scholarly journals Photoluminescent Spectra of Nd3+Codoped CaAl2O4:Eu2+Blue Phosphor

2007 ◽  
Vol 2007 ◽  
pp. 1-4 ◽  
Author(s):  
Hojin Ryu ◽  
K. S. Bartwal
Keyword(s):  
Electron Microscopy ◽  
Emission Spectra ◽  
Solid State Reaction Method ◽  
X Ray Diffraction ◽  
Phosphor Material ◽  
Long Afterglow ◽  
Blue Phosphor ◽  
Transmission Electron ◽  
Ion Doping ◽  
Synthesized Materials

Phosphor material CaAl2O4:Eu2+codoped with varying concentrations ofNd3+was prepared by solid-state reaction method. Prepared materials with 1 mol%Eu2+andNd3+(0.5 to 5 mol%) show high brightness and long persistent luminescence. The phase and crystallinity of the synthesized materials were investigated by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Photoluminescence excitation and emission spectra were taken to investigate the luminescence characteristics. Broadband UV excited luminescence of the CaAl2O4:Eu2+,Nd3+was observed in the blue region (λmax= 440 nm) due to transitions from4f 6 5d1to the4f 7configuration of theEu2+ion. TheNd3+ion doping in the phosphor generates deep traps which result in long afterglow phosphorescence.

scholarly journals Synthesis of Novel YbxSb2 − xTe3Hexagonal Nanoplates: Investigation of Their Physical, Structural, and Photocatalytic Properties

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Younes Hanifehpour ◽  
Sang Woo Joo
Keyword(s):  
Electron Microscopy ◽  
Emission Spectra ◽  
Hydrothermal Condition ◽  
X Ray Diffraction ◽  
Dopant Content ◽  
Transmission Electron ◽  
Intensity Changes ◽  
Diffraction Patterns ◽  
Green Solution ◽  
Microscopy Images

Yb-doped Sb2Te3nanomaterials were synthesized by a coreduction method in hydrothermal condition. Powder X-ray diffraction patterns indicate that theYbxSb2−xTe3crystals (x=0.00–0.05) are isostructural with Sb2Te3. The cell parameteradecreases forYbxSb2−xTe3compounds upon increasing the dopant content (x), whilecincreases. Scanning electron microscopy and transmission electron microscopy images show that doping of Yb3+ions in the lattice of Sb2Te3produces different morphology. The electrical conductivity of Yb-doped Sb2Te3is higher than the pure Sb2Te3and increases with temperature. By increasing concentration of the Yb3+ions, the absorption spectrum of Sb2Te3shows red shifts and some intensity changes. In addition to the characteristic red emission peaks of Sb2Te3, emission spectra of doped materials show other emission bands originating fromf-ftransitions of the Yb3+ions. The photocatalytic performance of as-synthesized nanoparticles was investigated towards the decolorization of Malachite Green solution under visible light irradiation.

Synthesis and upconversion luminescence properties of CaF2:Yb3+,Er3+ nanoparticles obtained from SBA-15 template

2010 ◽  
Vol 25 (10) ◽  
pp. 2035-2041 ◽  
Author(s):  
Zhiguo Xia ◽  
Peng Du
Keyword(s):  
Electron Microscopy ◽  
Upconversion Luminescence ◽  
Emission Spectra ◽  
Average Diameter ◽  
Cubic Phase ◽  
Pumping Power ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
X Ray ◽  
Transmission Electron

CaF2:Yb3+,Er3+ upconversion (UC) luminescence nanoparticles have been synthesized using mesoporous silica (SBA-15) as a hard template. The samples were characterized by x-ray diffraction, Fourier transform infrared spectra, field-emission scanning electron microscopy, transmission electron microscopy, and UC emission spectra, respectively. Highly crystalline cubic phase CaF2:Yb3+,Er3+ nanoparticles are uniformly distributed with an average diameter of about 40–50 nm, and the formation process is also demonstrated. The UC fluorescence has been realized in the as-prepared CaF2:Yb3+,Er3+ nanoparticles on 980-nm excitation. The UC emission transitions for 4F9/2–4I15/2 (red), 2H11/2–4I15/2 (green), 4S3/2–4I15/2 (green), and 2H9/2–4I15/2 (violet) in the Yb3+/Er3+ codoped CaF2 nanoparticles depending on pumping power and temperature have been discussed. The UC mechanism, especially the origin on the temperature-dependent UC emission intensities ratio between 2H11/2 and 4S3/2 levels, have been proposed.

