JP2013042058A - Method of manufacturing quantum dot carrying porous n-type semiconductor, quantum dot carrying porous n-type semiconductor, electrode for quantum dot dye-sensitized solar cell, and quantum dot dye-sensitized solar cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a quantum dot carrying porous n-type semiconductor in which a quantum dot being a semiconductor nano particle is carried on a porous n-type semiconductor, capable of efficiently controlling a quantum dot containing 16-th group element for carrying, and to provide a quantum dot carrying porous n-type semiconductor obtained by the manufacturing method, an electrode for a quantum dot dye-sensitized solar cell, and a quantum dot dye-sensitized solar cell.SOLUTION: The method of manufacturing a quantum dot carrying porous n-type semiconductor in which a quantum dot being a semiconductor nano particle is carried on a porous n-type semiconductor includes a step in which a porous n-type semiconductor is radiated with light under such condition as it is submerged in a 16-th group element compound contained solution, and then a step in which a 16-th group element carrying porous n-type semiconductor obtained through the aforementioned step is radiated with light under such condition as it is submerged in a metal ion contained solution.

Description

  The present invention relates to a method for producing a quantum dot-carrying porous n-type semiconductor, a quantum dot-carrying porous n-type semiconductor, a quantum dot-sensitized solar cell electrode, and a quantum dot-sensitized solar cell.

  In recent social situations, in addition to solving resources depletion and global warming due to the massive consumption of fossil fuels, establishment of a stable power supply means is strongly demanded.

  As such a stable power supply means, much attention has been focused on solar cells and hydrogen production photoelectrochemical cells that can directly convert inexhaustible solar energy into electrical energy and chemical energy.

  In addition to being inexpensive, the dye-sensitized solar cell has a relatively high photoelectric conversion efficiency. For this reason, the dye-sensitized solar cell is attracting great expectations as a next-generation sustainable energy supply source (see Patent Document 1).

  However, in dye-sensitized solar cells, organic dye sensitizers are easily decomposed, and in particular, their lifetime and durability are not sufficient in the presence of oxygen, and the wavelength range that can be absorbed is generally from ultraviolet to visible light. Therefore, there is a problem that it is difficult to achieve more efficient photoelectric conversion.

  Recently, quantum dot-sensitized solar cells in which quantum dots, which are semiconductor nanoparticles, are supported on a semiconductor electrode have been reported (see Patent Documents 2 and 3). Quantum dots are more durable than organic dye sensitizers and are nano-order semiconductor particles, so the effect of multi-exciton generation (MEG) improves solar energy capture efficiency and increases particle size. There is an advantage that the absorption wavelength can be controlled by the control. In particular, since quantum dots are nano-order sized semiconductor particles, it is important that solar energy capture efficiency is improved by the effect of multi-exciton generation (MEG). For example, chalcogenide semiconductors are formed as nanoparticles on a semiconductor electrode. In contrast to the case where the film is present as a film (see Patent Document 4), the solar energy capture efficiency is remarkably improved when quantum dots that are semiconductor nanoparticles are used.

  As a method for supporting quantum dots on a semiconductor electrode, (1) a method in which quantum dots are prepared in advance and then supported on an electrode using a coupling molecule such as mercaptoacetic acid (see Non-Patent Documents 1 and 2), ( 2) A method of precipitation in a chemical bath (see Non-Patent Documents 3 to 5), (3) A method of precipitation by a SILAR (Successive Ionic Layer Adsorption and Reaction) method (see Non-Patent Documents 6 and 7) is known. Yes.

  However, the method (1) has a problem in that the electron transfer efficiency is poor because organic substances exist between the quantum dots and the electrodes. In addition, the above methods (2) and (3) have a problem that the reproducibility is poor and a problem that the solar energy capture efficiency is not a sufficient level for practical use.

  Recently, as a method for supporting quantum dots, which are semiconductor nanoparticles, on a porous n-type semiconductor electrode, a method of irradiating light with the porous n-type semiconductor electrode immersed in a metal ion-containing solution has been proposed ( (See Patent Document 5).

