JP2016017125A - Manganese-doped spinel type red fluophor and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oxide fluorescent emitter fluorescently emitting red, and a method for producing the same.SOLUTION: Provided is an oxide fluorescent emitter being an ABOspinel type oxide in which an A site element being Mg, the B site element being Al or Ga, and Mn is doped, and including Mg of an excessive amount exceeding a stoichiometric ratio, in which the excessive amount of Mg in the case the B site element being Al lies in the range of 0.1 to 0.7 by a stoichiometric ratio to A in the ABOspinel type oxide and the dope amount of Mn lies in the range of 0.05 to 0.2 mol% to the ABOspinel type oxide, and the excessive amount of Mg in the case the B site element being Ga lies in the range of 0.1 to 0.9 by a stoichiometric ratio to A in the ABOspinel type oxide and the dope amount of Mn lies in the range of 0.025 to 0.2 mol% to the ABOspinel type oxide.SELECTED DRAWING: None

Description

  The present invention relates to an oxide fluorescent substance that emits red light and a method for producing the same.

Spinel is derived from the mineral name of MgAl ₂ O ₄ (Japanese name: spinel), and its structure is based on a diamond structure, and its general chemical formula is represented as AB ₂ X ₄ . In this chemical formula, the A site forms an isolated tetrahedron surrounded by four X site anions (eg, oxide ions), and the B site is an octahedron surrounded by six anions and sharing sides. It is represented by the structure formed.

For example, the following prior art is known as a study on the fluorescence emission of a spinel oxide. For example, as a spinel type oxide emitting blue light, Non-Patent Document 1 reports spinel type ZnGa ₂ O ₄ . Further, as a spinel oxide that emits red light, Non-Patent Document 2 proposes calcium aluminate doped with manganese, and it is reported that the amount of manganese added affects the luminance of emitted light.

Patent Document 1 proposes a transition metal-doped spinel type MgGa ₂ O ₄ (magnesium gallate) phosphor. This phosphor is a phosphor in which spinel-type MgGa ₂ O ₄ is used as a host crystal, and this host crystal is doped with Mn as a transition metal as a transition metal, and emits green light having a peak at 508 nm and 674 nm by band edge excitation. It emits red light having a peak. Patent Document 2 proposes a transition metal-doped spinel type MgAl ₂ O ₄ phosphor. This phosphor is formed by pressing a mixed raw material mixed so that the amount of Mg is several percent excess with respect to the amount of Al of the Al raw material to form a raw material rod, which is single-crystallized by floating zone melting. It is to be obtained. The amount of Mn doping is preferably in the range of 0.003 ≦ x ≦ 0.01 in the composition formula Mg _1-x Mn _x AlO ₄ .

Kim, J.S., “Color variation of ZnGa2O4 phosphor by reduction-oxidation processes”, Applied Physics Letters, 82 (13), p.2029-2031 (2003). Koji Inoue, Shinya Iwata, Shinobu Hashimoto, “Synthesis and Evaluation of Manganese-Doped Calcium Aluminate Red Phosphor”, 2010 Mie Industrial Research Institute Research Report No. 35 (2011).

JP 2007-31668 A WO2004 / 101711A1

Although it is known that the Mn-doped MgGa ₂ O ₄ proposed in Patent Document 1 emits fluorescence, these are phosphors emitting green light or phosphors emitting green and red at the same time. It did not emit light. Similarly, the Mn-doped MgAl ₂ O ₄ proposed in Patent Document 2 is also known to emit fluorescence, but these are phosphors that emit green light or phosphors that emit green and red at the same time. It did not emit red light with emission brightness. Thus, conventionally, there is no oxide fluorescent light emitter that mainly emits red light, and the light emission mechanism has not been studied.

  The present invention has been made on the basis of knowledge obtained in the process of studying a light emission mechanism capable of emitting red fluorescence, and an object thereof is an oxide fluorescent light emitter that emits red fluorescence and a method for producing the same. Is to provide.

(1) The oxide fluorescent substance according to the present invention for solving the above-mentioned problem is an excess amount exceeding the stoichiometric ratio, in which the A site element is Mg and the B site element is Al or Ga, Mn is doped. AB ₂ O ₄ spinel type oxide containing Mg, and when the B site element is Al, the excess amount of Mg is 0 as the stoichiometric ratio with respect to A in the AB ₂ O ₄ spinel type oxide. In the range of not less than 1 and not more than 0.7, the doping amount of Mn is in the range of not less than 0.05 mol% and not more than 0.2 mol% with respect to the AB ₂ O ₄ spinel type oxide, When the site element is Ga, the excess amount of Mg is in the range of 0.1 to 0.9 in terms of the stoichiometric ratio to A in the AB ₂ O ₄ spinel oxide, and the doping amount of Mn is to the _AB 2 _{O 4} spinel oxide .025 in the range of mol% 0.2 mol% or less, and wherein the.

  According to the present invention, a specific spinel oxide doped with Mn and containing an excessive amount of Mg exceeding the stoichiometric ratio can be used as a red fluorescent material.

  In the oxide fluorescent substance according to the present invention, the excessive amount of Mg appears as magnesium oxide in the X-ray diffraction pattern.

  In the oxide fluorescent substance according to the present invention, the doped Mn does not appear as Mn or a Mn compound in the X-ray diffraction pattern.

  The oxide fluorescent substance according to the present invention has a fluorescent emission peak in the range of 620 nm to 750 nm.

