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 (MAPbI(3)) perovskite. In this report, we successfully fabricate tetragonal (200) oriented MAPbI(3) films by carefully screening hot casting (HC) temperature and processing solvent. Compared to tetragonal (110) oriented MAPbI(3) 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 MAPbI(3) 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 MAPbI(3) devices. This work highlights the potential of tetragonal (200) oriented MAPbI(3) film for photovoltaic applications and may inspire more studies on the manipulation of perovskite crystal orientation.

Automated summary

This study successfully fabricated tetragonal (200) oriented MAPbI(3) films and compared them with traditional (110) oriented films. The results showed that tetragonal (200) oriented films had larger crystal grain size, lower trap density, and better charge transfer properties. MAPbI(3) PSCs based on tetragonal (200) oriented films achieved a record efficiency of 20.22%.