CN113185974B

CN113185974B - Indium strontium pyrophosphate fluorescent matrix material, fluorescent material, and preparation and application thereof

Info

Publication number: CN113185974B
Application number: CN202010036845.1A
Authority: CN
Inventors: 蔡格梅; 刘一佳; 张更鑫; 张静
Original assignee: Central South University
Current assignee: Central South University
Priority date: 2020-01-14
Filing date: 2020-01-14
Publication date: 2022-11-08
Anticipated expiration: 2040-01-14
Also published as: CN113185974A

Abstract

The invention belongs to the field of fluorescent materials, and particularly discloses an indium strontium pyrophosphate fluorescent substrate material with a chemical formula of Sr ₂ In(PO ₄ )(P ₂ O ₇ ). The invention also provides a preparation method of the substrate, which comprises the steps of mixing the strontium source, the indium source and the phosphate source according to the stoichiometric ratio of the chemical formula to obtain a mixture, and sintering the mixture in multiple stages to obtain the strontium-indium-phosphate composite material. The research of the invention finds that Sr ₂ In(PO ₄ )(P ₂ O ₇ ) Is a brand new compound, and the brand new compound is used as a substrate material for rare earth fluorescent powder, thereby being beneficial to obtaining fluorescent materials with excellent luminescence property.

Description

Indium strontium pyrophosphate fluorescent matrix material, fluorescent material, and preparation and application thereof

The technical field is as follows:

the invention relates to the field of rare earth luminescent materials, in particular to a phosphate matrix material for rare earth fluorescent powder and a preparation method thereof.

The background art comprises the following steps:

with the continuous development of lighting energy-saving technology, the main corner of the traditional lighting market is being converted from incandescent lamps to LEDs. In recent years, semiconductor lighting technologies represented by white LEDs have been rapidly developed, and are widely used in the fields of medical lighting, plant lighting, invisible light application, health lighting, and the like. The fluorescent powder is one of key materials for realizing white light LEDs, and the performance of the fluorescent powder plays an important role in the luminous efficiency and the light quality of the white light LEDs. Fluorescent powder has become an indispensable material in people's daily life. The fluorescent powder is generally synthesized by doping an activator in a matrix, and sometimes a sensitizer is required to be added to enhance the luminous efficiency; very few phosphors are intrinsically luminescent (do not require doping). For the doped fluorescent powder, different substrates have different crystal structures, and the crystal field effect on the doped activated ions is different, so that energy level splitting is influenced, and the difference is expressed as the difference of spectral properties macroscopically. The phosphate is an important fluorescent powder matrix material and has high application value due to the advantages of moderate phonon energy, strong absorption in vacuum ultraviolet-ultraviolet region, high solubility to rare earth ions, stable physical and chemical properties, low cost of raw materials, simple preparation process and the like. Phosphoric acid has been used both domestically and abroad since the sixties and seventies of the last centuryThe research work of the fluorescent powder taking salt as the matrix is continuously carried out, and a series of rare earth phosphate fluorescent powder which can be used in different fields, such as LaPO, are prepared ₄ :Ce ³⁺ ,Tb ³⁺ 、(Sr,Mg) ₂ P ₂ O ₇ :Eu ²⁺ 、α-Sr(PO ₃ ) ₂ ：Eu ²⁺ /Mn ²⁺ And the like. In view of the anionic structure, orthophosphate (PO) is mainly surrounded by more research and widely applied ₄ ) _n And triphosphates (P) ₂ O ₇ ) _n In the series, the matrix does not emit light, but has strong absorption in the vacuum ultraviolet-near ultraviolet region, which is exactly matched with the charge transfer between rare earth ions and coordinated oxygen, can effectively transfer energy to a light-emitting center and radiate the energy in the form of light. Recently, much research work in the related art has been conducted around doping modification based on the reported compounds, or research on a series of isomorphic compounds of a more mature matrix, and relatively rare work is conducted on exploring new matrix materials. The component proportion of a new compound from discovery to synthesis of a pure sample is determined by a large amount of experimental exploration; in addition, not all compounds are suitable as a host material for phosphor, and they are required to have good thermal stability and chemical stability, and high transmittance in the ultraviolet region for absorbing visible light, so those skilled in the art generally consider that the process of searching for a new host material is difficult.

The invention content is as follows:

the invention aims to provide a novel indium strontium orthophosphate fluorescent matrix material (also called as an indium strontium orthophosphate pyrophosphate composite fluorescent matrix material or an indium strontium phosphate pyrophosphate fluorescent matrix material).

The second purpose of the invention is to provide a simple process preparation method of the indium strontium orthophosphate fluorescent matrix material.

The third purpose of the invention is to provide an application method for preparing the fluorescent material by using the indium strontium orthophosphate fluorescent substrate material.

