Novel orange and reddish-orange color emitting BaGd2O4: Sm3+ nanophosphors by solvothermal reaction for LED and FED applications

BaGd2O4 (BG):Sm3+ nanophosphors were synthesized by a solvothermal reaction method. The powder X-ray diffraction pattern confirmed their orthorhombic structure, and the morphological studies were carried out by taking the scanning and transmission electron microscopy images. The photoluminescence (PL) emission and PL excitation (PLE) spectra were investigated as a function of Sm3+ ion concentration. The PLE spectra revealed both Gd3+ and Sm3+ excitation bands in the shorter and longer wavelength regions, indicating that the efficient energy transfer occurred from the Gd3+ to Sm3+ ions in the BG host lattice. The PL spectra exhibited an intense orange emission due to ((4)G(5/2) -> H-6(7/2)) transition along with two other moderate intense emission peaks due to the ((4)G(5/2) -> H-6(5/2)) and ((4)G(5/2) -> H-6(9/2)) transitions. Based on the emission performance related to ((4)G(5/2) -> H-6(7/2)) transition, the Sm3+ ion concentration was optimized to be at 1 mol%. The low-voltage cathodoluminescent (CL) measurements were also performed for BG:1 mol% Sm3+ nanophosphors as a function of accelerating voltage and filament current. From the CL spectra, the reddish-orange emission was observed. The Commission International De I-Eclairage chromaticity coordinates of BG:Sm3+ nanophosphors were found to be very close to the chromaticity coordinates of Nichia Corporation developed amber light-emitting diodes. (C) 2014 Elsevier B.V. All rights reserved.