scholarly journals Implication of Mn concentration on the properties of cerium oxide thin films

2020 ◽  
Vol 1 (1) ◽  
pp. 1-9
Author(s):  
Suresh R ◽  
◽  
Thirumal Valavan K ◽  
Justin Paul M ◽  
Indira Priyadharshini T ◽  
...  
Keyword(s):  
Cerium Oxide ◽  
Energy Levels ◽  
Blue Emission ◽  
Emission Spectra ◽  
Green Emission ◽  
Fluorite Structure ◽  
Crystal Defects ◽  
Energy Bands ◽  
Ft Ir ◽  
Mn Concentration

Uniform and adhesive Manganese doped cerium oxide (MDC) films are successfully deposited by Nebulizer Spray Pyrolysis (NSP) technique. The MDC films are characterized by XRD, FT-IR, UV-ViS, PL and I-V analysis. X-ray diffraction peaks reveal the single-phase polycrystalline cubic fluorite structure with preferential orientation along (2 0 0) direction. The broad bands observed at 695, 659, 538 and 517 cm-1 are due to the envelope of (Ce=O) symmetric, asymmetric terminal stretching and phonon band of metal oxide (Ce-O) network from FT-IR spectra. The transmittance decreases with Mn concentration due to the increase in scattering of photon by crystal defects created by doping and lower ionic size of Mn. The electrons in the outer orbits have travelled to the higher energy levels and have occupied vacant positions in energy bands. Some of the NBE emission and green emission peaks are vanished at higher doping level of Mn. The occurrence of a strong and broad blue emission peak at 15% for MDC films has been confirmed from emission spectra.

scholarly journals SrAl2O4:Eu2+(,Dy3+) Nanosized Particles: Synthesis and Interpretation of Temperature-Dependent Optical Properties

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Huayna Terraschke ◽  
Markus Suta ◽  
Matthias Adlung ◽  
Samira Mammadova ◽  
Nahida Musayeva ◽  
...  
Keyword(s):  
Emission Band ◽  
Blue Emission ◽  
Emission Spectra ◽  
Green Emission ◽  
Spectroscopic Properties ◽  
Host Lattice ◽  
Nanosized Particles ◽  
Temperature Dependent ◽  
Excitation Spectra ◽  
Blue Emission Band

SrAl2O4nanosized particles (NPs) undoped as well as doped with Eu2+and Dy3+were prepared by combustion synthesis for the discussion of their intensively debated spectroscopic properties. Emission spectra of SrAl2O4:Eu2+(,Dy3+) NPs are composed by a green band at 19 230 cm−1(520 nm) at room temperature, assigned to anomalous luminescence originated by Eu2+in this host lattice. At low temperatures, a blue emission band at 22 520 cm−1(444 nm) is observed. Contrary to most of the interpretations provided in the literature, we assign this blue emission band very reliably to a normal 4f6(7FJ)5d(t2g)→4f7(8S7/2) transition of Eu2+substituting the Sr2+sites. This can be justified by the presence of a fine structure in the excitation spectra due to the different7FJlevels (J=0⋯6) of the 4f6core. Moreover, Fano antiresonances with the6IJ(J=9/2,7/2) levels could be observed. In addition, the Stokes shifts (ΔES=1980 cm−1and 5 270 cm−1for the blue and green emission, resp.), the Huang-Rhys parameters ofS=2.5and 6, and the average phonon energies ofħω=480 cm-1and 470 cm−1coupled with the electronic states could be reliably determined.

scholarly journals Fe(III) doped carbon nanodots with intense green photoluminescence and dispersion medium dependent emission

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Corneliu Sergiu Stan ◽  
Adina Coroabă ◽  
Elena Laura Ursu ◽  
Marius Sebastian Secula ◽  
Bogdan C. Simionescu
Keyword(s):  
Steady State ◽  
Polymer Matrix ◽  
Thermal Processing ◽  
Dispersion Medium ◽  
Blue Emission ◽  
Green Emission ◽  
Carbon Nanodots ◽  
Ft Ir ◽  
Green Photoluminescence ◽  
Deep Green

AbstractThe preparation and investigation of Fe(III) doped carbon nanodots (CNDs) with intense green photoluminescence and emission dependence on the dispersion medium are reported. Their unusual photoluminescence is especially highlighted in water where the initial blue emission is gradually shifted to intense deep green, while in other common solvents (chloroform, acetone etc.) this behavior has not been observed. Through embedding in a polymer matrix (e.g., PVA) the color transition becomes reversible and dependent on water content, ranging from a full blue emission, when completely dried, to an intense green emission, when wetted. The preparation path of the Fe(III) doped CNDs undergoes two main stages involving the initial obtaining of Fe(III)–N–Hydroxyphthalimide complex and then a thermal processing through controlled pyrolysis. Morphostructural investigations of the prepared Fe(III) doped CNDs were performed through TG, FT-IR, XPS, DLS, TEM and AFM techniques whereas absolute PLQY, steady state and lifetime fluorescence were used to highlight their luminescence properties. The results issued from structural and fluorescence investigations bring new insights on the particular mechanisms involved in CNDs photoluminescence, a topic still open to debate.

