Radiation-induced optical change of ion-irradiated CdSeS/ZnS core-shell quantum dots embedded in polyvinyl alcohol

Semiconductor quantum dots (QDs) are receiving increasing interest for the production of scintillator detectors and dosimeters. For this reason, the investigation of the effects of ionizing radiation on the optical properties of QDs has become of great importance. In this paper, we present the optical characterization of colloidal CdSeS/ZnS core-shell quantum dots (QDs) embedded in a polyvinyl alcohol (PVA) matrix and irradiated with 2 MeV H+ and He+ ions at different fluences. With steady-state luminescence measurements, we investigate the ion irradiation effects on the luminescence spectrum of the irradiated samples. With time-resolved luminescence measurements, acquired with a Time Correlated Single Photon Counting (TCSPC) system, we evaluate the radiation-induced change in the QD charge carrier dynamics. Luminescence spectra show the appearance of new features related to damage of the PVA host. Time-resolved measurements highlight a shortening of the QD luminescence time constants as the ion fluence increases.