Structural and optical properties of zirconium oxide (ZrO2) nanoparticles: effect of calcination temperature

In this article, we report the structural and optical properties of zirconium oxide (ZrO2) nanoparticles synthesized via chemical co-precipitation method. The effect of calcination temperature on structural and optical properties of ZrO2 nanoparticles is investigated through XRD, FESEM, EDX, FTIR, UV-Vis absorption, fluorescence emission and life time measurements. XRD spectrum reveals the tetragonal phase at calcination temperature 600 degrees C and crystallinity of samples increases with calcination temperature. At 800 degrees C the phase transition from tetragonal to tetragonal-monoclinic mixed phase is noticed. The FESEM images show the particles are of irregular shape and highly agglomerated. FTIR spectra also confirm the formation of ZrO2 in crystalline phase. From UV-vis absorption spectra it is found a strong quantization and varying band gap with calcination temperature. The change in emission wavelength and intensity with phase change is observed form fluorescence emission spectra. At higher calcination temperature emission intensity is decreased which may be due to the phase change and the formation of surface defects. The life time measurements also reveal the different trap states and life time with calcination temperature.