JP2005158551A - El fiber and photocatalysis reaction container - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an EL fiber having functions of decomposing and sterilizing organic matters, bacteria or the like and a photocatalysis reaction container using such an EL fiber. <P>SOLUTION: The EL fiber has a function of emitting ultraviolet rays with a wavelength of 400 nm or less or visible light. The fiber comprises an internal electrode positioned at the center in a radius direction, an internal insulating layer formed around it, a light-emitting layer, an external electrode, and a protecting layer formed on an outermost surface in a cross-section structure, and emits light by impression of an alternate current electric field between the electrodes. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an EL fiber having a function of decomposing and sterilizing organic substances and bacteria, and a photocatalytic reaction vessel using such an EL fiber.

Due to environmental problems in recent years, photocatalytic materials that decompose and sterilize harmful substances, bacteria, viruses, and the like are attracting attention. A typical photocatalyst is TiO ₂ , but since this is a material that generally exhibits a photocatalytic function with ultraviolet light having a wavelength of 400 nm or less, it can hardly exhibit a catalytic effect with sunlight with a low ultraviolet content. .
A photocatalytic material that also works with visible light having a wavelength exceeding 400 nm has been developed. This is a crystal system in which N, S, Mn, Fe, Co, Zn, Cu, or the like is doped into anatase type TiO ₂ , which increases the absorption of visible light, but most materials are visible. Although the photocatalytic function is activated even with light, the performance is reduced to about 1/100 compared with the combination of ultraviolet rays and anatase TiO ₂ . Only exceptionally doped with elemental sulfur has been reported to have no significant performance degradation. (See Non-Patent Document 1)

  However, in any case, in order to make these photocatalysts act, it is necessary to use an external light source such as a mercury lamp separately, which obstructs the compactness of the reaction vessel and requires the use of mercury, which is a harmful substance. . Recently, a light emitting diode (LED) that emits ultraviolet rays is used as a light source instead of a mercury lamp.

On the other hand, a light emitting fiber called an EL fiber that emits light by electroluminescence is known. Figure 1 shows the conceptual structure. 1 is an internal electrode, 2 is an internal insulating layer, 3 is a light emitting layer, 4 is an external insulator, 5 is an external electrode, and 6 is a protective layer. The external insulator 4 may be unnecessary. By applying an alternating voltage between the two electrodes, electrons in a high energy state called hot electrons move through the insulator layer in the light emitting layer, and this is a semiconductor particle in the light emitting layer or a specific particle added to the semiconductor particle. Luminescence occurs when the ions are excited. It is called an EL fiber because it is a fiber that emits light by electroluminescence. In general, commercially available EL fibers are only green and blue visible light emitting fibers, and are used for various illuminations. (See Non-Patent Document 2)
2003 Electrochemical Fall Conference, Abstracts of the Lecture, Electrochemical Society, 322 pages Plastics, Rubber and Compositions Proposing and Applications 1998. Vol. 27, no. 3,160-165 pages

Since the photocatalytic reaction is a reaction that occurs only on the particle surface, it is necessary to uniformly irradiate the particle surface with ultraviolet rays. But,
(1) When the object is a gas, it is necessary to float TiO ₂ particles, which are photocatalysts, in the reaction vessel, so a special device is required. In the case of a liquid, it is necessary to disperse the liquid in the liquid.
(2) Since ultraviolet rays are easily absorbed in the atmosphere, it is necessary to bring the light source closer, and it is difficult to apply to large reaction vessels. In particular, when the object is a turbid liquid, there is a problem that the attenuation of ultraviolet rays is severe and the external light source method cannot be applied.
The present invention has been found that the above-mentioned EL fiber can be improved by an original idea to solve the above-mentioned problems, and to provide a function of decomposing and sterilizing organic substances and bacteria.

