为了获得新形貌的上转换发光纳米纤维材料,采用静电纺丝技术制备了PVP/[Y(NO3)3+Al(NO3)3+Er(NO3)3+Yb(NO3)3]复合纳米纤维,将其进行热处理,获得了Er3+,Yb3+:Y3Al5O12(Er3+,Yb3+:YAG) 上转换发光纳米纤维。热分析(TG-DTA)表明,当焙烧温度高于550 ℃时,PVP/[Y(NO3)3+Al(NO3)3+Er(NO3)3+Yb(NO3)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90.2 %。X射线衍射(XRD)分析表明,PVP/[Y(NO3)3+Al(NO3)3+Er(NO3)3+Yb(NO3)3]复合纳米纤维为非晶态,经900 ℃焙烧10 h后,获得了单相石榴石型的Er3+,Yb3+:YAG发光纳米纤维。傅里叶变换红外光谱(FTIR)分析表明,当焙烧温度为900 ℃时,生成了Er3+,Yb3+:YAG纳米纤维。扫描电子显微镜(SEM)分析表明,Er3+,Yb3+:YAG纳米纤维的直径约75 nm,长度大于100 μm。上转换发射光谱分析表明,该纤维在980 nm激光激发下发射出中心波长为522 nm和554 nm的绿色和650 nm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。对Er3+,Yb3+:YAG纳米纤维的形成机理进行了讨论,该技术可以用来制备其他稀土石榴石型化合物纳米纤维。

In order to obtain upconversion nanofibers materials of a new morphology,PVP/[Y(NO3)3+Al(NO3)3+Er(NO3)3+Yb(NO3)3] composite fibers were prepared by electrospinning,and Er3+,Yb3+:Y3Al5O12(Er3+,Yb3+:YAG for short) upconversion nanofibers were fabricated by calcination of the as-prepared composite nanofibers. Thermogravimetry and differential thermal analysis (TG-DTA) revealed that the water,organic compounds and nitrate salts in the composite nanofibers were decomposed and volatilized totally,and the weight of the sample kept constant when temperature was above 550 ℃,and the total weight loss percentage was 90.2 %. X-ray diffraction (XRD) results showed that the composite nanofibers were amorphous in structure,and pure phase Er3+,Yb3+:YAG nanofibers were obtained by calcination of the relevant composite fibers at 900 ℃ for 10 h. Fourier transform infrared spectrometer (FTIR) analysis manifested that crystalline Er3+,Yb3+:YAG upconversion nanofibers was formed at 900 ℃. Scanning electron microscope (SEM) analysis indicated that the diameter of Er3+,Yb3+:YAG upconversion nanofibers was about 75 nm,and the length was greater than 100 μm. Upconversion emission spectra showed under the excitation of a 980 nm continuous-wave diode laser,Er3+,Yb3+:YAG nanofibres emitted green and red upconversion emissions centered at 522,554 and 650 nm,respectively. The green(522 nm and 554 nm) and red(650 nm) emissions were attributed to the transitions of 2H11/2/4S3/2→4Il5/2 and 4F9/2→4Il5/2 energy levels of Er3+ ions. The formation mechanism of the Er3+,Yb3+:YAG nanofibers were preliminarily discussed. This method could be applied to prepare the other rare earths garnet-typed compound nanofibers.