The degradation mechanism of CdSe/ZnS quantum dots (QDs) light-emitting
diodes (LEDs) was investigated with steady-state and time-resolved
photoluminescence measurements. Our study reveals that the degradation is
associated with the decreasing quantum efficiency of the CdSe/ZnS QDs in the
devices. Two mechanisms that cause the efficiency reduction were verified in
the experiments: i.e., thermal instability and luminescence quenching.