Preparation method of cesium-copper-iodine semiconductor for photoelectric device
By combining hydrothermal and antisolvent processes to prepare cesium copper iodine microcrystalline powder, the problems of low quantum yield and low crystallinity were solved, resulting in high-quality cesium copper iodine powder and improving the luminescence performance and stability of optoelectronic devices.
Patent Information
- Application Number
- CN202511502226.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-21
- Publication Date
- 2026-02-10
AI Technical Summary
The existing cesium copper iodine microcrystalline powder has a low quantum yield and low crystallinity, which affects the photoluminescence effect of optoelectronic devices.
A preparation method combining hydrothermal and antisolvent processes was adopted. The precursor solution was heated and stirred in a reaction vessel, and hypophosphoric acid was added dropwise to a toluene solution. After centrifugation, the solution was dried at low temperature and ground to prepare cesium copper iodine microcrystalline powder with high quantum yield and high crystallinity.
A cesium copper iodine microcrystalline powder with high quantum yield and high stability was achieved, which improved the luminescence performance and stability of optoelectronic devices and avoided the need for high-temperature inert gas protection.
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Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the field of semiconductor halide perovskite light-emitting, in particular to a preparation method of cesium copper iodide semiconductor for optoelectronic devices. BACKGROUND
[0002] Halide perovskite is considered as a promising optoelectronic semiconductor material due to its high quantum yield, tunable emission wavelength, high carrier mobility, etc., and is widely used in solar cells, scintillators, light-emitting diodes, flexible electronics, etc. The general formula of metal halide perovskite is ABX3, where A is a monovalent cation, B is a divalent cation, and X is a halide anion. In recent years, organic-inorganic hybrid halide perovskite has developed rapidly due to its excellent optoelectronic properties, but the poor stability of organic-inorganic hybrid halide perovskite hinders its application. All-inorganic metal halide perovskite has good stability, among which lead-based halide perovskite has developed rapidly due to its excellent optoelectronic properties, but the toxicity of lead still faces great challenges, so all-inorganic lead-free perovskite has attracted widespread attention, reducing toxicity while retaining the excellent optoelectronic properties of halide perovskite.
[0003] Cesium copper iodide belongs to the pnma space group of orthorhombic phase, and Cu has two spatial environments, which are tetrahedral structure of four coordination and triangular structure of three coordination, represented as . Among them, is in a free state and separates . Cesium copper iodide is an excellent non-lead perovskite derivative material, which can emit blue light under the excitation of ultraviolet light. Its luminescence is derived from STE emission caused by lattice polyhedral distortion, and it has the characteristics of wide spectrum, large exciton binding energy, large Stokes shift, long lifetime, etc., and has excellent luminescent properties and stability. Based on these properties, the person skilled in the art applies cesium copper iodide to the fields of LED, ultraviolet photodetection, scintillator, etc.
[0004] High quantum yield of cesium copper iodide microcrystalline powder is closely related to the final performance of optoelectronic devices. The currently reported synthesis methods of cesium copper iodide microcrystalline powder mainly include mechanical ball milling, anti-solvent method and solid phase sintering method. Mechanical ball milling can avoid the use of solvents and has less environmental pollution, but it needs to be completed under the protection of inert gas, which is relatively harsh, and the synthesized microcrystalline powder is not pure, and part of it has not been fully reacted, so the quantum yield effect is not good. Solid phase sintering method can prepare pure phase and high quantum yield, but the synthesis conditions are still relatively harsh, which requires high temperature and protection of inert gas. The high or low of quantum yield is related to the selection of organic solvent and the type of anti-solvent, but the solvent may cause potential harm to the environment.
[0005] The quantum yield of cesium copper iodide microcrystalline powder directly affects the photoluminescence effect of the photoelectric device, so ensuring sufficient reaction of the precursor during the synthesis of the microcrystalline powder, more complete crystal structure and pure phase of the synthesized crystal are beneficial to improve the efficiency of the photoelectric device. SUMMARY
[0006] The application aims to solve the problems of low quantum yield and low crystallinity of cesium copper iodide microcrystalline powder, and provides a preparation method of cesium copper iodide semiconductor for photoelectric devices.