Thermo, Photo and Mechanoluminescence Studies of Eu3+ Doped Y4Al2O9 Phosphors

2018 ◽  
pp. 389-414
Author(s):  
Shubha Tripathi ◽  
Manish Kumar Mishra ◽  
Vikas Kumar Jain ◽  
Ratnesh Tiwari ◽  
Neha Dubey
Keyword(s):  
Electron Microscopy ◽  
Solid State Reaction Method ◽  
Electric Dipole Transition ◽  
Dipole Transition ◽  
Rare Earth Ions ◽  
X Ray Diffraction ◽  
Excitation Spectra ◽  
Tem Analysis ◽  
Europium Ion ◽  
Transmission Electron

The chapter reports synthesis and characterization of europium-doped Y4Al2O9 phosphor for display and dosimetric applications. The europium-activated Y4Al2O9 (YAM) phosphor is synthesized via solid state reaction method. Synthesized phosphors were characterized by powder x-ray diffraction (PXRD) techniques, scanning electron microscopy (SEM) technique, and transmission electron microscopy (TEM) technique. Particle size calculated from TEM analysis and crystallite size was calculated by Scherer's formula. All synthesized phosphor for different concentration of europium ion were studied by photo, thermo, and mechanoluminescence study. It is found that for photoluminescence analysis of Eu3+ doped phosphor has prominent spectra in red region and electric dipole transition (5D0 → 7F2) dominant over the magnetic dipole transition (5D0 → 7F1) due to non-centro symmetry between rare earth ions. Broad excitation spectra found for photoluminescence study.

Upcycling of Polystyrene Waste Plastics to High Value Carbon by Thermal Decomposition

2021 ◽  
Vol 897 ◽  
pp. 103-108
Author(s):  
Kenneth Mensah ◽  
Hatem Mahmoud ◽  
Manabu Fujii ◽  
Hassan Shokry
Keyword(s):  
Electron Microscopy ◽  
Thermal Decomposition ◽  
Waste Plastics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Environmental Threats ◽  
Transmission Electron ◽  
Different Temperatures ◽  
Polystyrene Waste ◽  
Synthesized Materials

Globally, the adverse environmental impact of waste plastics is of increasing concern. Most plastics are naturally non-degradable, thus imposes serious environmental threats, especially, to marine life. Upcycling such waste into valuable contents is an effective approach to managing waste plastics. In this study, graphene is synthesized from waste polystyrene (PS) by thermal decomposition at different temperatures (500, 600, 700, 800, 900 and 1000 °C) for two hours reaction time in a stainless steel autoclave. The synthesized materials are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Energy-disperse X-ray analysis (EDS) and surface area by using Brunauer–Emmett–Teller (BET). The yield of the product materials was investigated and optimized against the temperature. The synthesized graphene is considered a promising material for many applications, especially in environmental applications.