  The first aspect of the present invention is an EL fiber mainly having an ultraviolet light emission function, which is an EL fiber having an ultraviolet light or visible light emission function with a wavelength of 400 nm or less, and the cross-sectional structure of the fiber is located at the center in the radial direction. The EL fiber includes an internal electrode, an internal insulating layer formed around the internal electrode, a light emitting layer, an external electrode, and a protective layer formed on the outermost surface, and emits light when an alternating electric field is applied between the electrodes. This is comprised from what the fluorescent substance particle which comprises a light emitting layer light-emits an ultraviolet-ray. Bacteria and viruses may be directly decomposed and sterilized by ultraviolet rays. In particular, 254 nm ultraviolet rays are widely used as sterilization lamps because they directly destroy bacterial and viral DNA, and EL fibers that emit 254 nm ultraviolet rays are an alternative to direct sterilization lamps.

The second of the present invention is an EL fiber having an ultraviolet or visible light emitting function, and an EL fiber having an ultraviolet or visible light emitting function with a wavelength of 550 nm or less, and the cross-sectional structure of the fiber is at the center in the radial direction. Consists of an internal electrode, an internal insulating layer formed around it, a light emitting layer, an external electrode, a protective layer, and a particle layer or thin film having a photocatalytic function formed on the outermost surface, and an alternating electric field is applied between the electrodes. EL fiber that emits light. That is, the EL fiber and the photocatalyst are integrated.
This is a method in which visible light or ultraviolet light that is emitted is irradiated onto a photocatalyst to decompose and sterilize organic matter, bacteria, viruses, etc. by photocatalytic action, and has a wider application than the first invention that emits only ultraviolet light.
The present invention is also a photocatalytic reaction vessel using the EL fiber, and further a photocatalytic reaction vessel having a structure in which EL fibers and photocatalytic fibers are alternately combined.

FIG. 1 shows an EL fiber to which the present invention is applied. One internal electrode may be an ordinary metal, and a copper wire is used. The internal insulating layer 2 is for applying an alternating electric field uniformly to the light emitting layer 3, and usually a dielectric resin such as cyanoresin is used alone, or a dielectric resin and a high dielectric constant such as BaTiO ₃ are used. A mixture of ceramic powders is used. The thickness is several tens of μm. Since the external electrode 5 must transmit ultraviolet rays or visible rays radiated from the light emitting layer 3, a transparent conductive film such as an indium-tin oxide (ITO) is used, or a NiCr alloy or the like is used. Candidates are thinned to 1 μm or less.

Reference numeral 6 denotes a protective layer for protecting the light emitting layer 3 and the external electrode 5 from external environmental factors such as moisture, and the light emitted from the inside must pass therethrough. When the light is visible light, a normal transparent resin may be used. However, when the light is ultraviolet light, it is necessary to use a resin excellent in ultraviolet light transmission. For example, there is acrylite manufactured by Mitsubishi Rayon. Further, the protective layer 6 itself may be a material having a photocatalytic function. For example, it is possible to coat dense TiO ₂ by sputtering.

The light emitting layer 3 is made of a normal EL fiber in which phosphor particles are dispersed in a dielectric resin and has a thickness of several tens of μm. Also in the present invention, a material that emits visible light having a wavelength exceeding 400 nm may be the same as a normal EL fiber. However, for shorter wavelengths, the use of a dielectric resin may degrade the resin due to long-term use, so it is preferable to use dielectric ceramics instead of the resin. As dielectric ceramics, various materials such as BaTiO ₃ , SrTiO ₃ , and PbTiO ₃ having a high dielectric constant are conceivable. That is, it becomes a kind of core-shell structure layer in which phosphor particles are dispersed in dielectric ceramics.

