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CN-121976281-A - Method for obtaining high-purity perovskite single crystal powder from low-purity raw material

CN121976281ACN 121976281 ACN121976281 ACN 121976281ACN-121976281-A

Abstract

The invention discloses a method for obtaining high-purity perovskite single crystal powder from low-purity raw materials, which comprises the following steps of 1, dissolving halogenated organic salt and lead salt into an organic solvent, wherein the molar ratio of the halogenated organic salt to the lead salt is 1:1, forming a perovskite solution with the concentration of 0.8-1.2M, 2, heating the perovskite solution to form a hot perovskite solution, 3, continuously heating and stirring the hot perovskite solution, dripping a perovskite anti-solvent, 4, continuously heating until crystals are not separated out, removing supernatant, 5, injecting excessive ethyl acetate solution to wash the powder, repeating for 2-3 times, and 6, drying the perovskite powder in a vacuum drying box to obtain perovskite crystal powder, wherein the perovskite crystal has high growth speed, high yield and good quality.

Inventors

  • WANG SHUBO
  • ZHOU PIN
  • FEI FEI
  • CHEN XIAOHUI
  • ZHANG QIAN

Assignees

  • 常州工学院

Dates

Publication Date
20260505
Application Date
20230906

Claims (8)

  1. 1. A method for obtaining high-purity perovskite single crystal powder from low-purity raw materials is characterized by comprising the following steps: Step 1, dissolving halogenated organic salt and lead salt into an organic solvent, wherein the molar ratio of the halogenated organic salt to the lead salt is 1:1, and forming perovskite solution with the concentration of 0.8-1.2M; step 2, heating the perovskite solution to form a hot perovskite solution; step 3, continuously heating and stirring the hot perovskite solution, and dripping a perovskite anti-solvent; Step 4, heating continuously until crystals are not separated out any more, and removing supernatant; Step 5, injecting excessive ethyl acetate solution to wash the powder, and repeating for 2-3 times; And 6, drying the perovskite powder in a vacuum drying oven to obtain perovskite crystal powder.
  2. 2. A method of obtaining a high purity perovskite single crystal powder from a low purity feedstock as set forth in claim 1 wherein said halogenated organic salt is one of FAX, MAX, wherein X is Br or I, said lead salt is one of PbI 2 、PbBr 2 , and the perovskite has a chemical formula of FAPbI 3-x Br x or MAPbI 3-x Br x, x=any number between 0 and 3.
  3. 3. A method for obtaining a high purity perovskite single crystal powder from a low purity feedstock as set forth in claim 1 wherein said organic solvent is one of GBL (gamma-butyrolactone), 2-ME (2-methylethanol), GVL (gamma valerolactone), acetonitrile (ACN), different solvents are selected depending on the type of perovskite being produced, FA-based perovskite is selected from GBL and 2-ME, MA-based perovskite is selected from GVL and ACN.
  4. 4. A method for obtaining high purity perovskite single crystal powder from low purity feedstock as claimed in claim 1 wherein in step 2 the perovskite solution is heated to above 150 ℃.
  5. 5. A method for obtaining a high purity perovskite single crystal powder from a low purity raw material according to claim 1, wherein in step 3, the perovskite anti-solvent is dropped by inserting a tube into which the anti-solvent is injected into the bottom of the solution, and slowly dropping the perovskite anti-solvent dropwise.
  6. 6. A process for obtaining high purity perovskite single crystal powder from low purity feedstock as claimed in claim 1 or 5 wherein said perovskite anti-solvent is a solution having reducing properties such as formic acid or acetic acid.
  7. 7. A process for obtaining a high purity perovskite single crystal powder from a low purity starting material as claimed in claim 1 or 6 wherein the volume ratio of perovskite anti-solvent to perovskite solution is (0.1-0.4): 1.
  8. 8. A process for obtaining a high purity perovskite single crystal powder from a low purity raw material as claimed in claim 1 wherein in step 3, the hot perovskite solution is continuously heated and stirred, and excess formaldehyde gas is bubbled into the perovskite solution by bubbling until no perovskite crystals are precipitated.

