CN109135731B

CN109135731B - Preparation method of fluorescent powder with controllable light-emitting characteristic and fluorescent powder obtained by preparation method

Info

Publication number: CN109135731B
Application number: CN201811222605.XA
Authority: CN
Inventors: 王树贤; 叶正茂; 吴佳明; 卢晓磊
Original assignee: University of Jinan
Current assignee: University of Jinan
Priority date: 2018-10-19
Filing date: 2018-10-19
Publication date: 2021-05-18
Anticipated expiration: 2038-10-19
Also published as: CN109135731A

Abstract

The invention discloses a preparation method of fluorescent powder with controllable luminescence property and the fluorescent powder, which comprises the following steps: by calcination to give (Eu)³⁺ _x+yA⁺ _yM_1‑x‑2y)₂SiO₄Phosphor, and Eu is obtained by using the phosphor through a microwave reduction method²⁺,Eu³⁺Double-doped silicate phosphor (Eu) — (Eu)²⁺ _xEu³⁺ _yA⁺ _yM_1‑x‑2y)₂SiO₄. The preparation process is simplified and rapid, the energy consumption is low, the process parameters are easy to control and adjust, the condition control is simple, the adjustable range is wide, the controllable modulation of the light output performance of the fluorescent powder can be realized, and different light-emitting requirements can be met. The fluorescent powder has short production period, high production efficiency and lower requirements on equipment and conditions, and is beneficial to realizing the integrated and integrated design of material devices, thereby having the potential of industrialization and batch production.

Description

Preparation method of fluorescent powder with controllable light-emitting characteristic and fluorescent powder obtained by preparation method

Technical Field

The invention relates to a preparation method of a series of fluorescent powders with different luminous characteristics, in particular to a preparation method with simple process and controllable luminous characteristics of the fluorescent powders, and also relates to a series of fluorescent powders with different luminous characteristics and continuously adjustable luminous wave bands from red light to green light, belonging to the technical field of the fluorescent powders and the preparation thereof.

Background

The silicate-based luminescent material has good chemical stability and thermal stability, higher light conversion efficiency and wider excitation band spectrum, and the silicate has rich raw material sources and simple synthesis process, so the silicate-based luminescent material is always a research hotspot for design and development. Europium ion doped silicate phosphors such as Eu²⁺Ion-emitting 214 phase (M)₂SiO₄M = Ca, Sr or Ba) and 315 phases (M)₃SiO₅M = Ca, Sr or Ba) has gradually attracted great attention due to its wide gamut adjustment range and good thermal stability (US 6429583, US 6809347). However, Eu²⁺The ion-doped silicate fluorescent powder has higher color saturation in a yellow-green light region, and the corresponding emission characteristic is generally improved by means of high doping in an orange-red region, so that a series of problems of low fluorescence quenching temperature and the like are brought. The general approach for realizing the light emission requirement is to mix fluorescent powders of different host materials in the system, for example, to prepare white light by using an ultraviolet three-primary-color method. However, the problems of color reabsorption, large energy loss, difficult control of proportioning, different aging rates of different matrixes and the like exist among multi-matrix fluorescent powder, so that the efficiency and the color reducibility are influenced, and the cost is increased. A single matrix material achieves a controllable tuning of the light output properties to the pursuit of the goal.

Eu³⁺Ions are generally selected from⁵D₀→⁷F₁And⁵D₀→⁷F₂the red light emission generated by the transition is dominant, the color purity is high, and the concentration and temperature quenching are small. Binding Eu in silicate matrix²⁺Ion common blue-green light emission and Eu³⁺The red light emission of the ions can effectively realize the color gamut modulation of wide wave bands. However, silicate-based luminescence commonly used at present in high-temperature solid-phase sintering method, sol-gel method, co-combustion method and the likeIn the preparation method of the material, Eu³⁺Ions are very easy to be reduced into Eu in weak reducing atmosphere²⁺Ions, and thus it is difficult to realize Eu²⁺With Eu³⁺Coexistence of ions, making it more difficult to realize Eu²⁺With Eu³⁺Controllable modulation of the ion doping ratio.

