Lead‐based double perovskites are studied in the cubic phase using the generalized gradient approximation and the modified Becke–Johnson (mBJ‐GGA) functionals as implemented in the Wien2K code. Goldschmidt tolerance factor and octahedral factor, formation enthalpy, and formation energy translate the structural, chemical, and thermodynamic stability of double perovskites studied. Phonon band structures and elastic moduli ensure the dynamic and mechanical stability of (Cs2, K2, Rb2)PbCl6. An intermediate band appears in the conduction band and the fundamental transition takes place between 3p‐Cl state and 6p‐Pb site. The refractive index of double perovskites (Cs2, K2, Rb2)PbCl6 in the visible and ultraviolet light hold a huge advantage for solar cell applications. The wide dielectric constant of double perovskites under study makes them capable for absorbing energy between 1 and 5 eV, and are suitable for solar power applications. (Cs2, K2, Rb2)PbCl6 have positive Seebeck coefficient, which reveals that p‐type charge carriers are dominant for enhancing their performance. Cs2PbCl6 has positive thermal conductivity for both n‐type and p‐type character. (K2, Rb2)PbCl6 have positive thermal conductivity for n‐type character. The complete analysis reveals that they are potentially significant candidates for future solar cells and energy harvesting devices.

中文翻译：

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对 （Cs2， K2， Rb2）PbCl6 铅基双钙钛矿稳定性、力学、光电和热电特性研究的计算见解：光电应用的有前途的候选者


使用广义梯度近似和在 Wien2K 代码中实现的改进的 Becke-Johnson （mBJ-GGA） 泛函在立方相中研究铅基双钙钛矿。Goldschmidt 容差因子和八面体因子、形成焓和形成能转化为所研究的双钙钛矿的结构、化学和热力学稳定性。声子带结构和弹性模量保证了 （Cs2， K2， Rb2）PbCl6 的动态和机械稳定性。导带中出现一个中间带，基本转变发生在 3p-Cl 状态和 6p-Pb 位点之间。双钙钛矿 （Cs2， K2， Rb2） PbCl6 在可见光和紫外光下的折射率在太阳能电池应用中具有巨大的优势。正在研究的双钙钛矿的宽介电常数使其能够吸收 1 至 5 eV 的能量，适用于太阳能应用。（Cs2、K2、Rb2）PbCl6 具有正塞贝克系数，这表明 p 型电荷载流子在增强其性能方面占主导地位。Cs2PbCl6 的 n 型和 p 型特性均具有正热导率。（K2，Rb2）PbCl6 具有 n 型特性的正导热性。完整的分析表明，它们可能是未来太阳能电池和能量收集设备的重要候选者。