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Abstract
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Solvent medium effects on the optical spectra of a carbon nanodot (C-dots) as a solvato(fluor)chromic indicator have been investigated. The molar fluorescence transition energies of C-dots in different aqueous low molecular weight alcohols (C1-C3) were interpreted in terms of the Kamlet, Abboud and Taft equation. Emission results demonstrate that acidity is the most influential feature for the case of lighter methanol and ethanol, whereas the polarizability of the mixed solvent was the dominant factor for the propanol. The preferential solvation of the C-dots under consideration in the mixed water/alcohol solvents has been studied and were analyzed using two different models. In words, solvent exchange process and an excess function model were employed to evaluate the extent of preferential solvation. Correspondingly, both models exploited, confirmed the tendency of C-dots to be preferably solvated by alcohols rather than water. Interestingly, with an increase in the length of the alcohol carbon chain the extent of preferential solvation illustrated a decreasing trend
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