(2) The method for producing an oxide fluorescent light emitter according to the present invention for solving the above-described problem is that the A site element is Mg, the B site element is Al or Ga, Mn is doped, and the stoichiometric ratio is A method for producing an AB ₂ O ₄ spinel-type oxide fluorescent material containing an excessive amount of Mg,
A step of preparing a raw material containing an Mg compound as an A-site element raw material, an Al compound or Ga compound as a B-site element raw material and an Mn compound as a doping element raw material, and mixing the raw materials by a solid-phase reaction method or a solution method And after firing,
When the B site element raw material is an Al compound, the raw material is an excessive amount of Mg compound in a stoichiometric ratio with respect to A in the AB ₂ O ₄ spinel oxide in the range of 0.1 to 0.7. And a Mn compound in the range of 0.05 mol% or more and 0.2 mol% or less with respect to the AB ₂ O ₄ spinel type oxide,
When the B site element raw material is a Ga compound, the raw material is an excessive amount of Mg compound in a stoichiometric ratio of 0.1 to 0.9 in the AB ₂ O ₄ spinel type oxide. And a Mn compound in a range of 0.025 mol% to 0.2 mol% with respect to the AB ₂ O ₄ spinel type oxide.

  According to the present invention, a specific spinel type oxide doped with Mn and containing an excessive amount of Mg exceeding the stoichiometric ratio can be used as a red fluorescent emitter, and the spinel type oxide is produced. By making the raw material for this in the said range, a desired red fluorescent light-emitting body can be manufactured.

  In the method for producing an oxide fluorescent substance according to the present invention, the firing can be configured to fire the prepared raw material in a temperature range of 1300 ° C. or higher and 1700 ° C. or lower.

  In the method for producing an oxide fluorescent substance according to the present invention, the mixing by the solution method is performed by dissolving the prepared raw material by heating and dissolving in an organic solvent to prepare a raw material solution (preparing a raw material solution). After baking, it can be configured to fire (fire) in a temperature range of 1300 ° C. or higher and 1700 ° C. or lower.

  According to the present invention, by studying a light emission mechanism that can emit red light, an oxide fluorescent light emitter that emits red light and a method for manufacturing the same can be provided. In particular, since it can be manufactured using inexpensive Mg or Al, an inexpensive oxide fluorescent light emitter can be provided.

Is a powder X-ray diffraction measurement results of MgAl ₂ O ₄ based oxide fluorescent emitters is an oxide fluorescent emitters according to the present invention. A MgGa ₂ O ₄ based oxide powder X-ray diffraction measurement results of the fluorescent emitters is an oxide fluorescent emitters according to the present invention. Excitation spectrum of MgAl ₂ O ₄ based oxide fluorescent emitter with excess Mg (0.3 in stoichiometric ratio to A in AB ₂ O ₄ spinel oxide) and 0.1 mol% doped Mn (Λem = 652 nm) measurement result and fluorescence spectrum measurement result (A) measured at an excitation wavelength λex = 290 nm, a photograph (B) showing a state under a fluorescent lamp, and emission at an excitation wavelength λex = 254 nm It is the photograph (C) which shows a state. In an MgAl ₂ O ₄ oxide fluorescent light emitter having 0.1 mol% doped Mn, an excessive amount of Mg is 0 to 0.7 in terms of a stoichiometric ratio with respect to A in the AB ₂ O ₄ spinel oxide. It is the measurement result of the excitation spectrum ((lambda) em = 652nm) when it changes by the range, and the measurement result of the fluorescence spectrum measured by excitation wavelength (lambda) ex = 290nm. In an MgAl ₂ O ₄ -based oxide fluorescent light emitter having an excess amount of Mg of 0.5 (stoichiometric ratio to A in AB ₂ O ₄ spinel type oxide), Mn to be doped is 0.025 mol% to 1 It is the measurement result of the excitation spectrum ((lambda) em = 652nm) when it changes in the range of mol%, and the measurement result of the fluorescence spectrum measured by excitation wavelength (lambda) ex = 290nm. MgGa ₂ O ₄ -based oxide fluorescence with an excess amount of Mg (0.5 stoichiometric ratio to A in AB ₂ O ₄ spinel oxide) and 0.1 mol% or 1 mol% doped Mn Measurement result of body excitation spectrum (λem = 687 nm), measurement result of fluorescence spectrum measured at excitation wavelength λex = 310 nm (A), photograph (B) showing a state under a fluorescent lamp, excitation wavelength λex = 365 nm It is the photograph (C) which shows the light emission state at the time of. In the MgGa ₂ O ₄ oxide fluorescent light-emitting body having Mn doped with 0.05 mol%, an excess amount of Mg is 0.1 to 0.1 in a stoichiometric ratio with respect to A in the AB ₂ O ₄ spinel type oxide. 9 shows the measurement result of the excitation spectrum (λem = 685 nm) when changed in the range of 9 and the measurement result of the fluorescence spectrum measured at the excitation wavelength λex = 310 nm. In an MgGa ₂ O ₄ -based oxide fluorescent light emitter having an excess amount of Mg of 0.5 (stoichiometric ratio with respect to A in the AB ₂ O ₄ spinel type oxide), Mn to be doped is 0.025 mol% to 1 It is the measurement result of the excitation spectrum ((lambda) em = 687nm) when it changes in the range of mol%, and the measurement result of the fluorescence spectrum measured by excitation wavelength (lambda) ex = 310nm.

  Next, embodiments of the present invention will be described in detail, but the present invention is not limited to the following embodiments, and various modifications can be made within the scope of the gist of the present invention.

[Oxide fluorescent emitter]
The oxide fluorescent substance according to the present invention is an AB ₂ O ₄ spinel oxide in which the A site element is Mg and the B site element is Al or Ga. The spinel type oxide is doped with Mn and contains an excess amount of Mg exceeding the stoichiometric ratio to A in the AB ₂ O ₄ spinel type oxide.

