JP5577519B2 - Photoelectric conversion element - Google Patents

Description

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

  The dye-sensitized solar cell is called a wet solar cell or a Gretzel battery, and is characterized in that it has an electrochemical cell structure typified by an iodine solution without using a silicon semiconductor. For example, a porous semiconductor layer such as a titania layer formed by baking a titanium dioxide powder or the like on a transparent conductive glass plate (transparent substrate on which a transparent conductive film is laminated) and adsorbing a dye to this, and a conductive glass plate (conductive A simple structure in which an iodine solution or the like is disposed as an electrolytic solution between counter electrodes made of a conductive substrate).

In dye-sensitized solar cells, the light adsorbed from the transparent conductive glass plate surface, which is the light-receiving surface, is absorbed by the dye adsorbed on the porous semiconductor layer, causing electronic excitation, and the excited electrons are transferred to the semiconductor. It moves and is further guided to the conductive glass. Electrons that have moved from the conductive glass to the counter electrode via a load are guided to the dye via an electrolyte such as iodine.
Dye-sensitized solar cells are currently reported to have a solar conversion efficiency of about 11%. However, further improvement in efficiency is required, and studies have been made from various viewpoints.

One of them is improvement of light absorption efficiency.
For example, in order to improve the light absorption efficiency of the porous semiconductor layer that adsorbs the dye, the mixed fine particles in which fine particles having a high light diffusing ability are mixed with oxide fine particles having a particle diameter of 0.1 nm to 10 μm are fired. By using an oxide semiconductor film formed as described above, it has been studied to increase the internal mounting area and increase the light diffusing ability to reduce the amount of light that is transmitted without being absorbed by the dye (see Patent Document 1).
However, an oxide semiconductor film including fine particles having a high light diffusing capacity with a particle size of, for example, about 150 nm has a small surface area per volume (specific surface area), and therefore, the amount of dye adsorbed may be reduced, leading to a reduction in efficiency. .
In order to improve the light absorption efficiency, for example, it is conceivable to increase the thickness of the porous semiconductor layer that has adsorbed the dye. However, simply increasing the thickness of the porous semiconductor layer not only increases the efficiency, but also reduces the efficiency.

  On the other hand, in order to optically improve the amount of received light, it is conceivable that light having a high optical density is guided to the power generation part, for example, by condensing with an optical lens or a mirror. However, when the size of the solar cell is increased, these optical members are a heavy burden in terms of equipment costs.

One of the causes of the low light absorption efficiency is that a dye that can absorb light in a wide wavelength range from 400 nm to a wavelength of near infrared or higher with high efficiency has not been obtained so far. For this reason, light that has not been absorbed by the porous semiconductor layer on which the dye is adsorbed becomes an absorption loss as it is.
Focusing on this point, various so-called tandem dye-sensitized solar cells in which a porous oxide semiconductor layer carrying a dye is provided in two stages in series with respect to the traveling direction of incident light have been studied (for example, Patent Document 2).
However, even for tandem dye-sensitized solar cells, it may require further improvement in light absorption efficiency, the manufacturing method may be complicated, or there may be inconvenience when the battery is enlarged, There seems to be much room for further improvement.

In addition, in view of the fact that the amount of power generated is not stable because the amount of light and the incident angle of sunlight, which is the energy source of the solar cell, changes depending on the time and season, a transparent conductive layer and a dye-sensitized porous There has been proposed a dye-sensitized photoelectric conversion element having a structure in which a semiconductor layer and an electrolyte layer are sequentially provided, and a counter electrode is inserted at the center of the tube (see Patent Document 3).
According to this dye-sensitized photoelectric conversion element, it is said that a change in the amount of power generation with respect to the incident angle of light can be greatly reduced, and a dye-sensitized photoelectric conversion element having high durability can be provided.
However, this dye-sensitized photoelectric conversion element has a surface that is incompatible with the conventional idea of arranging the light receiving surface in the vertical direction from the horizontal surface on the ground so that sunlight with high light energy density can be received. Seems to be. In particular, it is not necessarily suitable for increasing the size of the apparatus by arranging a large number of dye-sensitized photoelectric conversion elements.

JP 2002-93476 A JP 2008-53042 A JP 2008-53042 A

  The problem to be solved is that all of the conventional dye-sensitized solar cells have one or both of the problems that the manufacturing method is complicated and there is a lot of room for improvement toward the enlargement of the apparatus. It is what you have.

The photoelectric conversion device according to the present invention has a light-receiving surface on one end surface of a columnar transparent core member or a bottom surface of a weight-shaped transparent core member , and a porous semiconductor layer containing a dye on the side surface of the transparent core member, porous It is a dye-sensitized solar cell in which a conductive layer including a porous conductive metal layer, an electrolytic solution layer, and a catalyst layer is arranged in this order.

