1. Luminescent material with a high color rendering index, characterized in that the luminescent material passes Eu³⁺Replacing part of sensitizing ions in the matrix to obtain the product; wherein the content of the first and second substances,

Eu³⁺to activate the ions;

sensitizing ion for making Eu³⁺Can be excited by electromagnetic wave with wavelength ranging from 340nm to 380 nm.

2. The luminescent material according to claim 1, wherein the chemical formula of the luminescent material is:

A_XB_YC_Z(DE_L)_M:QF^T+，A_XB_YC_Z(DE_L)_Mis used as a substrate and is provided with a plurality of layers,F^T+for replacing part of the C ions in the matrix, F^T+The proportion of the substituted C ions is Q; wherein the content of the first and second substances,

F^T+f is Eu for activating ions, the value range of Q is 0.01-0.99, and the value of T is 3;

c ions are sensitizing ions, and Z takes the value of 1-Q.

3. The luminescent material according to claim 2, wherein A is an alkaline earth metal, B is an alkaline earth metal or a transition metal, C is an alkaline earth metal or a rare earth element, DE_LIs PO₄。

4. The phosphor of claim 3, wherein DE is_LIs PO₄When the component A is Ca, B is Zn, C is Tb, X is 8, Y is 1, and M is 7.

5. A luminescent material as claimed in any one of claims 2 to 4, wherein Q is 0.2.

6. A method for preparing a luminescent material according to claim 4, wherein a high temperature solid phase synthesis method is used, comprising:

weighing corresponding raw materials according to the chemical formula of the luminescent material;

fully grinding the weighed raw materials to uniformly mix the raw materials;

fully roasting the uniformly mixed raw materials, and then cooling the raw materials to room temperature along with the furnace to obtain a sinter;

and grinding the sinter cooled to room temperature into powder to obtain the luminescent material.

7. The method for preparing a luminescent material according to claim 6, wherein a dispersing agent such as absolute ethyl alcohol is added in the process of fully grinding the weighed raw materials to uniformly mix the raw materials;

the process of fully grinding the weighed raw materials to uniformly mix the raw materials is carried out in an agate mortar;

the process of fully roasting the uniformly mixed raw materials is carried out in a non-reducing atmosphere;

the sintering temperature of the fully roasting process of the uniformly mixed raw materials is 1300-1500 ℃, and the sintering time is 2-10 h.

8. The method for producing a luminescent material according to claim 6 or 7, wherein the raw materials include:

at least one of an alkaline earth metal oxide, an alkaline earth metal carbonate, an alkaline earth metal nitrate, a transition metal oxide, a transition metal carbonate, and a transition metal nitrate;

at least one of rare earth oxide, rare earth carbonate, and rare earth nitrate;

and at least one of monoammonium phosphate and diammonium phosphate; wherein the content of the first and second substances,

the rare earth elements in the rare earth oxides, carbonates and nitrates include at least Eu.

9. The method according to claim 8, wherein the raw materials include calcium carbonate, europium oxide, zinc oxide, terbium oxide, and ammonium dihydrogen phosphate.

10. A white LED comprising a near-uv light source and a luminescent material according to any one of claims 1 to 5 and/or a luminescent material produced by the method of any one of claims 6 to 9.

Background

Light Emitting Diodes (LEDs) are called fourth-generation illumination sources because they have the advantages of high efficiency, energy saving, long service life, and the like, compared with conventional fluorescent lamps, and are currently widely used in the fields of indication, illumination, and display.

Among LEDs with different light emission colors, white LEDs are more widely used because their light emission efficiency is much higher than that of other LEDs. At present, white light LEDs are mainly realized by exciting yellow phosphor by blue light chips to obtain white light, for example, by exciting yellow phosphor Y by InGaN blue light chips₃Al₅O₁₂:Ce³⁺(abbreviated as YAG: Ce)³⁺Where YAG is yttrium aluminum garnet and Ce is cerium) to obtain white light. However, the white light LED obtained by the above method has the problems of low color rendering index (lower than 80) and high color temperature (higher than 6500K), so that the application field of the white light LED is limited.

