Cao B S, Wu J L, Wang X H, Feng Z Q, Dong B
J Nanosci Nanotechnol. 2016 Apr;16(4):3690-4. doi: 10.1166/jnn.2016.11833.
Er3+ doped Yb2Ti207 nanophosphors by Gd3+ codoping with nominal composition of (Er0.05Yb0.95-xGd3+)2Ti2O7 (x = 0, 0.2, 0.4, 0.6, 0.8, and 0.95) have been prepared by sol-gel method. Er3+-Gd3+ codoped Yb2Ti2O7 was characteristic of a typical face-centered cubic crystal phase, and the unit cell parameter increased linearly with the increase of Gd3+ concentration. Under a 976 nm laser diode excitation, both green and red upconversion emissions were observed and the upconversion emissions were enhanced significantly by Gd3+ codoping, showing the strongest green and red emissions at 80 mol% Gd3+ codoping. The intensity ratio of green to red emissions (Igreen/Ired) increased monotonously with the increase of Gd3+ concentration. The energy transfer between Yb3+ and Er3+ and the variation of local crystal field symmetry of Er3+ by the substitution of Yb3+ by Gd3+ ions led to the improvement of upconversion properties of Er3+-Gd3+ codoped Yb2TiO7 nanophosphors.
采用溶胶 - 凝胶法制备了名义组成为(Er0.05Yb0.95 - xGd3+)2Ti2O7（x = 0、0.2、0.4、0.6、0.8和0.95）的Gd3+共掺杂Er3+的Yb2Ti2O7纳米磷光体。Er3+-Gd3+共掺杂的Yb2Ti2O7具有典型的面心立方晶体相特征，且晶胞参数随Gd3+浓度的增加呈线性增加。在976 nm激光二极管激发下，观察到了绿色和红色上转换发射，并且通过Gd3+共掺杂显著增强了上转换发射，在Gd3+共掺杂80 mol%时显示出最强的绿色和红色发射。绿色与红色发射的强度比（Igreen/Ired）随Gd3+浓度的增加单调增加。Yb3+与Er3+之间的能量转移以及Gd3+离子取代Yb3+导致Er3+局部晶体场对称性的变化，使得Er3+-Gd3+共掺杂Yb2TiO7纳米磷光体的上转换性能得到改善。
