A three-dimensional cadmium-based perovskite crystal with near-infrared fluorescence thermal enhancement and a preparation method thereof

Abstract

A three-dimensional cadmium-based perovskite crystal with near-infrared fluorescence thermal enhancement and a preparation method thereof, which relates to a near-infrared fluorescent cadmium-based perovskite crystal and a preparation method thereof, and aims to solve the technical problems of high synthesis cost and poor thermal stability of existing near-infrared fluorescent powders. The chemical expression of the three-dimensional cadmium-based perovskite crystal with near-infrared fluorescence thermal enhancement of the present invention is CsCdCl 3 :xSb 3+ ,yYb 3+ , where 0<x≤0.3, 0<y≤0.3. It is obtained by mixing cesium source, cadmium source, antimony source and ytterbium source and calcining them. The near-infrared luminescence intensity of the crystal at 110°C is 1.69 times that at room temperature. It can perfectly adapt to the higher operating temperature of the near-infrared light source and can be used in biomedicine, food inspection, optical instruments, night vision technology and plant growth.

Description

Technical Field

[0001] The invention relates to a near-infrared fluorescent cadmium-based perovskite crystal and a preparation method thereof, and belongs to the technical field of luminescent materials. Background Art

[0002] Near-infrared light (700-2500nm) is an important part of the electromagnetic spectrum, with the characteristics of being beyond human eye perception, broadband absorption of corresponding molecular vibrations, and penetrating deep into biological tissues. Therefore, near-infrared light sources are widely used in biomedicine, food inspection, optical instruments, night vision technology, and plant growth.

[0003] As the core component of near-infrared light sources, near-infrared phosphors have many advantages, such as high quantum efficiency, excellent luminescence performance, a wide excitation spectrum range, and tunable emission wavelength. However, most traditional near-infrared phosphors are oxides, and the synthesis of these oxides requires a high synthesis temperature, which greatly increases the cost of synthesis and the safety risks in the production process. In contrast, various halide perovskite materials have excellent optical properties and are easy to synthesize, and can be used as new near-infrared phosphors.

[0004] Another existing problem is that the operating temperature of near-infrared light sources is relatively high, and near-infrared phosphors are susceptible to thermal quenching at higher temperatures, which reduces the luminous intensity and thus affects the stability and reliability of the entire device. Therefore, higher thermal stability has become a rigid requirement for near-infrared phosphors. Summary of the invention

[0005] The present invention aims to solve the technical problems of high synthesis cost and poor thermal stability of existing near-infrared phosphors, and to provide a three-dimensional cadmium-based perovskite crystal with near-infrared fluorescence thermal enhancement and a preparation method thereof.

[0006] The chemical expression of the three-dimensional cadmium-based perovskite crystal with near-infrared fluorescence thermal enhancement of the present invention is CsCdCl3:xSb 3 + ,yYb 3+ , where 0<x≤0.3, 0<y≤0.3.

[0007] The method for preparing the three-dimensional cadmium-based perovskite crystal with near-infrared fluorescence thermal enhancement is carried out according to the following steps:

[0008] 1. According to the cadmium-based perovskite crystal CsCdCl3:xSb 3+ ,yYb 3+ , accurately weigh the cesium source, cadmium source, antimony source and ytterbium source in a stoichiometric ratio of 0<x≤0.3, 0<y≤0.3;

[0009] 2. Add the cesium source, cadmium source, antimony source and ytterbium source weighed in step 1 into an agate mortar, add an appropriate amount of deionized water to grind the mixture in the mortar, and then transfer the mixture to an oven for drying to obtain a raw material powder.

[0010] 3. Transfer the raw material powder into a corundum crucible, place the corundum crucible in a muffle furnace, heat it to 350-360°C at a heating rate of 5-10°C / min, and calcine it for 2-3 hours. Then cool it to room temperature at a cooling rate of 5-10°C / min to obtain three-dimensional cadmium-based perovskite crystals with near-infrared fluorescence thermal enhancement.