Disclosure of Invention

The inventor finds that when the problems of low color rendering index and high color temperature of the white light LED on the market are solved: the reason why the color rendering index of the white light LED on the market is low and the color temperature is high is mainly because the spectrum of the white light LED obtained by the technology of exciting the yellow fluorescent powder by using the blue light chip lacks the red light component. The inventors thus conceived of doping a host with a rare earth ion Eu, which emits mainly red light when electrons are excited to undergo an energy level transition³⁺(also called trivalent europium ion) to improve the red light component, Eu, in white light LED³⁺The light source of (2) is in transition of electrons in the inner layer 4f, and the emission is mainly from electron channels⁵D₀To⁷F_J(J-1, 2, 3, 4) transition of energy level, e.g. when Eu³⁺Occupying inverted center of symmetry lattice in latticeWhen in place, the⁵D₀—⁷F₁Emission is dominant, showing orange-red light emission; when Eu is used³⁺When occupying the non-inversion symmetric center lattice position, the space-balance selection rule is broken, and at this time, the space-balance selection rule is broken⁵D₀—⁷F₂Mainly emitted, exhibits red light emission, resulting in Eu³⁺The doping in different hosts results in different intensities and colors of luminescence. However, since Eu³⁺Has a small absorption cross section, is not easy to be effectively excited, and is difficult to find suitable Eu³⁺To obtain a luminescent material capable of stably emitting an emission light having a red component, and since Eu³⁺The characteristic excitation wavelength of the chip is 393nm, and the chip cannot be effectively excited by the existing near ultraviolet chip. For this reason, the inventors have conducted extensive studies and experiments and have occasionally found that Eu is used as Eu³⁺For activating ions and including Eu in the matrix³⁺Sensitizing ions capable of being excited by electromagnetic wave with wavelength ranging from 340nm to 380nm, by Eu³⁺And replacing part of sensitizing ions in the matrix to obtain the luminescent material. Therefore, the luminescent material can be excited to Eu by sensitizing ions under the excitation of a near ultraviolet chip with the luminescent wavelength close to 370nm³⁺Transmit energy so that Eu³⁺Can be excited by electromagnetic wave with wavelength close to 370nm, Eu³⁺After being excited, the main emission waveband ranges from 590nm to 710nm, the red light component is provided, and the strongest emission peak is positioned at 616nm, so that bright red light can be emitted. Meanwhile, due to the existence of the chip capable of emitting near ultraviolet with the wavelength of 370nm, the prepared luminescent material can be combined with the existing near ultraviolet chip to obtain a luminescent device, so that the luminescent material can be applied.

