Phase transition and electronic structure investigation of MoS2-reduced graphene oxide nanocomposite decorated with Au nanoparticles

Author(s)

Garcia-Basabe, Yunier ^[1] ; Peixoto, Gabriela F. ^[2] ; Grasseschi, Daniel ^{[3, 2]} ; Romani, Eric C. ^[4] ; Vicentin, Flavio C. ^[5] ; Villegas, Cesar E. P. ^[6] ; Rocha, Alexandre R. ^[7] ; Larrude, Dunieskys G. ^[3]

Affiliation

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

^[2] Fed Univ Rio Janeiro UFRJ, Chem Inst, Inorgan Chem Dept, BR-21941909 Rio De Janeiro - Brazil

^[3] Univ Prebiteriana Mackenzie, MackGraphe Graphene & Nanomat Res Ctr, BR-01302907 Sao Paulo - Brazil

^[4] SENAI Innovat Inst Virtual Prod Syst, BR-20911210 Rio De Janeiro - Brazil

^[5] Brazilian Ctr Res Energy & Mat CNPEM, Brazilian Synchrotron Light Lab LNLS, BR-13083970 Campinas, SP - Brazil

^[6] Univ Privada Norte, Dept Ciencias, Av Andres Belaunde Cdra 10 S-N, Lima 15324 - Peru

^[7] State Univ Sao Paulo, Inst Fis Teor, UNESP, BR-01049010 Sao Paulo - Brazil

• Document type: Journal article
• Source: Nanotechnology; v. 30, n. 47 NOV 22 2019.
• Web of Science Citations: 0

Abstract

In this work a simple approach to transform MoS2 from its metallic (1T' to semiconductor 2H) character via gold nanoparticle surface decoration of a MoS2 reduced graphene oxide (rGO) nanocomposite is proposed. The possible mechanism to this phase transformation was investigated using different spectroscopy techniques, and supported by density functional theory theoretical calculations. A mixture of the 1T'- and 2H-MoS2 phases was observed from the Raman and Mo 3d high resolution x-ray photoelectron spectra analysis in the MoS2-rGO nanocomposite. After surface decoration with gold nanoparticles the concentration of the 1T' phase decreases making evident a phase transformation. According to Raman and valence band spectra analyzes, the Au nanoparticles (NPs) induce a p-type doping in MoS2-rGO nanocomposite. We proposed as a main mechanism to the MoS2 phase transformation the electron transfer from Mo 4d(xy,xz,yz) in 1T' phase to AuNPs conduction band. At the same time, the unoccupied electronic structure was investigated from S K-edge near edge x-ray absorption fine structure spectroscopy. Finally, the electronic coupling between unoccupied electronic states was investigated by the core hole clock approach using resonant Auger spectroscopy, showing that AuNPs affect mainly the MoS2 electronic states close to Fermi level. (AU)

• 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: 15/10405-3 - Synthesis, characterization, functionalization and ordering of metallic nanostructures
• Grantee: Daniel Grasseschi
• Support Opportunities: Scholarships in Brazil - Post-Doctoral