JP2005126295A - Tin-containing semiconductive metal oxide and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tin-containing semiconductive metal oxide which can be suitably used for a photocatalyst, a solar battery, a light-emitting device or a photodetector, by drastically expanding the functional wavelength range of a semiconductive metal oxide, whose application has been limited to the ultraviolet range, toward the long-wavelength region. <P>SOLUTION: The tin-containing semiconductive metal oxide is derived from the semiconductive metal oxide which contains an SnO<SB>6</SB>octahedron wherein six oxygen atoms are coordinated to a tetravalent Sn in a crystal structure and has a photoabsorption band within the ultraviolet region. The tin-containing semiconductive metal oxide is obtained by removing one or two oxygen atoms from the SnO<SB>6</SB>octahedron present at the surface or within the semiconductive metal oxide. The tin-containing semiconductive metal oxide has an SnO<SB>5</SB>polyhedron wherein oxygen atoms are pentacoordinated or an SnO<SB>4</SB>tetrahedron structure wherein oxygen atoms are tetracoordinated at its surface or its interior, has a smaller band gap compared to that of the semiconductive metal oxide and has a functional wavelength range which is expanded toward the long-wavelength region. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The invention of this application relates to a tin-containing semiconductor metal oxide and a method for producing the same. More specifically, the invention of this application relates to a tin-containing semiconductor metal oxide that can be suitably used for a photocatalyst, a solar cell, a light-emitting element, or a light-detecting element, and a method for producing the same.

  Currently, global warming is a global problem, which is caused by the rapid increase in atmospheric carbon dioxide. If it continues to increase at the current pace, the global average will rise by 1.4 to 5.8 ° C at the end of the 21st century, and a larger increase is predicted in the region.

  In order to avoid this, hydrogen has recently attracted attention as a clean energy that does not emit carbon dioxide. Hydrogen is considered to be an ideal fuel because it has a thermal efficiency about three times that of gasoline and becomes water after combustion, so that no harmful substances are generated after combustion. Hydrogen is also a fuel for fuel cells, and its generation technology is urgently being developed as a clean energy source. However, it does not make sense to generate carbon dioxide and hazardous waste to generate the hydrogen, or to consume and deplete valuable limited resources in large quantities.

  What is promising is hydrogen generation technology using solar energy. The solar energy that reaches the ground in one year is enormous, equivalent to 10,000 times the annual energy consumption of mankind. One of the methods of utilizing solar energy is an artificial photosynthesis technology that directly produces hydrogen and oxygen as clean fuels from water and inexhaustible sunlight using a semiconductor metal oxide photocatalyst. When the photocatalyst absorbs energy beyond its band gap, it generates holes and electrons, which undergo an oxidation reaction and a reduction reaction with water, respectively, to generate oxygen and hydrogen. Considering the practical application of this photocatalyst, it is important how to efficiently use the visible light region containing much of the solar energy.

  In addition, the application of photocatalysts has begun to be widely studied as a technique for decomposing harmful chemical substances. Examples include the decomposition of organic substances such as pesticides and malodorous substances in water, soil or air, and self-cleaning of solid surfaces such as glass and ceramics by catalytic coating. At present, most of these technologies use titanium dioxide, so they hardly work with visible light. In particular, there is a case where it is necessary to prepare an ultraviolet light source especially for indoor use, and a photocatalyst that works well in the visible light region. Is strongly desired.

  On the other hand, it is well known that Si is used as a solar cell, but recently, solar cells using titanium oxide have been developed. Titanium oxide, which is being widely developed as a photocatalyst, has a large accumulation of know-how such as its manufacturing technology, and it can be said that it is relatively easy to apply to solar cells. However, the power generation wavelength region of titanium oxide is limited to the ultraviolet region, and it is strongly demanded to greatly expand the power generation wavelength region of a titanium oxide solar cell under development and improve its power generation efficiency.

  Up to now, there have been many studies on functional elements using the interaction between transition metal oxides and light, such as photocatalysts and solar cells using transition metal oxides. The band gap was difficult to control. In particular, transition metal oxides with a wide band gap have been considered promising as photocatalysts, but control guidelines for reducing the band gap have not been established, and most of the photocatalytic functions of titanium oxide are still in the ultraviolet region. It has been limited to.

