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Transparent colloidal ZnO quantum-dot (QD)/graphene nanocomposites were formed on poly(ethylene terephthalate) (PET) substrates. Ultraviolet (UV)–visible absorption spectra showed a shoulder peak around 350 nm corresponding to the absorption of ZnO QDs. Optical transmittance of the ZnO QD/graphene/PET multilayer was approximately 80%. High-resolution transmission electron microscopy images showed that the ZnO QDs were distributed along the circumferences of the surfaces on the graphene layers. Current–voltage and current–time measurements on the UV photodetector after bending at 300 K exhibited the ON/OFF switching states and stability resulting from the light-induced conductivity of the flexible graphene layer. [ABSTRACT FROM AUTHOR]

Abstract: Transmission electron microscopy images of ultraviolet (UV) photodetectors based on hybrid polymer-ZnO quantum dots (QDs) incorporating graphene showed that the ZnO QDs were distributed at the circumference of the surface of the poly-N-vinylcarbazole (PVK) layer and that the graphene layer were attached to the surface of the ZnO QDs and PVK layer. Current–voltage (I–V) measurements on the UV photodetectors showed that the ratio of the photocurrent to the dark current was approximately 108 and that the photocurrent was significantly enhanced by using the graphene layer. The carrier transport mechanisms of the UV photodetectors are described on the basis of the I–V results. [Copyright &y& Elsevier]