At present, Eu is reported to be involved²⁺With Eu³⁺The ion doping proportion regulation and control technology has the defects of complex preparation process, small condition adjustability, uncontrollable fluorescent powder luminescent characteristic and the like. For example, in document 1 (RSC adv., 2017, 7, 1711), the phosphor is sintered three times under a weak reducing atmosphere to Eu²⁺With Eu³⁺The coexistence state of ions, the preparation process is complex and the ion doping proportion is difficult to regulate; document 2 (Angew. chem. int. Ed., 2015, 54, 11501-²⁺With Eu³⁺The regulation and control of the ion doping proportion requires the use of special reducing agents under vacuum conditions and the control of temperature gradients.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a preparation method of fluorescent powder with controllable luminescence characteristics, the method has simple process, wide regulation range and high controllability, and a series of Eu with controllable luminescence wave bands can be obtained by the raw materials of the fluorescent powder and a microwave weak reduction method²⁺,Eu³⁺Double-doped silicate fluorescent powder.

The invention also provides a series of Eu obtained by the method²⁺,Eu³⁺The preparation process of the series of the double-doped silicate fluorescent powder is controllable, the light-emitting wave band can be adjusted from red light to green light, different light output characteristic requirements can be met, and the fluorescent powder has a wide application prospect.

The specific technical scheme of the invention is as follows:

a method for preparing fluorescent powder with controllable luminous characteristics comprises the following steps:

(1) according to (Eu)³⁺ _x+yA⁺ _yM_1-x-2y)₂SiO₄According to the formula of Eu: a: m: si =2(x + y):2y:2(1-x-2y):1, and Eu source, A source, M source, and Si source were weighed and mixedMixing the raw materials, pressing into blocks, presintering, grinding into powder to obtain presintering powder, pressing into blocks, resintering, grinding into powder to obtain (Eu)³⁺ _x+yA⁺ _yM_1-x-2y)₂SiO₄Fluorescent powder;

(2) the (Eu) obtained in the step (1)³⁺ _x+yA⁺ _yM_1-x-2y)₂SiO₄The fluorescent powder is subjected to microwave treatment in the presence of a wave absorbing agent, and partial Eu is treated³⁺Reduction to Eu²⁺The molecular formula is (Eu) through microwave control²⁺ _xEu³⁺ _yA⁺ _yM_1-x-2y)₂SiO₄And the luminous wave band is a series of fluorescent powder with red light to green light change, and the molecular formula of the fluorescent powder can be abbreviated as M₂SiO₄:Eu²⁺,Eu³⁺。

Further, the above method is based on (Eu)³⁺ _x+yA⁺ _yM_1-x-2y)₂SiO₄Difference of phosphors and Eu³⁺The reduction degree is different, a series of fluorescent powder can be obtained, which can also be called Eu²⁺,Eu³⁺The double-doped silicate fluorescent powder is called fluorescent powder for short. The series of fluorescent powder can realize the light-emitting wave band from red light to green light, has wide light-emitting wave band range and can meet the requirements of different light-emitting wave bands.

Further, the present invention (Eu)²⁺ _xEu³⁺ _yA⁺ _yM_1-x-2y)₂SiO₄In the phosphor, preferably, x =0 to 0.1 (excluding 0), y =0 to 0.1, and x + y =0 to 0.2 (excluding 0), i.e., Eu²⁺Is added in an amount of 0-10 at.% (excluding 0), Eu³⁺The addition amount of Eu is 0-10 at.%²⁺、Eu³⁺The total addition amount of the additive is 0-20 at.%.

Further, the M element is at least one of Ca, Sr and Ba, preferably Ca and Sr. The A element is at least one of Li, Na and K, preferably Li, and the A element has the function of charge compensation.

Further, step (ii)In step (1), the Eu source is europium oxide (Eu)₂O₃) Europium chloride (EuCl)₃) Europium sulfate (Eu)₂(SO₄)₃) Europium nitrate (Eu (NO))₃) Europium carbonate (Eu)₂(CO₃)₃) And europium acetate (Eu (CH)₂COOH)₃) Etc., preferably Eu₂O₃。

Further, in the step (1), the A source is halide of A (AX, X = Cl, Br, I), sulfate of A (A)₂SO₄) Nitrate salts of A (ANO)₃) Carbonate of A (A)₂CO₃) Acetate salt of A (ACH)₂COOH), a hydroxide of A (AOH), and the like, preferably a carbonate, and for example, when a is Li, Na, K, the a source is preferably lithium carbonate, sodium carbonate, potassium carbonate, and most preferably lithium carbonate.

Further, in the step (1), the M source is a halide (MX) of M₂X = Cl, Br, I), sulfate of M (MSO)₄) Nitrate of M (NO)₃)₂) M Carbonate (MCO)₃) Acetate salt of M (CH)₂COOH)₂) Hydroxide of M (OH)₂) Etc., preferably M, for example, when M is Ca, Sr, Ba, the M source is preferably calcium carbonate, strontium carbonate, barium carbonate, most preferably calcium carbonate and strontium carbonate.

