Purple light excited orange fluorescent powder and application thereof

Abstract

The application relates to an orange fluorescent powder excited by purple light and application, and the chemical formula of the orange fluorescent powder is Zn4CdS5. A Zn-containing compound and a Cd-containing compound are uniformly ground and mixed, are sealed into a vacuum quartz tube for calcination, and the orange fluorescent powder is obtained after cooling, wherein the Zn-containing compound and the Cd-containing compound contain S elements. Compared with the prior art, the orange fluorescent powder prepared by the application has strong emission intensity and the advantages of stable physical and chemical properties, and can be widely matched with commercial purple light LED chips.

Description

Technical Field

[0001] This invention relates to the field of phosphor preparation technology, and in particular to an orange phosphor excited by violet light and its application. Background Technology

[0002] With the rapid development of modern display technology, optoelectronic devices, and lighting technology, orange-red emitting phosphors have attracted increasing attention due to their important roles in displays and lighting. Sulfide phosphors, with their high quantum efficiency, good thermal stability, and resistance to environmental changes, have become a promising research direction. However, traditional sulfide phosphors still suffer from limitations in luminescence efficiency, insufficient color purity, poor material stability, and complex preparation processes during synthesis. Therefore, many researchers are dedicated to improving the luminescence performance and application effects of sulfide phosphors by refining synthesis methods, optimizing doping elements, and exploring novel synthesis pathways.

[0003] Patent publication number CN112892563A discloses an F-doped ZnCdS solid solution photocatalytic material, its preparation method, and its application. First, nano-flower-like ZnCdS is obtained through hydrothermal synthesis, and then F-doped ZnCdS is obtained through a second hydrothermal method. However, this ZnCdS is used as a catalyst for photocatalysis, and the concept of excitation / emission wavelength is not involved. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the existing technology and provide a purple-excited orange phosphor with higher luminous efficiency, better color purity and stronger environmental adaptability, as well as its application. The prepared orange phosphor has a strong emission intensity and the advantage of stable physicochemical properties, and can be widely matched with commercial purple LED chips.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] One of the technical solutions of the present invention is to provide an orange phosphor excited by violet light, the chemical formula of which is Zn4CdS5.

[0007] Furthermore, the emission wavelength of the orange phosphor is 450–800 nm.

[0008] Furthermore, the center wavelength of the emission band of the orange phosphor is 650~660nm.

[0009] Furthermore, the excitation wavelength of the orange phosphor is 200~600nm, which is located in the violet to red light region.

[0010] The second technical solution of the present invention is to provide a method for preparing an orange phosphor excited by violet light, wherein a Zn-containing compound and a Cd-containing compound are ground and mixed evenly, sealed in a vacuum quartz tube and calcined, and cooled to obtain the orange phosphor, wherein the Zn-containing compound and the Cd-containing compound contain sulfur.

[0011] Furthermore, the Zn-containing compound includes Zn-containing sulfides;

[0012] Cd-containing compounds include Cd-containing sulfides.

[0013] Furthermore, the Zn-containing compound includes ZnS;

[0014] Cd-containing compounds include CdS.

[0015] Furthermore, the mass ratio of the Zn-containing compound to the Cd-containing compound is (3.2~5.5):(0.2~1.8).

[0016] Furthermore, the mass ratio of the Zn-containing compound to the Cd-containing compound is (4~4.7):(0.3~1.1).

[0017] Furthermore, the calcination temperature in the quartz tube is 300~1000℃.

[0018] Furthermore, the calcination is carried out in stages, with the first stage calcination temperature being 300~500℃, the second stage calcination temperature being 750~1000℃, and the third stage calcination temperature being 450~550℃.

[0019] Furthermore, the specific process of segmented calcination is as follows:

[0020] First stage of calcination: Heat to 300~500℃ within 600min, and hold for 800~1200min;

[0021] The second stage of calcination: the temperature is raised to 750-1000℃ within 200-400 minutes, and held for 200-400 minutes;

[0022] The third stage of calcination: After cooling to 450-550℃ for 300-500 minutes, the temperature is held for 150-250 minutes.