scholarly journals Strontium Aluminate-Based Long Afterglow PP Composites: Phosphorescence, Thermal, and Mechanical Characteristics

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1373
Author(s):  
Anesh Manjaly Poulose ◽  
Arfat Anis ◽  
Hamid Shaikh ◽  
Abdullah Alhamidi ◽  
Nadavala Siva Kumar ◽  
...  
Keyword(s):  
Blue Emission ◽  
Emission Spectra ◽  
Green Emission ◽  
Attenuated Total Reflection ◽  
Strontium Aluminate ◽  
Scanning Calorimetry ◽  
Melt Mixing ◽  
Long Afterglow ◽  
Poly Ethylene ◽  
The Impact

A tremendous potential has been observed in the designing of long afterglow materials for sensing, bioimaging, and encryption applications. In this study, two different strontium aluminate-based luminescent materials; SrAl2O4: Eu, Dy (S1), and Sr4Al14O25: Eu, Dy (S2) were melt-mixed with polypropylene (PP) matrix, and the phosphorescence properties were evaluated. After excitation at 320 nm, the PP/S1 composite exhibited a green emission and the PP/S2 generated a blue emission at 520 nm and 495 nm, respectively. The emission spectra intensity increased by increasing the content of these luminescent fillers. The attenuated total reflection-Fourier transform infrared (ATR-FTIR) experiments show that no chemical reaction occurred during the melt-mixing process. The differential scanning calorimetry (DSC) results revealed that the total crystallinity of the composites reduced by increasing the amount of the fillers; however, no changes in the temperature of melting (Tm) and crystallization (Tc) of PP were observed. Both fillers improved the impact strength of the composites, but the tensile strength (TS) and modulus (TM) decreased. Poly (ethylene glycol) dimethyl ether (P) plasticizer was used to improve the filler-matrix interaction and its dispersion; nevertheless, it adversely affected the intensity of the luminescence emissions.

A new stepped tetranuclear copper(II) complex: synthesis, crystal structure and photoluminescence properties

2017 ◽  
Vol 73 (5) ◽  
pp. 393-398 ◽  
Author(s):  
Elif Gungor
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Uv Light ◽  
Visible Region ◽  
Blue Emission ◽  
Green Emission ◽  
Photoluminescence Properties ◽  
X Ray Diffraction ◽  
Vis Spectroscopy ◽  
Ft Ir

Binuclear and tetranuclear copper(II) complexes are of interest because of their structural, magnetic and photoluminescence properties. Of the several important configurations of tetranuclear copper(II) complexes, there are limited reports on the crystal structures and solid-state photoluminescence properties of `stepped' tetranuclear copper(II) complexes. A new CuII complex, namely bis{μ3-3-[(4-methoxy-2-oxidobenzylidene)amino]propanolato}bis{μ2-3-[(4-methoxy-2-oxidobenzylidene)amino]propanolato}tetracopper(II), [Cu4(C11H13NO3)4], has been synthesized and characterized using elemental analysis, FT–IR, solid-state UV–Vis spectroscopy and single-crystal X-ray diffraction. The crystal structure determination shows that the complex is a stepped tetranuclear structure consisting of two dinuclear [Cu2(L)2] units {L is 3-[(4-methoxy-2-oxidobenzylidene)amino]propanolate}. The two terminal CuII atoms are four-coordinated in square-planar environments, while the two central CuII atoms are five-coordinated in square-pyramidal environments. The solid-state photoluminescence properties of both the complex and 3-[(2-hydroxy-4-methoxybenzylidene)amino]propanol (H2 L) have been investigated at room temperature in the visible region. When the complex and H2 L are excited under UV light at 349 nm, the complex displays a strong blue emission at 469 nm and H2 L displays a green emission at 515 nm.

Polyacrylic Acid Modified Cerium Oxide Nanoparticles: Synthesis and Characterization as a Peroxidase Mimic for Non-Enzymatic H2O2 Sensor

2020 ◽  
Vol 16 (5) ◽  
pp. 816-828
Author(s):  
Gurdeep Rattu ◽  
Nishtha Khansili ◽  
Prayaga M. Krishna
Keyword(s):  
Hydrogen Peroxide ◽  
Cerium Oxide ◽  
Polyacrylic Acid ◽  
Spectroscopic Analysis ◽  
Cerium Oxide Nanoparticles ◽  
Oxide Nanoparticles ◽  
Peroxidase Mimic ◽  
Ft Ir ◽  
H2o2 Sensing ◽  
Fluorescence Spectrometer