In some embodiments, the luminescent material has the general chemical formula: a. the_XB_YC_Z(DE_L)_M:QF^T+，A_XB_YC(DE_L)_MAs a base, F^T+For replacing part of the C ion in the matrix, F^T+Substituted for C ionsThe ratio is Q; wherein, F^T+F is Eu for activating ions, the value range of Q is 0.01-0.99, and the value of T is 3; c ions are sensitizing ions, and Z takes the value of 1-Q. Based on the selected active ion, when selecting the sensitizing ion, it is necessary to select an ion which has similar radius and valence with the active ion under the same coordination condition, and has an emission spectrum which is spectrally overlapped with the excitation spectrum of the active ion, for example, Tb³⁺. Through the sensitization of the sensitizing ions, Eu can be obtained under the excitation of the wavelength close to 370nm³⁺The light emission of (1). Due to Tb³⁺Is at 370nm, and there is a near-ultraviolet chip of 370nm, whereby the optimum performance of the luminescent material can be exhibited when the luminescent material is excited by the near-ultraviolet chip of 370nm, and therefore Tb is preferred³⁺As sensitizing ions for the luminescent material; moreover, due to Tb³⁺The strongest emission peak after being excited is positioned at 543nm, can emit bright green light, and can simultaneously and jointly emit light under the excitation of the wavelength close to 370nm, the emission waveband range of the obtained luminescent material is 480nm-710nm, and the emitted light contains green light components and red light components, and can be adjusted by adjusting Eu³⁺Substituted Tb³⁺The proportion of green light and red light emitted by the luminescent material after being excited is adjusted, and the specific implementation is as follows: when Eu is used³⁺Substituted Tb³⁺The amount of (less than original Tb in the matrix) is small³⁺15% of the total), the light emitted by the luminescent material after excitation is green; when Eu is used³⁺Substituted Tb³⁺The amount of the active component accounts for the original Tb in the matrix³⁺15-20% of the total amount, the light emitted by the luminescent material after being excited is yellow; when Eu is used³⁺Substituted Tb³⁺The amount of the active component (larger than the original Tb in the matrix)³⁺20% of the total), the light emitted by the luminescent material after excitation deviates red. And the active ion adopts Eu³⁺，Eu³⁺Partial Tb in alternative matrices³⁺The sensitizing ion adopts Tb³⁺By adjusting the substitution ratio, the luminescent color of the luminescent material is adjusted, since Eu³⁺The luminescent color of the material is red, so that the obtained luminescent material has wider color adjustable range.

In the preferred embodimentIn example F^T+The proportion of the substitutional C ions is 0.01 so that the light emitting material emits light of the highest intensity under excitation at an excitation wavelength of 370 nm.

In some embodiments, A may be an alkaline earth metal, B may be an alkaline earth metal or a transition metal, C may be an alkaline earth metal or a rare earth element, DE_LIs PO₄。

In a preferred embodiment, when DE_LIs PO₄When A is Ca, B is Zn, C is Tb, X is 8, Y is 1, and M is 7. Thus, when Eu is used³⁺Alternative matrix Ca₈ZnTb_1-Q(PO₄)₇Middle part Tb³⁺Then, Eu³⁺Occupying the non-inverted symmetrical center sites in the lattice, a transition of greater intensity can be produced, in this case⁵D₀—⁷F₂Emission is dominant, and red light emission with higher intensity is shown, so that a luminescent material with higher luminous intensity can be obtained.

In some embodiments, when the light of the luminescent material to be obtained is yellow, the value of Q is 0.2, so as to obtain yellow light with better effect.

According to an aspect of the present invention, there is also provided a method for preparing the above luminescent material with high color rendering index, which employs a high temperature solid phase synthesis method, comprising:

according to the formula A of the luminescent material with high color rendering index_XB_YC_Z(DE_L)_M:QF^T+Weighing corresponding raw materials;

fully grinding the weighed raw materials to uniformly mix the raw materials;

fully roasting the uniformly mixed raw materials, and then cooling the raw materials to room temperature along with the furnace to obtain a sinter;

and grinding the sinter cooled to room temperature into powder to obtain the luminescent material.

The preparation method of the luminescent material with high color rendering index is prepared by adopting a high-temperature solid-phase synthesis method, so that the process is simple, the operation is convenient and fast, and the conditions are easy to control; meanwhile, as the substrate and the active ions selected by the luminescent material do not generate harmful substances in the high-temperature solid-phase synthesis process, the operation is safe, and the environment is not harmed.

In some embodiments, the dispersing agent is added during the process of sufficiently grinding the weighed raw materials to uniformly mix them. Selection principle of the dispersant: the raw materials can be uniformly mixed and easily separated from the raw materials, and meanwhile, the raw materials can not react with the raw materials, and the dispersing agent is a safe and nontoxic material. Therefore, the process of grinding and uniformly mixing the raw materials can be accelerated; but also shorten the reaction time for obtaining the compound by roasting; meanwhile, segregation can be avoided due to the addition of the dispersing agent, so that the crystal quality of the compound obtained by roasting can be improved.

