Investigation of structural and luminescence properties of Ho3+ doped YAlO3 nanophosphors synthesized through solution combustion route

YAIO(3):Ho3+ (1-5 mol%) nanophosphors have been prepared by solution combustion route using oxalyl dihydrazide (ODH) as a fuel. The final product was well characterized by powder X-ray diffraction (PXRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), UV-Vis, etc. PXRD patterns confirm the formation of highly crystalline orthorhombic phase structure. SEM and TEM studies show the particles are dumbbell shape, highly agglomerated and nano-size (similar to 30 nm). The direct energy band gap (E-g) values estimated from Tauc's relation were found to be in the range 5.76-5.99 eV. Photoluminescence (PL) studies show green (540 and 548 nm) and red (645 and 742 nm) emissions upon excited at 452 nm wavelength. The emission peaks at similar to 742 and 645 nm was associated with the transitions of F-5(4) -> I-5(7) and F-5(5) -> I-5(8) respectively. The higher energy bands located at 540 and 548 nm were associated with F-5(4), S-5(2) -> I-5(8) transitions. Thermoluminescence (TL) studies of gamma-irradiated YAlO3:Ho3+ (1-5 mol%) show two glow peaks at 223 and 325 degrees C recorded at a heating rate of 2.5 degrees C s(-1). The 223 degrees C glow peak follow linear behavior up to 1 kGy and after that, it showed sub-linearity. Up to 1 kGy, the phosphor is quite useful in radiation dosimetry. The kinetic parameters (E, b and s) were estimated from glow peak shape method. The CIE coordinate values lies within the green region. Therefore, the present phosphors may have potential application in WLEDs as green phosphor. (C) 2013 Elsevier B.V. All rights reserved.