  Such a quantum dot carrying method by light irradiation is referred to as a photodeposition method (PD method: Photodeposition method). In Patent Document 5, as a method of supporting quantum dots, which are semiconductor nanoparticles, on a porous n-type semiconductor electrode, photoprecipitation is performed by irradiating light in a state where the porous n-type semiconductor electrode is immersed in a metal ion-containing solution. Quantum dot-sensitized solar cells for constructing quantum dot-sensitized solar cells that have much better solar energy capture efficiency than conventional ones by adopting the method (PD method) A battery electrode may be provided.

  In the photodeposition method (PD method), (1) the particle size of the quantum dots can be controlled by adjusting the light irradiation time and the concentration of the surface modifier, (2) high reproducibility, and easy to prepare, (3 ) Smooth charge transfer is ensured by direct interface bonding between the porous n-type semiconductor and the quantum dots.

  However, in the quantum dot carrying method described in Patent Document 5, it may be difficult to efficiently carry and carry depending on the type of quantum dots. In particular, quantum dots containing Group 16 elements are very difficult to efficiently control and support.

Japanese Patent Laid-Open No. 2005-19130 JP 2008-16369 A JP 2008-287900 A JP 2009-70768 A JP 2011-91032 A J. et al. Am. Chem. Soc. , 128, 2385. J. et al. Phys. Chem. B, 2006, 110, 9556. J. et al. Phys. Chem. 98, 5338. J. et al. Photochem. Photobiol. A, 181, 306, 2006. Appl. Phys. Lett. , 91, 23116, 2007. Appl. Surf. Sci. 22/3, 1061, 1985. J. et al. Electrochem. Soc. , 137, 2915, 1990.

  An object of the present invention is a method for producing a quantum dot-carrying porous n-type semiconductor in which quantum dots that are semiconductor nanoparticles are carried on a porous n-type semiconductor, and the efficiency of quantum dots containing a group 16 element. An object of the present invention is to provide a method for producing a quantum dot-supporting porous n-type semiconductor that can be well controlled and supported. Moreover, it is providing the quantum dot carrying | support porous n-type semiconductor obtained by such a manufacturing method. Furthermore, to provide a quantum dot-sensitized solar cell electrode including such a quantum dot-supporting porous n-type semiconductor, and a quantum dot-sensitized solar cell including such a quantum dot-sensitized solar cell electrode is there.

The production method of the present invention comprises:
A method for producing a quantum dot-carrying porous n-type semiconductor in which quantum dots that are semiconductor nanoparticles are carried on a porous n-type semiconductor,
After the step (I) of irradiating light with the porous n-type semiconductor immersed in the Group 16 element compound-containing solution,
A step (II) is performed in which the group 16 element-supporting porous n-type semiconductor obtained in the step (I) is irradiated with light in a state of being immersed in a metal ion-containing solution.

  In a preferred embodiment, the light irradiation is ultraviolet irradiation.

  According to another aspect of the present invention, a quantum dot-supporting porous n-type semiconductor is provided. The quantum dot-supporting porous n-type semiconductor of the present invention can be obtained by the production method of the present invention.

  According to another aspect of the present invention, a quantum dot-sensitized solar cell electrode is provided. The quantum dot-sensitized solar cell electrode of the present invention includes the quantum dot-supporting porous n-type semiconductor of the present invention.

  According to another aspect of the present invention, a quantum dot-sensitized solar cell is provided. The quantum dot-sensitized solar cell of the present invention includes the quantum dot-sensitized solar cell electrode of the present invention.

  According to the present invention, there is provided a method for producing a quantum dot-carrying porous n-type semiconductor in which quantum dots that are semiconductor nanoparticles are carried on a porous n-type semiconductor, wherein the quantum dots containing group 16 elements are efficient. It is possible to provide a method for producing a quantum dot-carrying porous n-type semiconductor that can be well controlled and carried. Moreover, the quantum dot carrying | support porous n-type semiconductor obtained by such a manufacturing method can be provided. Furthermore, it is possible to provide a quantum dot-sensitized solar cell electrode including such a quantum dot-supporting porous n-type semiconductor, and a quantum dot-sensitized solar cell including such a quantum dot-sensitized solar cell electrode. it can.