The inventors of this application have also conducted various studies on semiconductor metal oxides so far, and in the case of TiO ₂ , even if oxygen vacancies are formed around Ti, the band gap is not much Ti.
It is found that it is not different from the case of O ₂ bulk (Non-patent Document 1), and the electronic structure of TiO ₂ bulk crystal and the electronic structure of InMO ₄ (M = V, Nb, Ta) or BiVO ₄ bulk crystal Although comparison (Non-patent Document 2) has been performed, control guidelines for reducing the band gap of the semiconductor metal oxide have not been established so far.
Mitsutake Oshikiri, F. Aryasetiawan and M. Boero et al., "Electronic structures of Titanium Oxide Crystal Surface with Lithium Atom on the Surface", Materials Research Society Symposium Proceedings Vol. 654 (2000 MRS Fall Meeting Proceedings), AA5.10.1-AA5. 10.6 Mitsutake Oshikiri, Mauro Boero, Jinhua Ye et al., "Electronic structures of promising photocatalysts InMO4 (M = V, Nb, Ta) and BiVO4 for water decomposition in the visible wavelength region", Journal of Chemical Physics, Vol. 117, Issue 15, pp. 7313-7318, October 15, 2002

  The invention of this application is to provide a tin-containing semiconductor metal oxide controlled so as to have a smaller band gap as compared with semiconductor metal oxides having a large band gap known so far, and a method for producing the same. According to the invention of this application, the photocatalyst, the solar cell, the light emitting element, or the light whose functional wavelength range has been greatly expanded to the long wavelength side compared to the semiconductor metal oxides whose use has been limited to the ultraviolet region so far. An object of the present invention is to provide a tin-containing semiconductor metal oxide that can be suitably used for a detection element and a method for producing the same.

In order to solve the above problems, the invention of this application firstly includes a SnO ₆ octahedron in which _six oxygens are coordinated to tetravalent Sn in the crystal structure, and absorbs light in the ultraviolet region. One or two oxygen atoms are removed from the SnO ₆ octahedron existing on the surface or inside of the semiconductor metal oxide in which the band exists, and the SnO ₅ polyhedron in which the oxygen atoms are pentacoordinated or 4 oxygen atoms are present.
The coordinated SnO ₄ tetrahedral structure exists on the surface or inside, has a band gap smaller than that of the semiconductor metal oxide, and a functional wavelength region is extended to a long wavelength region. A tin-containing semiconductor metal oxide is provided.

  Second, in the first invention, there is provided a tin-containing semiconductor metal oxide characterized by being used in any one of a photocatalyst, a solar cell, a light emitting element, and a light detecting element.

  Thirdly, in the first or second invention, there is provided a tin-containing semiconductor metal oxide characterized in that a promoter or an electrode is supported.

  Fourthly, in the third invention, there is provided a tin-containing semiconductor metal oxide characterized in that the promoter or the electrode is any one of a noble metal, a transition metal and an oxide.

Fifth, in the fourth invention, the promoter or electrode is Pt, Ni, IrO ₂ , Ni
Provided is a tin-containing semiconductor metal oxide characterized by being one of O _x and RuO ₂ .

  Sixth, in any one of the first to fifth inventions, there is provided a tin-containing semiconductor metal oxide characterized by being used as a photocatalyst for oxygen production or a photocatalyst for hydrogen production.

  Seventhly, in any one of the first to fifth inventions, there is provided a tin-containing semiconductor metal oxide characterized by being used as a water splitting photocatalyst.

  Eighth, in any one of the first to fifth inventions, there is provided a tin-containing semiconductor metal oxide characterized by being used as a chemical substance decomposing photocatalyst or a chemical substance producing photocatalyst.

  Ninth, in any one of the first to fifth inventions, there is provided a tin-containing semiconductor metal oxide characterized by being used as a solar cell element used in a power storage device or a power generation device.

  Tenth, in any one of the first to fifth inventions, there is provided a tin-containing semiconductor metal oxide which is used as a light emitting element used in an image display device, a signal device or a communication device.

  Eleventhly, in any one of the first to fifth inventions, there is provided a tin-containing semiconductor metal oxide characterized by being used as a light detecting element used in a light detecting device.