  The most important is the phosphor. As a phosphor material that emits light with high efficiency by electroluminescence in combination with a dielectric resin as in the present invention, a ZnS-based material is well known and is also used as a phosphor for general EL fibers. . (See Non-Patent Document 2)

As shown in FIG. 2, ZnS is doped with Cl or Al as the second additive element. These additive elements form a donor level under the conduction band of ZnS. On the other hand, Cu, Ag, or the like is doped as the first additive element. These elements form acceptor levels on the ZnS valence band. When energy such as an electron beam or ultraviolet light is irradiated into ZnS, electrons in the valence band are once excited to the conduction band and then trapped in the donor level. On the other hand, holes newly generated in the valence band are trapped in the acceptor level. Light emission occurs when electrons in the donor level recombine with holes in the acceptor level. This is a type of light emission called donor-acceptor (DA) light emission, which is a light emission mechanism that provides extremely high light emission efficiency. As shown in the equation (1), the emission wavelength is basically determined by the energy difference between the donor level and the acceptor level, and the larger this is, the shorter the wavelength is emitted. That is, the emission energy hν is
_{hν = Eg- (E D + E} A) -e 2 / (4πε 0 ε r r) (1)
Here, E _g is the band gap energy of ZnS, E _D is the donor of binding energy, EA is binding energy, e is elementary charge amount of the acceptor, epsilon ₀ is the vacuum dielectric constant, epsilon _r is the ratio electrostatic permittivity, r is the distance between the donor and the acceptor.

  Regarding ZnS-based phosphors having such a light emission mechanism, ZnS: Ag and Cl are practically used as blue phosphors, and ZnS: Cu and Al are practically used as green phosphors. Therefore, visible light having a wavelength of about 450 to 550 nm is used. In order to emit light, these phosphors may be used.

From equation (1), it can be seen that the emission wavelength is mainly determined by the band gap of the semiconductor material, the donor, and the acceptor level. That is, to the emission wavelength to the short wavelength, (1) the large _{E g,} (2) _E small _D, but it is necessary to reduce the (3) _{E A,} these, _{E D} is It does not change greatly depending on the element doped at about 0.1 eV. Also, E _A, so is 0.7eV with Ag doping, in order to shorten the wavelength of the emission wavelength is substantially it is most important to increase the E _g. Examples of additive elements that form acceptor levels include Cu, Ag, Au, Li, Na, N, As, P, and Sb. Examples of additive elements that form donor levels include Cl, Al, I, F, and Br.

There are mainly two methods for increasing the band gap energy (E _g ). One is to use a mixed crystal of ZnS and the second component semiconductor having a larger band gap than ZnS (E _g = 3.7 eV) as the base material semiconductor. As the second component semiconductor, there is the same II-VI compound semiconductor as ZnS, and it may be a selenide such as MgSe (E _g = 4.0 eV) or BeSe (E _g = 4.7 eV), but the same sulfide. It is easier to make a product by selecting the product. For example, MgS is preferable because Eg = 5.1 eV, CaS = 4.4 eV, and SrS = 4.3 eV. In addition, BaS and BeS are also candidates, but MgS is most preferable.

Another way to increase the bandgap is to reduce the size of the ZnS particles to nanosize. As the particle size decreases, the quantum size effect appears and the band gap increases. Of course, the particle size of the mixed crystal may be reduced. In this case, the particle size may be larger than that using ZnS alone. The particle size quantum size effect appears varies by E _g and E _A.

  With ZnS-20 mol% MgS, the emission wavelength is 400 nm or less regardless of the particle diameter. As described above, when the amount of MgS is large, there is a tendency that the restriction on the particle diameter is eliminated. However, when the amount of MgS is large, the light emission efficiency may be decreased. The same applies to other second component semiconductors. In that sense, the standard particle size is 10 nm or less.

In addition to these ZnS-based phosphors, materials that emit ultraviolet light include materials doped with Gd ions, such as Y ₂ O ₃ : Gd, Si—Y—O—N: Gd, and ZnF ₂ : Gd, and GaN, ZnO. Etc. are also candidates.

As the photocatalytic material, when using ultraviolet rays or visible rays having a wavelength of 400 nm or less, anatase, rutile, or broccite type TiO ₂ that is usually used may be used. For visible light exceeding 400 nm, TiO ₂ can be used as a visible light sensitive photocatalyst by doping at least one element of N, S, Mn, Fe, Co, Zn, and Cu. The most preferable is doped with S, which has the highest photocatalytic activity.

