Effects of Ho3+ and Yb3+ doping concentrations and Li+ co-doping on the luminescence of GdVO4 powders

• Published in: Optical materials Vol. 45; pp. 76 - 81
• Main Authors: Gavrilović, Tamara V., Jovanović, Dragana J., Trandafilović, Lidija V., Dramićanin, Miroslav D.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.07.2015
• Subjects: Green downconversion; Ho3+-doped orthovanadate; Li+ co-doping; Red upconversion; Red upconversion; Green downconversion; Li+ co-doping; Ho3+-doped orthovanadate
• ISSN: 0925-3467; 1873-1252
• DOI: 10.1016/j.optmat.2015.03.013

[Display omitted] •Li+ co-doped powders have larger crystallite size and smaller lattice parameters.•Ho3+/Yb3+-doped GdVO4 exhibits dominant green DC emission.•Ho3+/Yb3+-doped GdVO4 exhibits dominant red UC emission.•7.5mol% Li+ co-doping results in more than double DC emission intensity.•10mol% Li+ co-doped powder enhances UC emission intensity by 2.2times. We present the structural and luminescent properties of Ho3+/Yb3+-doped GdVO4 and Li+-co-doped GdVO4:Ho3+/Yb3+ powder phosphors. The materials were prepared by high-temperature solid state method with different concentrations (between 0.5 and 2mol%) of dopant Ho3+ emitting ions and different concentrations (between 5 and 20mol%) of sensitizer Yb3+ ions. The dopant ions provided the material with intense luminescence emission; green emissions (centered at 542nm from 5F4,5S2→5I8 electronic transition of Ho3+ ions) resulted upon ultraviolet excitation, and red (centered at 659nm from 5F5→5I8 electronic transition of Ho3+ ions) upon near-infrared excitation. The co-doped materials were obtained under identical experimental conditions by adding Li+ ions (5, 7.5, 10, and 15mol%). The powders co-doped with 7.5mol% Li+ ions showed a downconversion emission intensity more than twice as high as the samples without Li+ co-doping. In upconversion, an equal intensification of emission was achieved with co-doping with 10mol% Li+. The influences of Ho3+/Yb3+ concentration ratio and Li+ co-doping level on emission color and emission branching was investigated and analyzed for both downconversion and upconversion emission. Increasing Yb3+ concentration was found to increase the share of dominant emission (green) in downconversion, but decreased the share of dominant emission (red) in upconversion.