Method for preparing highly stable perovskite crystal by spontaneous reaction at room temperature

Abstract

Disclosed in the present invention is a method for preparing a highly stable perovskite crystal by a spontaneous reaction at room temperature. The method comprises: mixing a halide salt AX, a metal halide BX2 and a catalyst amino salt in a certain ratio, and then adding a carbonate solvent to the mixed powder. By means of a spontaneous chemical reaction between the carbonate and the catalyst amino salt, a chemical reaction between the halide salt AX and the metal halide BX2 is induced at room temperature, thereby obtaining a perovskite crystal having high quality and high stability. In the present invention, high-quality perovskite crystal can be obtained at room temperature. The present invention breaks through the limitation of conditions such as long-term high-temperature and acidic conditions required for preparing the perovskite crystal, and is convenient for large-scale industrialization. The perovskite crystal powder having high quality and ultra-high stability obtained by means of the method of the present invention can be widely used in photoelectric fields such as batteries, light emission and detectors.

Description

A method for preparing highly stable perovskite crystals via spontaneous reaction at room temperature Technical Field

[0001] This invention relates to the fields of semiconductor optoelectronic materials and energy materials, specifically to a method for preparing highly stable perovskite crystals via a spontaneous reaction at room temperature. Background Technology

[0002] Since 2009, halide perovskite materials have rapidly become a research hotspot in the optoelectronic field due to their unique physical properties, such as long carrier diffusion lengths, high light absorption efficiency, and band gaps that can be tuned through chemical composition. They have shown great application potential, particularly in solar cells, light-emitting diodes (LEDs), photodetectors, and lasers. These properties make halide perovskites a strong candidate to replace traditional silicon-based semiconductor materials, especially in the pursuit of high-efficiency, low-cost, and easily fabricated optoelectronic devices.

[0003] However, despite the remarkable performance of halide perovskite materials under laboratory conditions, their stability in practical applications has become a major bottleneck restricting their industrialization. The stability issues of perovskite materials are mainly manifested in their susceptibility to phase transitions, decomposition, or ion migration under environmental factors such as humidity, temperature, and light, leading to rapid performance degradation of devices. These problems not only affect the long-term stability of devices but also increase production costs and maintenance difficulties, limiting their widespread commercial application.

[0004] To improve the stability of halide perovskites, researchers have developed various strategies aimed at addressing both the internal structure and external environment of the material. These strategies, including reducing defects, suppressing ion migration, and optimizing interfacial contacts, effectively enhance the stability of perovskite materials. The following is a detailed explanation of these strategies and their core principles:

[0005] Additive method: By adding appropriate additives, such as Lewis acids, Lewis bases, small organic molecules, or polymers, to the precursor solution, defects at perovskite grain boundaries and surfaces can be effectively passivated, reducing non-radiative recombination and thus improving the photoelectric conversion efficiency and stability of the device. The mechanism of action of additives is usually through binding with uncoordinated ions or defect sites in the perovskite to form stable chemical bonds, thereby inhibiting ion migration and water molecule penetration.

[0006] Dimensional engineering: By adjusting the dimensionality of perovskite materials, such as transitioning from a three-dimensional structure to a two-dimensional or quasi-two-dimensional structure, their physical and chemical properties, especially stability and optoelectronic performance, can be significantly affected. Low-dimensional perovskite materials typically exhibit higher stability and more tunable optoelectronic properties due to quantum confinement effects and enhanced surface interactions. Furthermore, two-dimensional perovskites can effectively suppress ion migration and improve the moisture resistance of devices.

[0007] Interface modification: Introducing buffer layers or interface modification layers, such as metal oxides, polymers, or self-assembled monolayers (SAMs), between the perovskite layer and other functional layers can effectively improve charge transport at the interface, reduce interfacial recombination, and simultaneously block the penetration of moisture and oxygen, thereby improving the overall stability of the device. The selection and design of the interface modification layer need to be optimized according to the specific application scenario and device structure to achieve the best balance between stability and performance.

[0008] Improving precursor quality: Given the complex chemical crystallization process of halide perovskites and its susceptibility to defects, increasing the purity of precursor materials is the fundamental way to reduce defect formation and improve stability. High-purity precursor materials not only reduce the introduction of impurities but also ensure precise control of the chemical reaction, avoiding the formation of iodine impurities and changes in solution pH caused by stoichiometric imbalances, thereby significantly improving the quality and stability of perovskite films. This requires strict control and management from raw material selection and synthesis processes to storage conditions.