  The photoelectric conversion element according to the present invention preferably has two or more optical refractive indexes in which the columnar or weight-shaped transparent core member is stacked and arranged in a direction perpendicular to the axis of the transparent core member. The transparent core member portion is provided in the order of the transparent core member portion having a small light refractive index and the transparent core member portion having a large light refractive index from the axial center side of the transparent core member.

  Moreover, the photoelectric conversion element according to the present invention is preferably provided with a light-transmitting irregular reflection rough surface that irregularly reflects toward the inside of the transparent core member on the side surface of the columnar or weight-shaped transparent core member. It is characterized by becoming.

The photoelectric conversion element according to the present invention is preferably characterized in that a light scattering material is filled in the columnar or weight-shaped transparent core member.

  In the photoelectric conversion element according to the present invention, preferably, the porous semiconductor layer containing the dye is two or more porous semiconductor parts arranged in the axial direction of the transparent core member or in the direction perpendicular to the axial line. And different types of dyes are adsorbed to the two or more porous semiconductor portions.

  In the photoelectric conversion element according to the present invention, preferably, the two or more porous semiconductor portions are insulated from each other and provided with independent lead electrodes, respectively, and a conductive layer including the catalyst layer; It is electrically connected in parallel.

  In the photoelectric conversion element according to the present invention, the one end surface of the columnar transparent core member or the bottom surface of the weight-shaped transparent core member is the light receiving surface, and the photoelectric conversion cell constituent members are arranged on the side surface of the transparent core member. The entire side surface of the transparent core member into which light enters substantially functions as a light receiving portion. Thereby, the photoelectric conversion element suitable for the enlargement of an apparatus can be obtained with a simple manufacturing method.

It is side surface sectional drawing which looked at the dye-sensitized solar cell which concerns on the 1st example of this Embodiment from the longitudinal direction. It is the front view which looked at the dye-sensitized solar cell which concerns on the 1st example of this Embodiment from the paper surface left side in FIG. 1 (A). It is side surface sectional drawing which looked at the dye-sensitized solar cell which concerns on the 2nd example of this Embodiment from the longitudinal direction. It is side surface sectional drawing which looked at the dye-sensitized solar cell which concerns on the 3rd example of this Embodiment from the longitudinal direction. It is side surface sectional drawing which looked at the dye-sensitized photovoltaic cell which concerns on the 4th example of this Embodiment from the longitudinal direction. It is a figure which shows the cell member to be used about the preparation methods of the dye-sensitized solar cell of Example 1. FIG. It is a figure for demonstrating the process until it forms a titania layer about the preparation methods of the dye-sensitized solar cell of Example 1. FIG. It is a figure for demonstrating the process until it forms a coating layer about the preparation methods of the dye-sensitized solar cell of Example 1. FIG. It is a figure for demonstrating the process until forming Ti film | membrane about the preparation methods of the dye-sensitized solar cell of Example 1. FIG. It is a figure for demonstrating the process until obtaining a porous Ti layer about the preparation methods of the dye-sensitized solar cell of Example 1. FIG. It is a figure for demonstrating the process until it winds a porous film about the preparation methods of the dye-sensitized photovoltaic cell of Example 1. FIG. It is a figure for demonstrating the process until it plugs up with an epoxy resin about the preparation methods of the dye-sensitized photovoltaic cell of Example 1. FIG. It is a figure which shows the completed dye-sensitized solar cell about the preparation methods of the dye-sensitized solar cell of Example 1. FIG. 6 is a view for explaining a method for producing a dye-sensitized solar cell of Example 3. FIG. 6 is a diagram for explaining a method for producing a dye-sensitized solar cell of Example 4. FIG. 6 is a view for explaining a method for producing a dye-sensitized solar cell of Example 5. FIG. It is side surface sectional drawing which looked at the dye-sensitized solar cell which concerns on the 5th example of this Embodiment from the longitudinal direction. It is side surface sectional drawing which looked at the dye-sensitized photovoltaic cell which concerns on the modification of the 1st example of this Embodiment from the longitudinal direction.

  Embodiments of the present invention (hereinafter referred to as embodiments of the present invention) will be described below with reference to the drawings.

The basic configuration principle of the photoelectric conversion element according to the present embodiment is that the one end surface of the columnar transparent core member or the bottom surface of the weight-shaped transparent core member is the light receiving surface, and the photoelectric conversion cell configuration is formed on the side surface of the transparent core member. The members are arranged.
The photoelectric conversion cell constituent member can have an appropriate configuration. Examples of the photoelectric conversion part of the photoelectric conversion cell constituent member include single crystal silicon, polycrystalline silicon, thin film silicon, various thin films, and dye-sensitized materials.

