CN119307255A - Bismuth-doped gallate multicolor fluorescent material, preparation method and light-emitting device - Google Patents

Abstract

The invention discloses a bismuth ion doped gallate multicolor fluorescent material, a preparation method and a light-emitting device. The chemical formula of the fluorescent material is Sr _3‑xGa₂O₆:xBi³⁺, wherein x is more than 0 and less than or equal to 0.20. The fluorescent material provided by the invention has a rich bismuth ion activated coordination structure environment, so that the material can generate luminescence with different colors under different ultraviolet excitation, and has the characteristics of high luminous efficiency, good stability and easily-adjustable color and multiple modes, so that the fluorescent material has great potential in multiple application fields of photoelectric functional materials. The fluorescent material and the ultraviolet LED chip can be combined to prepare the fluorescent powder conversion LED device. The preparation method of the fluorescent material has the advantages of simple process, easy operation, green and high efficiency, low cost of the used raw materials, ultrafast synthesis, hopeful generation of great social and economic benefits, and suitability for industrialized mass production.

Description

Bismuth ion doped gallate multicolor fluorescent material, preparation method and light-emitting device

Technical Field

The invention belongs to the technical field of luminescent materials, and particularly relates to a bismuth ion doped gallate multicolor fluorescent material, a preparation method and a luminescent device.

Background

Nowadays, research and development of a high-efficiency phosphor-converted light emitting diode (pc-LED), which is considered as an indispensable new generation solid-state lighting source for replacing the conventional lighting due to its well-known advantages such as good stability, long life, high luminous efficiency, green energy saving, etc., have been receiving a lot of attention. Taking a white light pc-LED as an example, a conventional white light pc-LED is manufactured by combining a blue LED chip and a yellow YAG: ce ³⁺ phosphor. However, insufficient red light content in the overall emission results in a low color rendering index (< 80) and a high correlated color temperature (> 4500K) of the white light pc-LED. To meet the requirements of high quality illumination, white light pc-LEDs should have a higher color rendering index (> 90) and a lower correlated color temperature (2700-4000K). Accordingly, researchers have been working to develop phosphors that emit light of various colors with excellent properties.

Among them, phosphor materials doped with Eu ²⁺、Ce³⁺ and Mn ²⁺, whose tunable luminescence properties are considered as currently expected candidates. However, among Eu ²⁺、Ce³⁺ and Mn ²⁺ activated phosphors, including the commonly used yellow YAG Ce ³⁺ phosphor, there is an unavoidable visible light reabsorption phenomenon in the blue and even green regions. Eventually, the color quality of the generated white light is reduced, which has limited their practical application. Therefore, research on novel high-efficiency fluorescent powder excited by ultraviolet light is rapidly developed, and especially, research on low-cost non-rare earth activator with easily-regulated luminous performance is rapidly increased.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides a novel gallate luminescent material activated by non-rare earth Bi ³⁺, and a preparation method and application thereof. Compared with the same type of Bi ³⁺ activated luminescent system products, the Bi ³⁺ doped gallate material has the characteristics of quite rare and strong ultra-wide long-wavelength band yellow light emission (FWHM=174 nm,585 nm) besides the conventional blue light emission (445 nm), and the multi-mode characteristic of the Bi ³⁺ activated luminescence can increase the versatility of the luminescent material. In particular, the method comprises the steps of,

One of the purposes of the invention is to provide a bismuth-ion-doped gallate multicolor fluorescent material, wherein the chemical composition formula of the multicolor fluorescent material is Sr _3-xGa₂O₆:xBi³⁺, wherein x is the molar ratio of Bi ³⁺ to Sr ³⁺, and the value range is 0< x less than or equal to 0.20. The novel multicolor luminescent material of the invention takes gallate as a matrix and trivalent bismuth ion (Bi ³⁺) as an activator.

The second object of the present invention is to provide a method for preparing the multicolor fluorescent material, comprising the following steps:

1) Respectively and accurately weighing raw materials of a strontium source, a gallium source and a bismuth source according to the stoichiometric ratio of the general formula Sr _3-xGa₂O₆:xBi³⁺, mixing and grinding uniformly to obtain a raw material mixture;

2) Presintering the raw material mixture in the step 1) in an air atmosphere at 300-600 ℃ for 3-6 hours to obtain an intermediate product;

3) And (3) fully grinding the intermediate product obtained in the step (2) again, calcining for 3-8 hours at 900-1200 ℃ in air atmosphere, cooling, and fully grinding again into uniform powder to obtain the multicolor fluorescent material.

Preferably, the source of the raw material in the step 1) is specifically selected from one or more of simple substance strontium, oxide of strontium and compound convertible to strontium oxide (for example, strontium source is simple substance strontium, strontium source is mixture of simple substance strontium and strontium oxide, strontium source is mixture of 2 compounds convertible to strontium oxide, strontium source is mixture of simple substance strontium and 1 compound convertible to strontium oxide), gallium source is gallium oxide, bismuth source is bismuth oxide or bismuth-containing compound except bismuth oxide.