[0009] In conclusion, although halide perovskite materials have shown great application potential in the optoelectronic field, their stability remains a key challenge for achieving large-scale industrialization.

[0010] Summary of the Invention

[0011] To address the shortcomings of existing technologies, this invention provides a method for preparing highly stable perovskite crystals through a spontaneous reaction at room temperature. By utilizing the spontaneous chemical reaction between a catalyst amine salt and a solvent, various perovskite raw materials spontaneously react to form perovskite crystals, ultimately obtaining high-quality, ultra-high-stability perovskite microcrystalline powder for the preparation of perovskite optoelectronic devices.

[0012] Specifically, the purpose of this invention is to provide a novel and energy-free room-temperature method for preparing high-quality perovskite crystals. This method involves mixing a halide salt AX, a metal halide BX2, and a catalyst amino salt in a certain proportion, followed by adding a carbonate solvent to the mixed powder. The spontaneous chemical reaction between the carbonate and the catalyst amino salt induces a chemical reaction between the halide salt AX and the metal halide BX2 at room temperature, ultimately yielding high-quality, highly stable perovskite crystals.

[0013] This invention provides a method for preparing highly stable perovskite crystals via spontaneous reaction at room temperature, comprising the following steps:

[0014] S1, mix halide salt AX, halide metal BX2 and catalyst amino salt to obtain mixed powder 1.

[0015] In this context, A in halide salt AX represents inorganic and / or organic cations; B in halide metal BX2 represents divalent metal ions; amino salts in catalysts include amino hydrochloride salts, such as MAX and DMAX (MA is methylamine, DMA is dimethylamine); and X represents halide anions.

[0016] S2, add solvent to mixed powder 1 to obtain solution 2.

[0017] The solvent is a carbonate solvent in which one of the carbon atoms simultaneously includes a C=O and two CO single bonds. The C=O and CO first react with PbI2 simultaneously, and then react with the amino functional group of the catalyst to promote the formation of perovskite crystals.

[0018] S3, under room temperature conditions, stir solution 2 to react and obtain a mixture 3 containing perovskite crystal powder; after standing until the powder is completely precipitated, remove the supernatant to obtain black powder 4; wash black powder 4 with a solvent that is insoluble in perovskite to obtain black perovskite powder 5; vacuum dry the obtained black perovskite powder 5 to obtain microcrystalline perovskite powder 6, which is the highly stable perovskite crystal.

[0019] Specifically, in step S1, in order to synthesize perovskite crystals, A in the halide salt AX can be selected as MA. + FA + Cs + and Rb + At least one of them;

[0020] In metal halide BX2, B can be Pb. 2+ and Sn 2+ At least one of them;

[0021] X is I - ,Br - and Cl - At least one of them.

[0022] The catalyst ammonium salt is at least one of dimethylamine hydroiodide (DMAI), methylamine iodide (MACl), and methylamine chloride (MAI), and its purpose is to catalyze the reaction with the solvent to induce the formation of perovskite crystals.

[0023] Preferably, the molar ratio of halide salt AX, halide metal BX2 and auxiliary amino salt is 1:1:x (x≥0.2).

[0024] Preferably, in step S2, the carbonate solvent that simultaneously includes one C=O and two CO single bonds on the carbon is at least one of ethylene carbonate, diethyl carbonate, propylene carbonate, dimethyl carbonate, and methyl ethyl carbonate. In these solvents, C=O and CO first react simultaneously with PbI2, and then react with the amino functional group.

[0025] Preferably, in step S2, the amount of solvent added is such that the molar concentration of both the halide salt AX and the halide metal BX2 is greater than 0.5 mol / L.

[0026] In some embodiments of the present invention, in step S3, the method for removing the supernatant is filtration or rotary evaporation. The mixture 3 is allowed to stand for 0.5 to 2 hours. The solvent for insoluble perovskite is at least one of diethyl ether and acetonitrile.

[0027] In step S3, the final black cleaning powder is vacuum dried for 1 to 24 hours.

