Engineering of Ultra-Violet Reflectors by varying Alternate Layers of Titania/Silica for Harmful UV-Protection
The primary requisite of engineering optical/photonic devices is either for scaling or altering the properties. Here, we present the engineering of ultra-violet (UV) reflectors made up of alternate layers of titania (TiO2) and silica (SiO2) by using sol-gel spin coating method. The choice of these two materials is appropriate to realize the optical reflectors due to their large refractive index contrast. The formation of multilayer films of TiO2 and SiO2 are studied by field-emission scanning electron microscopy (FESEM), while UV-vis spectroscopy measurement is performed to study the reflectance. By varying the number of TiO2/SiO2 stacks, we have achieved the maximum reflectance within the UV region at center wavelengths 335 nm, 358 nm, and 367 nm corresponding to the 3, 6, and 9 stacks-based reflectors. Finally, we summarize that these reflectors prohibit the propagation of ultraviolet light, and therefore, they are promising as UV protection coating.