[0007] To achieve the above-mentioned purpose, the application provides a preparation method of cesium copper iodide semiconductor for photoelectric devices, comprising the following steps: S1. Preparation of cesium copper iodide precursor mixed solution The precursor is placed in a beaker and heated and stirred in an air atmosphere to make the precursor completely dissolved in the organic solvent, and then hypophosphorous acid is added dropwise to obtain a precursor mixed solution; S2. Preparation of cesium copper iodide microcrystalline powder The precursor solution is transferred to a polytetrafluoroethylene-lined reaction kettle, and the reaction kettle is heated and reacted in an oven; The cooled mixed solution is added dropwise to the stirring toluene solution to prepare cesium copper iodide microcrystalline powder; S3. Centrifugation, drying and grinding of cesium copper iodide microcrystalline powder The supernatant and cesium copper iodide microcrystalline powder precipitate are separated by centrifugation to obtain moist cesium copper iodide microcrystalline powder, which is dried in an oven at low temperature, and the dried cesium copper iodide microcrystalline powder is ground to obtain all-inorganic cesium copper iodide crystal powder.
[0008] Further, the precursor in S1 is cesium iodide and copper iodide, and the organic solvent in S1 is N,N-dimethylformamide.
[0009] Further, the stirring speed in S1 is 600 rpm / min, the stirring temperature is 60℃, the stirring time is 3min to 5min, and a preservative film is covered on the beaker during stirring, and the concentration of hypophosphorous acid in S1 is 50%.
[0010] Further, the stirring speed in S2 is 500 rpm / min; before the reaction kettle in S2 is placed in an oven for heating and reaction, the oven needs to be preheated at 60℃ for 1h, and after preheating, the reaction kettle is placed in a 60℃ oven for heating and sufficient reaction for 1h.
[0011] Further, the dropwise addition in S2 is performed using a rubber bulb dropper, and the dropwise addition speed is 1s / drop to 2s / drop.
[0012] Further, the speed of centrifugation in the S3 is 5000 rpm / min, the centrifugation time is 5 min, the temperature of the oven is 40 DEG C, the drying reaction time is 4 h, and the grinding treatment time is 20 min.
[0013] Compared with the prior art, the present application has the following beneficial effects: The present application is a preparation method using a hydrothermal process and an anti-solvent process to prepare cesium copper iodide microcrystalline powder with high quantum yield, high crystallinity and high stability, and improves the conventional anti-solvent preparation process. The addition of hypophosphorous acid as a reducing agent in the preparation process can inhibit the oxidation of the cesium copper iodide, and the synthesis in the reaction kettle can make the reaction of the cesium copper iodide more complete, the crystal structure more complete, and the phase more pure, thereby ensuring high stability and high quantum yield.
[0014] The cesium copper iodide microcrystalline powder obtained by the preparation method of the present application not only solves the problems of poor light-emitting effect and poor stability caused by impure phase of the sample prepared by the conventional anti-solvent process, but also retains the advantages of the conventional anti-solvent process, i.e. BRIEF DESCRIPTION OF DRAWINGS
[0015] Figure 1 X-ray diffraction patterns of the separated, dried and ground cesium copper iodide microcrystalline powder of Example 1, Comparative Example 1 and Comparative Example 2; Figure 2 Partial X-ray diffraction patterns of the separated, dried and ground cesium copper iodide microcrystalline powder of Example 1, Comparative Example 1 and Comparative Example 2; Figure 3 Scanning electron microscope image of the cesium copper iodide microcrystalline powder of Example 1; Figure 4 Elemental mapping of Cs in the cesium copper iodide microcrystalline powder of Example 1; Figure 5 Elemental mapping of Cu in the cesium copper iodide microcrystalline powder of Example 1; Figure 6 Elemental mapping of I in the cesium copper iodide microcrystalline powder of Example 1; Figure 7 Excitation spectrum of the cesium copper iodide microcrystalline powder of Example 1, Comparative Example 1 and Comparative Example 2; Figure 8 Luminescence spectrum of the cesium copper iodide microcrystalline powder of Example 1, Comparative Example 1 and Comparative Example 2; Figure 9 Time stability luminescence intensity comparison chart of the cesium copper iodide microcrystalline powder of Example 1, Comparative Example 1 and Comparative Example 2; Figure 10Temperature stability luminescence intensity comparison chart of cesium copper iodine microcrystalline powder of example 1, comparative example 1, comparative example 2. DETAILED DESCRIPTION
[0016] The application will be further described below in conjunction with the examples. The examples are only used to illustrate the application, and are not intended to limit the application in any way.
