Analyses of Cu impurity effects on the USP grown MgO thin films: Structural, optical and photocatalytic assessments

Unspoiled and copper (Cu) doped magnesium oxide (MgO) thin films were successfully grown via ultrasonic spray pyrolysis method on soda lime glass substrates. Aftermath of the varied impurity presence in the host material were examined by conducting scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray Diffraction (XRD), photoluminescence (PL) spectroscopy, ultraviolet-visible (UV) spectroscopy, and photocatalytic measurements. The structural observations unveiled that the grown films showed (101) plane orientations with no secondary phases such as Cu or copper oxide present. Also, the XRD data discovered that the grain size of pure MgO sample decreased owing to the fact that Cu impurities introduced into the host material lattice system. In addition to that, the SEM images revealed that the impurity addition into the MgO nanocrystallites switched molecular shapes from regular to spherical structures. Besides, the aimed elemental compositions in the synthesized thin films were verified by the XPS. Furthermore, the photocatalytic measurements uncovered that the right amount of the magnesium content in the host material can enhance and tune the photocatalytic performance of the MgO films as desired. In the optical measurements, it was observed that optical absorbance values increased in the presence of varied percentages although these increments followed a random trend in respect to the doping levels (0.5%, 1%, 2%, 4% and 8 wt.%). The PL spectra revealed that the intensity of luminescent emissions gradually decreased which can be ascribed to the imperfections as a result of the introduced Cu into MgO.