In the MgAl ₂ O ₄ oxide fluorescent light emitter in which the B-site element is Al, this spinel type oxide is (1) the stoichiometry with respect to A in the excess amount of Mg in the AB ₂ O ₄ spinel type oxide. The ratio is in the range of 0.1 to 0.7, and the doping amount of Mn is in the range of 0.05 mol% to 0.2 mol% with respect to the AB ₂ O ₄ spinel oxide, (2) In the MgGa ₂ O ₄ -based oxide fluorescent light emitter in which the B-site element is Ga, the excess amount of Mg is 0.1 or more in terms of the stoichiometric ratio with respect to A in the AB ₂ O ₄ spinel oxide. .9 or less, and the doping amount of Mn is in the range of 0.025 mol% or more and 0.2 mol% or less with respect to the AB ₂ O ₄ spinel type oxide. In any of the oxide fluorescent light emitters thus configured, a red fluorescent light emitter can be obtained when the above-described spinel oxide contains a predetermined excess amount of Mg and a doping amount of Mn.

  Hereinafter, components of the oxide fluorescent light emitter will be described in detail.

(composition)
The oxide fluorescent light emitter is an AB ₂ O ₄ spinel oxide in which the A site element is Mg and the B site element is Al or Ga. When the B site element is Al, it is MgAl ₂ O ₄ , and when the B site element is Ga, it is MgGa ₂ O ₄ . The subscript number of the oxide indicates the stoichiometric ratio, and the Mg number is omitted although it is 1. This stoichiometric ratio is a molar ratio. For MgAl ₂ O ₄ , Mg is composed of 1 mole, Al is 2 moles, and O is 4 moles.

The oxide fluorescent light emitter contains an excessive amount of Mg. In the MgAl ₂ O ₄ oxide fluorescent light emitter in which the B site element is Al, the excess amount of Mg is 0.1 to 0.7 in terms of the stoichiometric ratio (molar ratio) to Mg in MgAl ₂ O _4. It is included within the following range. An MgAl ₂ O ₄ -based oxide fluorescent light emitter having an excessive amount of Mg within this range can emit red light with high intensity. When the excess amount of Mg is less than 0.1, the emission intensity is lower than in the above range, and when the excess amount of Mg exceeds 0.7, the emission intensity is also higher than in the above range. Decreases. For example, when Mg is excessively contained by 0.3, the stoichiometric ratio (molar ratio) of the total Mg is 1.3.

On the other hand, in the MgGa ₂ O ₄ oxide fluorescent light emitter in which the B-site element is Ga, the excess amount of Mg is 0.1 or more in terms of the stoichiometric ratio (molar ratio) to Mg in MgGa ₂ O _4. Within the range of .9 or less. An MgGa ₂ O ₄ -based oxide fluorescent light emitter having an excessive amount of Mg within this range can emit red light with high intensity. When the excess amount of Mg is less than 0.1, the emission intensity is lower than in the above range, and when the excess amount of Mg exceeds 0.9, the emission intensity is also higher than in the above range. Decreases.

The oxide fluorescent light emitter is doped with Mn. In the MgAl ₂ O ₄ oxide fluorescent light emitter in which the B site element is Al, the doping amount of Mn is 0.05 mol% or more and 0.2 mol% or less when AB ₂ O ₄ is 1 mol. Is included in the range. An MgAl ₂ O ₄ -based oxide fluorescent light emitter having a doping amount of Mn within this range can emit red light with high intensity. When the doping amount of Mn is less than 0.05 mol%, the emission intensity is lower than in the above range, and when the doping amount of Mn exceeds 0.2 mol%, it is also compared with that in the above range. As a result, the emission intensity decreases.

On the other hand, in the MgGa ₂ O ₄ -based oxide fluorescent light emitter in which the B-site element is Ga, the doping amount of Mn is 0.025 mol% or more and 0.2 mol when AB ₂ O ₄ is 1 mol. % Or less is included. An MgGa ₂ O ₄ -based oxide fluorescent light emitter having a doping amount of Mn within this range can emit red light with high intensity. When the doping amount of Mn is less than 0.025 mol%, the emission intensity is lower than in the above range, and when the doping amount of Mn exceeds 0.2 mol%, it is also compared with the case in the above range. As a result, the emission intensity decreases.

AB ₂ O ₄ in which the A site element is Mg and the B site element is Al or Ga is allowed even if it is not a strict stoichiometric ratio, and the A site stoichiometric ratio is 0.99 to 1. Within the range of .01, the stoichiometric ratio of the B site may be within the range of 1.98 to 2.02, and the stoichiometric ratio of O (oxygen) is 3.96 to 4.04. If it is within the range, the emission intensity is not greatly affected.

  The composition of the oxide fluorescent light emitter can be quantified with a wavelength dispersive X-ray fluorescence analyzer or the like.

(X-ray diffraction pattern)
As an X-ray diffraction pattern of the oxide fluorescent light emitter, in the MgAl ₂ O ₄ -based oxide fluorescent light emitter whose B site element is Al, as shown in FIG. 1, the MgAl ₂ O ₄ diffraction peak and the excess amount of Mg And a MgO diffraction peak showing. From this X-ray diffraction pattern, it is understood that an excessive amount of Mg is contained as MgO in the spinel oxide fluorescent light emitter. Thus, excess Mg, together with MgAl ₂ O ₄ in an oxide fluorescent emitters, stoichiometric ratio of Mg in MgAl ₂ O ₄ (molar ratio) at 0.1 or more, a range of 0.7 or less It can be said that it is contained as MgO. On the other hand, doped Mn showed no diffraction peak as Mn simple substance or Mn compound.

