A gallate multicolor fluorescent material doped with bismuth ions, a preparation method and a light emitting device

Abstract

The application discloses a gallate multicolor fluorescent material doped with bismuth ions, a preparation method and a light emitting device. The chemical formula of the fluorescent material is Sr 3‑x Ga2O6:xBi 3+ , wherein 0

Description

Technical Field

[0001] This invention belongs to the field of luminescent materials technology, specifically relating to a gallate multicolor fluorescent material doped with bismuth ions, its preparation method, and a luminescent device. Background Technology

[0002] Currently, the research and development of high-efficiency phosphor-converted light-emitting diodes (pc-LEDs) have received widespread attention. Due to their well-known advantages, such as good stability, long lifespan, high luminous efficiency, and energy saving, pc-LEDs are considered an indispensable next-generation solid-state lighting source to replace traditional lighting. Taking white pc-LEDs as an example, traditional white pc-LEDs use blue LED chips and yellow YAG:Ce LEDs... 3+ Phosphors are used to manufacture white PC-LEDs. However, insufficient red light component in the overall emission leads to a low color rendering index (<80) and a high correlated color temperature (>4500K) in white PC-LEDs. To meet the requirements of high-quality lighting, white PC-LEDs should have a higher color rendering index (>90) and a lower correlated color temperature (2700-4000K). Therefore, researchers are dedicated to developing phosphors with excellent performance in various colors of light emission.

[0003] Among them, Eu is doped 2+ Ce 3+ and Mn 2+ Phosphor materials have emerged as promising candidates due to their tunable luminescence properties. However, in Eu... 2+ Ce 3+ and Mn 2+ Activated phosphors include commonly used yellow YAG:Ce. 3+ Phosphors inevitably exhibit visible light reabsorption in the blue and even green regions. Ultimately, this reduces the color quality of the generated white light, a drawback that limits their practical applications. Therefore, research on novel, highly efficient phosphors excited by ultraviolet light has rapidly progressed, particularly the exploration of low-cost, non-rare-earth-based activators with easily tunable luminescence properties. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a novel material composed of non-rare earth Bi 3+ Activated gallium-based luminescent materials, their preparation methods, and applications. The luminescent material of this invention exhibits considerable absorption efficiency in the near-ultraviolet region, and further surpasses similar Bi... 3+ Activated luminescent system products, in this invention, Bi 3+In addition to having conventional blue light emission (445 nm), the doped gallate material also has quite rare and robust ultra-wide long-wavelength yellow light emission (FWHM = 174 nm, 585 nm) characteristics, which come from Bi 3+ The multi-modal characteristics of the activated luminescence can increase the versatility of the luminescent material. Specifically,

[0005] One of the purposes of the present invention is to provide a bismuth-ion-doped gallate multicolor fluorescent material, and the chemical composition formula of the multicolor fluorescent material is Sr 3-x Ga2O6:xBi 3+ , where x is the molar ratio of Bi 3+ substituting Sr 3+ , and the value range is 0 < x ≤ 0.20. The novel multicolor luminescent material of the present invention uses gallate as the matrix and trivalent bismuth ions (Bi 3+ ) as the activator.

[0006] Another purpose of the present invention is to provide a preparation method of the above-mentioned multicolor fluorescent material, including the following steps:

[0007] 1) Weigh the raw materials of strontium source, gallium source and bismuth source accurately by weight according to the stoichiometric ratio of the general formula Sr 3-x Ga2O6:xBi 3+ , mix them and grind them evenly to obtain a raw material mixture;

[0008] 2) Pre-sinter the raw material mixture obtained in step 1) in an air atmosphere at 300 - 600 °C for 3 - 6 hours to obtain an intermediate product;

[0009] 3) After the intermediate product obtained in step 2) is ground again sufficiently, calcine it in an air atmosphere at 900 - 1200 °C for 3 - 8 hours, cool it, and then grind it into a uniform powder again to obtain the multicolor fluorescent material.

[0010] Preferably, the sources of the raw materials in step 1) are specifically as follows: the strontium source is one or more substances of elemental strontium, strontium oxide and compounds convertible to strontium oxide (for example: the strontium source is elemental strontium, the strontium source is a mixture of elemental strontium and strontium oxide, the strontium source is a mixture of 2 compounds convertible to strontium oxide, the strontium source is a mixture of elemental strontium and 1 compound convertible to strontium oxide); the gallium source is gallium oxide; the bismuth source is bismuth oxide or a bismuth-containing compound other than bismuth oxide.

[0011] Preferably, the compounds convertible to strontium oxide include strontium chloride, sulfide, carbonate, sulfate, phosphate and nitrate.

[0012] Preferably, a charge compensator is added to the raw material mixture, and the charge compensator is a substance that provides Li + , Na+ or K + These include one or more of fluorides, chlorides, and carbonates. Charge compensators can improve and regulate the performance of fluorescent materials.

