RU2445340C2 - Luminous body - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: inorganic composition for producing electroluminescent material contains the following, pts.wt: 80-95 semiconductor compound consisting of group II and group VI elements; 0.001-3 iridium source or a combination of an iridium source and at least one source of metal other than iridium; 3-9 activator. To obtain electroluminescent material, the inorganic composition is subjected to an explosion using a propellant and/or blasting explosive in a sealed vessel followed by thermal treatment. The obtained electroluminescent material is used as a light-emitting layer between electrodes of an inorganic electroluminescent device whose brightness when excited with direct current is equal to or higher than 10000 cd/m².

EFFECT: invention not only increases brightness but also prolongs the service life of the light-emitter.

12 cl, 5 dwg, 2 tbl, 3 ex

Description

Technical field

The present invention relates to a luminous body, and more particularly, to an inorganic composite for producing a luminescent material and a method for producing this composite and a luminescent material. More specifically, the invention relates to a method for producing an inorganic composite, comprising subjecting the inorganic composition to explosion using a propellant and / or blasting explosive in an airtight vessel, a method for producing an inorganic composite to produce a luminescent material in which an inorganic composition containing an iridium element is used, and luminescent material obtained by heat treatment of this inorganic composite. Since the luminescent material of the present invention has excellent emission efficiency, it can preferably be used for an electroluminescent device (EL device).

The present invention also relates to an inorganic composition. More specifically, the invention relates to an inorganic composition comprising a semiconductor compound as a main component, said inorganic composition comprising an iridium element. The inorganic composition of the present invention can preferably be used as a starting material for a luminescent material to produce an inorganic EL device that exhibits high photoconversion of electrical energy or photo-energy.

In addition, the present invention relates to an inorganic EL device capable of emitting under the influence of direct current.

State of the art

An electroluminescent device is a light emitting device that uses the luminescence phenomenon that occurs when an electric field is applied to a substance and can be roughly classified into an organic EL device based on an organic material that includes metal complexes such as aluminoquinolinol or conjugated macromolecules such as polyphenylene vinyl, and an inorganic EL device based on inorganic material such as zinc sulfide or oxygen-containing aluminum salts.

Since the inorganic EL device has excellent durability and low power consumption compared to the organic EL device, it is expected that the inorganic EL device will be used in an image reproduction system such as a light and large flat display panel. In addition, an inorganic EL device can be classified into a dispersion-type EL device, obtained by dispersing a luminescent material in an inorganic or organic binder, and a thin-film EL device using a thin crystalline film of a luminescent material. Although devices of each of these types can act as a light-emitting device when applying direct current or alternating current, in general, a thin-film EL device is best as a device with high brightness and low power consumption.

Moreover, in order to produce an image reproduction system, luminescent materials are required that exhibit such emission as red, green, blue or similar radiation. It is known in the prior art that since an inorganic EL device is made on the basis of a compound of groups II-VI, consisting of an element of group II or an element of group VI, such as ZnS or SrS,

the material obtained by adding a small amount of Mn (manganese) to ZnS emits a yellow-orange light (for example, see Non-Patent Document 1);

the material obtained by adding Tb (terbium) and the like to ZnS emits green light (for example, see Non-Patent Document 2); and

the material obtained by adding Cu (copper) and the like to ZnS emits blue light (for example, see Non-Patent Document 3).

In General, these materials can be obtained by the process of introducing by alloying a small amount of metals into the main carrier, such as calcination (for example, see patent document 1), or also by alloying during the preparation of particles in the liquid phase, etc. (for example, see patent document 2).

An inorganic EL device can be made by forming an electrode on each of the opposite sides of the EL materials, and it can demonstrate the luminescence phenomenon inherent in the used inorganic EL material when a predetermined voltage is applied between the two electrodes of the inorganic EL device.

However, using the inorganic EL materials described above, it is difficult to obtain a light emitter having a color and emission intensity suitable for an image reproduction system. The luminescent bodies obtained so far have problems in that they do not have sufficient brightness and that they have a shorter life than other lighting (Patent Document 3). Brightness can be increased by applying a higher voltage. However, the life of the light emitter tends to shorten with increasing applied voltage. Therefore, it is necessary to choose either brightness or service life.

[Non-Patent Document 1] Journal of Crystal Growth 169 (1996) p. 33-39

[Non-Patent Document 2] Applied Surface Science 244 (2005) p.524-527

[non-patent document 3] Journal of Luminescence 99 (2002) p.325-334

[patent document 1] Japanese patent publication Kokai Hei08-183954

[patent document 2] Japanese patent publication Kokai 2003-73119

[patent document 3] Japanese patent publication Kokai 2002-241753

Disclosure of invention

Problems Solved by the Invention

An object of the present invention is to provide a new method for producing a luminescent material having a combination of high levels of brightness and a light emitter life, and a new inorganic composite that can be used for this method, and a new luminescent material.

Another objective of the present invention is to provide an inorganic composition that can be used as a starting material for producing a luminescent material capable of emitting with high efficiency due to its new composition of materials.

Another objective of the present invention is to provide an inorganic EL device capable of being driven by direct current, whereby it is suitable for use as light sources for mobile applications and high brightness applications such as lighting.

Means for solving these problems

The present invention provides the following.

[1] A method for producing an inorganic composite to produce a luminescent material, the method comprising exposing the inorganic composition, mainly containing a semiconductor compound, to explosion using a propellant and / or blasting explosive in an airtight vessel.

[2] A method for producing an inorganic composite according to [1], wherein the inorganic composition contains an iridium element.

[3] An inorganic composition containing a semiconductor compound as a main component and an iridium element.

[4] The inorganic composition according to [3], containing a transition metal, halogen or rare earth element.

[5] The inorganic composition according to [3] and [4], wherein the semiconductor compound is a semiconductor compound of groups II-VI.

[6] An inorganic composite for producing a luminescent material, which is obtained from an inorganic composition according to any one of [3] to [5].

[7] A method for producing an inorganic composite, the method comprising heat treating the inorganic composition according to any one of [3] to [5].

[8] A method for producing a luminescent material, moreover, this method includes the heat treatment of an inorganic composite obtained by the method according to [1] or [7].

[9] Luminescent material obtained by the method according to [8].

[10] An inorganic EL device using luminescent material according to [9].

[11] An inorganic EL device comprising:

at least two electrodes; and

a light emitter layer consisting of a luminescent material according to [9] and provided between the electrodes;

wherein the brightness of the device attained during actuation of the constant current is 10000 cd / m ² or more.

[12] The inorganic EL device according to [11], wherein the thickness of the light emitter layer is from 0.05 μm to 100 μm.

[13] The inorganic EL device according to [11] or [12], wherein the light emitting layer comprises a plurality of light emitting layers having different compositions.

Advantages of the Invention

The present invention may provide a method for producing an inorganic composite. The luminescent material obtained by heat treatment of an inorganic composite obtained by the production method of the present invention has an improved brightness as well as an improved service life of the luminescent body and, therefore, can be used appropriately for an inorganic EL device.

The present invention may also provide an inorganic composition comprising an iridium element. An inorganic EL device made using the inorganic composition of the present invention as a starting material for producing a luminescent material can emit with high efficiency due to its composition of materials. Thus, the inorganic composition of the present invention can be used as a luminescent material to obtain a beautiful luminous body without processes such as grinding, which causes new problems, such as agglomeration.