[0028] The present invention also provides highly stable perovskite crystals prepared by the method.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. This invention simply adds carbonate solvents directly to perovskite raw materials. By utilizing the catalytic reaction between carbonate solvents and catalysts, a large quantity of microcrystalline powder can be obtained in a short time. Moreover, the obtained microcrystalline powder has good stability. The preparation method provided by this invention is simple and easy to control, and is convenient for industrial production.

[0031] 2. This invention allows for the direct addition of carbonate solvents to perovskite raw materials, resulting in high-quality perovskite microcrystals at room temperature. This invention overcomes the current limitations of requiring prolonged high temperatures and acidic conditions for the preparation of perovskite microcrystals, facilitating large-scale industrialization.

[0032] 3. The high-quality perovskite crystal powder with ultra-high stability obtained by the method of the present invention can be widely used in optoelectronic fields such as batteries, light emission, and detectors. Attached Figure Description

[0033] Figure 1 shows the X-ray diffraction pattern of the material obtained in Example 1;

[0034] Figure 2 shows a scanning electron microscope image obtained in Example 1;

[0035] Figure 3 shows the current-voltage (JV) efficiency curves of the perovskite solar cell prepared based on the perovskite crystals of Example 1.

[0036] Figure 4 shows the original X-ray diffraction pattern of the perovskite film before aging in Comparative Example 1.

[0037] Figure 5 shows a scanning electron microscope image of Comparative Example 1;

[0038] Figure 6 shows the efficiency current-voltage curve of the perovskite solar cell prepared based on the perovskite crystal of Example 1;

[0039] Figure 7 shows the X-ray diffraction pattern of the material obtained in Example 2;

[0040] Figure 8 shows the X-ray diffraction pattern of the material obtained in Example 3;

[0041] Figure 9 shows the X-ray diffraction pattern of the material obtained in Example 4;

[0042] Figure 10 shows the X-ray diffraction pattern of the material obtained in Example 5. Detailed Implementation

[0043] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0044] Example 1

[0045] This embodiment relates to a method of directly adding carbonate solvents to raw materials AX and BX2, utilizing the chemical reaction between the carbonate solvent and the catalyst amino salt to obtain high-quality perovskite crystal powder at room temperature. The specific steps are as follows:

[0046] 1) Mix 0.691g lead iodide (PbI2), 0.245g formamidine iodide (FAI), 0.020g cesium iodide (CsI), and 0.021g methylamine chloride (MACl) powder to obtain mixed powder A; the molar ratio of lead iodide, formamidine iodide, cesium iodide, and methylamine chloride is calculated to be 1:0.95:0.05:0.2.

[0047] 2) Add 1 ml of diethyl carbonate to the powder obtained in step 1) to obtain solution B. Then stir solution B for 10 min to obtain black powder solution C.

[0048] 3) After letting the solution containing black powder C stand for 1 hour, remove the supernatant to obtain black powder D;

[0049] 4) The black powder D obtained in step 3) is repeatedly washed with ether solvent 3 to 5 times to obtain high-purity black powder E.

[0050] 5) The solution E obtained in step 4) is dried under vacuum for 2 hours to obtain high-quality perovskite crystal powder F.

[0051] Figure 1 shows the X-ray diffraction pattern of Example 1, from which the FA obtained in Example 1 can be derived. 0.95 Cs 0.05PbI3 perovskite crystals have extremely high crystallinity; Figure 2 is a scanning electron microscope image of Example 1, and it can be seen from the surface of the image that the obtained crystal powders are all cubic crystals; Figure 3 is the JV curve of the perovskite battery prepared based on the perovskite crystals obtained in Example 1, and the results show that the perovskite battery prepared based on the perovskite crystals obtained in this invention can obtain a high-efficiency perovskite battery.

[0052] Comparative Example 1

[0053] The comparative method is the same as in Example 1, except that MACl is not introduced in step 1), and diethyl carbonate solution is replaced with the commonly used 2-methoxyethanol in step 2).

[0054] Figure 4 shows the X-ray diffraction pattern of Comparative Example 1. It can be seen that the perovskite crystal phase obtained in Comparative Example 1 not only has significantly reduced crystallinity but is also impure (containing both yellow and black phases). Figure 5 shows the morphology of the perovskite crystal obtained in Comparative Example 1, which contains not only black-phase perovskite but also strip-shaped yellow-phase perovskite. Figure 6 shows the JV curve of the perovskite solar cell prepared based on the perovskite crystal obtained in Comparative Example 1. The results indicate that the efficiency of the perovskite solar cell prepared based on the perovskite crystal obtained by the traditional method is significantly lower than that of the method of this invention.