In addition, in the MgGa ₂ O ₄ -based oxide fluorescent light emitter in which the B site element is Ga, as shown in FIG. 2, a MgGa ₂ O ₄ diffraction peak and a MgO diffraction peak indicating an excess amount of Mg appear. From this X-ray diffraction pattern, it is understood that an excess amount of Mg is contained as MgO in the spinel oxide fluorescent light emitter, as in MgAl ₂ O ₄ . Thus, excess Mg, together with MgGa ₂ O ₄ in an oxide fluorescent emitters, stoichiometric ratio of Mg in MgGa ₂ O ₄ (molar ratio) at 0.1 or more, 0.9 or less It can be said that it is contained as MgO. On the other hand, doped Mn showed no diffraction peak as Mn simple substance or Mn compound.

(Fluorescence emission characteristics)
FIG. 3 (C) is a photograph showing a light emission state of an MgAl ₂ O ₄ -based oxide fluorescent light emitter containing an excessive amount of Mg and doped Mn, and FIG. 6 (C) shows an excessive amount of Mg and is a photograph showing the emission state of MgGa ₂ O ₄ based oxide fluorescent emitters including the doped Mn. All of these luminescences show a light emission state when the excitation wavelength λex = 254 nm, indicating a good light emission state. FIG. 3B is a photograph showing a light emission state under a commercially available fluorescent lamp, and FIG. 6B is also a photograph showing a light emission state under a commercially available fluorescent lamp. Yes, it turns out that none of them emits red light.

As will be described later in the examples and FIG. 3 and the like regarding this light emission state, the oxide fluorescent light emitter according to the present invention has, for example, an excitation wavelength λex = 290 nm with respect to an MgAl ₂ O ₄ oxide fluorescent light emitter. In any case where the excitation wavelength λex = 310 nm for the MgGa ₂ O ₄ -based oxide fluorescent light emitter, it has a fluorescence spectrum peak in the range of 620 nm to 750 nm and emits red light.

(Properties)
The property of the oxide fluorescent substance is usually a powder at normal temperature / normal humidity (25 ° C. ± 5 ° C./50%±10% RH). The average particle size of the powder is usually in the range of 1 nm or more and 50 nm or less. The particle diameter can be measured, for example, by a small angle scattering X-ray method. As a measuring apparatus, for example, SmartLab manufactured by Rigaku Corporation can be used.

In the oxide fluorescent light emitter according to the present invention, the excitation wavelength clearly appears in the vicinity of 290 nm and 440 nm in the MgAl ₂ O ₄ oxide fluorescent light emitter, and in the MgGa ₂ O ₄ oxide fluorescent light emitter, Excitation wavelengths clearly appear around 310 nm and around 470 nm. Therefore, in the present invention, the fluorescence spectrum is measured at the excitation wavelength λex = 290 nm in the MgAl ₂ O ₄ based oxide fluorescent light emitter, and the excitation wavelength λex = 310 nm in the MgGa ₂ O ₄ based oxide fluorescent light emitter. When the fluorescence spectrum was measured, it was found that each had a fluorescence spectrum peak in the range of 620 nm to 750 nm and emitted red light. Thus, the oxide fluorescent substance according to the present invention can be excited by ultraviolet light and visible light. This oxide fluorescent light-emitting body may be obtained by a production method described later, or may be obtained by any other production method.

  As described above, the oxide fluorescent light emitter according to the present invention can emit red light, and can be manufactured using inexpensive Mg or Al, so that an inexpensive oxide fluorescent light emitter is provided. be able to.

[Production method]
In the method for producing an oxide fluorescent light emitter according to the present invention, the A site element is Mg, the B site element is Al or Ga, Mn is doped, and AB ₂ O containing excess Mg exceeding the stoichiometric ratio is contained. It is a manufacturing method of ₄ spinel type oxide fluorescent substance. This manufacturing method includes a step of preparing a raw material containing an Mg compound that is an A-site element raw material, an Al compound or Ga compound that is a B-site element raw material, and an Mn compound that is a doping element raw material; Or it has the process of baking after mixing by a solution method.

When the B site element raw material is an Al compound, the raw material is an excess amount of Mg compound in the range of 0.1 to 0.7 in terms of the stoichiometric ratio to Mg in the MgAl ₂ O ₄ spinel type oxide. And a Mn compound in the range of 0.05 mol% or more and 0.2 mol% or less with respect to the MgAl ₂ O ₄ spinel type oxide, and a raw material when the B site element raw material is a Ga compound 0 but with an excess of Mg compounds within the scope of 0.1 to 0.9 in a stoichiometric ratio to the Mg of MgGa ₂ O ₄ spinel oxide, relative MgGa ₂ O ₄ spinel oxide And a Mn compound within a range of 0.25 mol% or more and 0.2 mol% or less.

By this production method, an AB ₂ O ₄ spinel oxide containing the excessive amount of Mg compound and the Mn compound within the above range, wherein the A site element is Mg and the B site element is Al or Ga is produced. it can. Details of such oxide fluorescent light emitters show the composition and X-ray diffraction pattern as described above, and MgAl ₂ O ₄ based oxide fluorescent light emitters emit fluorescence within the range of 620 nm to 750 nm at excitation wavelength λex = 290 nm. It has a spectrum peak and emits red light, and the MgGa ₂ O ₄ -based oxide fluorescent light emitter has a fluorescence spectrum peak in the range of 620 nm to 750 nm at an excitation wavelength λex = 310 nm and emits red light.

  Hereinafter, each step will be described.

(Raw material preparation process)
The raw material includes an Mg compound that is an A-site element material, an Al compound or Ga compound that is a B-site element material, and an Mn compound that is a dope element material. Examples of the compound include oxides, hydroxides, acetates, nitrates, carbonates, and chlorides. A compound is selected depending on whether these raw materials are mixed by a solid phase reaction method or a solution method. For example, in the case of mixing by a solid phase reaction method, it is not necessary to consider the solubility in a solvent, so an oxide or the like can be selected. On the other hand, when mixing by a solution method, since it is necessary to consider the solubility in a solvent, it is preferable to select an ionic compound salt or the like having solvent solubility.

