JP2013004238A - Optical response element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical response element with an excellent durability and optical responsiveness.SOLUTION: An optical response element is configured by laminating a transparent substrate, a conductive film, a short circuit prevention layer, a semiconductor layer and a counter electrode in this order. The semiconductor layer has: an n-type semiconductor part having porous bodies arranged and provided on a surface of the short circuit prevention layer and dye attached to a surface of the porous bodies; and a p-type semiconductor part arranged and provided between the n-type semiconductor part and the counter electrode. The porous body of the n-type semiconductor part is formed of titanium oxide or zinc oxide. The p-type semiconductor part is formed of metal oxide. A bandgap of the metal oxide forming the p-type semiconductor part is preferably 3 eV or more and 4 eV or less.

Description

  The present invention relates to a photoresponsive element that converts light into electricity.

As one of the photoresponsive elements, there is a dye-sensitized solar cell using a dye and porous TiO ₂ . The operation mechanism of this dye-sensitized solar cell is as follows. That is, the dye that absorbs light is excited, the electrons move to the TiO ₂ side by the transition, and the dye receives electrons from the electrolyte containing iodine and is regenerated (returns to the ground state). Electrons are exchanged by this mechanism and generate electricity (light response). In addition to the above, there are electrolytes using CuI and CuSCN, and electrolytes that are gelled into a solid state (see JP 2001-167808 A).

  As described above, in a dye-sensitized solar cell (cell) using an electrolytic solution, the electrolytic solution in the cell leaks due to a temperature change, so that a problem remains in durability. In order to prevent leakage of the electrolytic solution, strict sealing is required, and the manufacturing process becomes complicated, resulting in an increase in manufacturing cost. Further, since CuI and CuSCN are deteriorated by light, it is difficult to produce a stable dye-sensitized solar cell. Furthermore, when the electrolyte solution is gelated in a dye-sensitized solar cell, the degree of freedom of iodine in the electrolyte solution decreases, so the regeneration efficiency of the dye may decrease and the photoresponsiveness may decrease. . Therefore, development of a photoresponsive element excellent in durability and photoresponsiveness is desired.

JP 2001-167808 A

  The present invention has been made based on the above-described circumstances, and an object thereof is to provide a photoresponsive element that is excellent in durability and photoresponsiveness.

The invention made to solve the above problems is
A transparent substrate, a conductive film, a short-circuit prevention layer, a semiconductor layer and a counter electrode are laminated in this order,
The semiconductor layer is
A porous body disposed on the surface of the short-circuit prevention layer, and an n-type semiconductor portion having a dye attached to the surface of the porous body;
A p-type semiconductor portion disposed between the n-type semiconductor portion and the counter electrode,
The porous body of the n-type semiconductor part is formed from titanium oxide or zinc oxide,
The p-type semiconductor portion is formed of a metal oxide.

  According to the photoresponsive element, since a p-type semiconductor portion formed of a metal oxide is used instead of the electrolytic solution, the photoresponsive element is excellent in durability and can exhibit excellent photoresponsiveness.

  It is preferable that the band gap of the metal oxide forming the p-type semiconductor portion is 3 eV or more and 4 eV or less. Thus, by using a semiconductor having a wide gap in the above range as the p-type semiconductor part, excited dye electrons easily flow only to the n-type semiconductor part side, and further enhances the photoresponsiveness of the photoresponsive element. be able to.

  The p-type semiconductor part is formed of nickel oxide or bismuth oxide, the nickel oxide contains 0.8 atom or more and 1.2 atom or less of oxygen with respect to 1 atom of nickel, and the bismuth oxide includes: It is preferable that oxygen is contained in an amount of 1.3 to 1.7 atoms with respect to 1 atom of bismuth. Nickel oxide or bismuth oxide having such a composition has a preferable band gap, and can further improve the photoresponsiveness of the photoresponsive element.

  The p-type semiconductor part is preferably formed by sputtering. By forming the p-type semiconductor portion by sputtering in this way, the dye adhesion state in the n-type semiconductor portion can be maintained during the formation, and the durability and photoresponsiveness of the photoresponsive element can be further increased. Can be increased.