The columnar shape of the transparent core member may be a columnar shape or may be a polygonal columnar shape. Further, the weight-like shape of the transparent core member may be a conical shape or a polygonal pyramid shape.
The material of the transparent core member is not particularly limited. However, if the material of the transparent core member is transparent glass, particularly optical glass, it is possible to easily select one having a high light transmittance and an appropriate light refractive index, whereby light incident from the light receiving surface can be selected. By adjusting the degree of approach in the axial direction of the transparent core member, in other words, by adjusting the degree of light absorption on the side surface of the transparent core member in the axial direction, for example, a plurality of different dyes arranged in the axial direction in a dye-sensitized solar cell It is possible to match the performance with the adsorbed porous semiconductor layer, or the light incident from the light receiving surface enters deep in the axial direction to efficiently use the entire side surface of the transparent core member as a substantial light receiving portion. Can be used. Examples of such optical glass include quartz glass, alkali glass, and borosilicate glass. Moreover, although not restricted to optical glass, the rigidity of a photoelectric conversion element can be improved by using glass for the material of a transparent core member. On the other hand, if the material of the transparent core member is a transparent resin, a flexible photoelectric conversion element can be obtained. Examples of such transparent resins include silicone resins and siloxane resins.

The transparent core member is composed of two or more transparent core member portions having different optical refractive indexes arranged in a direction orthogonal to the axis of the transparent core member, and the optical refractive index from the axial center side of the transparent core member. It is preferable that the transparent core member portion having a small refractive index and the transparent core member portion having a large optical refractive index are provided in this order. Thereby, the light incident from the light receiving surface can be made to enter deep in the axial direction, and a substantial light receiving portion can be formed in which the light amount is uniformly incident on the entire side surface of the transparent core member. For example, the optical refractive index of the transparent core member portion arranged on the axial center side can be about 1.46, and the optical refractive index of the transparent core member portion arranged on the side far from the axial center can be about 1.48. .
Further, the transparent core member has a translucent diffused surface (translucent property) that diffuses (scatters) a part of light toward the inside of the transparent core member on the side surface of the columnar or weight-shaped transparent core member. It is preferable that an irregular reflection surface is provided. Thereby, the light which injects from a light-receiving surface can be uniformly approached toward the photoelectric conversion cell structural member from the side surface of a transparent core member. Such a translucent irregular reflection surface may be provided by processing the side surface of the glass as a transparent core member into a ground glass shape, or a transparent material having a rough surface formed on one side. It may be provided on the outer periphery of the side surface.

  The transparent core member is preferably filled with a light scattering material that diffuses light incident from the light receiving surface toward the side surface of the core member. Thereby, the light which injects from a light-receiving surface can be efficiently guide | induced to a photoelectric conversion cell structural member via the side surface of a transparent core member.

  According to the basic configuration principle of the photoelectric conversion element according to the present embodiment described above, since the photoelectric conversion element is a fiber type or a tube type photoelectric conversion element, it is a conventional flat plate type, in other words, a flat panel type photoelectric conversion. Compared to an element, it is easy to produce cell constituent members such as electrode layers when the size is increased, and the electrical characteristics are also advantageous. Moreover, the area of the substantial light receiving part (side surface of the transparent core member) can be increased with respect to the actual light receiving surface (one end surface of the transparent core member). For this reason, the photoelectric conversion element suitable for the enlargement of an apparatus can be obtained with a simple manufacturing method. Further, in the case where the light receiving surface is positioned and used in parallel with the installation surface of the device using the photoelectric conversion element, it is possible to obtain a device in which the photoelectric conversion elements are integrated with high density on the installation surface. .

  Next, an embodiment will be described by taking a dye-sensitized solar cell as an example of the photoelectric conversion element.

  The dye-sensitized solar cell according to the first example of the present embodiment will be described with reference to FIGS. FIG. 1A shows a side cross-sectional view of a dye-sensitized solar cell as viewed from the longitudinal direction (axis side), and FIG. 1B shows the dye-sensitized solar cell from the left side of FIG. 1A. A front view is shown.

The dye-sensitized solar cell 10 according to the first example of the present embodiment includes a columnar transparent core member 12 and a dye-sensitized solar cell constituent member arranged in a stacked state on the side surface of the transparent core member 12. Consists of. The transparent core member may have a weight shape.
The transparent core member 12 is the same as that described in the basic configuration principle of the photoelectric conversion element according to the present embodiment, and a duplicate description is omitted, but the one end surface 12c is a light receiving surface on which light is incident. The other end surface 12 b is closed by, for example, a porous conductive metal layer 16. However, at this time, the other end surface 12b may be closed with an appropriate member such as resin. Further, although not shown, the side surface 12a of the transparent core member 12 is processed into a ground glass shape over the entire circumference, and transmits light toward the outside, and partly reflects light partially toward the inside of the transparent core member 12. It is a diffuse reflection surface. However, at this time, the irregular reflection surface may be an appropriate one such as a material in which one surface is formed as an irregular reflection surface and wound around the transparent core member 12.
The cell constituent member of the dye-sensitized solar cell 10 includes a porous semiconductor layer 14 containing a dye, a porous conductive metal layer 16, an electrolyte layer 18 and a catalyst layer on the side surface 12a of the transparent core member 12. The conductive layers 20 are arranged in this order. Reference numeral 21 denotes a casing that covers the cell member. The dye-sensitized solar cell 10 may further include an appropriate member such as a current collecting layer in addition to these cell members.

