Vacancy-Regulated Charge Carrier Dynamics and Suppressed Nonradiative Recombination in Two-Dimensional ReX2 (X = S, Se)

• DOI: 10.1021/acs.jpclett.2c02796
• Publication Date: 2022-11-10T12:29:35Z
• Authors: Wenzhen Dou; Ling Zhang; Biyu Song; Chenqiang Hua; Meimei Wu; Tianchao Niu; Miao Zhou
• Keywords: Dynamics; Charge carrier

Point defects in semiconductors usually act as nonradiative charge carrier recombination centers, which severely limit the performance of optoelectronic devices. In this work, by combining time-domain density functional theory with nonadiabatic molecular dynamics simulations, we demonstrate suppressed and prolonged lifetime two-dimensional (2D) ReX2 (X = S, Se) S/Se vacancies. particular, a S vacancy introduces shallow hole trap state ReS2, while Se both electron states ReSe2. Photoexcited electrons holes can be rapidly captured these defect states, release process is slow, contributes to an elongated photocarrier lifetime. The lies vacancy-induced low-frequency phonon modes that weaken electron–phonon coupling, well reduced overlap between wave functions decreases coupling. This work provides physical insights into 2D ReX2, may stimulate considerable interest using engineering for future nanodevices.