CN117801819A - A high quantum efficiency rare earth silicate phosphor and its preparation method and application - Google Patents

Abstract

The invention relates to the technical field of rare earth fluorescent materials, in particular to high-quantum-efficiency rare earth silicate fluorescent powder, a preparation method and application thereof, wherein the chemical general formula of the rare earth silicate fluorescent powder is NaY _x Gd _y M _z Lu _{1‑x‑y‑z} SiO ₄ Wherein x is more than or equal to 0.02 and less than or equal to 1,0.02, y is more than or equal to 1,0.02 and z is more than or equal to 1; m is Tb or Eu. According to NaY _x Gd _y M _z Lu _{1‑x‑y‑z} SiO ₄ Raw materials corresponding to each element are weighed according to the stoichiometric ratio, mixed and ground, and then sintered at 800-1500 ℃ to obtain the high-efficiency rare earth silicate green light or red light fluorescent powder. According to the invention, through optimizing the element proportion, the interval between rare earth ion doping sites is increased, and the large-scale production of the rare earth silicate fluorescent powder with narrow luminous bandwidth and high quantum efficiency is realized.

Description

A kind of high quantum efficiency rare earth silicate phosphor and its preparation method and application

Technical Field

The invention relates to the technical field of rare earth fluorescent materials, and in particular to a high quantum efficiency rare earth silicate fluorescent powder and a preparation method and application thereof.

Background technique

In today's production and life, more than 30% of electrical energy is used for lighting. Compared with traditional light sources, white light solid-state lighting and display devices made of green and red phosphors combined with blue light diodes (LEDs) not only have higher electro-optical conversion efficiency and color rendering index, but also can save a lot of electricity. In the context of the country's vigorous promotion of the "dual carbon" goal, the large-scale application of solid-state lighting equipment will help reduce the power consumption of lighting.

One of the keys to further improving the performance of lighting and display devices and increasing luminous efficiency is to increase the quantum efficiency of phosphors. However, the patent for high-efficiency phosphors has been held by Japanese companies for a long time, which undoubtedly increases the cost of production and sales and hinders its further application. Not only that, traditional high-efficiency narrow-band luminescent phosphors, such as KSF: Mn ⁴⁺ (K ₂ SiF ₆ ), BAM: Eu ²⁺ (BaMgAl ₁₀ O ₁₇ ), CASN: Eu ²⁺ (CaAlSiN ₃ ), etc., need to be It is synthesized under high temperature and high pressure conditions, and some materials require inert gas protection during synthesis. In particular, the KSF fluoride phosphor, which is currently the most successfully commercialized, requires the use of high concentrations of highly toxic hydrofluoric acid for its synthesis, and the production process is not environmentally friendly.

Silicate-based phosphors have stable physical and chemical properties, mild synthesis conditions, and do not require high pressure or highly toxic raw materials, making them a good choice for preparing environmentally friendly phosphors. However, the quantum efficiency of silicate phosphors activated by rare earth ions is generally low. The main factor that determines their luminescence efficiency is the spacing of rare earth ion doping sites in the matrix material. When the spacing is too close, the excited state energy will be repeatedly transferred and quenched between the rare earth ions instead of emitting light in the form of radiative recombination. This process is also called concentration quenching. Therefore, the key to developing high-efficiency phosphors lies in redesigning the structure of the matrix material to further control the spacing of the rare earth ion doping sites.

In view of this, the present invention is proposed.

Contents of the invention

The purpose of the present invention is to provide a high quantum efficiency rare earth silicate phosphor and its preparation method and application. The matrix structure is redesigned based on the oxyapatite phase and the spacing between the rare earth ion doping sites is increased. Significantly improve quantum efficiency.

In order to achieve the above object, the present invention provides a high quantum efficiency rare earth silicate phosphor. The general chemical formula of the phosphor is NaY _x Gd _y M _z Lu _1-xyz SiO ₄ , where 0.02≤x<1, 0.02 ≤y<1, 0.02≤z<1; M is Tb or Eu. When M is Tb, it displays green light; when M is Eu, it displays red light.

The rare earth silicate phosphor significantly improves the quantum efficiency of the phosphor by regulating the type and content ratio of rare earth elements.

Preferably, 0.1≤x≤0.8, 0.1≤y≤0.6, 0.3≤z≤0.6, 1-x-y-z≤0.2.

More preferably, 0.2≤x≤0.6, 0.1≤y≤0.4, and x/y≥2, 0.3≤z≤0.5, 1-x-y-z≤0.1.

