Phonon-induced nonadiabatic and adiabatic mechanisms synergistically driving ultrafast interlayer transfer of photogenerated charges in heterostructures of g-C₃N₄ with MoTe₂ and WTe₂

Phonon vibration excitation is an effective approach to enhance photoelectric conversion efficiency of g-C₃N₄- based heterostructures, yet the influencing mechanism on interlayer transfer of photogenerated charges remains unclear. Herein, we show first-principles evidence of using g-C₃N₄ / transition metal dichalcogenide (MoTe₂ and WTe₂) heterostructures to achieve ultrafast interlayer transfer of photogenerated electrons and holes at the timescales of 4 ps and 200 fs, respectively. Our findings reveal that the fast transfers of photogenerated electrons and holes are both promoted by a nonadiabatic (NA) mechanism, driven via the coupling of donor and acceptor electronic states with the same phonon state. Notably, this coupling in the valence bands is significantly stronger than that in the conduction bands, which enhances interface atom motion, reduces interface distance, and strengthens wave-function overlap of spatial localized electronic states, thereby synergistically producing much faster hole transfer. Moreover, the hole transfer is also enhanced by an adiabatic (AD) mechanism through phonon-induced crossing of valence bands. Our study identifies that the synergistic effects of phonon-induced NA and AD mechanisms play a key role in interlayer transfer of photogenerated charges within g-C₃N₄-based heterostructures.

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