CN110938427A

CN110938427A - Rare earth metal doped alkaline earth metal silicate material and its preparation method, application and light-emitting device

Info

Publication number: CN110938427A
Application number: CN201911200907.1A
Authority: CN
Inventors: 李玲; 徐泽凤; 刘晓光
Original assignee: Hubei University
Current assignee: Hubei University
Priority date: 2019-11-29
Filing date: 2019-11-29
Publication date: 2020-03-31

Abstract

The invention belongs to the technical field of inorganic luminescent materials, and particularly relates to a rare earth metal doped alkaline earth metal silicate material, a preparation method and application thereof, and a luminescent device. The silicate material is any one or mixture of more of rare earth metal doped alkaline earth metal silicate, wherein: the chemical general formula of the alkaline earth metal silicate is M_xR_4‑xSi₂O₇Y₂M is Ca, Sr or Ba, R is Ca, Sr or Ba, x is more than or equal to 1 and less than or equal to 4; y is any one or two of F, Cl or Br; the rare earth metal Re is Eu^3+/2+At least one of Ce or Sm; in the rare earth metal doped alkaline earth metal silicate, the molar ratio of the rare earth metal to the alkaline earth metal silicate is more than 0 and less than 0.1. The various silicate materials provided by the invention are doped with rare earth ions Eu^3+/2+、Ce³⁺、Sm³⁺At least one ofThe rare earth metal doped alkaline earth metal silicate material has the advantages of good luminous performance, high luminous efficiency, capability of realizing white light illumination and the like.

Description

Rare earth metal doped alkaline earth metal silicate material, preparation method and application thereof, and light-emitting device

Technical Field

The invention belongs to the technical field of inorganic luminescent materials, and particularly relates to a rare earth metal doped alkaline earth metal silicate material, a preparation method and application thereof, and a luminescent device.

Background

Conventional rare earth phosphors consist of oxynitride compositions, phosphate compositions, aluminate compositions, sulfide compositions, silicate compositions, etc., in which: the nitrogen oxide composition has the defects of narrow emission peak, harsh synthesis conditions, high cost of synthetic raw materials and the like; the nitride composition can emit green, yellow and red lights after being excited, but the nitride composition is expensive to prepare because it needs to be synthesized at high temperature and high pressure and the raw materials are expensive, thereby limiting its commercial use; phosphate compositions are not efficient in light emission, are moisture sensitive, and are susceptible to moisture; usually, the aluminate composition is a YAG composition, which has high Light conversion efficiency and is the most widely used composition at present, but has the disadvantages of narrow excitation band, no red emission, and low color rendering, and cannot be used alone to manufacture a Light emitting Diode (Light emitting Diode) LED with high color rendering index; sulfide compositions are chemically unstable, readily decomposed, and more readily decomposed when exposed to moisture or ultraviolet radiation.

The conventional rare earth phosphors are also composed of silicate compositions, and the compositions using silicate as a matrix have the advantages of wide emission spectrum, stable chemical properties, and the like, and are paid attention by researchers. In the previous research work, silicate compositions capable of emitting green light, yellow light and orange light have been prepared, but the silicate compositions have the characteristics of single color development, low color development performance and the like after being doped with rare earth ions, so that novel silicate compositions with various luminescent colors and high color purity and color development degree need to be researched.

Disclosure of Invention

In order to solve the defects of the prior art, the invention provides a rare earth metal doped alkaline earth metal silicate material, a preparation method, application and a light-emitting device thereof, so as to overcome the technical problems of single light-emitting color, low color purity and color rendering index and the like of the existing material.

The technical scheme provided by the invention is as follows:

a rare earth metal doped alkaline earth silicate material which is a mixture of any one or more of rare earth metal doped alkaline earth silicates wherein:

the chemical general formula of the alkaline earth metal silicate is M_xR_4-xSi₂O₇Y₂M is Ca, Sr or Ba, R is Ca, Sr or Ba, x is more than or equal to 1 and less than or equal to 4; y is any one or two of F, Cl or Br;

the rare earth metal Re is Eu^3+/2+At least one of Ce or Sm;

in the rare earth metal doped alkaline earth metal silicate, the molar ratio of the rare earth metal to the alkaline earth metal silicate is more than 0 and less than 0.1.

The rare earth metal doped alkaline earth metal silicate material provided by the technical scheme can be a pure phase of a single rare earth metal doped alkaline earth metal silicate or a composition of pure phases of a plurality of rare earth metal doped alkaline earth metal silicates.

The various rare earth metal doped alkaline earth metal silicate materials provided by the technical scheme are doped with rare earth ions Eu^3+/2+、Ce³⁺、Sm³⁺The mole fraction of the rare earth ions relative to the silicate is more than 0 and less than 0.1, so that compared with the traditional single-doped rare earth ion composition, the rare earth metal-doped alkaline earth metal silicate material has good luminescence performance and high luminescence efficiency, and finally can realize white light illumination.

In particular, the alkaline earth metal silicate is selected from Ca_1.25Sr_2.75Si₂O₇FCl、Ca₂Sr₂Si₂O₇FBr、Ca₃Sr₁Si₂O₇FCl、Ca₃Sr₁Si₂O₇FBr、Ca_1.5Sr_2.5Si₂O₇F_2、Sr₄Si₂O₇FCl or Sr₄Si₂O₇Br₂Any one of them.

Specifically, the position of the characteristic peak of the X-ray diffraction peak of the rare earth metal doped alkaline earth metal silicate on 2 theta is composed of: 11.97 °,16.80 °,19.28 °, 24.16 °,27.39 °,29.09 °,31.14 °,39.10 °, 44.99 °, 48.26 °,49.98 °,52.82 °.

In the various rare earth metal doped alkaline earth metal silicate materials provided by the invention, the composition of a single pure phase or a plurality of pure phases has basically consistent position composition of the characteristic peak of an X-ray diffraction peak on 2 theta.