The present invention can also provide an inorganic EL device capable of being driven by direct current and suitable for use in mobile applications. Such a device has a high brightness, it can provide light sources suitable for different applications.

Brief Description of the Drawings

Figure 1 is a schematic view of a high pressure resistant vessel.

Figure 2 is an enlargement of the reaction chamber of a high pressure resistant vessel.

Figure 3 is a sectional view of an EL device made using the luminescent material obtained in Examples 1-1 to 1-3 and Comparative Example 1-1.

4 is a perspective view showing a key part of a typical configuration of a conventional inorganic EL device.

FIG. 5 is a schematic cross-sectional view of a key part of an inorganic EL direct current device made in Examples 3-1 to 3-2 and a reference example.

The best embodiment of the invention

The inorganic composition of the present invention can be used as a starting material for producing a luminescent material. An inorganic composite for producing a luminescent material can be prepared by subjecting the inorganic composition to an alloying treatment, such as blasting and heat treatment. Further, a luminescent material can be prepared by heat treatment of a given inorganic composite. The resulting luminescent material can be formed into a layer as a light emitter layer in an inorganic EL device.

(Inorganic composition)

Inorganic compositions containing a semiconductor compound as a main component have been used in various fields, including luminescent materials such as fluorescent and phosphorescent materials, and light-preserving materials. Some compositions perform the function of emitting light when receiving electrical energy and are mainly used as a light source, and some of these compositions are used in displays and other applications.

However, currently known materials can be used only in limited applications, since they have problems such as heat generation or power consumption, due to their insufficient efficiency of photoconversion of electrical energy. Attempts are still being made to improve energy conversion efficiency, and the following examples of such attempts are known:

(1) the process of grinding material into ultrafine particles (patent document 4);

(2) the process of selecting an alloying material such as cerium (non-patent document 4);

(3) the process of additional co-alloying with chloride or the like (non-patent document 5); and

(4) modification of the manufacturing process of the device (Non-Patent Document 6).

[patent document 4] Japanese patent publication Kokai 2003-173878

[Non-Patent Document 4] Journal of Applied Physics, vol. 93, 12 , Jun 15, 2003, p. 9597-9603

[Non-Patent Document 5] Applied Physics Letters, vol. 76, 10 , Mar, 2000, p. 1276

[Non-Patent Document 6] Japanese Journal of Applied Physics, Part 1: Regular Papers & Short Notes & Review Papers, vol. 33, 10 , Oct, 1994, p. 5801-5806.

(1) According to Patent Document 4, a process for grinding a material into ultrafine particles disclosed therein can be carried out without any limitation. However, when the material is mechanically pulverized into ultrafine particles, there is a problem of contamination by impurities from the machine used during the grinding of the material. In addition, ultrafine particles typically agglomerate during storage. Such agglomeration gives the same behavior as in the case when large particles are used. There is a problem of secondary agglomeration, and in order to solve this problem, it is necessary to use a dispersing agent, which leads to low efficiency.

(2) Regarding the alloying and co-alloying materials disclosed in Non-Patent Documents 4 and 5, no formulation has yet been found to provide a sufficiently high efficiency.

(3) Modifying the manufacturing process of the device into a special process using a magnetron, as disclosed in Non-Patent Document 6, gives uneconomical results, such as complex manufacturing of the device, a lengthy process, an expensive system, and an increase in the total amount of energy.

Thus, there is a need for an inorganic composition that can be used as a starting material for a luminescent material capable of efficiently emitting light due to a new formulation of the inorganic composition. The inorganic composition of the present invention solves the above problems of the prior art.

If the inorganic composition contains a transition metal, such as iridium, manganese, copper, silver, gold and hafnium, and a rare earth element, such as cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium , lutetium and yttrium, a given transition metal, etc. can be introduced into a semiconductor compound in an inorganic composition by the doping treatment described below and can act as an emission center. In particular, the inorganic composition of the present invention is characterized in that it contains an iridium element as a transition metal.

Semiconductor connection:

The semiconductor compound used in the present invention includes a substance having a conductivity at room temperature of from about 10 ³ to about 10 ^-10 S / cm, which is between the conductivity of metals and the conductivity of insulating materials. Specific examples of a semiconductor compound include:

Group IV elements such as silicon or germanium;

semiconductor compounds of groups II-VI, consisting of compounds of the elements of group II and group VI;

semiconductor compounds of groups III-V, consisting of compounds of elements of group III and group V;

semiconductor compounds of groups I-V, consisting of compounds of elements of group I and group V;

semiconductor compounds of groups I-VI, consisting of compounds of elements of group I and group VI;

semiconductor compounds of groups I-VII, consisting of compounds of elements of group I and group VII;

semiconductor compounds of groups II-IV, consisting of compounds of the elements of group II and group IV;

semiconductor compounds of groups II-V, consisting of compounds of the elements of group II and group V;

semiconductor compounds of groups II-VII, consisting of compounds of the elements of group II and group VII; and

semiconductor compounds of groups III-VI, consisting of compounds of elements of group III and group VI.

Group IV elements include carbon, tin, silicon carbide, and silicon-germanium in addition to the above silicon and germanium.

Semiconductor compounds of groups II-VI include a compound of at least one element selected from elements of group II, such as magnesium, calcium, strontium, barium, zinc, cadmium and mercury, and at least one element selected from elements of group VI such as oxygen, sulfur, selenium and tellurium. Specific examples include magnesium oxide, calcium oxide, strontium oxide, barium oxide, zinc oxide, zinc sulfide, barium sulfide, cadmium sulfide, magnesium sulfide, calcium sulfide, strontium sulfide, zinc selenide, barium selenide, cadmium selenide, magnesium selenide, calcium selenide, strontium selenide, barium selenide, zinc telluride, cadmium telluride, strontium telluride and barium telluride. Semiconductor compounds of groups II-VI can be compounds containing two or more of the elements of group II and / or elements of group VI, such as calcium strontium selenide sulfide, in addition to the above compounds containing each element in a 1: 1 ratio . From the point of view of the availability and stability of the compounds, zinc sulfide, cadmium sulfide, zinc selenide or cadmium selenide is preferred, and zinc sulfide is most preferred.

Semiconductor compounds of groups III-V include a compound of at least one element selected from elements of group III, such as boron, aluminum, gallium, indium and thallium, and at least one element selected from elements of group V, such as nitrogen , phosphorus, arsenic, antimony and bismuth. Specific examples include boron nitride, boron phosphide, boron arsenide, aluminum nitride, aluminum phosphide, aluminum arsenide, aluminum antimonide, gallium nitride, gallium phosphide, gallium arsenide, gallium antimonide, indium nitride, indium phosphide, indium arsenide and indium antimonide. Semiconductor compounds of groups III-V may be compounds containing two or more of the elements of group III and / or elements of group V, such as aluminum arsenide phosphide, in addition to the above compounds containing each element in a 1: 1 ratio.

