Preparation and Luminescent Properties of Polymer Fibers Containing Y2O3:Eu Nanoparticles by Electrospinning

2008 ◽  
Vol 8 (11) ◽  
pp. 6017-6022 ◽  
Author(s):  
Hongquan Yu ◽  
Hongwei Song ◽  
Guohui Pan ◽  
Libo Fan ◽  
Suwen Li ◽  
...  
Keyword(s):  
Weak Interactions ◽  
Charge Transfer Band ◽  
Emission Spectra ◽  
Luminescent Properties ◽  
Average Diameter ◽  
Radiative Transition ◽  
Polymer Fibers ◽  
Composite Fibers ◽  
Defect States ◽  
Excitation Spectra

In this paper, composite fibers of polyvinylpyrrolidone (PVP) and Y2O3:Eu3+ nanocrytals were prepared by electrospinning and characterized by electron microscope, Fourier transform infrared spectra (FT-IR) and X-ray diffraction (XRD). The composite fibers are in random orientation and with average diameter of ∼300 nm and length up to several ten micrometers. The luminescent properties were investigated and compared with the pure Y2O3:Eu3+ nanocrystals. Due to certain weak interactions between nanocrystals and PVP matrix, charge transfer band in the excitation spectra show slightly red shift for the fibers relative to in the case of pure Y2O3:Eu3+ nanocrystals. The PVP polymer may modified the surface defect states of nanocrystals, yielding decreased intensity ratio of 5D0–7F2 to 5D0–7F1 transition in the emission spectra. The fluorescence lifetimes of 5D0 level for Eu3+ in the composite fibers and Y2O3:Eu3+ nanocrystals were respectively determined to be 1.40 and 1.74 ms. The decreased fluorescence lifetime in the composite fibers was attributed to increased radiative transition rate, as result of the influence of refractive index of the surrounding PVP media instead of air.

scholarly journals Synthesis and Luminescent Properties of Eu3+/Tb3+ Rare Earth Ions Doped Li2SrSiO4 Phosphors

2018 ◽  
Vol 1 (1) ◽  
Author(s):  
Kaitao Yu ◽  
Lifang Wei ◽  
Jiaqi Shen
Keyword(s):  
Charge Transfer ◽  
Charge Transfer Band ◽  
Emission Spectra ◽  
Luminescent Properties ◽  
Rare Earth Ions ◽  
Luminescent Materials ◽  
Excitation Spectra ◽  
Solid State Method ◽  
X Ray ◽  
Uv Visible

The series of luminescent materials of Eu3 +, Tb3 + doped Li2SrSiO4 were synthesized by a high-temperature solid-state method. The phase purity of the samples was measured by X-ray powder diffraction (XRD). The luminescent properties of the samples were studied by UV-visible excitation spectra and emission spectra The It is found that the strong absorption of Eu3 + doped Li2-xSr1-xEuxSiO4 is from the 250 ~ 290 nm charge transfer band of Eu3 + and the 7F0 → 5L6 absorption transition of 393 nm. The strongest emission of the emission spectra at 393 nm is 614 nm and 701 nm, respectively, from the 5D0 → 7F2 and 5D0 → 7F4 transitions of Eu3 +. Tb3 + doped sample Li2-xSr1-xTb xSiO4 excitation spectrum is mainly composed of Tb3 + ion fd transition and charge transfer band composed of broadband, the strongest absorption at 269 nm, the emission of the main emission of 5D4 → 7F5 transition (542 nm).

Hydrothermal Synthesis and Size-Enhanced Chromaticity of Sr2ZnSi2O7:Eu3+ Nanoparticles

2008 ◽  
Vol 8 (3) ◽  
pp. 1449-1453 ◽  
Author(s):  
Junxi Wan ◽  
Youwei Yao ◽  
Guoyi Tang ◽  
Yitai Qian
Keyword(s):  
Bulk Material ◽  
Emission Spectra ◽  
Luminescent Properties ◽  
Blue Shift ◽  
Average Diameter ◽  
Hydrothermal Route ◽  
Excitation Spectra ◽  
Red Phosphor ◽  
Red Phosphors ◽  
20 Nm