In particular, the rare earth metal doped alkaline earth metal silicate has a unit cell volume of

The crystal system of the doped silicate is a monoclinic system; the space point group of the doped silicate is P121/C1.

In the rare earth metal doped alkaline earth metal silicate materials provided by the invention, various pure phases have the same crystal system structure and space point group and have basically consistent unit cell volume.

Specifically, the excitation wavelength range of the rare earth metal doped alkaline earth metal silicate material is 254nm-400 nm.

Specifically, the emission wavelength range of the rare earth metal doped alkaline earth metal silicate material is 400nm-750nm, and the light is blue light, green light, purple light, white light or red light.

The rare earth metal doped alkaline earth metal silicate material provided by the invention has the excitation wavelength range of 250nm-400nm and the emission peak position of 400nm-500nm, so that the rare earth metal doped alkaline earth metal silicate material can emit blue light and red light simultaneously, and the characteristics of wide light emitting area and adjustable light emitting color are realized.

The invention also provides a preparation method of the rare earth metal doped alkaline earth metal silicate material, which comprises the following steps:

preparing a rare earth metal doped alkaline earth metal silicate material by adopting a high-temperature solid-phase synthesis method;

or synthesizing the rare earth metal doped alkaline earth metal silicate material by adopting a combustion method;

or synthesizing the rare earth metal doped alkaline earth metal silicate material by adopting a sol-gel method.

Specifically, the high-temperature solid-phase synthesis method comprises the following steps:

s1, weighing the first raw material CaCO₃、SrCO₃Or BaCO₃At least one of them, weighing the second raw material CaCl₂、CaF₂、CaBr₂At least one of the three raw materials Eu is weighed₂O₃、CeO₂、Sm₂O₃And is called SiO₂Grinding after uniformly mixing to obtain a ground sample;

s2, placing the ground sample obtained in the step 1) in a high-temperature furnace, calcining in the atmosphere of air or reducing gas, cooling after calcining, and grinding again to obtain a precursor;

s3, placing the precursor obtained in the step 2) into a high-temperature furnace, and calcining the precursor in the atmosphere of air or reducing gas to obtain the rare earth metal doped alkaline earth metal silicate material, wherein:

the first raw material, SiO₂The molar ratio of the second raw material to the second raw material is 3.9-4.1: 1.9-2.1: 0.9-1.1;

the total molar weight of rare earth metals and SiO in the third raw material₂Is greater than 0 and less than 0.05.

In step S2, the original gas is a mixed gas of hydrogen and nitrogen, wherein the volume fraction of the hydrogen is 5-10%; the calcination way is that the temperature is increased to 1200-1600 ℃ at the speed of 5-10 ℃ per minute, and the calcination time is 4-6 h;

in step S3, the calcination manner is increased to 1200-1600 ℃ at a rate of 2-5 ℃ per minute, the calcination time is 5-10 h, and the calcination temperature in step S3 is higher than the calcination temperature in step S2.

The technical scheme has the advantages that the material with high purity, few surface defects and strong luminescence property can be obtained.

Specifically, the combustion method comprises the following steps:

s1, weighing the first raw material CaCO₃、SrCO₃Or BaCO₃At least one of them, weighing the second raw material CaF₂、CaCl₂Or CaBr₂At least one of the three raw materials Eu is weighed₂O₃、CeO₂Or Sm₂O₃At least one of them is named as SiO2 and C₂H₅NO₂And HNO₃；

S2, adding the raw materials weighed in the step S1 into water, heating to evaporate water, and obtaining a colloidal material;

s3, heating the colloidal material obtained in the step S2 until the colloidal material is self-ignited, and continuing heating until the combustion reaction is finished to obtain the rare earth metal doped alkaline earth metal silicate material, wherein:

the total molar weight of rare earth metals and SiO in the third raw material₂Molar ratio of molar mass greater than 0 and less than 0.05, C₂H₅NO₂The molar ratio of the first raw material to the first raw material is 1: 2.1-0.9: 1.8, and the molar ratio of HNO3 to the total molar weight of the rare earth metals in the third raw material is 0.9: 0.96-1: 1.2-0.9: 0.95.

In the step S2, in the step S2, the using amount ratio of the raw materials and the water in the step 1) is 1: 3-1: 1.6g/ml, and the heating temperature is 95-100 ℃;

in step S3, the heating temperature after spontaneous combustion is 1150-1250 ℃;

the technical scheme has the advantages that the nano material with small size and high purity can be obtained.

Specifically, the sol-gel method comprises the following steps:

s1, weighing the first raw material CaNO₃、SrNO₃Or BaNO₃At least one of them, weighing the second raw material CaF₂、CaCl₂Or CaBr₂At least one of the three raw materials Eu is weighed₂O₃、CeO₂Or Sm₂O₃And is called SiO₂；

S2, weighing in the step S1, fully mixing with the citric acid aqueous solution, heating and stirring to form gel;

s3, drying the gel obtained in the step S2 into dry gel, and then calcining the dry gel at high temperature to obtain the rare earth metal doped alkaline earth metal silicate material, wherein:

the total molar weight of rare earth metals and SiO in the third raw material₂The molar ratio of the molar amounts is greater than 0 and less than 0.05.

In the step S2, the concentration of the citric acid aqueous solution is 0.5-2.0 ml/mol, the dosage ratio of the raw materials in the step 1) to the citric acid aqueous solution is 1: 2.6-1: 1.5g/ml, and the heating temperature is 95-100 ℃;

in step S3, the drying temperature is 115-125 ℃, and the calcining temperature is 1200-1400 ℃.

The technical scheme has the advantages of small and uniform size of the synthesized crystal.

The invention also provides the application of the rare earth metal doped alkaline earth metal silicate material as a luminescent material.

