Ultrafast Charge Transfer and Delayed Recombination in Graphitic-CN/WTe<sub>2</sub> van der Waals Heterostructure: A Time Domain Ab Initio Study
Atish Ghosh, Biswajit Ball, Sougata Pal, Pranab Sarkar
Abstract
In search of an efficient solar energy harvester, we herein performed a time domain density functional study coupled with nonadiabatic molecular dynamics (NAMD) simulation to gain atomistic insight into the charge carrier dynamics of a graphitic carbon nitride (g-CN)–tungsten telluride (WTe2) van der Waals heterostructure. Our NAMD study predicted ultrafast electron (589 fs) and hole-transfer (807 fs) dynamics in g-CN/WTe2 heterostructure and a delayed electron–hole recombination process (2.404 ns) as compared to that of the individual g-CN (3 ps) and WTe2 (0.55 ps) monolayer. The ultrafast charge transfer is due to strong electron–phonon coupling during the charge-transfer process while comparatively weak electron–phonon coupling, sufficient band gap, comparatively lower nonadiabatic coupling (NAC), and fast decoherence time slow down the electron–hole recombination process. The NAMD results of exciton relaxation dynamics are valuable for insightful understanding of charge carrier dynamics and in designing photovoltaic devices based on organic–inorganic 2D van der Waals heterostructures.