JP2007234413A - Fiber-like light light-emitting body, its manufacturing method, and goods using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fiber-like light-emitting body superior in light-emitting performance and flexibility and its manufacturing method, and moreover, an article such as a display body or an illumination body which has been made as a new design body by using the fiber-like light-emitting body high in flexibility. <P>SOLUTION: This is the fiber-like light-emitting body which is provided with a fiber-like core material 2 composed of a conductive material, a light-emitting layer 3 installed at the outer periphery of the core material 2, a conductive layer 4 installed at the outer periphery of the light-emitting layer 3, and an insulating layer 5 installed at the outer periphery of the conductive layer 4, and in which light is emitted by applying a voltage between the core material 2 and the conductive layer 4. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fibrous light-emitting body that is applied to various uses such as a display, an illuminating body, and a light source for optical communication, and emits light upon application of a voltage, a manufacturing method thereof, and an article using the same.

  Recent advances in information technology and IT technology have greatly accelerated the development of light emitting elements such as luminescence elements and lasers. In each of these elements, it is important to efficiently emit light generated inside the element to the outside. For this reason, development of materials with high luminous efficiency, or research to emit light without loss of light (to increase light extraction efficiency) is underway. For example, to extract light generated inside the device to the outside A transparent electrode (an electrode having optical transparency) is disposed on the light extraction surface.

  The light-emitting element having the above configuration is applied to various displays, meters, signals, indicators, illumination bodies, light sources for optical communication, etc., and even if a single flat TV is taken up, a plasma display that benefits from high brightness and wide viewing angle, Various researches such as organic electroluminescence (EL) display and field emission display have been actively conducted. In addition to TV, it is used as a display for personal computers, various flat panel displays such as navigation for automobiles, or as mobile phones, electronic paper and mobile personal computers with the progress of mobile.

  The light-emitting element has a configuration in which an anode and a cathode are arranged in a sandwich shape with a light-emitting layer interposed therebetween. When this light-emitting element is mechanically viewed, the movement of charge carriers (electrons, holes) at the junction interface between the anode and the light-emitting layer and the junction interface between the cathode and the light-emitting layer is positively utilized. The optical function is expressed.

  As a typical example of a light emitting element, an organic electroluminescence (EL) element which has recently been attracting attention is given, and its configuration and operation will be described in more detail.

  An organic electroluminescence (EL) element has a transparent electrode (ITO: Indium Tin Oxide) disposed on a transparent substrate (glass, resin) as an anode, and a light emitting layer and an electrode (Mg. Ag) is arranged to form a multilayer laminated structure. Furthermore, a power source is connected between the anode and the cathode so that a voltage can be applied.

  In the organic electroluminescence device having the above-described configuration, holes are injected over the potential barrier height Δφ of the junction interface from the anode side toward the light emitting layer by the voltage applied between the anode and the cathode, Electrons are injected from the cathode side toward the light emitting layer over the potential barrier height Δφ at the junction interface, and the electrons and holes recombine to emit light. The light emitted from the recombination of electrons and holes is emitted from the transparent electrode (anode) side, thereby taking out light to the outside of the light emitting element.

For example, the magnitude of the ionization potential Φ _a of ITO, which is a transparent electrode (anode), is about 4.5 to 4.7 eV, whereas the magnitude of HOMO (Highest Occupied Molecular Orbital), which is the highest empty level of the light emitting layer. The height Φ _H is about 5.4 to 5.8 eV, and the height ΔΦ of the potential barrier at the junction interface between the anode and the light emitting layer is as very large as 0.7 eV to 1.3 eV. When the potential barrier is increased, holes are less likely to be injected from the anode side, and in order to obtain the target light emission luminance, it is necessary to increase the voltage applied between the anode and the cathode. It was supposed to prevent the low voltage drive of the EL element. Furthermore, it has become very difficult to secure an injection balance with electrons injected from the cathode, and it has been difficult to maintain stable light emission.

Therefore, a method is disclosed in which the anode (transparent electrode: ITO) is fixed and a buffer layer is inserted between the anode and the light emitting layer so that the height of the potential barrier between them is an intermediate level (non-patent). Reference 1). According to this method, by inserting a buffer layer and changing the energy difference between the anode and the light emitting layer in steps, holes (holes) can easily overcome the height ΔΦ of the potential barrier. It can be easily moved toward the light emitting layer. However, the minimum empty level (Lowest Unoccupied Molecular Orbital: LUMO) and the maximum empty level (HOMO) size Φ _L , Φ _H of the buffer layer cannot be controlled arbitrarily, and can be used for coating, curing, etc. There was a risk that the process would increase and the cost would increase.

  In addition to the ITO thin film described above, ATO (Antimon doped Tin Oxide), FTO (F doped Tin Oxide), ZnO (Zinc Oxide), etc. are known in consideration of the anode material, all of which are inorganic materials. It lacked flexibility. Furthermore, in the case of a cathode material, it is necessary to use an alloy (for example, Mg / Ag, Mg / In, Li / Al, etc.) or a metal material (for example, Al) having a relatively small work function. Lacked flexibility.

In the light-emitting element having the above structure, for example, a constituent material is formed on a glass or flexible resin substrate using a dry process (for example, vacuum deposition), and an electrode (for example, ITO as an anode) is formed and sequentially stacked on the electrode. Alternatively, water or a solvent-soluble material is printed directly on a glass or flexible resin substrate sequentially by wet processes (thin film formation methods such as spin coating and casting methods, and printing techniques such as inkjet methods). How to do is being studied.
"Story of organic EL", page 49, edited by Nikkan Kogyo Shimbun

  However, since the above-described light-emitting element has a multilayer structure in which electrodes and a light-emitting layer are sequentially laminated on a flat substrate such as glass or resin, it is difficult to form a fiber with excellent flexibility. Applications such as high-brightness and low-viewing-angle flat panel displays, or flexible displays that can be easily carried (rounded displays), wearable displays, flat or highly flexible lighting bodies, and high-intensity light sources for optical communications It was difficult to use.

