Vertical grain-shape engineering for high-efficiency and stable perovskite solar cells
Yifeng Shi, Yifan Zheng, Xun Xiao, Pengxiang Wang, Guodong Zhang, Qingyuan Li, Ge Zhang, Yuchuan Shao
Abstract
In recent years, perovskite solar cells have undergone rapid improvements in power conversion efficiency (PCE), advancing the development of next-generation photovoltaic technology. However, the presence of interfacial defects, which are prevalent during the film formation process, poses a persistent hurdle to the further improvement of device performance. While defect issues could be alleviated by introducing passivation strategies, the non-uniform dimensions of the top and bottom grain size may still result in unbalanced charge transport. Here, we present a vertical grain-shape engineering (VGE) approach based on anilinium hypophosphite (AHP) to control the vertical growth of perovskite grains. We successfully fabricate a pinhole-free perovskite film with monolithic crystalline structures, demonstrating uniform grain sizes exceeding 2 μm at both the top and bottom surfaces. Champion PCEs of 22.14% and 18.06% are obtained for small-scale (0.08 cm2) and mini-module (aperture area of 14 cm2) blade-coated FAPbI3-based PSCs, respectively.