Vacancy-ordered double perovskites have attracted broad attention due to the thermostability and excellent optoelectronic properties. Here, we report first-principles investigations on optoelectronic properties of a series of ns²-containing vacancy-ordered double perovskites by substituting monovalent Cs with divalent Ba. These perovskites are predicted to show indirect bandgaps similar to the bismuth-based double perovskites. Unlike the regular metal halide perovskites, the 6s orbital of A-site Ba cation in these ns²-containing compounds composes lower conduction bands, and calculated dipole matrix elements demonstrate the influence of A-site Ba 6s-orbital on the optical absorption. Moreover, decomposition energies, electronic bandgaps, and effective masses of holes and electrons are calculated to assess the potential optoelectronic application, which could be a theoretical guide for exploring novel lead-free perovskite materials.

由于热稳定性和优异的光电性能，空位有序双钙钛矿引起了广泛的关注。在这里，我们通过用二价 Ba 取代单价 Cs ，报告了对一系列含ns ²空位有序双钙钛矿的光电特性的第一性原理研究。预计这些钙钛矿将显示类似于基于铋的双钙钛矿的间接带隙。与常规金属卤化物钙钛矿不同，这些含ns ²化合物中A位 Ba 阳离子的 6 s轨道构成较低的导带，计算的偶极矩阵元素证明了A位 Ba 6 s 的影响-轨道上的光吸收。此外，还计算了分解能、电子带隙以及空穴和电子的有效质量，以评估潜在的光电应用，这可能为探索新型无铅钙钛矿材料提供理论指导。