JP2003053195A - Photocatalyst device consisting of sheet light emitting element as light source - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flexible photocatalyst device which is made smaller in thickness and lighter in weight as compared with the conventional photocatalyst device and widens the selection of a place for installation. SOLUTION: The photocatalyst having a photocatalyst function is used for UV rays or visible light, such as blue light and green light as well and an organic EL light emitting element or inorganic EL light emitting element to emit the visible light, such as the blue light or green light or the extremely thin sheet light emitting element which has the element structure resembling the organic EL element and of which the light emitting layer is polysilane or the like and which emits near UV and UV wavelength bands is utilized as the light source of the photoconductive device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electroluminescent device electroluminescence which is capable of emitting light in an ultra-thin and large area.
ence (hereinafter abbreviated as EL), a light emitting layer that emits light in the near-ultraviolet / ultraviolet wavelength band, such as polysilane, which is also capable of ultra-thin large-area light emission (here, one that emits ultraviolet light is also treated as one of the light-emitting elements) The present invention relates to a thin and light photocatalytic device using, as a light source, titanium oxide or the like having a photocatalytic function even with ultraviolet rays or visible light such as blue light and green light.

[0002]

_2. Description of the Related Art Titanium oxide, which is a substance represented by TiO ₂ , is an n-type semiconductor in which oxygen is deficient with respect to titanium. The band gap of titanium oxide is anatase type.
It is 2 eV and corresponds in energy to ultraviolet light of about 380 nm. When energy higher than the band gap is applied to titanium oxide, that is, when ultraviolet light shorter than 380 nm is irradiated, electrons in the valence band of titanium oxide are excited to the conduction band, and electrons and holes are generated inside titanium oxide. Is generated. This diffuses on the surface of titanium oxide and reacts with water and oxygen existing on the surface of the particles, resulting in ・ OH and ・ HO ₂
Is generated to oxidize and decompose organic substances. The photocatalytic reaction mechanism of these titanium oxides is shown below. TiO ₂ + h _ν → h ⁺ + e ⁻ h ⁺ + H ₂ O → H ⁺ + · OH (oxidation) e ⁻ + O ₂ + H ⁺ → · HO ₂ (oxidation) Titanium oxide The greatest feature of this photocatalytic action is titanium oxide. Does not change, and as long as clean energy such as light, water and oxygen is supplied, the oxidative decomposition action is permanently exhibited. However, light (ultraviolet rays) is required for the manifestation of the photocatalytic reaction in order to fully exert its function, and the photocatalytic reaction occurs only on the surface of the titanium oxide particles, so contact with the decomposition target is required. . In addition, although the target organic substance has no selectivity, a high-concentration target substance may have difficulty in exerting its function. TiO as a photocatalytic substance
₂ , oxide particles of V ₂ O ₅ , ZnO, WO _3, etc.
Irradiation with light including ultraviolet rays having a wavelength of 10 nm or less decomposes the organic substance, and TiO ₂ particles having anatase type crystal structure are particularly excellent in such a photocatalytic function. Deodorization and sterilization using a photocatalyst have been variously studied and some have been put to practical use. For example, WO94 / 11092 discloses an air treatment method using a photocatalyst under room lighting. Further, JP-A-7-102678 discloses a method for preventing nosocomial infections using a photocatalyst. Further, a method of removing nitrogen oxides contained in air using a photocatalyst is also known (for example, JP-A-7-331120).
JP-A-8-10576 and JP-A-8-99020.
issue). Further, a water purifying device using a photocatalyst has also been proposed (for example, Japanese Patent Laid-Open No. 8-47687). It is also used for decomposing atmospheric pollutants such as dioxins in exhaust gas using photocatalysts (Nikkan Kogyo Shimbun Co., Ltd., Industrial Materials Frontier of Industrial Materials, July issue, 69-71p.
(2001)) However, in each method, a photocatalyst such as titanium oxide which requires ultraviolet rays of 410 nm or less as excitation light is used. However, in addition to ultraviolet rays, visible light having a wavelength longer than ultraviolet rays and the like are also included in sunlight and artificial light that serve as excitation light sources. However, visible light is not used in ordinary photocatalysts such as titanium oxide,
It was very inefficient in terms of energy conversion efficiency. Here, in order to improve energy conversion efficiency, a titanium oxide photocatalyst having a photocatalytic function that is useful even in visible light such as blue light and green light has been developed. (JP-A-200
0-157841 or Nikkan Kogyo Shimbun, Industrial Materials Frontier of Technical Materials for Titanium Dioxide Photocatalyst July issue, 42-44p
(2001)). However, in any case, when sunlight or the like cannot be used, an ultraviolet lamp, a visible light lamp, or an LED using a cylindrical glass tube that requires a relatively large space and is heavy must be used as a light source. There wasn't.