Semiconductor compounds of groups IV include a compound of at least one element selected from elements of group I, such as sodium, potassium, cesium, lithium and rubidium, and at least one element selected from elements of group V, such as nitrogen, phosphorus , arsenic, antimony and bismuth. Specific examples include sodium antimonide, potassium antimonide, cesium antimonide, trilithium antimonide, trilithium bismuthide, trisodium antimonide, tricalium antimonide, tricezium antimonide, tricezium antimonide, trisidium bismuthide and trirubidium bismutide. Semiconductor compounds of groups IV can be compounds containing two or more of elements of group I and / or elements of group V, such as sodium potassium antimonide and cesium potassium antimonide, in addition to the above compounds containing each element in relation to 1: one.

Semiconductor compounds of groups I-VI include a compound of at least one element selected from elements of group I, such as copper and silver, and at least one element selected from elements of group VI, such as oxygen, sulfur, selenium and tellurium . Specific examples include copper oxide, dimedi oxide, dimedi sulfate, copper selenide, copper telluride, silver oxide, silver sulfide, silver selenide and silver telluride. Semiconductor compounds of groups I-VI can be compounds containing two or more of the elements of group I and / or elements of group VI, such as copper-silver oxide, in addition to the above compounds containing each element in a 1: 1 ratio.

Semiconductor compounds of groups I-VII include a compound of at least one element selected from elements of group I, such as copper and silver, and at least one element selected from elements of group VII, such as fluorine, chlorine, bromine and iodine . Specific examples include copper fluoride, copper chloride, copper bromide, copper iodide, silver fluoride, silver chloride, silver bromide and silver iodide. Semiconductor compounds of groups I-VII may be compounds containing two or more of the elements of group I and / or elements of group VII, in addition to the above compounds containing each element in a 1: 1 ratio.

Semiconductor compounds of groups II-IV include a compound of at least one element selected from elements of group II, such as magnesium, calcium, strontium and barium, and at least one element selected from elements of group IV, such as carbon, silicon , germanium, tin and lead. Specific examples include dimagnesium silicide, dimagnesium germide, dimagnesium stannide, dimagnesium plumbide, dicalcium silicide, dicalcium stannide, and dicalcium plumbide. Semiconductor compounds of groups II-IV can be compounds containing two or more of the elements of group II and / or elements of group IV, in addition to the above compounds containing each element in a 1: 1 ratio.

Semiconductor compounds of groups II-V include a compound of at least one element selected from elements of group II, such as magnesium, zinc, cadmium and mercury, and at least one element selected from elements of group V, such as arsenic, phosphorus and antimony. Specific examples include trimagnesium diarsenide, trincinc diphosphide, trincin diarsenide, tricadmium diphosphide, tricadmium diarsenide, tetracinc triantimonide, tetracadmium triantimonide, zinc antimonide, cadmium diphenoxide, cadmium dihydrogen phosphide, zinc cadmium di diphosphide, zinc di diphosphide, cadmium di diphosphide; Semiconductor compounds of groups II-V may be compounds containing two or more of the elements of group II and / or elements of group V, in addition to the above compounds containing each element in a 1: 1 ratio.

Semiconductor compounds of groups II-VII include a compound of at least one element selected from elements of group II, such as cadmium and mercury, and at least one element selected from elements of group VII, such as chlorine, bromine and iodine. Specific examples include cadmium chloride, cadmium bromide and cadmium iodide. Semiconductor compounds of groups II-VII may be compounds containing two or more of the elements of group II and / or elements of group VII, in addition to the above compounds containing each element in a 1: 1 ratio.

Semiconductor compounds of groups III-VI include a compound of at least one element selected from elements of group III, such as boron, aluminum, gallium, indium and thallium, and at least one element selected from elements of group VI, such as oxygen , sulfur, selenium and tellurium. Specific examples include gallium sulphide, gallium selenide, gallium telluride, indium sulphide, indium selenide, indium telluride, thallium sulphide, thallium telluride, thallium telluride, dihallium trisulide, dihallium trisulide, diindium triindulide, tridelenide, trilenide, trilenide, tridelenide, trilenide, tridelenide, trilenide, tridelenide, trilenide, tridelenide, tridelenide, trilenide. Semiconductor compounds of groups III-VI may be compounds containing two or more of the elements of group III and / or elements of group VI, in addition to the above compounds containing each element in a 1: 1 ratio.

Among these compounds, the use of a semiconductor compound of groups II-VI is preferred when producing visible light, since the band gap can vary over a wide range. The use of a semiconductor compound of groups III-V is also preferred, since the band gap is in the range of visible light.

Source of iridium:

The inorganic composition of the present invention is characterized in that it contains an iridium element, and a source of iridium is used to dope the iridium element. The iridium source may be formed solely from the iridium element or may be in the form of an oxide or sulfide, or may also be in the form of salts with other elements. Iridium compounds include iridium chloride, iridium sulfate, iridium nitrate, iridium nitrite, iridium oxide, ammonium hexachloridate (IV), hexachloridate (IV) n-hydrate, iridium (I) chlorocarbonyl bis (triphenylphosphine) and sodium- n-hydrate iridium (III). These iridium compounds can be used individually or in combination of two or more kinds.

Source of metal other than iridium:

An inorganic composition containing a metal source other than iridium can be used as a starting material to obtain a luminescent material by subjecting this inorganic composition to the alloying treatment described below. The metal source includes metal elements such as transition metals, including manganese, copper, silver, gold, and hafnium; and rare earths, including cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, tollium, ytterbium, lutetium and yttrium; and compounds of these metals, such as their sulfide, halide and oxide. These metal sources may be added to the inorganic composition as an activator mentioned below.

Activator:

The inorganic composition of the present invention, in particular, is characterized in that it contains an iridium element, and it can be converted into a luminescent material. This luminescent material can form an inorganic EL device that provides improved emission efficiency. In addition, the emission efficiency of the device can preferably be improved by the addition of an activator introduced into the semiconductor compound.

Activators preferably include transition metals, halogen or rare earth elements. Transition metals include manganese, copper, silver, gold and hafnium. Halogen includes chlorine and bromine. Rare earth elements include cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, tollium, ytterbium, lutetium and yttrium. They can be used individually or as a combination of two or more kinds, and can be used in the form of sulfide, halide, oxide, or the like.

Composition:

The inorganic composition before being converted to the inorganic composite of the present invention is not particularly limited, and includes a typical composition comprising:

from 80 to 95 parts by weight, preferably from 85 to 93 parts by weight of a semiconductor compound;

from 0.001 to 3 mass parts, preferably from 0.005 to 1 mass part of a source of iridium and / or a source of another metal; and

from 3 to 9 parts by weight, preferably from 4 to 7 parts by weight of activator.

(Inorganic composite and method for producing it)

In the first embodiment of the alloying treatment, the inorganic composition is subjected to explosion in an airtight vessel using a propelling and / or blasting explosive to form an inorganic composite (explosive method).

The propellant and / or blasting explosive used in the explosion is not particularly limited and includes nitroglycerin, TNT, nitrocellulose, nitrated pentaerythritol, graphite powder, gunpowder, smokeless powder and hexagen.

The amount of propellant and / or blasting explosive used in the explosive method varies depending on the equipment and type of explosive used, and, accordingly, it should not be determined generally, but usually it is from 1 to 10000 mass parts, but from the point of view economy and safety - from 2 to 9000 mass parts per 100 mass parts of inorganic composition.

