Role of defects in ultrafast charge recombination in monolayer MoS2

In this paper, we have systematically studied the role of point defects in the recombination time of monolayer MoS2 using time-dependent ab initio nonadiabatic molecular dynamics simulations. Various types of point defects, such as S vacancy, S interstitial, Mo vacancy, and Mo interstitial have been considered. We show that defects strongly accelerate the electron-hole recombination, especially interstitial S atoms do that by three orders of magnitude higher compared to pristine MoS2. Mo defects (both vacancy and interstitial) introduce a multitude of de-excitation pathways via various defect levels in the energy gap. The results of this study provide some fundamental understanding of photoinduced de-excitation dynamics in presence of defects in highly technologically relevant 2D MoS2 .