  The above-mentioned invention is a compact light source that directly emits ultraviolet light or can exhibit a photocatalytic function, so treatments such as fluids in narrow areas where external light sources do not reach and liquids with high turbidity By installing in the object, an efficient decomposition / sterilization apparatus can be achieved.

  The product of the present invention is a fiber that can emit ultraviolet rays by applying an alternating voltage or the like. By installing and operating the product of the present invention in a contaminated fluid, a photocatalytic reaction can be efficiently caused without using an external ultraviolet light source such as an ultraviolet lamp or an ultraviolet LED. In particular, a photocatalytic reaction can be efficiently caused even in the case of a polluted fluid that absorbs ultraviolet rays that cannot be processed by an external light source.

  The photocatalytic reaction vessel using the product of the present invention is capable of decomposing organic matter and sterilizing bacteria, etc., and therefore decomposing NOx, SOx, CO gas, diesel particulates, pollen, dust, mites, etc., which are pollutants in the atmosphere. Various removal and removal of organic compounds in sewage, sterilization light source for general bacteria and viruses, decomposition of harmful gases generated in chemical plants, decomposition of odorous components, sterilization light source in ultrapure water production equipment, etc. Applicable to fields.

  Moreover, it can also combine with a ceramic filter, a photocatalyst sheet, a photocatalyst woven fabric, etc. For example, by installing the product of the present invention in a cell of a ceramic honeycomb filter in which a photocatalyst is previously supported, it is possible to provide both functions of a ceramic filter separation function and a photocatalytic function. There is also a method of installing the product of the present invention so as to be knitted into a photocatalyst woven fabric. Thereby, it can be applied to a honeycomb material for automobile exhaust gas treatment, an air purifier filter, a sewage filter, various water purifiers, hot spring sterilizers and insect repellents.

  The present invention will be specifically described below with reference to examples.

A Cu wire having a diameter of 0.1 mm and a length of 1 m was used as a core electrode.
The following powder was prepared.
(Insulating layer formation)
BaTiO ₃ : Average particle diameter of 0.5 μm
Resin: manufactured by Shin-Etsu Chemical (trade name: Cyano Resin)
(Phosphor)
ZnS: Cu, Cl powder Average particle size 0.5 μm (commercially available)
ZnS: Ag, Cl powder Average particle size of 0.5 μm (commercially available)
ZnS: Ag, Cl powder Average particle size 3-15 nm
Commercially available ZnS: Ag, Cl powder (average particle size 0.5 μm) was obtained by pulverizing for various times at an acceleration of 150 G in Ar using a planetary ball mill apparatus (ball diameter is 50 μm).
(photocatalyst)
Anatase TiO ₂ average particle size 0.05μm (commercially available)
TiO ₂ : S Average particle size 0.05 μm
Thiourea (CH ₄ N ₂ S) powder and Ti (OC ₃ H ₇ ) ₄ were mixed in ethanol and concentrated under reduced pressure until a white slurry was formed. Then, it baked in the atmosphere at 600 degreeC for 2 hours, and obtained the powder. The doping amount of S was 2 at% with respect to oxygen.

(A) Formation of insulating layer The resin was dispersed and dissolved in cyclohexanone so as to be 30 vol%. A solution obtained by dispersing BaTiO ₃ powder (30 vol%) in this solution was applied to a Cu wire, controlled to a thickness of 30 μm with a rotating roller, and dried at 120 ° C. for 1 hr to form an insulating layer.
(B) Formation of light-emitting layer A resin was prepared by dispersing and dissolving resin in cyclohexanone so as to be 30 vol%. This solution was obtained by dispersing phosphor powder in Ar gas (30 vol%) on the surface of the insulating layer (a), controlling the thickness to 40 μm with a rotating roller, and drying at 120 ° C. for 10 hours to emit light. A layer was formed.
(C) Formation of external electrode It installed in the sputtering apparatus and the ITO electrode was coated by 0.2 micrometer at 130 degreeC on the light emitting layer surface.
(D) Formation of Protective Layer A melt of acrylite, which is an ultraviolet transmitting resin, was applied and coated with a rotating roller to a thickness of 100 μm.
(E) Formation of photocatalyst layer A liquid in which photocatalyst particles were dispersed in alcohol was prepared. After dipping this EL fiber, it was lifted to coat the surface of the EL fiber with TiO ₂ particles.