In some embodiments, the weighed raw materials are ground sufficiently to mix them uniformly in an agate mortar. Because the agate mortar has the performances of pressure resistance, acid and alkali resistance, high strength, high wear resistance and the like, the raw materials are put into the agate mortar for grinding, and impurities are not easily introduced in the grinding process.

In some embodiments, the process of fully calcining the uniformly mixed raw materials is performed in a non-reducing atmosphere. For example, air or an inert gas may be used as the non-reducing atmosphere, and it is preferable that the raw materials mixed uniformly are fully calcined in an air atmosphere from the viewpoint of economy of the production method. Thereby, the Eu in the raw material during the baking process can be avoided³⁺Is reduced to Eu²⁺Resulting in problems such as a low proportion of the resulting complex.

In some embodiments, the sintering temperature of the fully-mixed raw materials is 1300-1500 ℃ and the sintering time is 2-10 h. Therefore, the raw materials can be ensured to be fully reacted.

In some embodiments, the feedstock comprises: at least one of an alkaline earth metal oxide, an alkaline earth metal carbonate, and an alkaline earth metal nitrate; at least one of transition metal oxide, transition metal carbonate and transition metal nitrate; at least one of rare earth oxide, rare earth carbonate, and rare earth nitrate; and at least one of monoammonium phosphate and diammonium phosphate; wherein the rare earth elements in the rare earth oxide, the rare earth carbonate and the rare earth nitrate at least comprise Eu. As some of the examples, the starting materials include calcium carbonate, europium oxide, zinc oxide, terbium oxide, and ammonium dihydrogen phosphate.

According to one aspect of the invention, a white light LED is provided, which comprises a near ultraviolet light source and a front luminescent material and/or a luminescent material prepared by the preparation method.

Drawings

FIG. 1 shows Ca₈ZnTb(PO₄)₇、Ca₈ZnTb_0.9(PO₄)₇：0.1Eu³⁺、Ca₈ZnTb_0.5(PO₄)₇：0.5Eu³⁺And Ca₈ZnTb_0.2(PO₄)₇：0.8Eu³⁺XRD pattern of (a);

FIG. 2 shows Ca₈ZnTb(PO₄)₇Excitation spectrogram while monitoring 543nm emission position;

FIG. 3 shows Ca₈ZnTb(PO₄)₇A fluorescence spectrum under the excitation of 370nm near ultraviolet light;

FIG. 4 shows Ca₈ZnTb_0.8(PO₄)₇：0.2Eu³⁺A fluorescence spectrum under the excitation of 370nm near ultraviolet light;

FIG. 5 shows Ca₈ZnTb_0.20(PO₄)₇：0.80Eu³⁺、Ca₈ZnTb_0.50(PO₄)₇：0.50Eu³⁺、Ca₈ZnTb_0.80(PO₄)₇：0.20Eu³⁺、Ca₈ZnTb_0.85(PO₄)₇：0.15Eu³⁺、Ca₈ZnTb_0.9(PO₄)₇：0.1Eu³⁺、Ca₈ZnTb_0.95(PO₄)₇：0.05Eu^{3 +}And Ca₈ZnTb_0.98(PO₄)₇：0.02Eu³⁺The fluorescence spectrum of the luminescent material under the excitation of 370nm near ultraviolet light;

FIG. 6 shows Ca₈ZnTb_0.8(PO₄)₇：0.2Eu³⁺Fluorescence spectra under 370nm near UV excitation at 300K, 350K, 400K, 450K and 500K.

Detailed Description

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict.

It is further noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element. The terms used herein are generally terms commonly used by those skilled in the art, and if they are inconsistent with such commonly used terms, the terms herein control.

As used herein, the term "host" refers to the major components of a luminescent material that are greater than about 90% by weight of the luminescent material and that all have beta-Ca₃(PO₄)₂The structure can form solid solution in a wide composition range, is beneficial to doping of ions in various valence states, and can adjust the position of emission wavelength by changing the composition of a substrate and activating the concentration of ions, so that the luminescent material presents different luminescent colors.

