In situ energetics modulation enables high-efficiency and stable inverted perovskite solar cells

In contrast to conventional (n-i-p) perovskite solar cells (PSCs), inverted (p-i-n) PSCs offer enhanced stability and integrability with tandem solar cell architectures, which have garnered increasing interest. However, p-i-n cells suffer from energy level misalignment with transport layers, imbalanced transport of photo-generated electrons and holes, and significant defects with the perovskite films. Here we introduce tris(2,4,6-trimethyl-3-(pyridin-3-yl)phenyl)borane (3TPYMB), a nonionic n-type molecule that, through hydrogen bonding and Lewis acid-base reactions with perovskite surfaces or grain boundaries, enables in situ modulation of perovskite energetics, effectively mitigating the key challenges of p-i-n PSCs. The p-i-n PSCs incorporating 3TPYMB achieve a certified quasi-steady-state power conversion efficiency of 24.55 +- 0.33%, with a reverse scan efficiency of 25.58%. Finally, they also exhibit exceptional stability, with unencapsulated devices retaining 97.8% of their initial efficiency after 1,800 h of continuous operation at maximum power point under N₂ atmosphere, 1 sun illumination and 60 °C conditions.. Authors: Zhu, Hongwei [King Abdullah University of Science and Technology (KAUST), Thuwal (Saudi Arabia)] (ORCID:0000000227415172); Shao, Bingyao [King Abdullah University of Science and Technology (KAUST), Thuwal (Saudi Arabia)] (ORCID:0000000293343592); Shen, Zhongjin [Newcastle University, Newcastle upon Tyne (United Kingdom)] (ORCID:0000000314548061); You, Shuai [National Renewable Energy Laboratory (NREL), Golden, CO (United States)] (ORCID:0000000310071446); Yin, Jun [King Abdullah University of Science and Technology (KAUST), Thuwal (Saudi Arabia)] (ORCID:0000000217491120). DOE Contract: AC36-08GO28308. Subjects: 14 SOLAR ENERGY; defect passivation; interfacial energetics; inverted device structure; perovskite; solar cells