Preparation and luminescence of Dy3+/Tm3+ co-doped Ca3NbGa3Si2O14 glass-ceramics for w-LED

Abstract

In this work, a series of Dy3+ and Dy3+/Tm3+ ion activated Ca3NbGa3Si2O14 glass-ceramics were prepared by traditional melt crystallization method, and report on the structural, optical, and energy transfer (ET)-based photoluminescence (PL) properties of glass-ceramics co-doped Dy3+/Tm3+. The preparation of glass-ceramics was studied by DTA, XRD, SEM, and UV–vis photometer technology, phase composition, transmittance, optimum heat treatment conditions, and luminescence properties. The best heat treatment procedure for obtaining transparent and well-formed glass-ceramics is crystallization at 820 °C for 5 h. The spectra excited by Tm3+ and Dy3+ have intersections at 352 nm and 365 nm, which means that CNGS: Dy3+/Tm3+ can be effectively excited by 352 nm and 365 nm ultraviolet light. Under the excitation of 352 nm ultraviolet light, four main emission peaks corresponding to 1D2 →3F4, 4F9/2 → 6H15/2, 4F9/2 → 6H13/2, 4F9/2 → 6H11/2 were found at 456 nm, 484 nm, 577 nm, and 663 nm, respectively. When the optimal concentration (4 at.%) of Dy3+ is Co-doped with a different amount of Tm3+, the luminous color can be adjusted by adjusting the doping amount of Tm3+ and changing the excitation wavelength. There is an overlapping region between the emission spectrum of Tm3+ doped glass and the excitation spectrum of Dy3+ doped glass, which indicates that there is energy transfer between Tm3+ and Dy3+. In addition, CNGS: Dy3+/Tm3+ CIE coordinates show that the color coordinates (0.3324, 0.3352) when y = 0.02 under 365 nm excitation are closest to the standard white light (0.333, 0.333), indicating that this glass has potential applications in WLED devices.