  The present invention has been made to solve the above-described problems. That is, the fibrous light emitter of the present invention includes a fibrous core material made of a conductive material and a light emitting layer provided on the outer periphery of the core material. And a conductive layer provided on the outer periphery of the light emitting layer, and an insulating layer provided on the outer periphery of the conductive layer, and applying a voltage between the core material and the conductive layer to emit light. To do.

  In the method for producing a fibrous light emitter of the present invention, a conductive material for a core material is disposed at the center of a molding die, and a light emitting layer material, a conductive layer material, and an outer periphery of the conductive material for the core material are provided. Insulating layer material is layered in order, and each is arranged as a solution that is soluble in water or solvent, and while applying voltage to each solution, injection molding is performed at the same time to obtain a fibrous light emitter. Is the gist.

  According to the present invention, it is possible to obtain a fibrous luminous body excellent in luminous performance and flexibility. Therefore, it can also be used as a display body or illumination body of a novel design body that requires flexibility.

  Hereinafter, a fibrous light-emitting body, a manufacturing method thereof, and an article using the same according to an embodiment of the present invention will be described with reference to the accompanying drawings.

  FIG. 1A is a cross-sectional view of a fibrous light emitter 1 according to an embodiment of the present invention, and FIG. 1B is a cross-sectional view of a fibrous light emitter 7 having a rectangular cross-sectional shape. As shown in FIGS. 1 (a) and 1 (b), the fibrous light emitters 1 and 7 are provided with fibrous core materials 2 and 8 made of a conductive material. On the outer periphery, the light emitting layers 3 and 9, the conductive layers 4 and 10, and the insulating layers 5 and 11 are sequentially arranged concentrically. Furthermore, the power supply 6 and 12 is connected to the fibrous core materials 2 and 8 made of a conductive material and the conductive layers 4 and 10 to apply a voltage. As a result, the core materials 2 and 8 and the conductive layers 4 and 10 serve as electrodes, and light emission occurs from the light emitting layers 3 and 9 according to the magnitude of the applied voltage. The core materials 2 and 8 are not limited to conductive materials. As shown in the fibrous light-emitting body 13 of FIG. 2A, the core materials 2 and 8 are non-conductive using a non-conductive base material 14 as a core material. The first conductive layer 15, the light emitting layer 16, the second conductive layer 17, and the insulating layer 18 may be sequentially arranged on the outer periphery of the substrate 14 in a concentric circle shape. By adopting such a structure, the core material acts as a tensile body, and even when an external force is applied, bending or breaking can be avoided. In any case, the first conductive layer 15 disposed on the outer periphery of the core material functions as an anode or a cathode. Moreover, as shown in FIG.2 (b), you may comprise the fibrous light-emitting body 19 connected in a ring shape, and as shown in the expanded sectional view of the AA 'line of FIG.2 (c), The fibrous light emitter 19 is configured by sequentially arranging a light emitting layer 21, a conductive layer 22, and an insulating layer 23 in a concentric circle shape on the outer periphery of a core member 20 made of a conductive material. .

  It becomes possible to make it into a fiber shape by setting it as the said structure, and it becomes possible to set it as various knitted fabrics by weaving or knitting similarly to a normal fiber.

  In the present invention, the term “fibrous” does not mean a fiber (fiber) itself, but means that a fiber-like long structure is included. In the case of a long structure, the cross-sectional shape may be circular, elliptical, rectangular, flat, or polygonal, and the shape is not limited.

A state in which a voltage is applied to the fibrous light emitter 1 having the above configuration will be described with reference to FIG. As shown in FIG. 3, when a DC voltage is applied to both electrodes of the core material (the anode 24 in the figure) made of a conductive material and the conductive layer 4 (the cathode 25 in the figure), the anode 24 Holes 27 are injected into the light emitting layer 26 from the side exceeding the height of the potential barrier (Δφ _A ), and electrons 28 are injected into the light emitting layer 26 from the cathode 25 side beyond the height of the potential barrier (Δφ _B ). Is injected in a well-balanced manner. In the light emitting layer 26, the injected holes 27 and electrons 28 are recombined to generate light of a specific wavelength.

Here, the conductive layer (cathode 25) and the insulating layer are preferably configured to have light transmittance in the visible light region (wavelength 380 nm to wavelength 780 nm), whereby light generated in the light emitting layer 26 is transmitted through the light. It is possible to efficiently emit light to the outside from the conductive layer 26 and the insulating layer. This is because in the fibrous light emitter in FIG. 3 (a), the light generated in the light emitting layer 26 is emitted to the outside of the fibrous light emitter so that the conductive layer (cathode 25) surrounding the outer periphery of the fibrous light emitter. This is because light needs to be emitted from the insulating layer, and from this point of view, both layers need to be light transmissive. In this respect, it was found that the generated light can be extracted to the outside from a practical viewpoint by satisfying the following relationship. That is, if the total light transmittance in the visible light region of the conductive layer (cathode 25) is T _b , the total light transmittance in the visible light region of the insulating layer is T _i , and the product of the total light transmittance of both is T. , T = T _b × T _i ≧ 0.2.

