Multiple Roles of Cobalt Pyrazol-Pyridine Complexes in High-Performing Perovskite Solar Cells

Jianfeng Lu, Andrew D. Scully, Jingsong Sun, Boer Tan, Anthony S.R. Chesman, Sonia Ruiz Raga, Liangcong Jiang, Xiongfeng Lin, Narendra Pai, Wenchao Huang, Yi Bing Cheng, Udo Bach, Alexandr N. Simonov

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12 Citations (Scopus)


Chemical doping is a ubiquitously applied strategy to improve the charge-transfer and conductivity characteristics of spiro-OMeTAD, a hole-transporting material (HTM) used widely in solution-processed perovskite solar cells (PSCs). Cobalt(III) complexes are commonly employed HTM dopants, whose major role is to oxidize spiro-OMeTAD to provide p-doping for improved conductivity. The present work discloses additional, previously unknown important functions of cobalt complexes in the HTM films that influence the photovoltaic performance. Specifically, it is demonstrated that commercial p-dopant FK269 (bis(2,6-di(1H-pyrazol-1-yl)pyridine) cobalt(III) tris(bis(trifluoromethylsulfonyl)imide)) reduces the interfacial recombination and alleviates the decomposition of the perovskite layer under the action of tert-butylpyridine and lithium bis(trifluoromethanesulfonyl)imide. These effects are demonstrated for 1 cm2 perovskite solar cells that achieve a stabilized power conversion efficiency of 19% under 1 sun irradiation.

Original languageEnglish
Pages (from-to)4675-4682
Number of pages8
JournalJournal of Physical Chemistry Letters
Issue number16
Publication statusPublished - 21 Jul 2019

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