Acetone complexes for high-performance perovskite photovoltaics with reduced nonradiative recombination

Solvent engineering has been widely employed in the preparation of high-quality perovskite films for emerging halide perovskite solar cells (PSCs). However, the heavy use of toxic solvents (such as N-methyl-2-pyrrolidone (NMP), N,N-dimethylformamide (DMF), etc.) has caused critical concerns for health and the environment. Herein, a greener solvent acetone was applied to partially replace DMF and NMP for depositing high-quality perovskite thin films. During the film deposition, an acetone-MAI-PbI2 intermediate was formed to modulate the crystallization process and reduce the grain boundary gaps to achieve high quality perovskite films. The results of photoluminescence spectroscopy, transient photovoltage decay, and Mott-Schottky analysis indicated that this solvent engineering with acetone enabled suppressed trap-assisted nonradiative recombination and facilitated the charge extraction in the corresponding PSC devices. Consequently, the target devices achieved a power conversion efficiency (PCE) of 19.45%, and the open-circuit voltage was enhanced by 70 mV due to the reduced nonradiative recombination. This work provides an idea to alleviate the toxicity of processing solvents that hinders the mass production of PSCs.