In this context, the term "active ion" refers to an ion in the luminescent material that is doped into the host, and is capable of activating the host when subjected to external excitation and forming a luminescent center.

In this context, the term "sensitizing ion" refers to an ion in the luminescent material that is doped into the host and that can absorb excitation radiation and transfer energy to the activating ion, the doping of the sensitizing ion in the luminescent material can increase the luminescent efficiency of the luminescent material.

As used herein, the term "high temperature solid phase synthesis" refers to a process for producing a large batch of complex oxides by contacting, reacting, nucleating, and crystal growth reactions between solid interfaces at high temperatures (1000 ℃ to 1500 ℃).

As used herein, the term "dispersant" refers to a substance capable of reducing the aggregation of solid ions in a dispersion.

As used herein, the term "calcination" refers to the process of completing a chemical reaction below the melting temperature of the material.

In this context, the term "furnace cooling" refers to a process in which after the material is roasted in the roasting furnace, heating is stopped, and the roasted material discharges heat from the object to the environment medium in the roasting furnace through heat transfer modes such as heat exchange, convection, heat radiation and the like, so as to reduce the temperature of the object and finally achieve the same spontaneity as the environment temperature.

In the present document, the term "color rendering index" refers to a parameter for characterizing the color rendering capability of a light source to an object, and the value range thereof is 20 to 100. The higher the value of the color rendering index of the light source, the better the color rendering capability thereof.

In this context, the term "color temperature" refers to a physical quantity in illumination optics that is used to define the color of a light source. That is, a black body is heated to a temperature at which the color of light emitted from the black body is the same as the color of light emitted from a light source, and the temperature heated by the black body is called the color temperature of the light source, which is called color temperature for short. The units are expressed in "K" (Kelvin temperature units).

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The luminescent material having a high color rendering index according to one embodiment of the present invention passes Eu³⁺Replacing part of sensitizing ions in the matrix to obtain the product; wherein, Eu³⁺To activate the ions; sensitizing ion for making Eu³⁺Can be excited by electromagnetic wave with wavelength ranging from 340nm to 380 nm. Based on the selected active ion, when selecting the sensitizing ion, the ion which has similar radius and valence with the active ion under the same coordination condition and has the spectrum overlapping with the excitation spectrum of the active ion needs to be selected, wherein Tb³⁺Since the most intense excitation site thereof is 370nm, it is preferable as a sensitizing ion in the host of the luminescent material so that the luminescent intensity of the resulting luminescent material is higher. Moreover, due to Tb³⁺The strongest emission peak after being excited is positioned at 543nm, can emit bright green light, and can be adjusted by regulating Eu³⁺Substituted Tb³⁺The ratio of green light and red light emitted by the luminescent material after excitation is adjusted. In some preferred embodiments, Eu is used to obtain a phosphor with higher luminous intensity³⁺The proportion of the sensitizing ions in the substituted matrix is 0.01, so that the luminescent material can emit light with higher intensity under the excitation of a near ultraviolet chip with the luminescent wavelength close to 370 nm. In other preferred embodiments, Eu is used if the phosphor is selected to provide a yellow emission with a better yellow emission³⁺The proportion of sensitizing ions in the surrogate matrix was 0.2.

