Kagdada Hardik L, Gupta Sanjeev K, Sahoo Satyaprakash, Singh Dheeraj K
Department of Physics, Institute of Infrastructure Technology Research and Management (IITRAM), Ahmedabad 380026, India.
Computational Materials and Nanoscience Group, Department of Physics, St. Xavier's College, Ahmedabad 380009, India.
J Phys Chem Lett. 2020 Sep 17;11(18):7679-7686. doi: 10.1021/acs.jpclett.0c01858. Epub 2020 Aug 31.
The physical properties of two-dimensional (2D) lead halide based hybrid perovskites are quite exciting and challenging. Further, the role of organic cations in 2D perovskites is still in a debate. We investigated layered (CH(CH)NH)(CHNH)PbI 2D Ruddlesden-Popper (2DRP) phase (M1) and 2D derivative of CHNHPbI (M2) using density functional theory. The spin orbit coupling mediates the significantly large Rashba splitting energy of 328.5 meV for M2, which is higher than earlier 2D hybrid perovskites. At the picosecond time scale, the dynamical Rashba effect was observed due to organic and inorganic cation dynamics. Two step absorption suggests an indirect optical gap of 2.38 and 2.15 eV for M1 and M2, respectively and solar performance depicts excellent power conversion efficiency of 14.92% and 19.75% for M1 and M2, respectively. For the first time, we explored the thermoelectric properties of 2D hybrid perovskites and perceived high power factor for p-type doping in M2. Our findings suggest that these novel 2D perovskites have the potential to be used in solar and heat energy harvesting.
二维（2D）卤化铅基杂化钙钛矿的物理性质十分令人兴奋且具有挑战性。此外，有机阳离子在二维钙钛矿中的作用仍存在争议。我们使用密度泛函理论研究了层状（CH(CH)NH)(CHNH)PbI二维Ruddlesden-Popper（2DRP）相（M1）和CHNHPbI的二维衍生物（M2）。自旋轨道耦合介导了M2的显著大的Rashba分裂能，为328.5毫电子伏特，高于早期的二维杂化钙钛矿。在皮秒时间尺度上，由于有机和无机阳离子动力学，观察到了动态Rashba效应。两步吸收表明M1和M2的间接光学带隙分别为2.38和2.15电子伏特，太阳能性能表明M1和M2的功率转换效率分别为14.92%和19.75%，表现优异。我们首次探索了二维杂化钙钛矿的热电性质，并发现M2中p型掺杂具有高功率因子。我们的研究结果表明，这些新型二维钙钛矿有潜力用于太阳能和热能收集。
