Stable perovskite solar cells with efficiency exceeding 24.8% and 0.3-V voltage loss.

Jeong, Mingyu; Choi, In Woo; Go, Eun Min; Cho, Yongjoon; Kim, Minjin; Lee, Byongkyu; Jeong, Seonghun; Jo, Yimhyun et al. · Science · 2020

basic_science · Level V

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Abstract

Further improvement and stabilization of perovskite solar cell (PSC) performance are essential to achieve the commercial viability of next-generation photovoltaics. Considering the benefits of fluorination to conjugated materials for energy levels, hydrophobicity, and noncovalent interactions, two fluorinated isomeric analogs of the well-known hole-transporting material (HTM) Spiro-OMeTAD are developed and used as HTMs in PSCs. The structure-property relationship induced by constitutional isomerism is investigated through experimental, atomistic, and theoretical analyses, and the fabricated PSCs feature high efficiency up to 24.82% (certified at 24.64% with 0.3-volt voltage loss), along with long-term stability in wet conditions without encapsulation (87% efficiency retention after 500 hours). We also achieve an efficiency of 22.31% in the large-area cell.