(F) Evaluation (1) Luminous efficiency An AC electric field of 150 V and 400 Hz was applied between the core electrode and the ITO electrode of the EL fiber before coating the photocatalyst layer. Luminance of luminescence was measured with a luminance meter or ultraviolet illuminance meter, and luminous efficiency was calculated from input power.
(2) Photocatalytic reaction experiment After bundled 500 pieces of 1 m long EL fibers coated with TiO ₂ , they were placed in a reaction vessel having a diameter of 50 cm and a length of 1 m. As shown in FIG. 3, water containing 100 ppm of trichlorethylene was introduced from one side of the container and circulated while being discharged from another outlet. In order to intentionally color the water, a 5% ink ink was added in advance to obtain a highly turbid liquid. At this time, an AC electric field of 150 V and 400 Hz was applied between all the core electrodes and the ITO electrodes. The time until trichloroethylene was completely decomposed was measured.

As a comparison, commercially available LEDs (light emission wavelength 360 nm, output 50 mW) arranged at intervals of 60 ° (FIG. 4) and mercury lamps (light emission wavelength 254 nm, output 100 mW) at 60 ° intervals, 90 mm. A sample arranged in pitch (FIG. 5) was prepared, and 100 g of the anatase TiO ₂ particles were dispersed in the liquid in the reaction vessel, and ultraviolet rays were irradiated from the outside of the vessel to measure the time until decomposition.

The results are shown in Table 1.

In the external light source method, the process was performed up to 100 hr, but trichlorethylene could not be completely decomposed. This is presumably because the photocatalyst does not function sufficiently because the transparency of the liquid is low and ultraviolet rays do not sufficiently penetrate into the container.
On the other hand, when the product of the present invention was used, decomposition occurred. Even visible light having a wavelength exceeding 400 nm can be decomposed by using TiO ₂ : S as a photocatalyst. Moreover, the decomposition ability was higher as ultraviolet rays were used and the ultraviolet wavelength was shorter. This is probably because the shorter the wavelength, the more the photocatalyst can be excited.

A Cu wire having a diameter of 0.1 mm and a length of 1 m was used as a core electrode.
The following powder was prepared.
(Insulating layer formation)
Ba (OCH ₃ ) ₂
Ti (OC ₂ H ₅ ) ₄
(Phosphor)
ZnS-MgS: Ag, Cl powder Average particle size 3-15 nm
Commercially available ZnS: Ag, Cl powder (average particle size 0.5 μm) and MgS powder (average particle size 0.5 μm) are mixed in a predetermined amount, and a planetary ball mill device (ball diameter is 40 μm) is used to accelerate acceleration in Ar. It was obtained by grinding with 144G for various times.

(A) Formation of insulating layer Each of the alcohol solutions of Ba (OCH ₃ ) ₂ and Ti (OC ₂ H ₅ ) ₄ was evaporated and introduced into a CVD reactor. On the other hand, oxygen was introduced from another system and reacted for 2 hours at a temperature of 900 ° C. and a pressure of 0.04 MPa, and the Cu core electrode surface was coated with BaTiO ₃ to a thickness of 20 μm.
(B) Formation of light-emitting layer In Ar gas, phosphor powder was dispersed in an alcohol solution (concentration 0.2 mol / l) mixed with equimolar amounts of Ba (OCH ₃ ) ₂ and Ti (OC ₂ H ₅ ) _4. The sample after the formation of the insulating layer was immersed in the solution and pulled up and baked at 900 ° C. for 30 minutes in the air. This was repeated 30 times to form a light emitting layer having a thickness of 20 μm in which phosphor particles were dispersed in BaTiO ₃ .

