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

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-x) Ga2O6: xBi < 3 + >, wherein 0 lt; and x is less than or equal to 0.20. The fluorescent material provided by the invention provides an environment with abundant coordination structures activated by bismuth ions, so that the material can emit light with different colors under excitation of different ultraviolet rays, and the fluorescent material has huge potential in multiple application fields of photoelectric functional materials due to multi-mode points with high luminous efficiency, good stability and easy color adjustment. The fluorescent material provided by the invention can be combined with an ultraviolet LED chip to prepare a fluorescent powder conversion light emitting diode device. The preparation method of the fluorescent material disclosed by the invention is simple in process, easy to operate, green and efficient, low in raw material cost and ultrafast in synthesis, is expected to generate huge social benefits and economic benefits, and is suitable for industrial large-scale production.

Description

Technical Field

[0001] The present invention belongs to the technical field of luminescent materials, and in particular relates to a bismuth ion-doped gallate multicolor fluorescent material, a preparation method and a luminescent device. Background Art

[0002] Nowadays, the research and development of high-efficiency phosphor-converted light-emitting diodes (pc-LEDs) has received extensive attention. Due to its well-known advantages, such as good stability, long life, high luminous efficiency and green energy saving, pc-LEDs are considered to be a new generation of solid-state lighting sources that are indispensable for replacing traditional lighting. Taking white light pc-LEDs as an example, traditional white light pc-LEDs are made of blue LED chips and yellow YAG:Ce 3+ However, the lack of red light in the overall emission results in a low color rendering index (<80) and a high correlated color temperature (>4500K) of white light pc-LEDs. In order to meet the requirements of high-quality lighting, white light pc-LEDs should have a higher color rendering index (>90) and a lower correlated color temperature (2700-4000K). Therefore, researchers are committed to developing phosphors with excellent performance in various colors.

[0003] Among them, Eu doped 2+ 、Ce 3+ and Mn 2+ Phosphor materials stand out, and their tunable luminescence properties are considered to be the most anticipated candidates. 2+ 、Ce 3+ and Mn 2+ Activated phosphors include the commonly used yellow YAG:Ce 3+ Phosphors inevitably reabsorb visible light in the blue and even green regions. Ultimately, the color quality of the generated white light is reduced, and this shortcoming limits their practical applications. Therefore, the research on new high-efficiency phosphors excited by ultraviolet light has developed rapidly, especially the exploration of low-cost non-rare earth activators with easily adjustable luminescence properties has increased rapidly. Summary of the invention

[0004] In order to solve the problems existing in the prior art, the present invention provides a new type of non-rare earth Bi 3+ Activated gallate luminescent material and its preparation method and application. The luminescent material of the present invention has considerable absorption efficiency in the near-ultraviolet region. In addition, compared with the same type of Bi 3+ Activate the luminescent system product, in the present 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-mode characteristics of the activated luminescence can increase the versatility of the luminescent material. Specifically,

[0005] One of the objectives 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 ion (Bi 3+ ) as the activator.

[0006] Another objective 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 grinding the intermediate product obtained in step 2) again sufficiently, calcine it in an air atmosphere at 900 - 1200 °C for 3 - 8 hours, and after cooling, grind it into a uniform powder again sufficiently 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 among strontium单质, strontium oxide and compounds convertible to strontium oxide (for example: the strontium source is strontium单质, the strontium source is a mixture of strontium单质 and strontium oxide, the strontium source is a mixture of 2 compounds convertible to strontium oxide, the strontium source is a mixture of strontium单质 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, strontium sulfide, strontium carbonate, strontium sulfate, strontium phosphate and strontium nitrate.

[0012] Preferably, a charge compensator is further added to the raw material mixture, and the charge compensator provides Li + , Na+ or K + The charge compensator can improve and regulate the performance of the fluorescent material.

[0013] Preferably, the sintering and calcining use a heating device with controllable temperature rise and excellent constant temperature effect, such as a tubular furnace or a muffle furnace.

[0014] Preferably, the sintering or calcining is performed by placing the raw material mixture or the intermediate product in an alumina corundum crucible for high temperature treatment.

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

[0016] A third object of the present invention is to provide a phosphor-converted light-emitting diode (pc-LED) device, which includes an ultraviolet LED chip and the above-mentioned multi-color fluorescent material, and the multi-color 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 250-350 nm.

[0018] Preferably, the fluorescent material is uniformly dispersed in epoxy resin, then covered on the chip by coating or dispensing, and cured by heating.