[0023] Furthermore, the heating rate of the first stage of calcination is 0.5~1℃ / min, the heating rate of the second stage of calcination is 1.5~2℃ / min, and the cooling rate of the third stage of calcination is 0.2~0.5℃ / min.

[0024] Furthermore, the grinding time is 20-50 minutes.

[0025] The third technical solution of the present invention is to provide an application of violet light-excited orange phosphor in the field of lighting devices, wherein the orange phosphor is assembled with a violet light chip to form an infrared detector device.

[0026] Compared with the prior art, the present invention has the following advantages:

[0027] (1) The phosphor described in this invention can emit orange light with a spectral range of 450~800nm ​​and a center wavelength of 650~660nm under violet light excitation, and this has not been reported before.

[0028] (2) Compared with the prior art, the present invention is a sulfur-based self-luminous orange phosphor, which has the advantages of stable physicochemical properties and high cost performance. At the same time, the orange phosphor can be prepared by conventional solid-phase reaction method, which has the characteristics of simple preparation process and is conducive to industrial production. It has good performance and can be a candidate material for wide application.

[0029] (3) The purple light-excited orange phosphor described in this invention can be well matched with existing commercial purple light LED chips and is suitable for applications such as purple light chip white light LED, purple light chip solar LED, and purple light chip full spectrum LED.

[0030] (4) Since the orange phosphor of the present invention is self-luminous, it avoids problems such as limited luminous efficiency caused by concentration quenching. Attached Figure Description

[0031] Figure 1 The photoexcitation-emission spectrum of Case 1;

[0032] Figure 2 The photoluminescence spectra of Cases 1-3 are shown;

[0033] Figure 3 The XRD pattern for implementing Case 1. Detailed Implementation

[0034] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments. All other embodiments obtained by those skilled in the art based on the given embodiments without creative effort are within the scope of protection of this application. Unless otherwise specified, the reagents, methods, instruments, and equipment used in the present invention are conventional reagents, methods, instruments, and equipment in the art.

[0035] Implementation Case 1

[0036] 1. Select ZnS and CdS as starting materials with a mass ratio of 4.6788:0.4334. Weigh out the two materials separately and control the total mass of the mixture to be about 5g.

[0037] 2. Grind the above raw material mixture in an agate mortar for about 30 minutes until the material is evenly mixed. Then, load the mixture into a quartz tube and vacuum seal it. Place the quartz tube containing the raw material into a muffle furnace and heat it to 400°C in about 600 minutes at a heating rate of about 0.6°C / min. Hold it at that temperature for about 1000 minutes. Then, heat it to 750°C in about 300 minutes at a heating rate of about 1.7°C / min. Hold it at that temperature for about 360 minutes. Then, cool it to 500°C in about 400 minutes at a cooling rate of about 0.63°C / min. Finally, cool it to room temperature with the furnace to obtain the target product Zn4CdS5.

[0038] 3. Use a fluorescence spectrometer (HITACHI F-7000) to test the spectral properties of the phosphor in this system, such as... Figure 1 (The curve on the left is the excitation spectrum, and the curve on the right is the emission spectrum.) Figure 2 As shown in the figure. The results indicate that the phosphor in this system has a broad excitation band, covering the ultraviolet to green light region (300~550nm), with a peak value near 384nm. The high spectral peak indicates that it can be effectively excited by ultraviolet and violet light chips, showing good matching with n-UV LED chips. Under excitation by a 400nm violet light source, the phosphor emits bright orange light, with an emission spectrum consisting of a broad emission band (450~800nm) and a peak value at 652nm. The prepared orange phosphor exhibits strong violet light response with high emission intensity and possesses stable physicochemical properties, enabling it to be widely matched with commercial near-ultraviolet LED chips. Figure 3 The XRD pattern of the sample matched well with the Zn4CdS5 standard, thus confirming that the synthesized sample was Zn4CdS5 and not other substances.

[0039] Implementation Case 2

[0040] 1. Select ZnS and CdS as starting materials with a mass ratio of 4.6788:0.4334. Weigh out the two materials separately and control the total mass of the mixture to be about 5g.

