Study of field driven electroluminescence in colloidal quantum dot solids

Abstract

Semiconductor nanocrystals, or quantum dots(QDs), promise to drive advances in electronic light generation. It was recently shown that long range transport of charge, which is typically required for electric excitation and which is inherently limited in nanosized materials, can be avoided by developing devices that operate through local, field-assisted generation of charge. We investigate such devices that consist of a thin film of CdSe/ZnS core-shell QD placed between two dielectric layers and that exhibit electroluminescence under pulsed, high field excitation. Using electrical and spectroscopic measurements, we are able to elucidate the dynamics of charge within the QD layer and determine that charge trapping and field-induced luminescence quenching are the main limitations of device performance.