Further, the fluorescent material is used as a luminescent material for anti-counterfeiting.

The rare earth metal doped alkaline earth metal silicate material provided by the invention is doped with rare earth ions Eu^3+/2+、Ce³ ⁺、Sm³⁺At least one of which emits red light when the excitation wavelength is 254nm and emits blue light when the excitation wavelength is 365nm, so that the rare earth metal doped alkaline earth metal silicate material can play the role of anti-counterfeiting when being smeared on the band identification material

The invention also provides a light-emitting device which comprises a light-emitting diode, wherein the light-emitting diode is provided with a gallium nitride semiconductor, and the light-emitting device is characterized in that a light-emitting layer is arranged on the gallium nitride semiconductor, and the material of the light-emitting layer is selected from the rare earth metal doped alkaline earth metal silicate material provided by the invention.

The light-emitting device provided by the invention emits blue light, green light, purple light, white light or red light within the wavelength range of 400nm-750 nm.

Drawings

FIG. 1 schematically shows a unit cell structure of a silicate composition in an embodiment of the invention;

FIG. 2 schematically shows an X-ray diffraction pattern of a silicate composition in an example of the invention;

FIG. 3a shows schematically a fluorescence property diagram of a silicate doped Eu ion composition according to an exemplary embodiment of the present invention at an excitation wavelength of 254 nm;

FIG. 3b shows schematically a fluorescence property diagram of a silicate doped Eu ion composition according to an embodiment of the present invention at an excitation wavelength of 350 nm;

FIG. 3c is a graph schematically showing the fluorescence properties of compositions of silicate-doped Eu ions according to an exemplary embodiment of the present invention at a detection wavelength of 440 nm;

FIG. 3d is a graph schematically showing the fluorescence properties at a detection wavelength of 621nm of a composition of silicate-doped Eu ions according to an embodiment of the present invention;

FIG. 3e schematically shows a fluorescence property diagram of a silicate composition at excitation wavelengths of 350nm, 365nm, 380nm and 400nm, respectively, in an example of the invention;

figure 4 schematically shows a flow diagram of a method for preparing a silicate composition in an embodiment of the invention.

Detailed Description

The principles and features of this invention are described below in conjunction with examples which are set forth to illustrate, but are not to be construed to limit the scope of the invention.

The embodiment of the invention provides a rare earth metal doped alkaline earth metal silicate material which is a mixture of any one or more of rare earth metal doped alkaline earth metal silicates. The chemical general formula of the alkaline earth metal silicate is M_xR_4- _xSi₂O₇Y₂M is Ca, Sr or Ba, R is Ca, Sr or Ba, x is more than or equal to 1 and less than or equal to 4; y is either F, Cl or Br or both. The rare earth metal Re is Eu^3+/2+At least one of Ce or Sm. The rare earth metal doped alkaline earthIn the metal silicate, the molar ratio of the rare earth metal to the alkaline earth metal silicate is more than 0 and less than 0.1.

The alkaline earth metal silicate used in the present invention is selected from Ca_1.25Sr_2.75Si₂O₇FCl、Ca₂Sr₂Si₂O₇FBr、Ca₃Sr₁Si₂O₇FCl、Ca₃Sr₁Si₂O₇FBr、Ca_1.5Sr_2.5Si₂O₇F₂、Sr₄Si₂O₇FCl or Sr₄Si₂O₇Br₂The above silicate Ca₂Sr₂Si₂O₇FBr unit cell structure referring to fig. 1, fig. 1 schematically shows a unit cell structure diagram of an alkaline earth metal doped silicic acid, wherein 1 silicon atom is surrounded by 4 oxygen atoms, and 1 silicon atom and 4 oxygen atoms form a tetrahedral structure; the tetrahedral structure consisting of silicon and oxygen atoms is connected to form a three-dimensional framework structure of the crystal, and calcium atoms are distributed in the three-dimensional framework structure; and 1 fluorine atom and 6 oxygen atoms are arranged around 1 calcium atom, so that the 1 calcium atom, the 1 fluorine atom and the 6 oxygen atoms form a polyhedral structure; in the above polyhedral structure, the calcium atom can be partially or completely substituted with a strontium atom or a barium atom.

The various rare earth metal doped alkaline earth metal silicates provided by the present invention have a unit cell volume of

The unit cell belongs to monoclinic system, and the space point group is P121/C1.

Referring to FIG. 2, FIG. 2 shows a rare earth metal doped alkaline earth metal silicate material Ca according to the present invention_2.75Sr_1.25Si₂O₇F₂:1％Eu³⁺The lower part of the X-ray diffraction diagram is Ca_2.75Sr_1.25Si₂O₇F₂The JCPDS of (1). Wherein, Ca_2.75Sr_1.25Si₂O₇F₂:1％Eu³⁺Position group of X-ray diffraction peak of (2 theta)The method comprises the following steps: 11.97 °,16.80 °,19.28 °, 24.16 °,27.39 °,29.09 °,31.14 °,39.10 °, 44.99 °, 48.26 °,49.98 °,52.82 °, and Ca_2.75Sr_1.25Si₂O₇F₂Is substantially close to the JCPDS of (a).

Referring to FIG. 3a, FIG. 3a schematically shows Ca provided in example 1 of the present invention_2.75Sr_1.25Si₂O₇F₂:1％Eu³⁺Fluorescence property at excitation wavelength of 254 nm. As can be seen from FIG. 3a, the emission peak positions obtained at an excitation wavelength of 254nm consist of a blue-green region in the range of 350nm to 500nm and a red-orange region in the range of 570nm to 750 nm.

Referring to FIG. 3b, FIG. 3b schematically shows a silicate composition Ca according to an embodiment of the present invention_2.75Sr_1.25Si₂O₇F₂：1％Eu³⁺Fluorescence property plot at 350nm excitation wavelength. As can be seen from FIG. 3b, the emission peak positions obtained at an excitation wavelength of 350nm consist of a blue-green region in the range of 360nm to 550nm and a red-orange region in the range of 560nm to 750 nm.

