Preparation method of perovskite powder

Abstract

The invention provides a preparation method of perovskite powder. The preparation method comprises the following steps: mixing raw materials including organic ammonium salt, lead halide, methyl ammonium halide and a solvent to obtain a perovskite powder system; sequentially carrying out after-treatment of solid-liquid separation, cleaning and drying on the perovskite powder system to obtain perovskite powder; wherein the solvent is selected from any one or more of propylene carbonate, dimethyl carbonate, ethylene carbonate, diethyl carbonate and methyl ethyl carbonate; the mixing temperature is 25-60 DEG C; according to the invention, the phase change barrier of the two-dimensional perovskite is overcome by adopting the energy released by the reaction between the additive and the solvent. Homogeneous mixing and reaction of perovskite precursor raw materials are promoted through a mixing means, and finally rapid synthesis of the two-dimensional perovskite powder at a low temperature is achieved. The method has the advantages of simple process, low cost, no need of accurate temperature control means, adoption of a completely green solvent, no environmental pollution and realization of large-scale production.

Description

Technical Field

[0001] The present invention relates to the technical field of perovskite solar cells, and in particular, to a method for preparing perovskite powder. Background Art

[0002] Due to their unique optoelectronic properties and higher stability than three-dimensional perovskites, two-dimensional halide perovskite materials have been widely studied in optoelectronic devices in recent years. Although there are currently many methods for synthesizing two-dimensional perovskites, such as synthesizing two-dimensional perovskite single crystals by using HI / H 3 PO 2 dissolving lead compounds and organic amines; or preparing two-dimensional perovskite thin films by spin coating. However, these synthesis methods require the use of toxic chemical reagents such as N,N-dimethylformamide (DMF) or corrosive solvents such as HI, and the single crystal synthesis process often requires heating and precise control of the heating rate, resulting in a long synthesis time and high energy consumption, which is not suitable for large-scale preparation.

[0003] Therefore, there is an urgent need to develop a new method to solve the above technical problems. Summary of the Invention

[0004] The main object of the present invention is to provide a method for preparing perovskite powder to solve the problems of large environmental pollution, low synthesis efficiency and high energy consumption in the existing method for preparing perovskite powder.

[0005] To achieve the above object, according to one aspect of the present invention, there is provided a method for preparing perovskite powder, the preparation method comprising: mixing raw materials including organic ammonium salt, lead halide, methylammonium halide and a solvent to obtain a perovskite powder system; performing post-treatment of solid-liquid separation, washing and drying on the perovskite powder system in sequence to obtain perovskite powder; wherein the solvent is selected from any one or more of propylene carbonate, dimethyl carbonate, ethylene carbonate, diethyl carbonate and ethyl methyl carbonate; the temperature of mixing is 25-60°C.

[0006] Further, the above mixing method is selected from one or more of ultrasonic mixing, stirring mixing and oscillating mixing.

[0007] Further, when the above mixing method is ultrasonic mixing, the frequency of ultrasonic mixing is 20-100 kHz, and the time of ultrasonic mixing is 1-60 min.

[0008] Further, when the above mixing method is stirring mixing, the rotation speed of stirring mixing is 100-1500 rpm, and the time of stirring mixing is 1-60 min.

[0009] Further, when the above mixing method is oscillating mixing, the rotation speed of the oscillating mixing is 500-2000 rpm, and the time of the oscillating mixing is 2-30 min.

[0010] Further, the molar ratio of the above-mentioned methylammonium halide salt to the lead halide salt is 5-40:100.

[0011] Further, the above-mentioned organic ammonium salt is selected from any one of phenethylammonium halide, m-fluorophenethylammonium halide, o-fluorophenethylammonium halide, butylammonium halide, octanediylammonium halide, and octylammonium halide.

[0012] Further, the concentration of Pb 2+ in the above-mentioned perovskite powder is 0.4-2 mol / L.

[0013] Further, the halogen in the above-mentioned methylammonium halide salt is selected from any one or more of I - , Br - , and Cl - .

