Incorporation of Nickel Ions to Enhance Integrity and Stability of Perovskite Crystal Lattice for High-Performance Planar Heterojunction Solar Cells

摘要： Enhancement of integrity and stability of crystal lattice are highly challenging for poly-crystalline perovskite films. In this work, a nickel (Ni) ions incorporation strategy is presented to modulate the crystal structure of CH3NH3PbI3 perovskite film. A broad range of experimental characterizations reveal that the incorporation of Ni ions can substantially eliminate the intrinsic halide vacancy defects since Ni ions have a strong preference for octahedral coordination with halide ions, resulting in improved integrity and short-range order of crystal lattice significantly. Moreover, it is also demonstrated that the stronger chemical bonding interaction between Ni ions and halide ions as well as organic group can improve the stability of perovskite material. Simultaneously, the surface morphology of perovskite thin film is also improved by incorporation of nickel ions. As a result, the 1.5% Ni-incorporated planar heterojunction perovskite solar cell exhibits a power conversion efficiency of 18.82%, which is improved by 25% compared with 14.92% for the pristine device. Simultaneously, the 1.5% Ni- incorporated device shows remarkable stability with 90% of the initial efficiency after storage in air environment for 800 h. The studies provide a new insight for metal-incorporated perovskite materials for various optoelectronic applications.