Velram Balaji Mohan; Manfred Stamm;Debes Bhattacharyya; Dongyan Liu; Krishnan Jayaraman
Abstract
This article focuses on the reduction of graphene oxides using different reductants and conditions systematically varying the chemical and physical structure, surface topography and chemistry and film thickness of reduced graphene oxide (rGO) films, with a focus on how these influence the property of ...
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This article focuses on the reduction of graphene oxides using different reductants and conditions systematically varying the chemical and physical structure, surface topography and chemistry and film thickness of reduced graphene oxide (rGO) films, with a focus on how these influence the property of most interest: electrical conductivity. The reduction process restores graphene oxide to a graphene-like structure, improving electrical conductivity while creating changes such as increased roughness, film thickness and new surface functionality. Films with smooth surfaces and minimal thicknesses have been shown to possess higher electrical conductivity. There have been minor changes in d-spacing and improvements in crystal perfection and orientation could be concluded from XRD patterns. Through XPS analysis, a significant decrease in the amount of oxygen functional groups at the surface has been noticed as the films get thinned.
Yamini Sharma; Seema Shukla; Shalini Dwivedi; Ramesh Sharma
Abstract
New material systems of intercalated compounds MTiS2 (M= Cr, Mn, Fe) have been systematically studied by ab-initio method. In order to investigate the effect of charge transfer from guest 3d transition metal atoms to host TiS2, the electronic and transport properties have been calculated using full potential ...
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New material systems of intercalated compounds MTiS2 (M= Cr, Mn, Fe) have been systematically studied by ab-initio method. In order to investigate the effect of charge transfer from guest 3d transition metal atoms to host TiS2, the electronic and transport properties have been calculated using full potential linearized augmented plane wave (LAPW) + local orbitals (lo) scheme, in the framework of density functional theory (DFT) with generalized gradient approximation (GGA) for the purpose of exchange correlation energy functional. From the energy bands and density of states it is observed that the 3d-states of M atoms contribute mainly to the conduction band, which results in increase in electrical and thermal conductivity of highly intercalated TiS2. The calculated electronic component γ which is derived from specific heats of intercalated TiS2 is quite high (2-50 mJ/mol K2) and increases substantially on intercalation. The 3d-states of transition metal M and Ti atoms which split due to the exchange interaction imparts magnetic properties to the MTiS2 systems. The calculated transport properties have been analysed on the basis of the density of states and correctly explain the origin of different magnetic ordered phases.
