Efficient and stable Cs2AgBiBr6 double perovskite solar cells through in-situ surface modulation

作者：Li, Bo; Wu, Xin; Zhang, Shoufeng; Li, Zhen; Gao, Danpeng; Chen, Xiankai; Xiao, Shuang; Chueh, Chu-Chen; Zhu, Zonglong^*

来源：Chemical Engineering Journal, 2022, 446: 137144.

DOI：10.1016/j.cej.2022.137144

• Double perovskite solar cells
• Cs 2 AgBiBr 6
• Defect passivation
• Fused-ring electron acceptor
• High efficiency

Lead-free double perovskites have drawn increasing attention for addressing the stability and toxicity challenges from lead-based halide perovskites. However, their power conversion efficiencies (PCE) are still far behind that of Pb-based perovskite solar cells (PSCs) mainly because of the severe energy loss. Herein, we successfully employed the fused-ring electron acceptor (FREA) molecules to passivate defects in Cs2AgBiBr6-based double PSCs to realize a dramatically enhanced open-circuit voltage (VOC) from 1.079 V to 1.278 V and a champion PCE up to 3.31%, which is the highest efficiency for double PSCs to date. The strong binding of C equivalent to N and N=C-S groups on FREA with Ag-exposed surface of Cs2AgBiBr6 effectively decreased surface trap densities and considerably suppressed non-radiative recombination. Moreover, the passivated devices showed superior longterm stability, which maintained 98.5% and 97.2% of the initial efficiency under continuous AM 1.5 G illumination and 85 celcius heating for 300 h, respectively. This work manifests the importance of the rational design of functional passivation molecules to improve the performance and stability of double PSCs.

• 单位
  北京大学