[0041] 2. Grind the above raw material mixture in an agate mortar for 30 minutes until the material is evenly mixed. Then, load the mixture into a quartz tube and vacuum seal it. Place the quartz tube containing the raw material into a muffle furnace and heat it to 400°C in about 600 minutes at a heating rate of about 0.6°C / min. Hold the temperature for about 1000 minutes. Then, heat it to 800°C in about 300 minutes at a heating rate of about 1.7°C / min. Hold the temperature for about 360 minutes. Then, cool it to 500°C in about 400 minutes at a cooling rate of about 0.63°C / min. Finally, cool it to room temperature with the furnace to obtain the target product.

[0042] 3. Use a fluorescence spectrometer (HITACHI F-7000) to test the spectral properties of the phosphor in this system, such as... Figure 2 The results show that the phosphor in this system has a broad excitation band, covering the ultraviolet to green light region (300~550nm), with a peak value near 383nm. The high spectral peak indicates that it can be effectively excited by ultraviolet and violet light chips, showing good matching with n-UV LED chips. Under excitation by a 400nm violet light source, the phosphor emits bright orange light, with an emission spectrum consisting of a broad emission band (450~800nm) and a peak value at 655nm. The prepared orange phosphor exhibits strong violet light response with high emission intensity and possesses stable physicochemical properties, making it widely compatible with commercial near-ultraviolet LED chips.

[0043] Implementation Case 3

[0044] 1. Select ZnS and CdS as starting materials with a mass ratio of 4.6788:0.4334. Weigh out the two materials separately and control the total mass of the mixture to be about 5g.

[0045] 2. Grind the above raw material mixture in an agate mortar for 30 minutes until the material is evenly mixed. Then, load the mixture into a quartz tube and vacuum seal it. Place the quartz tube containing the raw material into a muffle furnace and heat it to 400°C in 600 minutes at a heating rate of 0.6°C / min. Hold the temperature for 1000 minutes. Then, heat it to 50°C in 300 minutes at a heating rate of 1.7°C / min. Hold the temperature for 300 minutes. Then, cool it to 500°C in 400 minutes at a cooling rate of 0.63°C / min. Finally, cool it to room temperature in the furnace to obtain the target product.

[0046] 3. Use a fluorescence spectrometer (HITACHI F-7000) to test the spectral properties of the phosphor in this system, such as... Figure 2As shown in the figure. The results indicate that the phosphor in this system has a broad excitation band, covering the ultraviolet to green light region (300~550nm), with a peak value near 385nm. The high spectral peak value indicates that it can be effectively excited by ultraviolet and violet light chips, and it matches well with n-UV LED chips. Under excitation by a 400nm violet light source, the phosphor emits bright orange light, with an emission spectrum consisting of a broad emission band (450~800nm) and a peak value at 651nm. The prepared orange phosphor has a strong violet light response with high emission intensity and stable physicochemical properties, and can be widely matched with commercial near-ultraviolet LED chips.

[0047] Comparison Case 1

[0048] Using ZnS from Implementation Case 1, the spectral properties were tested with a fluorescence spectrometer (HITACHI F-7000), and it was found that it did not emit light.

[0049] Comparison Case 2

[0050] Using CdS from Implementation Case 1, the spectral properties were tested with a fluorescence spectrometer (HITACHI F-7000), and it was found that it did not emit light.

[0051] Comparison Case 3

[0052] ZnS:Cd was synthesized according to (Wang W, Germanenko I, El-Shall MS. Room-temperature synthesis and characterization of nanocrystalline CdS, ZnS, and CdxZn1-xS[J]. Chemistry of Materials, 2002, 14(7): 3028-3033). The preparation process is as follows:

[0053] An appropriate amount of sulfur powder (CAS No. 7704-34-9, powder, 99.98% trace metals basis, Shanghai Maclean Biochemical Technology Co., Ltd.) was added to a flask containing 50 mL of tetrahydrofuran (THF). After magnetic stirring for 5 minutes, the mixture became a colorless and transparent solution. Stoichiometric amounts of CdCl2 and ZnCl2 powder were added to the flask, and a white suspension was formed after stirring. The suspension turned pale yellow after the addition of potassium borohydride. After stirring for 12 hours, a yellow precipitate formed. This precipitate was filtered and washed several times successively with carbon disulfide, ethanol, and distilled water to remove possible impurities such as potassium chloride and excess sulfur. The precipitate was then dried at room temperature for 12 hours to obtain ZnS:Cd.