Red phosphor Sr2ZnSi2O7:Eu3+ nanoparticles with an average diameter of 20 nm were successfully synthesized via a low-temperature hydrothermal route in order to understand the underlying relationship between size and luminescent properties. The nanometer-sized particles result in a distinct improvement in chromaticity and a high quenching concentration. According to emission spectra, the relative intensity of the 5D0 → 7F2 to 5D0 → 7F1 transitions in nanometer-sized phosphors is higher than that of the corresponding bulk material. The better chromaticity results from the more distorted lattices and relatively lower crystal symmetry around the Eu3+ ions, which is ascribed to the large surface area due to the nanometer size of the phosphor. Moreover, the nanometer-sized Sr2ZnSi2O7:Eu3+ red phosphor exhibits a shorter fluorescent lifetime and a blue-shift in excitation spectra compared to that of its bulk counterpart. These results indicate that size-induced enhancement of luminescent properties is an efficient way to obtain red phosphors with better chromaticity.

Luminescent Properties of La3PO7:Eu3+ Nanoparticles

2008 ◽  
Vol 8 (3) ◽  
pp. 1410-1413 ◽  
Author(s):  
Shaozhe Lü ◽  
Jishen Zhang
Keyword(s):  
Charge Transfer Band ◽  
Emission Spectra ◽  
Local Environment ◽  
Luminescent Properties ◽  
X Ray Diffraction ◽  
Excitation Spectra ◽  
Time Resolved ◽  
Transmission Electron ◽  
Light Excitation ◽  
Average Size

La3PO7:Eu3+ samples were prepared by combustion and annealing and characterized by X-ray diffraction and transmission electron microscopy. It was found that the average size of the particles is about 80 nm. The red emission from the 5D0 → 7F2 transition of the Eu3+ ions under ultraviolet light excitation is much stronger than the orange emission from the 5D0 → 7F1 transition. The emission spectra, charge transfer band, laser selective excitation spectra, and time-resolved spectra indicate that symmetry of the local environment of Eu3+ lacks an inversion center and Eu3+ ions occupy at least two types of sites in the La3PO7 crystal. The superior color chromaticity compared to other phosphates and borates doped with Eu3+ means La3PO7:Eu3+ may have potential as a luminescent material.

Synthesis and Luminescent Properties of Gd2MoO6:Eu3+

2015 ◽  
Vol 15 (10) ◽  
pp. 7765-7769 ◽  
Author(s):  
Sook Hyun Kwon ◽  
Byung Kee Moon ◽  
Jung Hyun Jeong ◽  
Hyun Kyoung Yang ◽  
Jung Hwan Kim
Keyword(s):  
Charge Transfer Band ◽  
Sol Gel ◽  
Emission Spectra ◽  
Luminescent Properties ◽  
X Ray Diffraction ◽  
Excitation Spectra ◽  
Light Emitting ◽  
Diffraction Patterns ◽  
White Light Emitting Diodes ◽  
Electron Microscope Image

A series of 6 mol% Eu3+ doped Gd2MoO6 samples were prepared by using the sol–gel method. The X-ray diffraction patterns of the samples confirmed their monoclinic structure after they were annealed at 1300 °C, and a scanning electron microscope image revealed closely packed particles. The excitation spectra showed that the intensity of the excitation band decreased and the charge transfer band shifted from 370 to 350 nm with decreasing sintering temperature. The emission spectra are dominated by the hypersensitive forced electron dipolar transition 5D0 → 7F2 at 612 nm. The as synthesized phosphor can be used as a red phosphor in white light emitting diodes.

Synthesis and Characterization of Y2O3:Eu3+ Film Derived by Sol-Gel Processing

2007 ◽  
Vol 336-338 ◽  
pp. 593-596
Author(s):  
Chun Yang ◽  
Jun Ying Zhang ◽  
Hai Bing Feng ◽  
Wei Chang Hao ◽  
Tian Min Wang
Keyword(s):  
Raw Materials ◽  
Sol Gel ◽  
Emission Spectra ◽  
Luminescent Properties ◽  
Dip Coating ◽  
Organic Additive ◽  
Excitation Spectra ◽  
Excitation Peak ◽  
Close Relationship ◽  
Dip Coating Technique

Y2O3:Eu3+ thin film was synthesized by sol-gel method with inorganic salt raw materials, and the crystal structure and luminescent properties were investigated. By adding organic additive to the sol, a homogeneous film with high luminescent intensity could be obtained by dip-coating technique on the surface of alumina sheet and quartz glass. Structures of the films were studied by XRD and SEM. The excitation spectra of the films showed a wide excitation peak from 200nm to 260nm, and the emission spectra had a strongest emission peak at 611nm which revealed a close relationship with the calcining temperature.

