ENHANCED ENERGY TRANSFER IN CARBON QUANTUM DOT SOLIDS

Abstract

Carbon quantum dots (CQDs) with noble properties such as low-cost, easy production in a large scale and non-toxicity have been widely investigated in the synthesis as well as bio-applications aspects. However, their potential application in important opto-electronic devices such as organic light emitting diodes (OLEDs), solar cells and light sensors has not been fully explored yet. In this report, we compared absorption and emission properties of CQDs that were prepared by pyrolysis of citric acid and ethylenediamine in solution and solid states. The absorption spectrum of CQD solid was red-shifted by about 0.15 eV while its emission spectrum was red-shifted by 0.4 eV as compared with those of solution CQDs. It has been demonstrated that π- π interactions increase the density of sate and reduce the interdistance among CQDs in solid state giving rise to enhancement in energy transfer efficiency. The results would pave a new path to the deployment of CQDs in optoelectronic devices where thin films of CQDs are essential.