Unraveling the Dual-Functional Mechanism of Light Absorption and Hole Transport of Cu<sub>2</sub>Cd<i><sub>x</sub></i>Zn<sub>1–<i>x</i></sub>SnS<sub>4</sub> for Achieving Efficient and Stable Perovskite Solar Cells
Yanjie Wu, Wenbo Bi, Zhichong Shi, Xinmeng Zhuang, Zonglong Song, Shuainan Liu, Cong Chen, Lin Xu, Qilin Dai, Hongwei Song
Abstract
(CZTS:Cd) film prepared by thermal evaporation method was employed as the NIR light-harvesting layer to complement the absorption of the perovskite. At the same time, Au nanorods (NRs) were introduced into the hole-transporting layer (HTL) to boost the utilization of CZTS:Cd to NIR light through localized surface plasmon effect. The perovskite/CZTS:Cd and Au NR-integrated PSCs can extend the photoelectric response to 900 nm. And more, the well-matched energy levels between CZTS:Cd and perovskite can effectively extract holes from perovskite and depress the charge carrier recombination. As a result, the champion PSC device insulating with CZTS:Cd and Au NRs demonstrates a remarkably increased PCE from 19.30 to 21.11%. The modified PSC devices also demonstrate highly improved long-time stability. The device retains a PCE of 87% after 500 h even under air with a relative humidity of 85%, implying the superior humidity stability of the devices with CZTS:Cd. This work suggests that perovskite/inorganic-integrated structure is a promising strategy to broaden and boost the NIR response of the PSCs.