[0011] Furthermore, the cesium source in step 1 is cesium chloride.

[0012] Furthermore, the cadmium source described in step 1 is cadmium chloride.

[0013] Furthermore, the antimony source in step 1 is antimony chloride, antimony acetate or a combination of both.

[0014] Furthermore, the ytterbium source in step 1 is one or a combination of ytterbium chloride and ytterbium acetate.

[0015] Furthermore, the amount of deionized water added in step 2 is based on the ratio of the amount of the cesium source to the volume of deionized water of 1 mmol: (6-8) mL. Water is added as a solvent to make the grinding more uniform.

[0016] Furthermore, the grinding time in step 2 is ≥ 30 min.

[0017] Furthermore, the drying in step 2 is carried out at an oven temperature of 70 to 100° C. for 1 to 2 hours.

[0018] The near-infrared fluorescence thermally enhanced cadmium-based perovskite crystal of the present invention uses CsCdCl3 as a matrix material, and Yb and Sb are doped in the matrix, so that the effect of thermally enhanced near-infrared emission can be achieved through efficient thermally enhanced energy transfer between Sb-Yb: the crystal emits near-infrared light with a peak wavelength of 980nm under ultraviolet excitation, and as the temperature rises, the energy stored in the trap energy levels in the lattice will gradually be transferred to the Yb emission center through the Sb emission center, thereby enhancing the near-infrared characteristic emission of Yb at 980nm. The near-infrared luminescence intensity of the crystal at 110°C is 1.69 times that at room temperature, which can perfectly adapt to the higher operating temperature of the near-infrared light source.

[0019] The preparation method of the three-dimensional cadmium-based perovskite crystal with near-infrared fluorescence thermal enhancement of the present invention is simple, pollution-free, has no wastewater and waste gas emissions, is non-radioactive, does not require inert gas protection, does not cause harm to the environment, is simple to operate, and is suitable for large-scale industrial production. The three-dimensional cadmium-based perovskite crystal with near-infrared fluorescence thermal enhancement of the present invention can be used in the fields of biomedicine, food inspection, optical instruments, night vision technology, and plant growth. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a scanning electron microscope image of the three-dimensional cadmium-based perovskite crystal with near-infrared fluorescence thermal enhancement prepared in Example 1.

[0021] Figure 2 This is the X-ray diffraction spectrum of the three-dimensional cadmium-based perovskite crystal with near-infrared fluorescence thermal enhancement prepared in Example 1-2.

[0022] Figure 3 CsCdCl3:0.1Sb prepared in Comparative Example 2 3+ Excitation spectra of the crystal and the CsCdCl3 crystal obtained in Comparative Example 3 at 580nm.

[0023] Figure 4 It is the emission spectra of the crystals prepared in Example 1-2 and Comparative Example 1-2 in the visible band and the near-infrared band under 254nm excitation.

[0024] Figure 5 CsCdCl3:0.1Sb prepared in Example 1 3+ ,0.15Yb 3+ Comparison of emission spectra of perovskite crystals in the near-infrared band under 254nm excitation at different temperatures. DETAILED DESCRIPTION

[0025] The technical solution of the present invention is described in detail below with reference to the accompanying drawings and examples, but the present invention is not limited to the scope of the described embodiments.

[0026] Example 1: The preparation method of the three-dimensional cadmium-based perovskite crystal with near-infrared fluorescence thermal enhancement of this example is carried out according to the following steps:

[0027] 1. According to the chemical formula CsCdCl3:0.1Sb 3+ ,0.15Yb 3+ Accurately weigh 0.1683 g of cesium chloride, 0.1833 g of cadmium chloride, 0.0298 g of antimony acetate, and 0.0193 g of ytterbium chloride;

[0028] 2. Add cesium chloride, cadmium chloride, antimony acetate and ytterbium chloride into an agate mortar, add 6 mL of deionized water as a solvent, grind the mixture thoroughly for 30 min, transfer the ground mixture to an oven at 70 ° C and dry it for 1 h to obtain a raw material powder;

[0029] 3. The raw material powder was transferred into a corundum crucible, and the corundum crucible was placed in a muffle furnace, heated to 350°C at a heating rate of 5°C / min and calcined for 2h, and then cooled to room temperature at a cooling rate of 5°C / min to obtain a three-dimensional cadmium-based perovskite crystal CsCdCl3:0.1Sb with near-infrared fluorescence thermal enhancement. 3+ ,0.15Yb 3+ .