Luminescent Properties and Thermometry of CaWO4:Nd3+ in Near Infrared Region

2017 ◽  
Vol 893 ◽  
pp. 156-160
Author(s):  
Rong Xue Wang ◽  
Xiao Bing Luo
Keyword(s):  
Near Infrared ◽  
Emission Spectra ◽  
Luminescent Properties ◽  
Infrared Region ◽  
Excitation Spectra ◽  
Efficient Energy Transfer ◽  
Fluorescent Intensity ◽  
Sensor Device ◽  
The Matrix ◽  
Increasing Temperature

CaWO4: xNd3+ (x = 0.005, 0.008, 0.01, 0.015, 0.02, 0.025 0.03) powders have been synthesized by high-temperature solid state reaction. The results of the XRD indicate that Nd3+ ions have entered into the crystal lattice in all compounds successfully. The reflectance spectra show that the matrix has strong absorption. The emission spectra, excitation spectra and different lifetimes between CaWO4 and CaWO4: 0.5% Nd3+ indicate that efficient energy transfer occurs from WO42- cluster to Nd3+ ions. On the basis of the above work, the dependence of fluorescent spectra on temperature was studied. It turned out that, not only the excitation spectra appeared red shift with increasing temperature, but also the dependence of the near infrared fluorescent intensity on temperature is fitting with a linear function. It might be served as a promising phosphor for temperature sensor device.

Study on UV Excitation Properties of Y2O3:Ln3+ (Ln = Eu3+ or Tb3+) Luminescent Nanomaterials

2008 ◽  
Vol 8 (3) ◽  
pp. 1443-1448 ◽  
Author(s):  
Qingyu Meng ◽  
Baojiu Chen ◽  
Xiaoxia Zhao ◽  
Xiaojun Wang ◽  
Wu Xu
Keyword(s):  
Particle Size ◽  
Charge Transfer ◽  
Charge Transfer Band ◽  
Emission Spectra ◽  
X Ray Diffraction ◽  
Bulk Materials ◽  
Excitation Spectra ◽  
X Ray ◽  
Long Wavelength ◽  
Uv Excitation

Y2O3:Ln3+ (Ln = Eu or Tb) nanocrystals with different Ln3+ doping concentrations and average sizes were prepared by chemical self-combustion. The corresponding bulk materials with various doping concentrations were obtained by annealing the nanomaterials at high temperature. The emission spectra, excitation spectra, and X-ray diffraction spectra were used in this study. It was found that the charge transfer band of Y2O3:Eu3+ red-shifted as particle size decreased, and the charge transfer band in the 5-nm particles obviously broadened toward the long wavelength. It was also found that the profile of excitation spectra corresponding to the 4f5d (4f8 → 4f75d1) transition changed a lot with the variation of the particle size. The dependence of the excitation spectra of Y2O3:Ln3+ on particle size was investigated.

Red and Green Phosphors Glow on the Basis of Oxide Glass-Ceramics Doped with Eu3+ and Tb3+

2015 ◽  
Vol 670 ◽  
pp. 107-112 ◽  
Author(s):  
Seseg Yu. Tsyretarova ◽  
Nina M. Kozhevnikova ◽  
Nina S. Ereminа ◽  
Gennady M. Mokrousov
Keyword(s):  
Emission Spectrum ◽  
Glass Ceramic ◽  
Charge Transfer Band ◽  
Broad Band ◽  
Glass Ceramics ◽  
Green Emission ◽  
Luminescent Properties ◽  
Inorganic Materials ◽  
Oxide Glass ◽  
Excitation Spectra