Referring to FIG. 3c, FIG. 3c schematically shows a rare earth ion-doped silicate composition Ca according to an embodiment of the present invention_2.75Sr_1.25Si₂O₇F₂：1％Eu³⁺Fluorescence property plot at 440nm detection wavelength. As can be seen from FIG. 3c, the excitation wavelength composition of the silicate composition is an excitation peak centered at 252nm in the range of 225nm to 320nm and an excitation peak centered at 365nm in the range of 320nm to 425nm, which correspond to FIG. 3a and FIG. 3b, and it is confirmed that the silicate composition of FIG. 3a and FIG. 3b can emit Eu ion after being doped with Eu ion³⁺A characteristic peak expressed as red orange light from 570nm to 750nm, and Eu²⁺The characteristic peak of blue-green light is shown in the range of 360nm to 550 nm; on the other hand, the composition of the silicate doped with Eu ions in the embodiment of the present invention can be excited by an excitation wavelength centered at 252nm within a range from 225nm to 320nm and an excitation wavelength centered at 365nm within a range from 320nm to 425nm, and further emit blue-green light or red-orange light.

Referring to FIG. 3d, FIG. 3d schematically shows a composition Ca of silicate-doped Eu ions according to an embodiment of the present invention_2.75Sr_1.25Si₂O₇F₂：1％Eu³⁺Fluorescence property at a detection wavelength of 621 nm. As can be seen from FIG. 3d, when the detection wavelength is 621nm, an excitation peak from 200nm to 350nm is obtained, the center of the excitation peak is 282nm, which indicates that the composition in this example can be excited at a wavelength from 200nm to 350nm to obtain red light at 621nm, and further, when the excitation wavelength is 282nm, the brightness of the red light at 621nm is the highest.

Referring to FIG. 3e, FIG. 3e schematically shows a fluorescence property of a silicate composition according to an embodiment of the invention at excitation wavelengths of 350nm, 365nm, 380nm and 400nm, respectively. As can be seen from fig. 3e, when the excitation wavelengths are 350nm, 365nm, 380nm and 400nm, the emission peaks with the emission wavelength ranges of 400nm to 575nm and 575nm to 725nm can be obtained, wherein the emission peak with the emission wavelength range of 400nm to 575nm shows blue-green light, the emission peak with the emission wavelength range of 575nm to 725nm shows red-orange light, and when the excitation wavelength changes, the fluorescence intensity showing blue-green light in the range of 400nm to 575nm and the fluorescence intensity showing red-orange light in the range of 575nm to 725nm both change, and the blue-green light and the red-orange light emitted by the silicate composition after being excited in this embodiment are superimposed to obtain the final light color. It can be known from the common knowledge that the three primary colors of the television set are red, green and blue, respectively, and therefore, when the excitation wavelength in this embodiment is changed, the silicate composition in which both the blue-green light component and the red-orange light component can be changed is obtained, so that the final color expressed by the silicate composition in this embodiment can be converted from blue light-purple light-white light-red-orange light, and further can be applied to the fields of LED display panels, automobile tail lights and anti-counterfeiting identification.

The invention also provides a preparation method of silicate material doped with other rare earth ions, referring to fig. 4, fig. 4 schematically shows a flow chart of a preparation method of the silicate composition in the embodiment of the invention, and the preparation method comprises the following steps:

s1, weighing CaCO₃、SrCO₃Or BaCO₃In (1)At least one of weighing CaCl₂、CaF₂、CaBr₂At least one of them, weighing Eu₂O₃、CeO₂、Sm₂O₃And weighing SiO₂And grinding after uniform mixing to obtain mixed powder.

Example 1

To synthesize Ca_2.75Sr_1.25Si₂O₇F₂Eu-doped²⁺And Eu³⁺For example, the silicate is doped with Eu²⁺And Eu³⁺The chemical formula (c) is as follows: ca_2.75Sr_1.25Si₂O₇F₂：Eu^2+/3+And is denoted as the first sample. Synthesis of 0.126mol Ca_2.75Sr_1.25Si₂O₇F₂：Eu^2+/3+First sample Ca synthesized in detail_2.75Sr_1.25Si₂O₇F₂：Eu^2+/3+The amount of the substance(s) is not particularly limited in the present invention. According to Ca_2.75Sr_1.25Si₂O₇F₂：Eu^2+/3+Weighing raw materials according to the ratio of the substance amount of each substance in the chemical formula. Weighing CaCO₃0.3469g, weighing SrCO₃、CaF₂、SiO₂And Eu₂O₃The masses of (A) were 0.1476g, 0.1546g, 0.2379g and 0.0035g, respectively. The raw materials were ground in an agate mortar for 20 minutes so that the raw material powders could be mixed uniformly, which was recorded as mixed powder one, and then the mixed powder one was transferred to an alumina crucible.

And S2, placing the mixed powder in a high-temperature furnace, introducing gas into the high-temperature furnace, calcining at a first temperature within a first preset time, cooling, and grinding to obtain a precursor.

In the embodiment of the present invention, the first mixed powder is placed in an alumina crucible and then placed in a high temperature furnace, and air is introduced into the high temperature furnace, wherein the calcination temperature in this embodiment may be, for example, 900 ℃, and the calcination time may be, for example, 120 minutes, to obtain a first precursor, and the specific calcination temperature and calcination time are not specifically limited in the present invention; the process of raising the temperature of the high-temperature furnace from room temperature to 900 ℃ comprises the following steps: the temperature in the furnace is increased from room temperature to 900 ℃ by setting the high temperature furnace at a rate of 10 ℃ per minute, which provides the advantage of making the particle size of the synthesized composition more uniform.

