JP2011204464A5 - - Google Patents

Description

In order to achieve the above object, one aspect of the dye-sensitized solar cell of the present invention includes a first substrate, a second substrate disposed opposite to the first substrate, and a first substrate of the first substrate . A first electrode formed on the first surface, the first surface facing the second surface of the second substrate, and the first electrode disposed on the first electrode An electron collection -dye layer , a catalyst layer disposed on the second surface and facing the first substrate as a diffuse reflection surface, the electron collection-dye layer, and the catalyst And an electron supply agent disposed between the layers .
In order to achieve the above object, one embodiment of the dye-sensitized solar cell of the present invention includes a first electrode, a second electrode facing the first electrode, and a first electrode of the first electrode. An electron collecting-dye layer disposed on a surface, the first surface is opposite to a second surface of the second electrode, and is disposed on the second surface; It is characterized by comprising: a catalyst layer whose opposing surface is formed as a diffuse reflection surface; and an electron supply agent disposed between the electron collection-dye layer and the catalyst layer.

Here, in the present embodiment, in order to increase the power generation efficiency by reusing the light incident on the dye-sensitized solar cell from the transparent substrate 10 side and transmitted through the electron collection-dye layer 30 by diffuse reflection, The surface of the catalyst layer 60 is a diffuse reflection surface. Therefore, fine irregularities are formed on the counter substrate 40. The irregularities may, for example to solution may form Rikatachi by the etching chemical method by, for example, it may be formed by sandblasting or the like physical means. A diffuse reflection surface is formed by forming the conductive film 50 and the catalyst layer 60 made of platinum on the counter substrate 40 on which fine irregularities are formed.

The transparent substrate 10 and the counter substrate 40, an electron collecting the transparent substrate 10 - to a plane dye layer 30 is formed, the surface catalyst layer 60 of the counter substrate 40 are formed, but opposite, respectively, opposite For example, the peripheral surfaces of the opposing surfaces are bonded together by the sealing material 70 so as to have a gap of about 10 to 50 μm between the surfaces to be processed. An electron supply agent 80 that is an electrolyte is sealed in the gap.

The electrons of the dye in the electron collecting-dye layer 30 excited here are transferred to the electron collecting agent in the electron collecting-dye layer 30 composed of, for example, titanium oxide which is a wide gap semiconductor. That is, the dye is oxidized. The electrons received by the electron scavenger move to the transparent conductive film 20. On the other hand, the dye that has lost electrons is supplied with electrons from, for example, I ⁻ of the electron supply agent 80 in contact with the conductive film 50 having the catalyst layer 60. That is, the dye is reduced by the electron supply agent 80. 3I ⁻ becomes I ₃ ⁻ when electrons are supplied to the dye. Therefore, for example, I ₃ ⁻ of the electron supply agent 80 tries to receive electrons from the conductive film 50. At this time, a potential difference is generated between the transparent conductive film 20 and the conductive film 50. If an external circuit is connected between the transparent conductive film 20 and the conductive film 50, the electrons that have moved to the transparent conductive film 20 move to the conductive film 50 through the external circuit. Then, the electrons move to, for example, I ₃ ⁻ of the electron supply agent 80, and I ₃ ⁻ becomes 3I ⁻ . The dye that has lost electrons is supplied with electrons from, for example, I ⁻ of the electron supply agent 80. In this way, by connecting an external circuit between the transparent conductive film 20 and the conductive film 50, the external circuit can extract current from the dye-sensitized solar cell according to the present embodiment that has absorbed light. . That is, this dye-sensitized solar cell functions as a battery.

Unevenness was formed on the counter substrate 40 by chemical polishing. FIG. 3 shows the surface shape of the counter substrate 40 on which the irregularities are formed. 3A shows a plan view, and FIG. 3B shows a perspective view. The uneven surface had a center line average roughness Ra of 0.137 μm and a ten-point average height Rz of 0.692 μm. Here, the centerline average roughness Ra is a length of interest, and the roughness curve is folded back from the centerline, and the area of the portion surrounded by the roughness curve and the centerline is the length of interest. Represents the divided value. Further, the ten-point average height Rz is a difference value between the average value of the heights of the five peaks from the highest and the average value of the depths of the five valleys from the lowest in the reference length of the cross-sectional curve. To express. Ra is preferably 0.14 μm ± 0.1 μm and Rz is preferably 0.7 μm ± 0.3 μm.