The porous semiconductor layer 14 containing a dye is a porous semiconductor layer to which a dye is adsorbed.
The dye has absorption at a wavelength in at least a part of the range of 400 nm to 1000 nm. Examples of such a dye include a metal complex having a COOH group such as a ruthenium dye and a phthalocyanine dye, and an organic dye such as a cyanine dye. N719 (manufactured by Solaronics) can be cited as a representative example of those having absorption on the low wavelength side, and a black die (manufactured by Solaronics) can be cited as a representative example of those having absorption on the high wavelength side.

For example, titanium, tin, zirconium, zinc, indium, tungsten, iron, nickel, silver, or other metal oxide can be used as the material of the porous semiconductor layer. Among these, titanium oxide (titania) can be used. Is more preferable.
The porous semiconductor layer is formed by baking a semiconductor material at a temperature of 300 ° C. or higher, more preferably 450 ° C. or higher. On the other hand, although there is no upper limit on the firing temperature, the temperature is sufficiently lower than the melting point of the material of the porous semiconductor layer, and more preferably 550 ° C. or lower. Further, when titanium oxide (titania) is used as the material of the porous semiconductor layer, it is preferably fired in a state of anatase crystals having high conductivity of titanium oxide at a temperature that does not shift to rutile crystals. Thereby, a porous semiconductor layer is formed.
The thickness of the porous semiconductor layer is not particularly limited, but is preferably 14 μm or more.

The porous conductive metal layer 16 uses a conductive metal sheet in which a porous film is formed from a conductive metal by sputtering or the like, or a large number of holes are formed in advance by machining, or in an embodiment described later. As described, it can be made porous by an appropriate method such as forming a hole in the laminated conductive metal layer.
The material of the porous conductive metal layer 16 may be, for example, a commonly used ITO (indium film doped with tin), FTO (tin oxide film doped with fluorine), or a SnO ₂ film. In addition, a metal mesh using an inexpensive metal, a metal layer in which an infinite number of holes are formed in advance, or a metal layer formed by thermal spraying or a thin film forming method can be used. On the other hand, from the viewpoint of increasing conductivity, a conductive film such as FTO may be formed on a glass material with a metal mesh, for example.

The electrolyte layer 18 contains iodine, lithium ions, ionic liquid, t-butylpyridine, and the like. For example, in the case of iodine, an oxidation-reduction body composed of a combination of iodide ions and iodine can be used. The redox form contains an appropriate solvent that can dissolve the redox form.
As the electrolytic solution layer 18, for example, a porous membrane having a porosity of about 70% by volume is impregnated with an electrolytic solution. At this time, in order to form the electrolyte layer 18 under the conductive layer 20 having the catalyst layer, the porous film is formed by an appropriate film forming method such as a coating method or a sputtering method, or an appropriate method in advance. After winding the porous film formed in (1) around the transparent core member 12, the porous film is impregnated with an electrolytic solution. The material of the porous membrane may be a resin, a metal, or an inorganic material other than these materials.
Further, instead of the porous membrane, a frame-like, for example, resin spacer is provided in the lower layer of the conductive layer 20 provided with the catalyst layer, and a catalyst layer formed in advance on the entire transparent core member 12 including the resin spacer portion is provided. After winding the sheet of the conductive layer 20, the electrolyte layer 18 may be formed by a method such as injecting an electrolyte into the space defined by the spacer.

  The conductive layer 20 including the catalyst layer is composed of, for example, a catalyst layer 20b formed of platinum and a conductive metal layer 20a formed of, for example, a titanium film, and the catalyst layer 20b faces the inner side where the transparent core member 12 is located. Be placed. At this time, the conductive metal layer 20a may be made of an inexpensive conductive metal.

