Dipolar cations confer defect tolerance in wide-bandgap metal halide perovskites

作者：Tan, Hairen^*; Che, Fanglin; Wei, Mingyang; Zhao, Yicheng; Saidaminov, Makhsud, I; Todorovic, Petar; Broberg, Danny; Walters, Grant; Tan, Furui; Zhuang, Taotao; Sun, Bin; Liang, Zhiqin; Yuan, Haifeng; Fron, Eduard; Kim, Junghwan; Yang, Zhenyu; Voznyy, Oleksandr; Asta, Mark; Sargent, Edward H.^*

来源：Nature Communications, 2018, 9(1): 3100.

DOI：10.1038/s41467-018-05531-8

• TANDEM SOLAR-CELLS
• TOTAL-ENERGY CALCULATIONS
• MOLECULAR-DYNAMICS
• HIGH-PERFORMANCE
• EFFICIENT
• LIFETIMES
• CARRIERS
• ORIGIN
• FILMS

Efficient wide-bandgap perovskite solar cells (PSCs) enable high-efficiency tandem photo-voltaics when combined with crystalline silicon and other low-bandgap absorbers. However, wide-bandgap PSCs today exhibit performance far inferior to that of sub-1.6-eV bandgap PSCs due to their tendency to form a high density of deep traps. Here, we show that healing the deep traps in wide-bandgap perovskites-in effect, increasing the defect tolerance via cation engineering-enables further performance improvements in PSCs. We achieve a stabilized power conversion efficiency of 20.7% for 1.65-eV bandgap PSCs by incorporating dipolar cations, with a high open-circuit voltage of 1.22 V and a fill factor exceeding 80%. We also obtain a stabilized efficiency of 19.1% for 1.74-eV bandgap PSCs with a high open-circuit voltage of 1.25 V. From density functional theory calculations, we find that the presence and reorientation of the dipolar cation in mixed cation-halide perovskites heals the defects that introduce deep trap states.

• 出版日期2018-8-6
• 单位河南大学; 南京大学