Multicolor tunable luminescence in Dy3+/Eu3+ co-doped CaLaGaO4 phosphors for advanced lighting and display technologies

Abstract

Tunable multicolor luminescence Dy³⁺ and Eu³⁺ co-doped CaLaGaO₄ phosphors are synthesis by a high-temperature solid-state reaction technique. The X-ray diffraction (XRD) studies confirmed the single phase tetragonal crystal structure for all the prepared samples, elemental and oxidation states are revealed by X-ray photoelectron spectroscopy (XPS) studies, FTIR studies confirmed the metallic and oxygen bonds existence in all the samples. CaLaGaO₄: Dy³⁺ phosphor exhibits strong emission peaks at 484 nm (blue) and 576 nm (yellow) under excited at 388 nm, with 0.7% Dy³⁺ doping being the optimum concentration. In addition, the possibility of energy transfer is demonstrated by spectrum overlap analysis of Dy³⁺ and Eu³⁺ in CaLaGaO₄: 0.7% Dy³⁺, y% Eu³⁺ co-doped phosphor. CaLaGaO₄: Dy³⁺/Eu³⁺ co-doped phosphors are excited under 388 nm, the emission spectra is consist of emission peaks at 484 nm, 576 nm, 590 nm, 613 nm, 652 nm, and 701 nm, which are corresponding to Dy³⁺ and Eu³⁺ ions. Moreover, the emission spectral data and fluorescence decay lifetimes evinced the energy transfer in CaLaGaO₄:Dy³⁺/Eu³⁺ co-doped phosphors. At 0.5% Eu³⁺, the energy transfer efficiency can reach 78%, and the reason is disclosed through energy transfer mechanism. By adjusting the doping of Eu³⁺ ion concentration in CaLaGaO₄: 0.7% Dy³⁺, y% Eu³⁺, the CIE and associated color temperature can be adjusted for accomplishing tunable luminescence from cold yellowish white light to cold white and warm reddish-orange emitting light. In summary, outcomes demonstrated that the prepared CaLaGaO₄: Dy³⁺/Eu³⁺ phosphors are viable candidates for multicolor tunable phosphors, with potential candidates for white light-emitting diodes (WLEDs) and display technologies.