Upconversion emission properties and tunable morphologies of Y6WO12:Yb3+/Er3+ phosphor

Yb3+/Er3+ co-doped Y6WO12 phosphors are prepared by hydrothermal method and subsequently calcination. According to tuning the EDTA usage, the phosphors present four morphologies (cylinder, short-cylinder, flower-like and triangle shape). It is found that the usage of EDTA play crucial role in the formation of morphology. Based on the DSC-TG curves, the pure Y6WO12 are obtained by annealing the precursors at a wide range of temperatures. After annealing, strong red emissions and weak green emissions are observed under 980 nm excitation, which is different from the uncalcined products (green emissions are stronger than red emissions). Then we studied the changing tendency of the upconversion (UC) luminescence properties of the calcined and uncalcined products. At last, the pumping power on the UC luminescence properties and the level diagram mechanism of Y6WO12:Yb3+/Er3+ phosphor have also been discussed. We think this work may have the guiding function for obtaining different morphologies by adjusting EDTA and provide new channel of changing the green to red ratio in these kinds of host.