Solid-State Reaction Synthesis Of Beta-Naref4: Yb3+, Er3+ (Re = Y, Lu, La, Gd) Phosphors And The Upconversion Luminescence Property Under 1550 Nm Excitation

Well-crystallized NaREF4: Yb3+, Er3+ (RE = Y, Lu, La, Gd) phosphors were synthesized by a solid-state reaction method. X-ray diffraction characterization showed that the synthesized samples were all pure hexagonal phase after a calcination process on the as-prepared precursors at 550 A degrees C for 2 h by using Na2CO3 as a fluxing agent. Upconversion spectral analysis showed that under a 1550 nm laser diode excitation, the samples emitted dominant green emission centered at 540 nm and red emission centered at 654 nm, which corresponded to the H-2(11/2)/S-4(3/2)-> I-4(15/2) and F-4(9/2)-> I-4(15/2) transition of Er3+ ions, respectively. Color-tunable upconversion luminescence was realized by the variation of Yb3+/Er3+ doping concentration and the types of the host materials, indicating the synthesized hexagonal Yb3+ and Er3+ co-doped NaREF4 phosphors potential applications in many fields, especially in biological imaging and detection.