Web Release Date: January 16,
Upconversion Properties of Ln3+ Doped NaYF4/Polymer Composite Fibers Prepared by Electrospinning
and
Key Laboratory of Excited State Physics Changchun Institute of Optics, Fine Mechanics and Physics Chinese Academy of Sciences, and Graduate School of Chinese Academy of Sciences, 16 Eastern South-Lake Road, Changchun 130033, P. R. China, and College of Electronic Science and Engineering, JiLin University, ChangChun 130012, P. R. China
Received: August 30, 2007
In Final Form: October 31, 2007
Abstract:
Ln3+ doped (Yb3+,Tm3+ codoped and Yb3+,Er3+,Tm3+ tridoped) NaYF4/poly(vinyl pyrrolidone)(PVP) (Mw
1 300 000) composite fibers with an average diameter of 300-800 nm were prepared by electrospinning
and characterized by X-ray diffraction, field emission scanning electron micrography, and Fourier transform
infrared spectra. Their upconversion (UC) luminescence properties were studied in contrast to the corresponding
Ln3+ doped NaYF4 nanoparticles (15-20 nm) under 980-nm excitation. The results demonstrate that in the
Yb3+,Tm3+ codoped composite fibers the blue emission of 1G4-3H6 is dominantly strong, while in the
nanoparticles the red emission of 3F2,3-3H6 contributes considerably to the increase of the excitation power.
This indicates that the color purity of blue is improved greatly by the modification of PVP. In the tridoped
Yb3+,Er3+,Tm3+ composite fibers, white light with more stable color balance (blue 1G4-3H6 of Tm3+, green
2H11/2/4S3/2-4I15/2, and red 4F9/2-4I15/2 of Er3+) was obtained. The improved UC properties in the composite
fibers are attributed to the suppressed local thermal effect. The energy transfer and UC populating processes
are discussed.
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