[0017] It should be clear that the described examples are only a part of the embodiments of the present application, and not all the embodiments. Based on the examples in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present application.
[0018] The raw materials, chemical reagents used in the present application, etc. are not specifically mentioned, and can be obtained through normal commercial channels. The standard of the chemical reagents is the usual standard for laboratory use.
[0019] Example 1 A method for preparing a cesium copper iodine semiconductor for optoelectronic devices, comprising the following steps: S1. Preparation of cesium copper iodine precursor mixed solution The precursor 0.7788 g of cesium iodide (CsI) and 0.3809 g of copper iodide (CuI) were placed in a 20 mL beaker, heated and stirred (60°C, 600 rpm / min) under air atmosphere for 3 min to 5 min, so that the CsI and CuI were completely dissolved in 5 mL of organic solvent N,N-dimethylformamide (DMF), and then 250 μL of hypophosphorous acid with a concentration of 50% was added dropwise to obtain a precursor mixed solution. A protective film was covered on the surface of the beaker during stirring.
[0020] S2. Preparation of cesium copper iodine microcrystalline powder The precursor solution was transferred to a polytetrafluoroethylene-lined reaction kettle, which was preheated in an oven at 60°C for 1 h, and then the reaction kettle was placed in an oven at 60°C for 1 h to heat and react sufficiently. The cooled mixed solution was added dropwise to a stirring 20 mL toluene solution using a rubber bulb dropper, with a stirring speed of 500 rpm / min and a dropwise speed of 1 s / drop to 2 s / drop, to obtain cesium copper iodine microcrystalline powder.
[0021] S3. Centrifugation, drying and grinding of cesium copper iodine microcrystalline powder The supernatant was separated from the cesium copper iodine microcrystalline powder precipitate by centrifugation (5 min, 5000 rpm / min) to obtain moist cesium copper iodine microcrystalline powder. The moist cesium copper iodine microcrystalline powder was dried at a low temperature in an oven (40°C, 4 h), and the dried cesium copper iodine microcrystalline powder was ground in a mortar for 20 min to obtain all-inorganic cesium copper iodine microcrystalline powder.
[0022] A method for preparing a cesium copper iodine semiconductor for a photoelectric device, comprising the following steps: S1. Preparation of a cesium copper iodine precursor mixed solution The precursors 0.7788 g of CsI and 0.3809 g of Cul were placed in a 20 mL beaker, heated and stirred under an air atmosphere (60°C, 600 rpm / min) for 60 min, so that the CsI and Cul were completely dissolved in 5 mL of an organic solvent DMF, and 250 μL of hypophosphorous acid with a concentration of 50% was added dropwise to obtain a precursor mixed solution, and a protective film was covered on the surface of the beaker during stirring.
[0023] S2. Preparation of a cesium copper iodine microcrystalline powder After the precursor mixed solution was cooled, the mixed solution of the precursor solution was added dropwise into a 20 mL toluene solution being stirred using a rubber bulb dropper, the stirring speed was 500 rpm / min, and the dropping speed was 1 s / drop to 2 s / drop, to prepare a cesium copper iodine microcrystalline powder.
