Manipulating the Formation of 2D/3D Heterostructure in Stable High-Performance Ambient-Printed CsPbI3 Perovskite Solar Cells

    Abstract

    Manipulating the formation process of the 2D/3D perovskite heterostructure, including its nucleation/growth dynamics and phase transition pathway, plays a critical role in controlling the charge transport between 2D and 3D crystals, and consequently, the scalable fabrication of efficient and stable perovskite solar cells. In this study, we demonstrated the fabrication of a 2D/3D layered structure for stable and high-performance ambient-printed CsPbI3 solar cells based on a series of organic ligands. Using time-resolved X-ray diffraction, the structural evolution and phase transition pathways of the ligand-dependent 2D perovskite atop the 3D surface were revealed. The results show that the ligand size has a critical influence on the final 2D structure. In particular, ligands with smaller sizes tend to form the n=1 phase. Increasing the ligand size promoted the transformation from 3D to n=3 and n<3 phases. These findings are useful for the rational design of the phase distribution in 2D perovskites to balance the charge transport at the heterostructure and stability of the perovskite films. Finally, ambient-printed CsPbI3 solar cells with n-butylammonium iodide treatment achieved an improved efficiency of 20.33%, which is the highest reported value for printed all-inorganic perovskite solar cells. Furthermore, the significant enhancement of the device stability is a notable feature of these ambient-printed 2D/3D CsPbI3 solar cells.

https://onlinelibrary.wiley.com/doi/10.1002/adma.202206451