The effect of the explosion on the inorganic composition varies depending on the amount of propellant and / or blasting explosive, equipment and type of explosive used, and accordingly it cannot be accurately determined, but usually the inorganic composition is exposed to a temperature of from 500 to 4000 ° C. and preferably from 600 to 3000 ° C.

In addition, the period of time during which the inorganic composition is exposed to high temperature cannot be precisely determined. It usually ranges from 1/10 of a second to 1/10000 of a second. Energy transfer by light can be assumed, and the irradiation time period is usually from 1/10 second to 1/10000 second.

In the explosive method of the present invention, the flight speed of the materials during the explosion (or the explosion speed) is also important. Depending on the magnitude of the speed of the explosion, the amount of impurities, such as carbon, in the inorganic composite produced by the explosion varies. Accordingly, the explosion speed is preferably from 100 m / s to 2000 m / s, and more preferably from 300 m / s to 1000 m / s.

In addition, we can assume the instantaneous pressure of the shock wave and an increase in temperature in this case. It can at least be assumed that the materials are exposed to a shock wave from 0.1 GPa to 50 GPa. You can also assume the heat released simultaneously with this shock wave, but the contribution of this heat cannot be accurately estimated, since only a general temperature rise can be observed due to the above temperature increase and temperature increase due to this heat.

The blasting method of the present invention can be carried out using a pressure-resistant reaction vessel, as shown in figure 1. In Fig. 1, reference numeral 1 denotes a pressure-resistant reaction vessel, reference numeral 2 denotes a reagent feed section, reference numeral 3 indicates a reaction vessel, reference numeral 4 indicates a heater, and reference numerals 5 and 6 indicate a power supply supplying power to the heating portion. The reaction is carried out in an airtight, pressure-resistant reaction vessel. Figure 2 is an enlargement of the reaction chamber of a high pressure resistant vessel. In this figure, reference numeral 7 denotes an explosive, and reference numeral 8 denotes an inorganic composition. An inorganic composite can be prepared using an apparatus for producing synthetic diamond using an explosion (for example, the apparatus disclosed in patent documents 5 and 6).

[patent document 5] Japanese patent publication Kokai Sho63-243205

[patent document 6] Japanese patent publication Kokai 2002-153747

In particular, the inorganic composition preferably contains a source of iridium as a source of metal. Although the inorganic composition contains a source of iridium, the method of introducing by doping a source of iridium into a semiconductor compound is not particularly limited. The alloying operation can be performed during the formation of a semiconductor compound, in particular a semiconductor compound II-VI, for example, during a liquid reduction reaction. The alloying operation can also be performed by heating or firing a semiconductor compound, in particular a semiconductor compound II-VI, and a source of iridium at 700 ° C. or more in an inert gas atmosphere or in a reducing gas atmosphere such as hydrogen sulfide. Can also be used a method of exposing an inorganic composition containing a semiconductor compound, in particular a semiconductor compound II-VI, and a source of iridium, the explosion of a propellant and / or blasting explosive (explosive method) in an airtight vessel.

The amount of iridium source and / or source of another metal introduced into the semiconductor compound during doping is not specifically limited, but it usually ranges from 1 × 10 ^-5 mass parts to 2 mass parts, and from the point of view of emission efficiency and economy, from 5 × 10 ^{- 5} mass parts to 0.5 mass parts per 100 mass parts of a semiconductor compound.

The amount of activator introduced during doping is not specifically limited, but usually, based on the total mass of metals, it is from 1 × 10 ^-3 mass parts to 10 mass parts, preferably from 1.5 × 10 ^-3 mass parts to 1 mass part, and in terms of emission efficiency, from 2 × 10 ^-3 mass parts to 0.5 mass parts, per 100 mass parts of the semiconductor compound.

In addition, the inorganic composition can be directly and simultaneously used to prepare a thin film during the formation of a film from a semiconductor compound II-VI, such as zinc sulfide, using a process such as electron beam sputtering or ion sputtering. In the case where the composition is made by subjecting a semiconductor compound, an iridium source and / or a source of another metal and an activator to a process such as electron beam sputtering or ion sputtering, the iridium source can be only an iridium element, and preferably is in the form of oxide, sulfide or a halide such as chloride or fluoride.

The fact that the iridium element and / or another metal element is introduced by doping into a semiconductor compound can be confirmed by measuring the quantum yield. Quantum yield means the ratio (number of photons emitted as a result of excitation by incident light) / (number of photons of incident light absorbed in a substance). Larger quantum yields mean higher doping effects, and this value can be measured with a fluorophotometer.

(Luminescent material)

In the present invention, the inorganic composite obtained by the explosive method can be converted into a luminescent material by heat treatment. The heat treatment can be carried out several times, and during the heat treatment can be carried out processing to control the size of the particles, such as grinding.

The heat treatment temperature varies depending on the type of inorganic composite used as the starting material, but usually it is from 500 to 1000 ° C, and preferably from 600 to 800 ° C. The heat treatment time period is not particularly limited, but it is usually from 1 to 20 hours, and preferably from 2 to 10 hours.

Before heat treatment, conductive compounds such as gallium oxide, zinc oxide, indium oxide or tin oxide, or semiconductor compounds such as gallium arsenide, indium arsenide, gallium phosphide or indium phosphide may be added to the inorganic composite.

As will be explained in detail below, the inorganic EL device can be formed from the luminescent material of the present invention by vapor deposition and the like. The vapor deposition method is not particularly limited and includes commonly used methods, such as an electron beam (electron beam) method, an ion sputtering method or an instant sputtering method.

(Dielectric)

In the case where an apparatus driven by alternating current is manufactured using the luminescent material of the present invention, a structure is used in which the light emitter layer is located between the dielectric layers, as shown in FIG. 3. A dielectric including known materials such as yttrium oxide, tantalum oxide, aluminum nitride, silicon nitride or barium titanate is used to form a thin film having a thickness of from about 0.1 μm to about 1 μm by ion sputtering, deposition from the gas phase, screen printing or the like.

Figure 3 is a sectional view of an example of an EL device using the luminescent material of the present invention. In this figure, reference numeral 18 denotes a rear electrode, reference numerals 19 and 21 indicate a dielectric, reference numeral 20 indicates a light emitter, reference numeral 22 indicates an electrode, reference numeral 23 indicates a transparent electrode, and reference numeral 24 denotes a glass substrate.

(Inorganic EL device)

As described above, electroluminescent devices (EL devices) are roughly classified into inorganic EL devices and organic EL devices because of the difference in materials of their light emitter. An inorganic EL device using inorganic material as a light emitter is characterized in that its light emission resource is greater than the light emission resource of an organic EL device using organic material as a light emitter. Therefore, the inorganic EL device has found practical application mainly for applications requiring high durability, such as display units for cash registers, vehicle monitors, and clock lights.

4 is a perspective view showing a key part of a typical configuration of a conventional inorganic EL device. The EL device 110 is a thin-film double insulated EL device that is formed by layering the lower electrode 112, the lower insulator layer 113, the light emitter layer 114, the upper insulator layer 115 and the upper electrode 120 in this order on a transparent substrate 111 having electrically insulating properties (see figure 3 of patent document 7).