[0024] S3. Centrifugal, drying and grinding treatment of the cesium copper iodine microcrystalline powder The supernatant was separated from the cesium copper iodine microcrystalline powder precipitate by centrifugal process (5 min, 5000 rpm / min) to obtain a moist cesium copper iodine microcrystalline powder, which was placed in an oven for low-temperature drying (40°C, 4 h), and the dried cesium copper iodine microcrystalline powder was ground in a mortar for 20 min to obtain an all-inorganic cesium copper iodine microcrystalline powder.
[0025] A method for preparing a cesium copper iodine semiconductor for a photoelectric device, comprising the following steps: S1. Preparation of a cesium copper iodine precursor mixed solution The precursors 0.7788 g of CsI and 0.3809 g of Cul were placed in a 20 mL beaker, heated and stirred under an air atmosphere (60°C, 600 rpm / min) for 60 min, so that the CsI and Cul were completely dissolved in 5 mL of an organic solvent DMF, and 250 μL of hypophosphorous acid with a concentration of 50% was added dropwise to obtain a precursor mixed solution, and a protective film was covered on the surface of the beaker during stirring.
[0026] S2. Preparation of a cesium copper iodine microcrystalline powder After the precursor mixed solution was cooled, the mixed solution of the precursor solution was added dropwise into a 20 mL toluene solution being stirred using a rubber bulb dropper, the stirring speed was 500 rpm / min, and the dropping speed was 1 s / drop to 2 s / drop, to prepare a cesium copper iodine microcrystalline powder.
[0027] S3. Centrifugal, drying and grinding treatment of the cesium copper iodine microcrystalline powder The supernatant was separated from the cesium copper iodine microcrystalline powder precipitate by centrifugation process (5 min, 5000 rpm / min) to obtain a wet cesium copper iodine microcrystalline powder, and the wet cesium copper iodine microcrystalline powder was placed in an oven for low-temperature drying (40℃, 4 h), and the dried cesium copper iodine microcrystalline powder was ground in a mortar for 20 min to obtain an all-inorganic cesium copper iodine microcrystalline powder.
[0028] The cesium copper iodine microcrystalline powders prepared by the examples 1, comparative example 1 and comparative example 2 adopted different processes. The example 1 used a preparation method combining anti-solvent process and hydrothermal process, the comparative example 1 used a traditional anti-solvent process method, and the reaction process was completely carried out in a beaker without fully reacting in a reaction kettle. The reaction process of the comparative example 2 was also completely carried out in a beaker, and no hypophosphorous acid was added.
[0029] Figure 1 The X-ray diffraction (XRD) patterns of the three kinds of cesium copper iodine (CsI) microcrystalline powders prepared by the example 1, comparative example 1 and comparative example 2 are shown in the following table. The XRD patterns of the cesium copper iodine microcrystalline powders prepared by the example 1, comparative example 1 and comparative example 2 were observed, and the main diffraction peaks of (221), (123), (104), (311) and (040) were well matched with the standard card (PDF #01-072-9850) of cesium copper iodine, which proved that the cesium copper iodine microcrystalline powders were successfully prepared by the example 1, comparative example 1 and comparative example 2, and the three kinds of cesium copper iodine microcrystalline powders all had complete crystal structure and strong diffraction peaks.