As one of the embodiments of the light emitting material, the chemical formula of the light emitting material is set to A_XB_YC_Z(DE_L)_M:QF^T+(ii) a Wherein A is_XB_YC_Z(DE_L)_MAs a base, F^T+For replacing part of the C ion in the matrix, F^T+The proportion of the substituted C ions is Q; wherein, F^T+F is Eu for activating ions, the value range of Q is 0.01-0.99, and the value of T is 3; c ions are sensitizing ions, and Z takes the value of 1-Q. Illustratively, the composition of the matrix may be as follows: a is selected from alkaline earth metals, e.g. beryllium Be, magnesium Mg, calcium Ca, strontium Sr, barium Ba and radium RaAt least one of (a); b is selected from alkaline earth metal or transition metal, and the transition metal is at least one of titanium Ti, vanadium V, chromium Cr, manganese Mn or zinc Zn; c is selected from an alkaline earth metal or a rare earth element, for example using at least one of scandium Sc, yttrium Y or a lanthanide (i.e. using at least one of scandium Sc, yttrium Y, lanthanum La, praseodymium Pr, neodymium Nd, cerium Ce, samarium Sm, europium Eu, gadolinium Gd, terbium Tb, dysprosium Dy, holmium Ho, erbium Er, thulium Tm, ytterbium Yb and lutetium Lu); DE_LIs PO₄。

In some embodiments, in the matrix of the present invention, a is calcium Ca, B is zinc Zn, C is terbium Tb, X is 8, Y is 1, M is 7, and the obtained matrix has a chemical formula of: ca₈ZnTb(PO₄)₇. By doping Eu in matrix³⁺，Eu³⁺By substituting Tb in the substrate³⁺Is doped in a matrix to obtain a chemical formula of Ca₈ZnTb_1-Q(PO₄)₇：QEu³⁺(Q is more than or equal to 0.01 and less than or equal to 0.99, Q is Eu³⁺Substituted Tb³⁺Molar amount of) a luminescent material. By detecting the matrix Ca₈ZnTb(PO₄)₇The maximum excitation wavelength lambda of the matrix can be obtained from the excitation spectrum_ex370nm (as shown in FIG. 2); the maximum emission wavelength lambda of the matrix can be obtained when the matrix is excited at the maximum excitation wavelength_em(see FIG. 3), it can be seen from FIG. 3 that the selected matrix Ca₈ZnTb(PO₄)₇The LED can emit light with the wavelength of 480nm-710nm under the irradiation of a light source with the wavelength of 370nm, wherein, green light is mainly emitted, and simultaneously, a small amount of blue light, yellow light and orange light are accompanied, and red light components are lacked. The invention is characterized in that Eu is doped in the matrix³⁺Substituted for part of Tb³⁺To obtain a luminescent material capable of emitting red light upon excitation at the maximum excitation wavelength, Eu in an amount of 0.2 molar by doping in the host as illustrated from FIG. 4³⁺The obtained chemical formula is Ca₈ZnTb_0.8(PO₄)₇：0.2Eu³⁺The fluorescence spectrum of the luminescent material (2) shows that the substituted part Tb is doped in the matrix³⁺Eu (E)³⁺The obtained luminescent material emits light in the wavelength range after being excited480nm-710nm, which is wider than the light-emitting range of the substrate, and the intensity of green light of the emitted light is weakened, and simultaneously, a red light component appears; moreover, since when Eu is used³⁺Alternative matrix Ca₈ZnTb_1-Q(PO₄)₇Middle part Tb³⁺Then, Eu³⁺Occupying the non-inverted symmetrical center sites in the lattice, a transition of greater intensity can be produced, in this case⁵D₀—⁷F₂Emission is dominant, and red light emission with higher intensity is shown, so that a luminescent material with higher luminous intensity can be obtained. Meanwhile, referring to FIG. 5, it can be seen that when Eu is used³⁺Substitute for Tb³⁺When the proportion of (A) is below 0.15, the green light component of the light emitted by the luminescent material after being excited accounts for most of the light, and the red light component accounts for a few of the light, namely the luminescent material mainly emits green light; when Eu is used³⁺Substitute for Tb³⁺When the proportion of the red light emitting material is in the range of 0.15-0.2, the green light component in the light emitted by the luminescent material after being excited is equivalent to the red light component, namely the luminescent material mainly emits yellow light; when Eu is used³⁺Substitute for Tb³⁺When the ratio of (A) is in the range of 0.2 or more, the red component and the green component of the light emitted from the light-emitting material after excitation are predominant and the light-emitting material is mainly red, whereby Eu can be increased by adjusting³⁺Replacement of Tb in matrix³⁺The molar weight of the organic electroluminescent material is used for realizing the adjustment of the color of the light emitted by the obtained luminescent material after being excited from green to yellow to red; further, the light emitting position of the light emitting material is not changed by the temperature change (see fig. 6).

