Yanan Zhu

Preparation and luminescence properties of rare-earth doped fiber with spectral blue-shift: SrAl 2 O 4 :Eu 2+ ,Dy 3+ phosphors/triarylsulfonium hexafluoroantimonate based on polypropylene substrate

Abstract The rare-earth doped fiber with spectral blue-shift based on long afterglow luminescent materials SrAl 2 O 4 :Eu 2+ ,Dy 3+ phosphors and an organic cationic photoinitiators-triarylsulfonium hexafluoroantimonate (TSHF) in the presence of polypropylene substrate (PP) was prepared by melt-spinning process. Scanning electron microscopy (SEM), infrared spectroscopy (IR), afterglow properties and luminescence properties were tested. The results of SEM and FTIR spectra showed that the fiber consisted of irregular particles and had independent structural constitution of SrAl 2 O 4 :Eu 2+ ,Dy 3+ phosphors, TSHF and polypropylene. Furthermore, it was observed that there existed the highest afterglow initial intensity for the fiber with the TSHF concentration of 5 wt.%. More interestingly, the emission peak shifted to blue area gradually as the TSHF doping increased. The rare-earth doped fiber was distributed on blue light area in the CIE 1931 chromaticity diagram, which showed more obvious blue-shift phenomenon than the yellow-green light of SrAl 2 O 4 :Eu 2+ ,Dy 3+ phosphors.

Effect of red emitting fluorescent pigment on fluorescent color of SrAl2O4:Eu2+,Dy3+ phosphors

Green-blue fluorescence emitting SrAl2O4:Eu2+,Dy3+ phosphors (SAOED) were coated by SiO2 and a coumarin type red-emitting fluorescent pigment (FP). The effects of the FP on the morphology, crystal structure, photoluminescence properties and fluorescent color of the SAOED phosphors were systematically investigated by scanning electron microscopy (SEM), FT-IR, X-ray diffraction (XRD), photoluminescence spectra and CIE-1931 chromaticity coordinates characterization. Even though the surface of the SAOED phosphors became rough after being coated with SiO2 and FP, crystal lattice of SrAl2O4 did not have any obvious lattice distortions. The photoluminescence spectra indicated that the SAOED phosphors could be used as the excitation light source to excite the FP to emit red fluorescence. The emission spectrum of the FP-coated SAOED consisted of a broad band with two emission peaks at 520 and 610 nm, and its fluorescence emission color was a mixed color of the SAOED phosphors and FP. The fluorescence color of the SAOED/SiO2/FP composites tended to transfer to red area with the increase of the FP content varying from 0.1% to 0.9%.

Structural characterization and optical properties of long-lasting CaAl 2 O 4 :Eu 2+ ,Nd 3+ phosphors synthesized by microwave-assisted chemical co-precipitation

Abstract The present paper reported the structural and luminescent properties of Eu2+ and Nd3+ doped CaAl2O4 phosphor. The samples were prepared by microwave-assisted chemical co-precipitation (MA-CCP), a synthesis technique which is suitable for small and uniform particle that could be used directly without grinding. The effects of different microwave temperatures on structure and photoluminescence behavior were studied. Formation of a phosphor and phase purity were confirmed by X-ray diffraction technique (XRD) with variable microwave temperatures. XRD analysis showed that the phosphors prepared by MA-CCP method at the temperature of 750, 900 °C, respectively and solid-state reaction (SSR) method at 1300 °C consisted of impurities. Commission Internationale de L’Eclairage (CIE) color coordinates of CaAl2O4:Eu2+,Nd3+ were suitable as blue light emitting phosphor. Excitation and emission peaks of the samples prepared by different methods in this study were almost the same. The images of SEM showed that the size of the phosphors prepared by MA-CCP method reached a submicrometer.

Luminous properties of skin–core structure new luminous fiber: SrAl2O4:Eu2+,Dy3+-PET/light conversion agent-PET

SrAl2O4:Eu2+,Dy3+-polyethylene terephthalate (PET)/light conversion agent-PET, which is a new skin–core structure luminous fiber that can emit red light in the darkness, was fabricated by melt spinning with the combination of light conversion agent-PET and SrAl2O4:Eu2+,Dy3+-PET. An energy transfer occurred between SrAl2O4:Eu2+,Dy3+ and light conversion agent, and the light conversion agent emitted red light absorbed from SrAl2O4:Eu2+,Dy3+. To investigate the effect of light conversion agent on the luminous properties of SrAl2O4:Eu2+,Dy3+-PET-light conversion agent, several kinds of luminous fiber that contained different light conversion agents were artificially manufactured and their luminous properties were investigated. Results showed that under near-ultraviolet excitation, the fluorescent color of luminous fiber was primarily located in the orange-red area, with more intense red color than the others.