The horizontal axis of FIG. 4, shows the product T and the total light transmittance T _i of the total light transmittance T _b and the insulating layer of the conductive layer (cathode 25), the vertical axis is emitted from the light emitting layer 26 The brightness of light (hereinafter referred to as light extraction efficiency η) was normalized and plotted. In FIG. 4, the horizontal axis indicates the value obtained by adjusting the total light transmittance T by varying the thickness of the conductive layer (cathode 25) and the insulating layer, and the vertical axis indicates the light extraction efficiency η. . The light extraction efficiency η is set when the luminance of light that can be generated in the light emitting layer 26 is set to 100 cd / m ₂ by controlling the applied voltage, and when the conductive layer (cathode 25) and the insulating layer are not present. The brightness 100 cd / m ₂ was normalized to 1.0, and the light extraction efficiency η was shown.

  In general, the light extraction efficiency η in the light emitter is required to be at least 0.05 or more. This is because if the total light transmittance (T) is less than 0.05, it is difficult to extract effective light outside the light emitter. Based on this definition, when the graph shown in FIG. 4 is observed in detail, it has been found that the total light transmittance T needs to be 0.2 or more, as shown in FIG. Further, as is clear from FIG. 4, when the total light transmittance (T) is 0.2 or 0.4, there is an inflection point of the light extraction efficiency η, and the inclination at both inflection points becomes large. Is known. The reason for this is not clear, but when the total light transmittance (T) is less than 0.2, the light generated in the light emitting layer is simply based on the product of the total light transmittance of the conductive layer and the total light transmittance of the insulating layer. It is considered that the light propagates in the longitudinal direction of the fiber due to the difference in the refractive index of the materials forming the two layers.

On the other hand, when the total light transmittance (T) is 0.4 or more, generally, the total light transmittance of the conductive layer and T _b, to a value close to the light extraction efficiency η based on a product of the total light transmittance T _i of the insulating layer It has been found that Thus, by making the product T of the total light transmittance T _b of the conductive layer and the total light transmittance T _i of the insulating layer 0.2 or more, the light generated in the light emitting layer of the fibrous light emitter can be efficiently externalized. Can be emitted. In view of power consumption and practical use, the total light transmittance (T) is preferably 0.4 or more.

Regarding the magnitude of the total light transmittance T _i of the total light transmittance T _b and the insulating layer of the conductive layer, a conductive layer and an insulating layer both of the light absorption and refractive index of the size of, such as further molecular orientation Because it depends on the size of the birefringence based on it, it is difficult to uniquely determine, but in order to efficiently emit light to the outside of the fibrous light emitter, compared to the total light transmittance T _b of the conductive layer Thus, it is preferable to increase the total light transmittance T _i of the insulating layer located in the outermost layer.

  Next, constituent materials of the fibrous light emitter according to the embodiment of the present invention will be described.

  It is necessary to select the material for the light emitting layer in consideration of processability (fibrosis) and various light emitting performance (desired light emission color, light emission luminance, light emission lifetime, etc.). , Preferably a π-conjugated material. Here, the π-conjugated material means a molecule in which a single bond and a double bond are connected to each other for a long time, such as benzene, and has the property that π electrons can be easily taken out with relatively little energy and move easily ( Katsumi Yoshino, “The story of OLED”, page 23, Nikkan Kogyo Shimbun). By forming the light emitting layer from a π-conjugated material, in addition to the light emitting layer, the core material (and the first conductive layer), the conductive layer (and the second conductive layer), and the insulating layer can be formed into a fibrous light emitter at once. Thus, the flexibility of the fibrous light emitter can be increased.

  π-conjugated materials include quinolinol derivatives, fluorene derivatives, phthalocyanine derivatives, triphenyldiamine derivatives, polyparaphenylene derivatives, distyrysarylene derivatives, oxadiazole derivatives, pyrazoline derivatives, polythiophene derivatives, poly (N-alkylcarbazole) derivatives It is preferable to use one kind selected from polyphenylacetylene derivatives, polyphenylene ethynylene derivatives, polyphenylene butadienylene derivatives, or a mixture containing one kind selected from these.

  As the core material, the light emitting layer, the conductive layer, and the insulating layer, it is preferable to use materials that are soluble in water or a solvent. This is because, in general, it is difficult to heat-melt a π-conjugated material, and it is difficult to use a normal melt composite spinning method or a multilayer thin film forming method. In addition, as will be described later, it is possible to obtain a target fibrous molded body by molding a material soluble in water or a solvent by a new molding method.

  That is, the core material, the light emitting layer, the conductive layer, and the insulating layer are made of materials soluble in water or a solvent, so that a multilayer structure can be formed at once using a molding method described later. As the solvent, in addition to aprotic solvents such as nitrobenzene, propylene carbonate, and acetic anhydride, proton solvents such as methanol and ethanol, or diluting solvents such as ethyl, toluene, and xylene can be used. It is not limited to solvents.

  As a material for the conductive layer, a composite of conductive nanoparticles and a light-transmitting polymer resin can be used. As a result, it is possible to ensure conductivity and light transmission in the visible light region, which are important as an electrode function.

  The conductive nanoparticles are not particularly limited as long as they are conductive and have a light-transmitting size (at least a size equal to or smaller than the wavelength in the visible light region). The particles are preferably a mixture containing at least one selected from Au, Ag, Pt, Pd, Ni, Al, Sn, Pb, Ti and C. For example, a conductive layer can be formed from a material in which particles of several tens of nanometers made of Au or C (which may be carbon nanotubes) are uniformly dispersed in polyethylene terephthalate (PET). The dispersion amount of the nanoparticles cannot be uniquely determined depending on the kind and particle size of the nanoparticles used or the kind of the polymer resin used as a matrix, but is about several to ten and several weight%. It is preferable to do. In order to prevent secondary aggregation between the nanoparticles, the nanoparticles may be subjected to a surface treatment. The diameter of the nanoparticles is preferably about 50 nm or less. By setting the particle size to 50 nm or less, the particle size of the conductive nanoparticles becomes smaller than the wavelength λ (380 to 780 nm) of incident light in the visible light region (approximately 1/10 or less of the particle diameter), and light Increases transmittance.

