Synthesis and photoluminescence properties of novel yellow-emitting Ba2Gd5-xDyxB5O17 phosphors

Single phase yellow-emitting Dy3+ ions doped Ba2Gd5B5O17 phosphors were synthesized by solid-state reaction technique at high temperature. The phase identification and photoluminescence properties of as-prepared phosphors were characterized by X-ray diffraction patterns, excitation and emission spectra, decay curves and temperature-dependent luminescence spectral measurements. Under 276 and 354 nm near-UV excitations, the studied phosphors exhibited two intense emission bands in blue (486 nm) and yellow (575 nm) regions due to the magnetic dipole (F-4(9/2)-> H-6(15/2)) and electric dipole (F-4(9/2)-> H-6(13/2)) transitions, respectively. The optimal doping concentration of Dy3+ ions was found to be x = 0.07 for Ba2Gd5-xDyxB5O17 phosphors. Under 354 nm excitation, the color coordinates (x, y) of Ba2Gd4.93Dy0.07B5O17 phosphor were located in the yellow region of Commission International de I-Eclairage 1931 diagram and hence it can be used as a potential yellow component in the fabrication of white light-emitting diodes. Furthermore, the decay curves were fitted to double-exponential function to find the excited state lifetimes of Dy3+ ions. Besides, the temperature-dependent luminescence measurements were made to explore the thermal stability and activation energy of the concentration-optimized Ba2Gd4.93Dy0.07B5O17 phosphor. The results obtained from the present investigation were discussed in detail and compared with the similar reported literatures.