The fourth object of the present invention is to provide a fluorescent material obtained from the above-mentioned indium strontium orthophosphate fluorescent host material.

An indium strontium orthophosphate fluorescent matrix material with a chemical formula of Sr ₂ In(PO ₄ )(P ₂ O ₇ )。

The research of the invention finds that Sr ₂ In(PO ₄ )(P ₂ O ₇ ) Is a brand new compound, and the brand new compound is used as a substrate material for the rare earth fluorescent powder, thereby being beneficial to obtaining the fluorescent material with excellent luminescence property.

The crystal of the strontium indium orthophosphate fluorescent substrate material belongs to a monoclinic system, the space group is P121/c 1 (No. 14), the unit cell parameter is

β＝99.562(1)°

The unit cell of the indium strontium orthophosphate fluorescent substrate material has 17 crystallographic occupation: 1 In occupies 4e positions, 2 Sr occupies 24 e positions, 3P occupies 34 e positions, and 11O occupies 11 4e positions.

The invention also provides a preparation method for synthesizing the strontium indium pyrophosphate fluorescent matrix material, which comprises the steps of mixing a strontium source, an indium source and a phosphate source according to the stoichiometric ratio of the chemical formula to obtain a mixture, and sintering the mixture in multiple stages (sintering in N stages) to obtain the strontium pyrophosphate fluorescent matrix material; the number of stages of the multi-stage sintering is greater than or equal to 2 (N is an integer greater than or equal to 2);

in the multi-stage sintering process, the sintering temperature of the first stage is 600-700 ℃, and the sintering temperature of other stages (each sintering stage except the first stage in the multi-stage sintering process) is 1100-1200 ℃.

According to the preparation method, a strontium source, an indium source and a phosphate source are mixed according to the stoichiometric ratio of the chemical formula (Sr: in: P is 2.

The strontium source is strontium oxide or strontium salt which can be converted into strontium oxide; preferably at least one of strontium oxide, strontium carbonate, strontium nitrate and strontium sulfate.

The indium source is indium oxide or an indium compound which can be converted into indium oxide; preferably at least one of indium oxide, indium nitrate, indium carbonate, and indium hydroxide.

The phosphate source is at least one of phosphoric acid, diammonium hydrogen phosphate and ammonium dihydrogen phosphate.

The preparation method of the invention preferably adopts a wet chemical-solid phase synthesis method.

Preferably, a wet chemical method is adopted for mixing, and the steps are as follows: mixing the strontium source, the indium source and the phosphate source which are proportioned according to the stoichiometric ratio of the chemical formula, dissolving the mixture by acid liquor, adding water-soluble binder, and then evaporating the solvent in the system to obtain the mixture.

The acid solution is an aqueous solution of acid capable of dissolving raw materials (a strontium source, an indium source and a phosphate source); preferably a nitric acid solution.

The water-soluble binder is at least one of starch, dextrin, polyvinyl alcohol and carboxymethyl cellulose;

the dosage of the water-soluble adhesive is 2 to 3 times of the weight of the strontium source.

The research of the invention finds that the crystallization performance of the prepared material can be improved and the impure phase can be reduced by adopting the multi-stage sintering process in the temperature range.

Preferably, the number of stages of the multi-stage sintering process is greater than or equal to 2. For example, the multi-stage sintering includes a first stage sintering, a second stage sintering, an N stage sintering; and N is an integer not less than 2 (greater than or equal to).

In the multi-stage sintering process, after sintering in each stage is finished, cooling and grinding are carried out, and then sintering in the next stage is carried out.

Preferably, the first stage sintering time is 10 to 12 hours, and the other stage sintering (second to N stage sintering) time is 20 to 24 hours.

Preferably, the temperature increase rate in each stage is 3 to 5 ℃/min.

After the sintering in each stage is carried out for the time at the sintering temperature in a heat preservation way, the sintering is cooled to the room temperature along with the furnace, and the temperature is raised to the sintering temperature after grinding for carrying out the heat preservation sintering in the next stage; and cooling and grinding the sintered product until the last section is sintered to obtain the phosphate fluorescent matrix material for the indium-strontium-three-rare earth fluorescent powder.

The room temperature is, for example, 15 to 35 ℃.

Preferably, the mixture is subjected to first-stage sintering at the temperature of 600-700 ℃, then cooled to room temperature, ground and heated to the temperature of 1100-1200 ℃ for second-stage sintering, and the indium strontium orthophosphate fluorescent matrix material is obtained. Preferably, the time for the first stage sintering is 10-12h, and the time for the second stage sintering is 20-24h.