3 is a TEM photograph of a Group 16 element-supporting porous n-type semiconductor obtained after the first step in Example 1. FIG. 3 is a TEM photograph of a quantum dot-supporting porous n-type semiconductor obtained after the second step in Example 1. FIG. XRD patterns of the porous n-type semiconductor before the first step, the group 16 element-supporting porous n-type semiconductor after the first step, and the quantum dot-supporting porous n-type semiconductor after the second step in Example 1 FIG. In Example 1, it is a Se3d-XPS spectrum figure of the porous n-type semiconductors in each reaction step. In Example 1, it is a Pb4f-XPS spectrum figure of the porous n-type semiconductors in each reaction step. In Example 1, it is a UV-Vis spectrum figure of porous n-type semiconductors in each reaction step of the 1st process. 2 is a UV-Vis spectrum diagram of porous n-type semiconductors at each reaction stage in Example 1. FIG. 6 is a TEM photograph of a quantum dot-supporting porous n-type semiconductor obtained after the second step in Example 2. FIG.

≪Method of manufacturing porous n-type semiconductor supporting quantum dots≫
The production method of the present invention is a method for producing a quantum dot-carrying porous n-type semiconductor in which quantum dots, which are semiconductor nanoparticles, are carried on a porous n-type semiconductor. After the step (I) of irradiating light in the state of being immersed in the element compound-containing solution, the light is applied in the state where the group 16 element-supporting porous n-type semiconductor obtained in the step (I) is immersed in the metal ion-containing solution. Irradiation step (II) is performed.

  The production method of the present invention may include any other appropriate step as long as the step (II) is performed after the step (I) as long as the effects of the present invention are not impaired.

  Any appropriate porous n-type semiconductor can be adopted as the porous n-type semiconductor. Such a porous n-type semiconductor is preferably a porous n-type semiconductor having a photocatalytic action.

Preferred examples of the porous n-type semiconductor include titanium oxide (TiO ₂ ), zinc oxide (ZnO), and strontium titanate (SrTiO ₃ ). As the porous n-type semiconductor, titanium oxide (TiO ₂ ) is particularly preferable. This is because titanium oxide (TiO ₂ ) has an excellent photocatalytic action, and thus, when irradiated with light in the production method of the present invention, quantum dots are likely to precipitate due to the photocatalytic action.

  The porous n-type semiconductor may have a conductive film. Examples of such a conductive film include ITO (indium tin oxide), FTO (fluorine-doped tin oxide), ATO (antimony-doped tin oxide), and the like.

  The porous n-type semiconductor may be provided with a support substrate as necessary. Any appropriate support substrate can be adopted as the support substrate. For example, a glass substrate, a plastic substrate, etc. are mentioned.

  Any appropriate compound can be adopted as the Group 16 element compound as long as it is a compound having a Group 16 element. Examples of the Group 16 element include S, Se, and Te.

Examples of Group 16 element compounds containing S as a Group 16 element include S ₈ , H ₂ SO ₄ , H ₂ SO ₃ , H ₂ S ₂ O ₃ , Na ₂ SO ₄ , Na ₂ SO ₃ , and Na _2. S ₂ O _{3 and the} like can be mentioned.

Examples of Group 16 element compounds containing Se as a Group 16 element include H ₂ SeO ₃ , H ₂ SeO ₄ , H ₂ SeO ₅ , Na ₂ SeO ₃ , Na ₂ SeO ₄ , and Na ₂ SeO _5. It is done.

Examples of the Group 16 element compound containing Te as the Group 16 element include TeO, TeO ₂ , TeO ₃ , H ₂ TeO ₃ , H ₂ TeO ₄ , Na ₂ TeO ₃ , and Na ₂ TeO ₄ .

  The group 16 element compound-containing solution may contain any appropriate solvent. Examples of such a solvent include alcohols such as methanol and ethanol.

Any appropriate content ratio can be adopted as the content ratio of the Group 16 element compound in the Group 16 element compound-containing solution as long as the effects of the present invention are not impaired. Such content, for example, preferably in the range of ^{0.001 × 10 -3 mol / L~1000 ×} 10 -3 mol / L.

