Charge trapping in hybrid electroluminescence device containing CdSe/ZnS quantum dots embedded in a conducting poly(N-vinylcarbozole) layer

Abstract

Charge transport in a multilayer hybrid electroluminescence (EL) device containing CdSe/ZnS quantum dots (QDs) embedded in hole-transporting poly(N-vinylcarbozole) (PVK) layer was investigated. The current-voltage (I-V) curve exhibited resistive transition at low bias voltage and a negative differential resistance region with increase in bias voltage, which can be explained in terms of a two-step charge transport process, i.e., holes trapping and the following hole-electron recombination in CdSe/ZnS QDs embedded in PVK layer. EL spectra showed that the recombination center would be restricted to CdSe/ZnS QDs at high bias voltage, which is in well agreement with the I-V results.