Polymer additive assisted crystallization of perovskite films for high-performance solar cells

Perovskite solar cells (PSCs) have attracted much attention as a novel photoelectric converter. The quality of perovskite films plays a key role in the efficiency and stability. Among them, defects in the films surface restrict the performance of solar cells. Surface passivation is an effective route to eliminate defect of perovskite films. In this paper, we introduce PVB as a novel polymer additive, it can assist perovskite films with better crystallinity and morphology, as well as less defects. Perovskite solar cells with 1.5 mg/mL optimized concentration PVB exhibit power conversion efficiency (PCE) of 19.04% than 16.34% of control cells. Meanwhile, the cells with PVB demonstrate less hysteresis than that without additive, as well as excellent reproducibility. Additionally, perovskite solar cells based on PVB can retain around 90% of its original efficiency under fully ambient air of 65 +/- 5% relative humidity or under 65 degrees C after aging for 30 days. The finding provides a potential additive candidate for fabrication of higher performance devices.