

  Thus, a dye-sensitized solar cell composed of the photoelectric conversion element shown in FIG. 1 was produced.

Example 2
In FIG. 2, the working electrode substrate (1) having the surface (inner surface) having the unevenness shown in FIG. 3 (a) is used, and the glassy film (2) is formed on the uneven surface (inner surface) with a uniform thickness. . Other configurations are the same as those of the first embodiment.

(1) is the working electrode substrate
(2) is a glassy membrane
(3) is transparent conductive film
(4) is a photocatalytic film
(5) is the working electrode
(6) is the counter electrode substrate
(7) is a glassy membrane
(8) is a transparent conductive film
(9) is the counter electrode
(10) is the lower sealing member
(11) is the upper sealing member
(12) is the electrolyte layer
(21) is a recess
(22) is convex

Claims (3)

A transparent conductive member on the inner surface of the transparent working electrode substrate, a working electrode having a photocatalyst film on the inner surface thereof, and a counter electrode having at least a conductive member on the inner surface of the counter electrode substrate are disposed opposite to each other with a sealing member therebetween. A method for producing a photoelectric conversion element in which an electrolyte is disposed between
Of the working electrode substrate and the counter electrode substrate, at least the working electrode substrate is composed of a synthetic resin sheet / film, a glassy film is formed on the inner surface of the sheet / film, and at least the glassy film of the working electrode substrate. A method for producing a photoelectric conversion element, comprising joining the surfaces of the sealing member to be joined to each other. The method for manufacturing a photoelectric conversion element according to claim 1, wherein an inner surface of the glassy film is uneven. The method for producing a photoelectric conversion element according to claim 1, wherein the glassy film is formed by applying a sol made of a silica compound to the inner surface of the sheet / film, drying and firing.

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