[0014] Further, the halogen in the above-mentioned lead halide is selected from any one or more of I - , Br - , and Cl - .

[0015] Applying the technical solution of the present invention, the present application discloses a preparation method of perovskite powder. By using the energy released from the reaction between the additive and the solvent, the phase transition barrier of the two-dimensional perovskite is overcome, and a self-driven reaction is realized. The homogeneous mixing and reaction of the perovskite precursor raw materials are promoted by a mixing means, and finally the rapid synthesis of the two-dimensional perovskite powder at a lower temperature is realized. This method has simple process, low cost, does not require precise temperature control means, uses completely green solvents, has no environmental pollution, and can realize large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The specification drawings constituting a part of the present application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0017] Figure 1 shows the ultraviolet-visible absorption spectrum of a perovskite powder provided in Example 1 of the present invention;

[0018] Figure 2 shows the ultraviolet-visible absorption spectrum of a perovskite powder provided in Example 2 of the present invention;

[0019] Figure 3 shows the ultraviolet-visible absorption spectrum of a perovskite powder provided in Example 3 of the present invention;

[0020] Figure 4 Shows the ultraviolet-visible absorption spectrum of a perovskite powder provided according to Embodiment 4 of the present invention;

[0021] Figure 5 Shows the ultraviolet-visible absorption spectrum of a perovskite powder provided according to Embodiment 5 of the present invention;

[0022] Figure 6 Shows the photoluminescence spectrum of a perovskite powder provided according to Embodiment 6 of the present invention;

[0023] Figure 7 Shows the photoluminescence spectrum of a perovskite powder provided according to Embodiment 7 of the present invention. Detailed implementation manners

[0024] It should be noted that, without conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the drawings and in conjunction with the embodiments.

[0025] As analyzed in the background art of this application, the existing preparation methods of perovskite powder have problems of large environmental pollution, low synthesis efficiency and high energy consumption. To solve the above problems, this application provides a preparation method of perovskite powder.

[0026] In a typical implementation manner of this application, a preparation method of perovskite powder is provided. The preparation method includes: mixing raw materials including organic ammonium salt, lead halide, additive and solvent to obtain a perovskite powder system; performing post-treatments of solid-liquid separation, washing and drying on the perovskite powder system in sequence to obtain perovskite powder; wherein, the solvent is selected from any one or more of propylene carbonate, dimethyl carbonate, ethylene carbonate, diethyl carbonate and methyl ethyl carbonate; the temperature of mixing is 25-60°C.

[0027] This application discloses a preparation method of perovskite powder, which overcomes the phase transition barrier of two-dimensional perovskite by using the energy released from the reaction between the additive and the solvent. The homogeneous mixing and reaction of perovskite precursor raw materials are promoted by mixing means, and finally the rapid synthesis of two-dimensional perovskite powder at a lower temperature is realized. This method has simple process, low cost, does not require precise temperature control means, uses completely green solvents, has no environmental pollution, and can realize large-scale production.

[0028] In an embodiment of this application, the above mixing method is selected from one or more of ultrasonic mixing, stirring mixing and oscillating mixing.

[0029] Adopting the above-mentioned multiple methods is more helpful to make the raw materials of organic ammonium salts, lead halide salts, methylammonium halide salts and solvents more uniformly mixed according to actual requirements.

[0030] In an embodiment of the present application, when the above-mentioned mixing method is ultrasonic mixing, the frequency of ultrasonic mixing is 20 - 100 kHz, and the time of ultrasonic mixing is 1 - 60 min.

[0031] Ultrasonic mixing treatment can destroy the bubbles in the raw material solution, accelerate the diffusion and collision of raw material molecules, and promote the nucleation and growth of perovskite crystals faster. Preferably controlling the ultrasonic treatment time within the above range is beneficial to the balance of crystal nucleation and growth, and can optimize the crystallinity and particle size distribution of perovskite powder.

