The Effect of Antisolvent Dropping Delay Time on The Morphology and Structure of the Perovskite Layer in the Hole Transport Material Free Perovskite Solar Cells

Antisolvent-assisted one-step spin coating approach has been investigated as an effective method for the preparation of perovskite solar cells (PSC) under ambient conditions. The influence of antisolvent dropping delay time on the final morphology was investigated. The photovoltaic device with FTO/TiO2 block/TiO2-mp/CH3NH3PbI3/Au structure was fabricated, and the impact of different delay times on the morphology of CH3NH3PbI3 layers were examined. The hole transport materials (HTM) free PSC with optimal antisolvent dropping delay time exhibited open-circuit voltage (Voc) of 0.76 V with power conversion efficiency (PCE) of  3.54 %, which were much higher than those of the PSC fabricated without antisolvent treatment (Voc of  0.64 V and PCE of 1.51 %). Scanning electron microscopy and X-ray diffraction were used to study the morphology and structure of the CH3NH3PbI3 films. Photocurrent-voltage curves were plotted to investigate the photoelectric properties, carrier transfer, and recombination process in the fabricated perovskite solar cells. Our findings indicated that the proposed antisolvent-assisted one-step spin coating approach can provide a high-performance atmospheric method for fabrication of low-cost HTM-free perovskite solar cells.