Concentration dependence of luminescence properties of GdNbO4:Er3+/Yb3+ synthesized through hydrothermal route

• Published in: Journal of alloys and compounds 2017-06, Vol.709, p.64-71
• Main Authors: Hirano, Masanori, Ishikawa, Katsuya
• Format: Article
• Language: English
• Subjects: Erbium; Excitation spectra; Gadolinium niobate; GdNbO4; Hydrothermal synthesis; Luminescence; Nanocrystals; Optical properties; Phosphors; Phosphorus; Photoluminescence; Spectral emissivity; Studies; Up-converted luminescence; Upconversion; Ytterbium
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2017.03.127

To investigate the concentration dependence of the optical, up-conversion, and photoluminescence properties of phosphors based on GdNbO4 co-doped with Er3+ and Yb3+ an approach through hydrothermal synthesis route including subsequent heating in air was adopted. A single phase of monoclinic fergusonite-type Gd1.00-(x+y)ErxYbyNbO4 solid solution (x = 0–0.50, y = 0–0.30) was directly formed as nanocrystals by the substitutional incorporation of 0–50 mol% Er3+ and 0–30 mol% Yb3+ under hydrothermal condition at 240 °C for 5 h. The nanocrystalline GdNbO4:Er3+/Yb3+ whose crystallite sizes are around 18–38 nm showed the up-converted emission in the green spectral region, 515–565 nm under excitation at wavelengths of 980 nm in addition to the photoluminescence under excitation both at 259 nm and at 377 nm. At the concentration of 20 mol% Er3+ (x = 0.20), the up-converted emission intensity of the Gd1.00-(x+y)ErxYbyNbO4 solid solution became the highest by the incorporation of 20 mol% Yb3+ (y = 0.20). Although the emission intensity of samples changed depending on their concentrations, x and y, the nanocrystalline GdNbO4 co-doped with 5 mol% Er3+ and 20 mol% Yb3+ presented the strongest up-converted emission. [Display omitted] •Fergusonite-type GdNbO4:Er3+/Yb3+ was hydrothermally formed at 240 °C.•The concentration dependence of up-converting emission was investigated.•In 20 mol% Er3+, up-converted emission became the highest at 20 mol% Yb3+.•Gd0.75Er0.05Nb0.20O4 presented the strongest up-converted emission.