According to the dye-sensitized solar cell 10 according to the first example of the present embodiment described above, the dye-sensitized solar cell can be manufactured at a low cost and is suitable for increasing the size of the apparatus. . Moreover, since there is no normally provided transparent conductive film or the like between the transparent core member 12 and the porous semiconductor layer 14 containing the dye, light can be efficiently introduced into the porous semiconductor layer 14 containing the dye. . In addition to these, there are other advantages described in the basic configuration principle of the photoelectric conversion element according to the present embodiment.
Here, a modification of the first example of the present embodiment will be described with reference to FIG.
The solar dye-sensitized battery cell 10 </ b> A according to the modification is the same as that of the dye-sensitized solar battery cell 10 except for the configuration of the transparent core member 12. For this reason, the overlapping description is omitted.
The transparent core member 12 is composed of two or more transparent core member portions 12 </ b> A and 12 </ b> B having different optical refractive indexes that are stacked and arranged in a direction orthogonal to the axis of the transparent core member 12. The transparent core member portion 12A is provided on the axial center side (inner side) of the transparent core member 12 and is formed of a material having a small light refractive index. The transparent core member portion 12B is provided outside the bright core member portion 12A and is formed of a material having a high light refractive index.
Thereby, the light incident from the light receiving surface can be made to enter deep in the axial direction, so that a substantial light receiving portion where the light amount is uniformly incident on the entire side surface of the transparent core member 12 can be formed. For example, the optical refractive index of the transparent core member portion 12A disposed on the axial center side is approximately 1.46, and the optical refractive index of the transparent core member portion 12B disposed on the side far from the axial center is approximately 1.48. Can do.

Next, a dye-sensitized solar cell according to the second example of the present embodiment will be described with reference to FIG. FIG. 2 shows a side sectional view of the dye-sensitized solar cell as seen from the longitudinal direction (axis side).
In addition, about the dye-sensitized solar cell structural member, the description which overlaps with the dye-sensitized solar cell 10 is abbreviate | omitted.

The dye-sensitized solar cell 10a according to the second example of the present embodiment includes two or more porous semiconductor portions in which the porous semiconductor layer 14 containing the dye is arranged in the axial direction of the transparent core member 12. (Here, an example composed of two porous semiconductor portions 14a and 14b is shown), and two or more porous semiconductor portions 14a and 14b are each adsorbed with different types of dyes. The other cell constituent members are the same as those of the dye-sensitized solar cell 10 according to the first example.
The type of dye adsorbed on the porous semiconductor portions 14a and 14b is not particularly limited. For example, N719 dye that absorbs a light component having a short wavelength is used in the porous semiconductor portion 14a on the light receiving surface side, and light enters. It is a preferable aspect to use, for example, a black dye that absorbs a light component having a long wavelength in the porous semiconductor portion 14b on the back side in the direction.
As a modification of the dye-sensitized solar cell 10a, a porous semiconductor layer containing a dye is composed of two or more porous semiconductor portions arranged in a direction orthogonal to the axis of the transparent core member. Or it is good also as a structure by which a different kind of pigment | dye is each adsorb | sucked to the porous semiconductor part more than that.
In this case, a dye that absorbs a short-wavelength light component is used in the porous semiconductor portion on the side close to the axis of the transparent core member, and a dye that absorbs a long-wavelength light component on the side far from the axis of the transparent core member. Use is a preferred embodiment. At this time, an electrolyte layer is provided on the outer side of the porous semiconductor part near the axis of the transparent core member and on the outer side of the porous semiconductor part far from the axis of the transparent core member, and the axis of the transparent core member Platinum carried on an appropriate porous member in contact with the electrolyte layer provided inside the porous semiconductor portion far from the center, that is, outside the porous semiconductor portion near the axis of the transparent core member If an iodine redox catalyst layer such as is provided, it can be used as two cells arranged in series. Further, when a porous conductor metal layer is provided instead of the porous member supporting the iodine redox catalyst layer, the porous conductor metal layer can be used as two cells arranged in parallel as an anode.

  According to the dye-sensitized solar cell 10a according to the second example of the present embodiment described above and the dye-sensitized solar cell of the modified example thereof, the dye-sensitized solar cell 10a according to the first example and Similar effects can be obtained. In particular, when the side surface 12a in the axial direction of the transparent core member 12 functions as a substantial light receiving portion, the transparent core member 12 is adsorbed to the porous semiconductor portion according to the light transmission state and light absorption state inside the transparent core member 12. By selecting the dye to be used, higher light utilization efficiency can be obtained.

Next, a dye-sensitized solar cell according to a third example of the present embodiment will be described with reference to FIG. FIG. 3 is a side sectional view of the dye-sensitized solar cell as seen from the longitudinal direction (axial direction).
In addition, about the dye-sensitized solar cell structural member, the description which overlaps with the dye-sensitized solar cell 10 is abbreviate | omitted.

  In the dye-sensitized solar cell 10b according to the third example of the present embodiment, a transparent conductive layer 17 made of, for example, an FTO layer is first provided on the outer periphery of the transparent core member 12, and then a porous containing a dye is provided. The conductive semiconductor layer 14 is provided, and the conductive layer 20 including the electrolytic solution layer 18 and the catalyst layer is arranged in this order. Note that the transparent conductive layer 17 is not limited to FTO, and an appropriate material such as ITO can be used.

