摘要：SummaryPotential multijunction application of CsPbI3perovskite with silicon solar cells to reach efficiencies beyond the Shockley-Queisser limit motivates tremendous efforts to improve its phase stability and further enlarge its band gap between 1.7 and 1.8 eV. Current strategies to increase band gap via conventional mixed halide engineering are accompanied by detrimental phase segregation under illumination. Here, ethylammonium (EA) in a relatively small fraction (x < 0.15) is first investigated to fit into three-dimensional CsPbI3framework to form pure-phase hybrid perovskites with enlarged band gap over 1.7 eV. The increase of band gap is closely associated with the distortion of Pb-I octahedra and the variation of the average Pb-I-Pb angle. Meanwhile, the introduction of EA can retard the crystallization of perovskite and tune the perovskite structure with enhanced phase stability and transport properties.Graphical abstractDisplay OmittedHighlights•Perspectives of applying structural distortion to improve the band gap•Perovskites with high band gap over 1.7 eV for potential multijunction application•Enhancing phase stability and transport property without instinct phase separation•The introduction of organic cation of EA with the optimum amount below 0.15Chemistry; Quantum Chemistry; Quantum Optics; Engineering
