Upconversion Properties of Ln³⁺ Doped NaYF₄/Polymer Composite Fibers Prepared by Electrospinning

Abstract

Ln 3+ doped (Yb 3+ ,Tm 3+ codoped and Yb 3+ ,Er 3+ ,Tm 3+ tridoped) NaYF 4 /poly(vinyl pyrrolidone)(PVP) (M w ≈ 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 Ln 3+ doped NaYF 4 nanoparticles (15-20 nm) under 980-nm excitation. The results demonstrate that in the Yb 3+ ,Tm 3+ codoped composite fibers the blue emission of 1 G 4 -3 H 6 is dominantly strong, while in the nanoparticles the red emission of 3 F 2,3 -3 H 6 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 Yb 3+ ,Er 3+ ,Tm 3+ composite fibers, white light with more stable color balance (blue 1 G 4 -3 H 6 of Tm 3+ , green 2 H 11/2 / 4 S 3/2 -4 I 15/2 , and red 4 F 9/2 -4 I 15/2 of Er 3+ ) 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.

Controlled synthesis and luminescence properties from cubic to hexagonal NaYF4:Ln3+ (Ln=Eu and Yb/Tm) microcrystals

“…Among the fluorides reported, NaYF 4 , one of the most efficient DC and UC host lattices, has attracted increasing attention [6][7][8][9][10][11][12]. It is well known that NaYF 4 may be prepared in two polymorphic forms, namely, cubic and hexagonal phases [13,14].…”

Photoluminescence of Ag nanoparticle embedded Tb3+/Ce3+codoped NaYF4/PVP nanofibers prepared by electrospinning

“…Electrospinning, as one of the most convenient techniques for producing one-dimensional nanomaterials, has been attracting considerable attention recently [1][2][3][4][5][6][7][8][9][10][11][12][13]. Electrospun nanofibers with a variety of morphologies (solid, hollow, porous, etc) and materials (organic, inorganic, organic-inorganic composites, etc) have been prepared successfully.…”

“…Chuangchote et al have studied the photoluminescence of (MEH-PPV)/PVP ultrafine composite nanofibers [11]. Due to the maximum phonon energies of fluoride glasses and crystals being considerable lower than those of many other host materials, Dong et al used NaYF 4 :Ln nanoparticles as the luminescent activators and studied the upconversion luminescence properties of Ln 3+ doped NaYF 4 /polymer electrospun fibers; they found that the color purity of blue is improved greatly by the modification of PVP [12]. Yang et al have also studied the PL properties of carbon/CdS coaxial electrospun nanofibers [13].…”

Upconversion Nanoparticle-Based Nanocomposites

“…When inorganic rare earth luminescent nanoparticles are dispersed into polymer hybrid precursors, various 1D rare earth luminescent materials with multiform morphologies such as fiber, wire, belt, and tube can be achieved readily via the electrospinning route, which has potential applications in fluorescent lamps and color displays [71][72][73]. Lin's group has demonstrated that the electrospinning route is also an effective approach to prepare UCNP-mSiO 2 multi-functional materials, which can act as promising drug carriers for biomedical applications [74][75][76][77][78][79].…”