Energy and charge transfer effects for hybrids of perovskite CsPbBr₃ quantum dots on organic semiconducting rubrene nanosheet

Functionalized perovskite CsPbBr₃ quantum dots (CsPbBr₃-QDs) were loaded on the surface of a p-type organic rubrene (5,6,11,12-tetraphenyltetracene) nanosheet (NS) for the fabrication of a new hybrid nano-system. Using a high–resolution laser confocal microscope, the nanoscale photoluminescence (PL) characteristics of the CsPbBr₃-QDs/rubrene-NS hybrids were investigated. We observed a significant enhancement of the PL intensity of the rubrene-NS after the hybridization with the CsPbBr₃-QDs, which originated from the fluorescence resonance energy transfer from the CsPbBr₃-QDs to the rubrene-NS. The PL enhancement ratio varied according to the density of the QDs on the NS. To investigate the hybridization effect with CsPbBr₃-QDs on the electrical characteristics of the rubrene-NS, we fabricated field-effect transistors (FETs) using the pristine and hybrid samples as an active layer. The currents of both FETs using the pristine rubrene-NS and hybrid QDs/rubrene-NS increased with light irradiation through the contribution of photo-excited charges. After the hybridization with the CsPbBr₃-QDs on the rubrene channel, both the electrical current and mobility decreased compared with the pristine rubrene-based FET. This can be explained by the relative decrease of hole concentration in the active channel region near dielectric layer through the interfacial charge transfer between the QDs and the NS, as well as the de-doping effect of the QDs on the rubrene-NS. Thus, we observed the energy and charge transfer effects for the CsPbBr₃-QDs/rubrene-NS hybrids, which can be applied to advanced nanoscale photonics and optoelectronics.