Blue-shift of UV emission in ZnO/graphene composites

► The ZnO and graphene composites were synthesized by a simple and nontoxic thermal evaporation process. ► In the PL spectra, when the mass ratio of graphene to ZnO increased, a regularly blue shift of the UV peak was found. ► The regularly blue shift of the UV peak might be attributed to the Burstein–Moss effect. ZnO and graphene composites (ZnO/GR) were prepared by a simple and repeatable thermal evaporation process, and both the reduction of graphene oxide and the loading of ZnO were achieved. The structural and optical properties were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM), atomic force microscope (AFM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and photoluminescence (PL) measurements. In the PL spectra, when the mass ratio of graphene to ZnO increased, a series of fluorescence quenching were found, and a regularly blue shift of the ultraviolet (UV) peak were also found, which might be attributed to the Burstein–Moss effect.