[0003]

However, this has the following drawbacks. (B) If sunlight is not used, it is necessary to use an ultraviolet lamp, a visible light lamp, or an LED that uses a heavy columnar glass tube as a light source of the photocatalyst device. However, there is a limit in reducing the thickness and weight of the photocatalyst device due to the shape. The present invention has been made to eliminate these drawbacks.

[0004]

[Means for Solving the Problems] An organic EL light-emitting element that emits visible light such as blue or green, an inorganic EL light-emitting element, or an element structure similar to an organic EL element is used, and the light-emitting layer is polysilane or the like and near-ultraviolet / ultraviolet light is used. A light emitting element that emits a wavelength band can emit ultra-thin large-area light, and by using these light emitting elements as a light source, it has become possible to reduce the thickness and weight of the photocatalytic device. The present invention is a photocatalyst device having the above-mentioned configuration, which is aimed at ultra-thin weight reduction.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. (B) When an organic EL light emitting element is used as a light source, a practical blue light emitting element or green light emitting element has already been developed and applied to a display or the like, and therefore, this may be used as a light source of a photocatalytic device. An organic EL light-emitting device has a structure in which a thin film containing a fluorescent organic compound is sandwiched between a cathode and an anode, and electrons and holes are injected into the thin film to recombine to generate excitons (exciton). ) Is generated and light is emitted by utilizing the emission of light (fluorescence / phosphorescence) when the exciton is deactivated. The characteristic of this organic EL element is 100 to 10000 at a low voltage of 10 V or less.
It is possible to perform surface emission with high brightness of about 0 cd / m ^{2 and} to emit light from blue to red by selecting the type of fluorescent substance. Further, the light emitting layer itself can be 1 μm or less, and the total thickness including the transparent substrate can be 2 mm or less. Here, a flexible organic EL light-emitting device can be manufactured without fear of being rolled and broken like paper (for example, Japanese Patent Laid-Open No. 2000-268954; JP 2000
-260560 Nihon Keizai Shimbun, June 22, 2001, etc.). A method for forming a film of an organic EL light emitting element uses a vacuum deposition method (for example, as a manufacturing method using a vacuum deposition method for a blue light emitting organic EL element, there are JP-A-5-17765 and JP-A-9-53068). A method using a spin coating method (for example, as a manufacturing method using a spin coating method for a blue light emitting organic EL device, JP-A-9-111233,
There is JP-A-10-324870. ), And a method of applying organic EL to the original plate corresponding to the stamp by applying printing technology and bringing the original plate and the substrate into close contact with each other (Nikkei Sangyo Shimbun, 2
(May 17, 001, etc.) and those using the inkjet method (Japanese Patent Laid-Open No. 10-153967, etc.) and others such as casting method, dipping method, bar coating method,
There is a roll coat method. In particular, the manufacturing method using the spin coating method is suitable for the light source of the present photocatalytic device, which requires uniform and large-area monochromatic light emission. In addition to the published patents exemplified here, high-efficiency blue light-emitting or high-efficiency green light-emitting organic EL elements have been developed, and thus they may be used as the light source. (B) In the case where a light emitting element whose light emitting layer emits near-ultraviolet / ultraviolet wavelength band is used as a light source, in a light emitting element including at least a hole injecting electrode, an electron injecting electrode, and a light emitting layer formed between these electrodes. The light emitting layer is formed of polysilane. Further, the light emitting layer further has the following general formula (Formula 1):

