Temperature dependence of photoluminescence properties of water-soluble CdS quantum dots

Abstract

Abstract We investigated the size dependence of band-edge photoluminescence (PL) dynamics for CdS quantum dots (QDs). The temperature dependence of the PL-decay profiles of CdS QDs with an average diameter of 3.7–6.0 nm was measured. The PL-decay profiles became longer as the temperature increased. Further, it was found that the temperature dependence of the PL-decay profiles depends greatly on the QD size. These experimental results can be understood by considering that the magnitude of the splitting energy between the bright-and dark-exciton states depends on the QD size and becomes larger as the QD size becomes smaller.