The Fabrication of One-Dimensional BaAl12O19:Mn2+ Phosphors by Electrospinning Method

2016 ◽  
Vol 852 ◽  
pp. 565-572 ◽  
Author(s):  
Qi Zheng Dong ◽  
Ling He ◽  
Wen Sheng Li ◽  
Wei Min Sun
Keyword(s):  
Electron Microscopy ◽  
Ph Value ◽  
Solid State Reaction Method ◽  
X Ray Diffraction ◽  
One Dimensional ◽  
Electrostatic Spinning ◽  
Calcination Temperatures ◽  
Transmission Electron ◽  
Good Crystallinity ◽  
Electrospinning Method

One-dimensional BaAl12O19:Mn2+ nanofibers were fabricated by electrostatic spinning method. The effects of some factors on the product preparation were investigated, such as the pH value of precursors; the proportion of citric acid; calcination temperatures, and then the optimal synthetic conditions was obtained. The calcination temperatures of optimal sample is only 1100 °C, less about 400 °C than that of the traditional solid state reaction method. X-ray diffraction, scanning electron microscopy, transmission electron microscopy and photoluminescence spectroscopy were adopted to detect the structure, grain size, morphology and optical properties of the nanofibers, respectively. The fiber samples with good crystallinity consist of a great quantity of nanoparticles. The size of each nanoparticle is below 50 nm and the fiber diameter is about 400 nm. Possible formation process of the nanofibers by electrostatic spinning was also discussed.

scholarly journals Optical Properties of Blue Phosphor

2009 ◽  
Vol 2009 ◽  
pp. 1-8 ◽  
Author(s):  
Mourad Derbal ◽  
Lakhdar Guerbous ◽  
Ouadjaout Djamel ◽  
Chaminade Jean Pierre ◽  
Mohyddine Kadi-Hanifi
Keyword(s):  
Blue Emission ◽  
Emission Spectra ◽  
Solid State Reaction Method ◽  
Photoluminescence Excitation ◽  
X Ray Diffraction ◽  
Reaction Method ◽  
X Ray ◽  
Blue Phosphor ◽  
Emission Transition ◽  
Scanning Electron

(, 0.5, 1, 5, and 10 at.%) polycrystalline powders blue phosphors were prepared via the classical solid-state reaction method. X-ray diffraction (XRD), scanning electron microscope (SEM), photoluminescence excitation, and emission spectra were used to characterize phosphors. By analyzing the excitation and emission spectra of samples, the result indicates that there exists the energy transfer only from the group to the energy level of ion. On the other hand, the influence of the thulium concentration on the blue emission transition and and the emission of group are investigated.

BiVO4/MIL-101 composite having the synergistically enhanced visible light photocatalytic activity

RSC Advances ◽  
2015 ◽  
Vol 5 (54) ◽  
pp. 43473-43479 ◽  
Author(s):  
Yanli Xu ◽  
Mengmeng Lv ◽  
Hanbiao Yang ◽  
Qi Chen ◽  
Xueting Liu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Photocatalytic Activity ◽  
Thermogravimetric Analysis ◽  
Diffuse Reflectance ◽  
Emission Spectra ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Visible Light Photocatalytic

The BiVO4/MIL-101 composite and pure materials were characterized by X-ray diffraction, transmission electron microscopy, thermogravimetric analysis, UV-vis diffuse reflectance absorption spectra and photoluminescence emission spectra.

scholarly journals Effect of RGO-Y2O3 and RGO-Y2O3:Cr3+ nanocomposite sensor for dopamine

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
J. K. Shashikumara ◽  
Bhimanagouda Kalaburgi ◽  
B. E. Kumara Swamy ◽  
H. Nagabhushana ◽  
S. C. Sharma ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Emission Spectra ◽  
Modified Electrodes ◽  
Current Response ◽  
Carbon Paste ◽  
X Ray Diffraction ◽  
X Ray ◽  
Carbon Paste Electrodes ◽  
Transmission Electron ◽  
Voltammetric Detection

