Effect of Surface Defects on Auger Recombination in Colloidal CdS Quantum Dots

The effect of surface states originating from surface defects and capping reagents on Auger recombination in CdS quantum dots (QDs) are investigated by femtosecond transient absorption spectroscopy. Because of the strong size-dependent nature of Auger recombination and surface defects, the size dependence of Auger recombination is also conducted to reveal the effect of surface states. The lifetime of Auger recombination is very similar irrespective of surface states in all size regions and was proportional to D-6 (D: QD diameter). This result clearly shows that Auger recombination in CdS QDs does not depend on interfacial electronic structures originating from the surface defects and capping reagents of one monolayer level.