Umadevi Deivasigamani, Watson Graeme W
School of Chemistry and CRANN, Trinity College Dublin, The University of Dublin, Dublin D2, Ireland.
ACS Omega. 2019 Mar 21;4(3):5661-5669. doi: 10.1021/acsomega.8b03291. eCollection 2019 Mar 31.
Lead-free organic-inorganic halide perovskites have gained much attention as nontoxic alternatives to CHNHPbI in next-generation solar cells. In this study, we have examined the geometric and electronic properties of methylammonium germanium iodide CHNHGeI using density functional theory. Identifying a suitable functional to accurately model the germanium halide perovskites is crucial to allow the theoretical investigation for tuning the optoelectronic properties. The performance of various functionals (PBE, PBE+D3, PBEsol, PBEsol+D3, HSE06, and HSE06+D3) has been evaluated for modelling the structure and properties. The calculation of electronic properties was further refined by using the quasiparticle method on the optimized geometries, and that has an excellent agreement with the experiment. We report from our calculations that the characteristic of the density of states for CHNHGeI resembles the density of states for CHNHPbI and the effective masses of the charge carriers of CHNHGeI are comparable to the effective masses of CHNHPbI as well as silicon used in commercially available solar cells.
无铅有机-无机卤化物钙钛矿作为下一代太阳能电池中CH₃NH₃PbI₃的无毒替代品受到了广泛关注。在本研究中，我们使用密度泛函理论研究了碘化甲铵锗（CH₃NH₃GeI₃）的几何和电子性质。确定一种合适的泛函来准确模拟锗卤化物钙钛矿对于进行调整光电性质的理论研究至关重要。已评估了各种泛函（PBE、PBE+D3、PBEsol、PBEsol+D3、HSE06和HSE06+D3）在模拟结构和性质方面的性能。通过在优化几何结构上使用准粒子方法进一步完善了电子性质的计算，并且与实验结果具有很好的一致性。我们从计算中报告，CH₃NH₃GeI₃的态密度特征类似于CH₃NH₃PbI₃的态密度，并且CH₃NH₃GeI₃的电荷载流子有效质量与CH₃NH₃PbI₃以及市售太阳能电池中使用的硅的有效质量相当。
