Photoluminescence study on the carrier localization in colloidal cadmium chalcogenide hetero quantum dots

CdSe/CdS core–shell and gradient alloy CdSeS hetero quantum dots (HQDs) were synthesized using a wet chemical technique. Both HQDs have had their carrier localization-influencing recombination mechanism and energy band gap structure carefully examined, and it has been found that they are sensitive to changes in temperature and excitation power. The integrated emission intensity of the HQDs increased linearly with increasing power, with a slope of 1.62 for the CdSe/CdS and 0.94 for the CdSeS HQDs. Increasing the excitation power caused the emission peak energies to shift lower in energy due to the bandgap renormalization effect. In addition, the full-width half-maximum (FWHM), which is related to the electron–phonon interaction, broadens and the photoluminescence (PL) peaks weaken as the temperature range increases from 80 to 300 K. Their findings are contrasted with those from two HQD samples.