[0013] Preferably, the sintering and calcination use a heating device with controllable temperature rise and excellent temperature constantness, such as a tube furnace or a muffle furnace.

[0014] Preferably, the sintering or calcination involves placing a mixture of raw materials or intermediate products in an alumina corundum crucible for high-temperature treatment.

[0015] Preferably, the pre-sintering reaction temperature is 500°C and the reaction time is 4 hours; the calcination reaction temperature is 1030°C and the reaction isothermal time is 5 hours.

[0016] A third objective of this invention is to provide a phosphor-converted light-emitting diode (pc-LED) device, the device comprising an ultraviolet LED chip and the aforementioned multicolor fluorescent material, wherein the multicolor fluorescent material covers the ultraviolet LED chip.

[0017] Preferably, the ultraviolet LED chip is an InGaN semiconductor chip with an emission wavelength in the range of 250-350nm.

[0018] Preferably, the fluorescent material is uniformly dispersed in epoxy resin, then coated or dispensed onto the chip, and cured by heating.

[0019] This invention is made by Bi 3+ Activated gallium carbonate multicolor phosphors are novel, non-rare-earth-based materials with easily tunable luminescence properties. They can be excited by different ultraviolet wavelengths, possess good multimode application adaptability, and emit visible light of different colors, including blue and yellow. Compared to conventional Bi... 3+ The luminescent region is predominantly blue or green, and long-wavelength emission such as yellow or red light is extremely rare. Therefore, the fluorescent material of this invention, in addition to its common blue light emission, possesses a particularly strong yellow light emission, which is highly exceptional. This multicolor luminescence phenomenon in a single bismuth-doped system can be attributed to the diversity of the local coordination environment of the developed material. Furthermore, the preparation method of the bismuth ion-doped gallate multicolor fluorescent material of this invention is simple, easy to operate, uses low-cost raw materials, and allows for ultrafast synthesis, which promises significant social and economic benefits and makes it suitable for widespread industrial application. Attached Figure Description

[0020] Figure 1 X-ray diffraction (XRD) patterns and standard PDF cards of the multicolor fluorescent materials prepared in this invention;

[0021] Figure 2Photoluminescence excitation and emission spectra of the luminescent material of the present invention;

[0022] Figure 3 Thermal stability diagram of the luminescence of the luminescent material of the present invention;

[0023] Figure 4 Schematic diagram of the pc-LED light-emitting device fabricated according to the present invention and its electroluminescence spectrum diagram. Detailed Description of the Invention

[0024] The present invention will be described in detail below with reference to the embodiments. These embodiments are for illustrative purposes only and are not limited to the application scope of the present invention. The present invention is not limited to the following embodiments or implementation manners. Any modifications and variations made without departing from the spirit of the present invention shall be included within the scope of the present invention.

[0025] Example 1: Sr 3-x Ga2O6:xBi 3+ (0 < x ≤ 0.20) Preparation of multicolor fluorescent materials

[0026] According to the chemical formula Sr 3-x Ga2O6:xBi 3+ , 0 < x ≤ 0.20 (in this example, x takes 0.01, 0.03, 0.05, 0.07, 0.09, 0.11, 0.15, 0.20 respectively to prepare the corresponding fluorescent materials: Sr 2.99 Ga2O6:0.01Bi 3+ 、Sr 2.97 Ga2O6:0.03Bi 3+ 、Sr 2.95 Ga2O6:0.05Bi 3+ 、Sr 2.93 Ga2O6:0.07Bi 3+ 、Sr 2.91 Ga2O6:0.09Bi 3+ 、Sr 2.89 Ga2O6:0.11Bi 3+ 、Sr 2.85 Ga2O6:0.15Bi 3+ 、Sr 2.8 Ga2O6:0.2Bi 3+ ), accurately weigh the powder raw materials SrCO3, Ga2O3, and Bi2O3. Place the weighed raw materials in an agate mortar, grind until the raw materials are fully mixed evenly, then transfer them to an alumina corundum crucible, place it in a high-temperature box furnace, and pre-sinter at 500 °C for 4 hours. After cooling, take it out and grind it, then put it back into the box furnace again and sinter at 1030 °C for 5 hours. After naturally cooling to room temperature, take it out and grind it again to obtain the Bi 3+Activated multicolor fluorescent material. The prepared fluorescent material was tested, and the results are as follows:

[0027] like Figure 1 The XRD patterns of the multicolor luminescent materials prepared above confirmed the absence of impurity phases, indicating that the phases were single, pure phases. Using the prepared Sr... 2.89 Ga2O6:0.11Bi 3+ Taking x = 0.11 as an example, its performance was tested. Figure 2 As shown, the luminescent material exhibits high luminescence brightness and a good excitation and emission range. It has a wide range of strong excitation in the ultraviolet bands of 290nm and 340nm, and the optimal emission peaks are located in the wide yellow light region of ~585nm and the blue light band of ~445nm, respectively, indicating that it can be well matched with ultraviolet InGaN semiconductor chips. Figure 3 For Sr 2.89 Ga2O6:0.11Bi 3+ The graph showing the emission intensity of the luminescent material as a function of temperature reflects the effect of Bi. 3+ This activates the significant electron-phonon coupling interactions present in the gallium salt system.

