Unraveling the Dual-Functional Mechanism of Light Absorption and Hole Transport of Cu 2 Cd x Zn 1- x SnS 4 for Achieving Efficient and Stable Perovskite Solar Cells

• Published in: ACS applied materials & interfaces 2020-04, Vol.12 (15), p.17509-17518
• Main Authors: Wu, Yanjie, Bi, Wenbo, Shi, Zhichong, Zhuang, Xinmeng, Song, Zonglong, Liu, Shuainan, Chen, Cong, Xu, Lin, Dai, Qilin, Song, Hongwei
• Format: Article
• Language: English
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.0c00607

Broadening the near-infrared (NIR) spectrum of device is critical to further improve the power conversion efficiency (PCE) of the perovskite solar cells (PSCs). In this work, novel Cu CdZn SnS (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.