SnO<sub><i>x</i></sub> as Bottom Hole Extraction Layer and Top In Situ Protection Layer Yields over 14% Efficiency in Sn-Based Perovskite Solar Cells
Liang Wang, Mengmeng Chen, Shuzhang Yang, Namiki Uezono, Qingqing Miao, Gaurav Kapil, Ajay Kumar Baranwal, Yoshitaka Sanehira, Dandan Wang, Dong Liu, Tingli Ma, K. Ozawa, T. Sakurai, Zheng Zhang, Qing Shen, Shuzi Hayase
Abstract
Sn-based perovskite solar cells (S-PSCs) are a promising candidate to replace toxic Pb-based PSCs. For promoting their industrial application, developing inorganic substitutions of unstable poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) is also an important part due to its intrinsic stability and low cost. Here, we in situ prepared ambipolar SnOx by a simple and fast plasma-assistant strategy (P-SnOx). The as-prepared P-SnOx works as a hole transport layer directly, yielding a 10.89 ± 0.51% power conversion efficiency (PCE) comparable to a PEDOT:PSS-based device (10.39 ± 0.72%). The top SnOx (T-SnOx), composed of SnO2 and Sn metal, as a modifier and a protection layer of the perovskite by reducing Sn4+ to Sn2+, gives a 13.08 ± 0.33% device performance. This in situ top protective strategy combined with P-SnOx as a hole transport layer further boosts the champion PCE of S-PSCs to 14.09% (13.5 ± 0.32%).