GdAlO3:Eu3+:Bi3+ nanophosphor: Synthesis and enhancement of red emission for WLEDs.

GdAlO3, GdAlO3:Eu3+ and GdAlO3:Eu3+:Bi3+ nanophosphors were synthesised by solution combustion technique. Pure orthorhombic phase was obtained from powder X-ray diffraction (PXRD) studies. Scanning electron microscopy (SEM) micrographs showed the porous, agglomerated and irregular shaped particles. The particle size obtained by transmission electron microscopy (TEM) measurement was in good agreement with the values obtained by Debye Scherrer's and W-H plots. The selected area electron diffraction (SAED) pattern show single crystalline nature of the sample. Photoluminescence (PL) measurements were carried out for GdAlO3:Eu3+ and GdAlO3:Eu3+:Bi3+ phosphors excited at a wavelength of 274nm. The characteristic emission peaks of Eu3+ ions were recorded at 590, 614, 655 and 695nm corresponding to 5D0→7FJ (J=1, 2, 3, 4) transitions respectively. However, with addition of Bi3+ ions in GdAlO3:Eu3+, PL intensity drastically enhanced. Orange red color was tuned to deep red color with the addition of Bi3+ ions in GdAlO3:Eu3+ phosphor. Therefore, the phosphor was highly useful as red component in WLEDs. A single well resoled glow peak at 225°C was recorded in GdAlO3 and GdAlO3:Eu3+. Further, with addition of Bi3+ ions, an additional peak at 300°C was recorded. TL glow curves of different UV-exposed GdAlO3:Eu3+:Bi3+ show two TL peaks at 207 and 300°C respectively. The 207°C peak show simple glow peak structure and its intensity increases linearly up to 25min and after that it decrease. [ABSTRACT FROM AUTHOR]