Gill Deepika, Singh Arunima, Jain Manjari, Bhattacharya Saswata
Department of Physics, Indian Institute of Technology Delhi, New Delhi, Delhi 110016, India.
J Phys Chem Lett. 2021 Jul 22;12(28):6698-6706. doi: 10.1021/acs.jpclett.1c01486. Epub 2021 Jul 14.
Ruddlesden-Popper (RP) phases of BaZrS are an evolving class of chalcogenide perovskites in the field of optoelectronics, especially in solar cells. However, detailed studies regarding its optical, excitonic, polaronic, and transport properties are hitherto unknown. Here, we have explored the excitonic and polaronic effect using several first-principles based methodologies under the framework of Many Body Perturbation Theory. Unlike its bulk counterpart, the optical and excitonic anisotropy are observed in BaZrS ( = 1-3) RP phases. As per the Wannier-Mott approach, the ionic contribution to the dielectric constant is important, but it gets decreased on increasing in BaZrS. The exciton binding energy is found to be dependent on the presence of large electron-phonon coupling. We further observed maximum charge carrier mobility in the BaZrS phase. As per our analysis, the optical phonon modes are observed to dominate the acoustic phonon modes, leading to a decrease in polaron mobility on increasing in BaZrS ( = 1-3).
BaZrS的Ruddlesden-Popper（RP）相是光电子学领域中一类不断发展的硫族钙钛矿，特别是在太阳能电池方面。然而，关于其光学、激子、极化子和输运性质的详细研究迄今尚不清楚。在此，我们在多体微扰理论框架下，使用几种基于第一性原理的方法探索了激子和极化子效应。与体相不同，在BaZrS（n = 1 - 3）的RP相中观察到了光学和激子各向异性。根据Wannier-Mott方法，离子对介电常数的贡献很重要，但在BaZrS中随着n的增加而减小。发现激子结合能取决于大的电子-声子耦合的存在。我们进一步观察到BaZrS相中的最大电荷载流子迁移率。根据我们的分析，观察到光学声子模式主导声学声子模式，导致在BaZrS（n = 1 - 3）中随着n的增加极化子迁移率降低。
