Polymer-acid-metal quasi-ohmic contact for stable perovskite solar cells beyond a 20,000-hour extrapolated lifetime
Junsheng Luo, Bowen Liu, Haomiao Yin, Xin Zhou, Mingjian Wu, Hongyang Shi, Jiyun Zhang, Jack Elia, Kaicheng Zhang, Jianchang Wu, Zhiqiang Xie, Chao Liu, Junyu Yuan, Zhongquan Wan, Thomas Heumueller, Larry Lüer, Erdmann Spiecker, Ning Li, Chunyang Jia, Christoph J. Brabec, Yicheng Zhao
Abstract
Abstract The development of a robust quasi-ohmic contact with minimal resistance, good stability and cost-effectiveness is crucial for perovskite solar cells. We introduce a generic approach featuring a Lewis-acid layer sandwiched between dopant-free semicrystalline polymer and metal electrode in perovskite solar cells, resulting in an ideal quasi-ohmic contact even at elevated temperature up to 85 °C. The solubility of Lewis acid in alcohol facilitates nondestructive solution processing on top of polymer, which boosts hole injection from polymer into metal by two orders of magnitude. By integrating the polymer-acid-metal structure into solar cells, devices exhibit remarkable resilience, retaining 96% ± 3%, 96% ± 2% and 75% ± 7% of their initial efficiencies after continuous operation in nitrogen at 35 °C for 2212 h, 55 °C for 1650 h and 85 °C for 937 h, respectively. Leveraging the Arrhenius relation, we project an impressive T 80 lifetime of 26,126 h at 30 °C.