The reason why the conversion efficiency η of this embodiment is higher than that of the comparative example can be considered as follows. Light that enters from the transparent substrate 10 side and reaches the catalyst layer 60 without being absorbed by the dye in the electron collection-dye layer 30 is reflected by the surface of the catalyst layer 60 and enters the electron collection-dye layer 30 again. To do. At this time, in the case of the comparative example, since the surface of the catalyst layer 60 is a mirror surface, the reflected light travels straight and the optical path passing through the electron collection-dye layer 30 is short. For this reason, a part of the light is absorbed by the pigment, but a lot of other light is transmitted without being absorbed. In contrast, in the case of the present embodiment, the surface of the catalyst layer 60 is a diffuse reflection surface, so that the light path that is diffusely reflected and passes through the electron collection-dye layer 30 becomes long. Therefore, it is considered that the proportion of light that will be absorbed into the dye than in the comparative example increases. For this reason, it is considered that the conversion efficiency η has increased.

As described above, in the dye-sensitized solar cell according to the present embodiment, since the surface of the catalyst layer 60 is a diffuse reflection surface, the ratio of the reflected light absorbed by the dye is that the surface of the catalyst layer 60 is specular. Higher than the case. For this reason, the conversion efficiency η increases. That is, according to this embodiment, the performance of the dye-sensitized solar cell is improved.

[Modification]
In order to improve the performance of the dye-sensitized solar cell, it is also meaningful to devise the configuration of the electron collection-dye layer 30. That is, as shown in FIG. 6, two types of titanium oxides having different particle diameters may be used for the anatase type titanium oxide constituting the electron scavenger 32. For example, the electron collection agent 32 having a large particle size is called an electron transfer electron collection particle (second electron collection particle) 34, and the electron collection agent 32 having a small particle size is used for dye adsorption electron collection. This is referred to as particle (first electron collection particle) 36.

Next, examples of the dye-sensitized solar cell of this modification will be described. Here, the dye-sensitized solar cell of this example using titanium oxide as two types of electron-trapping agents 32 having different diameters as the electron-collecting particles 34 for electron transfer and the electron-trapping particles 36 for dye adsorption was compared with the dye-sensitized solar cell of Comparative example having a diameter titanium oxide was used as one type of electronic scavenger 32, performance of. What is compared is the value of the fill factor (FF), which is the ratio of the actual power to the apparent maximum power.

As a result of measuring three times for each of the present example and the conventional example, the FF value is 44.4 ± 1.3 (average ± standard deviation) in the dye-sensitized solar cell according to the present example. In the dye-sensitized solar cell, it was 25.6 ± 0.3 (average ± standard deviation). That is, the FF value of this example increased by 74% compared to the conventional example.

Possible reasons for this difference are as follows. As shown in the schematic diagram of the electron collecting-dye layer 30 of the conventional example in FIG. 7A, in the conventional example, as indicated by the white arrowhead A in FIG. ⁻ Is transmitted to the transparent conductive film 20 through many particles having a small diameter constituting the electron scavenger 32. Thus electrons e ^- are required many Eru Yue the joint portion of the particles in the electron scavenger 32. For this reason, the resistance of the electrical connection path formed in the electron scavenger 32 becomes high and electrons are not easily transmitted. Further, as indicated by the white arrowhead B in FIG. 7A, the dyes 38 are associated with each other and enter between the particles constituting the electron scavenger 32, so that the particles constituting the electron scavenger 32 are in contact with each other. There may be a part that does not touch. And in the part which the particles which comprise the electron scavenger 32 do not contact in this way, an electron e < ^- > will not be transmitted.