Further, the general chemical formula of the phosphor includes high quantum efficiency rare earth silicate green phosphor and high quantum efficiency rare earth silicate red phosphor. The green phosphor preferably includes NaY _0.4 Tb _0.5 Gd _0.1 SiO _4. NaY _0.3 Tb _0.5 Gd _0.2 SiO ₄ , NaY _0.2 Tb _0.5 Gd _0.3 SiO ₄ , NaY _0.1 Tb _0.5 Gd _0.4 SiO ₄ , NaY _0.4 Tb _0.4 Gd _0.2 SiO ₄ , NaY _0.5 Tb _0.4 Gd _0.1 SiO ₄ , NaY _0.3 Tb _0.4 Gd _0.3 SiO ₄ , NaY _0.4 Tb _0.3 Gd _0.3 SiO ₄ , NaY _0.6 Tb _0.3 Gd _0.1 SiO ₄ , NaY _0.5 Tb _0.3 Gd _0.2 SiO ₄ , NaY _0.3 Tb _0.5 Gd _0.1 Lu _0.1 SiO ₄ , one or more of kind; the red phosphor NaY _0.35 Tb _0.5 Gd _0.1 Lu _0.05 SiO ₄ , NaY _0.4 Eu _0.5 Gd _0.1 SiO ₄ , NaY _0.3 Eu _0.5 Gd _0.2 SiO ₄ , NaY _0.2 Eu _0.5 Gd _0.3 SiO ₄ , NaY _0.1 Eu _0.5 Gd _0.4 SiO ₄ , NaY _0.4 Eu _0.4 Gd _0.2 SiO ₄ , NaY _0.5 Eu _0.4 Gd _0.1 SiO ₄ , NaY _0.3 Eu _0.4 Gd _0.3 SiO ₄ , NaY _0.4 Eu _0.3 Gd _0.3 SiO ₄ , NaY _0.6 Eu _0.3 Gd _0.1 SiO ₄ . One or more of NaY _0.5 Eu _0.3 Gd _0.2 SiO ₄ , NaY _0.3 Eu _0.5 Gd _0.1 Lu _0.1 SiO ₄ , NaY _0.35 Eu _0.5 Gd _0.1 Lu _0.05 SiO ₄ .

Furthermore, the quantum efficiency of the high quantum efficiency rare earth silicate phosphor is ≥85%, preferably ≥90%.

The invention also provides a method for preparing the high quantum efficiency rare earth silicate phosphor powder described in any one of the above, including: weighing the corresponding elements according to the stoichiometric ratio of NaY _x Gd _y M _z Lu _1-xyz SiO ₄ The raw materials are mixed and ground, and then sintered at 800-1500°C to obtain high quantum efficiency rare earth silicate phosphor powder.

Furthermore, the sintering temperature is 1100-1300° C., and the sintering time is 1-6 hours.

Further, the raw material corresponding to the Na element is sodium salt, the raw material corresponding to the Y element is Y ₂ O ₃ , the raw material corresponding to the Gd element is Gd ₂ O ₃ , and the raw material corresponding to the M element is Tb ₄ O ₇ or Eu ₂ O ₃ , the raw material corresponding to the Lu element is Lu ₂ O ₃ , and the raw material corresponding to the Si element is SiO ₂ .

Further, the molar ratio of Na ₂ CO ₃ , Y ₂ O ₃ , Tb ₄ O ₇ or Eu ₂ O ₃ , Gd ₂ O ₃ , Lu ₂ O ₃ and SiO ₂ is 0.5: (0.01-0.5): (0.01- 0.5): (0.01-0.5): (0.01-0.5): (0.00-0.5): 1 Mix evenly and then sinter at 1100-1300°C for 1 to 6 hours to obtain high quantum efficiency rare earth silicate phosphor.

Green phosphor: Grind Na ₂ CO ₃ , Y ₂ O ₃ , Tb ₄ O ₇ , Gd ₂ O ₃ , Lu ₂ O ₃ , and SiO ₂ according to the stoichiometric ratio and sinter them at high temperature to form NaY _x Gd _y Tb _z Lu _1-xyz SiO ₄ to obtain the high-efficiency rare earth silicate green phosphor.

Red light powder: Na ₂ CO ₃ , Y ₂ O ₃ , Eu ₂ O ₃ , Gd ₂ O ₃ , Lu ₂ O ₃ , SiO ₂ are ground according to stoichiometric ratio and sintered at high temperature to form NaY _x Gd _y Eu _z Lu _1-xyz SiO ₄ to obtain the high-efficiency rare earth silicate red phosphor.