[0032] In an embodiment of the present application, when the above-mentioned mixing method is stirring mixing, the rotation speed of stirring mixing is 100 - 1500 rpm, and the time of stirring mixing is 1 - 60 min.

[0033] In an embodiment of the present application, when the above-mentioned mixing method is shaking mixing, the rotation speed of shaking mixing is 500 - 2000 rpm, and the time of shaking mixing is 2 - 30 min.

[0034] Preferably, stirring mixing or shaking mixing within the above range helps to uniformly disperse the raw materials in the solution, prevent local over-concentration or over-dilution, and ensure the uniform distribution and refinement of crystals after ultrasonic treatment. A reasonable combination of rotation speed and time can reduce the excessive aggregation of perovskite crystals, while promoting the refinement and dispersion of crystals, and improving the processing performance of the powder. Therefore, by controlling the rotation speed and time of stirring treatment within the above range, the morphology of perovskite powder can be further optimized, aggregation can be reduced, and the dispersibility and consistency of the powder can be improved.

[0035] In an embodiment of the present application, in the above-mentioned step S1, the molar ratio of methylammonium halide salt to lead halide salt is 5 - 40:100.

[0036] The reaction between methylammonium halide salt and the solvent releases energy, which promotes the formation of two-dimensional perovskite powder. An appropriate ratio helps to ensure both the energy required for the formation of two-dimensional perovskite and that methylammonium halide does not enter the perovskite lattice, without affecting the purity of perovskite powder. Therefore, preferably controlling the molar ratio of methylammonium halide salt to lead halide salt within the above range helps to promote the preparation of perovskite materials.

[0037] In an embodiment of the present application, in the above-mentioned step S1, the organic ammonium salt is selected from any one or more of phenethyl halide amine, m-fluorophenethyl halide amine, o-fluorophenethyl halide amine, butyl halide amine, octanedioyl halide amine and octyl halide amine.

[0038] Different organic ammonium salts introduce different organic spacer layers into the perovskite structure, which not only affects the bandgap of the material but also its stability in the environment. Therefore, by controlling the type of organic ammonium salt within the above range, it is beneficial to further improve the optoelectronic properties and stability of perovskite, especially for the formation and performance improvement of two-dimensional perovskite structures.

[0039] In one embodiment of the present application, the concentration of Pb 2+ in the above perovskite powder is 0.4 - 2 mol / L.

[0040] Pb 2+ The concentration directly determines the nucleation rate and growth rate of perovskite crystals. Too low a concentration may lead to slow crystal growth, while too high a concentration may lead to too fast crystal growth and the formation of irregular crystals. Therefore, by controlling the concentration of Pb 2+ in the precursor mixture within the above range, it is beneficial to improve the crystallization rate and morphology of the perovskite powder, thereby improving its optoelectronic properties.

[0041] In one embodiment of the present application, the halogen in the above methylammonium halide salt is selected from any one or more of I - 、Br - and Cl - .

[0042] In one embodiment of the present application, the halogen in the above lead halide salt is selected from any one or more of I - 、Br - and Cl - .

[0043] Lead salts with different halogens will affect the bandgap of the final material during the preparation of perovskite. I - provides a narrow bandgap, Cl - provides a wide bandgap, and Br - is in between. Therefore, by controlling the type of lead halide salt within the above range, it helps to finely adjust the bandgap of the perovskite powder to meet specific light absorption requirements.

[0044] In another typical embodiment of the present application, a perovskite powder is provided, which is prepared by the above preparation method.

[0045] Due to the adoption of the above innovative preparation method, combined with the raw material selection, solvent selection, and control of the mixing temperature conditions in the above method, the prepared perovskite powder has fewer surface defects, higher crystallinity, and better size distribution, and these properties together improve the optoelectronic properties and stability of the material.

