OPTICAL AND STRUCTURAL PROPERTIES OF GREEN SYNTHESIZED GRAPHENE QUANTUM DOTS

Abstract

Hydrothermal synthesis of Graphene quantum dots (GQDs) was done using corn powder as a carbon source and water as a solvent. A high-resolution transmission electron microscope shows uniform size distribution with an average diameter of 42 nm. Fourier transform infrared analysis of synthesized GQDs indicates the presence of C=C bond, O H groups, and aromatic rings. The absorption spectrum of GQDs shows a sharp band at around 227 nm, corresponding to the π-π* transition, and a shoulder peak at 283 nm assigned to the n-π* transition. The band gap of produced GQDs corresponding to 283 nm is 4.07 eV. When the GQDs are excited at 350 nm, the photoluminescence (PL) spectrum with a peak maximum of 450 nm was observed. The band maximum shifted blue of about 100 nm when excited with the band edge of absorption. Hence the PL is excitation dependent. The GQDs could be used as a potential candidate for hazardous metal ions detection in drinking water, and as a catalyst in degrading hazardous dye in wastewater treatment.