[patent document 7] Japanese patent publication Kokai 2004-265740

As for the transparent substrate 111, a transparent substrate is used, such as blue sheet glass, commonly used in LCDs (liquid crystal displays) and DAP (plasma display panels). The bottom electrode 112 is typically formed of ITO (indium tin oxide) with a film thickness of about 0.1 to 1 μm. The upper electrode 120 is formed of a metal, such as Al. Layer 113 of the lower insulator and layer 115 of the upper insulator are thin films with a thickness of about 0.1 to 1 μm each, formed using a method such as ion sputtering or gas vapor deposition, which is usually made of Y ₂ O ₃ , Ta ₂ O ₅ , AlN, BaTiO ₃ and other materials. The light emitter layer 114 is usually formed from a light emitter containing a dopant, which should be the emission center, and its film thickness is usually from about 0.05 to 1 μm.

In a conventional EL device having such a configuration, when an alternating voltage or pulse voltage is supplied to the electrodes from the AC power source 121, the light emitter layer 114 gives electroluminescence, and the light exiting from it is removed from the side of the transparent substrate 111. When using an inorganic EL device as an indicator (display), the lower electrodes 112 and the upper electrodes 120 are made in the form of a strip pattern, with one side being for the row electrodes and the other side being for columns, and both of these types of electrodes are arranged so that their length directions are perpendicular to each other. In other words, the matrix electrodes are formed by electrodes 112 and electrodes 120, in which the sections of the light emitter layer at the intersection of the row and column electrodes are pixels, whereby when an alternating voltage or pulse voltage is selectively applied to it, a particular pixel shines and exits light is removed from the side of the transparent substrate 111.

However, the inorganic device described above requires an alternating voltage of 100 V or more to be supplied to it with a frequency in the range of several hundred Hz to tens of kHz, and it is less and less used in mobile devices such as notebook computers (laptops) and cell phones, which use rechargeable batteries, due to the fact that a device is required for converting direct current to alternating current, and for other reasons.

On the other hand, recently an organic EL cell has been noticed as an element capable of being driven by direct current, which is commercialized for applications in vehicles and cell phones that use rechargeable batteries. However, a fluorescent organic solid, which is the material of the light emitter layer of such an organic EL device, is unstable to moisture, oxygen, and other substances. Also, the characteristics of the electrode provided directly on the light emitter layer or through the hole injection layer or the electron injection layer tend to deteriorate due to oxidation. Thus, there is a problem in that when a conventional organic EL device is operated in the atmosphere, the emission characteristics quickly deteriorate. Various efforts have been made to deal with this problem (for example, see Patent Document 8), but the problem has not been fully resolved in terms of service life.

[patent document 8] Japanese patent publication Kokai Hei11-329718

Therefore, an inorganic EL device of direct current, capable of being driven by direct current, has been studied, taking into account the advantage of the feature of a long service life of inorganic EL (for example, see patent documents 9 and 10).

[patent document 9] Japanese patent publication Kokai Hei05-074572

[patent document 10] Japanese patent publication Kokai 2002-313568

However, in the case of conventional inorganic direct current EL devices, including those described in the aforementioned patent documents 9 and 10, for the most part there is no information regarding brightness, and the approach to realizing high brightness has not been carried out sufficiently.

Thus, there is a need for an inorganic EL device that can be driven by direct current and is applicable for high brightness applications such as lamps and light sources for use in mobile applications and the like.

The inorganic EL direct current device of the present invention is an inorganic EL device including at least layers of multiple electrodes and a light emitter layer made of an inorganic composition and provided between the electrode layers, and is characterized in that the brightness achieved upon reduction a direct current is 10000 cd / m ² or more. Here, the term "brightness" refers to the intensity with which light with a measured viewing angle of 1 degree, when observed from a direction normal to the light-emitting surface of an inorganic EL device, is measured with a telescopic brightness meter. In addition, in the inorganic EL device of the present invention, it is desirable that the layer thickness of the EL light emitter is 0.05 μm or more and 50 μm or less. Optimization of the thickness of the light emitter layer makes it possible to operate at low voltage and to prevent short circuits between the electrodes. In addition, in the inorganic EL device of the present invention, it is desirable that both surfaces between the above two electrode layers be made with different compositions. Changing and optimizing the composition of the surfaces between the electrodes allows you to increase performance, for example, to increase the emission efficiency and service life due to improved adhesion to the electrodes.

The inorganic EL element of the present embodiment includes, at least, a light emitter layer made of an inorganic composite between plural electrodes, wherein the attained brightness when activated DC is 10000 cd / m ² or more. In applications where high brightness is achieved brightness when activated DC is preferably 50000 cd / m ² or more, and more preferably - 100000 cd / ^m2 or more, more preferably - 300,000 cd / m ² or more, and more preferably - 500000 cd / ^m2 or more.

Typically, the light emitter layer is located between the first electrode and the second electrode. It is desirable that the first and second electrodes cover the entire front and rear main surfaces of the light emitter layer, whereby the entire light emitter layer is provided with highly efficient conductivity and a bright and uniform emission is achieved.

или менее, а более предпочтительно -

или менее.As for multiple electrodes “interlacing” the light emitter layer with each other, when a high brightness is realized, a large current flows, so that the surface resistance is preferably low in order to suppress heat generation due to the resistance value of the electrode layer. The surface resistance is preferably

or less, and more preferably

or less.

и коэффициент пропускания видимого света не ниже чем 90%. Желательно, чтобы он был образован из одного или двух или более слоев прозрачных проводящих материалов, таких как ITO, IZO (оксид индия-цинка), GZO (оксид галлия-цинка), ZnO (оксид цинка), AZO (оксид сурьмы-цинка) или ATO (оксид сурьмы-олова), или чтобы он был образован из тонкой пленки проводящих материалов, таких как серебро, толщина которой настолько мала, что свет может проходить через нее. Обычно проводящие материалы осаждают на прозрачной подложке, такой как стекло или сапфир, с помощью способа ионного распыления или тому подобного, формируя электродный слой.Multiple electrodes “interlacing” the light emitter layer between them may be the same or different from each other. In the case where the first electrode layer is a side of the surface of the light exit from the inorganic layer of the light emitter, the first electrode layer must be transparent to light. It is desirable that the first electrode layer has a surface resistance of not higher than

and the transmittance of visible light is not lower than 90%. It is desirable that it be formed from one or two or more layers of transparent conductive materials such as ITO, IZO (indium zinc oxide), GZO (gallium zinc oxide), ZnO (zinc oxide), AZO (antimony zinc) or ATO (antimony-tin oxide), or so that it is formed from a thin film of conductive materials, such as silver, whose thickness is so small that light can pass through it. Typically, conductive materials are deposited on a transparent substrate, such as glass or sapphire, by an ion sputtering method or the like, forming an electrode layer.

In the case of operation in the emission mode from the front side, in which light is emitted from the end portions of the light emitter layer instead of the light coming out through the first electrode layer covering the light emitting layer, or in the case of light coming out through the hole provided in the first electrode layer, the first electrode layer should not to be transparent. In these cases, an electrode may be formed using materials having reflective and conductive properties, such as silver, copper, and aluminum, in order to emit light with high efficiency through said end portions or said opening.

