Photoluminescence quenching of CdSe core/shell quantum dots by hole transporting materials

Photoluminescence quenching of colloidal CdSe core/shell quantum dots (QDs) with CdS, ZnS and CdS/CdZnS/ZnS shells in the presence of hole-transporting materials (HTMs) is studied by means of steady-state and time-resolved photoluminescence spectroscopy. Static quenching is surprisingly found to play an even more important role in the PL quenching process than the dynamic one originating from a hole transfer from QDs to HTMs. The static quenching efficiency of the QDs with single CdS shells of 3 and 6 monolayers is much larger than that of the QDs with a multilayer CdS/CdZnS/ZnS shell. The experimental results are important for understanding the control of the static quenching pathways in QDs by using multishell structures.