Synthesis and photoluminescence behaviour of ultra-fine particles of Eu-doped zirconia nanopowders

Ultra-fine particles with disordered structure lower the site symmetry of Eu-ions and thus modify the emission spectrum. This may lead to induce different colour emission from Eu-doped zirconia. Based on this concept, the main objective of this research work is to develop ultra-fine particles of Eu-doped zirconia via precipitation route using sodium borohydride as a precipitating agent. Despite being used as a precipitant, sodium borohydride helps to form loose as-synthesized powders. These loose powders further supports for controlling the growth of the particles during calcination. In this work, X-ray diffraction confirmed the pure phase of tetragonal zirconia at both 600 degrees C and 800 degrees C. FESEM and TEM micrographs suggested that the particles were found to be less agglomerated, ultra-fine and spherical in nature. The emission spectrum revealed two prominent emission peaks at 604 nm (due to D-5(0)-> F-7(2) transition) and at 590 nm (due to D-5(0)-> F-7(1) transition) when the samples were excited at two different excitations such as 393 nm and 463 nm. Moreover, the emission behaviour, asymmetric ratio and CIE-coordinates suggested that violet-blue or blue-based excitation source can be used for the application of colour tuning, as it generates reddish-orange or nearly white emission from Eu-doped zirconia.