  The p-type semiconductor part is preferably non-porous. As described above, the p-type semiconductor portion is non-porous, that is, has a dense shape, so that a short circuit between the n-type semiconductor portion and the counter electrode can be suppressed, and photoresponsiveness can be further improved. it can.

  The p-type semiconductor part can be formed in layers. Thus, by making a p-type semiconductor part into a layer form, the short circuit between an n-type semiconductor part and a counter electrode can be suppressed, and photoresponsiveness can be improved more.

  The n-type semiconductor portion is preferably porous with an average pore diameter of 10 nm or more and 50 nm or less. Thus, by making the n-type semiconductor part into a porous shape having pores in the above range, the surface area of the n-type semiconductor part and the contact area between the n-type semiconductor part and the p-type semiconductor part are increased, and photoresponsiveness is increased. Etc. can be further enhanced.

  For forming the porous body of the n-type semiconductor part, it is preferable to use particles having an average particle diameter of 50 nm or more and 100 nm or less made of titanium oxide or zinc oxide. Thus, by forming the porous body of the n-type semiconductor portion from the particles having the above size, a preferable porous shape can be obtained, and more excellent durability and photoresponsiveness can be exhibited.

  The titanium oxide contains 1.8 to 2.2 atoms of oxygen with respect to 1 atom of titanium, and the zinc oxide has oxygen of 0.8 to 1.2 atoms with respect to 1 atom of zinc. It is good to contain atoms or less. By using titanium oxide or zinc oxide having such a composition, the band gap becomes a suitable range, and the photoresponsiveness can be further improved.

  It is preferable that the n-type semiconductor portion is formed in layers, and the film thickness of the n-type semiconductor portion is 2 μm or more and 10 μm or less. Thus, by making the n-type semiconductor portion into a layer shape having a film thickness in the above range, the optical response can be further improved.

  As described above, the photoresponsive element of the present invention is excellent in durability and photoresponsiveness. Therefore, the photoresponsive element can be suitably used as an optical sensor, a solar cell, or the like.

Schematic sectional view showing a photoresponsive element according to an embodiment of the present invention. FIG. 1 is a schematic cross-sectional view showing a photoresponsive element according to an embodiment different from FIG. SEM photograph of semiconductor layer in photoresponsive element of Example 1 The graph which shows the relationship between the film thickness of the n-type semiconductor part in an Example, and light absorption rate

  Hereinafter, embodiments of the photoresponsive element of the present invention will be described in detail with reference to the drawings as appropriate.

  1 includes a transparent substrate 1, a conductive film 2, a short-circuit prevention layer 3, a semiconductor layer 4, and a counter electrode 5 stacked in this order. The semiconductor layer 4 includes an n-type semiconductor portion 6 and a p-type semiconductor portion 7 formed from a metal oxide.

  The photoresponsive element 10 includes a p-type semiconductor portion 7 formed of a metal oxide instead of the electrolyte solution of a conventional dye-sensitized solar cell. Therefore, the photoresponsive element 10 has no durability such as liquid leakage and has excellent durability. Moreover, the said photoresponsive element 10 can exhibit the outstanding photoresponsiveness by having the said structure.

  The transparent substrate 1 is formed from a transparent material. As a material of the transparent substrate 1, for example, glass such as alkali silicate glass, non-alkali glass and quartz glass, synthetic resin such as acrylic resin and PET, and the like can be used. Among these, glass is preferable from the viewpoints of strength and thermal stability. The glass is preferably chemically or thermally strengthened.

  Although it does not specifically limit as thickness of the transparent substrate 1, Usually, it is about 0.1 mm or more and 10 mm or less. The transparent substrate 1 may be, for example, a flexible substrate made of synthetic resin and having a reduced thickness.

The conductive film 2 is laminated on the surface of the transparent substrate 1. The conductive film 2 is formed from a conductive transparent material. Examples of the material of the conductive film 2 include FTO, ITO, SnO: F (FTO), In ₂ O ₃ : Sn (ITO), SnO ₂ : Sb, SnO ₂ : F, ZnO: Al, ZnO: F, and CdSnO _4. And the like. Among these, materials containing FTO and ITO are particularly preferable from the viewpoints of conductivity and transparency.

