The Recent development of halide double perovskites A2M+M3+X6 has attracted attention as potential lead-free perovskites solar cell absorbers. Here, the stability, electronic, and optical properties of the lead-free inorganic-organic hybrid double perovskites (CH3NH3)2InBiX6 (X = halogen) are studied based on density functional theory. By investigating the thermodynamic stability against decomposition, the (CH3NH3)2InBiX6 double perovskites are shown to be stable. Furthermore, the use of a small magnitude of hydrostatic pressure is proposed to improve the thermodynamic stability of double perovskites (CH3NH3)2InBiX6. Meanwhile, the calculated electronic band structures of (CH3NH3)2InBiX6 double perovskites exhibit suitable direct band gaps, small carrier effective masses, and 3D electronic dimensionality. This, in turn, leads to strong optical absorption. Both the electronic and optical features make double perovskites (CH3NH3)2InBiX6 suitable for applications in optoelectronics.

中文翻译：

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无铅卤化物双钙钛矿（CH3NH3）2InBiX6（X =卤素）的稳定性，电子和光学性质

作为潜在的无铅钙钛矿太阳能电池吸收剂，卤化物双钙钛矿A2M + M3 + X6的最新发展引起了人们的关注。在此，基于密度泛函理论研究了无铅无机-有机杂化双钙钛矿（CH3NH3）2InBiX6（X =卤素）的稳定性，电子和光学性质。通过研究抗分解的热力学稳定性，显示了（CH3NH3）2InBiX6双钙钛矿是稳定的。此外，建议使用较小的静水压力来提高双钙钛矿（CH3NH3）2InBiX6的热力学稳定性。同时，计算得到的（CH3NH3）2InBiX6双钙钛矿的电子能带结构表现出合适的直接带隙，较小的载流子有效质量和3D电子尺寸。反过来，导致强烈的光吸收。电子和光学特性均使钙钛矿（CH3NH3）2InBiX6成为适用于光电子学的材料。