The preferable preparation method of the invention adopts a wet chemical-solid phase reaction method to prepare the indium strontium pyrophosphate orthophosphate fluorescent substrate material, and comprises the following steps: according to the weight percentage of Sr: in: the molar ratio of P is 2:1:3 weighing appropriate amount of SrCO ₃ 、In ₂ O ₃ And NH ₄ H ₂ PO ₄ Placing into a beaker, adding strong acid (such as nitric acid, etc.), heating and stirring to dissolve the raw materials, adding polyvinyl alcohol and deionized water (or other water with high chemical purity) after the solution is clarified, heating and stirring until completely evaporating, and grinding the dried material uniformly; sintering at 600-700 deg.C for the first stage, cooling to room temperature, grinding, sintering at 1100-1200 deg.C for the second stage, cooling, and grinding to obtain the final product. Under the sintering temperature interval and time, a pure-phase sample can be obtained, and the sample is melted when the sintering temperature is higher than the sintering temperature range, so that a single phase cannot be obtained; below this sintering temperature, a second phase appears and the XRD data for the temperature comparison is illustrated in the figure. The heating rate of the first stage sintering step is preferably 3-5 ℃/min; the heating rate of the second stage sintering step is preferably 3-5 ℃/min; the temperature of the sintering step in the first stage is preferably 600-700 ℃; the temperature of the second stage sintering step is preferably 1100-1200 ℃; the heat preservation time of the first stage sintering step is preferably 10 to 12 hours; the holding time of the second stage sintering step is preferably 20 to 24 hours.

By comparing the X-ray powder diffraction data of the matrix material with MDIjade 6.5 software, an international diffraction data center (ICDD) powder diffraction database (PDF-4 + 2011) and an Inorganic Crystal Structure Database (ICSD) show that the material belongs to a monoclinic system, C12/C1 (No. 15) space group. The inventor can determine that the matrix structure of the invention has 17 crystallographic place-holders in total by analyzing and refining the crystal structure by methods such as Fullprof software, rietveld full spectrum fitting and the like: 1 In occupies 4e positions, 2 Sr occupies 24 e positions, 3P occupies 34 e positions, and 11O occupies 11 4e positions, so that the substrate is determined to be a compound with a crystal structure and properties which are not reported yet.

The invention also provides application of the indium strontium orthophosphate fluorescent matrix material as a substrate material for preparing a fluorescent material.

Preferably, the fluorescent material is prepared by doping Sr and/or In the indium strontium orthophosphate fluorescent host material with fluorescent luminous ions.

More preferably, the fluorescent light-emitting ion is Dy ³⁺ And/or Tm ³⁺ 。

The invention also provides a fluorescent material with the chemical formula of Sr ₂ (In _1-x M _x )(PO ₄ )(P ₂ O ₇ ) (ii) a M is at least one of Tm and Dy;

x is 0.01 to 0.1; preferably 0.01 to 0.05; more preferably 0.03. The research of the invention finds that the white light LED material can be obtained by doping M, for example, by utilizing the co-doping of Tm and Dy.

The invention also comprises a preparation method of the fluorescent material, which is similar to the preparation method of the indium strontium pyrophosphate orthophosphate fluorescent matrix material. For example, the fluorescent material can be obtained by mixing the materials according to the stoichiometric ratio of the chemical formula of the fluorescent material and then performing the multi-stage sintering.

Preferably, the method is characterized by mixing materials by adopting the wet method and then matching with the multistage sintering.

The invention has the advantages of

1. The invention successfully prepares a novel phosphate compound which can be used as a fluorescent powder substrate material for the first time, wherein the phosphate compound contains indium element with the property of rare earth element, and the rare earth element enters into a substrate crystal lattice as an activation center, so the compound prepared by the invention can be used as a substrate material for fluorescent powder; the strontium indium phosphate matrix material with a unique structure prepared by the invention in the prior art is not reported. The process has the characteristics of simple preparation process and the like.

2. The invention innovatively provides a brand-new fluorescent material obtained by doping the brand-new fluorescent substrate material, and the fluorescent material has excellent luminous performance.

Description of the drawings:

FIG. 1 is a comparison of XRD patterns of example 1 and comparative examples 1-3;

the diffraction peaks not shown in FIG. 1 correspond to Sr of the present invention ₂ In(PO ₄ )(P ₂ O ₇ ) Diffraction peaks. As can be seen from the figure, the XRD patterns of the samples prepared in example 1 and comparative examples 1-3 all contain Sr ₂ In(PO ₄ )(P ₂ O ₇ ) Diffraction peaks, the products obtained in comparative examples 1 to 3 were mixed phases, and the product obtained in example 1 was Sr in the present invention ₂ In(PO ₄ )(P ₂ O ₇ ) A single phase composition sample of the phosphor matrix material.

