JP2008274117A - Process for preparing phosphor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a process for preparing a phosphor which can economically advantageously prepare a phosphor. <P>SOLUTION: The process for preparing a phosphor comprises introducing a mixture comprising a group II-VI compound semiconductor and a salt containing a doping element together with a carrier gas into a flame whose temperature is controlled to 1,700 to 2,700°C. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a phosphor.

  Inorganic compositions mainly composed of compound semiconductors are used in the fields of light emitting materials such as fluorescence and phosphorescence, and phosphorescent materials. Some of these have the property of emitting light by electrical energy, and are used as light sources, and are partially used for applications such as display. However, currently known materials have insufficient light conversion efficiency of electric energy, and thus have problems such as heat generation and power consumption, and are limited in application.

These materials are generally manufactured by doping a base compound semiconductor with a trace amount of metal elements by a method such as firing (Patent Document 1). Moreover, when producing | generating a compound semiconductor by a liquid phase reaction, it manufactures by the method of doping a trace amount metal element simultaneously (patent document 2). Furthermore, a method for improving the efficiency of the phosphor obtained by these methods through a complicated process is known (Patent Document 3). As a simple method, a method of doping a trace amount of metal element by spraying an aqueous solution in which a metal salt is dissolved directly into a flame is also known (Patent Document 4).
Japanese Patent Laid-Open No. 8-183954 JP 2003-73119 A JP 11-193378 A JP 2005-239960 A

  However, the phosphors obtained by these methods do not have sufficient light emission luminance or energy efficiency, and thus require more complicated processing and are not economically advantageous. Accordingly, an object of the present invention is to provide an economically advantageous method for producing a phosphor.

  The present inventors diligently studied, mixed a group II-VI compound semiconductor and a salt containing an element to be doped, introduced the mixture into a flame together with a carrier gas, and controlled the temperature of the flame to control the II-VI in the flame. It has been found that the above object can be achieved by doping in a group compound semiconductor, and the present invention has been completed.

  That is, the present invention introduces a mixture containing a group II-VI compound semiconductor and a salt containing a doping element into a flame whose temperature is controlled at 1700 ° C. to 2700 ° C. together with a carrier gas. It is.

  According to the phosphor manufacturing method of the present invention, an energy efficient phosphor can be manufactured economically and advantageously. The present invention is based on the novel finding that a phosphor can be produced by a very simple method of allowing a flame to pass through a preliminarily crystallized II-VI group compound semiconductor and a dopant compound under predetermined conditions. The invention has the advantage that the phosphor can be produced without going through the firing step after the flame treatment. Therefore, the present invention is extremely useful industrially.

  The II-VI group compound semiconductor used in the present invention is not particularly limited. For example, zinc sulfide, cadmium sulfide, zinc selenide, cadmium selenide, or the like may be used. These may be used alone or in combination. The crystal structure constituting the II-VI group compound semiconductor is not particularly limited, and may be either a hexagonal crystal or a cubic crystal, or a hybrid thereof.

  In the present invention, the element doped in the II-VI group compound semiconductor is not particularly limited, for example, transition metals such as copper, silver, manganese, iridium, and rare earth elements such as cerium, praseodymium, samarium, and europium. Can be mentioned. These may be used alone or in combination. In particular, in consideration of the phosphor characteristics, it is preferable to add an element that forms a directly excited phosphor such as manganese or praseodymium.

  The kind of the salt containing the doping element is not particularly limited, but is a mineral salt such as hydrochloride, nitrate or sulfate, an organic acid salt such as acetate or oxalate, and an organic acid salt such as acetylacetonate. A metal complex etc. can be mentioned. In view of availability, solubility in water, etc., it is preferable to use hydrochloride, nitrate, or acetate.

  The amount of the element to be doped is not particularly limited, but if it is too much, it is not economical and may cause concentration quenching, and if it is too low, it is sufficient to extract high fluorescence efficiency. In general, it is preferably 5 to 5000 ppm and more preferably 10 to 1000 ppm in the obtained phosphor by ICP emission analysis.

  In the present invention, an inorganic composition of a salt containing a II-VI group compound semiconductor and a doping element is directly introduced into a flame to produce fine particles in the flame. In such a method for producing phosphor fine particles according to the present invention, the II-VI group compound semiconductor may be heated only once in a flame. According to the method of the present invention, since the II-VI group compound semiconductor is directly introduced into the flame to generate the fine particles by heating, the fine particles can be generated at a high temperature unlike conventional methods. Good fine particles can be produced.

  In order to generate a flame, for example, fuel gas such as methane, propane, ethylene, propylene, acetylene and oxygen are used. The material mixture of the II-VI group compound semiconductor and the salt containing the doping element is introduced into the flame together with the carrier gas. The carrier gas is preferably a neutral or reducing gas such as nitrogen, argon, or hydrogen.

  Air or oxygen necessary for combustion may be supplied alone, but air or oxygen may be supplied as a carrier gas, or air or oxygen may be supplied together with the above carrier gas. In the present invention, the flame temperature is controlled to 1700 ° C. to 2700 ° C. by controlling the flow rate of the fuel gas.