And S3, placing the precursor into a high-temperature furnace, introducing gas into the high-temperature furnace, and calcining the precursor at a second temperature within a second preset time range to obtain the silicate composition.

Placing the first grinded precursor obtained in step S2 in a high temperature furnace, and introducing air into the high temperature furnace, wherein the second preset time may be, for example, 1200 ℃, and the calcination time may be, for example, 240 minutes in the embodiment of the present invention, to obtain the silicate composition, and the specific calcination temperature and calcination time are not limited in the present invention. The process of raising the temperature of the high-temperature furnace from room temperature to 1200 ℃ comprises the following steps: the temperature is increased to 1000 ℃ at a rate of 10 ℃ per minute and then to 1200 ℃ at a rate of 5 ℃ per minute, which temperature increase enables to obtain Ca with better crystallinity_2.75Sr_1.25Si₂O₇F₂：Eu^2+/3+A silicate composition.

Example 2

To synthesize Ca_2.75Sr_1.25Si₂O₇F₂Doping with Ce³⁺And Eu³⁺For example, the silicate is doped with Ce³⁺And Eu³⁺The chemical formula (c) is as follows: ca_2.75Sr_1.25Si₂O₇F₂:Ce³⁺/Eu³⁺And noted as the second sample. Synthesis of 0.126mol Ca_2.75Sr_1.25Si₂O₇F₂:Ce³⁺/Eu³⁺Second sample Ca synthesized in detail_2.75Sr_1.25Si₂O₇F₂:Ce³⁺/Eu³⁺The amount of the substance(s) is not particularly limited in the present invention, and is in accordance with Ca_2.75Sr_1.25Si₂O₇F₂:Ce³⁺/Eu³⁺Weighing CaCO according to the ratio of the amount of each substance in the chemical formula₃、SrCO₃、CaF₂、SiO₂、Eu₂O₃And CeO₂The masses of (A) were 0.3469g, 0.1476g, 0.1546g, 0.2379g, 0.0035g and 0.0034g, respectively. And grinding the raw materials in an agate mortar for 20 minutes to uniformly mix the raw material powders to obtain a mixed powder II, and transferring the mixed powder II to an alumina crucible.

Introducing air into the high-temperature furnace, placing the mixed powder II in the high-temperature furnace, and calcining for 120 minutes at the temperature of 900 ℃, wherein the specific calcining temperature and calcining time are not specifically limited; in this example, the process of raising the temperature of the high temperature furnace from room temperature to 900 ℃ consisted of: and setting the high-temperature furnace to raise the temperature in the furnace from room temperature to 900 ℃ at a speed of raising the temperature by 10 ℃ per minute to obtain a second precursor.

A reducing gas, which may be, for example, 5 vol% H, is introduced into the high-temperature furnace₂And 95% by volume of O₂The composition of the mixed gas of (1) and the reducing gas is not specifically limited, and then the ground precursor is transferred to an alumina crucible and then placed in a high temperature furnace, the temperature of the high temperature furnace is increased by 10 ℃ per minute from room temperature to 1200 ℃, and then the high temperature furnace is calcined for 240 minutes at the temperature of 1200 ℃, so that a second sample Ca is obtained_2.75Sr_1.25Si₂O₇F₂:Ce³⁺/Eu³⁺。

Example 3

To synthesize Ca_2.75Sr_1.25Si₂O₇F₂：Eu^2+/3+For example, it is denoted as the third sample. Synthesis of 0.126mol Ca_2.75Sr_1.25Si₂O₇F₂:Eu^2+/3+Third sample Ca synthesized in detail_2.75Sr_1.25Si₂O₇F₂：Eu^2+/3+The amount of the substance(s) is not particularly limited in the present invention, and is in accordance with Ca_2.75Sr_1.25Si₂O₇F₂：Eu^2+/3+Weighing CaCO according to the ratio of the amount of each substance in the chemical formula₃、SrCO₃、CaF₂、SiO₂、Eu₂O₃The mass of (a) was 0.3469g, 0.1476g, 0.1546g, 0.2379g, and 0.0035g, respectively. C₂H₅NO₂,HNO₃The mass of (A) was 0.1523g and 0.2312g, respectively. And grinding the raw materials in an agate mortar for 20 minutes to uniformly mix the raw material powders to obtain a mixed powder III, and then transferring the mixed powder III into an alumina crucible.

Placing the mixed powder III in a high-temperature furnace, and calcining for 480 minutes at 1200 ℃, wherein the specific calcining temperature and calcining time are not specifically limited; in this example, the process of raising the temperature of the high temperature furnace from room temperature to 1200 ℃ consisted of: the high temperature furnace was set to raise the temperature in the furnace from room temperature to 900 c at a rate of 10 c per minute. Then, the temperature is raised to 1200 ℃ at a temperature rise rate of 5 ℃/min after 900 ℃, and a third sample Ca is obtained_2.75Sr_1.25Si₂O₇F₂：Eu² ^+/3+。

Example 4

To synthesize Ca_2.75Sr_1.25Si₂O₇F₂:Ce³⁺/Eu²⁺For example, it is denoted as the fourth sample. Synthesis of 0.126mol Ca_2.75Sr_1.25Si₂O₇F₂:Ce³⁺/Eu²⁺Fourth sample Ca synthesized in detail_2.75Sr_1.25Si₂O₇F₂:Ce³⁺/Eu²⁺The amount of the substance(s) is not particularly limited in the present invention, and is in accordance with Ca_2.75Sr_1.25Si₂O₇F₂:Ce³⁺/Eu²⁺Weighing CaCO according to the ratio of the amount of each substance in the chemical formula₃、SrCO₃、CaF₂、SiO₂、Eu₂O₃And CeO₂The masses of (A) were 0.3469g, 0.1476g, 0.1546g, 0.2379g, 0.0035g and 0.0034g, respectively. C₂H₅NO₂,HNO₃The mass of (A) was 0.1530g and 0.2326g, respectively. Grinding the raw materials in an agate mortar for 20 minutes to uniformly mix the raw material powders to obtain a mixed powder IV, and transferring the mixed powder IV to a mortar bedIn an alumina crucible.

