Y_2O_3:Er~(3+)上转换纳米纤维的制备与性质研究

采用静电纺丝技术制备了PVA/Y(NO_3)_3+Er(NO_3)_3]复合纳米纤维,将其在适当的温度下进行热处理,得到Y_2O_3∶Er~(3+)上转换纳米纤维.XRD分析表明,PVA/Y(NO_3)_3+Er(NO_3)_3]复合纳米纤维为无定型,Y_2O_3∶Er~(3+)上转换纳米纤维属于体心立方晶系,空间群为Ia3.SEM分析表明,PVA/Y(NO_3)_3+Er(NO_3)_3]复合纳米纤维的平均直径约为130 nm;经过600 ℃焙烧后,获得了直径约60 nm Y_2O_3∶Er~(3+)上转换纳米纤维.TG-DTA分析表明,当焙烧温度高于600 ℃时,PVA/Y(NO_3)_3+Er(NO_3)_3]复合纳米纤维中水分、有机物和硝酸盐分解挥发完毕,样品不再失重,总失重率为80;.FT-IR分析表明,PVA/Y(NO_3)_3+Er(NO_3)_3]复合纳米纤维的红外光谱与纯PVA的红外光谱基本一致,600 ℃时,生成了Y_2O_3∶Er~(3+)上转换纳米纤维.该纤维在980 nm激光激发下发射出中心波长为522 nm、561 nm的绿色和658 nm的红色上转换荧光,对应于 Er~(3+)的~2H_(11/2)/~4S_(3/2)→~4I_(l5/2)跃迁和~4F_(9/2)→~4I_(l5/2)跃迁.对Y_2O_3∶Er~(3+)上转换纳米纤维的形成机理进行了讨论,该技术可以推广用于制备其他稀土氧化物上转换纳米纤维.

Study on Fabrication and Properties of Y_2O_3:Er~(3+) Upconversion Nanofibers

PVA/Y(NO_3)_3+Er(NO_3)_3] composite nanofibers were fabricated by electrospinning.Y_2O_3∶Er~(3+) upconversion nanofibers were obtained by calcination of the relevant composite nanofibers. XRD analysis revealed that PVA/Y(NO_3)_3+Er(NO_3)_3] composite nanofibers were amorphous in structure, and Y_2O_3∶Er~(3+) upconversion nanofibers were cubic in structure with space group Ia3. SEM images indicated that the mean diameter of the composite nanofibers was 130 nm, and Y_2O_3∶Er~(3+) upconversion nanofibers of 60 nm in average diameter were acquired at 600 ℃. TG-DTA analysis revealed that the water,organic compounds, nitrates in the composite nanofibers were decomposed and volatilized totally, and the weight of the sample kept constant when sintering temperature was above 600 ℃, and the total weight loss percentage was 80%. FT-IR analysis manifested that the spectrum of the composite nanofibers was basically the same as that of the pure PVA, and Y_2O_3∶Er~(3+) upconversion nanofibers were formed at 600 ℃.The upconversion spectroscopic properties of the Y_2O_3∶Er~(3+) nanofibres were investigated under the excitation of a 980 nm continuous wave diode laser. The Y_2O_3∶Er~(3+) nanofibers emitted strong green and red upconversion emissions centering at 522 nm,561 nm and 658 nm, respectively. The green emissions were attributed to the transitions of ~2H_(11/2)/~4S_(3/2)→~4I_(l5/2) energy levels of Er~(3+) , and the red emission was assigned to the transition of ~4F_(9/2)→~4I_(l5/2) energy levels of Er~(3+) . The formation mechanism of Y_2O_3∶Er~(3+) upconversion nanofibers was advanced. The technique could be applied to fabrication of other rare earth composite oxides upconversion nanofibers.