[0046] In one embodiment of the present application, the general chemical formula of the above perovskite powder is A2 BX 4 ; wherein, A is selected from any one or more of phenethylammonio, 3-fluorophenethylammonio, 2-fluorophenethylammonio, butylamino, octanediamino and octylamino; B is Pb 2+ , and X is selected from any one or more of - I - , Br - and Cl

[0047] A 2 BX 4 The general chemical structure formula of ensures the basic framework of the perovskite material, while the selection of A, B, and X components allows for fine-tuning of the optoelectronic properties and stability of the material. By controlling these components, perovskite powders with specific bandgaps, high absorption efficiencies, and high stabilities can be obtained, which are crucial for the preparation of high-performance optoelectronic devices. Therefore, by controlling the chemical structure and composition of the perovskite powder, the performance consistency of the material is improved, thereby enhancing its reliability and efficiency in photovoltaic device applications.

[0048] The beneficial effects of the present application will be further described below in conjunction with embodiments.

[0049] Example 1

[0050] Weigh 400.62 mg of 3-fluorophenethylammonium iodide (m-F-PEAI), 691.52 mg of PbI 2 and 20.26 mg of CH 3 NH 3 Cl (with a molar ratio of 20% to PbI 2 ), add 1 mL of propylene carbonate, and ultrasonically mix at a frequency of 40 kHz for 5 min to obtain a mixed solution of two-dimensional perovskite (m-F-PEA 2 PbI 4 ) and propylene carbonate. Let the mixed solution stand and pour off the supernatant. Wash the two-dimensional perovskite with diethyl ether, centrifuge three times at 2000 rpm for 30 s, pour off the diethyl ether, and vacuum-dry the two-dimensional perovskite powder at 60 °C for 2 h to obtain the perovskite powder, whose ultraviolet-visible absorption spectrum is as shown in Figure 1 shown.

[0051] Example 2

[0052] Weigh 373.63 mg of phenethylammonium iodide (PEAI), 691.52 mg of PbI 2 and 20.26 mg of CH 3 NH 3 Cl (with a molar ratio of 20% to PbI 2(with a molar ratio of 20%) and 1 mL of propylene carbonate were added, and the ultrasonic mixing frequency was 40 kHz. After ultrasonic mixing for 5 min, a mixed solution of two-dimensional perovskite (PEA 2 PbI 4 ) and propylene carbonate was obtained. The mixed solution was allowed to stand, and the supernatant was poured off. The two-dimensional perovskite was washed with ether and centrifuged three times at 2000 rpm for 30 s. The ether was poured off, and the two-dimensional perovskite powder was vacuum-dried at 60 °C for 2 h to obtain perovskite powder, and its ultraviolet-visible absorption spectrum is as Figure 2 shown.

[0053] Example 3

[0054] 603.15 mg of butylammonium iodide (BAI), 691.52 mg of PbI 2 and 20.26 mg of CH 3 NH 3 Cl (with a molar ratio of 20% to PbI 2 ) were weighed and 1 mL of propylene carbonate was added. The ultrasonic mixing frequency was 40 kHz, and ultrasonic mixing was carried out for 5 min to obtain a mixed solution of two-dimensional perovskite (BA 2 PbI 4 ) and propylene carbonate. The mixed solution was allowed to stand, and the supernatant was poured off. The two-dimensional perovskite was washed with ether and centrifuged three times at 2000 rpm for 30 s. The ether was poured off, and the two-dimensional perovskite powder was vacuum-dried at 60 °C for 2 h to obtain perovskite powder, and its ultraviolet-visible absorption spectrum is as Figure 3 shown.

[0055] Example 4

[0056] The difference from Example 1 is that ultrasonic mixing was replaced by shaking mixing at 1000 rpm for 10 min, and finally perovskite powder was obtained, and its ultraviolet-visible absorption spectrum is as Figure 4 shown.

[0057] Example 5

[0058] The difference from Example 2 is that ultrasonic mixing was replaced by stirring mixing at 500 rpm for 5 min, and finally perovskite powder was obtained, and its ultraviolet-visible absorption spectrum is as Figure 5 shown.

