【摘要】 利用硝酸盐和尿素作为原料通过均相共沉淀法合成了分散性良好的Y₂O₃:Er³⁺和Y₂O₃:Er³⁺,Yb³⁺球形纳米粉体,粒径大小分别为100～115 nm和110～145nm.X-射线衍射结果显示,所制备的掺杂粉体仍然保持了立方Y₂O₃的物相结构.在980nm激光的激发下,Y₂O₃:Er³⁺样品的发光情况随着Er³⁺离子浓度的增加,上转换红光的发射强度都先增加后减小,而绿光的强度则逐渐减小.究其原因是交叉弛豫2H_11/2+⁴I_13/2→⁴I_9/2+⁴F_9/2,⁴F_7/2+⁴I_11/2→⁴F_9/2+⁴F_9/2,²H_11/2+⁴I_15/2→⁴I_9/2+⁴I_13/2和⁴I_13/2+⁴I_11/2→⁴F_9/2+⁴I_15/2的发生.Y₂O₃:Er³⁺,Yb³⁺则且随着Yb³⁺离子浓度的提高,上转换红、绿光的发射强度都增加,但上转换红光发射强度增加的幅度明显要大于上转换绿光发射强度增加的幅度.通过调整Yb"离子的掺杂浓度使其发光颜色在绿色、红色之间转变,其中单带红光上转换发光是由于在Yb³⁺离子掺杂浓度较高时,Er³⁺离子和Yb³⁺离子之间发生了能量反向传递.更多还原

【Abstract】 Spherical monodispersed Y₂O₃:Er³⁺ and Y₂O₃:Er³⁺,Yb³⁺ nanopowders were prepared via the homogeneous precipitation method using nitrate and urea as raw materials.The size of particles was 100-115 nm and 110-145 nm.The experimental results of phase evolution,which was studied by X-ray diffraction analysis,indicated that the Y₂O₃:Er³⁺ and Y₂O₃:Er³⁺,Yb³⁺ precursors completely transformed to Y₂O₃ phases.The cross relaxation processes of ²H_11/2+⁴H_13/2→⁴I_9/2+⁴F_9/2,⁴_7/2+⁴I_11/2→⁴F_9/2+⁴_F9/2,²H_11/2+⁴I_15/2→⁴I_9/2+⁴I_13/2 and ⁴I_13/2 +⁴I_11/2→⁴F_9/2+⁴I_15/2 are responsible for tuning from green to red upconversion（UC） emission in Y₂O₃:Er³⁺ nanopowders under 980 nm excitation.Single red UC emission obtained in Y₂O₃:Er³⁺,Yb³⁺ nanopowder is attributed to the energy back transfer(EBT:⁴S_13/2（Er）-PF_7/2（Yb） → ⁴I_13/2（Er）+²F_5/2（Yb）) process between Er³⁺ and Yb³⁺ ions at high concentration of Yb³⁺ ions at 980 nm excitation.更多还原