The structural, electronic, and optical properties of organic-inorganic mixed halide perovskites CH3NH3Pb(I1-yXy)3 (X ＝ Cl, Br)

• 来源期刊: 中国物理B（英文版）
• 关键词: density functional theory organic-inorganic perovskite doping absorption efficiency
• 年，卷（期）: 2018,（6）
• 页码范围: 357-366
• 页数: 10页
• 语种: 英文
• DOI: 10.1088/1674-1056/27/6/067102

摘要

Methylammmonium lead iodide perovskites (CH3NH3PbI3) have received wide attention due to their superior optoelectronic properties.We performed first-principles calculations to investigate the structural,electronic,and optical properties of mixed halide perovskites CH3NH3Pb(I1-yXy)3 (X =CI,Br;y =0,0.33,0.67).Our results reveal the reduction of the lattice constants and dielectric constants and enhancement of band gaps with increasing doping concentration of C1-/Br-at I-.Electronic structure calculations indicate that the valance band maximum (VBM) is mainly governed by the halide p orbitals and Pb 6s orbitals,Pb 6p orbitals contribute the conduction band minimum (CBM) and doping does not change the direct semiconductor material.The organic cation [CH3NH3]+ does not take part in the formation of the band and only one electron donates to the considered materials.The increasing trends of the band gap with C1 content from y =0 (0.793 eV) to y =0.33 (0.953 eV) then to y =0.67 (1.126 eV).The optical absorption of the considered structures in the visible spectrum range is decreased but after doping the stability of the material is improving.