采用溶胶-凝胶法与静电纺丝技术相结合制备了PVA/[Gd(NO3)3+Yb(NO3)3+Er(NO3)3]复合纳米纤维, 将其进行热处理, 得到Gd2O3:Yb3+,Er3+上转换纳米纤维.采用XRD、SEM、TG-DTA、FTIR和荧光光谱对样品进行了表征.结果表明：复合纳米纤维为无定型, Gd2O3:Yb3+,Er3+上转换纳米纤维属于体心立方晶系, 空间群为Ia3.复合纳米纤维的平均直径约为140nm, 经过600℃焙烧后, 获得了直径约60nm的Gd2O3:Yb3+,Er3+上转换纳米纤维.当焙烧温度高于600℃时, 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81%.复合纳米纤维的红外光谱与纯PVA的红外光谱一致, 600℃以上时, 生成了Gd2O3:Yb3+,Er3+上转换纳米纤维.该纤维在980nm激光激发下发射出中心波长为522nm、560nm的绿色和659nm的红色上转换荧光, 对应于 Er3+离子的2H11/2/4S3/2→ 4Il5/2跃迁和 4F9/2→4Il5/2跃迁.在Gd2O3:Yb3+,Er3+上转换纳米纤维形成过程中, PVA分子起到了导向模板作用.PVA/[Gd(NO3)3+Yb(NO3)3+Er(NO3)3]复合纳米纤维在热处理过程中, PVA分解挥发, 稀土硝酸盐分解并氧化生成Gd2O3:Yb3+,Er3+纳米颗粒, 这些纳米颗粒相互联结起来形成了Gd2O3:Yb3+,Er3+上转换纳米纤维.

PVA/[Gd(NO3)3+Yb(NO3)3+Er(NO3)3] composite nanofibers were fabricated by the combination of sol-gel method and electrospinning. Gd2O3:Yb3+, Er3+ upconversion nanofibers were obtained by the calcination of relevant composite nanofibers. The samples were characterized by using XRD, SEM, TG-DTA, FTIR and fluorescence spectroscopy techniques. The results show that the composite nanofibers are amorphous in structure, and Gd2O3:Yb3+,Er3+ upconversion nanofibers are cubic in structure with space group Ia3. The mean diameter of the composite nanofibers is 140nm. The Gd2O3:Yb3+,Er3+ upconversion nanofibers of 60nm in average diameter were acquired at 600℃. The water, organic compounds, nitrates in the composite nanofibers are decomposed and volatilized totally, and the weight of the sample keeps constant when sintering temperature is above 600℃, and the total weight loss percentage is 81%. The FTIR spectrum of the composite nanofibers is basically the same as that of the pure PVA, and Gd2O3:Yb3+, Er3+ upconversion nanofibers are formed above 600℃. In the excitation of a 980 nm continuous wave diode laser, the Gd2O3:Yb3+, Er3+ nanofibers emitt strong green and red upconversion emissions centered at 522nm, 560nm and 659nm, respectively. The green emissions are attributed to the transitions of 2H11/2/4S3/2→4Il5/2 energy levels of Er3+ ions, and the red emission is assigned to the transition of 4F9/2→4Il5/2 energy levels of Er3+ ions. In the course of Gd2O3:Yb3+, Er3+ upconversion nanofibers formation, PVA acts as an oriented template. When the composite nanofibers are sintered, PVA is decomposed and evaporated, and rare earth nitrates are also decomposed and oxidized and then Gd2O3:Yb3+, Er3+ nanoparticles are formed. And these nanoparticles are mutually connected to form the Gd2O3:Yb3+, Er3+ upconversion nanofibers.