Calcining at 1350 ℃ for 600 minutes in a high temperature furnace, wherein the specific calcining temperature and calcining time are not limited in the invention; heating the high temperature furnace from room temperature to 1000 deg.C at a temperature of 10 deg.C/min, heating to 1350 deg.C at a rate of 5 deg.C/min, and calcining at 1350 deg.C for 600 min to obtain a fourth sample Ca_2.75Sr_1.25Si₂O₇F₂:Ce³⁺/Eu²⁺。

Example 5

To synthesize Ca_2.75Sr_1.25Si₂O₇F₂：Eu^2+/3+For example, it is denoted as the fifth sample. Synthesis of 0.126mol Ca_2.75Sr_1.25Si₂O₇F₂:Ce³⁺/Eu²⁺Fifth sample Ca synthesized in detail_2.75Sr_1.25Si₂O₇F₂:Ce³⁺/Eu²⁺The amount of the substance(s) is not particularly limited in the present invention, and is in accordance with Ca_2.75Sr_1.25Si₂O₇F₂:Ce³⁺/Eu²⁺Weighing CaCO according to the ratio of the amount of each substance in the chemical formula₃、SrCO₃、CaF₂、SiO₂、Eu₂O₃The mass of (a) was 0.3469g, 0.1476g, 0.1546g, 0.2379g, and 0.0035g, respectively. The mass of citric acid was weighed to 0.3106 g. And preparing the weighed citric acid into an aqueous solution, and uniformly mixing and stirring the samples to prepare the gel. The prepared gel is put into an oven for drying, the temperature of the oven can be set to be 120 ℃, and the temperature of the oven is not particularly required. The dried xerogel is transferred to a high temperature furnace for calcination.

Introducing reducing gas into a high-temperature furnace, placing the mixed powder V into the high-temperature furnace, and calcining for 240 minutes at the temperature of 900 ℃, wherein the specific calcining temperature and calcining time are not specifically limited; in this example, the process of raising the temperature of the high temperature furnace from room temperature to 900 ℃ consisted of: and arranging a high-temperature furnace to increase the temperature in the furnace from room temperature to 900 ℃ at a speed of increasing the temperature by 5 ℃ per minute to obtain a precursor five, taking out the precursor five, and grinding.

A reducing gas, which may be, for example, 10 vol% H, is introduced into the high-temperature furnace₂And 90% by volume of O₂Transferring the grinded precursor V to an alumina crucible, placing the alumina crucible in a high-temperature furnace, raising the temperature of the high-temperature furnace from room temperature to 1000 ℃ at a rate of 10 ℃ per minute, raising the temperature to 1350 ℃ at a rate of 5 ℃ per minute, and calcining the precursor V at the temperature of 1350 ℃ for 360 minutes to obtain a fifth sample Ca_2.75Sr_1.25Si₂O₇F₂:Eu^2+/3+。

Example 6

To synthesize Ca_2.75Sr_1.25Si₂O₇F₂：Bi³⁺For example, it is denoted as the sixth sample. According to Ca_2.75Sr_1.25Si₂O₇F₂:Bi³⁺Weighing CaCO according to the ratio of the amount of each substance in the chemical formula₃、SrCO₃、CaF₂、SiO₂、Bi₂O₃The masses of (a) were 0.3469g, 0.1476g, 0.1546g, 0.2379g and 0.0047g, respectively. The mass of citric acid was weighed to 0.2896 g. And preparing the weighed citric acid into an aqueous solution, and uniformly mixing and stirring the samples to prepare the gel. The prepared gel is put into an oven for drying, the temperature of the oven can be set to be 120 ℃, and the temperature of the oven is not particularly required. The dried xerogel is transferred to an alumina crucible.

Placing the mixed powder VI in a high-temperature furnace, introducing air, and calcining at the temperature of 900 ℃ for 240 minutes, wherein the specific calcining temperature and calcining time are not specifically limited; in this example, the process of raising the temperature of the high temperature furnace from room temperature to 900 ℃ consisted of: and arranging a high-temperature furnace to increase the temperature in the furnace from room temperature to 900 ℃ at a speed of increasing the temperature by 5 ℃ per minute to obtain a precursor six, taking out the precursor six, and grinding.

Reducing gas (10% H) was introduced into the high-temperature furnace₂+90％O₂) In this embodiment, the reducing gas may be, for example, 10 vol% of H₂And 90% (by volume)) O of (A) to (B)₂Transferring the grinded precursor VI to an alumina crucible, placing the alumina crucible in a high-temperature furnace, raising the temperature of the high-temperature furnace from room temperature to 1000 ℃ at a speed of raising the temperature by 5 ℃ per minute, raising the temperature to 1350 ℃ at a speed of raising the temperature by 2 ℃ per minute, and calcining the alumina crucible at the temperature of 1350 ℃ for 360 minutes to obtain a sixth sample Ca_2.75Sr_1.25Si₂O₇F₂:Bi³⁺。

In the embodiment of the invention, for example, the rare earth ion Eu can be doped by changing^2+/3+、Ce³⁺、Sm³⁺And the combination proportion of blue light, green light and red light is further changed relative to the molar concentration of silicate, so that the adjustment of the spectral color is realized.

In the present invention, sample Ca of example 1 was_2.75Sr_1.25Si₂O₇F₂：Eu^2+/3+The sample is pure and is subjected to X-ray diffraction experiments, diffraction peaks appear at 11.97 degrees, 16.80 degrees, 19.28 degrees, 24.16 degrees, 27.39 degrees, 29.09 degrees, 31.14 degrees, 39.10 degrees, 44.99 degrees, 48.26 degrees, 49.98 degrees and 52.82 degrees of 2 theta, and the first sample can emit bright red light under the excitation of ultraviolet wavelengths of 254nm and 365 nm.

