Formation and luminescence properties of GdTiNbO₆:Er³⁺/Yb³⁺ through the hydrothermal route

Abstract

Up-converting of GdTiNbO₆-based complex oxide co-doped with 5 mol % Er³⁺ and 10 mol % Yb³⁺ (GdTiNbO₆:Er³⁺/Yb³⁺) was conducted through a mild hydrothermal route. A single phase of aeschynite-type GdTiNbO₆:Er³⁺/Yb³⁺ was crystallized under weak basic hydrothermal conditions at 240°C for 5 h. The aeschynite-type structure was maintained after heating up to 1050°C for 1 h in air. A single phase of euxenite-type GdTiNbO₆:Er³⁺/Yb³⁺ was formed by heating at 1300°C for 1 h through phase transformation. The GdTiNbO₆:Er³⁺/Yb³⁺ emitted luminescence in the green spectral region from 515 to 560 nm (²H_11/2 and ⁴S_3/2 levels) under direct and indirect excitation of Er³⁺ at wavelengths of 377 and 277 nm, respectively, in addition to up-converted luminescence under excitation at 980 nm. The luminescence intensity was enhanced by high-temperature heating.