The conductive layer materials include doped polypyrrole, doped polyaniline, doped polythiophene, doped polyacetylene, and doped polyacethilene. At least one selected from doped polyisothianaphtene and derivatives thereof may be used. The doping material (also referred to as a dopant) varies depending on the type of conductive polymer used, whether it is a donor property (a property that takes away electrons), or an acceptor property (a property that gives electrons). B ₁₀ Cl _2-10 , Bu ₄ NBF _4- , ClO _4-, etc. can be used to make the molecular polythiophene acceptor, and Li ₊ , K _+, etc. can be used to make it a donor. Can do. By appropriately using a doping material under appropriate conditions, a conductive layer having a conductivity σ = 10 ₂ S / cm and a total light transmittance T in the visible light region of about 78% can be obtained.

  Furthermore, as the material for the conductive layer, at least one material selected from polyethylene dioxythiophene (PEDOT), polypropylene oxide (PO), and derivatives thereof can be used. The exemplified materials have particularly good water dispersibility, and it becomes relatively easy to form a thin film while ensuring conductivity and total light transmittance.

For example, a composite in which polyethylenedioxythiophene (PEDOT) and polystyrene sulfonic acid (PSS) are dispersed at an appropriate ratio has a conductivity σ = 10 ₃ S / cm and a total light transmittance (T) of about 82%. It is also possible to ensure, and it is preferable as the conductive layer.

  As the material for the insulating layer, a light-transmitting material is preferably used. This is because, as is clear from FIG. 1 (a), it is possible to ensure electrical insulation with respect to the conductive layer serving as the electrode of the fibrous light emitter and to emit light from the light emitting layer to the outside. . In addition, such a material is preferably a polymer resin material having a sigma bond, such as polyethylene (PE), polypropylene (PP), polystyrene (PSt), polyethylene terephthalate (PET), polyethylene naphthalate (PEN). , Polycarbonate (PC), polymethyl methacrylate (PMMA), polyethersulfone (PES), polyamide (PA), polyimide (PI), and derivatives thereof are preferable. Thereby, it can be set as the insulating layer which has a light transmittance, and also has high electrical insulation and flexibility.

Further, as will be described later, since a plurality of types of resins are discharged by receiving a shearing stress in the die, the fibrous luminous body has a refractive index (n _z ) in the fiber axis direction of two axes perpendicular to each other in the fiber cross section. (X-axis, Y-axis) x direction of the refractive index of (n _x), than the refractive index in the y-direction (n _y), tends to increase. Since the anisotropy of these three refractive indexes (that is, birefringence Δn) affects the light emission or incidence direction, Δn should be as small as possible, and Δn ≦ 0.1 is preferable. On the other hand, when the birefringence Δn exceeds 0.1, the emission or incidence in a specific direction (angle) becomes more prominent, and not only the aimed color can not be obtained, but also the purity of the color development becomes turbid and the quality becomes low. Above, it is not preferable.

  Next, a method for manufacturing the fibrous light emitter according to the embodiment of the present invention will be described.

  In the method for manufacturing a fibrous light emitter according to the embodiment of the present invention, the conductive material for the core material is disposed at the center of the molding die, and the light emitting layer material is disposed on the outer periphery of the conductive material for the core material. The material for the conductive layer and the material for the insulating layer may be sequentially layered, arranged as a solution in a state soluble in water or a solvent, respectively, and discharged using a known wet spinning method. More preferably, while applying voltage to each solution, joining and discharging (injection molding) within the die to form a fibrous light emitter, adhesion stability at the interface, and different materials formed at the interface This is desirable from the viewpoint of controllability of the potential barrier height between the two.

  As described above, the first conductive layer, the light emitting layer, the second conductive layer, and the insulating layer are made of a material that is soluble in water or a solvent, so that a multilayer structure can be used even if it is a thermally infusible material. Can be molded at once.

  Furthermore, an example of the fibrous light emitter shown in FIG.

  As described above, the fibrous light emitter 1 shown in FIG. 1A is a concentric core formed of four layers of a fibrous core material 2, a light emitting layer 3, a conductive layer 4, and an insulating layer 5. It has a circular structure.

  A method for forming a multilayer structure having four or more layers by heat-melting the above four materials is equipped with a known base for forming a multilayer structure (for example, Japanese Patent Publication No. 57-20842, Japanese Patent Publication No. 53-8806). Although it is possible to use the melt-combined spinning apparatus, it is generally difficult to thermally melt the π-conjugated material. For this reason, a π-conjugated material that is soluble in water or a solvent is used, or after being devised so that it can be solubilized in a certain solvent, a special composite spinning method (for example, electrospinning method) is used to It has been found that a shaped light emitter can be formed. In the electrospinning method, a high voltage is applied to a polymer solution and the solution is sprayed to form a fiber. The thickness of the fiber depends on the applied voltage, the solution concentration, and the spray distance.

  Furthermore, a specific material is mentioned and the manufacturing method of a fibrous light-emitting body is demonstrated.