  According to the dye-sensitized solar cell 10b according to the third example of the present embodiment, the same effect as that of the dye-sensitized solar cell 10 according to the first example can be obtained.

  Next, a dye-sensitized solar cell according to the fourth example of the present embodiment will be described with reference to FIG. FIG. 4 shows a side cross-sectional view of the dye-sensitized solar cell as viewed from the longitudinal direction (axis side).

The dye-sensitized solar cell according to the fourth example of the present embodiment includes two porous semiconductor parts 14c and 14d that are electrically insulated from each other in the dye-sensitized solar cell 10a of the second example. In addition to insulating, a porous conductive metal layer or a transparent conductive layer provided corresponding to this is insulated from each other to constitute two or more cells (independent cells, divided cells).
The dye-sensitized solar cell 10c according to the fourth example of the present embodiment shown in FIG. 4 is a porous semiconductor part on which different types of dyes are adsorbed in the dye-sensitized solar cell 10a of the second example. In addition to electrically insulating 14c and 14d, the porous conductive metal layer is also configured as two members that are electrically insulated from the conductive metal layer portions 16a and 16b. Except this point, the configuration is the same as that of the dye-sensitized solar cell 10a of the second example.
In place of the dye-sensitized solar cell 10c, in the dye-sensitized solar cell 10b according to the third example of the present embodiment, two porous semiconductor portions to which different types of dyes are adsorbed are provided. In addition, two cells may be configured as described above.

  According to the dye-sensitized solar cell 10c according to the fourth example of the present embodiment, the same effect as that of the dye-sensitized solar cell 10a of the second example can be obtained. Further, as shown in FIG. 4, a high current can be obtained by electrically connecting two cells in parallel, while a high voltage can be obtained by electrically connecting two cells in series. be able to.

  Next, a dye-sensitized solar cell according to a fifth example of the present embodiment will be described with reference to FIG. FIG. 9 shows a side sectional view of the dye-sensitized solar cell as seen from the longitudinal direction (axis side).

The dye-sensitized solar cell 10d according to the fifth example of the present embodiment shown in FIG. 9 has a basic configuration of the dye-sensitized solar according to the first example of the present embodiment shown in FIG. Similar to the battery cell 10. For this reason, the overlapping description is omitted.
The dye-sensitized solar cell 10 d is different from the dye-sensitized solar cell 10 in that the light scattering material 13 is filled in the transparent core member 12. In addition, the edge part on the opposite side to the light-receiving surface of the transparent core member 12 is obstruct | occluded by the stopper 12d formed, for example with a silicone rubber material.
The light scattering material 13 may be obtained by dispersing solid particles having surface reflectivity in an appropriate light transmissive medium, or may be an aggregate of light transmissive solid particles having surface reflectivity. .
The solid particles having surface reflectivity are not particularly limited, and for example, polystyrene beads, glass beads, ceramic powder and the like can be used. The particle size of the solid particles is not particularly limited, and can be, for example, about several hundred nm. The medium in which the solid particles are dispersed is not particularly limited, and for example, water, resin, glass or the like can be used. The dispersion concentration of the solid particles is not particularly limited, and can be, for example, about 0.1 vol%.
In addition, the irregular reflection surface formed on the side surface 12a in the dye-sensitized solar cell 10 according to the first example of the present embodiment may be used together or omitted in the dye-sensitized solar cell 10d. May be. In addition to the dye-sensitized solar cell 10 according to the first example of the present embodiment, the light scattering material 13 may be filled in the transparent core member 12 in other embodiments.

  According to the dye-sensitized solar cell 10d according to the fifth example of the present embodiment, the same effect as that of the dye-sensitized solar cell 10 of the first example can be obtained, and the light scattering material receives light. By irregularly reflecting the light incident from the surface toward the side surface of the core member, the light incident from the light receiving surface can be efficiently guided to the photoelectric conversion cell constituent member via the side surface of the transparent core member.

  The present invention will be further described with reference to examples. In addition, this invention is not limited to the Example demonstrated below.

Example 1
The solar cell manufacturing method of Example 1 will be described with reference to FIGS. In each of the following drawings, a side sectional view of the member as viewed from the longitudinal direction (axis side) is shown on the right side of the page, and a front view of the member as viewed from the left side in the longitudinal direction is shown at the left side of the page.
A cylindrical glass having a flat end surface 102c (indicated by D1 in FIG. 5A) of 8 mm and a length (indicated by L1 in FIG. 5A) of 30 mm is used as the core member 102. (See FIG. 5A).
The entire side surface 102a and the other end surface (bottom surface) 102b of the core member 102 were roughly polished with sandpaper to form a ground glass surface. After protecting one end surface 102c of the core member 102 with a protective member (adhesive tape not shown by Terraoka Co., Ltd.), the length of the side surface (indicated by L2 in FIG. 5B) is around the entire circumference of 20 mm. A titania paste (D paste manufactured by Solaronics) was applied and baked at 500 ° C. for 30 minutes to form a 10 μm-thick titania layer (porous semiconductor layer) 104 (see FIG. 5B).

