Investigations on Diffuse Reflectance of Aluminium Doped Titania

Abstract

Uniform nanosized anatase and rutile phase titania nanoparticles doped with aluminium were synthesized by sol-gel technique using titania isopropoxide as a starting precursor. The influence of various sol-gel conditions and dopant concentrations on the formation, phase, morphology and diffuse reflectance of NPs have been investigated and tentatively discussed. XRD studies clearly showed the formation of anatase and rutile phase of titania and also confirms that Al is not incorporated into the lattice of titania as no impurity peak of Al was found. EDX results confirm the presence of Al on the surface of titania. TEM and SEM micrograph show the uniformity in shape and size of synthesized nanoparticles. From the absorption spectra the band gap of the NPs was calculated and found to be higher than that of the bulk counterpart. The luminescence property of the NPs was studied by the emission spectrum, which confirms the presence of defect levels caused by the oxygen vacancies. The reflectance spectra of doped NPs calcined at 5000C shows 97-99% reflectance as compared to uncalcined undoped NPs having 91-99% reflectance for the visible region.