The present invention can obtain high quantum efficiency rare earth silicate phosphor powder only through high-temperature sintering. The preparation method is simple and easy to operate, the preparation cost is low, the profit is good, and it is convenient for large-scale application.

The present invention also provides a high quantum efficiency rare earth silicate phosphor as described in any one of the above items, or an application of the high quantum efficiency rare earth silicate phosphor obtained by any one of the above preparation methods, wherein the high quantum efficiency rare earth silicate phosphor is used in the field of optical devices, and the optical devices include LEDs, optical detectors or lasers.

The beneficial effects of the present invention are as follows:

The high quantum efficiency rare earth silicate phosphor provided by the present invention has a redesigned matrix structure based on the oxyapatite phase, which increases the spacing between rare earth ion doping sites and can be obtained only by high-temperature sintering. It can solve the problems of environmentally unfriendly production, high energy consumption, and low quantum efficiency in the prior art, and realize large-scale production to obtain rare earth silicate phosphors with a narrow luminous bandwidth and high quantum efficiency, ultimately accelerating the completion of carbon peak and carbon neutrality goals.

Description of drawings

In order to more clearly illustrate the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are the drawings of the present invention. For some embodiments, those of ordinary skill in the art can also obtain other drawings based on these drawings without exerting creative efforts.

Figure 1 is a schematic diagram of the preparation process of NaY _x Gd _y Lu _1-xy SiO ₄ phosphor provided in Embodiment 1 of the present invention;

Figure 2 is a fluorescence spectrum diagram of the NaY _{x Tby} Gd _z Lu _1-xyz SiO ₄ phosphor provided in Embodiment 1 of the present invention;

Figure 3 is a CIE color coordinate diagram of the NaY _{x Tby} Gd _z Lu _1-xyz SiO ₄ phosphor provided in Embodiment 1 of the present invention;

Figure 4 is a fluorescence quantum efficiency test chart of the NaY _{x Tby} Gd _z Lu _1-xyz SiO ₄ phosphor provided by Embodiment 1 of the present invention;

Figure 5 is a fluorescence quantum efficiency test chart of the NaY _x Eu _y Gd _z Lu _1-xyz SiO ₄ phosphor provided in Embodiment 3 of the present invention.

Detailed ways

In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention is described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

Unless otherwise specified, the technical means used in the embodiments of the present invention are conventional means well known to those skilled in the art.

In the following examples, unless otherwise specified, all materials and reagents used can be obtained through regular commercial channels.

Example 1

This embodiment provides a method for preparing high-efficiency rare earth silicate-based green phosphor. The preparation process is shown in Figure 1. The specific steps are as follows:

0.5 mol of sodium carbonate, 0.2 mol of yttrium oxide, 0.125 mol of terbium oxide, 0.05 mol of gadolinium oxide and 1 mol of silicon dioxide are ground and mixed, sintered at 1300°C for 2 hours, and the sample is crushed by ball milling to obtain a highly efficient rare earth silicate-based green phosphor with a general chemical formula of NaY _0.4 Tb _0.5 Gd _0.1 SiO ₄ .

Figure 2 is a luminescence spectrum diagram of a lighting device made of high-efficiency rare earth silicate-based green phosphor obtained in this embodiment. It can be seen from the figure that the luminescence peak of the phosphor obtained in this embodiment is concentrated at 550 nm.

Figure 3 is a CIE color coordinate diagram of the photoluminescence spectrum of the high-efficiency rare earth silicate-based green phosphor obtained in this embodiment.

Figure 4 is a quantum efficiency (PLQY) test chart of rare earth silicate-based green phosphors. As can be seen from the figure, the phosphor has a high quantum efficiency, specifically 96.92%.

Example 2

This embodiment provides a method for preparing high-efficiency rare earth silicate-based green phosphor. The preparation process is shown in Figure 1. The specific steps are as follows:

Grind and mix 0.5 mol sodium carbonate, 0.2 mol yttrium oxide, 0.1 mol terbium oxide, 0.05 mol lutetium oxide, 0.05 mol gadolinium oxide, and 1 mol silica, sinter at 1200°C for 4 hours, and crush the sample with a ball mill to obtain high-efficiency rare earth Silicate-based green phosphor, the general chemical formula is NaY _0.4 Gd _0.1 Tb _0.4 Lu _0.1 SiO ₄ .

