Femtosecond photoluminescence up-conversion spectroscopy in Cu doped CdS quantum dots

Abstract Herein, femtosecond photoluminescence up-conversion (u-PL) spectroscopy has been carried out to elucidate charge carrier relaxation dynamics of the hole in 2 nm copper doped CdS (Cu: CdS) QDs. The hole capturing time at the Cu defect state from the valance band edge of the CdS host appeared significantly faster (437 fs) compared to pure CdS QDs (670 fs). This faster hole capturing in Cu: CdS QDs can compete with Auger-type cooling, and consequently, we can expect slower electron cooling in this system.