FIG. 2 shows SrO-InO in which examples 1 and comparative examples 1 to 3 are _1.5 -PO _2.5 A ternary system partial phase diagram; wherein the composition of example 1 is designated 1 and the compositions of comparative examples 1-3 are designated 2, 3, 4;

the phase diagram is drawn in a composition triangle according to a phase law based on the phase analysis results in example 1 and comparative examples 1 to 3. In the figure, 1 shows SrIn in the invention ₂ (P ₂ O ₇ ) ₂ The matrix material is located at the composition point, and the components of comparative examples 1 to 3 are located in a two-phase region and a three-phase region near the point.

FIG. 3 is a comparison of XRD patterns of three samples of example 1, example 2 and example 3;

the product obtained in example 1 is a single phase with all diffraction peaks in the XRD pattern belonging to Sr ₂ In(PO ₄ )(P ₂ O ₇ ). As can be seen from FIG. 3, examples 2 and 3The diffraction peak of the prepared product is consistent with that of the diffraction peak of the example 1, no impurity peak appears, the products prepared in the examples 2 and 3 are all single-phase, and the Sr proves that ₂ In(PO ₄ )(P ₂ O ₇ ) Can synthesize pure phase with good crystallinity in the final burning temperature range of 1100-1200 ℃.

FIG. 4 comparison of XRD patterns of three samples of example 1, comparative example 4 and comparative example 5;

the product of example 1 is a single phase with all diffraction peaks in the XRD pattern belonging to Sr ₂ In(PO ₄ )(P ₂ O ₇ ). As can be seen from fig. 4, the diffraction peaks of the products prepared in comparative examples 4 and 5 were substantially identical to those of example 1, but a small amount of hetero-peaks appeared, and it was found that the products prepared in comparative examples 4 and 5 had a small amount of hetero-phase. The step of sectional sintering and the sintering holding time are proved to have obvious influence on the synthesis purity of the sample.

FIG. 5 shows the results of example 1 at room temperature of 400-2000cm ^-1 An infrared spectrum in the wavenumber range;

as can be seen, the low frequency part is positioned at 420-485cm ^-1 The three absorption peaks of the range are generated by the symmetric bending vibration of O-P-O; 544-630cm ^-1 The four absorption peaks of the range are caused by asymmetric bending vibration of O-P-O; the middle frequency part is located at 734.88cm ^-1 ；903.42cm ^-1 And 940.26cm ^-1 The peaks of (a) belong to the symmetric stretching vibration and the asymmetric stretching vibration of P-O-P respectively; at high frequency of 994.62cm ^-1 And 1014.32cm ^-1 The absorption peak of (2) is caused by asymmetric stretching vibration of P-O bond, and is 1073-1166 cm ^-1 Is caused by symmetric stretching vibration of O-P-O, and is located at 1195.26cm ^-1 And 1219.33cm ^-1 The peak is caused by the asymmetric stretching vibration of O-P-O. From the results of infrared spectroscopic analysis, sr ₂ In(PO ₄ )(P ₂ O ₇ ) Contains (P) ₂ O ₇ ) And (PO) ₄ ) A group.

FIG. 6 is a comparison of XRD patterns of four samples of example 1, example 4, example 5 and example 6;

EXAMPLE 1 preparation ofThe obtained product is a single phase, and all diffraction peaks in an XRD pattern belong to Sr ₂ In(PO ₄ )(P ₂ O ₇ ). As can be seen from fig. 6, the diffraction peaks of the products obtained in examples 4, 5, and 6 were identical in position to the diffraction peak of example 1, and no hetero-peak appeared, indicating that the products obtained in examples 4, 5, and 6 were single-phase.

FIG. 7 is a comparison of the XRD patterns of four samples, example 1, example 7, example 8, and example 9;

the product obtained in example 1 is a single phase with all diffraction peaks in the XRD pattern belonging to Sr ₂ In(PO ₄ )(P ₂ O ₇ ). As can be seen from fig. 7, the diffraction peaks of the products obtained in examples 7, 8 and 9 are identical to the diffraction peak of example 1 in position, and substantially no hetero-peak appears, indicating that the products obtained in examples 7, 8 and 9 are single-phase.

FIG. 8 is a comparison of the XRD patterns of four samples, example 1, example 10, example 11 and example 12;

the product of example 1 is a single phase with all diffraction peaks in the XRD pattern belonging to Sr ₂ In(PO ₄ )(P ₂ O ₇ ). As can be seen from fig. 7, the diffraction peaks of the products obtained in examples 10, 11, and 12 are identical in position to the diffraction peak of example 1, and there is substantially no hetero-peak, which indicates that the products obtained in examples 10, 11, and 12 are single-phase.

