Achieving ordered and stable binary metal perovskite via strain engineering

Strain effects on vacancies, electronic states and stability have been disclosed for perovskite structured materials (ABX(3)) including metal oxides and organic-inorganic hybrids critical for energy storage and generation. Ion substitution has been pursued as an attractive solution to alter the crystallization or induced electronic of organic-inorganic hybrid halide lead perovskite. However, the disorganized structure of perovskite result from inappropriate substitution may cause unwanted phase transition and photo-stability. Herein, we introduce crystallization of restriction ABX(3) composition with moderate zinc (Zn) substitution to obtain the ordered and stable CH3NH3(Zn: Pb)I3-xClx crystal, which is achieved via releasing lattice strain during an appropriate lattice constriction within BX6 octahedron. We obtained an unprecedented efficiency of 20.06% under simulated sunlight with facilitating binary metal perovskite of CH3NH3(1Zn: 100Pb)I3-xClx. Our results are important to realize scale up and practical applications of efficient planar perovskite solar cells.