Glass-ceramics phosphors were obtained by the introduction of the crystalline phase NaMg3Sc (MoO4)5:Eu3+,Tb3+ in the glass composition 8SiO2-20B2O3-5Lu2O3-31Bi2O3-36ZnO. The properties were characterized by X-ray diffraction (XRD), photoluminescence (PL) and photoluminescent excitation spectra (PLE). The XRD patterns were indicated NaMg3Sc (MoO4)5:Eu3+,Tb3+ crystallize well with the novel structure type and were assigned to the triclinic phase (space group PĪ, Z = 6). Glass-ceramic phosphors are well-known and promising as solid electrolytes, laser, luminescent and other inorganic materials. Luminescent properties of the phosphors are performed at room temperature. The excitation spectra of Eu-doped phosphor present strong absorption at 300 nm and the sharp peaks in the 350-500 nm range. Under the 394 nm excitation, intense red emission peak at 616 nm corresponding to 5D0→7F2 transition of Eu3+ is observed in the emission spectrum. The luminescence property indicates that the local symmetry of Eu3+ ion has no inversion center. The excitation spectra of Tb-doped phosphor by monitoring wavelength at 546 nm shows the intense broad band from 260 to 420 nm and the line at 234 nm, which is mainly attributed to charge-transfer band transition in MoO42- group, indicating the existence of energy transfer from MoO42- to Tb3+ in the Tb3+:glass-ceramic. The measured emission spectrum of Tb-doped phosphor has intense green emission at 546 nm corresponding to 5D4→7F5 transition of Tb3+, with λex=368 nm. The as-prepared phosphors may find potential applications in the field such as color displays, light-emitting diodes (LEDs) and optoelectronic devices.

A Novel Phenomenon of Energy Transfer in Cd1-XZnxSiO3 : 0.01 Mn2+ Phosphor

2012 ◽  
Vol 549 ◽  
pp. 487-490 ◽  
Author(s):  
Xin Mu Zhou ◽  
Yong Xiu Li
Keyword(s):  
Energy Transfer ◽  
Ultraviolet Light ◽  
Sol Gel ◽  
Emission Spectra ◽  
Luminescent Properties ◽  
Emission Peak ◽  
Red Shift ◽  
Excitation Spectra ◽  
Gel Method ◽  
Sol Gel Method

Cd1-xZnxSiO3:0.01 Mn2+phosphor was synthesized by sol-gel method. It was characterized by excitation, emission spectra and XRD. The luminescent properties show the phenomenon of energy transfer from the tetrahedral coordinated Mn2+ion to the octahedral coordinated Mn2+ion after exciting by ultraviolet light, which boost the performance of the phosphor. With the increasing of Zn2+in Cd1-xZnxSiO3:0.01 Mn2+phosphor, it was observed the excitation spectra broadened and a red shift in the emission spectra, which emission peak moved from 580nm to 589nm.

scholarly journals Optimized Loading of TiO2 Nanoparticles into Electrospun Polyacrylonitrile and Cellulose Acetate Polymer Fibers

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Sibongile C. Nkabinde ◽  
Makwena J. Moloto ◽  
Kgabo P. Matabola
Keyword(s):  
Cellulose Acetate ◽  
Anatase Phase ◽  
Sol Gel ◽  
Polymer Concentration ◽  
Emission Spectra ◽  
Average Diameter ◽  
Xrd Analysis ◽  
Polymer Fibers ◽  
Electrospinning Technique ◽  
Calcination Temperatures

Polyacrylonitrile (PAN), cellulose acetate (CA), PAN-TiO2, and CA-TiO2 nanofibers were prepared using the electrospinning technique under varying the loading of the TiO2 nanoparticles. The latter TiO2 nanoparticles were prepared using the sol-gel method by varying the calcination temperatures. The absorption and emission spectra illustrated the formation of TiO2 nanoparticles with an increase in absorption band edges with smaller particles. The TEM results showed the spherical morphology of the nanoparticles calcined at 500°C with an average diameter of 12.2±3.3 nm. XRD analysis revealed anatase phase as the dominant crystalline phase of the nanoparticles. TiO2 nanoparticle loadings of 0.2 and 0.4 wt% were incorporated into 16 wt% CA solutions while 1, 2, and 3 wt% of TiO2 nanoparticles were incorporated into 10 wt% PAN solutions. The SEM results illustrated the lowering in diameter and morphology of the nanofibers upon incorporation of nanoparticles. Their respective average diameters are 220, 338, 181, and 250 nm for PAN, CA, PAN-TiO2, and CA-TiO2 polymer fibers, respectively. The morphology of the nanofibers improved while the diameter increased with an increase in polymer concentration. Different loadings of TiO2 nanoparticles improved the electrospinnability and morphology and further decreased the size of the nanofibers. FTIR spectroscopy signifies the formation of nanocomposites and the presence of TiO2 nanoparticles which corresponded to the Ti-O stretching and Ti-O-Ti bands on the FTIR spectra.

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