[Chemical 1] (In the formula, n is an integer of 1 or more, and R1 and R2 are independently an alkyl group, an aryl group, a cycloalkyl group,
Or a substituted aryl group). The manufacturing method is almost the same as that of the organic EL element (for example, JP-A-9-2
Therefore, the total thickness can be 2 mm or less including the transparent substrate. Here, if a transparent substrate is formed of a special plastic film that does not easily transmit moisture or gas, it is possible to fabricate a flexible near-ultraviolet / ultraviolet wavelength band-emitting element that does not have the risk of being rolled and broken like paper. 4 by changing R ₁ , R ₂ etc.
It can emit near-ultraviolet / ultraviolet wavelength band of 15 to 335 nm, and when used as a light source of photocatalyst, it has been used conventionally without using special titanium oxide having a photocatalytic function even in visible light. Inexpensive titanium oxide for photocatalyst can be used. Of course, if the light emitting layer is other than polysilane as long as it can emit near-ultraviolet / ultraviolet wavelength band, that may be used. (C) When an inorganic EL light emitting element is used as a light source, the basic configuration is a light emitting element in which a hole injection electrode, an insulating layer, an inorganic EL light emitting layer, an insulating layer, and an electron injection electrode are laminated. The electrons injected from the interface between the insulating layer and the light emitting layer into the light emitting layer are accelerated in the light emitting layer by the high electric field and collide with the emission center. At this time, the emission center is excited and emits light. For example, in the case of obtaining blue light emission, the light emitting layer is ZnS to which Tm (thulium) is added. To obtain green light emission, there is ZnS to which Tb (terbium) is added. Recently, SrS containing copper in strontium sulfide as a blue light emitting material:
Improvement of properties was reported with Cu (Nikkan Kogyo Shimbun, TR
IGGER, March issue, 21-23p (1999)).
As a specific method for producing a blue light-emitting inorganic EL device, Japanese Patent Application Laid-Open No. 2-212058
000-104059 and Japanese Patent Application Laid-Open No. 2000-104060. The total thickness of the inorganic EL element including the transparent substrate can be 2 mm or less. The inorganic EL element is inferior to the organic EL element in terms of luminous efficiency particularly in terms of blue and green light emission, but has an ability exceeding that of the organic EL element in terms of luminous lifetime and heat resistance. Of course, depending on the progress of research in the future, organic EL may be used in terms of luminous efficiency.
There is a possibility of exceeding the number of elements, and in that case, that may be used as the light source of the photocatalyst. (D) As a method of supporting a photocatalyst such as titanium oxide on a substrate, the following methods are generally performed according to the form. When powder is used, it is dispersed and fixed on an inorganic base material. Alternatively, the powder is mixed with pulp and papermaking is performed. When using a sol, for example, in the case of titanium oxide, it is a sol in which all anatase type titanium oxide particles are peptized / suspended, and since the sol itself has no film-forming property, it is directly applied to a porous substrate and baked. Or by mixing and coating with an inorganic resin, titanium oxide or the like is uniformly immobilized on the substrate. When using a slurry, the powder is dispersed in a desired medium. It is characterized by undergoing a very powerful dispersion process. The method of use is the same as for sol. When a coating agent is used, since it has almost a film-forming property and the film is transparent, titanium oxide or the like can be fixed only by coating without impairing the design of the base. When the base material is an inorganic material such as glass or metal, the photocatalyst coating agent can be directly applied since the base material is not deteriorated by the photocatalyst. Further, in the case of a base material having heat resistance, firing is possible. When the base material is an organic material, the base material itself is deteriorated by a photocatalyst, and thus an undercoat is necessary.
Basically, since an organic material has no heat resistance and cannot be fired, a room temperature curing type coating agent is suitable. Generally, the film hardness is stronger when baked than when it is cured at room temperature. An inorganic coating agent is desirable as the undercoat. Examples of the coating method include a spray coating method, a dip coating method, a spin coating method and a brush coating method. Specifically, as a supporting method on glass or the like, JP-A-10-53439 and JP-A-10-53439 are used.
231146 and the like are shown. Japanese Patent Application Laid-Open No. 10-16121 and the like are disclosed as a method for supporting an organic polymer. Further, Japanese Patent Laid-Open No. 9-310039 discloses a method for supporting any complicated shape such as an organic polymer, glass or metal film, plate, tube, fiber or net. Further, Japanese Patent Laid-Open No. 10-128125 and the like are shown as a method of carrying the paper. The supporting base material and supporting method are not limited to the above-mentioned methods. In addition, a thin film of titanium oxide or the like can be formed on a large area of glass by using a semiconductor thin film manufacturing apparatus called "sputtering" as a supporting method for glass (the Nikkan Kogyo Shimbun Co., Ltd., industrial materials, practical technology of titanium oxide photocatalyst). Front issue July issue, 49-53p (2001) or Mainichi Shimbun Monday, July 2, 2001). The sputter method is a method of forming a thin film of titanium oxide on the surface of a material by irradiating ions in a vacuum device. The titanium oxide thin film made by this method had no photocatalytic function until now, but by lowering the voltage of ion irradiation, increasing the strength of the magnetic field, and further injecting gas into the vacuum device, thin film formation and photocatalysis It is possible to achieve both activities. It is possible to form even a glass of several meters square. It has high adhesion to the glass surface, so it has high durability. Using the above method, (a),