  Examples of the metal ions include Cd ions, Pb ions, Mo ions, Ag ions, Bi ions, Cu ions, In ions, Ga ions, Ge ions, Si ions, Zn ions, and Fe ions.

  The metal ion-containing solution can contain any suitable solvent. Examples of such a solvent include alcohols such as methanol and ethanol.

Any appropriate content ratio can be adopted as the content ratio of the metal ions in the metal ion-containing solution as long as the effects of the present invention are not impaired. Such content, for example, preferably in the range of ^{0.001 × 10 -3 mol / L~1000 ×} 10 -3 mol / L.

The metal ion-containing solution may contain mercaptoacetic acid in order to adjust the particle size of the quantum dots. When containing mercaptoacetic acid, the content concentration of the metal ion-containing solution, the initial concentration, preferably in the range of ^{0.001 × 10 -3 mol / L~1000 ×} 10 -3 mol / L, more preferably in the range of ^{0.01 × 10 -3 mol / L~100 ×} 10 -3 mol / L, more ^{preferably, 0.1 × 10 -3 mol / L~10} × 10 -3 mol / L Range. If the concentration (initial concentration) of mercaptoacetic acid in the metal ion-containing solution is within the above range, photoinduced electron transfer from the quantum dots to the porous n-type semiconductor is sufficiently promoted and the particle size is small. It is also possible to suppress a decrease in light absorption due to the quantum size effect due to being too much.

  In the step (I), light irradiation is performed in a state where the porous n-type semiconductor is immersed in the Group 16 element compound-containing solution.

  As light irradiation in the said process (I), irradiation of the light of arbitrary appropriate wavelengths can be employ | adopted. Preferably, the porous n-type semiconductor is irradiated with light having a wavelength exhibiting a photocatalytic action. Typically, it is preferable to irradiate with ultraviolet rays.

  The light irradiation in the step (I) can be performed under any appropriate temperature condition.

  In the step (I), after the light irradiation, the obtained Group 16 element-supporting porous n-type semiconductor is washed and dried using any appropriate washing solvent as necessary.

  In the step (II), the group 16 element-supporting porous n-type semiconductor obtained in the step (I) is irradiated with light in a state immersed in a metal ion-containing solution.

  As light irradiation in the said process (II), irradiation of the light of arbitrary appropriate wavelengths can be employ | adopted. Preferably, the porous n-type semiconductor is irradiated with light having a wavelength exhibiting a photocatalytic action. Typically, it is preferable to irradiate with ultraviolet rays.

  The light irradiation in the step (II) can be performed under any appropriate temperature condition.

  In the step (II), after the light irradiation, the obtained quantum dot-supporting porous n-type semiconductor is washed and dried using any appropriate washing solvent as necessary.

  According to the production method of the present invention, the step (I) of irradiating the porous n-type semiconductor in a state in which the porous n-type semiconductor is immersed in the group 16 element compound-containing solution, and the group 16 element support obtained in the step (I) Quantum dots containing a group 16 element are efficiently controlled and carried by two steps of the step (II) in which the porous n-type semiconductor is immersed in a metal ion-containing solution and irradiated with light (II). A quantum dot-supported porous n-type semiconductor can be provided.

≪Quantum dot supported porous n-type semiconductor≫
In the quantum dot-supporting porous n-type semiconductor obtained by the production method of the present invention, quantum dots that are semiconductor nanoparticles are supported on the porous n-type semiconductor. As a quantum dot which is such a semiconductor nanoparticle, a chalcogenide semiconductor nanoparticle is mentioned, for example. Examples of chalcogenide semiconductor nanoparticles include CdS, MoS, FeS, In ₂ S ₃ , NaInS ₂ , ZnIn ₂ S ₄ , Zn _x Cd _1-x S, Cd ₂ In ₂ S ₄ , AgGaS ₂ , PbS, and Ag ₂ S. Metal selenide nanoparticles such as CdSe, PbSe, CuInSe ₂ , CuInGaSe ₂ and CuInGaSe; metal telluride nanoparticles such as CdTe; and the like.

