Enhanced photoluminescence in CaZr_0.9SmxDy_(0.1-x)O₃ perovskites by Mg²⁺ and Al³⁺ co-doping for WLED applications

Energy efficient white light emitting single phase materials are yielding a widespread interest in the research field. Improving their quality and efficiency had become the main motive. In this work CaZr 0.9 Sm x Dy (0.1-x) O 3 compound with x = 0.025, 0.05 and 0.075 codoped with 1% mol and 10% mol of Mg 2+ and Al 3+ ions were prepared by solid state route and corresponding changes in the luminescence properties were studied. Orthorhombic (Pnma) perovskitestructure of the samples was confirmed from the x-ray diffraction spectra. The band gap of the Mg 2+ and Al 3+ codoped samples shows a decrease from the corresponding CaZr 0.9 Sm x Dy (0.1-x) O 3 due to the additional energy levels created near valence and conduction bands in the parent samples. Photoluminescence studies of Mg 2+ and Al 3+ co doped samples show enhancement in the emission peaks corresponding to excitation at 354 nm. The peaks at 484 nm and 575 nm due to the transition between 4 F 9/2 - 6 H 15/2 and 4 F 9/2 - 6 H 13/2 levels of Dy 3+ ions observed in CaZr 0.9 Sm x Dy (0.1-x) O 3 compound had been increased considerably which was absent for the peaks corresponding to Sm 3+ ions indicates that the effective charge transfer due to aluminiumco doping and local distortion due to magnesium co doping was centred around Dy 3+ ions. The chromaticity diagrams of corresponding samples were also studied.