Subsequently, after applying a mask having a thickness of 50 μm (indicated by reference symbol M in FIG. 5C, an adhesive tape manufactured by Terraoka Co., Ltd.) to the exposed portion of the core member 102 (portion where the titania layer 104 is not formed) On the surface of the titania layer 104, zinc oxide tetrapot crystal (trade name: Panatetra maximum size range: 2-20 μm: Matsushita Electric Works) was dispersed and applied by an electrospray method to form a coating layer 106 having a maximum thickness of 60 μm (FIG. 5 (C)).
Thereafter, the mask M is peeled off, a new mask M is applied to the one end face 102c of the core member 102, and a Ti film (Ti layer having a thickness of 300 nm is formed on the entire surface of the core member 102 including the surface of the titania layer 104 by sputtering. ) 108 was formed (see FIG. 5D).
Next, the coating layer 106 was dissolved and removed by rinsing with dilute hydrochloric acid to obtain a porous Ti layer 108 and the mask M was peeled off (see FIG. 5E).
Next, the core member 102 on which the porous Ti layer 108 is formed is immersed in a 0.05 wt% dye solution (N719, acetonitrile: tbutyl alcohol = 1: 1 manufactured by Solaronics) for 20 hours, and then the N719 dye is added to the titania layer 104. Adsorbed.

Next, a porous film (Advantech PTFE film, film thickness 10 μm) with a porosity of 71% by volume is wound with a length of 25 mm (L3 in FIG. 5 (F)) to cover the Ti layer 108 to form a porous film layer 110. Further, the Pt-sputtered Ti foil (Pt film 112b thickness 50 nm, Ti foil 112a thickness 100 μm) 112 is formed on one side so that both ends of the porous film layer 110 are exposed, and the Pt film 112b is the inner side. The length (L4 in FIG. 5F) was wound (see FIG. 5F). At this time, a Cu adhesive tape is pasted to form a lead electrode indicated by reference symbol A. In FIG. 5F and some of the following figures, the front view partially omits the display of members.
With the mask M (not shown) applied to the one end surface 102c of the core member 102, the right end portion of the porous film layer 110 is partially exposed to be coated with an epoxy resin, cured, and resin-sealed. Layer 114 was formed. Next, after removing the mask M on the left end face of the core member 102, an electrolytic solution composed of acetonitrile solution of iodine 40mM, LiI 500mM, t-Butylpyridine 580mM is exposed from the exposed portion of the porous film layer 110 (in FIG. 5G, Injection (in the direction of arrow X2) to impregnate the porous film layer 110. Finally, the exposed portion of the porous film layer 110 was closed with an epoxy resin 114, whereby the solar cell 100 of Example 1 was obtained (see FIGS. 5G and 5H).

  A solar simulator was used to irradiate AM1.5, 100 mW / cm 2 pseudo sunlight from the left end face (exposed end face) of the core member 102, and the characteristics of the produced solar cell were measured and evaluated. About the obtained photoelectric conversion efficiency, efficiency index 1.0 is displayed as a reference value for comparison with each following example.

(Example 2)
A cylindrical glass having a diameter (D1) equal to that of Example 1 and a length (L1) of 50 mm longer than that of Example 1 is used for the core member (102), and the titania layer (L2) is within a range of 40 mm ( 104), a 25 mm long (L3) porous film layer (110), and a 23 mm long (L4) Pt-sputtered Ti foil (112). The solar cell of Example 2 was produced under the conditions described above.
The efficiency index of the solar cell measured by the same method as in Example 1 was 1.2.

Example 3
As shown in FIG. 6, the titania layer (104) is divided into two regions (reference numerals 104a and 104b) every 10 mm in length (L2), the N719 dye is adsorbed to the titania layer 104a, and the titania layer 104b A solar cell of Example 3 was fabricated under the same conditions as in Example 1 except that black die (acetalonic acetonitrile: tbutyl alcohol = 1: 1 used) was adsorbed.
The solar cell efficiency index measured by the same method as in Example 1 was 1.3.

Example 4
As shown in FIG. 7, instead of the titania layer 104, an FTO layer 116 having a thickness of 200 nm is formed by a spray pyrolysis method using tin chloride and ammonium fluoride as raw materials. An electrode was formed, then a titania layer 104 was formed, and the porous film layer 110 was formed on the titania layer 104 without forming the coating layer (106) and the Ti layer (108). The solar cell 100a of Example 4 was produced under the conditions described above.
The efficiency index of the solar cell measured by the same method as in Example 1 was 0.8.