A method of forming an electrode layer, which should not be transparent, is not limited specifically. For example, there is a method of forming an electrode by deposition of a conventional metal, such as silver or aluminum, by a method of deposition from a gas phase or other methods, and when forming an electrode from a back side substrate, a method of manufacturing a conductive flat substrate, such as a conductive silicon substrate, as electrode.

The light emitter layer must be formed of a luminescent material made of an inorganic composite capable of emitting light with high brightness. The method for producing this material is not limited specifically, but includes a method that leads to the presence of a special structure in the inorganic composite, for example, by exposing the inorganic composite to an explosion. Preferably, this material is characterized in that it emits light as a result of photoluminescence (PL). If the thickness of the light emitter layer is too large, then the voltage between the electrodes increases so as to obtain the electric field strength required to emit light, so that from the point of view of applying a lower voltage and productivity, its thickness is preferably 50 μm or less, more preferably 20 μm or less, and more preferably 5 μm or less. If the thickness of the light emitter layer is too small, the electrode layers on both sides of the EL layer of the light emitter tend to short-circuit, so from the point of view of preventing this, its thickness is preferably 0.05 μm or more, and more preferably 0.1 μm or more.

The deposition method used herein includes a vapor deposition method, which is a physical vapor deposition method in a vacuum, and methods for depositing inorganic material such as ion sputtering and ion deposition. The material used for the inorganic EL light emitter layer to achieve high brightness is substantially stable, but has a high melting point, so it is preferable to use a deposition method, such as electron beam (EB) vapor deposition, capable of vaporizing a material having a high melting point, and also capable of suppressing pollution from a material-holding crucible and the like, or ion sputtering when an inorganic material is a target.

In addition, a method for changing the compositions of two surfaces between a light emitter layer and electrodes includes, for example, a method in which a second component is installed in another gas deposition source or target, changing the film formation rate of the second component. It is also permissible to install two different types of compositions in separate sources of deposition from the gas phase or target, gradually changing the rate of formation of their films depending on the course of deposition or changing the film-forming target from the first material to the second material during deposition. In the same manner as described above, a layer of three or more types of compositions may be formed. It is advisable to use a method of gradually changing the rates of film formation or a method of forming a layer of three or more types of compositions, since these methods protect against delamination. In addition, in the same manner as described above, the compositions of both main surfaces of the light emitting layer are made identical to each other, and the composition between the main surfaces is made different from the compositions of the main surfaces, so that a multilayer structure can be formed. Since such a layered structure makes it possible to provide a composition suitable for increasing the adhesion of the electrodes to the main surface and to provide a composition suitable for increasing the brightness of light emission between the main surfaces, this structure is advantageous, in particular, in the case where two electrodes “interlacing” between a light-emitting layer is made of the same material.

With regard to improving adhesion between the light emitter layer and the electrode layers, there is a method of mixing other metals with the luminescent material in order to improve the affinity for the electrodes.

Further, in order to improve brightness, a layer comprising a semiconductor compound such as gallium arsenide or indium phosphide may be provided between the light emitter layer and the electrode layers.

EXAMPLES

The present invention will be explained using the following examples. The present invention should not be limited to these examples.

Comparative Example 1-1: Preparation of Sample A

100 g of zinc sulfide, 0.5 g of zinc oxide, 0.5 g of copper (II) sulfate, 3 g of barium fluoride, 3 g of magnesium chloride and 2 g of sodium chloride were weighed and then placed in an aluminum oxide crucible. The crucible was installed in a vacuum kiln, the inner space of which was evacuated and then filled with nitrogen. The crucible was fired for 6 hours at 1000 ° C. After cooling, the materials were washed with distilled water to remove unnecessary salts and dried. The resulting calcined mass was crushed using a sorting mill to obtain a powder having a particle size of 5 to 20 μm.

The powder was then placed in an alumina crucible. The crucible was installed in a vacuum kiln, the inner space of which was evacuated and then filled with nitrogen. The crucible was fired for about 8 hours at about 700 ° C. under a nitrogen gas atmosphere. The product was washed with glacial acetic acid to remove excess compounds, unnecessary salts and impurities, and washed with distilled water. Then the product was filtered off, dried at about 180 ° C and cooled to obtain a luminescent material (sample A).

Example 1-1: Preparation of Sample B

100 g of zinc sulfide, 0.5 g of zinc oxide, 0.27 g of manganese (II) sulfate, 3 g of barium fluoride, 3 g of magnesium chloride, 2 g of sodium chloride and 0.012 g of iridium (III) chloride were weighed and then placed in a crucible from aluminum oxide. The crucible was installed in a vacuum kiln, the inner space of which was evacuated and then filled with nitrogen. The crucible was fired for 6 hours at 1000 ° C. After cooling, the materials were washed with distilled water to remove flux and dried. The resulting calcined mass was crushed using a sorting mill to obtain a powder having a particle size of 5 to 20 μm.

The powder was placed in an alumina crucible. The crucible was installed in a vacuum kiln, the inner space of which was evacuated and then filled with nitrogen. The crucible was fired for about 8 hours at about 700 ° C. under a nitrogen gas atmosphere. The product was washed with glacial acetic acid to remove excess compounds, flux and impurities, and washed with distilled water. Then the product was filtered off, dried at about 180 ° C and cooled to obtain a luminescent material (sample B).

Example 1-2: Preparation of Sample C

100 g of zinc sulfide, 0.5 g of copper (II) sulfate, 0.5 g of zinc oxide, 3 g of barium fluoride, 3 g of magnesium chloride and 2 g of sodium chloride were mixed and used as the inorganic composition 8 shown in FIG. 2 and placed in the reaction chamber 2 shown in FIG. 2 of the reaction vessel 1 shown in FIG. 1. Then, 32 g of TNT (the amount calculated for 500 atm.) Was added as explosive 7, and the pressure-resistant reaction vessel 1 was sealed. After reducing the pressure to 0.01 mm Hg a current was passed through heater 4, heating the reaction chamber 2 to a temperature of 450 ° C, causing a TNT explosion, thereby forming a calcined mass.

The calcined mass was then removed from the reaction vessel 1, cooled, washed with distilled water, removing the flux, and dried. The resulting calcined mass was ground in a sorting mill to obtain a powder having a particle size of 5 to 20 μm. The obtained powder was placed in a quartz tube reaction vessel of a cylindrical electric furnace and burned in this quartz tube in a nitrogen atmosphere at a temperature of about 700 ° C for about 8 hours. The resulting product was washed with glacial acetic acid to remove excess compounds, flux and impurities, and washed with distilled water. Then the product was filtered off, dried at about 180 ° C, cooled and sieved in a sorting machine, obtaining a luminescent material (sample C).

Example 1-3: preparation of sample D

100 g of zinc sulfide, 0.5 g of zinc oxide, 0.27 g of manganese (II) sulfate, 3 g of barium fluoride, 3 g of magnesium chloride, 0.012 g of iridium (III) chloride and 2 g of sodium chloride were mixed and used as inorganic composition 8 shown in figure 2, and was placed in shown in figure 2, the reaction chamber 2 of the reaction vessel 1, shown in figure 1. Then, 32 g of TNT (the amount calculated for 500 atm.) Was added as explosive 7, and the pressure-resistant reaction vessel 1 was sealed. After reducing the pressure to 0.01 mm Hg a current was passed through heater 4, heating the reaction chamber 2 to a temperature of 450 ° C, causing a TNT explosion, thereby forming a calcined mass.