FIG. 9 shows Sr obtained in examples 4 to 6 ₂ (In _1-x Dy _x )(PO ₄ )(P ₂ O ₇ ) An excitation spectrum of the phosphor;

by fixing Dy with a characteristic emission wavelength of 573nm and measuring excitation spectra of the phosphors obtained in examples 4 to 6, it can be seen from the figure that an excitation peak appears in the range of 250 to 500nm, and a narrow peak between 250 and 500nm is Dy ³⁺ F-f transition characteristic excitation peak of the ion; it is clear that the intensity of the excitation spectrum of the phosphor prepared in example 6 is higher than that of the phosphors prepared in examples 4 and 5.

FIG. 10 shows Sr produced in examples 4 to 6 ₂ (In _1-x Dy _x )(PO ₄ )(P ₂ O ₇ ) Emission spectrogram of the fluorescent powder;

as shown in FIG. 9, when the emission spectra of the phosphors obtained in examples 4 to 6 were measured based on the characteristics of the excitation peaks of examples 4 to 6, which were fixed at an excitation wavelength of 346nm, it was found that emission peaks at 482nm, 573nm and 671nm were observed in the range of 450 to 700nm, and that the emission peak of yellow light at 573nm was the strongest as the doping concentration increased. When the yellow emission peak is higher in intensity than the blue emission peak and predominates, dy is known to be present ³⁺ Occupy a position offset from the center of symmetry to ⁴ F _9/2 → ⁶ H _15/2 The transmission is dominant. It is clear that the intensity of the emission spectrum of the phosphor prepared in example 6 is higher than that of the phosphors prepared in examples 4 and 5.

FIG. 11 shows Sr obtained in examples 7 to 9 ₂ (In _1-x Tm _x )(PO ₄ )(P ₂ O ₇ ) Excitation spectrum of the phosphor;

by fixing the characteristic emission wavelength of Tm to 458nm and measuring the excitation spectra of the phosphors prepared in examples 7 to 9, it can be seen from the figure that an excitation peak appears at 356nm in the range of 300 to 400nm, belonging to Tm ³⁺ F-f transition characteristic excitation peak of ion; it is clear that the intensity of the excitation spectrum of the phosphor prepared in example 9 is higher than that of the phosphors prepared in examples 7 and 8.

FIG. 12 shows Sr in examples 7 to 9 ₂ (In _1-x Tm _x )(PO ₄ )(P ₂ O ₇ ) Emission spectrogram of the fluorescent powder;

the emission spectra of the phosphors prepared in examples 7 to 9 were measured at a fixed excitation wavelength of 356nm based on the characteristics of the excitation peaks of examples 7 to 9 in FIG. 11, and it can be seen from the graph that an emission peak at 458nm occurs in the range of 400 to 500nm, which is attributed to ³ H ₆ → ¹ D ₂ And emits light and increases with increasing doping concentration. It is clear that the intensity of the emission spectrum of the phosphor prepared in example 9 is higher than that of the phosphors prepared in examples 7 and 8.

The requirements of the near ultraviolet LED chip on the fluorescent powder are as follows: the optimal excitation wavelength is in the range of 350-400 nm. As can be seen from fig. 8 to 11, the phosphors prepared in examples 4 to 6 can be applied to a yellow LED excited by near ultraviolet, and the phosphors prepared in examples 7 to 9 can be applied to a blue LED excited by near ultraviolet.

FIG. 13 is a chromaticity coordinate diagram of phosphors prepared in examples 6 and 9;

the chromaticity coordinates of the phosphor were analyzed by CIE chromaticity software, and it was confirmed that the chromaticity coordinates of example 6 and example 9 were (0.3584, 0.3639), (0.1486, 0.0465), respectively. It can be seen that example 6 is located in the yellow-white region and example 9 is located in the blue region.

FIG. 14 is Sr produced in example 5 ₂ In _0.98 Dy _0.02 (PO ₄ )(P ₂ O ₇ ) Excitation spectrum of phosphor and Sr obtained in example 8 ₂ In _0.98 Tm _0.02 (PO ₄ )(P ₂ O ₇ ) An excitation spectrogram and an emission spectrogram of the fluorescent powder;

as is clear from FIG. 14, tm is a constant overlap between the excitation spectrum of example 5 and the excitation spectrum and the emission spectrum of example 8 ³⁺ Characteristic excitation peak and Dy at 356nm ³⁺ The overlap of the characteristic excitation peaks at 346nm and 361nm indicates that the two activator ions can be excited by the same wavelength radiation source; and Tm are ³⁺ Characteristic emission peak at 458nm and Dy ³⁺ The overlap of characteristic excitation peaks at 451nm, evidencing Tm ³⁺ The energy released by the excited transition can be Dy ³⁺ And (4) absorbing the waste water. Theoretically, dy ³⁺ /Tm ³⁺ Co-doped Sr ₂ In(PO ₄ )(P ₂ O ₇ ) The fluorescent powder can realize Tm ³⁺ →Dy ³⁺ Energy transfer of (2).