  If the particle diameter of the quantum dot which is the said semiconductor nanoparticle is a nano order, it can take arbitrary appropriate magnitude | sizes. For example, it is preferably in the range of 1 nm to 20 nm, and more preferably in the range of 1 nm to 10 nm. If the particle diameter of the quantum dots that are the semiconductor nanoparticles falls within such a range, the solar energy capture efficiency can be effectively improved by the effect of multi-exciton generation (MEG).

≪Quantum dot sensitized solar cell electrode≫
The electrode for quantum dot-sensitized solar cells of the present invention includes a quantum dot-supporting porous n-type semiconductor obtained by the production method of the present invention. In the quantum dot-supporting porous n-type semiconductor obtained by the production method of the present invention, quantum dots containing a Group 16 element are efficiently controlled and supported on the porous n-type semiconductor. For this reason, compared with the conventional electrode for quantum dot sensitized solar cells, it can become an electrode suitable for the quantum dot sensitized solar cell excellent in the solar energy capture | acquisition efficiency evaluated by IPCE, power conversion efficiency, etc.

≪Quantum dot sensitized solar cell≫
The quantum dot-sensitized solar cell of the present invention includes the quantum dot-sensitized solar cell electrode of the present invention.

  The quantum dot-sensitized solar cell of the present invention typically has a configuration including the quantum dot-sensitized solar cell electrode of the present invention and a counter electrode. The counter electrode may be provided with a support substrate as necessary.

  Any appropriate counter electrode can be adopted as the counter electrode. For example, titanium, nickel, gold, silver, copper, carbon, a transparent electrode, a conductive polymer, and the like can be given. Examples of the transparent electrode include those described above. Examples of the conductive polymer include polyacetylene, polyacene, polypyrrole, polythiophene, and derivatives thereof doped with chlorine, bromine, or iodine.

  Any appropriate support substrate can be adopted as the support substrate. For example, a glass substrate, a plastic substrate, etc. are mentioned.

  The quantum dot-sensitized solar cell of the present invention may be in the form of a wet solar cell or a dry solar cell. An electrolyte may be interposed between the quantum dot-sensitized solar cell electrode of the present invention and the counter electrode. As the electrolyte, a liquid electrolyte or a solid electrolyte may be used. Any appropriate liquid electrolyte can be adopted as the liquid electrolyte. Any appropriate solid electrolyte can be adopted as the solid electrolyte.

  Since the quantum dot-sensitized solar cell of the present invention uses the quantum dot-sensitized solar cell electrode of the present invention, the IPCE is extremely high. Specifically, the quantum dot-sensitized solar cell of the present invention has an IPCE of preferably 70% or more, more preferably 72% or more, still more preferably 75% or more, particularly preferably 77% or more, and most preferably 80%. % Or more. Even if the IPCE of the conventional quantum dot-sensitized solar cell is relatively high, it is usually 40 to 50%, and particularly high performance is around 60% (see, for example, Patent Documents 2 and 3). . For this reason, the quantum dot-sensitized solar cell of the present invention can realize extremely high IPCE.

  Since the quantum dot-sensitized solar cell of the present invention uses the quantum dot-sensitized solar cell electrode of the present invention, it exhibits a high level of power conversion efficiency that can be recognized as being highly feasible for practical use in the future. it can. Specifically, the quantum dot-sensitized solar cell of the present invention has a power conversion efficiency of preferably 1.25% or more, more preferably 1.5% or more, still more preferably 1.75% or more, particularly preferably. 2% or more.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited by these Examples.

[Production Example 1]: Production of porous titanium oxide thin film Titanium oxide particles (manufactured by JGC Catalysts & Chemicals Co., Ltd., PST-18NR, particle size = 20 nm) are glass substrates with FTO (fluorine-doped tin oxide) conductive film (surface resistance = 12Ω) / □) by a doctor blade method and firing at 500 ° C. for 1 hour to obtain a porous titanium oxide thin film having a thickness of 1.2 μm and a length and width of 2.5 cm × 4 cm.