  First, as a material for the conductive core material 2 and the conductive layer 4 soluble in water or a solvent, a polyethylene-dioxythiophene (PEDOT) / polystyrene sulfonic acid (PSS) aqueous dispersion composite (as a weight% ratio, 1.6 / 1) is prepared, and polyphenylene vinylene (PPV) diluted with toluene is prepared as a light emitting layer, and polyethylene terephthalate (PET) diluted with o-chlorophenol is prepared as an insulating layer.

  Next, using the prepared three types of solutions, injection molding is performed using an electrospinning device to obtain a concentric circular structure. FIG. 5 shows an enlarged view of the solution storage part located in the hopper part above the electrospinning device used here. As shown in FIG. 5, the solution storage unit 29 is divided into a base 30 so that injection molding solutions can be individually introduced. A solution a for the conductive core material 2 (for example, an anode) is introduced into the central portion of the base 30, and a solution b for the light emitting layer 3 and a conductive layer 4 (for example, a cathode) are sequentially formed on the outer periphery thereof. And the solution d for the insulating layer 5 are introduced, and electrode rods 31 to 34 are arranged in the solutions a to d, respectively. And the voltage AD of each solution is suitably set by making the collection plate 36 arrange | positioned in the front-end | tip part of the last discharge hole 35 of a nozzle | cap | die 30 into a minus electric potential.

  When each solution diluted with a solvent is introduced into the solution storage part 29 of the electrospinning device shown in FIG. 5, the solution is merged concentrically within the die 30, and then it is injection molded from the discharge hole and solidified. A fiber having a four-layer concentric structure can be obtained continuously. Note that the concentration of each solution, the magnitude of the applied voltage, and the distance between the final discharge hole 35 and the collection plate 36 are extremely important factors in forming the fibrous structure. The concentration of each solution depends on the material used, the environment temperature in use, and the like, and thus cannot be set to a specified value. However, it is generally preferable to set the concentration to about several tens of cps to about several thousand cps. Furthermore, the voltage applied to each solution is preferably set to several thousand V to several tens of thousands V in order to form a fibrous structure. The fibrous structure can be discharged from the final discharge hole 35 by applying the voltage between the electrode rod (for example, Pt) in each solution and the collecting plate 36 (with a negative potential). It becomes. Here, the distance between the final discharge hole 35 and the collecting plate 36 is preferably about several tens of centimeters to several hundreds of centimeters at room temperature from the viewpoint of curing the fibrous structure. In addition, when the applied voltage is too low or the polarity of the voltage applied between the electrode rod and the collecting plate 36 is reversed, a continuous fibrous structure cannot be formed, and the solution is discharged from the inkjet port. As the liquid is discharged from the liquid, it becomes a solution bubble and stays attached to the collecting plate 36.

  Furthermore, the applied voltage when injection molding by combining two types of materials will be described.

When water-dispersed composite containing polyethylenedioxythiophene (PEDOT) and polystyrene sulfonic acid (PSS) (1 / 1.6 by weight ratio), the voltage is about 5000-6500V and polyphenylene vinylene diluted with toluene In the case of (PPV), the voltage is preferably about 6500 to 7500 V, and in the case of polyethylene terephthalate (PET) diluted with o-chlorophenol, the voltage is preferably about 7000 to 8100 V.

Further, when the fibrous light-emitting body is discharged (injection molding) all at once using the electrospinning method to form a multilayer structure, as shown in FIG. 3, the potential barrier ΔΦ _{a at} the interface between the core material 2 and the light-emitting layer 3 is obtained. And the potential barrier ΔΦ _{b at} the interface between the conductive layer 4 and the light-emitting layer 3 was found to be extremely small. Although the reason for this is not clear, in the concentric circular structure (multilayer structure) body of the present invention, compared to the conventional multilayer thin film stacking method, that is, the conventional multilayer by layer by layer, the formation of the interface of each layer Since the process is formed at once in the die, the reason is that the potential barrier height ΔΦ at the interface of each layer made of different materials is also stabilized in terms of energy balance, that is, smaller.

  As a conventional method for forming a multilayer thin film stack by Layer by layer, usually a dry process (for example, a vacuum deposition method, an electron beam method, a plasma polymerization method, a sputtering method, an ion plating method, a molecular beam epitaxy method, etc.), or A wet process (for example, a spin coating method, a casting method, a spray method, a dipping method, an LB method, a composite spinning method, or the like) can be used, and a vacuum deposition method will be described as an example.

In the vacuum deposition method, deposition is performed under vacuum, but in reality, it is in an environment of about 10 ₋₆ to 10 ₋₈ Torr and is not in a complete vacuum state, and there is a residual gas such as oxygen. . Furthermore, in order to form a certain layer under vacuum, individual island-shaped particles are attached to the substrate, and then the closest particles are aggregated to grow into larger particles. This grain growth and the formation of a continuous layer associated therewith can be regarded as a kind of thermally stable state. After this, since the second layer is formed in the same manner, it is considered that a clear interface with a different material is formed between the first layer and the second layer.

  On the other hand, the manufacturing method of the fibrous luminous body referred to here is, for example, for a core material having conductivity, for a light emitting layer, in a composite base installed at the lower part of an electrospinning apparatus (see FIG. 5), The original solution of the concentric circular structure (multilayer structure) is formed at a time by dividing and joining the four solutions for the conductive layer and further for the insulating layer, and the concentric circular structure (from the final die hole) Multi-layer structure) Thinned and solidified while maintaining the shape of the body.

