Temperature-dependent photoluminescence properties of Mn:ZnCdS quantum dots

Abstract

The thermal stability of quantum dots (QDs) is considered as one of the key factors for their applications in various devices, due to the inevitable current induced Joule heat. In this work, we report the temperature-dependent photoluminescence (PL) of Mn:ZnCdS QDs, with a designed structure of MnS/ZnS/CdS, in the temperature range from 80 to 480 K. It is found that the highest PL quantum yield (QY) of the Mn:ZnCdS QDs can reach up to 65% even at the high temperature of 360 K. Moreover, the optical performance exhibits an excellent thermal stability, since the close-packed Mn:ZnCdS QDs and the QDs/organic blend films can maintain 90% of their initial intensity at 400 K for a long time. Furthermore, the thermal quenching mechanism of Mn²⁺ ion emission is proposed. The results of the present work suggest that QDs with high PL QYs and enhanced thermal stabilities could be realized by blocking the nonradiative recombination centers with thick CdS shells.