In this example, sample Ca of example 2 was used_2.75Sr_1.25Si₂O₇F₂:Ce³⁺/Eu³⁺When the diffraction is carried out on X-ray, characteristic diffraction peaks appear at 11.97 degrees, 16.80 degrees, 19.28 degrees, 24.16 degrees, 27.39 degrees, 29.09 degrees, 31.14 degrees, 39.10 degrees, 44.99 degrees, 48.26 degrees, 49.98 degrees and 52.82 degrees of 2 theta, and when the diffraction is excited by using excitation wavelength of 254nm, a narrow-band emission peak with an emission peak at 621nm is obtained, and the emission peak is represented as red light; when 365nm excitation is used, a broad band emission peak of 400nm-550nm is obtained, which appears as bright blue light.

In this example, sample Ca of example 3 was used_2.75Sr_1.25Si₂O₇F₂:Eu^2+/3+Performing X-ray diffraction, wherein characteristic diffraction peaks appear at 2 theta of 11.97 deg., 16.80 deg., 19.28 deg., 24.16 deg., 27.39 deg., 29.09 deg., 31.14 deg., 39.10 deg., 44.99 deg., 48.26 deg., 49.98 deg., 52.82 deg., and excitation is carried out at a wavelength of 254nmObtaining bright red light; bright blue light was obtained using 365nm excitation.

In this example, the sample of example 4 was subjected to X-ray diffraction, and characteristic diffraction peaks were obtained at 2 θ of 11.97 °,16.80 °,19.28 °, 24.16 °,27.39 °,29.09 °,31.14 °,39.10 °, 44.99 °, 48.26 °,49.98 °, and 52.82 °, and the fourth sample emitted bright blue light at excitation wavelengths of 254nm and 365 nm.

In this example, the sample of example 5 was subjected to X-ray diffraction, and characteristic diffraction peaks were observed at 2 θ of 11.97 °,16.80 °,19.28 °, 24.16 °,27.39 °,29.09 °,31.14 °,39.10 °, 44.99 °, 48.26 °,49.98 °, and 52.82 °, and the fifth sample emitted a mixed light of blue light and red light at an excitation wavelength of 254nm, and the adjustment of emission spectrum color was achieved by changing the Eu ion concentration.

In this example, when the sample of example 6 was subjected to X-ray diffraction, characteristic diffraction peaks appeared at 11.97 °,16.80 °,19.28 °, 24.16 °,27.39 °,29.09 °,31.14 °,39.10 °, 44.99 °, 48.26 °,49.98 °, and 52.82 ° of 2 θ, and the sixth sample was excited in the near ultraviolet band to the blue light band and emitted bright blue light.

The invention also provides a light-emitting device, which comprises the following components: a light emitting diode in which a gallium nitride semiconductor is provided; the silicate composition is arranged on the gallium nitride semiconductor, wherein the excitation wavelength range of the silicate composition is 254nm-400nm, and the emission wavelength range of the silicate composition is 400nm-750 nm; the silicate composition has a luminous range of blue light, green light, purple light and red light.

In an embodiment of the invention, the silicate composition has an excitation wavelength range of 254nm to 400nm, and is capable of being excited by ultraviolet light to produce an emission spectrum in the range of 400nm to 750nm, the emission spectrum corresponding to a color in the range of blue light-green light-purple light-white light-red light. When the excitation wavelength is changed in the 254nm range, the emission spectrum is changed, resulting in a spectrum of different colors. The change of the spectrum color can be applied to the fields of LED display panels, automobile tail lamps and anti-counterfeiting identification.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims

1. A rare earth metal-doped alkaline earth metal silicate material is characterized in that: a mixture of any one or more in the rare earth metal-doped alkaline earth metal silicate, wherein:

The general chemical formula of the alkaline earth metal silicate is M _x R _4-x Si ₂ O ₇ Y ₂ , M is Ca, Sr or Ba, R is Ca, Sr or Ba, 1≤x≤4; Y is F , any one or any two of Cl or Br;

The rare earth metal Re is at least one of Eu ^3+/2+ , Ce or Sm;

In the rare earth metal-doped alkaline earth metal silicate, the molar ratio of the rare earth metal to the alkaline earth metal silicate is greater than 0 and less than 0.1.

2. The rare earth metal-doped alkaline earth metal silicate material according to claim 1, wherein:

The alkaline earth metal silicate is selected from Ca _1.25 Sr _2.75 Si ₂ O ₇ FCl, Ca ₂ Sr ₂ Si ₂ O ₇ FBr, Ca ₃ Sr ₁ Si ₂ O ₇ FCl, Ca ₃ Sr ₁ Si ₂ O ₇ FBr, Ca _1.5 Any one of Sr _2.5 Si ₂ O ₇ F _{2 ,} Sr ₄ Si ₂ O ₇ FCl or Sr ₄ Si ₂ O ₇ Br ₂ .

3. The rare earth metal doped alkaline earth metal silicate material according to claim 2, wherein:

The position composition of the characteristic peak of the X-ray diffraction peak of the rare earth metal doped alkaline earth metal silicate on 2θ is: 11.97°, 16.80°, 19.28°, 24.16°, 27.39°, 29.09°, 31.14°, 39.10° °, 44.99°, 48.26°, 49.98°, 52.82°;

The unit cell volume of the rare earth metal doped alkaline earth metal silicate is

The crystal system of the doped silicate is monoclinic; the space point group of the doped silicate is P121/C1.

