Perovskite Self-Passivation with PCBM for Small Open-Circuit Voltage Loss

It is well known that [6,6]-phenyl-C61-butyric acid methyl\r\nester (PCBM) is a common n-type passivation material in PSCs, usually used as\r\nan interface modification layer. However, PCBM is extremely expensive and is\r\nnot suitable for future industrialization. Herein, the various concentrations\r\nof PCBM as an additive are adopted for PSCs. It not only avoids the routine\r\nprocess of spin coating the multi-layer films, but also reduces the PCBM\r\nmaterial and cost. Meanwhile, PCBM can passivate the grain surface and modulate\r\nmorphology of perovskite films. Furthermore, the most important optical\r\nparameters of solar cells, the current density (Jsc), fill factor (FF), open-circuit voltage (Voc) and power conversion\r\nefficiencies (PCE) were improved. Especially, when the PCBM doping ratio in CH3NH3PbI3 (MAPbI3) precursor solution was 1 wt%,\r\nthe device obtained the smallest Voc decay (less than 1%) in the p-i-n type PSCs with poly (3,4-ethylenedioxythiophene):poly\r\n(styrene sulfonate) (PEDOT:PSS) as hole transport layer (HTL) and fullerene (C60)\r\nas electron transport layer (ETL). The PSCs Voc stability improvement is attributed to\r\nenhanced crystallinity of photoactive layer and decreased non-radiative recombination\r\nby PCBM doping in the perovskites.