The calcined mass was then removed from the reaction vessel 1, cooled, washed with distilled water, removing the flux, and dried. The resulting calcined mass was ground in a sorting mill to obtain a powder having a particle size of 5 to 20 μm. The obtained powder was placed in a quartz tube reaction vessel of a cylindrical electric furnace and burned in this quartz tube in a nitrogen atmosphere at a temperature of about 700 ° C for about 8 hours. The resulting product was washed with glacial acetic acid to remove excess compounds, flux and impurities, and washed with distilled water. Then the product was filtered off, dried at about 180 ° C, cooled and sieved in a sorting machine to obtain a luminescent material (sample D).

Brightness measurement

The luminescent materials obtained in comparative example 1-1 and examples 1-1, 1-2 and 1-3 were sorted to obtain luminescent body particles containing 80% or more of particles having a size of 12 to 18 μm. The luminescent body paste was prepared by dispersing the luminescent body particles in a binder (7155, manufactured by DuPont) so that the particle concentration was 70% by weight. Then, a barium titanate paste (7153, manufactured by DuPont), the aforementioned luminescent body paste and barium titanate paste (7153, manufactured by DuPont) were applied to the electrode consisting of a glass substrate 24 with an ITO film 23 in this order using a silk screen, forming a layer 21 barium titanate, light emitting layer 20 and barium titanate layer 19. Then, a silver paste was applied to the barium titanate layer 19 to form an electrode 18. Next, a silver paste was applied to the periphery of the ITO film 23 to form an auxiliary electrode 22. As a result of the above procedure, the inorganic EL device shown in FIG. 3 was obtained. An alternating voltage of eight kHz was applied between the electrode 18 and the auxiliary electrode 22. The voltage was 280 V. The brightness shown in table 1 represents the values measured after 0 hours, 24 hours and 100 hours.

The luminescent materials obtained in examples 1-1, 1-2 and 1-3 show a brightness that remained at 65% or more of the original brightness even after 100 hours, while in the luminescent materials of comparative example 1-1, the brightness decreased to less than half of the original brightness after 100 hours.

Table 1 Luminescent material brightness (cd / m ² ) source after 24 hours after 100 hours Comparative Example 1-1 Sample A 485 322 221 Example 1-1 Sample B 612 499 403 Example 1-2 Sample C 1021 877 851 Example 1-3 Sample D 1202 1065 1026

Example 2-1

100 g of zinc sulfide, 0.5 g of zinc oxide, 0.27 g of manganese (II) sulfate, 3 g of barium fluoride, 3 g of magnesium chloride, 2 g of sodium chloride and 0.012 g of iridium (III) chloride were weighed and then placed in a crucible from aluminum oxide. The crucible was installed in a vacuum kiln, the inner space of which was evacuated and then filled with nitrogen. The crucible was fired for 6 hours at 1000 ° C. After cooling, the materials were washed with distilled water to remove unnecessary salts and dried. The resulting calcined mass was crushed using a sorting mill to obtain a powder having a particle size of 5 to 20 μm.

The obtained powder was placed in a quartz tube reaction vessel of a cylindrical electric furnace and burned in this quartz tube in a nitrogen atmosphere at a temperature of about 700 ° C for about 8 hours. The resulting product was washed with glacial acetic acid to remove excess compounds, unnecessary salts and impurities, and washed with distilled water. Then the product was filtered off, dried at about 180 ° C, and cooled.

The quantum yield of the resulting light emitter was measured using an FP-6500 fluorophotometer manufactured by Nippon Bunkou Co. and equipped with a fluorescent integrating spherical assembly and a program for calculating the quantum yield of solid, under conditions of measurement of a 1 mm slotted attachment, an excitation wavelength of 350 nm, an excitation bandwidth of 5 nm, and a fluorescence bandwidth of 1 nm. The results are shown in table 2.

Comparative Example 2-1

Fluorescent body powder was obtained in the same manner as in Example 2-1, except that iridium chloride was not used. The quantum yield of the obtained fluorescent body is shown in table 2.

Example 2-2

Fluorescence body powder was obtained in the same manner as in Example 2-1, except that 0.27 g of copper (II) sulfate was used instead of manganese sulfate. The quantum yield of the obtained fluorescent body is shown in table 2.

Comparative Example 2-2

Fluorescent body powder was obtained in the same manner as in Example 2-2, except that iridium chloride was not used. The quantum yield of the obtained fluorescent body is shown in table 2.

Example 2-3

Fluorescent body powder was obtained in the same manner as in Example 2-1, except that 0.5 g of zinc selenide was used instead of zinc oxide. The quantum yield of the obtained fluorescent body is shown in table 2.

Comparative Example 2-3

Fluorescent body powder was obtained in the same manner as in Example 2-3, except that iridium chloride was not used. The quantum yield of the obtained fluorescent body is shown in table 2.

Example 2-4

100 g of strontium sulfide, 0.3 g of cerium fluoride, 0.012 g of iridium (III) chloride, 0.3 g of potassium chloride and 5 g of sulfur were mixed and this mixture was heated in 100% H ₂ S at 500 ° C for 6 hours and then at 200 ° C for 7 hours, forming a fluorescent body powder. The quantum yield of the obtained fluorescent body is shown in table 2.

Comparative Example 2-4

Fluorescent body powder was obtained in the same manner as in Example 2-4, except that iridium chloride was not used. The quantum yield of the obtained fluorescent body is shown in table 2.

table 2 luminescence wavelength (nm) quantum yield (%) Example 2-1 567 56 Comparative Example 2-1 569 32 Example 2-2 463 62 Comparative Example 2-2 467 31 Example 2-3 571 59 Comparative Example 2-3 570 37 Example 2-4 477 43 Comparative Example 2-4 471 22

Preparation of the luminescent material used in examples 3-1 and 3-2

An amount of 100 g of zinc sulfide was mixed with 0.27 g of manganese (II) sulfate, 0.5 g of zinc oxide, 3 g of barium fluoride, 3 g of magnesium chloride, 0.012 g of iridium (III) chloride and 2 g of sodium chloride and mixed materials were placed into the reaction chamber of a vessel resistant to high pressure, followed by the addition of 32 g of trinitrotoluene. The reaction vessel was sealed, reducing the pressure therein to 0.01 mm Hg, and the reaction chamber was heated to about 450 ° C., causing an explosion. After confirming that an explosive reaction was carried out in the vessel, the reaction chamber was cooled and the crude product was recovered. It was placed in water and stirred, and then the suspended solids were recovered. The water contained was removed, and then the product was dried at room temperature to obtain 15 g of a dried product. The dried product was ground using a mill, then 5 mg of gallium arsenide was added to it and mixed. The mixture was heated at a temperature of 700 ° C in a nitrogen atmosphere for 8 hours, obtaining a crude luminescent body. Glacial acetic acid was added to the crude luminescent body, mixed, and then the dissolved materials were removed. Then distilled water was added and the mixture was stirred while washing the product, and then the water was removed. The resulting product was crushed and turned into powder, forcing it to serve as a luminescent material.

