Roknuzzaman Md, Ostrikov Kostya Ken, Wang Hongxia, Du Aijun, Tesfamichael Tuquabo
School of Chemistry, Physics and Mechanical Engineering and Institute of Future Environments, Queensland University of Technology, QLD 4000, Brisbane, Australia.
Sci Rep. 2017 Oct 25;7(1):14025. doi: 10.1038/s41598-017-13172-y.
Lead (Pb) free non-toxic perovskite solar cells have become more important in the commercialization of the photovoltaic devices. In this study the structural, electronic, optical and mechanical properties of Pb-free inorganic metal halide cubic perovskites CsBX (B = Sn, Ge; X = I, Br, Cl) for perovskite solar cells are simulated using first-principles Density Functional Theory (DFT). These compounds are semiconductors with direct band gap energy and mechanically stable. Results suggest that the materials have high absorption coefficient, low reflectivity and high optical conductivity with potential application in solar cells and other optoelectronic energy devices. On the basis of the optical properties, one can expect that the Germanium (Ge) would be a better replacement of Pb as Ge containing compounds have higher optical absorption and optical conductivity than that of Pb containing compounds. A combinational analysis of the electronic, optical and mechanical properties of the compounds suggests that CsGeI based perovskite is the best Pb-free inorganic metal halide semiconductor for the solar cell application. However, the compound with solid solution of CsGe(IBr) is found to be mechanically more ductile than CsGeI. This study will also guide to obtain Pb-free organic perovskites for optoelectronic devices.
无铅无毒钙钛矿太阳能电池在光伏器件商业化中变得愈发重要。在本研究中，使用第一性原理密度泛函理论（DFT）模拟了用于钙钛矿太阳能电池的无铅无机金属卤化物立方钙钛矿CsBX（B = Sn，Ge；X = I，Br，Cl）的结构、电子、光学和力学性能。这些化合物是具有直接带隙能量的半导体且力学稳定。结果表明，这些材料具有高吸收系数、低反射率和高光学电导率，在太阳能电池及其他光电器件中具有潜在应用价值。基于光学性能，由于含锗化合物比含铅化合物具有更高的光吸收和光学电导率，可以预期锗将是铅的更好替代物。对这些化合物的电子、光学和力学性能进行的综合分析表明，基于CsGeI的钙钛矿是太阳能电池应用中最佳的无铅无机金属卤化物半导体。然而，发现具有CsGe(IBr)固溶体的化合物在力学上比CsGeI更具延展性。本研究还将为获得用于光电器件的无铅有机钙钛矿提供指导。