  Examples of such various salts include magnesium oxide, magnesium carbonate, magnesium nitrate and the like. Examples of the Al compound include aluminum oxide and aluminum nitrate. Examples of the Ga compound include gallium oxide and potassium nitrate. Examples of the Mn compound include manganese carbonate, manganese oxide, and manganese nitrate.

  The particle size and the like of the raw material powder are not particularly limited, but for example, in the case of an oxide, it is preferably in the range of 1 μm or less. By using a powder having a size within this range, the raw materials can be easily mixed.

Blending of raw materials, in case of producing a MgAl ₂ O ₄ based oxide fluorescent emitters, as B-site element A site element in Mg is MgAl ₂ O ₄ based oxides Al, A-site element material The Mg compound is mixed so that the stoichiometric ratio to Mg in the MgAl ₂ O ₄ spinel type oxide is an excess amount in the range of 0.1 to 0.7, and the B site element material Al Compound raw materials are blended by the stoichiometric ratio, and the Mn compound, which is a dope element material, is blended so as to be in the range of 0.05 mol% to 0.2 mol% with respect to the MgAl ₂ O ₄ spinel type oxide. To do.

In the case of manufacturing an MgGa ₂ O ₄ -based oxide fluorescent light emitter, Mg that is an A-site element raw material is an MgGa ₂ O ₄ -based oxide in which the A-site element is Mg and the B-site element is Ga. The compound is blended so that the stoichiometric ratio with respect to Mg in the MgGa ₂ O ₄ spinel-type oxide is an excess amount in the range of 0.1 or more and 0.9 or less, and a Ga compound material that is a B site element material is added. formulated by stoichiometry content, blending the Mn compound is doped elemental material such that MgGa ₂ O ₄ spinel oxide with respect to the range of 0.025 mol% to 0.2 mol% or less.

  Since the composition of the raw materials is the same as the composition of the finally obtained oxide fluorescent light emitter, the necessary amount is weighed and blended.

By this production method, the excessive amount of Mg compound and the Mn compound within the above range can be contained and produced. The details of such oxide fluorescent light emitters show the composition and X-ray diffraction pattern as described above. For example, in the case of MgAl ₂ O ₄ -based oxide fluorescent light emitters, when the excitation wavelength is λex = 290 nm, the range is 620 nm to 750 nm. It has a fluorescence spectrum peak inside and emits red light. Further, the MgGa ₂ O ₄ -based oxide fluorescent light emitter has a fluorescence spectrum peak in the range of 620 nm to 750 nm and emits red light when the excitation wavelength λex = 310 nm.

(Baking process)
A baking process is a process of baking, after mixing a raw material with a solid-phase reaction method or a solution method. Mixing can be carried out with a mixing device such as a ball mill after weighing an appropriate amount of each of the above-mentioned raw materials.

  In the solid phase reaction method, the prepared raw materials are mixed and then fired. Firing is preferably performed in a temperature range of 1300 ° C. or higher and 1700 ° C. or lower, and more preferably performed in a temperature range of 1400 ° C. or higher and 1600 ° C. or lower. The firing atmosphere is preferably in the air or in an oxygen atmosphere.

  In the solution method, a prepared raw material is heated and dissolved in an organic solvent to form a raw material solution (preparation of raw material solution), and the raw material solution is calcined and then fired in a temperature range of 1300 ° C. to 1700 ° C. (firing).

  The solvent used in the solution method needs to be water or an organic solvent capable of dissolving the raw material. There is no restriction | limiting in particular as a solvent, For example, a polyhydric alcohol, a monosaccharide, a disaccharide etc. can be mentioned. More specifically, mention is made of at least one selected from the group consisting of ethylene glycol, propylene glycol, 1,2-butylene glycol, 2,3-butylene glycol, trimethylene glycol, glycerin, erythritol, xylitol, and sorbitol. Can do.

  In the solution method, heat concentration may be optionally performed. In this heat concentration, the raw material solution is heated and concentrated to remove water in the raw material solution to obtain a highly viscous solution. The heating temperature is usually 100 ° C. or higher and 150 ° C. or lower. The atmosphere for the heat treatment is not particularly limited, and may be any of an air atmosphere, an inert atmosphere such as a nitrogen atmosphere and argon.

  In the solution method, calcination is performed. In this calcination, a high-viscosity solution obtained by heat concentration is further heat-treated to remove at least a part of the water-soluble organic compound in the high-viscosity solution to obtain a powder. As the heat treatment temperature, for example, in the case of propylene glycol described above, about 250 ° C. (about 230 ° C. to 270 ° C.) which is about 60 ° C. (range of about 40 ° C. to 80 ° C.) higher than its boiling point (188.2 ° C.). Range). The atmosphere for the heat treatment is not particularly limited, and may be any of an air atmosphere, an inert atmosphere such as a nitrogen atmosphere and argon.

  As in the case of the solid phase reaction method described above, the firing is preferably performed in a temperature range of 1300 ° C. or higher and 1700 ° C. or lower, and more preferably performed in a temperature range of 1400 ° C. or higher and 1600 ° C. or lower. The firing atmosphere is preferably an oxygen atmosphere in the air.

  The oxide fluorescent substance according to the present invention can be manufactured through these steps.

  EXAMPLES The present invention will be described more specifically with reference to examples. However, the present invention is not limited to the description of the following examples unless it exceeds the gist.

