Ultrafast charge transfer dynamics pathways in two-dimensional MoS2-graphene heterostructures: a core-hole clock approach

Author(s):Show less -

Garcia-Basabe, Yunier ^[1] ; Rocha, Alexandre R. ^[2] ; Vicentin, Flavio C. ^[3] ; Villegas, Cesar E. P. ^[2] ; Nascimento, Regiane ^[4] ; Romani, Eric C. ^[5] ; de Oliveira, Emerson C. ^[6] ; Fechine, Guilhermino J. M. ^[6] ; Li, Shisheng ^[7] ; Eda, Goki ^{[7, 8, 9]} ; Larrude, Dunieskys G. ^[6]

Affiliation

^[1] Univ Fed Integracao Latinoamer, UNILA, BR-85867970 Foz Do Iguacu - Brazil

^[2] Univ Estadual Paulista UNESP, Inst Fis Teor, BR-01140070 Sao Paulo, SP - Brazil

^[3] Brazilian Ctr Res Energy & Mat CNPEM, Brazilian Synchrotron Light Lab LNLS, BR-13083970 Campinas, SP - Brazil

^[4] Univ Fed Ouro Preto, Dept Fis, Campus Morro Cruzeiro, BR-35400000 Ouro Preto, MG - Brazil

^[5] Pontificia Univ Catolica Rio de Janeiro, Dept Fis, BR-22430060 Rio De Janeiro - Brazil

^[6] Univ Prebiteriana Mackenzie, MackGraphe Graphene & Nanomat Res Ctr, BR-01302907 Sao Paulo - Brazil

^[7] Natl Univ Singapore, Ctr Adv Mat Mat 2D, 2 Sci Dr 3, Singapore 117542 - Singapore

^[8] Natl Univ Singapore, Dept Phys, 2 Sci Dr 3, Singapore 117551 - Singapore

^[9] Natl Univ Singapore, Dept Chem, 3 Sci Dr 3, Singapore 117543 - Singapore

• Document type: Journal article
• Source: Physical Chemistry Chemical Physics; v. 19, n. 44, p. 29954-29962, NOV 28 2017.
• Web of Science Citations: 6

Abstract

Two-dimensional van der Waals heterostructures are attractive candidates for optoelectronic nanodevice applications. The charge transport process in these systems has been extensively investigated, however the effect of coupling between specific electronic states on the charge transfer process is not completely established yet. Here, interfacial charge transfer (CT) in the MoS2/graphene/SiO2 heterostructure is investigated from static and dynamic points of view. Static CT in the MoS2-graphene interface was elucidated by an intensity quenching, broadening and a blueshift of the photoluminescence peaks. Atomic and electronic state-specific CT dynamics on a femtosecond timescale are characterized using a core-hole clock approach and using the S1s core-hole lifetime as an internal clock. We demonstrate that the femtosecond electron transfer pathway in the MoS2/SiO2 heterostructure is mainly due to the electronic coupling between S3p-Mo4d states forming the Mo-S covalent bond in the MoS2 layer. For the MoS2/graphene/SiO2 heterostructure, we identify, with the support of density functional calculations, new pathways that arise due to the high density of empty electronic states of the graphene conduction band. The latter makes the transfer process time in the MoS2/graphene/SiO2/Si twice as fast as in the MoS2/SiO2/Si sample. Our results show that ultrafast electron delocalization pathways in van der Waals heterostructures are dependent on the electronic properties of each involved 2D material, creating opportunities to modulate their transport properties. (AU)

• FAPESP's process: 12/24227-1 - Optical properties and charge-transfer process studies for efficient organic photovoltaic cells: ab-initio simulations
• Grantee: César Enrique Pérez Villegas
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 15/26862-4 - Simulating electronic transport using QM/MM and adaptive Monte Carlo methods: applications to DNA Chips
• Grantee: Alexandre Reily Rocha
• Support Opportunities: Scholarships abroad - Research
• FAPESP's process: 12/50259-8 - Graphene: photonics and opto-electronics: UPM-NUS collaboration
• Grantee: Antonio Helio de Castro Neto
• Support Opportunities: Research Projects - SPEC Program
• FAPESP's process: 11/11973-4 - ICTP South American Institute for Fundamental Research: a regional center for theoretical physics
• Grantee: Nathan Jacob Berkovits
• Support Opportunities: Research Projects - Thematic Grants