Abstract We investigate the structural, electronic and optical properties of lead-free halide Cs2TiI6 halide perovskites using ab-initio calculations. It is shown that the Ti-based halide perovskites possess several interesting properties, including high stability, suitable bandgap, and excellent optical absorption. It is demonstrated that the Cs2TiI6 compound presents a bandgap energy value of 0.998 eV. The absorption coefficient is in the order of 105 cm−1, these properties make Cs2TiI6 halide perovskites a good candidate for photovoltaic applications. In addition, the effect of pressure on the electronic properties were studied, in which we demonstrate that the bandgap energy depend significantly on the applied pressure.

中文翻译：

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无铅卤化物Cs2TiI6双钙钛矿的结构、电子和光学性质的从头算研究

摘要 我们使用 ab-initio 计算研究了无铅卤化物 Cs2TiI6 卤化物钙钛矿的结构、电子和光学特性。结果表明，钛基卤化物钙钛矿具有几个有趣的特性，包括高稳定性、合适的带隙和优异的光吸收。结果表明，Cs2TiI6 化合物的带隙能量值为 0.998 eV。吸收系数约为 105 cm-1，这些特性使 Cs2TiI6 卤化物钙钛矿成为光伏应用的良好候选者。此外，研究了压力对电子特性的影响，其中我们证明了带隙能量显着依赖于施加的压力。