Twelfth, the crystal structure contains SnO ₆ octahedron in which _six oxygen atoms are coordinated with tetravalent Sn and exists on the surface or inside of a semiconductor metal oxide having a light absorption band in the ultraviolet region. One or two oxygen atoms are removed from a SnO ₆ octahedron, and a SnO ₅ polyhedron in which oxygen atoms are pentacoordinated or a SnO ₄ tetrahedral structure in which oxygen atoms are tetracoordinated are present on the surface or inside, and the semiconductor metal Provided is a method for producing a tin-containing semiconductor metal oxide characterized in that the band gap is reduced as compared with an oxide and the functional wavelength region is extended to a long wavelength region.

Thirteenth, by replacing a part or all of the metal element of the semiconductor metal oxide having a light absorption band in the ultraviolet region and not containing Sn with tetravalent Sn, SnO ₆ 8 By forming a plane and removing one or two of the oxygen atoms in the SnO ₆ octahedron, an oxygen pentacoordinate SnO ₅ polyhedron or an oxygen tetracoordinate SnO ₄ tetrahedral structure is formed on the surface or inside. A method for producing a tin-containing semiconductor metal oxide is provided.

  Fourteenth, in the thirteenth invention, a semiconductor metal oxide having a light absorption band in the ultraviolet region and containing no Sn is titanium oxide, zirconium oxide, vanadium oxide, niobium oxide, tantalum oxide, indium oxide, and Provided is a method for producing a tin-containing semiconductor metal oxide, which is any one of zinc oxides.

  Fifteenth, in the eighth invention, there is provided a method for decomposing a harmful chemical substance, characterized by irradiating the hazardous chemical substance with light in the presence of a chemical substance decomposing photocatalyst.

  According to the invention of this application, the functional wavelength range of a semiconductor metal oxide used as a photocatalyst, a solar cell, a light emitting element, or a light detecting element has been limited to the ultraviolet region. Therefore, it is possible to provide a tin-containing semiconductor metal oxide that can be suitably used as a highly functional and highly efficient photocatalyst, solar cell, light emitting element, and light detecting element, and a method for producing the same.

  The invention of this application has the features as described above, and an embodiment thereof will be described below.

Include SnO ₆ octahedra oxygen six tetravalent Sn in the crystal structure is coordinated, and a semiconductor metal oxide present light absorption band in the ultraviolet region, from SnO ₆ octahedra present inside or on the surface One or two oxygen atoms are removed, and a SnO ₅ polyhedron in which oxygen atoms are pentacoordinated or a SnO ₄ tetrahedral structure in which oxygen atoms are tetracoordinated is present on the surface or inside, and the semiconductor metal oxide Compared to products, the band gap is small and the functional wavelength region is extended to a long wavelength region (for example, a visible light region).

The tin-containing semiconductor metal oxide of the invention of this application includes a semiconductor metal oxide having a light absorption band in the ultraviolet region, including SnO ₆ octahedron in which _six oxygen atoms are coordinated with tetravalent Sn in the crystal structure. Since defects are created by removing one or two coordinated oxygen elements of SnO ₆ octahedron existing on the surface or inside of the structure, the band gap is reduced by having such a structure. The functional wavelength range of the semiconductor metal oxide, which has been limited to the ultraviolet region, which has been used as a photocatalyst, a solar cell, a light emitting element or a light detecting element so far, has been greatly expanded to the long wavelength side, for example, the visible light region. It is.

In addition, even if it does not intentionally make the above-mentioned defects, it may be a substance that causes such a defect in manufacturing technology, or a substance that naturally causes such a defect, or an intention. to instead of producing defects removing the oxygen atom, can be regarded as obtained by removing one or two oxygen atoms from SnO ₆ octahedra, oxygen is 5 coordinating SnO ₅ polyhedral or oxygen tetracoordinate The SnO ₄ tetrahedral structure may exist on the surface or inside.

  According to the invention of this application, the tin-containing semiconductor metal whose functional wavelength region is extended to the long wavelength side such as the visible light region, for example, compared to the semiconductor metal oxide whose functional wavelength range has been limited to the ultraviolet region so far. An oxide is obtained, and by using this tin-containing semiconductor metal oxide, the functional wavelength range of the photocatalyst, the solar cell, and the light-emitting element can be broadened, and visible light containing a lot of solar energy. The area can be used efficiently.