[0030] Figure 2 The partial XRD patterns of the cesium copper iodine microcrystalline powders of the example 1, comparative example 1 and comparative example 2 are shown in the following table. The partial XRD phase analysis of the cesium copper iodine microcrystalline powders prepared by the example 1, comparative example 1 and comparative example 2 was carried out, and compared with the CsI standard card (PDF #04-006-2282). The cesium copper iodine microcrystalline powder prepared by the comparative example 1 had a small amount of CsI raw material phase at diffraction angles of 39.34° and 48.76°, while the cesium copper iodine microcrystalline powders prepared by the example 1 and comparative example 2 had CsI raw material phase. It was proved that the preparation method of the cesium copper iodine microcrystalline powder of the comparative example 1 could not make the precursor completely react, resulting in the existence of CsI residual phase. The main reason for the generation of CsI residual phase is that the complexation of hypophosphorous acid inhibits the reaction of CsI (coordination of The complexation slows down the reaction rate of , which hinders the complete conversion of CsI into the target product. In the comparative example 2, no complex was generated, which is because and The reaction activity is high, and can quickly generate the target product with CuI. Therefore, there is no CsI residual phase in the XRD pattern of Comparative Example 2. The preparation method of Example 1 is to perform the reaction by high pressure, which can inhibit the generation of complex, and release free participate in the reaction, and can make CsI and CuI fully react, and therefore, no CsI phase is generated in the XRD pattern of Example 1.
[0031] Figure 3 The scanning electron microscope (SEM) pattern and element surface distribution (EDS) pattern of the cesium copper iodide microcrystal powder prepared in Example 1 are shown. The results show that the particle size of the cesium copper iodide microcrystal powder prepared in Example 1 is about 5 μm, and the crystal structure is complete and clear without obvious defects. At the same time, Figure 4 Figure 5 and Figure 6 The EDS patterns of Cs, Cu and I are also shown, and the results show that Cs, Cu and I in the cesium copper iodide microcrystal powder are uniformly distributed.
[0032] Figure 7 The excitation spectra of the cesium copper iodide microcrystal powder of Example 1, Comparative Example 1 and Comparative Example 2 under different wavelengths are shown. The optimal excitation wavelength of the three kinds of cesium copper iodide microcrystal powder prepared in Example 1, Comparative Example 1 and Comparative Example 2 is 305 nm, and the excitation intensity from top to bottom is Example 1> Comparative Example 1> Comparative Example 2, which can indicate that the cesium copper iodide microcrystal powder prepared in Example 1 absorbs the most excitation light under the excitation wavelength of 305 nm.
[0033] Figure 8 The luminescence spectra of the cesium copper iodide microcrystal powder of Example 1, Comparative Example 1 and Comparative Example 2 are shown. The luminescence peak of the cesium copper iodide prepared in Example 1, Comparative Example 1 and Comparative Example 2 appears at 445 nm, and the luminescence intensity from strong to weak is Example 1> Comparative Example 1> Comparative Example 2, which can indicate that under the same excitation condition, the luminescence intensity of the cesium copper iodide microcrystal powder prepared in Example 1 is the strongest.
[0034] Figure 9 The time stability luminescence intensity comparison chart of the cesium copper iodide microcrystal powder prepared in Example 1, Comparative Example 1 and Comparative Example 2 is shown. With the increase of time, the luminescence intensity of the cesium copper iodide microcrystal powder prepared in Example 1, Comparative Example 1 and Comparative Example 2 all appears a certain degree of reduction, and when the luminescence intensity test is performed again after being placed for 56 days, it is found that the luminescence intensity of the cesium copper iodide microcrystal powder prepared in Example 1 is still much higher than that of the cesium copper iodide microcrystal powder prepared in Comparative Example 1 and Comparative Example 2.
[0035] Figure 10 The temperature stability luminescence intensity comparison chart of cesium copper iodine microcrystal powder of example 1, comparative example 1 and comparative example 2. With the increase of temperature, the luminescence intensity of cesium copper iodine microcrystal powder prepared by example 1, comparative example 1 and comparative example 2 has a certain amplitude of decline, at 180℃, the decline amplitude of luminescence intensity of cesium copper iodine microcrystal powder prepared by example 1 is larger, but the luminescence intensity of cesium copper iodine microcrystal powder prepared by example 1 is still higher than that of comparative example 1 and comparative example 2.
[0036] The quantum yield (PLQY) of cesium copper iodine microcrystal powder prepared by example 1, comparative example 1 and comparative example 2 is calculated as shown in table 1: Table 1, PLQY (%) of cesium copper iodine microcrystal powder prepared by example 1, comparative example 1 and comparative example 2 .
