Coprecipitation synthesis and properties of color tunable and upconversion luminescence in Tb³⁺ and Yb³⁺ co-doped Y(PO₃)₃ materials

Abstract

Tb3+ and Yb3+ co-doped Y(PO3)3 upconversion luminescence phosphors were prepared by coprecipitation method. The structure and optical properties of the as-synthesized Y(PO3)3: Tb3+,Yb3+ samples were investigated by XRD, SEM, FI-IR and upconversion luminescence spectrophotometer (UPL), respectively. XRD results show that the as-synthesized samples are Tb3+ and Yb3+ co-doped Y(PO3)3 crystals with monoclinic structure (space group P21/c). UPL results display that the obtained Tb3+ and Yb3+ co-doped Y(PO3)3 samples emit the Tb3+ characteristic upconversion blue-green luminescence under 980 nm excitation. The doping content of Tb3+ ions affects the upconversion luminescence properties of the as-prepared Y(PO3)3: x Tb3+, 20%(mole fraction,the same below) Yb3+ samples. When the doping amount of Tb3+ is 2%-10%, the 5D4→7F6 emission peak of the Y(PO3)3: x Tb3+, 20% Yb3+ samples splits into two emission peaks centered at 481 nm and 491 nm. The dominant upconversion peak is located at 547 nm for the Y(PO3)3: x Tb3+, 20% Yb3+ samples when the Tb3+ doping content is 10%-20%. The concentration quenching can be observed when the doping amount of Tb3+ is over 20%. The doping ratio of Tb3+ to Yb3+ and the excitation power density also exhibit effect on the upconversion luminescence properties of the prepared samples. The upconversion blue-green emission color of the as prepared Tb3+ and Yb3+ co-doped Y(PO3)3 samples can be tuned by changing the doping amount ratio of Tb3+ to Yb3+.The upconversion luminescence mechanism of Y(PO3)3: Tb3+, Yb3+ samples was also discussed. The 5D3→7FJ (J=6,5,4) and 5D4→7FJ (J=6,5,4,3) upconversion luminescence are attributed to a three- and two-photon absorption mechanisms, respectively.

Keywords

• y(po₃)₃
• tb³⁺/yb³⁺ co-doped
• coprecipitation method
• color-tunable
• up-conversion luminescence property