Enhanced Luminescence and Energy Transfer of Bi3+/Dy3+ Co-doped La2Zr2O7 Nanophosphors for pc-LED Applications

Lanthanum Zirconate (La2Zr2O7) doped with Bi3+ and co-doped with Dy3+ ions were synthesized by Polyol method and their luminescence properties are reported in this study. From XRD results, the pure cubic phase with the Fd3̅m space group (#227) was confirmed for the as-prepared samples. Absorption studies were performed, to know the absorption properties and estimated the optical energy band gap values of the as-prepared samples. The Morphological studies of the as-prepared samples exhibits irregular shaped agglomerates with particle size between 60 and 90 nm. PL emission spectra of Bi3+ doped La2Zr2O7 emits blue colour located at 460 nm (3P1→1S0 transition) when excited at 330 nm. The Bi3+ and Dy3+ co-doped sample exhibits PL emission peaks around 480 nm (4F9/2→6H15/2) and 575 nm (4F9/2→6H13/2) when excited at 307 nm. From PL studies the optimized composition is identified as La2Zr2O7: 0.5 at% Bi3+; 2 at% Dy3+ which emits strong tunable blue-yellow emissions. The co-doping of Dy3+ with Bi3+ in the host lattice enhances the emission intensities which makes this as a promising compound for pc-LED applications.