Highly efficient (200) oriented MAPbI3 perovskite solar cells

Although perovskite composition, film-processing technology, and interface engineering have been widely studied to boost efficiencies of perovskite solar cells (PSCs), the crystal orientation which considerably influences the charge transfer properties of perovskite is rarely mentioned for the classic (CH3NH3)PbI3 (MAPbI3) perovskite. In this report, we successfully fabricate tetragonal (200) oriented MAPbI3 films by carefully screening hot-casting (HC) temperature and processing solvent. Compared to tetragonal (110) oriented MAPbI3 films prepared from traditional post-annealing (PA) method, the (200) analogues are composed of much larger crystal grains up to hundreds of microns, with lower trap density and higher charge transfer property. The corresponding MAPbI3 PSCs afford a record efficiency of 20.22% among devices based on the (200) oriented film, much higher than that obtained from the (110) oriented MAPbI3 devices. This work highlights the potential of tetragonal (200) oriented MAPbI3 film for photovoltaic applications and may inspire more studies on the manipulation of perovskite crystal orientation.