Photoluminescence dynamics and ligand exchange in PbS/CdS core/shell nanocrystal films

Photoluminescence studies in PbS/CdS core/shell nanocrystal thin films reveal that the length of organic ligands at the nanocrystal surface controls the photoluminescence rise time and the short-lived decay component. The long-lived photoluminescence does not depend on the ligand length but strongly depends on the detection wavelength and temperature. We conclude that the observed complex photoluminescence dynamics are governed by a combination of energy transfer and exciton recombination and propose a method to separate these processes.