[Example 1]
(First step)
The porous titanium oxide thin film (mp-TiO ₂ ) obtained in Production Example 1 was immersed in an ethanol solution of H ₂ SeO ₃ (concentration: 1.36 mM). Argon gas was blown into the solution for 30 minutes under light shielding conditions, and then irradiated with ultraviolet rays at 25 ° C. using a high-pressure mercury lamp for 60 minutes. The light intensity of the high-pressure mercury lamp used was 3.6 mW / cm ² (wavelength = 320 to 400 nm). In this way, a Group 16 element-supporting porous n-type semiconductor (Se / mp-TiO ₂ ) was obtained. The obtained group 16 element-supporting porous n-type semiconductor (Se / mp-TiO ₂ ) was washed with ethanol and dried under reduced pressure at room temperature.
(Second step)
The group 16 element-supporting porous n-type semiconductor (Se / mp-TiO ₂ ) obtained in the first step was immersed in an ethanol solution (concentration: 1.36 mM) of Pb (ClO ₄ ) ₂ . Ultraviolet rays were irradiated for 60 minutes using a high-pressure mercury lamp at 25 ° C. in an argon atmosphere. The light intensity of the high-pressure mercury lamp used was 3.6 mW / cm ² (wavelength = 320 to 400 nm). Thus, a quantum dot-supporting porous n-type semiconductor (PbSe / mp-TiO ₂ ) was obtained. The obtained quantum dot-supporting porous n-type semiconductor (PbSe / mp-TiO ₂ ) was washed with ethanol and dried under reduced pressure at room temperature.
(TEM photograph of Group 16 element-supporting porous n-type semiconductor)
A TEM photograph was taken of the Group 16 element-supporting porous n-type semiconductor (Se / mp-TiO ₂ ) obtained after the first step. The results are shown in FIG.
According to FIG. 1, it can be seen that a nano-order group 16 element (Se) is supported on a porous n-type semiconductor (mp-TiO ₂ ).
(TEM photograph of porous n-type semiconductor supporting quantum dots)
A TEM photograph was taken of the quantum dot-supporting porous n-type semiconductor (PbSe / mp-TiO ₂ ) obtained after the second step. The results are shown in FIG.
As can be seen from FIG. 2, nano-order quantum dots (PbSe) are supported on the porous n-type semiconductor (mp-TiO ₂ ).
(XRD analysis)
Porous n-type semiconductor (mp-TiO ₂ ) before the first step, Group 16 element-supporting porous n-type semiconductor (Se / mp-TiO ₂ ) after the first step, and quantum dot-supporting porous after the second step Each XRD analysis of the high-quality n-type semiconductor (PbSe / mp-TiO ₂ ) was performed. The results are shown in FIG.
In the XRD pattern of the porous n-type semiconductor (mp-TiO ₂ ) before the first step in FIG. 3, it can be seen that there is a diffraction peak derived from anatase-type titanium oxide.
In the XRD pattern of the Group 16 element-supported porous n-type semiconductor (Se / mp-TiO ₂ ) after the first step in FIG. 3, there is a weak diffraction peak that can be attributed to monoclinic Se at 29.6 °. You can see that
In the XRD pattern of the quantum dot-supported porous n-type semiconductor (PbSe / mp-TiO ₂ ) after the second step in FIG. 3, the diffraction peak attributable to the monoclinic system Se disappears, and the cubic system PbSe. It can be seen that there is a diffraction peak that can be assigned to.
In these XRD analyses, Se crystals were photo-deposited on the surface of the porous n-type semiconductor (mp-TiO ₂ ) by ultraviolet irradiation in the first step, and further PbSe quantum dots were photo-deposited by ultraviolet irradiation in the second step. Is shown.
(XPS analysis)
Se3d-XPS spectra of porous n-type semiconductors at each reaction stage were measured. The results are shown in FIG. In addition, Pb4f-XPS spectra of porous n-type semiconductors at each reaction stage were measured. The results are shown in FIG. According to FIG. 4 and FIG. 5, the Se crystal precipitated by the ultraviolet irradiation in the first step gradually decreases its precipitation amount by the ultraviolet irradiation in the second step, and instead, PbSe quantum dots are photodeposited, It can be seen that the amount of precipitation increases.
(UV-Vis analysis)
UV-Vis spectra of porous n-type semiconductors at each reaction stage of the first step were measured. The results are shown in FIG. Moreover, the UV-Vis spectrum of the porous n-type semiconductors in each reaction stage including the first step and the second step was measured. The results are shown in FIG.
According to FIGS. 6 and 7, the absorption edge of the Group 16 element-supported porous n-type semiconductor (Se / mp-TiO ₂ ) is about 630 nm, whereas the quantum dot-supported porous n-type semiconductor (PbSe / Pb) It can be seen that mp-TiO ₂ ) has strong absorption from the visible range to the near infrared range.

