Quantitative imaging of carbon dimer precursor for nanomaterial synthesis in the carbon arc

TL;DR

This study uses laser-induced fluorescence to measure carbon dimer (C₂) distributions in a carbon arc, linking these profiles to nanomaterial growth regions and validating a self-consistent arc model.

Contribution

It provides the first comprehensive spatial and temporal measurements of C₂ in a carbon arc and validates a model predicting their distribution during nanomaterial synthesis.

Findings

C₂ profiles match nanostructure growth regions

C₂ density varies with arc operation mode

Model accurately predicts C₂ spatial profiles

Abstract

Delineating the dominant processes responsible for nanomaterial synthesis in a plasma environment requires measurements of the precursor species contributing to the growth of nanostructures. We performed comprehensive measurements of spatial and temporal profiles of carbon dimers (C$_2$) in atmospheric-pressure carbon arc by laser-induced fluorescence. Measured spatial profiles of C$_2$ coincide with the growth region of carbon nanotubes and vary depending on the arc operation mode, which is determined by the discharge current and the ablation rate of the graphite anode. The C$_2$ density profile exhibits large spatial and time variations due to motion of the arc core. A comparison of the experimental data with the simulation results of self-consistent arc modeling shows a good agreement. The model predicts well the main processes determining spatial profiles of carbon dimers (C$_2$).