  The thickness of the conductive film 2 is not particularly limited and can be, for example, 100 nm or more and 10 μm or less.

  The short-circuit prevention layer 3 is laminated on the surface of the conductive film 2. This short-circuit prevention layer 3 prevents a fine short circuit between the conductive film 2 and the p-type semiconductor part 7. That is, a short circuit due to at least a part of the p-type semiconductor portion 7 reaching the conductive film 2 is prevented. In addition, when this short circuit arises, photoresponsiveness will fall.

The short-circuit prevention layer 3 is preferably non-porous, that is, a dense film having substantially no voids. Examples of the material for forming the short-circuit prevention layer 3 include titanium oxide (for example, TiO ₂ ) and zinc oxide. Moreover, it does not specifically limit as thickness of a short circuit prevention layer, For example, they are 10 nm or more and 1 micrometer or less.

  The method for laminating the short-circuit prevention layer 3 is not particularly limited, and a known method such as a sputtering method, a spray method, a spin coating method, a chemical bath deposition method, or the like can be used.

  The n-type semiconductor unit 6 is disposed in a layered manner on the surface of the short-circuit prevention layer 3. The n-type semiconductor unit 6 includes a semiconductor exhibiting n-type properties (majority carriers are free electrons). The n-type semiconductor unit 6 includes a porous body 8 (n-type semiconductor) disposed on the surface of the short-circuit prevention layer 3 and a dye 9 attached to the surface of the porous body 8.

  The n-type semiconductor part 6 is porous. The average pore diameter of the n-type semiconductor portion 6 is preferably 10 nm or more and 50 nm or less, and more preferably 20 nm or more and 40 nm or less. According to the photoresponsive element 10, the n-type semiconductor portion 6 is formed into a porous shape having a void in the above range, so that the surface area of the n-type semiconductor portion 6 and the n-type semiconductor portion 6 and the p-type semiconductor portion 7 can be reduced. The contact area is enlarged, and the photoresponsiveness and the like can be further improved.

  When the average pore diameter of the n-type semiconductor portion 6 is less than the above lower limit, the surface area becomes small, so that sufficient photoresponsiveness may not be exhibited. On the contrary, when the average pore diameter exceeds the upper limit, the strength of the n-type semiconductor portion 6 may be reduced.

  In addition, this average pore diameter (average pore diameter) is a value measured by a mercury intrusion method described in JIS-K1150.

  Although it does not specifically limit as a film thickness (average film thickness) of the n-type semiconductor part 6, 2 micrometers or more and 10 micrometers or less are preferable, and 4 micrometers or more and 8 micrometers or less are more preferable. By setting the film thickness of the n-type semiconductor portion 6 within the above range, the photoresponsiveness can be further improved. When this film thickness is less than the above lower limit, the surface area sufficient to sufficiently adsorb the dye 9 is insufficient, the light absorption efficiency is lowered, and sufficient photoresponsiveness may not be exhibited. On the contrary, when this film thickness exceeds the upper limit, the light absorption rate reaches a peak, while the series resistance increases, so that the photoresponsiveness may decrease.

The porous body 8 is porous and is formed from titanium oxide or zinc oxide. The titanium oxide preferably contains 1.8 atoms or more and 2.2 atoms or less of oxygen (oxygen atoms) with respect to 1 atom of titanium. Examples of the titanium oxide having the above composition include TiO ₂ . Moreover, it is preferable that the said zinc oxide contains 0.8 atom or more and 1.2 atom or less of oxygen (oxygen atom) with respect to 1 atom of zinc. Examples of the zinc oxide having the above composition include ZnO. According to the photoresponsive element 10, by using the titanium oxide or zinc oxide having the above composition in the porous body 8 of the n-type semiconductor portion 6, the band gap becomes a suitable range, and the photoresponsiveness is further improved. Can be increased.

  In view of the fact that it has a band gap in an appropriate range and can further improve the photoresponsiveness, and the economic efficiency, it is preferable to use titanium oxide as the porous body 8.

