Tuning the stoichiometry of the pulsed laser deposited composite films

Abstract

Graphene-based composite thin films were deposited on glass substrates using a laser-based approach, anointed Pulsed Laser Deposition (PLD), at room temperature. To eliminate some technical fabricating hurdles, we studied the annealing temperature effects on the chemical properties of nanocomposite films and their photocatalytic activity. Results indicate that the stoichiometry of the composite films and their optical characteristics can be adjusted accurately through an optimized annealing temperature. We thoroughly investigated the characteristics of the layers using various analyses, x-ray diffraction analysis, scanning electron microscopy, energy dispersive x-ray spectroscopy, and optical spectroscopies. We analyzed the film's functional groups and their alterations under different annealing temperatures using confocal Raman spectroscopy. Raman's results affirm the formation of a composite film with combined features of both precursors (ZnO and GQDs) at 300°C. We recorded a high degradation percentage of 84% for the sample to show a high photocatalytic ability to degrade dyes for optimized nanocomposite film. Under visible light irradiation, all ZnO-GQDs composite thin films showed a higher photocatalytic degradation of Rhodamine 6 G than pristine ZnO. We found dye degradation to be of the first order, following the Langmuir-Hinshelwood mechanism.