Using the luminescent material obtained by the above procedure, the circuit of the EL device shown in FIG. 5 and consisting of a first electrode layer (substrate) 101, a first light emitter layer 102, a second light emitter layer 103, a second electrode layer (silver thin film) 104 and a direct current power source 109, manufactured in accordance with the procedures explained below.

Example 3-1: obtaining an EL device

A 200 nm thick ITO film was formed on a transparent substrate 101 of Corning glass (# 1737) using an ion sputtering method, providing a first electrode layer 101.

Then, the luminescent material provided from the first source of deposition from the gas phase and selenium provided from the second source of deposition from the gas phase were deposited by means of an electron deposition unit from the gas phase through a 2 × 2 mm metal mask on the above glass substrate with an ITO film. The luminescent material was provided at a constant deposition rate from the first gas phase deposition source, and selenium was provided from the second gas deposition source at a certain deposition rate, and these two materials were deposited on the above glass substrate with an ITO film at the same time, so that the mass fraction of selenium was 0.5% or less in the first half of the precipitation process, and in the last half of the precipitation process, the mass fraction of selenium was approximately 1%. The degree of vacuum during the deposition process was 1 × 10 ⁻⁴ Pa or less. The temperature of the glass substrate during the deposition process was approximately 300 ° C. This process resulted in a light emitter layer having a two-layer structure from a first layer 102 having a lower proportion of selenium in its composition and a second layer 103 having a higher proportion of selenium in its composition. The thickness of the first layer was approximately 1 μm; the thickness of the second layer was about 1 μm; the total thickness of the bilayer structure was approximately 2 μm.

The substrate on which the light-emitting layer was formed was exposed to air and then subjected to heat treatment at 650 ° C. for 60 minutes in a nitrogen atmosphere to improve crystallinity. After heat treatment on the light-emitting layer, using a resistance-heated vapor deposition apparatus, a silver film about 200 nm thick was formed as the second electrode layer 104. During the formation of the silver film, the vacuum was 7 × 10 ⁻⁴ Pa and the substrate was not heated. This process led to the production of the EL device shown in FIG. 5 and having a light emitting side on the first electrode layer 101.

Example 3-2: obtaining an EL device

Luminescent material was deposited on the silicon single-crystal substrate as the first electrode layer by means of an electron deposition unit from the gas phase through a 2 × 2 mm metal mask where the luminescent part was to be formed. When a light emitter layer was formed, the above luminescent material was provided from the first gas phase deposition source, and selenium was provided from the second gas phase deposition source, and these two materials were deposited on a silicon single crystal substrate through a 2 × 2 mm metal mask at the same time, so that the mass fraction of selenium was 0.5% or less in the first half of the precipitation process, and in the last half of the precipitation process, the mass fraction of selenium was approximately 1%. The degree of vacuum during the deposition process was 1 × 10 ⁻⁴ Pa or less. The temperature of the glass substrate during the deposition process was approximately 300 ° C. This process resulted in a light emitter layer having a two-layer structure from a first layer 102 having a lower proportion of selenium in its composition and a second layer 103 having a higher proportion of selenium in its composition. The thickness of the first layer was approximately 1 μm; the thickness of the second layer was about 1 μm; the total thickness of the bilayer structure was approximately 2 μm.

Then, using another source of vapor deposition inside the same chamber, a silver layer with a thickness of less than 0.1 μm was applied, causing it to serve as the second electrode layer 104.

The above process led to the production of the EL device shown in FIG. 5 and having a light emitting side on the second electrode layer 104.

Evaluation of the EL device obtained in examples 3-1 and 3-2

The first electrode layer of the obtained EL device from examples 3-1 and 3-2 was connected to the negative electrode of the DC power source, and the second electrode layer was connected to the positive electrode of the DC power source. The achieved brightness was determined. When a voltage is gradually increased, the brightness achieved 375,000 cd / ^m2 at 5 V.

Reference example

Luminescent materials were obtained in the same manner as in examples 3-1 and 3-2, except that as a doping method in this process for the luminescent materials used in examples 3-1 and 3-2, instead of an explosive method, the process was used heating inorganic compositions at 1200 ° C for 5 hours. Using the obtained luminescent materials, EL devices were obtained in the same manner as in examples 3-1 and 3-2. The attained brightness of the obtained EL devices was only 6000 cd / m ^2.

Industrial applicability

The present invention provides a method for producing an inorganic composite. The luminescent material obtained by heat treatment of an inorganic composite obtained using the method of the present invention has an improved brightness as well as an improved service life, and accordingly it can be preferably used for an inorganic device and is industrially applicable.

The inorganic composition of the present invention leads to a luminescent material to form an excellent light emitter without involving a powder formation step causing a new problem, such as agglomeration, and accordingly it is industrially applicable. An inorganic EL device made by using the inorganic composition of the present invention as a starting material for producing a luminescent material, provides effective light emission of the composition of its materials.

Claims (12)

1. A method of obtaining an inorganic composite to obtain an electroluminescent material, and this method includes exposing the inorganic composition, mainly containing a semiconductor compound, to explode with a propellant explosive and / or blasting explosive in an airtight vessel,
wherein the inorganic composition contains:
from 80 to 95 parts by weight semiconductor compounds;
from 0.001 to 3 parts by weight a metal source, wherein said metal source is an iridium source or a combination of an iridium source and at least one metal source other than iridium; and
from 3 to 9 parts by weight activator. 2. The method according to claim 1, wherein the inorganic composition contains an iridium element. 3. An inorganic composition suitable for use as a starting material for producing an electroluminescent material, comprising a semiconductor compound as a main component and an iridium element, wherein the semiconductor compound is selected from the group consisting of semiconductor compounds consisting of elements of group II and group VI;
wherein the inorganic composition contains:
from 80 to 95 parts by weight semiconductor compounds;
from 0.001 to 3 parts by weight combinations of a source of iridium and at least one metal source other than iridium; and
from 3 to 9 parts by weight activator. 4. The inorganic composition according to claim 3, wherein the semiconductor compound is a semiconductor compound consisting of elements of group II and group VI. 5. A method of obtaining an inorganic composite to obtain an electroluminescent material, and this method includes heat treatment of the inorganic composition according to claim 3 or 4. 6. Inorganic composite to obtain an electroluminescent material, which is obtained from the inorganic composition according to claim 3 or 4 by the method according to claim 1 or 5. 7. A method of producing an electroluminescent material, moreover, this method includes the heat treatment of an inorganic composite obtained by the method according to claim 1 or 5. 8. The electroluminescent material obtained by the method according to claim 7. 9. Inorganic EL device using an electroluminescent material according to claim 8. 10. Inorganic EL device containing:
at least two electrodes; and
a light emitter layer consisting of an electroluminescent material according to claim 8 and provided between the electrodes;
wherein the brightness of the device attained during actuation of the constant current is 10000 cd / m ² or more. 11. The inorganic EL device of claim 10, wherein the thickness of the light emitter layer is from 0.05 μm to 100 μm. 12. The inorganic EL device of claim 10 or 11, wherein the light emitting layer comprises a plurality of light emitting layers having different compositions.

Images