  The method for forming the porous body 8 is not particularly limited, and a known method can be used. A paste of particles made of titanium oxide or zinc oxide is applied to the surface of the short-circuit prevention layer 3 and sintered. It is preferable to make it. As the coating method, for example, a screen printing method or the like can be used.

  By using particles made of titanium oxide or zinc oxide to form the porous body 8, the porous porous body 8 (n-type semiconductor portion 6) can be easily formed. The average particle size of these particles is preferably 50 nm or more and 100 nm or less, and more preferably 60 nm or more and 90 nm or less. By setting the average particle size of the particles in the above range, the porous body 8 and, as a result, the n-type semiconductor portion 6 can be made into a preferable porous shape, and more excellent durability and photoresponsiveness are exhibited. be able to.

In addition, this average particle diameter uses the half width of the diffraction peak obtained from the X-ray diffraction measurement, and the following Serrer equation:
d = 0.9λ / (Bcos θ)
(D: average particle diameter, λ: X-ray wavelength, B: half width of diffraction peak, θ: diffraction angle)
It is a value calculated from

  In addition, by using particles having a particle size of 50 nm or more and 100 nm or less as the particles made of titanium oxide or zinc oxide, the sintering temperature can be lowered to about 500 ° C. By sintering at such a temperature, a glass substrate, a synthetic resin substrate, or the like can be used as the transparent substrate 1, and as a result, the selectivity of the material can be increased and the manufacturing cost can be reduced.

  As the dye 9, a known dye used for a dye-sensitized solar cell can be used. Examples of the dye 9 include metal complex dyes such as Ru metal complex, Os metal complex, and Cu metal complex, and organic dyes such as methine dye and phthalocyanine dye. Among these, a metal complex dye is preferable and a Ru metal complex is more preferable because the photoresponsive element 10 can exhibit high photoresponsiveness and the like.

The dye 9 has a COOH group, an OH group, a SO ₃ H group, an NCS group, and —P (O) (OH) _{2 in} view of the adsorptivity to the surface of the porous body 8 (titanium oxide or zinc oxide). It preferably has a polar group such as a group, -OP (O) (OH) ₂ group. Among these groups, it is more preferable to have a COOH group or an NCS group. These groups may form a salt with an alkali metal or the like, or may form a salt in the molecule.

  Further, the maximum absorption wavelength of the dye 9 is preferably 450 nm or more and 650 nm or less, and more preferably 500 nm or more and 600 nm or less. By using the dye 9 having the maximum absorption wavelength in this range, the photoresponsiveness of the photoresponsive element can be further increased.

  As a commercially available product of a preferable Ru metal complex as the dye 9, Ruthenizer 535-bisTBA (cis-diisothiocyanato-bis (2,2'-bipyridineyl-4,4'-dicarboxylato) ruthenium (et) bisbutiumuum (et) buraniumium (et)) ), Ruthenizer 535, Ruthenizer 620-1H3TBA, Ruthenizer 520-DN, and the like.

  The dye 9 can be attached by immersing the porous body 8 (sintered titanium oxide or the like) in a solution containing the dye 9 and then drying it.

  The p-type semiconductor part 7 is arranged in layers on the surface of the n-type semiconductor part 6. The p-type semiconductor portion 7 is a semiconductor having p-type properties (majority carriers are holes).

  The metal oxide (p-type semiconductor) forming the p-type semiconductor portion 7 is not particularly limited as long as it functions as a p-type semiconductor. Copper oxide, palladium oxide, chromium oxide, molybdenum oxide , Nickel oxide, bismuth oxide, and the like. Among these metal oxides, those having a band gap of 3 eV or more and 4 eV or less are preferred, those having a band gap of 3.5 eV or more are more preferred, and those having a band gap of 3.7 eV or more are more preferred. By using a semiconductor having a wide gap in the above range as the p-type semiconductor portion 7, the excited electrons of the dye 9 can easily flow only to the n-type semiconductor portion 6 side, thereby further improving the photoresponsiveness of the photoresponsive element. be able to. When this band gap is less than 3 eV, reverse electron transfer from the dye 9 to the p-type semiconductor portion 7 may occur, and the photoresponsiveness may decrease. Conversely, even when the band gap exceeds 4 eV, performance such as photoresponsiveness may deteriorate. In addition, as the n-type semiconductor portion 6, a titanium oxide or the like (band gap 3 to 4 eV) to which a dye having a band gap of 1.4 to 1.7 eV (for example, a Ru metal complex) is attached is used. When the p-type semiconductor part 7 having a gap is used, the above effect becomes more remarkable.