Preferably, the strontium oxide convertible compounds include strontium chloride, sulfide, carbonate, sulfate, phosphate and nitrate.

Preferably, a charge compensator is also added to the raw material mixture, the charge compensator being one or more of fluoride, chloride and carbonate providing Li ⁺、Na⁺ or K ⁺. The charge compensation agent can improve and regulate the performance of the fluorescent material.

Preferably, the sintering and calcining use heating means such as a tube furnace or a muffle furnace with controllable temperature rise and excellent constant temperature effect.

Preferably, the sintering or calcining is carried out by placing the raw material mixture or the intermediate product into an alumina corundum crucible for high-temperature treatment.

Preferably, the reaction temperature of the pre-sintering is 500 ℃, the reaction time is 4 hours, the reaction temperature of the calcining is 1030 ℃, and the reaction constant temperature time is 5 hours.

It is a further object of the present invention to provide a phosphor converted light emitting diode (pc-LED) device comprising an ultraviolet LED chip and the above mentioned multicolor fluorescent material, which is covered on the ultraviolet LED chip.

Preferably, the ultraviolet LED chip is an InGaN semiconductor chip with an emission wavelength in the range of 250-350 nm.

Preferably, the fluorescent material is uniformly dispersed in the epoxy resin, then coated or dispensed on the chip, and cured by heating.

The gallate multicolor fluorescent material activated by Bi ³⁺ is a novel non-rare earth luminescent property easily-adjustable material, can be excited by different ultraviolet bands, has good multimode application adaptability, and emits visible light with different colors, including blue light and yellow light. It is very rare that long-wave emission of yellow light or red light, etc. can be generated compared to the conventional Bi ³⁺ light-emitting region in blue or green light. Therefore, the fluorescent material of the present invention has a strong yellow light emission which is additionally possessed by the fluorescent material on the basis of possessing a common blue light emission. The polychromatic emission phenomenon of this single bismuth doped system can be attributed to the diversity of the local coordination environment of the materials developed. In addition, the preparation method of the bismuth ion doped gallate multicolor fluorescent material has the advantages of simplicity, easiness in operation, low cost of raw materials used, ultrafast synthesis and the like, is expected to generate great social and economic benefits, and is suitable for popularization and industrialization.

Drawings

FIG. 1 is an X-ray diffraction (XRD) pattern of a multicolor fluorescent material prepared in accordance with the present invention, and a standard PDF card;

FIG. 2 is a photo-excitation and emission spectrum of a luminescent material of the present invention;

FIG. 3 is a luminescent thermal stability diagram of a luminescent material of the present invention;

FIG. 4 is a schematic diagram of a pc-LED light-emitting device and an electroluminescence spectrum thereof.

Detailed Description

The present invention will be described in detail with reference to examples, which are illustrative only and are not limiting the scope of application of the present invention. The present invention is not limited to the following embodiments or examples, and modifications and variations made without departing from the spirit of the present invention are intended to be included in the scope of the present invention.

Example 1 preparation of Sr _3-xGa₂O₆:xBi³⁺ (0 < x.ltoreq.0.20) multicolor fluorescent material

According to the chemical formula Sr _3-xGa₂O₆:xBi³⁺, 0< x less than or equal to 0.20 (in the embodiment, x is respectively 0.01, 0.03, 0.05, 0.07, 0.09, 0.11, 0.15 and 0.20, the stoichiometric ratio of each element in the corresponding fluorescent material ：Sr_2.99Ga₂O₆:0.01Bi³⁺、Sr_2.97Ga₂O₆:0.03Bi³⁺、Sr_2.95Ga₂O₆:0.05Bi³⁺、Sr_2.93Ga₂O₆:0.07Bi³⁺、Sr_2.91Ga₂O₆:0.09Bi³⁺、Sr_2.89Ga₂O₆:0.11Bi³⁺、Sr_2.85Ga₂O₆:0.15Bi³⁺、Sr_2.8Ga₂O₆:0.2Bi³⁺) is prepared, the powder raw material SrCO ₃,Ga₂O₃,Bi₂O₃ is accurately weighed, the weighed raw materials are placed in an agate mortar, the raw materials are ground until the raw materials are fully and uniformly mixed, then transferred into an alumina corundum crucible, placed in a high-temperature box furnace, pre-sintered for 4 hours at 500 ℃, cooled and taken out, ground, then placed in the box furnace again and sintered for 5 hours at a constant temperature at 1030 ℃, naturally cooled to room temperature, taken out, ground again, and the Bi ³⁺ activated multicolor fluorescent material is obtained, and the obtained fluorescent material is detected as follows:

As shown in fig. 1, the XRD pattern results of the above-prepared multicolor luminescent materials demonstrate that no impurity phase is generated, and the explanatory phase is a single pure phase. Taking the prepared Sr _2.89Ga₂O₆:0.11Bi³⁺ (i.e. x=0.11) as an example for testing the performance, as shown in fig. 2, the luminescent material has high luminescent brightness, has good level excitation and emission range, has wider strong excitation at ultraviolet bands of 290nm and 340nm, and has optimal emission peaks respectively located in a wide yellow light region of 585nm and a blue light band range of 445nm, which indicates that the luminescent material can be well matched with an ultraviolet InGaN semiconductor chip. Fig. 3 is a graph of the emission intensity of Sr _2.89Ga₂O₆:0.11Bi³⁺ luminescent material as a function of temperature, reflecting the significant electroacoustic sub-coupling interactions that Bi ³⁺ has to activate in this gallate system.

