Interfacial trap-induced confinement of mobile carriers during illumination at a pentacene/lead-sulfide functional interface

Interfacial electronic properties at the pentacene/lead sulfide (PbS) interface in the dark under illumination were studied. With a small size of PbS colloidal quantum dot (CQD) (2.7 nm), photoinduced charge transfer at the pentacene/PbS CQD interface leads to a large threshold voltage shift in a pentacene/PbS CQD field effect transistor (FET). Through estimation of interfacial trap density by sub-threshold slope measurements in an FET structure, the mechanism by which threshold voltage shift occurs is discussed.