scholarly journals Deciphering asymmetric charge transfer at transition metal dichalcogenide–graphene interface by helicity-resolved ultrafast spectroscopy

2021 ◽  
Vol 7 (34) ◽  
pp. eabg2999
Author(s):  
Hongzhi Zhou ◽  
Yuzhong Chen ◽  
Haiming Zhu
Keyword(s):  
Charge Transfer ◽  
Transition Metal ◽  
Ultrafast Spectroscopy ◽  
Spin Dynamics ◽  
Hole Injection ◽  
Transition Metal Dichalcogenide ◽  
Transfer Processes ◽  
Spin Polarized ◽  
Graphene Interface ◽  
Interfacial Charge

Transition metal dichalcogenide (TMD)/graphene (Gr) heterostructures constitute a key component for two-dimensional devices. The operation of TMD/Gr devices relies on interfacial charge/energy transfer processes, which remains unclear and challenging to unravel. Fortunately, the coupled spin and valley index in TMDs adds a new degree of freedom to the charges and, thus, another dimension to spectroscopy. Here, by helicity-resolved ultrafast spectroscopy, we find that photoexcitation in TMDs transfers to graphene by asynchronous charge transfer, with one type of charge transferring in the order of femtoseconds and the other in picoseconds. The rate correlates well with energy offset between TMD and graphene, regardless of compositions and charge species. Spin-polarized hole injection or long-lived polarized hole can be achieved with deliberately designed heterostructures. This study shows helicity-resolved ultrafast spectroscopy as a powerful and facile approach to reveal the fundamental and complex charge/spin dynamics in TMD-based heterostructures, paving the way toward valleytronic and optoelectronic applications.

scholarly journals Microsecond charge separation at heterojunctions between transition metal dichalcogenide monolayers and single-walled carbon nanotubes

2019 ◽  
Vol 6 (10) ◽  
pp. 2103-2111 ◽  
Author(s):  
Dana B. Sulas-Kern ◽  
Hanyu Zhang ◽  
Zhaodong Li ◽  
Jeffrey L. Blackburn
Keyword(s):  
Carbon Nanotubes ◽  
Charge Transfer ◽  
Transition Metal ◽  
Charge Separation ◽  
Single Walled Carbon Nanotubes ◽  
Transition Metal Dichalcogenide ◽  
Single Walled Carbon ◽  
Photocurrent Generation ◽  
Walled Carbon Nanotubes ◽  
Interfacial Charge

Heterojunctions of transition metal dichalcogenide monolayers and single-walled carbon nanotubes are promising for photocatalysis and photocurrent generation, with microsecond timescale charge separation and sub-picosecond interfacial charge transfer.

Observation of quantum-confined exciton states in monolayer WS2 quantum dots by ultrafast spectroscopy

Nanoscale ◽  
2021 ◽  
Author(s):  
Shuwen Zheng ◽  
Lei Wang ◽  
Hai-yu Wang ◽  
chenyu Xu ◽  
Yang Luo ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Transition Metal ◽  
Edge Effect ◽  
Quantum Confinement ◽  
Ultrafast Spectroscopy ◽  
Photophysical Properties ◽  
Quantum Confinement Effect ◽  
Confinement Effect ◽  
Transition Metal Dichalcogenide ◽  
Fundamental Study

Monolayer transition metal dichalcogenide quantum dots (TMDC QDs) could exhibit unique photophysical properties, because of both lateral quantum confinement effect and edge effect. However, there is little fundamental study on...

Extracting molecular responses from ultrafast charge dynamics at material interfaces

2020 ◽  
Vol 8 (35) ◽  
pp. 12062-12067
Author(s):  
Chenglai Wang ◽  
Yingmin Li ◽  
Wei Xiong
Keyword(s):  
Molecular Dynamics ◽  
Charge Transfer ◽  
Material Interfaces ◽  
Interfacial Charge Transfer ◽  
Molecular Responses ◽  
Charge Dynamics ◽  
Transfer Processes ◽  
Interfacial Charge

A method is developed and applied to transient VSFG spectroscopy, to retrieve molecular dynamics in complex interfacial charge transfer processes.

Dynamics of charge-transfer excitons in a transition metal dichalcogenide heterostructure

Nanoscale ◽  
2020 ◽  
Vol 12 (15) ◽  
pp. 8485-8492
Author(s):  
Ang Bian ◽  
Dawei He ◽  
Shengcai Hao ◽  
Yang Fu ◽  
Lu Zhang ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Transition Metal ◽  
Transition Metal Dichalcogenide ◽  
Cooling Process ◽  
Charge Transfer Excitons

Hot charge-transfer excitons are formed in a transition metal dichalcogenide trilayer heterostructure and diffuse during their cooling process.

Photoinduced transformations in semiconductor­metal nanocomposite assemblies

2002 ◽  
Vol 74 (9) ◽  
pp. 1693-1706 ◽  
Author(s):  
Prashant V. Kamat
Keyword(s):  
Charge Transfer ◽  
Fermi Level ◽  
Morphological Changes ◽  
Metal Layer ◽  
Oxide Semiconductor ◽  
Semiconductor Surface ◽  
Interfacial Charge Transfer ◽  
Transfer Processes ◽  
Photocurrent Generation ◽  
Interfacial Charge

Semiconductor­metal nanocomposites provide a simple and convenient way to tailor the properties of photocatalysts. Modification of semiconductor surface improves charge separation and promotes interfacial charge-transfer processes in nanocomposite systems. Charge accumulation in the metal layer results in Fermi-level equilibration raising the quasi-Fermi level of the composite close to the conduction band level of the oxide semiconductor. Phototransformations of such compositesincluding morphological changes, interfacial charge-transfer processes and photocurrent generation of TiO2-capped gold colloidsare presented in this review article.

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