  As described above, by using the above-described method for manufacturing a fibrous light emitter, it is possible to continuously form a concentric circular structure (multilayer structure) at a stretch, thereby achieving simplification of the process and cost reduction based thereon. be able to. In addition, the multi-layer structure formation process is essentially different from the conventional layer-by-layer process, and a new method is used in which the solution for layer formation is divided and merged in the die and then discharged from the final discharge hole at once. Therefore, compared with the conventional method by Layer by layer, the advantage that the height Φ of the potential barrier at the interface of each layer can be easily lowered from 1/2 to 1/4 is also born. Voltage drive and long life can be realized. Furthermore, since the multilayer structure can be continuously formed at a stretch, the process for producing the multilayer structure can be reduced and the cost can be reduced.

  Further, the fibrous light emitter according to the present invention is a light emitter produced by using the above-mentioned fibrous light emitter production method, and by using this fibrous light emitter, twisted yarn, woven fabric, knitted fabric, apparel and nighttime It can be used as fabrics such as clothes (clothing) for improving visibility for pedestrians and automobile seats, as well as lighting bodies and novel design bodies that exhibit light source colors.

  FIG. 6 and FIG. 7 show examples of articles formed using fibrous light emitters. FIGS. 6 (a) to (c) are examples of fabrics, and FIGS. 7 (a) and 7 (b) are for automobiles. It is the application example used for the material of the sheet. Since the fibrous luminous body has the same flexibility as ordinary fibers, it can be woven into various shapes as shown in FIGS. 7 (a) and 7 (b). It can also be.

  Hereinafter, although it demonstrates based on an Example more concretely, it is not limited to the illustrated Example.

[Example 1]
In Example 1, a fibrous light emitter having a concentric circular structure (multilayer structure) shown in FIG. 1 (a) was produced. Regarding the material of each layer constituting the fibrous luminous body, as a material for the cathode (core material), an aqueous dispersion composite solution of polyethylenedioxythiophene (PEDOT) and polystyrene sulfonic acid (PSS) (PEDOT / PSS = 1 / 1.6) ), Solution of light emitting layer, polyphenylene vinylene (PPV) diluted with toluene, and material for anode (conductive layer), water-dispersed composite of polyethylene dioxythiophene (PEDOT) and polystyrene sulfonic acid (PSS) described above As a solution (PEDOT / PSS = 1 / 1.6) and an insulating layer material, a polyethylene terephthalate (PET) solution diluted with o-chlorophenol was prepared.

  Next, after putting each prepared solution into the solution storage part in the electrospinning apparatus shown in FIG. 5, the electrode rod is arranged, a high voltage is applied between the electrode rod and the collecting plate, and the final discharge is performed. A concentric circular structure (multilayer structure) was discharged from the hole to obtain a fibrous light emitter. Although the thickness of each layer can be changed by controlling the applied voltage, the applied voltage to the PEDOT / PSS solution for the cathode (core material) is 6000 V, and the applied voltage to the PPV solution for the light emitting layer is 6500 V. The applied voltage to the PEDOT / PSS solution for the anode (conductive layer) was 6100 V, the applied voltage to the solution for the insulating layer was 7800 V, and the distance between the final discharge hole and the collecting plate was 100 cm.

The total light transmittance Tb, which is the product of the total light transmittance T _{b in} the visible light region of the conductive layer and the total light transmittance T _{i in} the visible light region of the insulating layer, is the same on the quartz glass plate. It can calculate by using the sample which apply | coated each layer of thickness, and measuring using a spectrophotometer (the Hitachi Ltd. make, U-4000). In addition, the luminance of light emitted from the obtained fibrous luminous body was measured with a luminance meter (CA-1500 manufactured by Konica Minolta). At this time, a DC voltage of 10 V was applied as a constant value between the anode and the cathode.

[Example 2]
In Example 2, the thickness of each layer was changed by controlling the applied voltage as compared to Example 1. Specifically, the voltage applied to the PEDOT / PSS solution for the cathode (core material) is 6000 V, the voltage applied to the PPV solution for the light emitting layer is 6500 V, and the voltage is applied to the PEDOT / PSS solution for the anode (conductive layer). A fibrous light-emitting body having a concentric circular structure (multilayer structure) was manufactured under the same conditions as in Example 1 except that the voltage was changed to 5800 V and the voltage applied to the solution for the insulating layer was changed to 7600 V.

Example 3
In Example 3, compared to Example 1, the thickness of each layer was changed by controlling the applied voltage. Specifically, the voltage applied to the PEDOT / PSS solution for the cathode (core material) is 6000 V, the voltage applied to the PPV solution for the light emitting layer is 6500 V, and the voltage is applied to the PEDOT / PSS solution for the anode (conductive layer). A fibrous light emitter having a concentric circular structure (multilayer structure) was manufactured using the same method as in Example 1 except that the voltage was changed to 5500 V and the voltage applied to the solution for the insulating layer was changed to 7200 V. .

Example 4
In Example 4, a fibrous light emitter having a rectangular structure (multilayer structure) shown in FIG. 1B was manufactured. Regarding the material of each layer constituting the fibrous luminous body, as a solution for the cathode (core material), an aqueous dispersion composite solution of polyethylenedioxythiophene (PEDOD) and polystyrene sulfonic acid (PSS) (PEDOT / PSS = 1 / 1.6) ), As a solution for the light emitting layer, a polyphenylene vinylene (PPV) solution diluted with toluene, and as a solution for the anode (conductive layer), the above-mentioned water-dispersed composite of polyethylene dioxythiophene (PEDOD) and polystyrene sulfonic acid (PSS) As a solution (PEDOT / PSS = 1 / 1.6) and a solution for an insulating layer, a polyethylene terephthalate (PET) solution diluted with O-chlorophenol was prepared. Except for this, a fibrous light emitter was produced using the same method as in Example 1.