[0055] Example 2

[0056] This embodiment relates to a method of directly adding carbonate solvents to raw materials AX and BX2, utilizing the chemical reaction between the carbonate solvent and the catalyst amino salt to obtain high-quality perovskite crystal powder at room temperature. The specific steps are as follows:

[0057] 1) Mix 0.691g PbI2, 0.258g FAI and 0.021g MACl powder to obtain mixed powder A; the above makes the molar ratio of PbI2, FAI and MACl 1:1:0.2.

[0058] 2) Add 1 ml of diethyl carbonate to the powder obtained in step 1) to obtain solution B. Then stir solution B for 10 min to obtain black powder solution C.

[0059] 3) After letting the solution containing black powder C stand for 1 hour, remove the supernatant to obtain black powder D;

[0060] 4) The black powder D obtained in step 3) is repeatedly washed with ether solvent 3 to 5 times to obtain high-purity black powder E.

[0061] 5) The solution E obtained in step 4) is dried under vacuum for 2 hours to obtain high-quality perovskite crystal powder F.

[0062] Figure 7 shows the X-ray diffraction pattern of Example 2, which shows that the FAPbI3 perovskite crystal obtained in Example 2 is not only phase-pure but also has extremely high crystallinity.

[0063] Example 3

[0064] This embodiment relates to a method of directly adding carbonate solvents to raw materials AX and BX2, utilizing the chemical reaction between the carbonate solvent and the catalyst amino salt to obtain high-quality perovskite crystal powder at room temperature. The specific steps are as follows:

[0065] 1) Mix 0.691g PbI2, 0.245g FAI, 0.020g CsI and 0.021g MACl powder to obtain mixed powder A; the above makes the molar ratio of PbI2, FAI, CsI and MACl 1:0.95:0.05:0.2.

[0066] 2) Add 1 ml of methyl ethyl carbonate to the powder obtained in step 1) to obtain solution B. Then stir solution B for 10 min to obtain black powder solution C.

[0067] 3) After letting the solution containing black powder C stand for 1 hour, remove the supernatant to obtain black powder D;

[0068] 4) The black powder D obtained in step 3) is repeatedly washed with ether solvent 3 to 5 times to obtain high-purity black powder E.

[0069] 5) The solution E obtained in step 4) is dried under vacuum for 2 hours to obtain high-quality perovskite crystal powder F.

[0070] Figure 8 shows the X-ray diffraction pattern of Example 3, from which the FA obtained in Example 3 can be derived. 0.95 Cs 0.05 PbI3 perovskite crystals are not only phase-pure, but also have extremely high crystallinity.

[0071] Example 4

[0072] This embodiment relates to a method of directly adding carbonate solvents to raw materials AX and BX2, utilizing the chemical reaction between the carbonate solvent and the catalyst amino salt to obtain high-quality perovskite crystal powder at room temperature. The specific steps are as follows:

[0073] 1) Mix 0.691g PbI2, 0.258g FAI and 0.021g MACl powder to obtain mixed powder A; the above makes the molar ratio of PbI2, FAI and MACl 1:1:0.2.

[0074] 2) Add 1 ml of methyl ethyl carbonate to the powder obtained in step 1) to obtain solution B. Then stir solution B for 10 min to obtain black powder solution C.

[0075] 3) After letting the solution containing black powder C stand for 1 hour, remove the supernatant to obtain black powder D;

[0076] 4) The black powder D obtained in step 3) is repeatedly washed with ether solvent 3 to 5 times to obtain high-purity black powder E.

[0077] 5) The solution E obtained in step 4) is dried under vacuum for 2 hours to obtain high-quality perovskite crystal powder F.

[0078] Figure 9 shows the X-ray diffraction pattern of Example 4, which shows that the FAPbI3 perovskite crystal obtained in Example 4 is not only phase-pure but also has extremely high crystallinity.