(B), (c) Light-emitting element Transparent substrate surface and reflector plate or other substrate on which the photocatalyst is to be supported carries a photocatalytic substance such as titanium oxide, which has photocatalytic ability for ultraviolet light or visible light such as blue light or green light. Let (E) Assemble the photocatalyst device. (A), (b),
A photocatalyst such as titanium oxide is supported on either or both of the transparent substrate surface and the reflector surface of the light emitting device of (C). Then, the transparent substrate surface of the light emitting element and the reflecting surface of the reflecting plate are opposed to each other (FIG. 4). The base material is not particularly limited as long as the reflection plate can carry the photocatalyst, but in order to efficiently irradiate the photocatalyst with ultraviolet rays or light, the reflection plate is preferably a base material having a mirror surface. Block the surroundings, except for the inlet and outlet of the gas or liquid that you want to treat with a photocatalyst. It is desirable that the base material that closes the periphery is a light emitting element carrying a photocatalyst or a base material having a mirror-like surface (FIG. 1). Further, a spacer may be inserted between the surface of the light emitting element and the reflecting plate on the opposite side so as not to come into contact with each other, or a protrusion as a spacer may be formed in advance on the surface of the light emitting element substrate or the surface of the reflecting plate. Further, it is desirable to support the photocatalyst on the spacer itself in order to improve the photocatalytic treatment capacity. Further, in order to improve the processing capacity of the photocatalyst, the light emitting surface of the light emitting element carrying the photocatalyst may be opposed to each other without using a reflector so that the photocatalyst can be irradiated with light more efficiently (FIG. 3). ). Furthermore, a single layer or a plurality of layers of the photocatalyst-supported substrate may be inserted between the light emitting elements and the reflectors facing each other or between the light emitting elements facing each other (FIG. 5) (FIG. 6). Further, in order to increase the exposed area of the photocatalyst per unit space, the surface of the light emitting device or the surface of the reflector or the surface of the base material inserted therebetween may be roughened (FIG. 7) (FIG. 8). The material of the substrate to be inserted is not limited as long as it can support the photocatalyst without deterioration, but it is desirable that the surface of the substrate has fine irregularities, or fibrous or net-like one, because the exposed area of the photocatalyst increases. However, when a reflecting plate is used, if the substrate to be inserted is opaque, ultraviolet rays and light from the light emitting element cannot reach the reflecting plate. In this case, therefore, a transparent substrate such as glass or plastic is preferable. Similarly, in the case where the inserted substrate has a plurality of layers, if the substrate is opaque, ultraviolet rays or visible light does not reach between the substrates, so that the substrate is preferably transparent. In addition, if you want to process a large amount of gas or liquid in a short time, you can use the above-mentioned structure in which the light emitting element and the reflector or the light emitting element face each other.
As one unit, stacking multiple layers of this unit enables mass processing (Fig. 9). Since the light-emitting elements originally taken up in (a), (b), and (c) have an extremely thin cross section as compared with ordinary ultraviolet lamps and visible light lamps, one unit itself is thin. Therefore, even if a plurality of layers are stacked, the overall thickness does not become so thick. Here, if a transparent plastic of the light emitting element carrying the photocatalyst is made of a special plastic film that does not easily permeate moisture or gas, it is possible to make a flexible light emitting element that is not rolled and cracked like paper, as described above. The organic EL element is actually manufactured. Similarly, if a flexible base material such as plastic, metal, or fibrous base material is used for other photocatalyst-supporting base materials, there is no risk of rolling and breaking like paper, as a whole. It is possible to manufacture a flexible photocatalytic device that does not have a flexible structure. As described above, the organic base material needs an undercoat so that the base material itself is not deteriorated by the photocatalyst. If this is used, the photocatalyst device can be deformed according to the shape of the installation place, and the installation becomes easy. Here, since the light emitting element faces the inside of the device, it is unknown from the outside whether the light emitting element is emitting light properly or whether the light emitting element has reached the end of its life and not emitting light. In addition, it is not known from the beginning that an element such as polysilane that emits ultraviolet rays emits ultraviolet rays. Therefore, a transparent window is provided in a part of the photocatalyst device so that the inside can be seen so that the light emission state inside can be visually recognized from the outside. Alternatively, a fluorescent material is applied to the transparent window portion, and the ultraviolet rays generated therein are irradiated to emit light, so that whether the ultraviolet rays are emitted or not can be visually recognized from the outside. The present invention has the above structure,
It is used as a photocatalytic device for deodorization of the atmosphere, sterilization, or sterilization of water.

