Synthesis, spectral characteristics and energy transfer of SrLa2Al2O7:Mn4+, Dy3+

Abstract

Researchers usually co-dope other ions in Mn4+ doped phosphors to improve and regulate their luminescence properties for the improvement of their practicality. Here, we synthesize SrLa2Al2O7:R (RDy3+, Mn4+, and Dy3+/Mn4+) samples by solid-state method in air. The crystal structure and phase purity are confirmed by XRD patterns of samples. We investigate the morphology, luminescence properties, optimal doping concentration of Dy3+ and Mn4+ ions, lifetimes as well as the energy transfer from Dy3+ to Mn4+ ions. We observe yellow emission of SrLa2Al2O7:Dy3+ under excitation 355 nm in the region from 450 nm to 650 nm with chromaticity coordinates (0.4684, 0.5035) due to the 4F9/2 → 6H15/2 and 6H13/2 transitions of Dy3+ ion. SrLa2Al2O7:Mn4+ under excitation 355 nm emits far-red light in the region from 650 nm to 810 nm with chromaticity coordinates (0.7141, 0.2858) due to the transition 2Eg → 4A2g of Mn4+ ion. SrLa2Al2O7:4mol%Dy3+, 0.5mol%Mn4+ under excitation 355 nm contains the emission of both Dy3+ and Mn4+, and shows red emission with chromaticity coordinates (0.5899, 0.4055). The energy transfer process from Dy3+ to Mn4+ ions in SrLa2Al2O7:Dy3+, Mn4+ is verified by the spectral characteristics. The luminous mechanisms of samples are analyzed by energy level diagrams of Dy3+ and Mn4+ ions.