Example 5
In Example 5, a fibrous light emitter having a rectangular structure (multilayer structure) shown in FIG. Regarding the material of each layer constituting the fibrous luminous body, as a material for the cathode (core material), an aqueous dispersion composite solution of polyethylenedioxythiophene (PEDOD) and polystyrene sulfonic acid (PSS) (PEDOT / PSS = 1 / 1.6) ) Polyfluorene (PFO) solution diluted with xylene as the material for the light emitting layer, 10% by weight of carbon nanotube (SWNT) dispersed in isopropyl alcohol as the material for the anode (conductive layer), and insulating layer As a material for the preparation, a polyethylene naphthalate (PEN) solution diluted with O-chlorophenol was prepared.

  The solution for the above four layers is put into the solution storage part in the electrospinning apparatus shown in FIG. 5, and the electrode rod is arranged, and a high voltage is applied between the electrode rod and the collecting plate, so that the final discharge is performed. A concentric circular structure (multilayer structure) was discharged from the hole to obtain a fibrous light emitter. The voltage applied to each layer is 6000V applied to the PEDOT / PSS solution for the cathode (core material), 6500V applied to the PPV solution for the light emitting layer, and applied to the solution for the anode (conductive layer). The voltage was 6300 V, and the voltage applied to the insulating layer solution was 7900 V. Otherwise, a fibrous light emitter was produced using the same method as in Example 1.

Example 6
In Example 6, a fibrous light-emitting body having a concentric structure (a multilayer structure was formed on the outer periphery of a non-conductive substrate) shown in FIG. 2A was manufactured. Regarding the material of each layer constituting the fibrous luminous body, as a material for the cathode (core material), an aqueous dispersion composite solution of polyethylenedioxythiophene (PEDOT) and polystyrene sulfonic acid (PSS) (PEDOT / PSS = 1 / 1.6) ), A solution for the light emitting layer, a polyfluorene solution diluted with xylene, a solution for the anode (conductive layer), a solution in which 10% by weight of carbon nanotubes (SWNT) are dispersed in isopropyl alcohol, and a solution for the insulating layer A polyethylene terephthalate (PET) solution diluted with xylene was prepared.

  The solution for the above four layers is put into the solution storage part in the electrospinning apparatus of FIG. 5, and further, an electrode rod is arranged, and a high voltage is applied between the collecting plate and the concentric circle from the final discharge hole. The fibrous structure (multilayer structure) was discharged to obtain a fibrous light emitter. The voltage applied to each layer is 6000 V for the cathode (core material) PEDOT / PSS solution, 6800 V for the light emitting layer PFO solution, and the anode (conductive layer) solution. The voltage was 6300 V, and the voltage applied to the insulating layer solution was 7600 V. A fibrous light emitter was manufactured using the same method as in Example 1 except that the applied voltage was changed.

[Comparative Example 1]
In Comparative Example 1, a base material, a second conductive layer, a light emitting layer, and a first conductive layer were sequentially stacked on the base material to obtain a light emitting body of a multilayer laminated structure. Regarding the material of each layer constituting the light-emitting body of the multilayer laminated structure, a water-dispersed composite solution (PEDOT) of polyethylenedioxythiophene (PEDOT) and polystyrene sulfonic acid (PSS) is used as a solution for the cathode (first conductive layer). /PSS=1/1.6), solution for the light emitting layer, polyphenylene vinylene (PPV) diluted with toluene, solution for the anode (second conductive layer), polyethylene dioxythiophene (PEDOT) and polystyrene as described above A polyethylene terephthalate (PET) solution diluted with o-chlorophenol was prepared as an aqueous dispersion composite solution of sulfonic acid (PSS) (PEDOT / PSS = 1 / 1.6) and an insulating layer.

  First, a PEDOT / PSS solution for a cathode (first conductive layer) was formed on a quartz glass substrate by a spin coating method and solidified to a layer thickness of 150 nm. Subsequently, a PPV solution for the light emitting layer is formed on the cathode by spin coating and solidified to a layer thickness of 60 nmn, and further, a PEDOT / PSS solution for the anode (second conductive layer) is formed thereon. Solidified to a layer thickness of 150 nm. Finally, a solution for an insulating layer was formed and solidified to obtain a light-emitting body having a multilayer laminated structure with a layer thickness of 100 nm.

[Comparative Example 2]
In Comparative Example 2, as in Comparative Example 1, a light-emitting body having a multilayer laminated structure was manufactured. As the material of each layer constituting the luminous body, as a solution for the cathode (first conductive layer), an aqueous dispersion complex solution of polyethylenedioxythiophene (PEDOT) and polystyrene sulfonic acid (PSS) (PEDOT / PSS = 1 / 1.6), as a solution for the light emitting layer, a polyfluorene (PFO) solution diluted with xylene, and as a solution for the anode (second conductive layer), a solution in which 10% by weight of carbon nanotubes (SWNT) are dispersed in isopropyl alcohol, A polyethylene terephthalate (PET) solution diluted with O-chlorophenol was prepared as a solution for the insulating layer.

  First, a PEDOT / PSS solution for a cathode (first conductive layer) was formed on a quartz glass substrate by a spin coating method and solidified to a layer thickness of 150 nm. Subsequently, a PFO solution for the light-emitting layer is formed on the cathode (first conductive layer) by a spin coating method and solidified to a layer thickness of 80 nmn, and then the anode (second conductive layer) is further formed thereon. ) SWNT solution was formed and solidified to a layer thickness of 150 nm. Finally, a solution for an insulating layer was formed and solidified to produce a light emitting body having a multilayer structure with a layer thickness of 110 nm.