Further, in the step (1), the Si source is silicon dioxide (SiO)₂) Silicon tetrachloride (SiCl)₄) Silicon carbonate (Si (CO)₃)₂) Tetraethyl orthosilicate (SiC)₈H₂₀O₄) Etc., preferably silica.

Further, in the step (1), the (Eu) is obtained through two-step sintering³⁺ _x+yA⁺ _yM_1-x-2y)₂SiO₄The first sintering step of the fluorescent powder is presintering, and the second sintering step is re-sintering. The process is as follows: firstly, uniformly mixing the Eu source, the A source, the M source and the Si source, pressing the mixture into blocks, and then heatingPre-sintering, grinding into powder, pressing into blocks, heating, re-sintering, grinding into powder to obtain (Eu)³⁺ _x+yA⁺ _yM_1-x-2y)₂SiO₄And (3) fluorescent powder. Preferably, the mixing method of the raw materials is wet mixing, and after mixing, drying in air, and the dispersion medium used may be an alcohol solution. Preferably, the pre-sintering temperature is 800-. Preferably, the temperature for the re-sintering is 1250-1650 ℃, and the sintering time is generally 3-10 h. Further, in the step (1), the raw materials are preferably mixed by wet mixing with an alcohol solution and then dried, the wet mixing time is 1 hour, and the drying is preferably air-dried.

Further, in the step (1), the two times of grinding are carried out until the particle size of the powder is 0.5-15 mm.

Further, in the step (2), (Eu) in the step (1) is subjected to a microwave weak reduction method³⁺ _x+yA⁺ _yM_1-x-2y)₂SiO₄The fluorescent powder is reduced to realize Eu²⁺And Eu³⁺The ion proportion is adjusted, so that the controllable light output characteristic is realized, and an effective means is provided for the preparation of the fluorescent powder meeting different light-emitting requirements. The microwave weak reduction method means that the fluorescent powder is subjected to microwave treatment in the presence of a wave absorbing agent to realize Eu³⁺The controllable reduction of (2).

Further, in the step (2), the microwave frequency is 2-5GHz, the power is preferably 200-800W, and the time is preferably 1-10 min.

Further, in the step (2), the wave absorbing agent is at least one of carbon powder, ferrite, silicon carbide, zirconia and the like, and preferably carbon powder.

Further, in step (2), the wave absorbing agent and (Eu)³⁺ _x+yA⁺ _yM_1-x-2y)₂SiO₄The fluorescent powder is not mixed, namely the fluorescent powder and the fluorescent powder are independently placed, and the fluorescent powder is in the atmosphere of the wave absorbing agent through microwave treatment of the fluorescent powder and the fluorescent powder, so that Eu is realized³⁺Reduction of (2). Microwave reaction device with special structureThe microwave reaction device is preferably a double-layer reactor, the double-layer reactor comprises an outer shell 2 and an inner shell 1 coaxially arranged in the outer shell, and the (Eu) is³⁺ _x+yA⁺ _yM_1-x-2y)₂SiO₄The phosphor 5 is placed in the inner shell, and the wave absorber 3 is placed in the interlayer 4 between the inner shell and the outer shell, and the structure can be referred to fig. 1.

Further, in the step (2), the outer shell and the inner shell of the double-layer reactor are preferably made of a material which allows microwave transmission, such as a corundum crucible, and the shape of the double-layer reactor is approximately cylindrical.

Further, in the step (2), it is preferable that the wave absorber is added in an amount of (Eu)³⁺ _x+yA⁺ _yM_1-x-2y)₂SiO₄5-50 times of the mass of the fluorescent powder.

Furthermore, a series of fluorescent powders with the luminous wave band changing from red light to green light can be obtained according to the method, and the molecular formula is (Eu)²⁺ _xEu³⁺ _yA⁺ _yM_1-x-2y)₂SiO₄Abbreviated as M₂SiO₄:Eu²⁺,Eu³⁺. The series of fluorescent powder is also within the protection scope of the invention. The space group of the series of fluorescent powder is Pna2₁。

Furthermore, the excitation wavelength of the fluorescent powder is 350-430 nm, and the emission wavelength covers 450-750 nm.

Further, the average particle size of the fluorescent powder is 0.5-15 μm.

The invention has the following advantages:

1. the invention selects the components of the fluorescent powder and utilizes Eu at the same time²⁺With Eu³⁺The adjustment of the luminescent property of the silicate fluorescent powder is realized by the fluorescent spectrum characteristics of different ions, and the Eu is controlled by using a microwave weak reduction method²⁺With Eu³⁺The content of ions further realizes green (Eu) in the emission spectrum of the fluorescent powder²⁺Ion) and red (Eu)³⁺Ion) toAnd (4) controllable regulation and control of component content.