  The tin-containing semiconductor metal oxide of the invention of this application can be suitably used as a photocatalyst for oxygen production, a photocatalyst for hydrogen production, or a photocatalyst for water splitting, and further, a catalyst for chemical substance decomposition or a chemical substance production It can also be suitably used as a photocatalyst.

  In the case of applying the tin-containing semiconductor metal oxide of the invention of this application as a photocatalyst, it is desirable that the surface area be increased by forming fine particles in order to effectively use light. For example, an oxide prepared by a solid phase reaction method has large particles and a small surface area, but the particle size can be reduced by grinding with a ball mill or the like. Various thin film forming techniques can be used to manufacture and use in the form of a thin film, or it can be used by coating other materials into a thin film. Further, the catalyst material may be applied to a self-cleaning technique by kneading it into a wall material or the like.

  In addition, the reaction solution used for the water decomposition reaction is not limited to pure water, and is usually mixed with salts and sacrificial agents that do not deteriorate the catalyst material, as is often used for water decomposition reaction. Water may be used. The wavelength of the light to be irradiated needs to include light having a wavelength in a region where the semiconductor is absorbed. In the invention of this application, sunlight may be irradiated.

The photocatalyst using the tin-containing semiconductor metal oxide of the invention of this application can be applied not only to water decomposition but also to many photocatalytic reactions. For example, in the case of decomposing organic substances, alcohol, agricultural chemicals, malodorous substances, etc. generally act as electron donors and are oxidatively decomposed by holes. As a reaction form, the catalyst may be suspended in an aqueous solution containing an organic substance and irradiated with light, or the catalyst may be fixed to a substrate. A gas phase reaction may be used, such as decomposition of malodorous substances. Further, the tin-containing semiconductor metal oxide of the invention of this application can be applied to elementary reaction processes in the production process of various molecules by utilizing the selective reactivity of the photocatalytic reaction.

  In addition, when using the tin-containing semiconductor metal oxide of the invention of this application as a photocatalyst for chemical substance decomposition, the harmful chemical substance is decomposed by irradiating light to the harmful chemical substance in the presence of the photocatalyst for chemical substance decomposition. It becomes possible to do.

As mentioned above, when applying to a photocatalyst, it is desirable to apply the invention of this application to the surface from the inside or near the surface within a depth of 100 mm from the surface. In addition, the surface of the tin-containing semiconductor metal oxide can be modified by supporting the promoter or the electrode on the tin-containing semiconductor metal oxide. In particular, the promoter or the electrode is a precious metal, transition metal or oxide. More preferably, the promoter or electrode is Pt, Ni, IrO _2.
, NiO _x, and RuO ₂ , and by supporting the promoter or the electrode in this way, excited electrons can be spatially separated, and more photocatalyst, solar cell The efficiency of the light emitting element or the detecting element can be increased. The supporting method can be carried out by an impregnation method or a photo-deposition method.

  Furthermore, the tin-containing semiconductor metal oxide of the invention of this application can be expected to be suitably used as a solar cell element used in a power storage device or a power generation device. Since the wavelength sensitivity region of the tin-containing semiconductor metal oxide of the invention of this application is extended to the long wavelength side, when used as a solar cell element, it is a matter of course that high efficiency can be expected, but electrons are extracted. An improvement in the performance of the electrode on the side can also be expected. For example, in the case where the invention of this application is introduced when the base semiconductor metal oxide is titanium oxide, the titanium oxide, which is the base semiconductor metal oxide, absorbs ultraviolet rays, and the electrons are From the feature, it is easy to move to the orbit where Sn's 5s orbit having oxygen defects on the surface or inside contributes greatly. Furthermore, since the 5s orbit of Sn greatly expands spatially, depending on the Sn spatial arrangement, high electrical conductivity can be advantageously provided. Since many transition metal oxides having a light absorption band in the ultraviolet region often have a low ability to move electrons, the introduction of the invention of this application introduces the wavelength sensitivity region of such materials as solar cells on the long wavelength side. In addition to expansion, the performance can be expected to be improved by reducing the internal resistance of the solar cell.