Example 2 method of adding Charge Compensation Agents

According to the preparation example described in example 1, after weighing each raw material according to the element metering ratio, either Li ₂CO₃、Na₂CO₃ or K ₂CO₃ can be selected as a charge compensator, and about 5mol% of the additive is weighed into the mixture in the total amount of the control raw material mixture and sufficiently ground and mixed, the multicolor luminescent material of the present invention can be prepared under the same synthesis conditions as in example 1. The variety of the additive is different, which can have certain regulation and improvement effect on the luminescent color and the luminescent brightness of the final product luminescent material.

Example 3 packaging of pc-LED light emitting device

A luminescent device of a fluorescent powder conversion light-emitting diode (pc-LED) adopts the fluorescent powder material, a packaging substrate and an ultraviolet InGaN semiconductor chip. The phosphor material is the phosphor material synthesized in the above embodiment 1, and has a chemical composition formula of Sr _3-xGa₂O₆:xBi³⁺ (x=0.11), namely Sr _2.89Ga₂O₆:0.11Bi³⁺, and the peak wavelength of light emission of the ultraviolet InGaN semiconductor core is about 310nm. The fluorescent material is uniformly dispersed in epoxy resin, and is coated or glued on an InGaN semiconductor chip, and after high-temperature curing, a circuit is welded, so that the fluorescent powder conversion LED luminescent device is obtained. The electro-luminescence spectrum of the pc-LED light-emitting device is shown in fig. 4, and the bismuth ion activated yellow light emission in the Sr _2.89Ga₂O₆:0.11Bi³⁺ material under the excitation of 310nm chip ultraviolet light is realized.

Conventional techniques and schemes not described in detail in the above embodiments are well known in the art, and will not be described in detail here. The above examples and/or experimental examples describe in detail preferred embodiments of the present invention, but the present invention is not limited to the specific details of the above embodiments, and various simple modifications may be made to the technical solution of the present invention within the scope of the technical concept of the present invention, and all the simple modifications are within the scope of the protection of the present invention.

Claims (10)

1. A bismuth-ion-doped gallate multicolor fluorescent material, characterized in that the chemical composition formula of the multicolor fluorescent material is Sr _3-x Ga ₂ O ₆ :xBi ³⁺ , wherein the value range of x is 0<x≤0.20. 2. The method for preparing the multicolor fluorescent material according to claim 1, characterized in that it comprises the following steps: 1) accurately weighing raw materials of strontium source, gallium source and bismuth source according to the stoichiometric ratio of the general formula Sr _3-x Ga ₂ O ₆ :xBi ^3+, mixing and grinding them uniformly to obtain a raw material mixture; 2) pre-sintering the raw material mixture of step 1) at 300-600° C. for 3-6 hours in an air atmosphere to obtain an intermediate product; 3) The intermediate product of step 2) is fully ground again, calcined at 900-1200° C. for 3-8 hours in an air atmosphere, and then fully ground again into a uniform powder after cooling to obtain the multicolor fluorescent material. 3. The preparation method according to claim 2, characterized in that the sources of the raw materials described in step 1) are specifically as follows: The strontium source is one or more substances selected from the group consisting of simple strontium, strontium oxide and compounds convertible into strontium oxide; the gallium source is gallium oxide; and the bismuth source is bismuth oxide or a bismuth-containing compound other than bismuth oxide. 4. The preparation method according to claim 3, characterized in that the compound convertible into strontium oxide includes chloride, sulfide, carbonate, sulfate, phosphate and nitrate of strontium. 5. The preparation method according to claim 2, characterized in that a charge compensator is further added to the raw material mixture, and the charge compensator is one or more of fluoride, chloride and carbonate that provide Li ⁺ , Na ⁺ or K ⁺ . 6. The preparation method according to claim 2, characterized in that the sintering and calcining use a heating device with controllable temperature rise and excellent constant temperature effect. 7. The preparation method according to claim 6, characterized in that the sintered or calcined raw material mixture or intermediate product is placed in an alumina corundum crucible for high temperature treatment. 8. A phosphor-converted light-emitting diode device, comprising an ultraviolet LED chip and the multicolor fluorescent material of claim 1, wherein the multicolor fluorescent material covers the ultraviolet LED chip. 9. The device according to claim 8, characterized in that the ultraviolet LED chip is an InGaN semiconductor chip with an emission wavelength in the range of 250-350nm. 10. The device according to claim 8 or 9, characterized in that the multi-color fluorescent material is uniformly dispersed in epoxy resin and then covered on the chip by coating or dispensing.