[0037] From table 1, it can be seen that the cesium copper iodine microcrystal powder prepared by the method of combining anti-solvent process and hydrothermal process of example 1 has high PLQY (%), and the process of hydrothermal method is to make the reaction more sufficient and the crystal structure more complete, thereby improving the luminescence performance. The cesium copper iodine microcrystal powder prepared by comparative example 1 also has high PLQY (%), according to the XRD chart, it can be seen that there is a small amount of CsI raw material phase at the diffraction angle of 39.34° and 48.76° in the cesium copper iodine prepared by comparative example 1, which proves that the preparation method of cesium copper iodine microcrystal powder in comparative example 1 cannot make the precursor completely react, resulting in the existence of residual phase of CsI, so that the phase structure is not pure enough, resulting in the material in the luminescence performance is worse than example 1. In the preparation method of cesium copper iodine microcrystal powder in comparative example 2, no hypophosphorous acid is added, so that the is oxidized, resulting in poor luminescence performance of cesium copper iodine microcrystal powder.
[0038] Of course, the above description is not a limitation of the present application, and the present application is not limited to the above examples, and the changes, modifications, additions or substitutions made by the person skilled in the art within the essential scope of the present application should also belong to the protection scope of the present application.
Claims
1. A method for preparing a cesium copper iodine semiconductor for optoelectronic devices, characterized in that, Includes the following steps: S1. Preparation of a mixed solution of cesium copper iodine precursors The precursor was placed in a beaker and heated and stirred in air to completely dissolve the precursor in the organic solvent. Then hypophosphoric acid was added dropwise to obtain a mixed solution of the precursor. S2. Preparation of cesium copper iodine microcrystalline powder The precursor solution was transferred into a polytetrafluoroethylene reactor liner, and the reactor was placed in an oven for heating and reaction. The cooled mixed solution was added dropwise to a toluene solution under stirring to prepare cesium copper iodine microcrystalline powder. S3. Cesium copper iodine microcrystalline powder is centrifuged, dried, and ground. The supernatant was separated from the cesium copper iodine microcrystalline powder by centrifugation to obtain moist cesium copper iodine microcrystalline powder. The moist cesium copper iodine microcrystalline powder was placed in an oven and dried at low temperature. The dried cesium copper iodine microcrystalline powder was then ground to obtain inorganic cesium copper iodine crystal powder.
2. The method for preparing a cesium copper iodine semiconductor for optoelectronic devices according to claim 1, characterized in that, The precursors in S1 are cesium iodide and copper iodide, and the organic solvent in S1 is N,N-dimethylformamide.
3. The method for preparing a cesium copper iodine semiconductor for optoelectronic devices according to claim 1, characterized in that, The stirring speed in S1 is 600 rpm / min, the stirring temperature is 60℃, and the stirring time is 3 to 5 minutes. During stirring, the beaker is covered with plastic wrap. The concentration of hypophosphoric acid in S1 is 50%.
4. The method for preparing a cesium copper iodine semiconductor for optoelectronic devices according to claim 1, characterized in that, The stirring speed in S2 is 500 rpm / min; before the reaction vessel in S2 is placed in the oven for heating, the oven needs to be preheated to 60°C for 1 hour, and after preheating, the reaction vessel is placed in the 60°C oven for heating to fully react for 1 hour.
5. The method for preparing a cesium copper iodine semiconductor for optoelectronic devices according to claim 1, characterized in that, The dripping in S2 is performed using a dropper with a rubber tip, at a dripping rate of 1 to 2 drops per second.
6. The method for preparing a cesium copper iodine semiconductor for optoelectronic devices according to claim 1, characterized in that, In S3, the centrifugation speed is 5000 rpm / min, the centrifugation time is 5 min, the oven temperature is 40℃, the drying reaction time is 4 h, and the grinding treatment time is 20 min.