Formation and optoelectronic properties of graphene sheets with CdSe/CdS/ZnS quantum dots monolayer formed by Langmuir-Schaefer hybrid method

The monolayer formations of graphene sheets and CdSe/CdS/ZnS quantum dots (QDs) are studied at air-water interface by Langmuir-Blodgett (LB) technique. The heterojunction structures of graphene sheets covered by QDs and placed between metal electrodes demonstrate excellent and high sensitive ultraviolet (UV) photoresponse to detection wavelength of 365 nm. Excitation of QDs located at the surface of a single graphene layer induces very efficient electron transfer from the QDs to graphene monolayer. The thin film of hybrid structure is deposited by Langmuir-Schaefer (LS) method. The photoresponse of hybrid structure is obtained by UV illumination as photoexcited electron-hole pairs can be separated at the interface between graphene monolayer and QDs. The charge mobility can be enhanced by reducing the rate of recombination by directly transferring photogenerated charge carriers from QDs to graphene sheets. Application of CdSe/CdS/ZnS QDs with graphene sheets will open unique opportunities for high performance UV photodetector. (C) 2017 Elsevier B.V. All rights reserved.