2. The preparation process of the fluorescent powder is simplified and rapid, the energy consumption is low, the process parameters are easy to control and adjust, the condition control is simple, the adjustable range is wide, the controllable modulation of the light output performance of the fluorescent powder can be realized, and different light-emitting requirements can be met. The fluorescent powder has short production period, high production efficiency and lower requirements on equipment and conditions, and is beneficial to realizing the integrated and integrated design of material devices, thereby having the potential of industrialization and batch production.

Drawings

FIG. 1 is a schematic view of a microwave reaction apparatus according to the present invention.

FIG. 2, M in examples 1 to 4₂SiO₄:Eu²⁺,Eu³⁺X-ray powder diffraction data of the phosphor.

FIG. 3, M in example 1₂SiO₄:Eu²⁺,Eu³⁺The emission spectrum of the fluorescent powder has an excitation wavelength of 395 nm.

FIG. 4, M in example 2₂SiO₄:Eu²⁺,Eu³⁺The emission spectrum of the fluorescent powder has an excitation wavelength of 395 nm.

FIG. 5, M in example 3₂SiO₄:Eu²⁺,Eu³⁺The emission spectrum of the fluorescent powder has an excitation wavelength of 395 nm.

FIG. 6, M in example 4₂SiO₄:Eu²⁺,Eu³⁺The emission spectrum of the fluorescent powder has an excitation wavelength of 395 nm.

FIG. 7, M in example 5₂SiO₄:Eu²⁺,Eu³⁺The emission spectrum of the fluorescent powder has an excitation wavelength of 395 nm.

FIG. 8, M in examples 1 to 5₂SiO₄:Eu²⁺,Eu³⁺The phosphor and the color coordinates CIE1931 of example 6.

Detailed Description

The invention is further illustrated by the following figures and specific examples, which are meant to be exemplary only and not limiting in their content.

Example 1

Preparation (Eu)²⁺ _0.005Eu³⁺ _0.045A⁺ _0.045M_0.905)₂SiO₄The fluorescent powder comprises the following steps:

with Eu₂O₃、Li₂CO₃、CaCO₃、Sr(NO₃)₂And SiO₂Mixing raw materials according to the molar ratio of Eu to Li (Ca + Sr) to Si of 0.1:0.09:1.81:1, wet-mixing the raw materials with an alcohol solution for 1h, and drying the mixture at room temperature by using a fume hood to obtain uniform mixed powder;

pressing the mixed powder into blocks under 40 MPa, placing into a corundum crucible, sintering at 1100 deg.C for 2 h in air atmosphere, grinding, pressing into blocks, sintering at 1450 deg.C for 6 h in air atmosphere, cooling to room temperature, and grinding to average particle diameter of 0.5-15 μm.

Putting the powder into a small corundum crucible, covering the small corundum crucible with a small corundum crucible cover (non-sealing), putting the small corundum crucible into a large corundum crucible with carbon powder, covering the small corundum crucible to serve as a microwave double-layer reactor, enabling the mass ratio of the powder to the carbon powder to be 1:5, putting the corundum crucible into a household variable frequency microwave oven (frequency of 2.45 GHz), treating for 1 min at 200W, naturally cooling to room temperature, and grinding to obtain (Eu) (Eu²⁺ _0.005Eu³⁺ _0.045A⁺ _0.045M_0.905)₂SiO₄Fluorescent powder with the average grain diameter of 0.5-15 μm.

The obtained phosphor has a composition (Eu) determined by XPS²⁺ _0.005Eu³⁺ _0.045A⁺ _0.045M_0.905)₂SiO₄(ii) a As shown in FIG. 2, the phosphor phase matches the theoretical diffraction, with space group Pna2₁(ii) a As shown in FIG. 3, the emission main peak is located at 580.5 nm/590 nm/594 nm/613 nm/620 nm/623 nm/704 nm; as shown in fig. 8, the CIE color coordinates are (0.60378, 0.35996), which corresponds to red.

Example 2

Preparation (Eu)²⁺ _0.02Eu³⁺ _0.1A⁺ _0.1M_0.78)₂SiO₄The fluorescent powder comprises the following steps:

with Eu₂O₃、Li₂CO₃、CaCO₃、BaCO₃And SiC₈H₂₀O₄Mixing raw materials according to the molar ratio of Eu to Li (Ca + Ba) to Si of 0.24:0.2:1.56:1, wet-mixing the raw materials with an alcohol solution for 1h, and drying the mixture at room temperature by using a fume hood to obtain uniform mixed powder;

pressing the mixed powder into blocks under 40 MPa, placing into a corundum crucible, sintering at 800 deg.C for 5h in air atmosphere, grinding, pressing into blocks, sintering at 1300 deg.C for 10 h in air atmosphere, cooling to room temperature, and grinding to average particle diameter of 0.5-15 μm.

