Investigation on Novel Photoactive Carbon Materials for Their Unique Properties Relevant to Energy Conversion Ya-Ping Sun, Department of Chemistry, Clemson University An interesting observation in the quenching of luminescence emissions of the aqueous suspended small carbon nanoparticles by aliphatic amines is the significant deviation from the classical Stern-Volmer behavior, with reversed quenching (increasing luminescence intensities) at very low quencher concentrations. The results have major implications to the mechanistic understanding of photoluminescence emissions in carbon dots. Stern–Volmer plots for the quenching of luminescence intensities (400 nm excitation) of the carbon nanoparticles by ethylamine (top) and PEG550N (bottom) in aqueous solution. Absorption and emission (400 nm excitation: —; 440 nm excitation: — —) spectra of the aqueous suspended carbon nanoparticles (a photo shown as inset). Stern–Volmer plots for the quenching of luminescence intensities (400 nm excitation: -o-; 440 nm excitation: --) of the carbon nanoparticles by diethylamine (DEA) in aqueous solution.