[0054] Using a fluorescence spectrometer (HITACHI F-7000), the emission wavelength was measured to be between 400-700 nm, which is completely different from the spectrum of Zn4CdS5 in Implementation Case 1.

[0055] Comparison Case 4

[0056] Compared to Implementation Case 1, most aspects were the same, except that ZnS and CdS were used as starting materials in a mass ratio of 0.9775:1.4447. The two materials were weighed separately, and the total mass of the mixture was controlled to be approximately 5g. ZnCdS2 was synthesized, and its spectral properties were tested using a fluorescence spectrometer (HITACHI F-7000). It was found that the optimal excitation / emission wavelengths of both were completely different from those of Zn4CdS5 in Implementation Case 1.

[0057] Comparison Case 5

[0058] Compared to Implementation Case 1, most aspects are the same, except that the mixed raw materials are heated to 750°C in a muffle furnace at a heating rate of 5°C / h, held at that temperature for 1360 minutes, and then cooled to 500°C at a cooling rate of 5°C / h for 400 minutes. Finally, the furnace is cooled to room temperature. Measurements show that the XRD pattern indicates ZnS and CdS as the starting materials. The quartz tube can withstand a maximum temperature of 1000°C, but in air, the sulfides will oxidize, preventing the synthesis of the target product Zn4CdS5. At low temperatures (<300°C), the melting point of the sulfides is not reached, the system does not react, and the target product Zn4CdS5 cannot be synthesized.

[0059] Comparison Case 6

[0060] The results were largely the same as in Implementation Case 1, except that Zn4CdS5 could not be synthesized by replacing CdS with CdCl2.

[0061] Comparison Case 7

[0062] The results were largely the same as in Implementation Case 1, except that Zn4CdS5 was not synthesized when ZnS was replaced with ZnNO3.

[0063] Table 1 shows the relevant preparation parameters for implementation cases 1-3 and comparative cases 3 and 4.

[0064] Table 1. Relevant preparation parameters for implementation cases 1-3 and comparative cases 3 and 4

[0065]

[0066] As shown in the table above, Zn4CdS5 phosphor can emit orange light with a spectral range of 450~800nm ​​and a center wavelength of 650~660nm under violet light excitation. It has a strong violet light response with high emission intensity. Under 400nm violet light source excitation, the phosphor emits strong orange light and has stable physicochemical properties.

[0067] Since no activator is required for luminescence, this material avoids the problem of reduced luminescence efficiency due to concentration quenching. In addition, it also solves the problem of nonradiative transitions caused by the close proximity of luminescence centers, resulting in higher color purity.

[0068] Although the present invention has been described in detail above with general descriptions, specific embodiments, and experiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A purple light-excited orange phosphor, characterized in that, The chemical formula of this orange fluorescent powder is Zn4CdS5; The orange phosphor is prepared by grinding and mixing a Zn-containing compound and a Cd-containing compound evenly, sealing them in a vacuum quartz tube, calcining them, and cooling them to obtain the orange phosphor. The Zn-containing compound and the Cd-containing compound contain sulfur (S), the Zn-containing compound being ZnS and the Cd-containing compound being CdS. The mass ratio of the Zn-containing compound to the Cd-containing compound is (3.2~5.5):(0.2~1.8). The calcination temperature in the quartz tube is 300~1000℃. The calcination is carried out in stages: the first stage calcination temperature is 300~500℃, the second stage calcination temperature is 750~1000℃, and the third stage calcination temperature is 450~550℃.

2. The orange phosphor excited by violet light according to claim 1, characterized in that, The emission wavelength of the orange phosphor is 450–800 nm.

3. The violet-excited orange phosphor according to claim 1, characterized in that, The excitation wavelength of the orange phosphor is 200~600nm, which is located in the violet to red light region.

4. The application of a violet-excited orange phosphor as described in any one of claims 1 to 3 in the field of lighting devices, characterized in that, The orange phosphor and the violet chip are used to assemble an LED device.

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