Photoluminescence enhancement of organic dye by graphene quantum dots

Sagar, Vijay Kumar, Veluthandath, Aneesh Vincent and Bisht, Prem Ballabh (2020) Photoluminescence enhancement of organic dye by graphene quantum dots. Journal of Photochemistry and Photobiology A: Chemistry, 400, [112614]. (doi:10.1016/j.jphotochem.2020.112614).

Record type: Article

Abstract

The charge transfer (CT) interaction between the blue emitting graphene quantum dots (GQDs) and an organic dye (fluorescein 27, F27) has been first studied by steady-state and time-resolved spectroscopy as a function of the pH. F27 exists in the form of different inherent fluorescent species depending on the pH of the solvent. At pH 7, the CT interaction of GQDs with F27 results in a small red shift in the absorption and fluorescence spectra of the dye. The results indicate formation of a weak van der Waals (vdW) complex in the ground state. The photoluminescence decay rate of the GQDs is generally unaffected in the mixture indicating the absence of dynamic quenching. The fluorescence intensity of F27-GQD system shows a 3-fold increase. Numerical simulations reveal that apart from the CT interaction, hotspots in the nearfield of the GQDs contribute to the fluorescence enhancement.

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