4. The rare earth metal doped alkaline earth metal silicate material according to any one of claims 1 to 3, wherein:

The excitation wavelength range of the rare earth metal doped alkaline earth metal silicate material is 254nm-400nm;

The emission wavelength range of the rare earth metal-doped alkaline earth metal silicate material is 400nm-750nm, and the emission is blue light, green light, purple light, white light or red light.

5. A method for preparing a rare earth metal-doped alkaline earth metal silicate material according to any one of claims 1 to 4, characterized in that, comprising the following steps:

The rare earth metal doped alkaline earth metal silicate material is prepared by a high temperature solid phase synthesis method;

Alternatively, the rare earth metal-doped alkaline earth metal silicate material is prepared by a combustion method;

Alternatively, the rare earth metal-doped alkaline earth metal silicate material is prepared by a sol-gel method.

6. The preparation method of the rare earth metal-doped alkaline earth metal silicate material according to claim 5, wherein:

The high temperature solid phase synthesis method comprises the following steps:

S1. Weigh at least one of the first raw materials CaCO ₃ , SrCO ₃ or BaCO ₃ , weigh at least one of the second raw materials CaCl ₂ , CaF ₂ , CaBr ₂ , weigh the third raw materials Eu ₂ O ₃ , At least one of CeO ₂ and Sm ₂ O ₃ , and weighed SiO ₂ , mixed uniformly and ground to obtain a ground sample;

S2, the grinding sample obtained in step 1) is placed in a high-temperature furnace, calcined in an atmosphere of air or a reducing gas, cooled and ground after calcination to obtain a precursor;

S3. The precursor obtained in step 2) is placed in a high-temperature furnace, and calcined in an atmosphere of air or a reducing gas to obtain the rare earth metal-doped alkaline earth metal silicate material, wherein:

The molar ratio of the first raw material, SiO ₂ and the second raw material is 3.9-4.1:1.9-2.1:0.9-1.1;

The molar ratio of the total molar amount of rare earth metals to the molar amount of SiO ₂ in the third raw material is greater than 0 and less than 0.05;

The combustion method includes the following steps:

S1, weigh at least one of the first raw materials CaCO ₃ , SrCO ₃ or BaCO ₃ , weigh at least one of the second raw materials CaF ₂ , CaCl ₂ or CaBr ₂ , weigh the third raw materials Eu ₂ O ₃ , At least one of CeO ₂ or Sm ₂ O ₃ , and weigh SiO 2, C ₂ H ₅ NO ₂ and HNO ₃ ;

S2, each raw material weighed in step S1 is added to the water, heated to evaporate the water, and simultaneously obtain a colloidal material;

S3, heating the colloidal material obtained in step S2 until it spontaneously ignites, and continuing to heat until the combustion reaction ends, to obtain the rare earth metal-doped alkaline earth metal silicate material, wherein:

The molar ratio of the total molar amount of rare earth metals to the molar amount of SiO ₂ in the third raw material is greater than 0 and less than 0.05, the molar ratio of C ₂ H ₅ NO ₂ to the first raw material is 1:2.1-0.9:1.8, and the HNO ₃ The molar ratio to the total molar amount of rare earth metals in the third raw material is 0.9:0.96～1:1.2～0.9:0.95;

The sol-gel method comprises the following steps:

S1. Weigh at least one of the first raw materials CaNO ₃ , SrNO ₃ or BaNO ₃ , weigh at least one of the second raw materials CaF ₂ , CaCl ₂ or CaBr ₂ , weigh the third raw materials Eu ₂ O ₃ , At least one of CeO ₂ or Sm ₂ O ₃ , and weigh SiO ₂ ;

S2, the step S1 is weighed and fully mixed with the citric acid aqueous solution, heated and stirred until a gel is formed;

S3, drying the gel obtained in step S2 into a xerogel, and then calcining the xerogel at a high temperature to obtain the rare earth metal-doped alkaline earth metal silicate material, wherein:

The molar ratio of the total molar amount of rare earth metals to the molar amount of SiO ₂ in the third raw material is greater than 0 and less than 0.05.

7. The preparation method of the rare earth metal-doped alkaline earth metal silicate material according to claim 6, wherein:

In the high temperature solid phase synthesis method:

In step S2, the primary gas is a mixture of hydrogen and nitrogen, wherein the volume fraction of hydrogen is 5-10%; the calcination method is to increase to 1200-1600°C at a rate of 5°C-10°C per minute , the calcination time is 4-6h;

In step S3, the calcination method is to raise the temperature to 1200-1600°C at a rate of 2°C to 5°C per minute, the calcination time is 5 to 10h, and the calcination temperature in step S3 is higher than the calcination temperature in step S2;

In the combustion method:

In step S2, the dosage ratio of each raw material and the water in step 1) is 1:3～1:1.6g/ml, and the heating temperature is 95～100°C;

In step S3, the heating temperature after self-ignition is 1150-1250°C;

In the sol-gel method:

In step S2, the concentration of the citric acid aqueous solution is 0.5ml/mol～2.0ml/mol, the dosage ratio of each raw material and the citric acid aqueous solution in step 1) is 1:2.6～1:1.5g/ml, heating The temperature is 95 ~ 100 ℃;

In step S3, the drying temperature is 115-125°C, and the calcining temperature is 1200-1400°C.

8. An application of the rare earth metal-doped alkaline earth metal silicate material according to any one of claims 1 to 4, characterized in that it is used as a light-emitting material.

9 . The application of the rare earth metal doped alkaline earth metal silicate material according to claim 8 , characterized in that it is used as an anti-counterfeiting luminescent material. 10 .

10. A light-emitting device, comprising a light-emitting diode, wherein the light-emitting diode has a gallium nitride semiconductor, wherein a light-emitting layer is provided on the gallium nitride semiconductor, and the material of the light-emitting layer is selected from claims 1 to 4 Any of the rare earth metal doped alkaline earth metal silicate materials.