(Example 5)
As shown in FIG. 8, a cylindrical glass having a diameter (D1) equal to that in Example 1 and a length (L1) that is 60 mm longer than that in Example 1 is used as a core member (102). (104) is divided into two regions (reference numerals 104c and 104d) having a length (L2) of 20 mm, spaced by 10 mm, and the inner peripheral surface of the via hole is covered with an insulating film and then embedded with a conductive material. By the method, the titania layer and the porous Ti layer are electrically insulated from the two titania layers 104c and 104d and the two Ti layers 108a and 108b, respectively, by the insulating portion 118, and are electrically connected to the Ti layer 108a. The extraction electrode 120 covered with the insulating portion 118 is formed, the N719 dye is adsorbed on the titania layer 104c, and the black die (Solaronics Corporation) is adsorbed on the titania layer 104d. Acetonitrile: t-butyl alcohol = 1: 1 used) addition to adsorbed was prepared a solar cell of Example 5 under the same conditions as in Example 3.
As for the cell including the titania layer 104c, the cell including the titania layer 104c is electrically connected to the Pt-sputtered Ti foil 112 as the cathode electrode with the Ti layer 108b as the anode as shown in FIG. Two cells were connected in series by electrically connecting the Ti layer 108b to the anode electrode and the lead electrode 120 to the Pt-sputtered Ti foil 112 (see FIG. 4).

The efficiency index of the solar cell measured by the same method as in Example 1 was 1.4.

(Example 6)

A solar cell was fabricated in the same manner as in Example 1 except that one end face was flat and the other end face was a cylindrical (copper) glass having a hollow diameter of 8 mm and a length of 30 mm as a core member. A dispersion of polystyrene beads as a scattering material dispersed in water was filled in the core member, and a plug made of silicone rubber was plugged on the other end surface (see FIG. 9). A dispersion in which polystyrene beads were dispersed in water was prepared by diluting a 258 nm polystyrene 10 vol% dispersion (Uniform Microparticles manufactured by Seradyn) 200 times with water. The efficiency index of the solar cell measured by the same method as in Example 1 was 1.25.

10, 10A, 10a, 10b, 10c, 10d, 100, 100a Dye-sensitized solar cell 12 Transparent core member 12A, 12B Transparent core member portion 12a, 102a Side surface 12b, 102b Other end surface 12c, 102c One end surface 12d Plug 13 Light Scattering material 14 Porous semiconductor layer 14a, 14b, 14c, 14d containing a pigment Porous semiconductor part 16 Porous conductive metal layer 16a, 16b Conductive metal layer part 17 Transparent conductive layer 18 Electrolyte layer 20 Provided with catalyst layer Conductive layer 21 housing 102 core member 104, 104a, 104b, 104c, 104d titania layer 106 coating layer 108 Ti film 110 porous film layer 112 Ti foil sputtered Pt on one side 112a Ti foil 112b Pt film 114 epoxy resin 116 FTO layer 118 Ti layer 120 Lead electrode

Claims (6)

One end surface of the columnar transparent core member or the bottom surface of the weight-shaped transparent core member is a light receiving surface, and on the side surface of the transparent core member, a porous semiconductor layer containing a dye, a porous conductive metal layer, an electrolyte solution A photoelectric conversion element, which is a dye-sensitized solar cell in which a conductive layer including a layer and a catalyst layer is arranged in this order. The transparent core member having a columnar shape or a weight-like shape is composed of two or more transparent core member portions having different optical refractive indexes arranged in a direction perpendicular to the axis of the transparent core member. 2. The photoelectric conversion element according to claim 1, wherein a transparent core member portion having a small light refractive index and a transparent core member portion having a large light refractive index are provided in this order from the axial center side . 2. The photoelectric conversion element according to claim 1, wherein a light-transmitting irregular reflection rough surface for irregularly reflecting toward the inside of the transparent core member is provided on a side surface of the columnar or weight-shaped transparent core member. . The photoelectric conversion element according to claim 1, wherein a light scattering material is filled in the columnar or weight-shaped transparent core member . The porous semiconductor layer containing the dye is composed of two or more porous semiconductor portions arranged in the axial direction of the transparent core member or in a direction perpendicular to the axial line, and the two or more porous semiconductor portions The photoelectric conversion element according to claim 1, wherein different types of dyes are adsorbed on the photoelectric conversion element . The two or more porous semiconductor portions and the porous conductive metal layer or the transparent conductive layer provided corresponding to the two or more porous semiconductor portions are insulated from each other, and are formed into two or more cells. The photoelectric conversion element according to claim 5 .

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