Specific examples of the metal oxide having such a preferable band gap include nickel oxide (NiO and the like) and bismuth oxide (Bi ₂ O _{3 and the} like), and nickel oxide is more preferable. .

The nickel oxide preferably contains 0.8 atom or more and 1.2 atom or less of oxygen (oxygen atom) with respect to 1 atom of nickel. An example of such nickel oxide is NiO. Moreover, it is preferable that the said bismuth oxide contains 1.3 atoms or more and 1.7 atoms or less of oxygen (oxygen atom) with respect to 1 atom of bismuth. Examples of such bismuth oxide include Bi ₂ O ₃ . Nickel oxide or bismuth oxide having the above composition has a preferable band gap in the above range, and can further improve the photoresponsiveness of the photoresponsive element 10.

  The p-type semiconductor part 7 is preferably non-porous. According to the photoresponsive element 10, the p-type semiconductor portion 7 is made of a non-porous shape, that is, a dense shape, so that a short circuit between the n-type semiconductor portion 6 and the counter electrode 5 can be suppressed. Photoresponsiveness can be further increased.

  Although it does not specifically limit as a film thickness (average film thickness) of the said p-type semiconductor part 7, For example, 10 nm or more and 1 micrometer or less are preferable, and 30 nm or more and 300 nm or less are more preferable. When the film thickness of the p-type semiconductor portion 7 is less than the lower limit, a hole is formed in the film, and a short circuit may occur. On the contrary, when the film thickness of this p-type semiconductor part 7 exceeds the said upper limit, there exists a possibility that series resistance may become high and photoresponsiveness may fall.

  A method for forming the p-type semiconductor portion 7 (a method for laminating on the surface of the n-type semiconductor portion 6) is not particularly limited. For example, a metal film is formed by sputtering, chemical bath deposition, electrolytic deposition, or plating. In addition, a method of oxidizing or sulfurating the metal film can be used.

  Among these, the sputtering method is preferable. Bonding between the porous body 8 and the dye 9 in the n-type semiconductor portion 6 is stable under neutral conditions. In addition, this bond is weak to heat and easily decomposed. However, when the sputtering method is used, since there is no pH change or heating, the p-type semiconductor portion 7 can be formed while maintaining the state in which the dye 9 is adsorbed. As this sputtering method, reactive sputtering with oxygen using a metal target or sputtering using a metal oxide target can be performed.

  A method of forming a metal film by chemical bath deposition or plating and oxidizing or sulfiding the metal film is also preferable in that the p-type semiconductor portion 7 can be easily formed. The electrolytic deposition method is also preferable because it can be easily formed and the film formation rate is high. Furthermore, the chemical bath deposition method, the plating method, and the electrolytic deposition method are preferable in that the p-type semiconductor portion can be formed even inside the porous portion of the n-type semiconductor portion 6. On the other hand, since these methods involve a change in pH and heating, the dye 9 tends to be detached. For this reason, the formation method of the p-type semiconductor part 7 is suitably selected according to the desired performance or the like.

  The counter electrode 5 is layered on the surface of the p-type semiconductor portion 7 (semiconductor layer 4). The material for forming the counter electrode 5 is not particularly limited as long as it has conductivity, but metals such as Pt, Al, Au, Cu, Ti, Ni, metal oxide, carbon, and the like can be used. The counter electrode 5 can be formed by a known method such as sputtering or vapor deposition. Further, the film thickness (average film thickness) of the counter electrode 5 can be set to, for example, 10 nm or more and 1 μm or less.

