TY - JOUR
T1 - Ultrafast Electronic Relaxation Dynamics of Atomically Thin MoS2 Is Accelerated by Wrinkling
AU - Xu, Ce
AU - Zhou, Guoqing
AU - Alexeev, Evgeny M.
AU - Cadore, Alisson R.
AU - Paradisanos, Ioannis
AU - Ott, Anna K.
AU - Soavi, Giancarlo
AU - Tongay, Sefaattin
AU - Cerullo, Giulio
AU - Ferrari, Andrea C.
AU - Prezhdo, Oleg V.
AU - Loh, Zhi Heng
N1 - Publisher Copyright:
© 2023 American Chemical Society.
PY - 2023/9/12
Y1 - 2023/9/12
N2 - Strain engineering is an attractive approach for tuning the local optoelectronic properties of transition metal dichalcogenides (TMDs). While strain has been shown to affect the nanosecond carrier recombination dynamics of TMDs, its influence on the sub-picosecond electronic relaxation dynamics is still unexplored. Here, we employ a combination of time-resolved photoemission electron microscopy (TR-PEEM) and nonadiabatic ab initio molecular dynamics (NAMD) to investigate the ultrafast dynamics of wrinkled multilayer (ML) MoS2 comprising 17 layers. Following 2.41 eV photoexcitation, electronic relaxation at the Γ valley occurs with a time constant of 97 ± 2 fs for wrinkled ML-MoS2 and 120 ± 2 fs for flat ML-MoS2. NAMD shows that wrinkling permits larger amplitude motions of MoS2 layers, relaxes electron-phonon coupling selection rules, perturbs chemical bonding, and increases the electronic density of states. As a result, the nonadiabatic coupling grows and electronic relaxation becomes faster compared to flat ML-MoS2. Our study suggests that the sub-picosecond electronic relaxation dynamics of TMDs is amenable to strain engineering and that applications which require long-lived hot carriers, such as hot-electron-driven light harvesting and photocatalysis, should employ wrinkle-free TMDs.
AB - Strain engineering is an attractive approach for tuning the local optoelectronic properties of transition metal dichalcogenides (TMDs). While strain has been shown to affect the nanosecond carrier recombination dynamics of TMDs, its influence on the sub-picosecond electronic relaxation dynamics is still unexplored. Here, we employ a combination of time-resolved photoemission electron microscopy (TR-PEEM) and nonadiabatic ab initio molecular dynamics (NAMD) to investigate the ultrafast dynamics of wrinkled multilayer (ML) MoS2 comprising 17 layers. Following 2.41 eV photoexcitation, electronic relaxation at the Γ valley occurs with a time constant of 97 ± 2 fs for wrinkled ML-MoS2 and 120 ± 2 fs for flat ML-MoS2. NAMD shows that wrinkling permits larger amplitude motions of MoS2 layers, relaxes electron-phonon coupling selection rules, perturbs chemical bonding, and increases the electronic density of states. As a result, the nonadiabatic coupling grows and electronic relaxation becomes faster compared to flat ML-MoS2. Our study suggests that the sub-picosecond electronic relaxation dynamics of TMDs is amenable to strain engineering and that applications which require long-lived hot carriers, such as hot-electron-driven light harvesting and photocatalysis, should employ wrinkle-free TMDs.
KW - electron−phonon scattering
KW - nonadiabatic ab initio molecular dynamics
KW - strain engineering
KW - time-resolved photoemission electron microscopy
KW - transition metal dichalcogenides
KW - ultrafast carrier dynamics
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U2 - 10.1021/acsnano.3c02917
DO - 10.1021/acsnano.3c02917
M3 - Article
C2 - 37581747
AN - SCOPUS:85169017158
SN - 1936-0851
VL - 17
SP - 16682
EP - 16694
JO - ACS nano
JF - ACS nano
IS - 17
ER -