Spontaneously Self‐Assembly of a 2D/3D Heterostructure Enhances the Efficiency and Stability in Printed Perovskite Solar Cells
Jinlong Hu, Chuan Wang, Shudi Qiu, Yicheng Zhao, Ening Gu, Linxiang Zeng, Yuzhao Yang, Chaohui Li, Xianhu Liu, Karen Forberich, Christoph J. Brabec, Mohammad Khaja Nazeeruddin, Yaohua Mai, Fei Guo
Abstract
Abstract As perovskite solar cells (PSCs) are highly efficient, demonstration of high‐performance printed devices becomes important. 2D/3D heterostructures have recently emerged as an attractive way to relieving the film inhomogeneity and instability in perovskite devices. In this work, a 2D/3D ensemble with 2D perovskites self‐assembled atop 3D methylammonium lead triiodide (MAPbI 3 ) via a one‐step printing process is shown. A clean and flat interface is observed in the 2D/3D bilayer heterostructure for the first time. The 2D perovskite capping layer significantly suppresses nonradiative charge recombination, resulting in a marked increase in open‐circuit voltage ( V OC ) of the devices by up to 100 mV. An ultrahigh V OC of 1.20 V is achieved for MAPbI 3 PSCs, corresponding to 91% of the Shockley–Queisser limit. Moreover, notable enhancement in light, thermal, and moisture stability is obtained as a result of the protective barrier of the 2D perovskites. These results suggest a viable approach for scalable fabrication of highly efficient perovskite solar cells with enhanced environmental stability.