Interfacial Strain Release from the WS2/CsPbBr3 van der Waals Heterostructure for 1.7 V Voltage All‐Inorganic Perovskite Solar Cells.

Perovskite lattice distortion induced by residual tensile strain from the thermal expansion mismatch between the electron‐transporting layer (ETL) and perovskite film causes a sluggish charge extraction and transfer dynamics in all‐inorganic CsPbBr3 perovskite solar cells (PSCs) because of their higher crystallization temperatures and thermal expansion coefficients. Herein, the interfacial strain is released by fabricating a WS2/CsPbBr3 van der Waals heterostructure owing to their matched crystal lattice structure and the atomically smooth dangling bond‐free surface to act as a lubricant between ETL and CsPbBr3 perovskite. Arising from the strain‐released interface and condensed perovskite lattice, the best device achieves an efficiency of 10.65 % with an ultrahigh open‐circuit voltage of 1.70 V and significantly improved stability under persistent light irradiation and humidity (80 %) attack over 120 days. [ABSTRACT FROM AUTHOR]