[0030] Example 2: The preparation method of the cadmium-based perovskite near-infrared phosphor of this example is carried out according to the following steps:

[0031] Step 1: According to the chemical formula CsCdCl3:0.3Sb 3+ ,0.3Yb 3+ , accurately weigh 0.1683 g of cesium chloride, 0.1833 g of cadmium chloride, 0.0894 g of antimony acetate and 0.1743 g of ytterbium chloride.

[0032] Step 2: Add cesium chloride, cadmium chloride, antimony acetate and ytterbium chloride into an agate mortar, add 6 mL of deionized water as a solvent, and grind the resulting mixture thoroughly for 30 minutes.

[0033] Step 3: Transfer the ground mixture to an oven at 70°C and dry for 1 hour to obtain raw material powder.

[0034] Step 4: Transfer the raw material powder into a corundum crucible, place the corundum crucible in a muffle furnace, heat it to 350°C at a heating rate of 5°C / min, calcine for 2h, and cool it to room temperature at a cooling rate of 5°C / min.

[0035] Comparative Example 1: The difference between this comparative example and Example 1 is that antimony acetate is omitted in step 1, and the other steps and parameters are the same as those in Example 1. The obtained material is CsCdCl3:0.15Yb 3+ .

[0036] Comparative Example 2: The difference between this comparative example and Example 1 is that ytterbium chloride is omitted in step 1, and the other steps and parameters are the same as those in Example 1. The obtained material is CsCdCl3:0.1Sb 3+ .

[0037] Comparative Example 3: This comparative example is different from Example 1 in that ytterbium chloride and antimony acetate are omitted in step 1, and the other steps and parameters are the same as those in Example 1, and the obtained material is CsCdCl3.

[0038] Figure 1 This is a scanning electron microscope image of the three-dimensional cadmium-based perovskite crystal with near-infrared fluorescence thermal enhancement obtained in Example 1. From the scanning electron microscope image, it can be seen that the obtained three-dimensional perovskite crystal has a hexagonal phase structure and a size of 150 μm.

[0039] Figure 2 is the X-ray diffraction spectrum of the three-dimensional cadmium-based perovskite crystal with near-infrared fluorescence thermal enhancement obtained in Example 1-2. Figure 2 It can be seen that the diffraction peak of the three-dimensional cadmium-based perovskite crystal with near-infrared fluorescence thermal enhancement obtained in Example 1 corresponds to the diffraction peak of the PDF standard card of CsCdCl3, indicating that the crystal structure of CsCdCl3 has not changed after doping, and the obtained crystal is pure phase.

[0040] Figure 3 The CsCdCl3:0.1Sb prepared in Example 2 3+ The excitation spectra of the CsCdCl3 crystal obtained in the comparative example 3 at 580nm. Figure 3 It can be seen that when doped with Sb 3+ In the case of an additional excitation peak, this means that Sb 3+ The introduction of adds an energy transfer process from Sb to Yb sensitization to the material, further increasing the material's absorption of ultraviolet light and energy transfer.

[0041] Figure 4 The emission spectra of the crystals prepared in Example 1-2 and Comparative Example 1-2 in the visible band and near infrared band under 254nm excitation are shown in FIG. Figure 4 It can be seen that without Yb 3+ When the crystal does not have Yb at 980nm 3+ Characteristic near-infrared emission of Yb alone 3+ When Yb is introduced at 980nm 3+ The characteristic near-infrared emission of Yb 3+ With Sb 3+ After co-doping, Yb 3+ With Sb 3+ To Yb 3+ The efficient energy transfer of Yb 3+ The characteristic near-infrared emission intensity of Sb 3+ The emission wavelength is 580 nm. 3+ Too high a concentration of Yb will also be affected by concentration quenching and quench its luminescence. 3+ As the concentration of Yb increases, 3+ The luminescence will also be quenched.

