Hydrothermal synthesis and white light emission of cubic ZrO2:Eu3+ nanocrystals

Production of white light has been a promising area of luminescence studies. In this work, white light emitting nanocrystals of cubic zirconia doped with Eu3+ are synthesized by hydrothermal technique. The dopant Eu3+ is used to stabilize crystalline phase to cubic and at the same time to get red counterpart of the white light. The synthesis procedure is simple and precursor required no further annealing for crystallization. X-ray diffraction patterns show the crystalline phase of ZrO2:Eu3+ to be cubic and it is confirmed by Fourier Transform Infrared spectroscopy. From transmission electron microscopy images, size of the crystals is found to be ∼5 nm. Photoluminescence emission spectrum of the sample, on monitoring excitation at O2−-Eu3+ charge transfer state shows broad peak due to O2− of the zirconia and that of Eu3+ emission. Commission Internationale de l'éclairage co-ordinate of this nanocrystal (0.32, 0.34) is closed to that of the ideal white light (0.33, 0.33). Correlated color temperature of the white light (5894 K) is within the range of vertical daylight. Lifetime (1.32 ms) corresponding to 5D0 energy level of the Eu3+ is found to be far longer than conventional red counterparts of white light emitters. It suggests that the ZrO2:Eu3+ nanocrystals synthesized by hydrothermal technique may find applications in simulating the vertical daylight of the Sun.