Interlayer coupling prolonged the photogenerated carrier lifetime of few layered BiOS semiconductors

• Published in: Nanoscale 2020-03, Vol.12 (1), p.657-663
• Main Authors: Niu, Xianghong, Wu, Guangfen, Zhang, Xiwen, Wang, Jinlan
• Format: Article
• Language: English
• ISSN: 2040-3364; 2040-3372
• DOI: 10.1039/d0nr00447b

Layered semiconductors with broad photoabsorption, a long carrier lifetime and high carrier mobility are of crucial importance for high-performance optoelectronic and photovoltaic devices; however it is hard to satisfy these requirements simultaneously in a system due to the opposite dependence on the layer thickness. Herein, by means of ab initio time-domain nonadiabatic molecular dynamic simulations, we find a new mechanism in Bi 2 OS 2 nanosheets inducing an anomalous layer-dependent property of carrier lifetimes, which makes the few layered Bi 2 OS 2 a possible system for fulfilling the above requirements concurrently. It is revealed that the interlayer dipole-dipole interaction in few layered Bi 2 OS 2 effectively breaks the two-fold degenerate orbitals of [BiS 2 ] layers, which not only cuts down the overlap of the electron and hole wave functions, but also accelerates the electron decoherence process. This significantly suppresses the electron-hole recombination and prolongs the photogenerated carrier lifetime of few layered Bi 2 OS 2 . The mechanism unveiled here paves a possible way for developing advanced optoelectronic and photovoltaic devices through engineering interlayer dipole-dipole coupling. Interlayer coupling inducing an anomalous layer number dependent property of carrier lifetimes in Bi 2 OS 2 nanosheet.