The quantum efficiency of this phosphor is 85%.

Example 3

This embodiment provides a method for preparing high-efficiency rare earth silicate-based red phosphors. The preparation process is shown in Figure 1. The specific steps are as follows:

Grind and mix 0.5 mol sodium carbonate, 0.2 mol yttrium oxide, 0.2 mol europium oxide, 0.1 mol gadolinium oxide, and 1 mol silica, sinter at 1100°C for 6 hours, and crush the sample by ball milling to obtain high-efficiency rare earth silicate green Optical phosphor, the general chemical formula is NaY _0.4 Eu _0.4 Gd _0.2 SiO ₄ .

Figure 5 is a quantum efficiency (PLQY) test chart of rare earth silicate-based red phosphors. As can be seen from the figure, the phosphor has a high quantum efficiency, specifically 91.5%.

Example 4

This embodiment provides a method for preparing high-efficiency rare earth silicate-based green phosphor. The preparation process is shown in Figure 1. The specific steps are as follows:

Grind and mix 0.5 mol sodium carbonate, 0.15 mol yttrium oxide, 0.125 mol terbium oxide, 0.1 mol gadolinium oxide, and 1 mol silica, sinter at 1300°C for 2 hours, and crush the sample by ball milling to obtain high-efficiency rare earth silicate-based green Optical phosphor, the general chemical formula is NaY _0.3 Tb _0.5 Gd _0.2 SiO ₄ .

The quantum efficiency of this phosphor is 79.3%.

Example 5

This embodiment provides a method for preparing high-efficiency rare earth silicate-based green phosphor. The preparation process is shown in Figure 1. The specific steps are as follows:

0.5 mol of sodium carbonate, 0.2 mol of yttrium oxide, 0.1 mol of terbium oxide, 0.1 mol of gadolinium oxide and 1 mol of silicon dioxide are ground and mixed, sintered at 1300°C for 2 hours, and the sample is crushed by ball milling to obtain a highly efficient rare earth silicate-based green phosphor with a general chemical formula of NaY _0.4 Tb _0.4 Gd _0.2 SiO ₄ .

The quantum efficiency of this phosphor is 88.9%.

Example 6

This embodiment provides a method for preparing high-efficiency rare earth silicate-based green phosphor. The preparation process is shown in Figure 1. The specific steps are as follows:

Grind and mix 0.5 mol sodium carbonate, 0.05 mol yttrium oxide, 0.125 mol terbium oxide, 0.2 mol gadolinium oxide, and 1 mol silica, sinter at 1300°C for 2 hours, and crush the sample by ball milling to obtain high-efficiency rare earth silicate-based green Optical phosphor, the general chemical formula is NaY _0.1 Tb _0.5 Gd _0.4 SiO ₄ .

The quantum efficiency of this phosphor is 55.6%.

Comparative Example 1

This embodiment provides a method for preparing high-efficiency rare earth silicate-based red phosphors. The preparation process is shown in Figure 1. The specific steps are as follows:

Grind and mix 0.5 mol sodium carbonate, 0.2 mol gadolinium oxide, 0.1 mol europium oxide, 0.2 mol lutetium oxide, and 1 mol silica, sinter at 1100°C for 6 hours, and crush the sample with a ball mill to obtain high-efficiency rare earth silicate green Optical phosphor, the general chemical formula is NaGd _0.4 Eu _0.2 Lu _0.4 SiO ₄ .

The quantum efficiency of this phosphor is 60.2%.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that it can still be used Modifications are made to the technical solutions described in the foregoing embodiments, or equivalent substitutions are made to some of the technical features; however, these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims (10)

