High quantum yield, photoluminescence tunability, and sensitivity to theenvironment are hallmarks that make carbon nanodots interesting for fundamental research andapplications. Yet, the underlying electronic transitions behind their bright photoluminescenceare strongly debated. Despite carbon-dot interactions with their environment should providevaluable insight into the emitting transitions, they have hardly been studied. Here, we investigatethese interactions in a wide range of solvents to elucidate the nature of the electronic transitions.We find remarkable and systematic dependence of the emission energy and kinetics on thecharacteristics of the solvent, with strong response of the photoexcited dots to hydrogenbonding. These findings suggest that the fluorescence originates from the radiativerecombination of a photoexcited electron migrated to surface groups with holes left in thevalence band of the crystalline core. Furthermore, the results demonstrate the fluorescencetunability to inherently derive from dot-to-dot polydispersity, independent of solventinteractions.
|Numero di pagine||5|
|Rivista||THE JOURNAL OF PHYSICAL CHEMISTRY LETTERS|
|Stato di pubblicazione||Published - 2016|
All Science Journal Classification (ASJC) codes
- Physical and Theoretical Chemistry