Matrix Ca measured according to FIG. 2₈ZnTb(PO₄)₇Based on the fact that the luminescent material prepared by the substrate has the maximum luminous intensity at the wavelength of 370nm of the light source, the white light LED of one embodiment of the invention adopts near ultraviolet light as the light source on the basis of the luminescent material with high color rendering index, so as to obtain the white light LED with the highest luminous intensity.

As an embodiment of the aforementioned method for preparing a luminescent material having a high color rendering index, it employsBy high temperature solid phase synthesis comprising: according to the formula A of the luminescent material with high color rendering index_XB_YC_Z(DE_L)_M:QF^T+Weighing corresponding raw materials; fully grinding the weighed raw materials to uniformly mix the raw materials; fully roasting the uniformly mixed raw materials, and then cooling the raw materials to room temperature along with the furnace to obtain a sinter; and grinding the sinter cooled to room temperature into powder to obtain the luminescent material. The luminescent material with high color rendering index is prepared by adopting a high-temperature solid-phase synthesis method, so that the process is simple, the operation is convenient and fast, and the conditions are easy to control; meanwhile, as the substrate and the active ions selected by the luminescent material do not generate harmful substances in the high-temperature solid-phase synthesis process, the operation is safe, and the environment is not harmed.

Exemplary, the starting materials include: alkaline earth metal oxides (e.g. calcium oxide, CaO), alkaline earth metal carbonates (e.g. calcium carbonate, CaCO)₃Magnesium carbonate MgCO₃Or barium carbonate BaCO₃Etc.) and alkaline earth metal nitrates (e.g., calcium nitrate, Ca (NO)₃)₂) At least one of; transition metal oxides (e.g. zinc oxide ZnO or manganese oxide MnO), transition metal carbonates (e.g. zinc carbonate ZnCO)₃) And transition metal nitrates (e.g., zinc nitrate Zn (NO))₃)₂·6H₂At least one of O); rare earth oxides (e.g. europium oxide Eu)₂O₃Or terbium oxide Tb₄O₇) Rare earth carbonates (e.g. europium carbonate Eu)₂(CO₃)₃Or terbium carbonate Tb₂(CO₃)₃) And rare earth nitrates (e.g. europium nitrate Eu (NO)₃)₃·6H₂O or terbium nitrate Tb (NO)₃)₃) At least one of; and ammonium dihydrogen phosphate NH₄H₂PO₄And diammonium hydrogen phosphate (NH)₄)₂HPO₄At least one of; wherein the rare earth elements in the rare earth oxide, the rare earth carbonate and the rare earth nitrate at least comprise Eu. As one of preferred examples, the raw materials include calcium carbonate, europium oxide, zinc oxide, terbium oxide, and ammonium dihydrogen phosphate.

In a preferred embodiment, the dispersing agent is added during the milling process. For example, the dispersant may be absolute ethanol. Therefore, the process of grinding and uniformly mixing the raw materials can be accelerated, the reaction time for obtaining the compound through roasting is shortened, the occurrence of segregation can be avoided, and the crystal quality of the compound obtained through roasting is improved; in addition, the absolute ethyl alcohol can be separated from the composite in the subsequent roasting process, so as to avoid introducing impurities into the composite obtained by roasting. In order to avoid the influence of the dispersant added in the grinding process on the roasting efficiency, the dispersant is separated from the uniformly mixed raw materials after the raw materials are ground and uniformly mixed and before the raw materials are roasted. Specifically, when the dispersing agent adopts absolute ethyl alcohol, after the raw materials are ground and uniformly mixed, the raw materials which are ground and uniformly mixed are dried before the raw materials are roasted, for example, the drying can be carried out in an oven, generally, in order to separate the absolute ethyl alcohol from the raw materials which are ground and uniformly mixed, the performance of the raw materials which are ground and uniformly mixed cannot be influenced, and the drying temperature of the oven is set to 70 +/-5 ℃ until the absolute ethyl alcohol is separated from the raw materials which are ground and uniformly mixed.

