Nanoscale localized contacts for high fill factors in polymer-passivated perovskite solar cells
Jun Peng, Daniel Walter, Yuhao Ren, Mike Tebyetekerwa, Yiliang Wu, The Duong, Qiaoling Lin, Juntao Li, Teng Lü, Md Arafat Mahmud, Olivier Lee Cheong Lem, Shenyou Zhao, Wenzhu Liu, Yun Liu, Heping Shen, Li Li, Felipe Kremer, Hieu T. Nguyen, Duk‐Yong Choi, Klaus Weber, Kylie Catchpole, Thomas P. White
Abstract
Polymer passivation layers can improve the open-circuit voltage of perovskite solar cells when inserted at the perovskite-charge transport layer interfaces. Unfortunately, many such layers are poor conductors, leading to a trade-off between passivation quality (voltage) and series resistance (fill factor, FF). Here, we introduce a nanopatterned electron transport layer that overcomes this trade-off by modifying the spatial distribution of the passivation layer to form nanoscale localized charge transport pathways through an otherwise passivated interface, thereby providing both effective passivation and excellent charge extraction. By combining the nanopatterned electron transport layer with a dopant-free hole transport layer, we achieved a certified power conversion efficiency of 21.6% for a 1-square-centimeter cell with FF of 0.839, and demonstrate an encapsulated cell that retains ~91.7% of its initial efficiency after 1000 hours of damp heat exposure.