Striking Similarities in the Fluorescence Behavior between Carbon Dots and Ionic Liquids: Toward Understanding the Fluorescence Behavior of Carbon Dots

Abstract

Despite several studies, convincing explanation for the fluorescence of carbon dots (CDs) and its excitation wavelength dependence behavior has not yet emerged. It may be noted that direct structure–property correlation can be misleading based on solely transmission electron microscopy micrographs as it does not fully reveal the possibility of heterogeneous nature of the samples in a sense that it does not fully reveal the possibility of having both carbonaceous nanoparticles as well as small organic molecular-based systems. The present work is undertaken specifically to address this issue. A detailed spectroscopic investigation comprising steady-state absorption, emission, time-resolved fluorescence, and fluorescence correlation spectroscopy (FCS) studies has been carried out on CDs, synthesized from two different sources. Similar investigations have also been carried out on the systems such as aromatic and aliphatic ionic liquids (ILs), which are known to be fluorescent in their neat conditions. Interes...