Synthesis and Photoluminescence Properties of Eu Doped BaLuO Nanomaterials of High Colour Purity for LEDs Applications.

Eu-doped BaLuO (1-10 mol%) bright red emitters were efficiently produced through an economical solution combustion technique. Phase formation and structural analysis was executed using the obtained specific X-ray diffraction (XRD) patterns. The pure rhombohedral form of BaLuEuO sample with R3(146) space group was achieved by Rietveld refinement analysis. Field emission scanning electron microscope (FE-SEM) as well as transmission electron microscopy (TEM) provides clustered nature of particles in 60-70 nm range. The energy band-gap of host lattice (4.9 eV) and BaLuEuO composition (5.50 eV) lie within the semiconductor range enhancing the area of their application. The existence of Ba, Lu, Eu & O elements in optimum composition (5 mol%) was proved via Electron diffraction studies (EDS). Under 396 nm excitation, the dominant transition D → F at 621 nm is obtained which is responsible for red luminescence of Eu ions. The Judd-Ofelt intensity parameters (Ω and Ω) were determined based on the emission intensities corresponding to the D → F and D​ → F​ transitions of the europium (III) ion, respectively. Critical distance for energy transmission among nearby Eu ions was found to be 13.71 Å. However, the colorimetric values of 5-10 mol% samples are very near to red coordinates (0.6667, 0.3333) of standard NTSC color system, and the values of CCT measured by the emission profiles fall in range of 1918 to 2942 K implying the participation of Eu doped nanophosphor in designing warm WLEDs for indoor lighting applications.