Buried-in interface with two-terminal functional groups for perovskite-based photovoltaic solar cells

Abstract

Interface plays an important role in perovskite solar cells. Herein, a functional molecular with two-terminal donor groups was deposited between the tin oxide (SnO2) electron transport layer and halide perovskite to induce the perovskite crystal growth and passivate defects at the interface. It is found that isonicotinohydrazide (INHA) can anchor Pb2+ cluster in precursor and promote uniform nucleation, which helps to adjust the crystal growth in perovskite films. As well, more analysis shows that interfacial modification can greatly reduce trap defects and therefore facilitate photogenerated carrier-transferring. The efficient electron transfer and reduced interface traps correlate well with the corresponding fill factors and open-circuit voltages (VOC) of working devices. The resulting perovskite solar cell exhibits striking improvements to reach the champion efficiency of 21.12%. The long-term stability is also significantly enhanced by comparing to the pristine devices. This work highlights the effect of INHA/perovskite interfacial interaction and provides a multi-functional passivation strategy for further perfecting perovskite films.