Samsung Advanced Institute of Technology

Upon demonstrating self luminescing quantum dot based light emitting devices (QD-LEDs), rapid Auger recombination acts as one of the performance limiting factors. Here, we report the Auger processes of highly luminescent InP/ZnSe/ZnS QDs with different mid shell structures that affect the performances of QD-LEDs. Transient PL measurements reveal that exciton exciton binding energy is dependent on the mid shell thickness, which implies that the intercarrier Coulomb interaction caused by the introduction of excess charges may come under the influence of mid shell thickness, in contrast with the nearly stationary single exciton behavior. Photochemical electron doping and optical measurements of single QD show that negative trion Auger recombination exhibits strong correlation with mid shell thickness, which is supported by the dynamics of hot electron generated in the mid shell. These results highlight the role of excess electrons and the effects of engineered shell structures in InP/ZnSe/ZnS QDs, which eventually determine the Auger recombination and QD-LED performances.