Morphologies and up-conversion luminescence of Gd4O3F6:RE3+ (RE=Yb, Er, Ho and Tm) phosphors by Hydrothermal Synthesis

To develop novel upconversion (UC) phosphors in this paper, the Gd4O3F6:Yb3+, Er3+, Ho3+, Tm3+ samples were prepared by a facile hydrothermal route, and their morphologies and luminescence properties were investigated. When the hydrothermal reaction conditions change, the final morphologies of the phosphors show some difference, but the relatively dispersed particles could be all obtained. Upon 980 nm excitation, the 10%Yb3+-1%Er3+ and 10%Yb3+-1%Ho3+ doped Gd4O3F6 samples exhibit red and green emissions with the chromaticity coordinates of (0.639, 0.358) and (0.308, 0.682), respectively; the 10%Yb3+-1%Tm3+ doped Gd4O3F6 sample mainly shows a very strong emission peak around 800 nm, which is beneficial to deeper tissue penetration and reduced autofluorescence in bio-imaging. The corresponding UC mechanisms were elucidated through the laser power dependence of the UC emissions. The above results reveal that multicolor lights as well as the NIR emission can be obtained by adjusting the rare earth dopants in the Gd4O3F6 host.