  The light response element 10 is irradiated with light such as sunlight, whereby a potential difference is generated between both electrodes (the conductive film 2 and the counter electrode 5), and light can be converted into electric power. Specifically, the dye 9 absorbs light by light irradiation, and electrons and holes are generated. Electrons move from the dye 9 to the conductive film 2 through the porous body 8 (titanium oxide or zinc oxide) and the short-circuit prevention layer 3. On the other hand, the holes move from the dye 9 to the counter electrode 5 via the p-type semiconductor portion 7. By connecting the two electrodes with a conductive wire, a current flows. The photoresponsive element 10 is excellent in durability and photoresponsiveness as described above. Therefore, the photoresponsive element 10 can be suitably used as an optical sensor, a solar cell, or the like.

  The manufacturing method of the photoresponsive element 10 is not particularly limited, and can be obtained, for example, by laminating each layer in order by a known method. The specific method for laminating each layer is as described above.

  2 includes a transparent substrate 1, a conductive film 2, a short-circuit prevention layer 3, a semiconductor layer 14, and a counter electrode 5. Since the transparent substrate 1, the conductive film 2, the short-circuit prevention layer 3, and the counter electrode 5 are the same as those of the photoresponsive element 10 in FIG.

  The semiconductor layer 14 has an n-type semiconductor portion 6 and a p-type semiconductor portion 17 formed from a metal oxide. The n-type semiconductor portion 6 is the same as the photoresponsive element 10 in FIG. Unlike the n-type semiconductor portion 7 of the photoresponsive element 10 in FIG. 1, the n-type semiconductor portion 17 has a structure that penetrates into the hole of the porous n-type semiconductor portion 6. According to the photoresponsive element 20, since the p-type semiconductor portion 17 penetrates into the hole of the n-type semiconductor portion 6 in this way, the contact area between the p-type semiconductor portion 17 and the n-type semiconductor portion 6 is increased. Is wide and can exhibit higher photoresponsiveness. Such a semiconductor layer 14 can be formed by adjusting the average pore diameter of the n-type semiconductor portion 6 or selecting a method for forming the p-type semiconductor portion.

  The photoresponsive element of the present invention is not limited to the above embodiment. For example, a transparent conductive material may be used as the counter electrode to have a structure that senses light from both sides.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.

[Example 1]
A glass substrate (transparent substrate) on which 300 nm of FTO as a transparent conductive film was laminated was prepared. On the surface of this conductive film, a 100 nm TiO ₂ dense layer was laminated as a short-circuit prevention layer by sputtering. Further, a TiO ₂ particle having an average particle diameter of 75 nm was used on the surface of the short-circuit prevention layer to form a porous body having a thickness of 2 μm. Specifically, the porous body was formed by applying the paste of TiO ₂ particles to the surface of the short-circuit prevention layer and sintering at 500 ° C. The part containing the obtained porous body was immersed in a dye-containing solution for 3 hours, and the dye was adsorbed on the TiO ₂ surface to form an n-type semiconductor part (film thickness: 2 μm). As the dye-containing solution, a 0.05 mM solution of Ruthenizer 535-bisTBA manufactured by Solaronix was used. Then, 100 nm of NiO (band gap 3.88 eV) was laminated on the surface of the n-type semiconductor portion by a sputtering method using an oxide target to form a p-type semiconductor portion. Further, 50 nm of Au was laminated as a counter electrode on the surface of the p-type semiconductor portion by a sputtering method to obtain the photoresponsive element of Example 1. FIG. 3 shows an SEM photograph of the semiconductor layer (n-type semiconductor portion and p-type semiconductor portion) of Example 1.

[Examples 2 to 4]
As a material for forming the p-type semiconductor portion, Bi ₂ O ₃ (band gap 3.81 eV: Example 2), PdO (band gap 1.6 eV: Example 3), and CuO (band gap 1. 7eV: The photoresponsive elements of Examples 2 to 4 were obtained in the same manner as in Example 1 except that Example 4) was used.

[Examples 5 and 6]
Except that the film thickness of the n-type semiconductor portion (porous layer) was 6 μm (Example 5) and 10 μm (Example 6), the same operations as in Example 1 were performed, and the light of Examples 5 and 6 A response element was obtained.

  In the photoresponsive elements of Examples 1, 5, and 6, after the n-type semiconductor portion was formed, the optical absorptance with respect to a wavelength of 530 nm (the absorption maximum wavelength of Ruthenizer 535-bisTBA) was measured. The measurement results are shown in FIG. It can be seen that when the film thickness of the n-type semiconductor portion is 2 μm to 6 μm, the absorptance increases with the film thickness, but the increase in the absorption rate reaches a peak at 6 μm and hardly changes from 6 μm to 10 μm.

