High-Efficiency and Stable Perovskite Solar Cells Prepared Using Chlorobenzene/Acetonitrile Antisolvent.

Preparing high-quality perovskite film with large grain size and fewer trap states is of vital importance in boosting the efficiency and stability of perovskite solar cells (PSCs). However, it is still difficult to obtain perfect MAPbI3 films by antisolvent treatment so far because of the small grain size, pinholes, and numerous defects in perovskite layers. Herein, acetonitrile (ACN) was introduced into chlorobenzene (CB) antisolvent to modify the MAPbI3 active layer. The results show that the ACN could control the ratio of the DMSO in MAI-PbI2-DMSO intermediate phase film effectively and thus manipulate the formation of MAPbI3 film. Relatively high-quality perovskite films with larger grain size were obtained when we added 6% v/v ACN into CB antisolvent. Based on the ACN-modified MAPbI3 film, the n-i-p planar device with the structure of FTO/SnO2/MAPbI3/spiro-OMeTAD/Ag yields the best power conversion efficiency (PCE) of 18.9%. It exhibited an enhancement of 16.6% in efficiency compared with the PCE of 16.2% for the control device. In addition, the device based on ACN-modified MAPbI3 also presents improved stability in air atmosphere.