Graphene quantum dots (GQDs) are one kind of carbon-based nanomaterials which can be used for numerous applications, such as energy conservation, luminescent solar concentrators, bioimaging, and biosensing. It has low toxicity, high conductivity and it shows exceptional optical properties, including photoluminescence (PL) emission which could be adjusted from blue to red emission depending on the solvent. Another interesting properties found in GQDs is anti-Stokes photoluminescence (ASPL). However, the mechanism of ASPL in GQDs was still unclear. In this study, GQDs were prepared with 1,3,6-trinitropyrene as the precursor, then dissolved in toluene (GQDs@TL). The results show that GQDs@TL has PL emission peak at ~595 nm when excited at ~530 nm and ~700 nm. It showed that GQDs@TL has large energy gain (~310 meV). To further understand the mechanism of ASPL, additional temperature-dependent measurements were done. We found that the large energy gain could be gained owing to the contribution of phonon energy and hot-band absorption energy (EHBA) coming from molecular and lattice vibration. Therefore, this study will conclude the mechanism of ASPL.
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