Synchronous effect of coordination and hydrogen bonds boosting the photovoltaic performance of perovskite solar cells

Abstract

Superior quality of perovskite film with perfect crystalline and low defect density is crucial for achieving excellent photovoltaic performance and durability of perovskite solar cells (PSCs), and regulation of growth of perovskite crystal and defects passivation by additive is remain challenge. Herein, two acyl molecules (Succinimide: SCI, and Hydantoin: HDT) were incorporated into perovskite precursor solution as additive. It can be found that the HDT molecule can not only passivate undercoordinated Pb2+ defects in perovskite films by the -C=O groups with coordination bonds, but also formed hydrogen bonds with I− by -NH- group, which effectively inhibited the formation of iodine vacancy defects and regulated growth rate of perovskite crystals, and the quality of perovskite films was optimized with enlarging grain size and reduced trap-density. Consequently, power conversion efficiency of HDT-based device was enhanced from 19.47 % to 21.00 %, with an enhancement of JSC and VOC. Moreover, the HDT-based device without encapsulation retained 83.7 % of its initial PCE after being aged at 10–20 % RH for 60 days. Obviously, such a study could provide a new strategy to optimize quality of perovskite film for boosting performance of PSCs.