In addition, it is already well known to use a GaN semiconductor as a blue light-emitting element. However, the crystal structure includes a SnO ₆ octahedron in which _six oxygen atoms are coordinated with tetravalent Sn, and light in the ultraviolet region. If the invention of this application is applied to a tin-containing semiconductor metal oxide having an absorption band or a semiconductor metal oxide having a light absorption band in an ultraviolet region not containing tin, light in the visible light region is emitted from the ultraviolet ray. A light emitting element (light emitting device) can be manufactured. The degree of freedom in adjusting the emission wavelength is also great depending on the choice of the host crystal.

  Therefore, the tin-containing semiconductor metal oxide of the invention of this application can be used as a light-emitting element, and various host crystals can have a light-emitting function in the visible region. The application range is wide, such as providing a light emitting function to pixels of image display devices and wall materials of building materials. Further, it can be used for a light conversion element that emits visible light when ultraviolet light is incident, a light-emitting element that uses ultraviolet light as an energy source, and the like.

  The invention of this application can also be used as a light detection element in the ultraviolet or visible light region. The mechanism is almost the same as that of solar cells in principle. That is, the tin-containing semiconductor metal oxide of the invention of this application may be able to automatically convert invisible ultraviolet light into visible light due to the characteristics of its electronic structure. The use as an ultraviolet light detection element used in a detection device for informing the presence is also conceivable. In addition, the response wavelength range of many metal oxides, whose conversion to electrical signals was limited to light in the ultraviolet region, can be extended to the visible light region, and it can be used as a photodetection element for visible light. It spreads.

On the other hand, the method for producing a tin-containing semiconductor metal oxide according to the invention of this application includes a SnO ₆ octahedron in which _six oxygen atoms are coordinated with tetravalent Sn in the crystal structure, and a light absorption band in the ultraviolet region. In the semiconductor metal oxide in which oxygen exists, one or two oxygen atoms are removed from the SnO ₆ octahedron existing on the surface or inside, and the SnO ₅ polyhedron in which oxygen atoms are pentacoordinated or SnO ₄ in which oxygen atoms are tetracoordinated. A tetrahedral structure is present on the surface or inside, the band cap of the semiconductor metal oxide is reduced, and the functional wavelength region is extended to a long wavelength region. Thus, it is possible to produce a tin-containing semiconductor metal oxide that can be suitably used for a catalyst, a solar cell, a light-emitting element, or a light-detecting element.

At this time, in order to remove oxygen atoms from the SnO ₆ octahedron existing on the surface or inside,
Various reduction treatments and sputtering techniques can be applied, but many other methods are also conceivable.

Furthermore, according to the method for producing a tin-containing semiconductor metal oxide of the invention of this application, a part or all of the metal element of the semiconductor metal oxide having a light absorption band in the ultraviolet region and containing no Sn is tetravalent. By substituting with Sn, SnO ₆ octahedron is formed on the surface or inside,
By removing one or two of the oxygen atoms, a five-coordinated SnO ₅ polyhedron or an oxygen four-coordinated SnO ₄ tetrahedral structure is present on the surface or inside, and the semiconductor metal oxide It is also possible to reduce the band gap and extend the functional wavelength region to a longer wavelength region. At this time, a semiconductor metal oxide that has a light absorption band in the ultraviolet region and does not contain Sn is titanium oxide. In some cases, the functional wavelength region can be successfully extended to the long wavelength region, and in particular, the power generation wavelength region of the titanium oxide solar cell currently under development can be greatly expanded to improve its power generation efficiency. It is. Similar effects can be expected not only for titanium oxide but also for oxides of Zr, V, Nb, Ta, In, and Zn.

In this case as well, in order to remove oxygen atoms from the SnO ₆ octahedron existing on the surface or inside, various reduction treatments and sputtering techniques can be applied, but many other methods are also conceivable. .

  Hereinafter, examples will be described with reference to the accompanying drawings, and the tin-containing semiconductor metal oxide and the manufacturing method thereof according to the invention of this application will be described in more detail. Of course, the present invention is not limited to the following examples, and it goes without saying that various modes are possible for details.

An application of rutile structure to titanium oxide will be described as an example. Tin oxide SnO ₂ is known to exist stably as a rutile structure, and the lattice constants thereof are a = 4.74Å and c = 3.19Å. On the other hand, the lattice constants of rutile-structured titanium oxide are a = 4.59Å and c = 2.96Å, which are close to the lattice constant of rutile-structured SnO ₂ . Therefore, a part of Ti on the surface is S
It is relatively easy to substitute with n to provide defects in the coordinated oxygen.