1. A high quantum efficiency rare earth silicate phosphor, characterized in that the general chemical formula of the phosphor is NaY _x Gd _y M _z Lu _1-xyz SiO ₄ , where 0.02≤x<1, 0.02≤y <1, 0.02≤z<1; M is Tb or Eu. 2 . The high quantum efficiency rare earth silicate phosphor according to claim 1 , wherein 0.1≤x≤0.8, 0.1≤y≤0.6, and 0.3≤z≤0.6. 3. The high quantum efficiency rare earth silicate phosphor according to claim 2, characterized in that, 0.2≤x≤0.6, 0.1≤y≤0.4, 0.3≤z≤0.5. 4. The high quantum efficiency rare earth silicate phosphor according to any one of claims 1 to 3, characterized in that the chemical formula of the phosphor includes high quantum efficiency rare earth silicate green light phosphor and high quantum efficiency Efficient rare earth silicate red phosphor, the green phosphor includes NaY _0.4 Tb _0.5 Gd _0.1 SiO ₄ , NaY _0.3 Tb _0.5 Gd _0.2 SiO ₄ , NaY _0.2 Tb _0.5 Gd _0.3 SiO ₄ , NaY _0.1 Tb _0.5 Gd _0.4 SiO ₄ , NaY _0.4 Tb _0.4 Gd _0.2 SiO ₄ , NaY _0.5 Tb _0.4 Gd _0.1 SiO ₄ , NaY _0.3 Tb _0.4 Gd _0.3 SiO ₄ , NaY _0.4 Tb _0.3 Gd _0.3 SiO ₄ , NaY _0.6 Tb _0.3 Gd _0.1 SiO ₄ , NaY _0.5 One or more of Tb _0.3 Gd _0.2 SiO ₄ , NaY _0.3 Tb _0.5 Gd _0.1 Lu _0.1 SiO ₄ ; red phosphor NaY _0.35 Tb _0.5 Gd _0.1 Lu _0.05 SiO ₄ , NaY _0.4 Eu _0.5 Gd _0.1 SiO _4. NaY _0.3 Eu _0.5 Gd _0.2 SiO ₄ , NaY _0.2 Eu _0.5 Gd _0.3 SiO ₄ , NaY _0.1 Eu _0.5 Gd _0.4 SiO ₄ , NaY _0.4 Eu _0.4 Gd _0.2 SiO ₄ , NaY _0.5 Eu _0.4 Gd _0.1 SiO ₄ , NaY _{0. 3} Eu _0.4 Gd _0.3 SiO ₄ , NaY _0.4 Eu _0.3 Gd _0.3 SiO ₄ , NaY _0.6 Eu _0.3 Gd _0.1 SiO ₄ , NaY _0.5 Eu _0.3 Gd _0.2 SiO ₄ , NaY _0.3 Eu _0.5 Gd _0.1 Lu _0.1 SiO ₄ , NaY _0.35 Eu _{0. 5} Gd _0.1 One or more of Lu _0.05 SiO ₄ . 5. The high quantum efficiency rare earth silicate phosphor according to any one of claims 1 to 4, characterized in that the quantum efficiency of the high quantum efficiency rare earth silicate phosphor is ≥85%, preferably ≥90% . 6. A method for preparing the high quantum efficiency rare earth silicate phosphor according to any one of claims 1 to 5, characterized by comprising: according to the stoichiometry of NaY _x Gd _y M _z Lu _1-xyz SiO ₄ The raw materials corresponding to each element are weighed, mixed and ground, and then sintered at 800-1500°C to obtain high quantum efficiency rare earth silicate phosphor powder. 7. The preparation method of high quantum efficiency rare earth silicate phosphor powder according to claim 6, characterized in that the sintering temperature is 1100-1300°C and the sintering time is 1-6 hours. 8. The preparation method of high quantum efficiency rare earth silicate phosphor according to claim 4, characterized in that the raw material corresponding to the Na element is sodium salt, the raw material corresponding to the Y element is Y ₂ O ₃ , and the Gd element The corresponding raw material is Gd ₂ O ₃ , the raw material corresponding to the M element is Tb ₄ O ₇ or Eu ₂ O ₃ , the raw material corresponding to the Lu element is Lu ₂ O ₃ , and the raw material corresponding to the Si element is SiO ₂ . 9. The preparation method of high quantum efficiency rare earth silicate phosphor according to claim 8, characterized in that, Na ₂ CO ₃ , Y ₂ O ₃ , Tb ₄ O ₇ or Eu ₂ O ₃ , Gd ₂ O _3. The molar ratio of Lu ₂ O ₃ and SiO ₂ is 0.5: (0.01-0.5): (0.01-0.5): (0.01-0.5): (0.01-0.5): (0.00-0.5): 1. Mix evenly, and then Sintering at 1100-1300°C for 1 to 6 hours produces high quantum efficiency rare earth silicate phosphor. 10. A high quantum efficiency rare earth silicate phosphor according to any one of claims 1 to 5, or a high quantum efficiency rare earth silicate phosphor obtained by the preparation method according to any one of claims 6 to 9 The application is characterized in that the high quantum efficiency rare earth silicate phosphor is used in the field of optical devices, and the optical devices include LEDs, optical detectors or lasers.