[0019] The present invention is provided by Bi 3+ Activated gallate multicolor fluorescent material is a new type of non-rare earth luminescent material with easily adjustable luminescence performance. It can be excited by different ultraviolet bands, has good multi-mode application adaptability, and emits visible light of different colors, including blue and yellow. 3+ The luminous region is blue or green, and it is very rare to produce long-wave emission such as yellow or red light. Therefore, the fluorescent material of the present invention, on the basis of having common blue light emission, will have an additional strong yellow light emission, which will be very scarce. The multicolor luminescence phenomenon of this single bismuth-doped system can be attributed to the diversity of the local coordination environment of the developed material. In addition, the preparation method of the multicolor fluorescent material of bismuth ion-doped gallate of the present invention is simple, easy to operate, low cost of raw materials used, ultrafast synthesis, etc., which is expected to produce huge social and economic benefits and is suitable for promotion and industrial use. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The X-ray diffraction (XRD) pattern and standard PDF card of the multicolor fluorescent material prepared by the present 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 specific implementation mode

[0024] The present invention will be described in detail below in conjunction with embodiments. These embodiments are only illustrative and 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 natural 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 results of the multi-color luminescent materials prepared above show that no impurity phase is produced, indicating that the phase is a single pure phase. 2.89 Ga2O6:0.11Bi 3+ (i.e. x = 0.11) as an example to test its performance. Figure 2 As shown, the luminescent material has high luminescence brightness, good levels of excitation and emission range, wide and strong excitation at 290nm and 340nm in the ultraviolet bands, and the best emission peaks are located in the wide yellow light region of ~585nm and the blue light band range of ~445nm, respectively, indicating that it can be well matched with the ultraviolet InGaN semiconductor chip. Figure 3 Sr 2.89 Ga2O6:0.11Bi 3+ The variation of emission intensity of luminescent materials with temperature reflects that Bi 3+ Activate the significant electron-phonon coupling interaction present in this gallate system.

[0028] Example 2: Method of adding charge compensating agent

[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, and about 5 mol% of the additive is weighed to the mixture in the total amount of the reference raw material mixture and fully ground and mixed, and the multicolor luminescent material of the present invention can be prepared under the same synthesis conditions as Example 1. Different types of additives will have a certain regulating and improving effect on the luminescent color and luminescent 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: using the phosphor material of the present invention, a packaging substrate and an ultraviolet InGaN semiconductor chip. The phosphor material is the phosphor material synthesized in the above embodiment 1, and its chemical composition formula is Sr 3-x Ga2O6:xBi 3+ (x = 0.11), that is, Sr 2.89 Ga2O6:0.11Bi 3+The peak wavelength of the ultraviolet InGaN semiconductor core is 310nm. The fluorescent material is evenly dispersed in the epoxy resin, and covered on the InGaN semiconductor chip by coating or dispensing. After high-temperature curing, the circuit is welded to obtain the phosphor-converted light-emitting diode light-emitting device of the present invention. The electroluminescent spectrum of the pc-LED light-emitting device is as follows Figure 4 As shown, the Sr under 310nm chip ultraviolet light excitation is realized 2.89 Ga2O6:0.11Bi 3+ Yellow light emission activated by bismuth ions in the material.

[0032] The conventional techniques and schemes not described in detail in the above embodiments are well known in the art, so they will not be described in detail here. The above embodiments and / or experimental examples describe the preferred embodiments of the present invention in detail, but 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, the technical scheme of the present invention can be subjected to a variety of simple modifications, and these simple modifications all belong to the protection scope of the present invention.

Claims

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 Ga2O6:xBi 3+ , where the value of x is 0 <x≤0.20。 2. The method for preparing the multicolor fluorescent material according to claim 1, characterized in that: The following steps are involved: 1) According to the general formula Sr 3-x Ga2O6:xBi 3+ The raw materials of the strontium source, the gallium source and the bismuth source are accurately weighed by weight according to the stoichiometric ratio, mixed and ground evenly 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 compounds convertible into strontium oxide include chlorides, sulfides, carbonates, sulfates, phosphates and nitrates of strontium.

5. The preparation method according to claim 2, characterized in that: A charge compensator is also added to the raw material mixture, and the charge compensator provides Li + 、Na + or K + The salts include one or more of fluorides, chlorides and carbonates.

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 sintering or calcining is that the raw material mixture or the intermediate product is placed in an alumina corundum crucible for high temperature treatment.

8. A phosphor-converted light-emitting diode device, characterized in that: The invention comprises an ultraviolet LED chip and the multi-color fluorescent material according to claim 1, wherein the multi-color 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 multicolor fluorescent material is uniformly dispersed in epoxy resin and then covered on the chip by coating or dispensing.

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