[0042] Figure 5The three-dimensional cadmium-based perovskite crystal CsCdCl3:0.1Sb with near-infrared fluorescence thermal enhancement prepared in Example 1 3 + ,0.15Yb 3+ Comparison of emission spectra in the near-infrared band under 254nm excitation at different temperatures. Figure 5 It can be seen that as the temperature gradually increases, the wavelength at 980nm belongs to Yb 3+ The characteristic emission intensity gradually increases, showing the characteristics of thermal enhancement. At 110°C, its luminescence intensity is 1.69 times that at room temperature.

Claims

1. A three-dimensional cadmium-based perovskite crystal with near-infrared fluorescence thermal enhancement, characterized in that: The chemical formula of the crystal is CsCdCl3:xSb 3+ ,yYb 3+ , where 0<x≤0.3, 0<y≤0.

3.

2. A method for preparing a three-dimensional cadmium-based perovskite crystal with near-infrared fluorescence thermal enhancement according to claim 1, characterized in that: The method proceeds as follows:

1. According to the cadmium-based perovskite crystal CsCdCl3:xSb 3+ ,yYb 3+ , accurately weigh the cesium source, cadmium source, antimony source and ytterbium source in a stoichiometric ratio of 0<x≤0.3, 0<y≤0.3; 2. Add the cesium source, cadmium source, antimony source and ytterbium source weighed in step 1 into an agate mortar, add an appropriate amount of deionized water to grind the mixture in the mortar, and then transfer the mixture to an oven for drying to obtain a raw material powder; 3. Transfer the raw material powder into a corundum crucible, place the corundum crucible in a muffle furnace, heat it to 350-360°C at a heating rate of 5-10°C / min, and calcine it for 2-3 hours. Then cool it to room temperature at a cooling rate of 5-10°C / min to obtain three-dimensional cadmium-based perovskite crystals with near-infrared fluorescence thermal enhancement.

3. The method for preparing a three-dimensional cadmium-based perovskite crystal with near-infrared fluorescence thermal enhancement according to claim 2, characterized in that: The cesium source described in step 1 is cesium chloride.

4. The method for preparing a three-dimensional cadmium-based perovskite crystal with near-infrared fluorescence thermal enhancement according to claim 2 or 3, characterized in that: The cadmium source described in step 1 is cadmium chloride.

5. The method for preparing a three-dimensional cadmium-based perovskite crystal with near-infrared fluorescence thermal enhancement according to claim 2 or 3, characterized in that: The antimony source in step 1 is antimony chloride, antimony acetate or a combination of both.

6. The method for preparing a three-dimensional cadmium-based perovskite crystal with near-infrared fluorescence thermal enhancement according to claim 2 or 3, characterized in that: The ytterbium source in step 1 is one or a combination of ytterbium chloride and ytterbium acetate.

7. The method for preparing a three-dimensional cadmium-based perovskite crystal with near-infrared fluorescence thermal enhancement according to claim 2 or 3, characterized in that: The amount of deionized water added in step 2 is based on the ratio of the amount of the cesium source substance to the volume of deionized water of 1 mmol: (6-8) mL.

8. The method for preparing a three-dimensional cadmium-based perovskite crystal with near-infrared fluorescence thermal enhancement according to claim 2 or 3, characterized in that: The grinding time of the grinding in step 2 is ≥ 30 min.

9. The method for preparing a three-dimensional cadmium-based perovskite crystal with near-infrared fluorescence thermal enhancement according to claim 2 or 3, characterized in that: The drying described in step 2 is carried out in an oven at a temperature of 70 to 100° C. for 1 to 2 hours.

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