Optical Characterisation of the Graphene Quantum Dots (GQDs)

Sushanta Sapkota

doi:10.59973/emjsr.395

Authors

Sushanta Sapkota School of Mathematics and Physics, University of Portsmouth, PO1 3QL Portsmouth, UK

DOI:

https://doi.org/10.59973/emjsr.395

Keywords:

Graphene Quantum Dots, Optical properties, Emission spectra

Abstract

As an emerging material, graphene quantum dots (GQDs) have attracted significant research attention in recent years. Owing primarily to their stable photoluminescence and biocompatibility, GQDs exhibit excellent optical, electrical, and chemical properties. With the objective of performing optical characterization of GQD samples, this report introduces the fundamental theory of fluorescence and correlates it with the experimental findings. Fluorescence spectroscopy and UV-Vis Absorption spectrometer were employed to measure the fluorescence spectrum, lifetime decay and absorption spectra of multiple blue and green samples, including measurements at cryogenic temperatures. In addition, exponential functions fitted to the decay data were compared with the deconvoluted Gaussians from the emission spectra, corresponding to specific underlying electronic transitions. Although most peak wavelengths, fluorescence intensities and decay times were consistent with reported literature values, some unexpected deviations were observed. Nevertheless, the primary objective of acquiring the temperature-dependent intensity and fluorescence lifetime of the GQD samples were successfully achieved within the limited time and resources available for this project.

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