In some preferred embodiments, the feedstock is ground using an agate mortar. Because the agate mortar has high strength and is not easy to generate chemical reaction with the raw materials, impurities cannot be introduced into the raw materials in the grinding process. Similarly, the sintered product obtained after firing may be ground in an agate mortar to obtain a luminescent powder.

In a preferred embodiment, the firing process is conducted in a non-reducing atmosphere. To avoid Eu in the raw material during the roasting process³⁺Is reduced to Eu²⁺。

In some preferred embodiments, the sintering temperature of the roasting process is 1300-1500 ℃, and the sintering time is 2-10 h. To ensure the raw materials to fully react. Preferably, a corundum crucible is used to avoid reaction of the crucible with the raw material during firing. Preferably, the temperature rise rate in the roasting process is controlled to be 3 ℃/min-5 ℃/min, so that the corundum crucible is prevented from cracking under the condition that the temperature rise rate is as fast as possible.

The following description will be given to an exemplary method for preparing a luminescent material having a high color rendering index according to the present invention with reference to specific examples.

Example 1:

chemical formula A of luminescent material with high color rendering index_XB_YC_Z(DE_L)_M:QF^T+0.4003g of calcium carbonate, 0.0018g of europium oxide, 0.0407g of zinc oxide, 0.0916g of terbium oxide and 0.4026g of ammonium dihydrogen phosphate are weighed as raw materials respectively according to the molar ratio, and are transferred into an agate mortar for uniform mixing.

Grinding the raw materials for 5 minutes, adding a dispersing agent absolute ethyl alcohol, continuously and uniformly grinding for 5 minutes, and then putting the mixture into an oven to be dried at the drying temperature of 70 ℃ until the raw materials are dried.

And grinding the dried raw material powder, pouring the ground raw material powder into a corundum crucible, roasting the corundum crucible in air at the temperature rise rate of 5 ℃/min at 1400 ℃ for 6 hours, and naturally cooling to room temperature to obtain a sinter.

And uniformly grinding the sinter in an agate mortar to obtain the luminescent material with high color rendering index.

Examples 2 to 7 preparation of luminescent materials with high color rendering index

The parameters in table 1 to table 3 below are substituted for the parameters in example 1 accordingly, and a light emitting material having a high color rendering index is prepared as in example 1.

TABLE 1

TABLE 2

TABLE 3

Wherein, Ca in FIG. 1₈ZnTb_0.9(PO₄)₇：0.1Eu³⁺The XRD pattern of (a) is the XRD pattern of the luminescent material prepared in example 3; ca in FIG. 1₈ZnTb_0.5(PO₄)₇：0.5Eu³⁺The XRD pattern of (a) is the XRD pattern of the luminescent material prepared in example 6; ca in FIG. 1₈ZnTb_0.2(PO₄)₇：0.8Eu³⁺The XRD pattern of (a) is that of the luminescent material prepared in example 7.

In the embodiment of the invention, the oven can adopt an industrial blast oven with the model of HX-600F, and can also adopt other ovens in the prior art. The sintering furnace can adopt a box type sintering furnace with the model number of NBD-ML1200-10IC, and can also adopt other non-reduction type sintering furnaces in the prior art. The invention does not limit the specific types of the baking oven and the sintering oven.

What has been described above are merely some embodiments of the present invention. It will be apparent to those skilled in the art that various changes and modifications can be made without departing from the inventive concept thereof, and these changes and modifications can be made without departing from the spirit and scope of the invention.