[Experimental Example 1: MgAl ₂ O ₄ -based oxide phosphor]
(Sample preparation)
A MgAl ₂ O ₄ oxide fluorescent light emitter was synthesized by a solid phase reaction method. As raw materials, MgO powder (99.99%), α-Al ₂ O ₃ powder (99.99%), and MnCO ₃ powder (99.9%) were used (all at High Purity Chemical Laboratory Co., Ltd.). 0.26198 g of MgO, 0.50981 g of Al ₂ O ₃ , and 0 of MnCO _{3 so} that each powder has a stoichiometric ratio of “0.3 MgO—MgAl ₂ O ₄ ; 0.1 mol% Mn”. .00057 g was weighed. Each weighed raw material was mixed for 10 minutes by a dry mixing method using an agate mortar, then mixed for 20 minutes by a wet mixing method, and baked in the atmosphere at 1400 ° C. for 5 hours, and then “0.3 MgO—MgAl ₂ of Experimental Example 1 was used. An oxide fluorescent substance of “O ₄ ; 0.1 mol% Mn” was obtained. The wet mixing method here is a method in which oxide powder is mixed in ethanol.

(Fluorescence / excitation spectrum measurement)
The fluorescence / excitation spectrum of the obtained oxide fluorescent material was measured. For fluorescence / excitation spectrum measurement, a spectrofluorometer (manufactured by JASCO Corporation, FP-6300 type) is used, and as a filter, a sharp cut filter L-37 (manufactured by HOYA Corporation) is blocked at a wavelength of 370 nm or less. The sample was packed in a powder measurement folder and set in a spectrofluorometer to measure. In addition, the detection of the double wave was eliminated by attaching a filter to the spectrofluorometer. The fluorescence spectrum was expressed as a result obtained by fixing the wavelength on the excitation side to 290 nm and scanning the wavelength on the fluorescence side in the range of 200 nm to 550 nm. The excitation spectrum was expressed by the fluorescence intensity with respect to the excitation light wavelength (λex = 290 nm) by fixing the wavelength on the fluorescence side to the maximum wavelength (λem = 652 nm), scanning the wavelength on the excitation side.

  FIG. 3A shows the measurement result of the excitation spectrum (λem = 652 nm) of the oxide fluorescent substance and the measurement result of the fluorescence spectrum measured at the excitation wavelength λex = 290 nm. This oxide fluorescent substance emitted fluorescence in the range of 620 nm to 750 nm, and showed the highest emission peak at around 640 nm. FIG. 3B is a photograph showing a state under a commercially available fluorescent lamp, and FIG. 3C is a photograph showing a light emission state at an excitation wavelength λex = 254 nm.

[Experimental example 2: Effect of excess amount of Mg]
In the same manner as in Experimental Example 1, a MgAl ₂ O ₄ oxide fluorescent light emitter was synthesized by a solid phase reaction method. Each powder was weighed so that the stoichiometric ratio was “xMgO—MgAl ₂ O ₄ ; 0.1 mol% Mn”. Here, x is an excess amount of Mg, and 0, 0.05, 0.1, 0.2, 0.3, 0.5 in stoichiometric ratio with respect to Mg in the MgAl ₂ O ₄ spinel type oxide. , 0.7 were prepared. Each raw material weighed was mixed for 10 minutes by a dry mixing method using an agate mortar, then mixed for 20 minutes by a wet mixing method, and baked at 1400 ° C. for 5 hours in the atmosphere. “XMgO—MgAl ₂ O _{4 of} Experimental Example 2” ; 0.1 mol% Mn "was obtained.

The X-ray diffraction pattern of the obtained oxide fluorescent substance was measured. The measurement was performed using a RINT2200 type manufactured by Rigaku Corporation as a powder X-ray diffractometer under the conditions of CuKα rays, an applied voltage of 40 kV, and an applied current of 40 mA. FIG. 1 shows the obtained powder X-ray diffraction measurement results. As shown in FIG. 1, it was confirmed that the diffraction pattern of the MgAl ₂ O ₄ -based oxide fluorescent light emitter appeared. It was also confirmed that an excessive amount of Mg appeared as magnesium oxide in the X-ray diffraction pattern, and the diffraction peak increased as the excessive amount increased. However, it was also confirmed that doped Mn does not appear as Mn or a Mn compound in the X-ray diffraction pattern.

  The fluorescence / excitation spectrum of the obtained oxide fluorescent material was measured in the same manner as in Experimental Example 1. FIG. 4 shows the measurement result of the excitation spectrum (λem = 652 nm) of the oxide fluorescent substance and the measurement result of the fluorescence spectrum measured at the excitation wavelength λex = 290 nm. This oxide fluorescent substance showed a high emission peak when x was in the range of 0.1 to 0.7.

[Experimental Example 3: Influence of doping amount of Mn]
In the same manner as in Experimental Example 1, a MgAl ₂ O ₄ oxide fluorescent light emitter was synthesized by a solid phase reaction method. Each powder was weighed so that the stoichiometric ratio was “0.5MgO—MgAl ₂ O ₄ ; yMn”. Here, y is the doping amount of Mn (mol% with respect to MgAl ₂ O ₄ spinel oxide), 0, 0.025, 0.05, 0.1, 0.2, 0.5, Each of 1.0 was prepared. Each raw material weighed was mixed for 10 minutes by a dry mixing method using an agate mortar, then mixed for 20 minutes by a wet mixing method, and baked in the atmosphere at 1400 ° C. for 5 hours to obtain “0.5MgO—MgAl ₂ of Experimental Example 3”. An oxide fluorescent emitter of “O ₄ ; yMn” was obtained.

