Synthesis and Characterization of Zn(1−x)Ni(x=0.01–0.03)O Nanofilms Under Specific Conditions: Enhancement of Red Emission, and Photodegradation Retarding Behavior

In this work, undoped and Nickel (1, 2, and 3%) doped ZnO nanofilms were synthesized on glass substrates by ultrasonic spray method. The structure was studied by X-ray diffraction (XRD). Optical properties of samples were analyzed by photoluminescence (PL) spectroscopy. Subsequently, sprayed nanofilms were used as catalysts in an experiment for the degradation of methylene blue (MB) under UV irradiation. XRD spectra confirmed the hexagonal ‘wurtzite’ structure with polycrystalline nature of undoped and Ni doped nanofilms, and revealed that no compound containing Nickel appeared confirming the good quality of the structures. Photoluminescence spectra showed that all samples exhibited strong UV emission with blue emission. The absence of green emission in all the spectra is obvious and unexpected. A regular red emission is strangely observed in the spectra of doped nanofilms only, which can be exploited by the development of photo or electroluminescent devices based on Ni doped ZnO. Phtodegradation of undoped ZnO exhibited high degradation rate activity by 87.1% compared to 61.4%, 49.7%, 72.7% of Ni doped ZnO (1%, 2%, and 3%) respectively. Therefore, Ni doping lowered the photocatalytic efficiency of ZnO nanofilms.