(C) Formation of external electrode It installed in the sputtering device and the ITO electrode was coated by 0.2 micrometer at 530 degreeC on the light emitting layer surface.
(D) Formation of protective layer also serving as photocatalyst TiO ₂ : S doped with 2 at% of anatase-type TiO ₂ or S with respect to oxygen at 600 ° C. was formed at a thickness of 5 μm by sputtering to form a protective layer.

(F) Evaluation (1) Luminous efficiency An AC electric field of 200 V and 300 Hz was applied between the core electrode of the EL fiber and the ITO electrode before coating the photocatalyst layer. Luminance of luminescence was measured with a luminance meter or ultraviolet illuminance meter, and luminous efficiency was calculated from input power.
(2) Photocatalytic reaction experiment After bundling 500 EL fibers having a length of 1 m, they were placed in a reaction vessel having a diameter of 50 cm and a length of 1 m. As shown in FIG. 2, water containing acetaldehyde having a concentration of 180 ppm was introduced from one side of the container and circulated while being discharged from another outlet. In order to color the water intentionally, the ink solution was added in advance with 10% of water to obtain a highly turbid liquid. At this time, an AC electric field of 200 V and 300 Hz was applied between all the core electrodes and the ITO electrodes. The time until acetaldehyde was completely decomposed was measured.

蛍光体をＺｎＳ−ＭｇＳ混晶系とすることにより、発光波長はより短くなり、分解速度も向上した。絶縁層や発光層中の誘電体を高誘電率のＢａＴｉＯ_３にすることにより、高い発光効率が得られた。
保護層としてＴｉＯ_２を用いても光触媒機能が発揮できた。 The results are shown in Table 2.

By making the phosphor a ZnS-MgS mixed crystal system, the emission wavelength was shortened and the decomposition rate was improved. High luminous efficiency was obtained by making the dielectric in the insulating layer and the light emitting layer BaTiO ₃ having a high dielectric constant.
Even when TiO ₂ was used as the protective layer, the photocatalytic function could be exhibited.

The EL fiber of Example 1 was made into a two-dimensional satin weave at a pitch of 3 mm to produce a woven fabric of 500 mm × 500 mm size. 6A is a plan view, and FIG. 6B is a cross-sectional view.
A woven fabric made of photocatalytic fibers (manufactured by Ube Industries) was cut into 500 mm × 500 mm.
50 layers of EL fiber woven fabric and photocatalyst woven fabric were alternately stacked to prepare a photocatalytic device.

This was placed in the container of FIG. 7 (a reaction container having a cross-sectional area of 500 mm × 500 mm and a thickness of 70 mm). 2,3 ′, 4,4 ′, 5-Pc-CB, which is a kind of dioxin, was dissolved in water to prepare 30 l of a solution having a concentration of 100 pg / l. At this time, in order to intentionally color the water, a liquid having a high concentration was prepared by adding 10% of ink in advance.
An AC electric field of 200 V and 500 Hz was applied between the electrodes while circulating this at a flow rate of 2.5 l / min. The time until dioxin was completely decomposed was measured up to 100 hr.

For comparison, a stack of 50 layers of only photocatalyst woven fabrics is placed in the same container, and commercially available LEDs (light emission wavelength 360 nm, output 50 mW) placed outside the container are arranged at a pitch of 35 mm (Fig. 9) and a mercury lamp (emission wavelength: 254 nm, output: 100 mW) arranged at a pitch of 35 mm (FIG. 8) were prepared, and the time until decomposition was measured by irradiation from the outside of the container.
The results are shown in Table 3.

  The product of the present invention has a shorter decomposition time than the external light source method. The difference was particularly large when a highly turbid liquid was processed. This is probably because the emitted light is absorbed by the pollution source in the external light source system. Even when the turbidity was low, the time until the product of the present invention was decomposed was short. This is considered to be because when the photocatalytic woven fabric is laminated, light does not reach the internal woven fabric uniformly in the external power supply system. On the other hand, in the product of the present invention, since the light source exists in the vicinity of the photocatalyst woven fabric, all the photocatalyst woven fabrics work uniformly regardless of the number of layers.

