Dipolar cations confer defect tolerance in wide-bandgap metal halide perovskites
Abstract
Efficient wide-bandgap perovskite solar cells (PSCs) enable high-efficiency tandem photovoltaics 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.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Aug 06, 2018
- Source ID
- 10.1038/s41467-018-05531-8
Entities
People
- Bin Sun
- Danny Broberg
- Eduard Fron
- Edward H. Sargent
- Fanglin Che
- Furui Tan
- Grant Walters
- Haifeng Yuan
- Hairen Tan
- Junghwan Kim
- Makhsud I Saidaminov
- Mark Asta
- Mingyang Wei
- Oleksandr Voznyy
- Petar Todorović
- Taotao Zhuang
- Yicheng Zhao
- Zhenyu Yang
- Zhiqin Liang