[0006]

This has the following effects. (A) The light source used in this photocatalyst device can emit ultra-thin large-area light, and thus the photocatalyst device itself can be made thin and lightweight. Therefore, the present photocatalyst device takes up less space than conventional photocatalyst devices, can be installed anywhere, and is easy to carry and install. (B) In a light emitting element whose organic EL light emitting element or a light emitting layer having a similar element structure emits near-ultraviolet / ultraviolet wavelength bands such as polysilane, paper is used if a special plastic film or the like that does not easily transmit moisture or gas is used for the transparent substrate. It is possible to fabricate a flexible photocatalyst device that does not have to be rolled and cracked as described above. (C) In this photocatalyst device, the life of the light emitting element can be seen at a glance by visually recognizing the light emission state from the detection window, so that it is easy to know the replacement time. The present invention brings about these effects. The embodiments are not limited to the examples of the present specification and other specific shapes as long as they are in accordance with the idea of the invention according to the present application.

[Brief description of drawings]

FIG. 1 is a perspective view of a basic structure of the present invention.

FIG. 2 is a cross-sectional view of the processing gas or processing liquid of the present invention as seen from the inlet side.

FIG. 3 is a cross-sectional view seen from the side when the light emitting elements are faced to each other in the present invention.

FIG. 4 is a cross-sectional view seen from the side when the light emitting device and the reflection plate are opposed to each other in the present invention.

FIG. 5 is a cross-sectional view seen from the side when the light emitting elements are faced to each other and the base material carrying the photocatalyst is inserted therebetween in the present invention.

FIG. 6 is a cross-sectional view seen from the side when a light-emitting element and a reflection plate are faced to each other and a base material carrying a photocatalyst is inserted therebetween in the present invention.

FIG. 7 is a cross-sectional view seen from the side when a light-emitting element having an uneven surface is faced to each other and a base material having an uneven surface is inserted to insert a base material carrying a photocatalyst in the present invention.

