Optimization of Ag/PCBM interface via solvent treatment for efficient perovskite solar cell

The energy gap between 6,6-phenyl-C61-butyric acid methyl ester (PCBM) and silver (Ag) is disadvantage to the electron collection of perovskite solar cells (PSCs). In this work, solvent treatment is applied on the surface of PCBM by using ethanol, acetonitrile and ethanol:5 vol% acetonitrile, respectively. Experimental results showed that solvent treatment greatly enhanced the power conversion efficiency (PCE) of PSCs. After ethanol:5 vol% acetonitrile treatment, the PCE of PSC increased from 14.03 ± 0.23 % to 17.03 ± 0.13 % due to the simultaneously enhancement of VOC, JSC and FF. Electronic energy level at the surface of PCBM, electron mobility of PCBM film and the dark current density of PSCs were analysed to investigate the work mechanism of solvent treatment.