Comparison of the effect of non-metal and rare-earth element doping on structural and optical properties of CuO/TiO2 one-dimensional photonic crystals

The photonic crystal materials are new generation advanced materials with various application areas. One-dimensional (1-D) photonic crystals are one kind of that can be produced easily. High quality structural colored surfaces could be obtained by high dielectric contrast between stocked layers such as CuO and TiO2. In this study, five-layered CuO/TiO2 multilayers prepared by the sol-gel method grown on borosilicate glass substrates by spin coating. Nitrogen and Cerium ions were doped into the TiO2 structure. X-Ray Diffractometer (XRD), X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscope (SEM), Photoluminescence Spectroscopy (PL), UV-Vis Spectrophotometer (UV-Vis) and Optic Microscope (OM) devices were used to characterize the effects of these non-metal and rare earth dopants on the phase, structural and optical properties of coatings. Violet, indigo, green, yellow and red structural colors were obtained from photonic crystal coatings consist of monoclinic tenorite and anatase layers. It was found that the size of the anatase crystal decreased with the doping of both N and Ce elements. Also, both dopants have positive effects on improving surface morphologies. The lower crystalline size, the better surface morphology, and the more vivid structural color properties were obtained by Ce doping while a higher degree of redshift obtained by the N doping. (C) 2019 Elsevier B.V. All rights reserved.