AbstractThe RGO-Y2O3 and RGO-Y2O3: Cr3+ (5 mol %) nanocomposite (NC) synthesized by hydrothermal technique. The structure and morphology of the synthesized NCs were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Y2O3:Cr3+ displays spherical-shaped particles. Conversely, the surface of the RGO displays a wrinkly texture connecting with the existence of flexible and ultrathin graphene sheets. The photoluminescence (PL) emission spectra showed series of sharp peaks at 490, 591, and 687 nm which corresponding to 4F9/2 → 6H15/2, 4F9/2 → 6H13/2, and 4F9/2 → 6H11/2 transitions and lies in the blue, orange, and red region. The prepared NCs were used for the preparation of modified carbon paste electrodes (MCPE) in the electrochemical detection of dopamine (DA) at pH 7.4. Both modified electrodes provide a good current response towards voltammetric detection of DA. Doping is an effective method to improve the conductivity of Y2O3:Cr3+ and developed a method for the sensor used in analytical applications.

scholarly journals Synthesis, Luminescent Properties and White LED Fabrication of Sm3+ Doped Lu2WMoO9

Coatings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 403
Author(s):  
Zijun Chen ◽  
Huiyi Xu ◽  
Chunyan Cao ◽  
Xiaoting Chen ◽  
Min Zhang ◽  
...  
Keyword(s):  
Emission Spectra ◽  
Luminescent Properties ◽  
Solid State Reaction Method ◽  
White Led ◽  
X Ray Diffraction ◽  
Nonradiative Relaxation ◽  
Temperature Dependent ◽  
X Ray ◽  
Xrd Patterns ◽  
Synthesized Materials

In this paper, Sm3+ doped Lu2W0.5Mo0.5O6, Lu2WMoO9, and Lu2(W0.5Mo0.5O4)3 materials were synthesized by using a two-step solid-state reaction method. The synthesized materials were characterized by X-ray diffraction (XRD) patterns, field emission scanning electronic micrograph (FE-SEM) pictures, photoluminescence (PL) excitation and emission spectra, and temperature-dependent emission intensities. Orange-reddish light could be observed from the phosphors under ultraviolet (UV) 365 nm light. The Sm3+ doped Lu2WMoO9 had enhanced PL intensities compared to the other two materials. The excitation, the energy transfer, the nonradiative relaxation, and the emission processes were illustrated by using schematic diagrams of Sm3+ in Lu2MoWO9. The optimal Sm3+ doping concentration was explored in the enhancing luminescence of Lu2WMoO9. By combing the Sm3+ doped Lu2WMoO9 to UV 365 nm chips, near white lighting emitting diode (W-LED) were obtained. The phosphor can be used in single phosphor-based UV W-LEDs.

scholarly journals Effect of RGO-Y2O3 and RGO-Y2O3:Cr3+ Nano Composite Sensor for Dopamine

2021 ◽  
Author(s):  
J Shashikumar ◽  
Bheenama Patil ◽  
B E KUMARA SWAMY ◽  
H Nagabhushana ◽  
S Sharma ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Emission Spectra ◽  
Modified Electrodes ◽  
Carbon Paste ◽  
X Ray Diffraction ◽  
Nano Composite ◽  
X Ray ◽  
Carbon Paste Electrodes ◽  
Transmission Electron ◽  
Good Electrocatalytic Activity

Abstract The RGO-Y2O3 and RGO-Y2O3: Cr3+ (5 mol %) nanocomposite (NC) synthesized a simple hydrothermal technique. The structure and morphology of the synthesized NCs were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Y2O3:Cr3+ display spherical shaped particles. Conversely, the surface of the RGO displays a wrinkly texture connecting with the existence of flexible and ultrathin graphene sheets. The photoluminescence (PL) emission spectra showed series of sharp peaks at 490, 591, and 687 nm which corresponding to 4F9/2→6H15/2, 4F9/2→6H13/2, and 4F9/2→6H11/2 transitions and lies in the blue, orange, and red region. The prepared NCs were used for the preparation of modified carbon paste electrodes (MCPE) in the electrochemical detection of dopamine (DA) at pH 7.4. Both modified electrodes provide a good electrocatalytic activity for the voltametric detection of DA. Doping is an effective method to improve the conductivity of Y2O3:Cr3+ and developed a method for the sensor used in analytical applications.

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