Fluorescence Correlation Spectroscopy of Methane-Burn Carbon Nanodots

Abstract

Carbon nanodots, i.e. c-dots, have recently emerged as new class of fluorescent labels with tunable emission characteristics, high quantum yields and photostability, and with a low toxicity as compared to semiconductor quantum dots. In a previous report by Geddes and co-workers [1] it was demonstrated that the emission properties of c-dots can be further amplified by plasmon supporting materials, such as silver island films, however, it was reported that inhomogeneity due to the c-dot size distribution complicated the interpretation of the emission data. In the present report we apply the technique of fluorescence correlation spectroscopy, FCS, to characterize c-dots synthetically realized by the flame combustion of hydrocarbon/oxygen mixtures where particles are collected from the exhaust gases in liquid traps. We report a correlation between the c-dots particle size distribution with the stoichiometric composition of the flame and compare results with fluorescence anisotropy measurements.[1] Yongxia Zhang, Helena Goncalves, Joaquim C. G. Esteves da Silva and Chris D. Geddes, Metal-enhanced photoluminescence from carbon nanodots, Chem. Commun. , 2011, 47, 5313-5315.