Temporal response analysis of trap states of single CdSe/ZnS quantum dots on a thin metal substrate

To clarify the influence of trap states on the emission dynamics of CdSe/ZnS colloidal quantum dots on metal and glass substrates, we measured the trap state lifetimes of single QDs on different substrates using the photon inter-detection time analysis method. The results indicate that the trap state lifetimes as well as the emission counting rates changed depending on the substrate. Although the reduction in the counting rate can only be understood by the fast energy transfer to the metal substrate, the changes in the trap state lifetime suggest the influence of the substrate on the trap state. Thus, we concluded that the blinking suppression on metal substrate is caused not only by the fast energy transfer, but also by the shortening of recovering time from the trap state.

► We experimentally investigated the influence of trap states on the emission dynamics of single QDs on metal and glass substrates using a photon inter-detection time analysis method.
► We found that the changes in the trap state lifetime suggest the influence of the substrate on the trap state.
► The results indicate that the trap state lifetimes as well as the emission counting rates changed depending on the substrate.