At present, the white light LED is mainly realized by combining an LED chip and phosphor, and the phosphor converts part or all of the short wavelength light emitted from the chip into visible light, and finally compounds the visible light into white light. The white light can be obtained by adjusting the intensity of the blue light and the yellow light to a proper proportion. We then co-dope Dy and Tm in different concentrations into Sr ₂ In(PO ₄ )(P ₂ O ₇ ) FluorescenceAnd (3) powder matrix, and the single phosphate matrix white light fluorescent powder is successfully prepared.

FIG. 15 shows Sr in examples 10 to 12 ₂ (In _0.99-x Tm _0.01 Dy _x )(PO ₄ )(P ₂ O ₇ ) Emission spectrogram of the fluorescent powder;

according to Dy in FIG. 14 ³⁺ /Tm ³⁺ The excitation peak is characterized by fixing the excitation wavelength to a suitable value: 351nm, the emission spectra of the phosphors obtained in examples 10 to 12 were measured, and it can be seen from the graph that emission peaks appeared at 458nm,482nm, 573nm and 671nm in the range of 400 to 700nm, and that 482nm, 573nm and 671nm are Dy ³⁺ Characteristic emission peak of (1), intensity of peak following Dy ³⁺ The doping concentration increases; wherein 458nm belongs to Tm ³⁺ Characteristic emission peak of (1), intensity of peak following Dy ³⁺ The doping concentration increases and decreases. From Tm ³⁺ The occurrence of quenching phenomenon in emission intensity can be judged, tm ³⁺ →Dy ³⁺ There is indeed energy transfer between them.

FIG. 16 is a chromaticity coordinate graph of phosphors prepared in examples 10, 11 and 12;

the chromaticity coordinates of the phosphors were analyzed by CIE chromaticity software to determine (0.3153, 0.2984), (0.334, 0.3312) and (0.3626, 0.3699) for examples 10, 11 and 12, respectively. It is known that Dy is accompanied by Dy ³⁺ /Tm ³⁺ Dy in co-doped fluorescent powder ³⁺ Specific gravity of the concentration increased, sr ₂ (In _0.99-x Tm _0.01 Dy _x )(PO ₄ )(P ₂ O ₇ ) The light emitted by the phosphor can be transited from a cold white light (example 10) to a warm white light (example 12) region, and the use requirement of the phosphor for a white light LED can be met.

The specific implementation mode is as follows:

the following examples are intended to further illustrate the invention without limiting it.

Example 1: sr ₂ In(PO ₄ )(P ₂ O ₇ ) Preparation of phosphor matrix

Weighing SrCO ₃ 、In ₂ O ₃ 、NH ₄ H ₂ PO ₄ Preparing materials according to the element stoichiometric ratio (the element ratio of Sr, in and P is 2 ₃ 2 times of the weight), heating and stirring until completely evaporating, placing the beaker in a drying oven for drying, and grinding uniformly; and then two-step final sintering is carried out (the sintering temperature of the first step is 600 ℃, the temperature is kept for 12 hours, then the temperature is cooled to the room temperature along with the furnace, the grinding is carried out for 10 minutes, the sintering temperature of the second step is 1150 ℃, the temperature is kept for 24 hours, then the temperature is cooled to the room temperature along with the furnace, the sintering temperature rise rate of the first step is 3 ℃/minute, and the sintering temperature rise rate of the second step is 5 ℃/minute). Taking out the fired sample and grinding to obtain Sr ₂ In(PO ₄ )(P ₂ O ₇ ) A phosphor matrix. After structure refinement, the unit cell parameters are determined as follows:

β＝99.562(1)°，Z＝4。

comparative example 1: sr: in: the P molar ratio is 1.6:3:5.4 preparation of samples

SrCO ₃ 、In ₂ O ₃ 、NH ₄ H ₂ PO ₄ According to the element ratio of Sr, in and P of 1.6:3:5.4 batching, the rest steps are the same as the example 1.

Comparative example 2: sr: in: the P molar ratio is 1.9:3.1:5 preparation of the sample

SrCO ₃ 、In ₂ O ₃ 、NH ₄ H ₂ PO ₄ According to the element ratio of Sr, in and P of 1.9:3.1:5, preparing materials, and the rest steps are the same as the example 1.

Comparative example 3: sr: in: the P molar ratio is 4.2:1.1:4.7 preparation of samples

SrCO ₃ 、In ₂ O ₃ 、NH ₄ H ₂ PO ₄ According to the element ratio of Sr, in and P of 4.2:1.1:4.7 compounding, and the rest steps are the same as in example 1.