FIG. 1 shows a schematic diagram of the crystal structure of rutile titanium oxide. FIG. 2 shows the electronic structure of rutile-structured titanium oxide calculated by the first principle theory. Note that the solid line in FIG. 2 represents the O2p orbital component, the chain line represents the Ti3d component, and the dotted line represents all components. Titanium is surrounded by six oxygen atoms to form a TiO ₆ octahedron (1).
Most of the intrinsic electron wave function component on the top of the valence band (corresponding to the energy level of the dotted line ef of the graph) is the O2p orbital component, and most of the state at the bottom of the conduction band is the Ti3d orbital component. It is well known that there is a light absorption band in the ultraviolet region, and that the rutile titanium oxide has the characteristics of the parent semiconductor metal oxide in the tin-containing semiconductor metal oxide of the invention of this application. Understand.

FIG. 3 shows a schematic diagram of the crystal surface structure in the case of including a TiO ₄ tetrahedron (2) from which two oxygen atoms have been removed from each of the TiO ₆ octahedrons (1) on the (001) surface of this titanium oxide. Shows the electronic structure of a material obtained by removing two oxygen atoms from each of the TiO ₆ octahedrons (1) on the (001) surface of titanium oxide. From FIG. 2 and FIG. 4, the band gaps are 2.7 eV and 2.6 eV, and there is no significant difference (in this example, the difference is only 0.1 eV). Even if oxygen is removed from the TiO ₆ octahedron, the band gap It can be seen that it cannot be effectively reduced. It becomes clear here that the change in the coordination number of the oxygen element with respect to titanium does not significantly affect the band gap, but this generally reduces the coordination number of the oxygen with respect to the oxygen 6-coordinated transition metal. However, it is difficult to reduce the band gap too much. However, the situation changes completely when a part of the titanium of the titanium oxide is replaced with Sn and oxygen in the SnO ₆ octahedron on the surface is extracted.

In FIG. 5, half of titanium of titanium oxide is replaced with tin to form SnTiO ₄ , and its surface Sn
The electronic structure is shown when two oxygen atoms are removed from the O ₆ octahedron. Its band gap is about 1.
The difference from the band gap of titanium oxide is about 1 eV. The theoretical calculated value of the band gap of the tin oxide SnO ₂ single crystal is 2.5 eV, which is almost the same as that of titanium oxide, but when two oxygen atoms of the SnO ₆ octahedron on the surface of the tin oxide SnO ₂ are extracted in the same manner. The band gap is about 1.6 eV. From these examples, it can be seen that the band gap of the base semiconductor metal oxide can be reduced by the invention of this application.

From the above, the surface or the inside of the semiconductor metal oxide containing SnO ₆ octahedron in which _six oxygens are coordinated to tetravalent Sn and having a light absorption band in the ultraviolet region is included in the crystal structure. It can be seen that the band gap can be reduced by removing one or two oxygen atoms from the SnO ₆ octahedron existing in the substrate.

  As described in detail above, the invention of this application is made of a semiconductor metal oxide that tends to be limited to the ultraviolet region by controlling the band gap by controlling the coordination number of oxygen element to tetravalent Sn. The functional wavelength region of the photocatalyst, the solar cell element, the light emitting element, and the light detecting element is extended to a longer wavelength side, for example, a visible light region. According to the present invention, when using solar energy, it is possible to further expand the wavelength sensitivity region. Therefore, development of highly efficient generation technology of hydrogen and oxygen from water by a photocatalyst, and high efficiency It is thought that it can greatly contribute to the development of solar power generation equipment. Perhaps the greatest point of the invention of this application is that it can provide a highly practical photocatalytic function, solar power generation function, light emitting function, photodetection function, etc. to many metal oxides that have not been noticed so far. It is. Since it is a basic invention that can be applied relatively easily, its significance is significant.