  The product of the present invention is a fiber that can emit ultraviolet rays by applying an alternating voltage or the like. By installing and operating the product of the present invention in a contaminated fluid, a photocatalytic reaction can be efficiently caused without using an external ultraviolet light source such as an ultraviolet lamp or an ultraviolet LED. In particular, a photocatalytic reaction can be efficiently caused even in the case of a polluted fluid that absorbs ultraviolet rays that cannot be processed by an external light source.

The conceptual diagram of EL fiber which can apply this invention is shown. It is explanatory drawing of the light emission mechanism of ZnS type fluorescent substance. It is explanatory drawing of a photocatalytic reaction test. It is explanatory drawing of the example which arranged LED which sells commercially available ultraviolet light at 60 degree intervals. It is explanatory drawing of the example which arranged the mercury lamp at intervals of 60 degrees. The top view (a) and sectional drawing (b) of the woven fabric produced with the EL fiber of Example 1 are shown. 10 is an explanatory diagram of Example 3. FIG. It is explanatory drawing of the comparative example with Example 3. FIG. Similarly, it is explanatory drawing of the other comparative example with Example 3. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Internal electrode 2 Internal insulating layer 3 Light emitting layer 4 External insulator 5 External electrode 6 Protective layer

Claims (14)

  An EL fiber with a UV or visible light emission function with a wavelength of 400 nm or less, and the cross-sectional structure of the fiber is an internal electrode located at the center in the radial direction, and an internal insulating layer, a light emitting layer, and an external layer formed around it. An EL fiber comprising an electrode and a protective layer formed on the outermost surface, and emits light when an alternating electric field is applied between the electrodes.   2. The EL fiber according to claim 1, wherein an external insulating layer is formed between the light emitting layer and the external electrode.   An EL fiber with a UV or visible light emission function with a wavelength of 550 nm or less, where the cross-sectional structure of the fiber is an internal electrode located at the center in the radial direction, and an internal insulating layer, a light emitting layer, and an external layer formed around it. An EL fiber comprising an electrode, a protective layer, and a particle layer or thin film of a material having a photocatalytic function formed on the outermost surface, and emits light when an alternating electric field is applied between the electrodes.   The EL fiber according to claim 3, wherein an external insulating layer is formed between the light emitting layer and the external electrode.   The EL fiber according to claim 3 or 4, wherein the protective layer itself is a material having a photocatalytic function. The material having a photocatalytic function is obtained by doping TiO ₂ and / or TiO ₂ with at least one element of N, S, Mn, Fe, Co, Zn, and Cu. EL fiber described in 1.   The EL according to any one of claims 1 to 4, wherein the light-emitting layer has a structure in which phosphor particles having a visible light or ultraviolet light emission function are dispersed in a matrix containing at least one of a dielectric resin or a dielectric ceramic. Fiber.   The first additive element in which the phosphor constituting the light emitting layer has an acceptor level in a semiconductor containing ZnS as a first main component and partly or not including a II-VI group compound semiconductor as a second component The EL fiber according to claim 1, further comprising a second additive element that forms a donor level.   9. The first additive element is at least one of Cu, Ag, Au, Li, Na, N, As, P, and Sb, and the second additive element is at least one of Cl, Al, I, F, and Br. EL fiber as described.   The EL fiber according to claim 8, wherein the first additive element is Ag.   The EL fiber according to claim 8, wherein the second component semiconductor contains at least one of MgS, CaS, SrS, BeS, and BaS.   The EL fiber according to any one of claims 1 to 4, wherein an average particle diameter of the phosphor constituting the light emitting layer is 10 nm or less.   A photocatalytic reaction vessel using the EL fiber according to any one of claims 1 to 4. A photocatalytic reaction vessel having a structure in which the EL fiber according to any one of claims 1 to 4 and the photocatalytic fiber are alternately combined.

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