Spontaneous formation of robust two-dimensional perovskite phases
Shaun Tan, M. C. Shih, Yongli Lu, Seung‐Gu Choi, Yifan Dong, Joo‐Hong Lee, İlhan Yavuz, Bryon W. Larson, So Yeon Park, Tim Kodalle, Ruiqi Zhang, Matthias J. Grotevent, Yu‐Kuan Lin, Hua Zhu, Vladimir Bulović, Carolin M. Sutter‐Fella, Nam‐Gyu Park, Matthew C. Beard, Jin‐Wook Lee, Kai Zhu, Moungi G. Bawendi
Abstract
The two-dimensional on three-dimensional (2D/3D) perovskite bilayer heterostructure can improve the stability and performance of perovskite solar cells. We show that the 2D/3D perovskite stack in a device evolves dynamically during its end-of-life decomposition. Initially phase-pure 2D interlayers can evolve differently, resulting in different device stabilities. We show that a robust 2D interlayer can be formed using mixed solvents to regulate its crystallinity and phase purity. The resulting 2D/3D devices achieved 25.9% efficiency and had good durability, retaining 91% of their initial performance after 1074 hours at 85°C using maximum power point tracking.