Size-dependent excited state properties of CdS nanocrystals

CdS nanocrystals of different particle sizes dispersed in ZrO₂ films were fabricated by sol-gel and dipping method. The size dependent excited state optical properties were systematically investigated by photoluminescence, time-resolved photoluminescence and Raman spectroscopy. The experimental results show that the relaxation of the excited state is composed of two processes. The fast component that arises from band edge emission shows a weak dependence on particle size, while the slow component, which is attributed to the shallow defect level emission, exhibits strong dependence on particle sizes.