Multiwavelength Raman spectroscopy analysis of a large sampling of disordered carbons extracted from the Tore Supra tokamak

TL;DR

This study employs multi-wavelength Raman microscopy to analyze a diverse collection of disordered carbons, revealing new insights into their spectral behavior and broadening mechanisms, extending understanding across amorphous and nano-crystalline forms.

Contribution

It introduces a comprehensive multi-wavelength Raman analysis of various disordered carbons, connecting spectral features across different structural types and identifying a new broadening source.

Findings

Extended Raman behavior understanding for amorphous and nano-crystalline carbons

Differentiation of cluster sizes using excitation wavelength dependence

Identification of a new broadening mechanism in Raman spectra

Abstract

Disordered carbon often exhibit a complex Raman spectrum, with four to six components. Here, a large variety of disordered carbons, forming a collection of samples with a great variety of structures, are analysed using multi-wavelength Raman microscopy (325.0, 514.5, 785.0 nm). They allow us to extend Raman behaviour known for nano-crystalline graphite to amorphous carbons, (dependence with the excitation wavelength) and other known for amorphous carbons to nano-crystalline graphite, (differentiation of the smallest cluster size probed using different excitation wavelengths). Experimental spectra were compared to simulated spectra, built using known laws, to evidence a new source of broadening.