For each of the light emitters of Examples 1 to 6, Comparative Example 1 and Comparative Example 2, the potential barrier height Φ at the interface between the core material (first conductive layer) and the light emitting layer, and the light emitting layer The value of the potential barrier height Φ at the interface between the conductive layer and the conductive layer (second conductive layer) was measured using an atmospheric photoelectron spectrometer (AC-2, manufactured by Riken Keiki Co., Ltd.). The measurement results are shown in Table 1.

  As shown in Table 1, when comparing the height of the potential barrier at each interface between the light emitting layer and the core material (first conductive layer) and the conductive layer (or second conductive layer) arranged on both sides of the light emitting layer, It has been found that the height of the potential barrier of the example is smaller than that of the comparative example. Among the examples, as the height of the potential barrier is lowered, the luminance is increased, the light emission performance is improved, and further, the light emission performance is further improved when the product T of the total light transmittance is increased. did.

It is a figure which shows an example of the fibrous light-emitting body which concerns on embodiment of this invention, (a) is the schematic diagram which made cross-sectional shape circular, (b) is the schematic diagram which made cross-sectional shape the rectangle. It is a figure which shows an example of the fibrous light-emitting body which concerns on the other form of this invention, (a) is the schematic diagram which made cross-sectional shape circular, (b) is the schematic diagram which made cross-sectional shape the rectangle. It is a figure explaining the light emission mechanism when a voltage is applied to the fibrous light-emitting body which concerns on embodiment of this invention. Total light transmittance of the conductive layer T _b and the product T and the total light transmittance T _i of the insulating layer is a graph showing the relationship between the brightness of the light emitted from the light emitting layer (light extraction efficiency eta). It is an enlarged view of the solution storage part of the electrospinning apparatus used in the manufacturing method of the fibrous light-emitting body based on embodiment of this invention. An example of the article | item formed using the fibrous light-emitting body which concerns on embodiment of this invention is shown, (a)-(c) is an enlarged top view of a textile fabric. An example of the article | item using the fibrous light-emitting body which concerns on embodiment of this invention is shown, (a), (b) is a figure which shows the example used as a material of the sheet | seat for motor vehicles.

Explanation of symbols

1 ... Fibrous luminous body,
2 ... fibrous core,
3 ... light emitting layer,
4 ... conductive layer,
5 ... Insulating layer,
6 ... Power supply,

Claims (16)

A fibrous core made of a conductive material;
A light emitting layer provided on the outer periphery of the core;
A conductive layer provided on the outer periphery of the light emitting layer;
And an insulating layer provided on an outer periphery of the conductive layer, wherein a fibrous luminescent material emits light by applying a voltage between the core material and the conductive layer.  The fibrous light-emitting body according to claim 1, wherein the conductive layer and the insulating layer have light transmittance in a visible light region from a wavelength of 380 nm to a wavelength of 780 nm. When the total light transmittance in the visible light region of the conductive layer is T _b , the total light transmittance of the insulating layer is T _i , and the product of the total light transmittance of both is T, T = T _b × T _i ≧ The fibrous light-emitting body according to claim 2, wherein 0.2 is satisfied.   The fibrous light-emitting body according to any one of claims 1 to 3, wherein the light-emitting layer is made of a π-conjugated material.   The π-conjugated materials include quinolinol derivatives, fluorene derivatives, phthalocyanine derivatives, triphenyldiamine derivatives, polyparaphenylene derivatives, distyrysarylene derivatives, oxadiazole derivatives, pyrazoline derivatives, polythiophene derivatives, poly (N-alkylcarbazole) derivatives. 5. The fibrous light-emitting body according to claim 1, comprising at least one selected from the group consisting of polyphenylacetylene derivatives, polyphenyleneethynylene derivatives, and polyphenylenebutadinylene derivatives.   6. The fibrous light emitter according to claim 1, wherein the core material, the light emitting layer, the conductive layer, and the insulating layer are made of a material soluble in water or a solvent.   The fibrous light-emitting body according to claim 6, wherein the conductive layer is made of a composite of conductive nanoparticles and a light-transmitting polymer resin.   The fibrous light-emitting body according to claim 7, wherein the conductive nanoparticles include at least one selected from Au, Ag, Pt, Pd, Ni, Al, Sn, Pb, Ti, and C. .   The conductive layer includes at least one selected from doped polypyrrole, doped polyaniline, doped polythiophene, doped polyacetylene, doped polyisothianaphthene, and derivatives thereof. The fibrous light-emitting body according to claim 6.   The fibrous light-emitting body according to claim 6, wherein the conductive layer includes at least one selected from polyethylene dioxythiophene, polypropylene oxide, and derivatives thereof.   The insulating layer includes at least one selected from polyethylene, polypropylene, polystyrene, polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polymethyl methacrylate, polyethersulfone, polyamide, polyimide, and derivatives thereof. The fibrous light-emitting body according to any one of claims 1 to 10. A conductive material for the core material is arranged in the center of the molding die, and the light emitting layer material, the conductive layer material, and the insulating layer material are sequentially layered on the outer periphery of the conductive material for the core material, Place each as a solution that is soluble in water or solvent,
A method of manufacturing a fibrous light emitter, wherein a voltage is applied to each solution and injection molding is performed simultaneously to form a fibrous light emitter.   The fibrous light-emitting body manufactured using the manufacturing method of the fibrous light-emitting body of Claim 12.   An article of either a display body or an illumination body using the fibrous light emitter according to any one of claims 1 to 13.   The clothing using the fibrous light-emitting body of any one of Claims 1 thru | or 13.   An automotive seat using the fibrous light emitter according to any one of claims 1 to 13.

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