  In the present invention, a mixture of a II-VI group compound semiconductor and a salt of a doping element is introduced into the flame together with the carrier gas. The introduction rate depends on the amount of the carrier gas, but is usually 0.1 g to 500 g / Minutes are preferable, and 1 to 100 g / min is more preferable in consideration of operability and safety.

  The mixture of the II-VI compound semiconductor introduced into the flame and the salt of the doping element becomes an II-VI compound semiconductor doped with the element in the flame, and is released out of the flame. The atmosphere of the release destination is not particularly limited, but it can be released into an inert gas such as nitrogen or argon in order to prevent an excessive reaction such as oxidation by contact with air. .

  The obtained fine particles can be collected by being sprayed on a metal plate or the like and collected as a coated material, or collected by a filter-like material. In order to cool more rapidly and suppress aggregation of fine particles, it is preferable to cool the fine particles by bringing the obtained fine particles into contact with a metal plate maintained at a low temperature.

  The formation of the phosphor can be confirmed by measuring the quantum efficiency. Quantum efficiency is the ratio between the number of photons emitted by excitation by incident light and the number of photons of incident light absorbed by the material, and the larger this value, the higher the doping effect. Quantum efficiency can be measured with a spectrofluorometer. The obtained fine particles can be used as phosphors as they are.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.
Example 1
1.619 g of manganese nitrate (II) was mixed with 300 g of zinc sulfide (RAK-N) manufactured by Sakai Chemical Co., Ltd., and mixed with a ball mill for 1 hour to obtain a mixture of a II-VI group compound semiconductor and a metal salt. This powder mixture was introduced into a flame at 2000 ° C. using a Terodyne 2000 (manufactured by Nippon Yutec Co., Ltd.) thermal spraying apparatus using propane as the combustion gas and oxygen as the carrier gas.

  After adjusting the gas flow rate and adjusting the flame length to 200 mm, the powder mixture was introduced at 10 g / min, released into a chamber filled with nitrogen gas, and naturally cooled. The discharge was continued for 10 minutes, and 68 g of the deposited fine particle powder was recovered. Table 1 shows the Mn doping amount of the obtained phosphor by ICP emission analysis, and Table 2 shows the emission wavelength and quantum efficiency of the phosphor.

Example 2
In Example 1, except that the amount of manganese nitrate used was 8.12 g, the same procedure as in Example 1 was performed to recover 71 g of fine particle powder. Table 1 shows the Mn doping amount of the obtained phosphor by ICP emission analysis, and Table 2 shows the emission wavelength and quantum efficiency of the phosphor.

Example 3
In Example 1, except that the manganese nitrate was changed to 0.92 g of praseodymium acetate, the same procedure as in Example 1 was carried out to recover 66 g of fine particle powder. Table 1 shows the amount of praseodymium doping by ICP emission analysis of the obtained phosphor, and Table 2 shows the emission wavelength and quantum efficiency of the phosphor.

Example 4
In Example 1, except that the amount of oxygen was adjusted and the powder was introduced into a flame at 1800 ° C., it was carried out in the same manner as in Example 1, and 77 g of fine particle powder was recovered. Table 1 shows the Mn doping amount of the obtained phosphor by ICP emission analysis, and Table 2 shows the emission wavelength and quantum efficiency of the phosphor.

Example 5
In Example 1, except that the amount of oxygen was adjusted and the powder was introduced into a flame at 2600 ° C., the same operation as in Example 1 was carried out to recover 49 g of fine particle powder. Table 1 shows the Mn doping amount of the obtained phosphor by ICP emission analysis, and Table 2 shows the emission wavelength and quantum efficiency of the phosphor.

Comparative Example 1
In Example 1, except that the amount of oxygen was adjusted and the powder was introduced into a 2800 ° C. flame, the same procedure as in Example 1 was carried out. The powder was diffused, and the powder recovery rate was 0%. .

Comparative Example 2
In Example 1, except that the amount of oxygen was adjusted and the powder was introduced into a flame at 1500 ° C., the same operation as in Example 1 was carried out to recover 82 g of fine particle powder. Table 1 shows the Mn doping amount of the obtained phosphor by ICP emission analysis, and Table 2 shows the emission wavelength and quantum efficiency of the phosphor.

The measurement conditions of the spectrofluorometer were as follows.
Measuring device: FP-6500 manufactured by JASCO
Excitation wavelength: 350 nm
Excitation bandwidth: 5 nm
Software: Spectra Manager for Windows (registered trademark) 95 / NT Ver1.00.00 2005 manufactured by JASCO Corporation

  Although the quantum efficiency of the phosphor is preferably 20% or more, the results of the above examples show that the phosphors obtained by the method of the present invention all have a quantum efficiency of 20% or more.

  According to the method for producing a phosphor of the present invention, the phosphor can be advantageously produced economically, which is industrially useful.

Claims (1)

  A method for producing a phosphor, comprising introducing a mixture containing a group II-VI compound semiconductor and a salt containing a doping element into a flame controlled with a temperature of 1700 ° C. to 2700 ° C. together with a carrier gas.