Putting the powder into a small corundum crucible, covering the small corundum crucible with a small corundum crucible cover (non-sealing), putting the small corundum crucible into a large corundum crucible with silicon carbide powder, covering the small corundum crucible to serve as a microwave double-layer reactor, enabling the mass ratio of the powder to the silicon carbide powder to be 1:10, putting the corundum crucible into a household variable frequency microwave oven, treating for 2 min at 600W, naturally cooling to room temperature, and grinding to obtain the product (Eu)²⁺ _0.02Eu³⁺ _0.1A⁺ _0.1M_0.78)₂SiO₄Fluorescent powder with the average grain diameter of 0.5-15 μm.

The obtained phosphor has a composition (Eu) determined by XPS²⁺ _0.02Eu³⁺ _0.1A⁺ _0.1M_0.78)₂SiO₄(ii) a As shown in FIG. 2, the phosphor phase matches the theoretical diffraction, with space group Pna2₁(ii) a As shown in FIG. 4, the emission peak is located at 502 nm/580.5 nm/590 nm/594 nm/613 nm/620 nm/623 nm/704 nm, and the emission band covers 450 nm and 750 nm; as shown in fig. 8, the CIE color coordinates are (0.50486, 0.41010), which corresponds to orange.

Example 3

Preparation (Eu)²⁺ _0.1Eu³⁺ _0.08A⁺ _0.08M_0.74)₂SiO₄The fluorescent powder comprises the following steps:

with Eu₂O₃、K₂CO₃、CaCO₃、SrCO₃And SiO₂Mixing raw materials according to the molar ratio of Eu to K (Ca and Sr) to Si of 0.36:0.16:1.48:1, wet-mixing the raw materials by using an alcohol solution for 1h, and drying the mixture by using a fume hood at room temperature to obtain uniform mixed powder;

pressing the mixed powder into blocks under 40 MPa, placing into a corundum crucible, sintering at 1100 deg.C for 3 h in air atmosphere, grinding, pressing into blocks, sintering at 1450 deg.C for 6 h in air atmosphere, cooling to room temperature, and grinding to average particle diameter of 0.5-15 μm.

Putting the powder into a small corundum crucible, covering the small corundum crucible with a small corundum crucible cover (non-sealing), putting the small corundum crucible into a large corundum crucible with carbon powder, covering the small corundum crucible to serve as a microwave double-layer reactor, enabling the mass ratio of the powder to the carbon powder to be 1:50, putting the corundum crucible into a household variable frequency microwave oven, treating for 7 min at 400W, naturally cooling to room temperature, and grinding to obtain the product (Eu)²⁺ _0.1Eu³ ⁺ _0.08A⁺ _0.08M_0.74)₂SiO₄Fluorescent powder with the average grain diameter of 0.5-15 μm.

The obtained phosphor has a composition (Eu) determined by XPS²⁺ _0.1Eu³⁺ _0.08A⁺ _0.08M_0.74)₂SiO₄(ii) a As shown in FIG. 2, the phosphor phase matches the theoretical diffraction, with space group Pna2₁(ii) a As shown in FIG. 5, the emission peak is located at 502 nm/580.5 nm/590 nm/594 nm/613 nm/620 nm/623 nm/704 nm, and the emission band covers 450 nm and 750 nm; as shown in fig. 8, the CIE color coordinates are (0.42081, 0.43610), which corresponds to yellow.

Example 4

Preparation (Eu)²⁺ _0.08Eu³⁺ _0.02A⁺ _0.02M_0.88)₂SiO₄The fluorescent powder comprises the following steps:

with Eu₂O₃、Li₂CO₃、CaCO₃、SrCO₃And SiO₂As starting materials, the molar ratio of Eu, Li, (Ca + Sr) and Si is 0.2:0.04:1.76:1Mixing, namely wet mixing the raw materials for 1h by using an alcohol solution, and drying the mixture at room temperature by using a fume hood to obtain uniform mixed powder;

pressing the mixed powder into blocks under 40 MPa, placing into a corundum crucible, sintering at 1100 deg.C for 2 h in air atmosphere, grinding, pressing into blocks, sintering at 1650 deg.C for 3 h in air atmosphere, cooling to room temperature, and grinding to average particle diameter of 0.5-15 μm.