Comparative example 4: sr: in: the molar ratio of P is 2:1:3 preparation of one-stage sintered sample

SrCO ₃ 、In ₂ O ₃ 、NH ₄ H ₂ PO ₄ According to the element ratio of Sr, in and P as 2:1:3, proportioning, only carrying out one-step final firing (the sintering temperature is 1150 ℃, the heat preservation is 24 hours, the sintering temperature rise rate is 5 ℃/minute), and the rest steps are the same as the example 1.

Comparative example 5: sr: in: the molar ratio of P is 2:1:3 preparation of samples incubated for 12 hours

SrCO ₃ 、In ₂ O ₃ 、NH ₄ H ₂ PO ₄ According to the element ratio of Sr, in and P as 2:1:3, proportioning, wherein the heat preservation time of the two-step sintering is 12 hours, and the rest steps are the same as the example 1.

Example 2: sr ₂ In(PO ₄ )(P ₂ O ₇ ) Preparation of phosphor matrix (Final firing temperature 1100 ℃ C.)

SrCO ₃ 、In ₂ O ₃ 、NH ₄ H ₂ PO ₄ According to the element ratio of Sr, in and P as 2:1:3 proportioning, the sintering temperature of the second step is 1100 ℃, and the rest steps are the same as the example 1.

Example 3: sr (strontium) ₂ In(PO ₄ )(P ₂ O ₇ ) Preparation of phosphor matrix (Final firing temperature 1200 ℃ C.)

SrCO ₃ 、In ₂ O ₃ 、NH ₄ H ₂ PO ₄ According to the element ratio of Sr, in and P as 2:1:3, proportioning, and the sintering temperature of the second step is 1200 ℃, and the rest steps are the same as the example 1.

Example 4: sr ₂ In _0.99 Dy _0.01 (PO ₄ )(P ₂ O ₇ ) Preparation of phosphor

SrCO ₃ 、In ₂ O ₃ 、Dy ₂ O ₃ 、NH ₄ H ₂ PO ₄ According to the element ratio of Sr, in, dy and P of 2:0.99:0.01:3, preparing materials, and the rest steps are the same as the example 1.

Example 5: sr ₂ In _0.98 Dy _0.02 (PO ₄ )(P ₂ O ₇ ) Preparation of phosphor

SrCO ₃ 、In ₂ O ₃ 、Dy ₂ O ₃ 、NH ₄ H ₂ PO ₄ According to the element ratio of Sr, in, dy and P as 2:0.98:0.02:3, preparing materials, and the rest steps are the same as the example 1.

Example 6: sr (strontium) ₂ In _0.97 Dy _0.03 (PO ₄ )(P ₂ O ₇ ) Preparation of phosphor

SrCO ₃ 、In ₂ O ₃ 、Dy ₂ O ₃ 、NH ₄ H ₂ PO ₄ According to the element ratio of Sr, in, dy and P as 2:0.97:0.03:3, preparing materials, and the rest steps are the same as the example 1.

Example 7: sr (strontium) ₂ In _0.99 Tm _0.01 (PO ₄ )(P ₂ O ₇ ) Preparation of phosphor

SrCO ₃ 、In ₂ O ₃ 、Tm ₂ O ₃ 、NH ₄ H ₂ PO ₄ According to the element ratio of Sr, in, tm and P as 2:0.99:0.01:3, preparing materials, and the rest steps are the same as the example 1.

Example 8: sr ₂ In _0.98 Tm _0.02 (PO ₄ )(P ₂ O ₇ ) Preparation of phosphor

SrCO ₃ 、In ₂ O ₃ 、Tm ₂ O ₃ 、NH ₄ H ₂ PO ₄ According to the element ratio of Sr, in, tm and P as 2:0.98:0.02:3, preparing materials, and the rest steps are the same as the example 1.

Example 9: sr ₂ In _0.97 Tm _0.03 (PO ₄ )(P ₂ O ₇ ) Preparation of phosphor

SrCO ₃ 、In ₂ O ₃ 、Tm ₂ O ₃ 、NH ₄ H ₂ PO ₄ According to the element ratio of Sr, in, tm and P as 2:0.97:0.03:3, preparing materials, and the rest steps are the same as the example 1.

Example 10: sr (strontium) ₂ In _0.98 Dy _0.01 Tm _0.01 (PO ₄ )(P ₂ O ₇ ) Preparation of phosphor

SrCO ₃ 、In ₂ O ₃ 、Dy ₂ O ₃ 、Tm ₂ O ₃ 、NH ₄ H ₂ PO ₄ According to the element ratio of Sr, in, dy, tm and P of 2:0.98:0.01:0.01:3, preparing materials, and the rest steps are the same as the example 1.