[0028] Example 2: Method for adding charge compensator

[0029] According to the preparation example described in Example 1, after weighing each raw material according to the stoichiometric ratio of each element, one of Li2CO3, Na2CO3, or K2CO3 can be selected as a charge compensator. Approximately 5 mol% of the additive is weighed into the mixture and thoroughly ground and mixed. The multicolor luminescent material of the present invention can be prepared under the same synthesis conditions as in Example 1. Different selections of additives will have a certain controlling and improving effect on the luminescent color and brightness of the final product luminescent material.

[0030] Example 3: Packaging of PC-LED Light-Emitting Device

[0031] A phosphor-converted light-emitting diode (pc-LED) light-emitting device: employing the phosphor material, encapsulation substrate, and ultraviolet InGaN semiconductor chip of this invention. The phosphor material is the phosphor material synthesized in Example 1 above, with the chemical formula Sr... 3-x Ga2O6:xBi 3+ (x = 0.11), i.e., Sr 2.89 Ga2O6:0.11Bi 3+The peak emission wavelength of the ultraviolet InGaN semiconductor chip is ~310nm. The fluorescent material is uniformly dispersed in epoxy resin and coated or dispensed onto the InGaN semiconductor chip. After high-temperature curing, the circuit is soldered to obtain the phosphor-converted light-emitting diode (LED) device of this invention. The electroluminescence spectrum of the PC-LED device is as follows: Figure 4 As shown, Sr under ultraviolet light excitation on a 310nm chip was realized. 2.89 Ga2O6:0.11Bi 3+ Yellow light emission activated by bismuth ions in the material.

[0032] The conventional techniques and solutions not described in detail in the above embodiments are all well known in the art, and therefore will not be elaborated upon here. The above embodiments and / or experimental examples describe the preferred embodiments of the present invention in detail. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, and these simple modifications all fall within the protection scope of the present invention.

Claims

1. A gallate multicolor fluorescent material doped with bismuth ions, characterized in that, The chemical formula of the multicolor fluorescent material is Sr 3-x Ga2O6: x Bi 3+ ,in x The range of values ​​is 0 < x ≤0.

20.

2. The method for preparing the multicolor fluorescent material according to claim 1, characterized in that, Includes the following steps: 1) According to the general formula Sr 3-x Ga2O6: x Bi 3+ The raw materials of strontium source, gallium source and bismuth source were accurately weighed according to the stoichiometric ratio, mixed and ground evenly to obtain a raw material mixture; 2) The raw material mixture from step 1) is pre-sintered in air at 300-600 °C for 3-6 hours to obtain an intermediate product; 3) After thoroughly grinding the intermediate product from step 2), calcine it at 900-1200 ℃ for 3-8 hours in an air atmosphere, cool it, and then grind it thoroughly again into a uniform powder to obtain the multicolor fluorescent material.

3. The preparation method according to claim 2, characterized in that, The specific sources of the raw materials mentioned in step 1) are as follows: The strontium source is one or more substances selected from elemental strontium, strontium oxide, and compounds that can be converted 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 compounds that can be converted into strontium oxide include strontium chlorides, sulfides, carbonates, sulfates, phosphates, and nitrates.

5. The preparation method according to claim 2, characterized in that, The raw material mixture also contains a charge compensator, which is used to provide Li + Na + or K + It includes one or more of fluorides, chlorides and carbonates.

6. The preparation method according to claim 2, characterized in that, The sintering and calcination processes utilize heating devices with controllable temperature rise and excellent temperature control.

7. The preparation method according to claim 6, characterized in that, The sintering or calcination involves placing a mixture of raw materials or intermediate products in an alumina corundum crucible for high-temperature treatment.

8. A phosphor-to-light-emitting diode device, characterized in that, It includes an ultraviolet LED chip and the multicolor fluorescent material of claim 1, wherein the multicolor fluorescent material is coated on the ultraviolet LED chip.

9. The apparatus as claimed in claim 8, characterized in that, The ultraviolet LED chip is an InGaN semiconductor chip with an emission wavelength in the range of 250-350 nm.

10. The apparatus as claimed in claim 8 or 9, characterized in that, The multicolor fluorescent material is uniformly dispersed in epoxy resin and then coated or dispensed onto the chip.

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