[Evaluation 1]
About each photoresponsive element of obtained Examples 1-4, the current value change before light irradiation at the time of light irradiation was measured using the cool beam lamp 120W by Toshiba Corporation. The measurement results are shown in Table 1.

[Evaluation 2]
About each photoresponsive element of the obtained Examples 1, 5, and 6, the change in electric current value before and during light irradiation was measured using a cool beam lamp 120W manufactured by Toshiba Corporation. The measurement results are shown in Table 2.

As shown in Tables 1 and 2, it can be seen that any of the photoresponsive elements has photoresponsiveness. In particular, as shown in Table 1, when Examples 1 to 4 are compared, when NiO and Bi ₂ O ₃ having a wide band gap are used as the p-type semiconductor material, a current value of 0.1 mA or more is obtained. ing. On the other hand, when PdO and CuO having a narrow band gap are used, a current value can be obtained only about 1/3 of that when Bi ₂ O ₃ is used.

  Further, as shown in Table 2, when Examples 1, 5, and 6 are compared, it can be seen that the current value becomes maximum when the film thickness is 6 μm. This is considered to be because the balance between the light absorption amount of the dye and the resistance becomes appropriate.

  The photoresponsive element of the present invention is excellent in durability and photoresponsiveness, and can be suitably used as an optical sensor, a solar cell, or the like.

DESCRIPTION OF SYMBOLS 1 Transparent substrate 2 Conductive film 3 Short-circuit prevention layer 4, 14 Semiconductor layer 5 Counter electrode 6 N-type semiconductor part 7, 17 p-type semiconductor part 8 Porous body 9 Dye 10, 20 Photoresponsive element

Claims (10)

A transparent substrate, a conductive film, a short-circuit prevention layer, a semiconductor layer and a counter electrode are laminated in this order,
The semiconductor layer is
A porous body disposed on the surface of the short-circuit prevention layer, and an n-type semiconductor portion having a dye attached to the surface of the porous body;
A p-type semiconductor portion disposed between the n-type semiconductor portion and the counter electrode,
The porous body of the n-type semiconductor part is formed from titanium oxide or zinc oxide,
The p-type semiconductor portion is formed of a metal oxide.   2. The photoresponsive element according to claim 1, wherein a band gap of the metal oxide forming the p-type semiconductor portion is 3 eV or more and 4 eV or less. The p-type semiconductor portion is formed of nickel oxide or bismuth oxide;
The nickel oxide contains 0.8 atom or more and 1.2 atom or less of oxygen with respect to 1 atom of nickel, and the bismuth oxide contains 1.3 atom or more and 1.7 atom or more of oxygen with respect to 1 atom of bismuth. The photoresponsive element according to claim 1 or 2 containing atoms or less.   The photoresponsive element according to claim 1, wherein the p-type semiconductor portion is formed by a sputtering method.   The photoresponsive element according to any one of claims 1 to 4, wherein the p-type semiconductor part is non-porous.   The photoresponsive element according to any one of claims 1 to 5, wherein the p-type semiconductor portion is formed in a layer shape.   The photoresponsive element according to any one of claims 1 to 6, wherein the n-type semiconductor portion has a porous shape with an average pore diameter of 10 nm to 50 nm.   The optical response according to any one of claims 1 to 7, wherein particles having an average particle diameter of 50 nm or more and 100 nm or less made of titanium oxide or zinc oxide are used for forming the porous body of the n-type semiconductor portion. element.   The titanium oxide contains 1.8 to 2.2 atoms of oxygen with respect to 1 atom of titanium, and the zinc oxide has oxygen of 0.8 to 1.2 atoms with respect to 1 atom of zinc. The photoresponsive element according to claim 1, comprising not more than atoms.   The photoresponsive element according to any one of claims 1 to 9, wherein the n-type semiconductor part is formed in layers, and the film thickness of the n-type semiconductor part is 2 µm or more and 10 µm or less.