Charge Transfer in the MoS₂/Carbon Nanotube Composite

Abstract

Composite MoS2/carbon nanotube material has been produced by hydrothermal decomposition of a mixture of multiwall carbon nanotubes (CNTs) and a water solution of ammonium molybdate and thiourea. Transmission electron microscopy and Raman spectroscopy showed formation of MoS2 layers on the CNT surface and MoS2 flakes. X-ray photoelectron spectroscopy revealed a downshift of C 1s peak of the composite as compared to the pristine CNT sample that was related to charge transfer between the components. This fact was confirmed by near-edge X-ray absorption fine structure spectroscopy which detected a decrease of intensity of π* resonance in the C K-edge spectrum after the MoS2 deposition. Quantum-chemical calculations of a CNT@MoS2 model showed a positive charging of the CNT surface. Comparison of field emission characteristics of CNTs and the composite indicated lowering of the voltage threshold in the latter sample.