Enhanced photoresponsive mobility of rubrene nanosheet-based organic field effect transistors through hybridization with CdSe/ZnS quantum dots

Organic field effect transistors (OFETs) were fabricated using a p-type rubrene single nanosheet (NS) as an active layer hybridized with n-type CdSe/ZnS quantum dots (QDs). The dark and photoresponsive (λ_ex = 455 nm) electrical characteristics of the rubrene NS-based OFETs were investigated with and without the QDs. In dark conditions, the source-drain current (I _DS) of the OFETs increased and the threshold voltage was shifted to a positive direction after the partial attachment of the QDs to the surface of the NS. We also observed that the laser confocal microscope (LCM) PL intensity of the rubrene NS decreased through the attachment of the QDs, due to the charge transfer effect. With light irradiation, the photoresponsive I_DS and mobility of the OFETs were considerably enhanced by the hybridization with QDs. The results originated from both the ground charge transfer and exciton dissociation effects at the interface of p-type rubrene and n-type QDs heterojunctions.