Optical Degradation of CdSe/ZnS Quantum Dots upon Gamma-Ray Irradiation

Abstract

We report quantitative changes to the fluorescent characteristics of quantum dots (QDs) following gamma irradiation. One CdSe/ZnS QD ensemble synthesized via a wet-chemistry approach was dispersed in hexane. Six identical dispersions were prepared, three of which were unexposed controls, whereas the other three were irradiated by a Co-60 source, incrementally to doses of 0.1, 1.0, 10, and 100 Gy. Fluorescence spectra were immediately collected after each irradiation. Emission spectra were fit to a three-component mixed Gaussian model, which included CENTRE, SHOULDER, and BACKGROUND Gaussians. For all of the irradiated samples, the CENTRE and SHOULDER Gaussian amplitude decreased with increased irradiation dose. The BACKGROUND Gaussian exhibited increased amplitude, blue-shift, and widening. The three control samples exhibited consistent unchanged fluorescent spectra during our experimental time scale. The fluorescent response of QDs to radiation provides the proof of concept for use of quantum dots as nov...