It is the schematic diagram which illustrated one Embodiment of the base | substrate semiconductor metal oxide of the tin containing semiconductor metal oxide of invention of this application. It is a graph of the electronic structure of one Embodiment of the base | substrate semiconductor metal oxide of the tin containing semiconductor metal oxide of invention of this application. It is the schematic diagram which illustrated the semiconductor metal oxide at the time of removing oxygen from the surface of one Embodiment of the base | substrate semiconductor metal oxide of the tin containing semiconductor metal oxide of this invention. It is a graph of the electronic structure of the semiconductor metal oxide when oxygen is removed from the surface of one embodiment of the parent semiconductor metal oxide of the tin-containing semiconductor metal oxide of the invention of this application. It is a graph of the electronic structure of one Embodiment of the tin containing semiconductor metal oxide of invention of this application.

Explanation of symbols

1 TiO ₆ octahedron 2 TiO ₄ tetrahedron

Claims (15)

Include SnO ₆ octahedra oxygen six tetravalent Sn in the crystal structure is coordinated, and a semiconductor metal oxide present light absorption band in the ultraviolet region, from SnO ₆ octahedra present inside or on the surface One or two oxygen atoms are removed, and a SnO ₅ polyhedron in which oxygen atoms are pentacoordinated or a SnO ₄ tetrahedral structure in which oxygen atoms are tetracoordinated is present on the surface or inside, and the semiconductor metal oxide A tin-containing semiconductor metal oxide having a small band gap and a functional wavelength region extended to a long wavelength region as compared with a product.   The tin-containing semiconductor metal oxide according to claim 1, wherein the tin-containing semiconductor metal oxide is used in any one of a photocatalyst, a solar cell, a light emitting element, and a light detecting element.   3. The tin-containing semiconductor metal oxide according to claim 1, wherein a promoter or an electrode is supported.   4. The tin-containing semiconductor metal oxide according to claim 3, wherein the promoter or the electrode is any one of a noble metal, a transition metal and an oxide. The tin-containing semiconductor metal oxide according to claim 4, wherein the promoter or the electrode is any one of Pt, Ni, IrO ₂ , NiO _x and RuO ₂ .   6. The tin-containing semiconductor metal oxide according to claim 1, wherein the tin-containing semiconductor metal oxide is used as a photocatalyst for oxygen production or a photocatalyst for hydrogen production.   6. The tin-containing semiconductor metal oxide according to claim 1, which is used as a photocatalyst for water splitting.   6. The tin-containing semiconductor metal oxide according to claim 1, which is used as a photocatalyst for decomposing chemical substances or a photocatalyst for producing chemical substances.   6. The tin-containing semiconductor metal oxide according to claim 1, wherein the tin-containing semiconductor metal oxide is used as a solar cell element used in a power storage device or a power generation device.   6. The tin-containing semiconductor metal oxide according to claim 1, wherein the tin-containing semiconductor metal oxide is used as a light emitting element used in an image display device, a signal device or a communication device.   6. The tin-containing semiconductor metal oxide according to claim 1, wherein the tin-containing semiconductor metal oxide is used as a light detection element used in a light detection device. Include SnO ₆ octahedra oxygen six tetravalent Sn in the crystal structure is coordinated, and a semiconductor metal oxide present light absorption band in the ultraviolet region, from SnO ₆ octahedra present inside or on the surface One or two oxygen atoms are removed and a five-coordinate SnO ₅ polyhedron or a four-coordinate SnO ₄ tetrahedral structure is present on the surface or inside, compared to the semiconductor metal oxide. A method for producing a tin-containing semiconductor metal oxide, comprising reducing a band gap and extending a functional wavelength region to a long wavelength region. By replacing part or all of the metal element with tetravalent Sn in the semiconductor metal oxide having a light absorption band in the ultraviolet region and not containing Sn, a SnO ₆ octahedron is formed on the surface or inside, By removing one or two of the oxygen atoms in the SnO ₆ octahedron, an oxygen pentacoordinate SnO ₅ polyhedron or an oxygen tetracoordinate SnO ₄ tetrahedral structure is allowed to exist on the surface or inside. A method for producing a tin-containing semiconductor metal oxide.   The semiconductor metal oxide having a light absorption band in the ultraviolet region and not containing Sn is any one of titanium oxide, zirconium oxide, vanadium oxide, niobium oxide, tantalum oxide, indium oxide, and zinc oxide. The method for producing a tin-containing semiconductor metal oxide according to claim 13. A method for decomposing a hazardous chemical substance, comprising irradiating the hazardous chemical substance with light in the presence of the photocatalyst for decomposing a chemical substance according to claim 8.

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