FIG. 8 is a cross-sectional view as seen from the side when a light emitting element having an uneven surface and a reflecting plate are faced to each other and a base material having an uneven surface is inserted and a substrate carrying a photocatalyst is inserted therebetween in the present invention.

FIG. 9 is a cross-sectional view seen from the side when a plurality of photocatalyst devices as shown in FIGS. 3, 4, 5, 6, 7, and 8 are stacked in the present invention to enhance the processing capacity. Is.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Photocatalyst 2 Spacer 3 A planar element that emits visible light or ultraviolet rays including a transparent substrate and part of which may be a reflector 4 Transparent substrate 5 A planar element 6 that emits visible light or ultraviolet rays 6 Reflector 7 Photocatalyst supporting substrate 8 Lifetime confirmation window for planar elements that emit visible light or ultraviolet rays

Claims (10)

[Claims] 1. A photocatalytic device using titanium oxide or the like, which uses an organic EL light emitting element or an inorganic EL light emitting element as a light source. 2. A photocatalyst device using titanium oxide or the like as a light source of a light emitting element that emits near-ultraviolet / ultraviolet wavelength bands such as polysilane in the light emitting layer. 3. An organic EL light emitting element, an inorganic EL light emitting element, or a light emitting layer of a light emitting element which emits near-ultraviolet / ultraviolet wavelength band such as polysilane and a reflecting surface of a reflecting plate face each other (FIG. 4). A photocatalytic device in which a photocatalyst such as titanium oxide is carried on one or both of the surfaces of the reflector. 4. An organic EL light emitting device, an inorganic EL light emitting device, or a light emitting device in which a light emitting layer emits near-ultraviolet / ultraviolet wavelength bands such as polysilane. The light emitting surfaces of the two light emitting devices are opposed to each other (FIG. 3). A photocatalyst device in which a photocatalyst such as titanium oxide is carried on one or both sides. 5. A transparent glass or glass fiber carrying a photocatalyst such as titanium oxide between the light-emitting element and the reflecting plate facing each other in the photocatalyst having the structure according to claim 3 or 4, or between the light-emitting elements facing each other, or A photocatalyst device (Fig. 5) (Fig. 6) in which a single layer or a plurality of layers of resin or resin fiber carrying a photocatalyst undercoated so that a metal or an inorganic substance or a substrate itself is not deteriorated by the photocatalyst. 6. A photocatalyst device having a structure according to claim 1, claim 2, claim 3, claim 4, claim 5, wherein a plurality of such units are stacked to enhance the catalyst treatment capacity. Photocatalytic device (Fig. 9). 7. A photocatalyst device having a structure according to claim 1, claim 2, claim 3, claim 4, claim 5 or claim 6, which can be folded into a substrate of a light emitting element or a base material carrying a photocatalyst. A photocatalytic device that can be freely changed in shape according to the installation location or according to the preference of the installer by using flexible resin, glass, metal, or inorganic material. 8. A photocatalyst device having the structure according to claim 1, claim 2, claim 3, claim 4, claim 5, claim 6, and claim 7, wherein a base material is used for various base materials. A photocatalyst device (FIG. 7) (FIG. 8) in which the surface area density having a photocatalytic function is increased by roughening the surface and then carrying a photocatalyst to improve the photocatalytic treatment ability. 9. A photocatalytic device using an organic EL light emitting element, an inorganic EL light emitting element, or a titanium oxide as a light source of a light emitting element whose emission layer emits near-ultraviolet / ultraviolet wavelength bands such as polysilane. A photocatalyst device (8 in Fig. 1) that makes it possible to see at a glance that the life of the light-emitting element has been extended by making it visible from the outside or by taking out part of the near-ultraviolet / ultraviolet light and applying it to a phosphor. 10. A photocatalyst having a structure according to claim 1, claim 2, claim 3, claim 4, claim 5, claim 6, claim 7, or claim 8 carrying a photocatalyst such as titanium oxide. A photocatalytic device with spacers or a photocatalytic device with spacers that have a photocatalytic function so that the processed materials can pass through the gaps without the base materials touching each other.