Description

Method for obtaining high-purity perovskite single crystal powder from low-purity raw material Technical Field The invention relates to the technical field of solar cells, in particular to a method for obtaining high-purity perovskite single crystal powder from low-purity raw materials. Background Perovskite solar cells are of great interest because of their low cost, high efficiency, and simple fabrication. Currently, the predominant method of preparing perovskite solar cells is the solution method. The solution method is to dissolve precursors such as lead salt, organic salt and the like into an organic solvent to form perovskite solution, and then form a perovskite film through a series of processes such as coating, spin coating, post-treatment and the like. Here, the purity of the lead salt and the organic salt plays a critical role, and the low-purity product cannot obtain the perovskite solar cell with high efficiency, while the high-purity product (more than 4N) is expensive, which limits the industrialized development of the perovskite solar cell. The preparation of high purity perovskite crystals by using low purity lead salts and organic salts, which are then dissolved to form perovskite solutions, is a potential purification method. However, the current temperature-rising crystallization method for preparing perovskite crystals is too slow in crystal preparation speed, about 1-3 hours, low in yield and low in yield (about 20%), and the perovskite crystals prepared by the ball milling process still need to use high-purity raw materials, so that the perovskite crystals are limited in industrial application as raw materials. Disclosure of Invention The invention aims to provide a method for obtaining high-purity perovskite single crystal powder from low-purity raw materials, which solves the problems of low growth speed, low yield and poor quality of perovskite crystals. The technical scheme for solving the problems is that the method for obtaining high-purity perovskite single crystal powder from low-purity raw materials specifically comprises the following steps: Step 1, dissolving halogenated organic salt and lead salt into an organic solvent, wherein the molar ratio of the halogenated organic salt to the lead salt is 1:1, and forming perovskite solution with the concentration of 0.8-1.2M; step 2, heating the perovskite solution to form a hot perovskite solution; step 3, continuously heating and stirring the hot perovskite solution, and dripping a perovskite anti-solvent; Step 4, heating continuously until crystals are not separated out any more, and removing supernatant; Step 5, injecting excessive ethyl acetate solution to wash the powder, and repeating for 2-3 times; And 6, drying the perovskite powder in a vacuum drying oven to obtain perovskite crystal powder. Further, the halogenated organic salt is one of FAX and MAX, wherein X is Br or I, the lead salt is one of PbI 2、PbBr2, and the perovskite has a chemical formula of FAPbI 3-xBrx or MAPbI 3-xBrx, x=any number between 0 and 3. Further, the organic solvent is one of GBL (gamma-butyrolactone), 2-ME (2-methyl ethanol), GVL (gamma-valerolactone) and Acetonitrile (ACN), different solvents are selected according to the type of perovskite prepared, the FA-based perovskite is selected from GBL and 2-ME, and the MA-based perovskite is selected from GVL and ACN. Further, in step 2, heating the perovskite solution to 150 ℃ or higher can improve the crystal precipitation rate, and can ensure production of black phase perovskite for FA-based perovskite. Further, in the step 3, the perovskite anti-solvent is dropwise added by inserting a tube for injecting the anti-solvent into the bottom of the solution, and slowly dropwise adding the perovskite anti-solvent, so that the anti-solvent can be dispersed in the whole solution system. Furthermore, the perovskite anti-solvent is a solution with reducibility, such as formic acid or acetic acid, and the solution with reducibility can ensure the precipitation of iodine simple substance in the reaction process. Further, the volume ratio of the perovskite anti-solvent to the perovskite solution is (0.1-0.4): 1, and if the reducing solution is insufficient, the precipitation of iodine simple substance cannot be completely inhibited, and if too much lead iodide is precipitated, the reaction is incomplete. In yet another embodiment, in step 3, the hot perovskite solution is continuously heated and stirred, and excess formaldehyde gas is bubbled into the perovskite solution by bubbling until perovskite crystals are not precipitated, and the reducing gas ensures the formation of elemental iodine during the reaction. The invention has the beneficial effects that: the invention provides a method for obtaining high-purity perovskite single crystal powder from low-purity raw materials, which has the advantages of high perovskite crystal growth speed, high yield and good quality. Drawings FIG. 1 is a graph of the photovo