  The fluorescence / excitation spectrum of the obtained oxide fluorescent material was measured in the same manner as in Experimental Example 1. FIG. 5 shows the measurement result of the excitation spectrum (λem = 652 nm) of the oxide fluorescent substance and the measurement result of the fluorescence spectrum measured at the excitation wavelength λex = 290 nm. This oxide fluorescent substance showed a high emission peak when y was in the range of 0.05 mol% to 0.2 mol%.

[Experimental Example 4: Influence of firing conditions]
In the same manner as in Experimental Example 1, a MgAl ₂ O ₄ oxide fluorescent light emitter was synthesized by a solid phase reaction method. Each powder was weighed so that the stoichiometric ratio was “0.5MgO—MgAl ₂ O ₄ ; 0.1 mol% Mn”. Each weighed raw material was mixed for 10 minutes by a dry mixing method using an agate mortar and then mixed for 20 minutes by a wet mixing method. The firing conditions were an air atmosphere, an oxygen atmosphere in which oxygen was flowed at 10 mL / min, and a nitrogen atmosphere in which nitrogen was flowed at 10 mL / min. The firing temperature was 1400 ° C. for 5 hours and 1600 ° C. for 5 hours. Thus, an oxide fluorescent light emitting material of “0.5 MgO—MgAl ₂ O ₄ ; 0.1 mol% Mn” in Experimental Example 4 was obtained.

  The fluorescence / excitation spectrum of the obtained oxide fluorescent material was measured in the same manner as in Experimental Example 1. Although the results are not shown, those fired in an air atmosphere and an oxygen atmosphere showed high emission peaks. Further, firing at 1600 ° C. showed a higher emission peak.

[Experimental Example 5: Preparation by solution method]
A MgAl ₂ O ₄ oxide fluorescent light emitter was synthesized by a solution method. Raw materials were magnesium nitrate dihydrate [Mg (NO ₃ ) ₂ .2H ₂ O], aluminum nitrate nonahydrate [Al (NO ₃ ) ₃ .9H ₂ O], manganese acetate tetrahydrate [Mn ( CH ₃ COO) ₂ .4H ₂ O] and water are prepared, and 0.26198 g of MgO and 0 of Al ₂ O ₃ are added so that “0.5 MgO—MgAl ₂ O ₄ ; 0.1 mol%” is obtained. 50981 g and 0.00057 g of MnCO ₃ were weighed and mixed, and an organic compound (diethylene glycol) was added to prepare a raw material solution. At this time, diethylene glycol was added in an amount four times the aluminum molar ratio used. Next, the raw material powder was dissolved in an organic solvent by heating the raw material solution at about 110 ° C. for 10 minutes (heating dissolution). Next, the sol was heated (pre-calcined) at 350 ° C. for 3 hours in the air atmosphere, and then heated at 1400 ° C. for 5 hours in the air atmosphere to remove carbon (organic material), and then at 1600 ° C. in the air atmosphere. Firing was performed for 5 hours. Thus, “0.5MgO—MgAl ₂ O ₄ ; 0.1 mol% Mn” of Experimental Example 5 was produced by a solution method.

  The fluorescence / excitation spectrum of the obtained oxide fluorescent material was measured in the same manner as in Experimental Example 1. Although the result was not shown, it showed a high emission peak.

[Experimental example 6: MgGa ₂ O ₄ -based oxide phosphor]
MgGa ₂ O ₄ -based oxide fluorescent emitters were synthesized by a solid phase reaction method. As raw materials, MgO powder (99.99%), Ga ₂ O ₃ powder (99.9%), and MnCO ₃ powder (99.9%) were used (all at High Purity Chemical Laboratory Co., Ltd.). Each powder was weighed such that 0.30228 g of MgO, 0.93722 g of Ga ₂ O ₃ and 0.00029 g of MnCO ₃ were adjusted so that the stoichiometric ratio was “0.5MgO—MgGa ₂ O ₄ ; yMn”. Here, y is the doping amount of Mn (mol% with respect to MgGa ₂ O ₄ spinel oxide), 0, 0.025, 0.05, 0.1, 0.2, 0.5, Each of 1.0 was prepared. Each raw material was weighed in, a wet mixing method was mixed for 20 minutes after mixing for 10 minutes in a dry mixing method using an agate mortar and fired in air 1400 ° C. 5 hours, of Experimental Example 6 "0.5MgO-MgGa ₂ An oxide fluorescent emitter of “O ₄ ; yMn” was obtained.

  The fluorescence / excitation spectrum of the obtained oxide fluorescent material was measured in the same manner as in Experimental Example 1. FIG. 6A shows the measurement result of the excitation spectrum (λem = 687 nm) of the oxide fluorescent substance and the measurement result of the fluorescence spectrum measured at the excitation wavelength λex = 310 nm. This oxide fluorescent substance emitted fluorescence in the range of 620 nm to 750 nm, and showed the highest emission peak at around 687 nm. FIG. 6B is a photograph showing a state under a commercially available fluorescent lamp, and FIG. 6C is a photograph showing a light emission state at an excitation wavelength λex = 365 nm.

[Experimental Example 7: Effect of excess amount of Mg]
In the same manner as in Experimental Example 6, an MgGa ₂ O ₄ -based oxide fluorescent light emitter was synthesized by a solid phase reaction method. Each powder was weighed so that the stoichiometric ratio was “xMgO—MgGa ₂ O ₄ ; 0.05 mol% Mn”. Here, x is an excess amount of Mg, and the stoichiometric ratio with respect to Mg in the MgGa ₂ O ₄ spinel type oxide was set to 0.1, 0.3, 0.5, 0.7, 0.9. Each was made. Each raw material weighed was mixed for 10 minutes by a dry mixing method using an agate mortar, then mixed for 20 minutes by a wet mixing method, fired in the atmosphere at 1400 ° C. for 5 hours, and “xMgO—MgGa ₂ O _{4 of} Experimental Example 7”. ; 0.05 mol% Mn "was obtained.

