Buried-in Interface with Two-terminal Functional Groups for Perovskite- based Photovoltaic Solar Cells

Abstract Interface plays an important role in determining the optoelectronic properties of perovskite film to access efficiency photovoltaic device. Herein, a functional molecular with two-terminal donor groups was deposited between the SnO2 electron transport layer and halide perovskite to manipulate the perovskite crystal growth and passivate defects at the interface. It’s found that isonicotinohydrazide (INHA) can anchor Pb2+ cluster in precursor against the harsh perovskite ingredient exhaustion, leading to a uniform nuclei distribution for crystal growth in the whole perovskite film. Growth manipulation give rise to confinement induced dynamical crystallization process leading a uniform perovskite film from bottom to top. 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 compared to pristine devices. This work highlights the origin of INHA/perovskite interfacial interaction and offer a growth model for further perfecting perovskite films.