Putting the powder into a small corundum crucible, covering the small corundum crucible with a small corundum crucible cover (non-sealing), putting the small corundum crucible into a large corundum crucible with carbon powder, covering the small corundum crucible to serve as a microwave double-layer reactor, putting the corundum crucible into a household variable frequency microwave oven, treating for 8 min at 600W, naturally cooling to room temperature, and grinding to obtain the product (Eu)²⁺ _0.08Eu³ ⁺ _0.02A⁺ _0.02M_0.88)₂SiO₄Fluorescent powder with the average grain diameter of 0.5-15 μm.

The obtained phosphor has a composition (Eu) determined by XPS²⁺ _0.08Eu³⁺ _0.02A⁺ _0.02M_0.88)₂SiO₄(ii) a As shown in FIG. 2, the phosphor phase matches the theoretical diffraction, with space group Pna2₁(ii) a As shown in FIG. 6, the emission peak is located at 510 nm/580.5 nm/590 nm/594 nm/613 nm/620 nm/623 nm/704 nm, and the emission band covers 450 nm and 750 nm; as shown in fig. 8, the CIE color coordinates are (0.36113, 0.46963), which corresponds to yellow-green.

Example 5

Preparation (Eu)²⁺ _0.009Eu³⁺ _0.001A⁺ _0.001M_0.989)₂SiO₄The fluorescent powder comprises the following steps:

with Eu₂CO₃、K₂CO₃、CaCO₃、SrCO₃And SiO₂Mixing Eu, Li, (Ca + Sr) and Si according to a molar ratio of 0.02:0.002:1.978:1 as initial raw materials, wet-mixing the raw materials by using an alcohol solution for 1h, and drying by using a fume hood at room temperature to obtain uniform mixed powder;

pressing the mixed powder into blocks under 40 MPa, placing into a corundum crucible, sintering at 1200 deg.C for 1h in air atmosphere, grinding, pressing into blocks, sintering at 1450 deg.C for 8 h in air atmosphere, cooling to room temperature, and grinding to average particle diameter of 0.5-15 μm.

Putting the powder into a small corundum crucible, covering the small corundum crucible with a small corundum crucible cover (non-sealing), putting the small corundum crucible into a large corundum crucible containing zirconia powder, covering the small corundum crucible to serve as a microwave double-layer reactor, enabling the mass ratio of the powder to the zirconia powder to be 1:20, putting the corundum crucible into a household variable frequency microwave oven, treating for 10 min at 800W, naturally cooling to room temperature, and grinding to obtain the product (Eu)²⁺ _0.009Eu³⁺ _0.001A⁺ _0.001M_0.989)₂SiO₄Fluorescent powder with the average grain diameter of 0.5-15 μm.

The obtained phosphor has a composition (Eu) determined by XPS²⁺ _0.009Eu³⁺ _0.001A⁺ _0.001M_0.989)₂SiO₄The object of which belongs to space group Pna2₁(ii) a As shown in fig. 7, the emission peak is at 515 nm; as shown in fig. 8, the CIE color coordinates are (0.27698, 0.52531), corresponding to green.

Example 6

A phosphor was prepared as in example 4, except that the phosphor had the formula (Eu)²⁺ _0.1Eu³⁺ _0.06A⁺ _0.06M_0.78)₂SiO₄。

The fluorescent powder is used for preparing a luminescent device, and the main working component of the luminescent device is (Eu)²⁺ _0.1Eu³⁺ _0.06A⁺ _0.06M_0.78)₂SiO₄Fluorescent powder and a blue light LED chip with the emission wavelength of 395 nm; the preparation method of the light-emitting device comprises the following steps:

the silicone resin was mixed with (Eu) obtained in example 3²⁺ _0.1Eu³⁺ _0.06A⁺ _0.06M_0.78)₂SiO₄The fluorescent powder is uniformly mixed and uniformly rotated according to the mass ratio of 1:1Coating on 395 nm blue light LED chip, drying and curing to obtain white light LED luminescent device. In the embodiment, no other fluorescent powder is needed to be added, and after the device is powered on, the blue light emitted by the blue light LED and the fluorescent powder are used for absorbing the fluorescent light emitted by the blue light to realize white light output.

As shown in fig. 8, the obtained light emitting device has CIE color coordinates (0.3900, 0.3882), a color rendering index of 82.8, and a correlated color temperature 3975K.

