@article{oai:oist.repo.nii.ac.jp:00002890,
 author = {Wu, Tianhao and Ono, Luis K. and Yoshioka, Rengo and Ding, Chenfeng and Zhang, Congyang and Mariotti, Silvia and Zhang, Jiahao and Mitrofanov, Kirill and Liu, Xiao and Segawa, Hiroshi and Kabe, Ryota and Han, Liyuan and Qi, Yabing},
 issue = {11},
 journal = {Energy & Environmental Science},
 month = {Sep},
 note = {Nickel oxide (NiOx) is a promising hole-selective contact to produce efficient inverted p-i-n structured perovskite solar cells (PSCs) due to its high carrier mobility and high transparency. However, the light-induced degradation of the NiOx–perovskite heterojunction is the main factor limiting its long-term operational lifetime. In this study, we used the time-resolved mass spectrometry technique to clarify the degradation mechanism of the NiOx-formamidinium–methylammonium iodide perovskite (a common composition for high-performance PSCs) heterojunction under operational conditions, and observed that (1) oxidation of iodide and generation of free protons under 1-sun illumination, (2) formation of volatile hydrogen cyanide, methyliodide, and ammonia at elevated temperatures, and (3) a condensation reaction between the organic components under a high vapor pressure. To eliminate these multi-step photochemical reactions, we constructed an aprotic trimethylsulfonium bromide (TMSBr) buffer layer at the NiOx/perovskite interface, which enables excellent photo-thermal stability, a matched lattice parameter with the perovskite crystal, and robust trap-passivation ability. Inverted PSCs stabilized with the TMSBr buffer layer reached the maximum efficiency of 22.1% and retained 82.8% of the initial value after continuous operation for 2000 hours under AM1.5G light illumination, which translates into a T80 lifetime of 2310 hours that is among the highest operational lifetimes for NiOx-based PSCs.},
 pages = {4612--4624},
 title = {Elimination of light-induced degradation at the nickel oxide-perovskite heterojunction by aprotic sulfonium layers towards long-term operationally stable inverted perovskite solar cells},
 volume = {15},
 year = {2022}
}