On the other hand, as shown in the schematic diagram of the electron collection-dye layer 30 of this example in FIG. 7B, in this example, the electrons e ⁻ emitted from the dye 38 have a small number of large diameters. It is transmitted to the transparent conductive film 20 through the electron collecting particles 34 for electron transmission. Therefore, there are few junction parts of the electron collection particle | grains 34 for electron transmission which the electron e < ^- > needs to exceed. In addition, since the electron-collecting particles 34 for electron transfer have a large diameter and a large surface area per one, the bonding between the electron-collecting particles 34 for electron transfer is excellent. For this reason, the resistance of the electrical connection path formed in the electron scavenger 32 is lower than in the case of FIG. 7B, and electrons are easily transmitted. Further, since there are many dye-adsorbing electron-collecting particles 36, the surface area is large, and the roughness factor is 1000 or more, which is more than the value that is said to be necessary in a dye-sensitized solar cell. For this reason, a sufficient number of dyes 38 are adsorbed by the electron scavenger 32.

DESCRIPTION OF SYMBOLS 10 ... Transparent substrate (1st board | substrate) , 20 ... Transparent electrically conductive film (1st electrode) , 30 ... Electron collection-dye layer, 32 ... Electron collection agent, 34 ... Electron collection particle | grains for electron transmission (1st 2 electronic trapping particles), 36 ... dye adsorption for electronic trapping particles (first electronic trapping particles), 38 ... dye, 40 ... counter substrate (second substrate), 50 ... conductive film (second Electrode) , 55 ... platinum underlayer, 60 ... catalyst layer, 70 ... sealing material, 80 ... electron supply agent.

Claims (11)

A first substrate;
A second substrate disposed opposite the first substrate;
A first electrode formed on a first surface of the first substrate , wherein the first surface is opposite to a second surface of the second substrate ;
An electron collection -dye layer disposed on the first electrode;
A catalyst layer disposed on the second surface and facing the first substrate as a diffuse reflection surface;
An electron supply agent disposed between the electron collection-dye layer and the catalyst layer;
Comprising
A dye-sensitized solar cell characterized by the above. The second surface includes a rough surface,
The diffuse reflection surface is formed such that the shape of the diffuse reflection surface follows the shape of the rough surface,
The dye-sensitized solar cell according to claim 1 . The rough surface is a frosted surface , a chemically etched surface and / or a sandblasted surface,
The dye-sensitized solar cell according to claim 2 . Further comprising an underlayer disposed between the second substrate and the catalyst layer and formed to increase the surface area of the catalyst layer while being in contact with the catalyst layer;
The dye-sensitized solar cell according to any one of claims 1 to 3 . The catalyst layer comprises platinum;
The underlayer includes titanium;
The dye-sensitized solar cell according to claim 4 . The electron collecting-dye layer includes an electron collecting agent including titanium oxide.
The dye-sensitized solar cell according to any one of claims 1 to 5, wherein: The dye is
Has an excited state and a ground state,
The dye in the excited state has a higher energy level than the electron scavenger,
The dye in the ground state has a lower energy level than the electron donor;
A dye-sensitized solar cell according to any one of claims 1 to 6 . A first electrode;
A second electrode facing the first electrode;
An electron collection-dye layer disposed on the first surface of the first electrode;
The catalyst layer in which the first surface faces the second surface of the second electrode, is disposed on the second surface, and the surface facing the first electrode is formed as a diffuse reflection surface When,
An electron supply agent disposed between the electron collection-dye layer and the catalyst layer;
Comprising
A dye-sensitized solar cell characterized by the above. The electron collecting-dye layer comprises an electron collecting agent and a dye to form a single layer,
The electron collecting agent includes a mixture of first electron collecting particles having a particle size within a first particle size range and second electron collecting particles having a particle size within a second particle size range. The minimum value of the second particle size range is greater than the maximum value of the first particle size range,
The dye-sensitized solar cell according to claim 8 . The first electron collection particles are configured to adsorb the dye,
The second electron collection particles are configured to transmit electrons emitted from the dye to the first electrode.
The dye-sensitized solar cell according to claim 9 . The average diameter of the second electron collection particles is 10 times or more the average diameter of the first electron collection particles.
The dye-sensitized solar cell according to claim 9 .