Example 7

Preparation (Eu)²⁺ _0.003Eu³⁺ _0.002A⁺ _0.002M_0.993)₂SiO₄The fluorescent powder comprises the following steps:

with Eu₂O₃、Li₂CO₃、CaCO₃、Sr(NO₃)₂And SiO₂Mixing raw materials according to the molar ratio of Eu to Li (Ca + Sr) to Si of 0.01:0.004:1.986:1, wet-mixing the raw materials by using an alcohol solution for 1h, and drying the mixture by using a fume hood at room temperature to obtain uniform mixed powder;

Putting the powder into a small corundum crucible, covering the small corundum crucible with a small corundum crucible cover (non-sealing), putting the small corundum crucible into a large corundum crucible with carbon powder, covering the small corundum crucible to serve as a microwave double-layer reactor, putting the corundum crucible into a household variable frequency microwave oven, treating for 4 min at 200W, naturally cooling to room temperature, and grinding to obtain the product (Eu)²⁺ _0.003Eu³ ⁺ _0.002A⁺ _0.002M_0.993)₂SiO₄Fluorescent powder with the average grain diameter of 0.5-15 μm.

The obtained phosphor has a composition (Eu) determined by XPS²⁺ _0.003Eu³⁺ _0.002A⁺ _0.002M_0.993)₂SiO₄The object of which belongs to space group Pna2₁(ii) a The emission peak is 503 nm/580.5 nm/590 nm/594 nm/613 nm/620 nm/623 nm/704 nm, the emission band covers 450 and 750 nm, the CIE color coordinates are (0.40823, 0.44196), and the color corresponds to yellow.

Example 8

Preparation (Eu)²⁺ _0.08Eu³⁺ _0.04A⁺ _0.04M_0.84)₂SiO₄The fluorescent powder comprises the following steps:

with Eu₂O₃、Li₂CO₃、CaCO₃、BaCO₃And SiC₈H₂₀O₄Mixing raw materials according to the molar ratio of Eu to Li (Ca + Ba) to Si of 0.24:0.08:1.68:1, wet-mixing the raw materials with an alcohol solution for 1h, and drying the mixture at room temperature by using a fume hood to obtain uniform mixed powder;

Putting the powder into a small corundum crucible, covering the small corundum crucible with a small corundum crucible cover (non-sealing), putting the small corundum crucible into a large corundum crucible with ferrite powder, covering the small corundum crucible with a cover to serve as a microwave double-layer reactor, enabling the mass ratio of the powder to the ferrite powder to be 1:10, putting the corundum crucible into a household variable frequency microwave oven, treating for 7 min at 600W, naturally cooling to room temperature, and grinding to obtain the product (Eu)²⁺ _0.08Eu³⁺ _0.04A⁺ _0.04M_0.84)₂SiO₄Fluorescent powder with the average grain diameter of 0.5-15 μm.

The obtained phosphor has a composition (Eu) determined by XPS²⁺ _0.08Eu³⁺ _0.04A⁺ _0.04M_0.84)₂SiO₄The object of which belongs to space group Pna2₁(ii) a The emission peak is positioned at 508 nm/580.5 nm/590 nm/594 nm/613 nm/620 nm/623 nm/704 nm, the emission band covers 450 and 750 nm, the CIE color coordinate is (0.38647, 0.44915)Corresponding to yellow-green.

Example 9

Preparation (Eu)²⁺ _0.07Eu³⁺ _0.08A⁺ _0.08M_0.77)₂SiO₄The fluorescent powder comprises the following steps:

with Eu₂O₃、K₂CO₃、CaCO₃、SrCO₃And SiO₂Mixing raw materials according to the molar ratio of Eu to K (Ca and Sr) to Si of 0.3:0.16:1.54:1, wet-mixing the raw materials by using an alcohol solution for 1h, and drying the mixture by using a fume hood at room temperature to obtain uniform mixed powder;

pressing the mixed powder into blocks under 40 MPa, placing into a corundum crucible, sintering at 900 deg.C for 2 h in air atmosphere, grinding, pressing into blocks, sintering at 1250 deg.C for 6 h in air atmosphere, cooling to room temperature, and grinding to average particle diameter of 0.5-15 μm.

Putting the powder into a small corundum crucible, covering the small corundum crucible with a small corundum crucible cover (non-sealing), putting the small corundum crucible into a large corundum crucible with ferrite powder, covering the small corundum crucible with a cover to serve as a microwave double-layer reactor, putting the small corundum crucible into a household variable frequency microwave oven, treating for 7 min at 400W, naturally cooling to room temperature, and grinding to obtain the product (Eu)²⁺ _0.07Eu³ ⁺ _0.08A⁺ _0.08M_0.77)₂SiO₄Fluorescent powder with the average grain diameter of 0.5-15 μm.