[0059] Example 6

[0060] The difference from Example 1 is that the molar ratio of CH 3 NH 3 Cl to PbI 2 was 40%, and finally perovskite powder was obtained, and its photoluminescence spectrum is as Figure 6 shown.

[0061] Example 7

[0062] The difference from Example 2 is that the molar ratio of CH 3 NH 3 Cl to PbI 2 is 5%, and finally perovskite powder is obtained. Its photoluminescence spectrum is as shown in Figure 7 the figure.

[0063] Comparative Example 1

[0064] The difference from Example 1 is that the solvent is HI, and two-dimensional m-F-PEA 2 PbI 4 perovskite powder cannot be obtained.

[0065] Comparative Example 2

[0066] The difference from Example 1 is that CH 3 NH 3 Cl is not added, and two-dimensional m-F-PEA 2 PbI 4 perovskite powder cannot be obtained.

[0067] Performance test:

[0068] The absorption spectrum of the sample is measured by using an ultraviolet-visible spectrophotometer, and the photoluminescence spectrum of the sample is measured by using a fluorescence spectrometer. From Figures 1 to 7 the test results, it can be seen that two-dimensional perovskite powder can be prepared by using the preparation method of the present application.

[0069] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0070] The present application discloses a preparation method of perovskite powder. By using the energy released by the reaction between an additive and a solvent, the phase transition barrier of two-dimensional perovskite is overcome. The homogeneous mixing and reaction of perovskite precursor raw materials are promoted by a mixing means, and finally the rapid synthesis of two-dimensional perovskite powder at a lower temperature is realized. This method has a simple process, low cost, does not require precise temperature control means, uses a completely green solvent, has no environmental pollution, and can realize large-scale production.

[0071] The above are only the embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing perovskite powder, characterized in that: The preparation method comprises: Mixing raw materials including an organic ammonium salt, a lead halide salt, a methylammonium halide salt and a solvent to obtain a perovskite powder system; The perovskite powder system is subjected to post-treatments of solid-liquid separation, washing and drying in sequence to obtain the perovskite powder; Wherein, the solvent is selected from any one or more of propylene carbonate, dimethyl carbonate, ethylene carbonate, diethyl carbonate and ethyl methyl carbonate; The mixing temperature is 25-60°C.

2. The preparation method according to claim 1, characterized in that: The mixing method is selected from one or more of ultrasonic mixing, stirring mixing and oscillating mixing.

3. The preparation method according to claim 2, characterized in that: When the mixing method is ultrasonic mixing, the frequency of the ultrasonic mixing is 20 to 100 kHz, and the time of the ultrasonic mixing is 1 to 60 minutes.

4. The preparation method according to claim 2, characterized in that: When the mixing method is stirring and mixing, the rotation speed of the stirring and mixing is 100 to 1500 rpm, and the time of the stirring and mixing is 1 to 60 minutes.

5. The preparation method according to claim 2, characterized in that: When the mixing method is oscillating mixing, the rotation speed of the oscillating mixing is 500 to 2000 rpm, and the time of the oscillating mixing is 2 to 30 minutes.

6. The preparation method according to any one of claims 1 to 5, characterized in that The molar ratio of the methylammonium halide to the lead halide is 5 to 40:

100.

7. The preparation method according to any one of claims 1 to 6, characterized in that The organic ammonium salt is selected from any one of phenethylamine halide, m-fluorophenethylamine halide, o-fluorophenethylamine halide, butylamine halide, octanediylamine halide and octylamine halide.

8. The preparation method according to any one of claims 1 to 7, characterized in that The perovskite powder contains Pb 2+ The concentration is 0.4~2mol / L.

9. The preparation method according to any one of claims 1 to 8, characterized in that: The halogen in the methylammonium halide is selected from: - Br - and Cl - Any one or more of .

10. The preparation method according to any one of claims 1 to 9, characterized in that: The halogen in the lead halide is selected from: - Br - and Cl - Any one or more of .

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