[0079] Example 5

[0080] This embodiment relates to a method of directly adding carbonate solvents to raw materials AX and BX2, utilizing the chemical reaction between the carbonate solvent and the catalyst amino salt to obtain high-quality perovskite crystal powder at room temperature. The specific steps are as follows:

[0081] 1) Mix 0.691g PbI2, 0.245g FAI, 0.020g CsI and 0.028g MACl powder to obtain mixed powder A; the above makes the molar ratio of PbI2, FAI, CsI and MACl 1:0.95:0.05:0.3.

[0082] 2) Add 1 ml of diethyl carbonate to the powder obtained in step 1) to obtain solution B. Then stir solution B for 10 min to obtain black powder solution C.

[0083] 3) After letting the solution containing black powder C stand for 1 hour, remove the supernatant to obtain black powder D;

[0084] 4) The black powder D obtained in step 3) is repeatedly washed with ether solvent 3 to 5 times to obtain high-purity black powder E.

[0085] 5) The solution E obtained in step 4) is dried under vacuum for 2 hours to obtain high-quality perovskite crystal powder F.

[0086] Figure 10 shows the X-ray diffraction pattern of Example 5, from which the FA obtained in Example 4 can be derived. 0.95 Cs 0.05 PbI3 perovskite crystals are not only phase-pure, but also have extremely high crystallinity.

[0087] In summary, the perovskite films prepared using the perovskite microcrystalline material obtained by the preparation method of the present invention have significantly improved stability compared to traditional perovskites, while maintaining the properties of the perovskite films themselves.

Claims

1. A method for preparing high-stable perovskite crystals by room-temperature spontaneous reaction, characterized in that, Includes the following steps: S1, mix halide salt AX, halide metal BX2 and catalyst amino salt to obtain mixed powder 1. In this context, A in halide salt AX represents inorganic and / or organic cations; B in metal halide BX2 represents divalent metal ions; and X represents halide anions. S2, add solvent to mixed powder 1 to obtain solution 2. The solvent is a carbonate solvent in which one of the carbon atoms simultaneously includes a C=O and two CO single bonds; S3, under room temperature conditions, stir solution 2 to react and obtain a mixture 3 containing perovskite crystal powder; after standing until the powder is completely precipitated, remove the supernatant to obtain black powder 4; wash black powder 4 with a solvent that is insoluble in perovskite to obtain black perovskite powder 5; vacuum dry the obtained black perovskite powder 5 to obtain microcrystalline perovskite powder 6, which is the highly stable perovskite crystal.

2. The method of claim 1, wherein the room-temperature spontaneous reaction is performed at a temperature of 20-30°C. In step S1, A in the halogenated salt AX is at least one of MA + , FA + , Cs + , and Rb + . B in the halogenated metal BX2is Pb 2+ and at least one of Sn 2+ and Sn X is at least one of I - , Br - , and Cl - .

3. The method of claim 2, wherein the room-temperature spontaneous reaction is performed at a temperature of 20-30°C. The catalyst amino salt is at least one of dimethylamine hydroiodate, methylamine iodide, and methylamine chloride.

4. The method of claim 3, wherein the room-temperature spontaneous reaction is performed at a temperature of 20-30°C. The molar ratio of halide salt AX, metal halide BX2 and auxiliary amino salt is 1:1:x, where x≥0.

2.

5. The method of claim 1, wherein the room-temperature spontaneous reaction is performed at a temperature of 20-30 °C. In step S2, the solvent is at least one of ethylene carbonate, diethyl carbonate, propylene carbonate, dimethyl carbonate, and ethyl methyl carbonate.

6. The method of claim 1, wherein the room-temperature spontaneous reaction is performed at a temperature of 20-30 °C. In step S2, the amount of solvent added is such that the molar concentration of both halide salt AX and halide metal BX2 is greater than 0.5 mol / L.

7. The method of claim 1, wherein the room-temperature spontaneous reaction is performed at a temperature of 20-30 °C. In step S3, the supernatant is removed by filtration or rotary evaporation.

8. The method of claim 1, wherein the room-temperature spontaneous reaction is performed at a temperature of 20-30 °C. In step S3, the mixture 3 is allowed to stand for 0.5 to 2 hours.

9. The method of claim 1, wherein the room-temperature spontaneous reaction is performed at a temperature of 20-30 °C. In step S3, the solvent for the insoluble perovskite is at least one of diethyl ether and acetonitrile.

10. The highly stable perovskite crystal prepared by the method according to any one of claims 1 to 9.

Images