The X-ray diffraction pattern of the obtained oxide fluorescent substance was measured. The measurement was performed using a RINT2200 type manufactured by Rigaku Corporation as a powder X-ray diffractometer under the conditions of CuKα rays, an applied voltage of 40 kV, and an applied current of 40 mA. FIG. 2 shows the obtained powder X-ray diffraction measurement results. As shown in FIG. 2, it was confirmed that the diffraction pattern of the MgGa ₂ O ₄ -based oxide fluorescent light emitter appeared. It was also confirmed that an excessive amount of Mg appeared as magnesium oxide in the X-ray diffraction pattern, and the diffraction peak increased as the excessive amount increased. However, it was also confirmed that doped Mn does not appear as Mn or a Mn compound in the X-ray diffraction pattern.

  The fluorescence / excitation spectrum of the obtained oxide fluorescent material was measured in the same manner as in Experimental Example 6. FIG. 7 shows the measurement result of the excitation spectrum (λem = 685 nm) of the oxide fluorescent substance and the measurement result of the fluorescence spectrum measured at the excitation wavelength λex = 310 nm. This oxide fluorescent substance showed a high emission peak when x was in the range of 0.1 to 0.9.

[Experimental Example 8: Effect of doping amount of Mn]
In the same manner as in Experimental Example 6, an MgGa ₂ O ₄ -based oxide fluorescent light emitter was synthesized by a solid phase reaction method. Each powder was weighed so that the stoichiometric ratio was “0.5MgO—MgGa ₂ O ₄ ; yMn”. Here, y is the doping amount of Mn (mol% with respect to MgGa ₂ O ₄ spinel oxide), and is 0.025, 0.05, 0.1, 0.2, 0.5, 1. Each set to 0 was prepared. Each raw material was weighed in, a wet mixing method was mixed 20 minutes after mixing for 10 minutes in a dry mixing method using an agate mortar and fired in air 1400 ° C. 5 hours, in Experimental Example 8 "0.5MgO-MgGa ₂ An oxide fluorescent emitter of “O ₄ ; yMn” was obtained.

The fluorescence / excitation spectrum of the obtained oxide fluorescent material was measured in the same manner as in Experimental Example 6. FIG. 8 shows the measurement result of the excitation spectrum (λem = 687 nm) of the oxide fluorescent substance and the measurement result of the fluorescence spectrum measured at the excitation wavelength λex = 310 nm. This oxide fluorescent substance showed a high emission peak when y was in the range of 0.025 mol% to 0.2 mol%.

Claims (7)

An AB ₂ O ₄ spinel type oxide in which the A-site element is Mg, the B-site element is Al or Ga, Mn is doped, and contains an excessive amount of Mg exceeding the stoichiometric ratio,
In the case where the B site element is Al, the excess amount of Mg is in the range of 0.1 to 0.7 in terms of the stoichiometric ratio to A in the AB ₂ O ₄ spinel oxide, and the doping of Mn The amount is in the range of 0.05 mol% or more and 0.2 mol% or less with respect to the AB ₂ O ₄ spinel oxide,
In the case where the B-site element is Ga, the excess amount of Mg is in the range of 0.1 to 0.9 in terms of the stoichiometric ratio to A in the AB ₂ O ₄ spinel oxide, and Mn doping The oxide fluorescent substance characterized in that the amount is in the range of 0.025 mol% or more and 0.2 mol% or less with respect to the AB ₂ O ₄ spinel type oxide.   The oxide fluorescent light-emitting body according to claim 1, wherein the excessive amount of Mg appears as magnesium oxide in an X-ray diffraction pattern.   The oxide fluorescent substance according to claim 1 or 2, wherein the doped Mn does not appear as Mn or a Mn compound in an X-ray diffraction pattern.   The oxide fluorescent substance according to any one of claims 1 to 3, which has a fluorescent emission peak in a range of 620 nm to 750 nm. A method for producing an AB ₂ O ₄ spinel oxide fluorescent light emitter in which an A-site element is Mg and a B-site element is Al or Ga, Mn is doped, and an excess amount of Mg exceeding the stoichiometric ratio is included. ,
A step of preparing a raw material containing an Mg compound as an A-site element raw material, an Al compound or Ga compound as a B-site element raw material and an Mn compound as a doping element raw material, and mixing the raw materials by a solid-phase reaction method or a solution method And after firing,
When the B site element raw material is an Al compound, the raw material is an excessive amount of Mg compound in a stoichiometric ratio with respect to A in the AB ₂ O ₄ spinel oxide in the range of 0.1 to 0.7. And a Mn compound in the range of 0.05 mol% or more and 0.2 mol% or less with respect to the AB ₂ O ₄ spinel type oxide,
When the B site element raw material is a Ga compound, the raw material is an excessive amount of Mg compound in a stoichiometric ratio of 0.1 to 0.9 in the AB ₂ O ₄ spinel type oxide. And a Mn compound in the range of 0.025 mol% or more and 0.2 mol% or less with respect to the AB ₂ O ₄ spinel oxide, and a method for producing an oxide fluorescent light emitter.   The said baking is a manufacturing method of the oxide fluorescent substance of Claim 5 which bakes the prepared said raw material in the temperature range of 1300 degreeC or more and 1700 degrees C or less. 6. The mixing by the solution method is performed by heating and dissolving the prepared raw material in an organic solvent to obtain a raw material solution, and calcining the raw material solution in a temperature range of 1300 ° C. or higher and 1700 ° C. or lower. The manufacturing method of the oxide fluorescent substance of description.