Thermal Cross-Linking Hole-Transport Self-Assembled Monolayers for Perovskite Solar Cells
Wanhai Wang, Xiaofeng Li, Liang Gao, Gaoqi Liu, Yang Li, Wei Zhou, Jianfei Hu, Yinhu Gao, Yuliang Che, Zhijun Ning, Jinbao Zhang, Weihua Tang
Abstract
Inverted perovskite solar cells (PSCs) adopting hole-transport self-assembled monolayers (SAMs) face the challenge of inadequate interfacial affinity and inherent instability. A thermal cross-linking SAM design strategy is herein reported to simultaneously improve their surface wettability and thermal stability. The in situ cross-linking networks of molecular-engineered SAMs promote charge transport at the perovskite buried interface. A champion efficiency of 24.17% was achieved for 1.56 eV bandgap PSCs, outperforming non-cross-linked counterparts (22.02%). Over 90% initial efficiency was retained after 1000 h of exposure at 100 °C. Cross-linked SAMs also endow 1.25 eV PSCs with an impressive efficiency of 22.05%. This research offers valuable insights for designing inherently stable SAMs to promote the development of inverted PSCs.