Example 11: sr ₂ In _0.97 Dy _0.02 Tm _0.01 (PO ₄ )(P ₂ O ₇ ) Preparation of phosphor

SrCO ₃ 、In ₂ O ₃ 、Dy ₂ O ₃ 、Tm ₂ O ₃ 、NH ₄ H ₂ PO ₄ According to the element ratio of Sr, in, dy, tm and P as 2:0.97:0.02:0.01:3, preparing materials, and the rest steps are the same as the example 1.

Example 12: sr ₂ In _0.96 Dy _0.03 Tm _0.01 (PO ₄ )(P ₂ O ₇ ) Preparation of phosphor

SrCO ₃ 、In ₂ O ₃ 、Dy ₂ O ₃ 、Tm ₂ O ₃ 、NH ₄ H ₂ PO ₄ According to the element ratio of Sr, in, dy, tm and P as 2:0.96:0.03:0.01:3, preparing materials, and the rest steps are the same as the example 1.

Claims

1. The indium strontium orthophosphate fluorescent substrate material is characterized in that the chemical formula is Sr ₂ In(PO ₄ )(P ₂ O ₇ )。

2. The indium strontium orthophosphate fluorescent host material as claimed in claim 1, characterized in that it belongs to monoclinic system and has a space group ofP 1 21/c 1 (No. 14), unit cell parameters a = 6.5832 (3) a, b = 6.8984 (3) a, c = 19.8129 (10) a, β = 99.562 (1) °.

3. The indium strontium orthophosphate fluorescent host material of claim 2, characterized in that the indium strontium orthophosphate fluorescent host material has 17 crystallographic space occupation in total: 1 In occupies 4e positions, 2 Sr occupies 24 e positions, 3P occupies 34 e positions, and 11O occupies 11 4e positions.

4. A preparation method of the strontium indium orthophosphate fluorescent matrix material according to any one of claims 1 to 3, characterized by mixing a strontium source, an indium source and a phosphate source according to the stoichiometric ratio of the chemical formula to obtain a mixture, and sintering the mixture in multiple stages to obtain the strontium orthophosphate fluorescent matrix material; the number of stages of the multi-stage sintering is greater than or equal to 2;

in the multi-stage sintering process, the sintering temperature of the first stage is 600-700 ℃, and the sintering temperature of the other stages is 1100-1200 ℃.

5. The method for preparing indium strontium orthophosphate fluorescent host material according to claim 4, characterized in that said strontium source is strontium oxide or strontium salt convertible to strontium oxide;

the indium source is indium oxide or an indium compound which can be converted into indium oxide;

6. The method for preparing the indium strontium pyrophosphate fluorescent host material according to claim 5, wherein the strontium source is at least one of strontium oxide, strontium carbonate, strontium nitrate and strontium sulfate;

the indium source is at least one of indium oxide, indium nitrate, indium carbonate and indium hydroxide.

7. The method for preparing the indium strontium orthophosphate fluorescent substrate material as claimed in claim 4, characterized in that the wet chemical method is adopted for mixing, and the steps are as follows: mixing the strontium source, the indium source and the phosphate source which are proportioned according to the stoichiometric ratio of the chemical formula, dissolving the mixture by acid liquor, adding water-soluble binder, and then evaporating the solvent in the system to obtain the mixture.

8. The method of claim 7, wherein the water-soluble binder is at least one of starch, dextrin, polyvinyl alcohol, and carboxymethyl cellulose;

the dosage of the water-soluble binder is 2 to 3 times of the weight of the strontium source.

9. The method of preparing the indium strontium pyrophosphate fluorescent host material according to claim 4, wherein in the multi-stage sintering process, after each stage of sintering is completed, the sintering is carried out in the next stage after cooling and grinding.

10. The method for preparing the indium strontium orthophosphate fluorescent host material of claim 9, characterized in that the sintering time of the first stage is 10-12 hours and the sintering time of the other stages is 20-24 hours.

11. The method for preparing the indium strontium orthophosphate fluorescent host material as claimed in claim 9, wherein the temperature rise rate in each stage is 3 to 5 ℃/min.

12. The application of the strontium indium orthophosphate fluorescent matrix material as defined In any one of claims 1 to 3 or the strontium indium orthophosphate fluorescent matrix material prepared by the preparation method as defined In any one of claims 4 to 11 is characterized In that In the strontium indium orthophosphate fluorescent matrix material is doped by adopting fluorescent luminous ions to prepare a fluorescent material; the fluorescent luminous ion is Dy ³⁺ And/or Tm ³⁺ 。

13. A fluorescent material is characterized in that the chemical formula is Sr ₂ (In _1-x M _x )(PO ₄ )(P ₂ O ₇ ) (ii) a M is at least one of Tm and Dy; x is 0.01 to 0.1.

14. The phosphor of claim 13, wherein x is 0.03.