The obtained phosphor has a composition (Eu) determined by XPS²⁺ _0.07Eu³⁺ _0.08A⁺ _0.08M_0.77)₂SiO₄The object of which belongs to space group Pna2₁(ii) a The emission peak is located at 502 nm/580.5 nm/590 nm/594 nm/613 nm/620 nm/623 nm/704 nm, the emission band covers 450 and 750 nm, the CIE color coordinates are (0.53352, 0.39640), and the emission peak corresponds to orange.

While the foregoing examples are illustrative of specific embodiments of the present invention, it will be appreciated that various other embodiments of the invention are possible and that various changes and modifications may be made by those skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. A preparation method of fluorescent powder with controllable light-emitting characteristics is characterized by comprising the following steps:

(1) according to (Eu)³⁺ _x+yA⁺ _yM_1-x-2y)₂SiO₄According to the formula of Eu: a: m: weighing Eu source, A source, M source and Si source according to the molar ratio of Si =2(x + y) to 2y:2(1-x-2y) to 1, uniformly mixing the raw materials, pressing into blocks, presintering, grinding into powder to obtain presintering powder, pressing into blocks, resintering, grinding into powder to obtain (Eu)³⁺ _x+yA⁺ _yM_1-x-2y)₂SiO₄Fluorescent powder;

(2) the (Eu) obtained in the step (1)³⁺ _x+yA⁺ _yM_1-x-2y)₂SiO₄The fluorescent powder is subjected to microwave treatment in the presence of a wave absorbing agent, and partial Eu is treated³⁺Reduction to Eu²⁺Through microwave control, a series of molecular formulas (Eu) are obtained²⁺ _xEu³⁺ _yA⁺ _yM_1-x-2y)₂SiO₄Fluorescent powder with a light-emitting wave band changing from red light to green light;

x =0-0.1, y =0-0.1, x + y =0-0.2, x does not include 0, x + y does not include 0; m is at least one of Ca, Sr and Ba, A is at least one of Li, Na and K;

in the step (2), the microwave frequency is 2-5GHz, the microwave power is 200-800W, and the microwave time is 1-10 min.

2. The method of claim 1, wherein: m is Ca and Sr; a is Li.

3. The method of claim 1, wherein: in the step (1), the Eu source is at least one of europium oxide, europium chloride, europium sulfate, europium nitrate, europium carbonate and europium acetate; the A source is at least one of halide of A, sulfate of A, nitrate of A, carbonate of A and acetate of A; the M source is at least one of M halide, M sulfate, M nitrate, M carbonate and M acetate; the Si source is at least one of silicon dioxide, silicon tetrachloride, silicon carbonate and tetraethyl orthosilicate.

4. The method of claim 3, wherein: in the step (1), the Eu source is europium oxide; the A source is carbonate of A; the M source is a carbonate of M; the Si source is silicon dioxide.

5. The method of claim 1, wherein: in the step (1), the pre-sintering temperature is 800-1200 ℃; the temperature of the re-sintering is 1250-1650 ℃.

6. The method according to claim 5, wherein: in the step (1), the pre-sintering time is 1-5h, and the re-sintering time is 3-10 h.

7. The method according to claim 5 or 6, wherein: in the step (1), the sintering atmosphere of the pre-sintering and the re-sintering is air.

8. The method of claim 1, wherein: in the step (2), the wave absorbing agent is at least one of carbon powder, ferrite, silicon carbide and zirconia; the wave absorber and (Eu)³⁺ _x+yA⁺ _yM_1-x-2y)₂SiO₄The fluorescent powder is not mixed, namely the fluorescent powder and the fluorescent powder are independently placed, and the Eu is realized through the microwave treatment of the fluorescent powder and the fluorescent powder³⁺Reduction of (2).

9. The method of claim 8, wherein: in the step (2), the wave absorbing agent is carbon powder.

10. The method of claim 1, wherein: in the step (2), the microwave reaction device is a double-layer reactor, the double-layer reactor comprises an outer shell and an inner shell coaxially arranged in the outer shell, and the (Eu) is³⁺ _x+yA⁺ _yM_1-x-2y)₂SiO₄The fluorescent powder is placed in the inner shell, and the wave absorbing agent is placed in the interlayer between the inner shell and the outer shell.

11. The method of claim 1, wherein: in step (2), the wave absorbing agent is mixed with (Eu)³⁺ _x+yA⁺ _yM_1-x-2y)₂SiO₄The mass ratio of the fluorescent powder is 5-50: 1.