[Example 2]
(First step)
In the same manner as in Example 1, a Group 16 element-supporting porous n-type semiconductor (Se / mp-TiO ₂ ) was obtained.
(Second step)
Mercaptoacetic acid (concentration: 4 × 10 ⁻³ mol / L) was added to an ethanol solution of Pb (ClO ₄ ) ₂ (concentration 1.36 mM), and the Group 16 element-supported porous n-type obtained in the first step A semiconductor (Se / mp-TiO ₂ ) was immersed. Ultraviolet rays were irradiated for 60 minutes using a high-pressure mercury lamp at 25 ° C. in an argon atmosphere. The light intensity of the high-pressure mercury lamp used was 3.6 mW / cm ² (wavelength = 320 to 400 nm). Thus, a quantum dot-supporting porous n-type semiconductor (PbSe / mp-TiO ₂ ) was obtained. The obtained quantum dot-supporting porous n-type semiconductor (PbSe / mp-TiO ₂ ) was washed with ethanol and dried under reduced pressure at room temperature.
(TEM photograph of porous n-type semiconductor supporting quantum dots)
A TEM photograph was taken of the quantum dot-supporting porous n-type semiconductor (PbSe / mp-TiO ₂ ) obtained after the second step. The results are shown in FIG.
As can be seen from FIG. 8, nano-order quantum dots (PbSe) are supported on a porous n-type semiconductor (mp-TiO ₂ ).

[Comparative Example 1]
The porous titanium oxide thin film (mp-TiO ₂ ) obtained in Production Example 1 was immersed in an ethanol solution of H ₂ SeO ₃ (concentration 1.36 mM) and Pb (ClO ₄ ) ₂ (concentration 1.36 mM). . Argon gas was blown into the solution for 30 minutes under light shielding conditions, and then irradiated with ultraviolet rays at 25 ° C. using a high-pressure mercury lamp for 60 minutes. The light intensity of the high-pressure mercury lamp used was 3.6 mW / cm ² (wavelength = 320 to 400 nm). In this way, an attempt was made to obtain a quantum dot-supporting porous n-type semiconductor (PbSe / mp-TiO ₂ ), however, only a white precipitate was formed in the ethanol solution, and the surface of the porous titanium oxide thin film No precipitation of PbSe quantum dots on the surface was observed.

  The quantum dot-supported porous n-type semiconductor obtained by the production method of the present invention can be used as an electrode for a quantum dot-sensitized solar cell, and such an electrode for a quantum dot-sensitized solar cell has an extremely high IPCE efficiency, And it can use for the quantum dot sensitized solar cell which shows the high level power conversion efficiency which can be recognized that the future practical use is high.

Claims (5)

A method for producing a quantum dot-carrying porous n-type semiconductor in which quantum dots that are semiconductor nanoparticles are carried on a porous n-type semiconductor,
After the step (I) of irradiating light with the porous n-type semiconductor immersed in the Group 16 element compound-containing solution,
Performing the step (II) of irradiating the group 16 element-supporting porous n-type semiconductor obtained in the step (I) with light immersed in a metal ion-containing solution;
A method for producing a quantum dot-supporting porous n-type semiconductor.   The manufacturing method according to claim 1, wherein the light irradiation is ultraviolet irradiation.   A quantum dot-supporting porous n-type semiconductor obtained by the production method according to claim 1.   An electrode for a quantum dot-sensitized solar cell, comprising the quantum dot-supporting porous n-type semiconductor according to claim 3. The quantum dot sensitized solar cell containing the electrode for quantum dot sensitized solar cells of Claim 4.