Toxic solvents will be used in the process of preparing perovskite polycrystalline films by solution method, and heat treatment is still the main way to induce perovskite grain growth, which will not only increase energy consumption, but also hinder the development of flexible solar cells. In order to eliminate the use of toxic solvents and high temperature process, the corresponding polycrystalline films were obtained by processing CsPbBr ₃nanocrystal films by low temperature solution, and applied to solar cells. Firstly, CsPbBr ₃nanocrystalline (nanocrystalline NC) ink precursor was prepared by hot injection method, and nanocrystalline film was prepared by spinning coating method. In atmospheric environment, CsPbBr ₃nanocrystalline films were prepared by saturated solution of Pb(SCN) ₂and NH ₄Br methyl acetate. The perovskite solar cell was prepared by using it as an absorbing layer, and the performance of the cell was effectively improved, and the efficiency of the cell reached 8.43%. The results show that the saturated solution of Pb(SCN) ₂and NH ₄Br methyl acetate (MA) can not only make nanocrystalline crystallization continue, but also effectively passivate the defects in the perovskite films. In the process of preparing CsPbBr ₃polycrystalline films, there is neither high temperature treatment nor the use of high boiling point toxic solvent, and it is suitable for the preparation of rigid and flexible solar cells.
The inorganic halide perovskite nanocrystals were developed and applied as “inks” to fabricate fully air-processed, electrically stable solar cells. Although the prepared film consists of mosaic nanocrystals capped with large amount of organic ligands and surface traps, the method provides a new pathway for single-step, large-scale fabrication of inorganic perovskite devices. Moreover, the flexible control of the material composition provides a platform to uncover the optimal conditions for optoelectronics and photonics.