Background: Cerium oxide nanoparticles (nanoceria) are efficient free-radical scavengers due to their dual valence state and thus exhibit optical and catalytic properties. Therefore, the main purpose of this work was to understand the peroxidase mimic activity of polymer-stabilized nanoceria for enzyme-less H2O2 sensing by fluorescence spectrometer. Objective: This research revealed the development of fluorescence hydrogen peroxide nanosensor based on the peroxidase-like activity of polyacrylic acid stabilized nanoceria (PAA-CeO2 Nps). Methods: PAA-CeO2 Nps were synthesized by simple cross-linking reaction at a low temperature and characterized by XRD, SEM, Zeta potential, TGA, FT-IR and UV-VIS spectroscopic analysis. H2O2 sensing was performed by a fluorescence spectrometer. Results:: The synthesized polymer nanocomposite was characterized by XRD, SEM, TGA, FT-IR and UV-VIS spectroscopic analysis. The XRD diffraction patterns confirmed the polycrystalline nature and SEM micrograph showed nanoparticles having hexagonal symmetry and crystallite size of 32 nm. The broad peak of Ce–O bond appeared at 508 cm-1. UV-VIS measurements revealed a welldefined absorbance peak around 315 nm and an optical band-gap of 3.17 eV. As synthesized PAACeO2 Nps effectively catalysed the decomposition of hydrogen peroxide (H2O2) into hydroxyl radicals. Then terephthalic acid was oxidized by hydroxyl radical to form a highly fluorescent product. Under optimized conditions, the linear range for determination of hydrogen peroxide was 0.01 - 0.2 mM with a limit of detection (LOD) of 1.2 μM. Conclusion: The proposed method is ideally suited for the sensing of H2O2 at a low cost and this detection system enabled the sensing of analytes (sugars), which can enzymatically generate hydrogen peroxide.

scholarly journals Polymer Thermal Treatment Production of Cerium Doped Willemite Nanoparticles: An Analysis of Structure, Energy Band Gap and Luminescence Properties

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1118
Author(s):  
Ibrahim Mustapha Alibe ◽  
Khamirul Amin Matori ◽  
Mohd Hafiz Mohd Zaid ◽  
Salisu Nasir ◽  
Ali Mustapha Alibe ◽  
...  
Keyword(s):  
Solid State ◽  
Thermal Treatment ◽  
Band Gap ◽  
Optical Band Gap ◽  
Dopant Concentration ◽  
Blue Emission ◽  
Green Emission ◽  
Band Gap Energy ◽  
Solid State Lighting ◽  
Gap Energy

The contemporary market needs for enhanced solid–state lighting devices has led to an increased demand for the production of willemite based phosphors using low-cost techniques. In this study, Ce3+ doped willemite nanoparticles were fabricated using polymer thermal treatment method. The special effects of the calcination temperatures and the dopant concentration on the structural and optical properties of the material were thoroughly studied. The XRD analysis of the samples treated at 900 °C revealed the development and or materialization of the willemite phase. The increase in the dopant concentration causes an expansion of the lattice owing to the replacement of larger Ce3+ ions for smaller Zn2+ ions. Based on the FESEM and TEM micrographs, the nanoparticles size increases with the increase in the cerium ions. The mean particles sizes were estimated to be 23.61 nm at 1 mol% to 34.02 nm at 5 mol% of the cerium dopant. The optical band gap energy of the doped samples formed at 900 °C decreased precisely by 0.21 eV (i.e., 5.21 to 5.00 eV). The PL analysis of the doped samples exhibits a strong emission at 400 nm which is ascribed to the transition of an electron from localized Ce2f state to the valence band of O2p. The energy level of the Ce3+ ions affects the willemite crystal lattice, thus causing a decrease in the intensity of the green emission at 530 nm and the blue emission at 485 nm. The wide optical band gap energy of the willemite produced is expected to pave the way for exciting innovations in solid–state lighting applications.

Effect of UV Treatment on Optical Properties of Low-Density Polyethylene Films Doped with Eu(TTA)3phen Complex

2014 ◽  
Vol 895 ◽  
pp. 155-161
Author(s):  
M.I. Khairuldin ◽  
N.M.A. Aziz ◽  
N.M. Nashaain ◽  
S. Wedianti ◽  
I. Farehah ◽  
...  
Keyword(s):  
Optical Properties ◽  
Emission Spectra ◽  
Low Density Polyethylene ◽  
Rare Earth Complex ◽  
Low Density ◽  
Uv Treatment ◽  
Uv Spectrum ◽  
Light Manipulation ◽  
Emission Transition ◽  
Ft Ir

Low-Density Polyethylene (LDPE) films doped with Eu (TTA)3phen complex (TTA=2-thenoyltrifluoroacetone, phen=1,10-phenanthroline) were fabricated by hot-blowing technique for thickness of 100 μm. The films were doped with 0.1 % of Eu (TTA)3phen to the total weight of LDPE and exposed to UV irradiation from deuterium lamp for 5, 10, 20, 40 and 60 hours to investigate the effect of its optical properties. The films were characterized by Spectrofluorometer, UV/VIS Spectrophotometer and FT-IR Spectrometer to measure their emission spectra, lifetimes, transmission transparency and chemical bonding. Photoluminescence of the room-temperature Eu (TTA)3phen doped films consist of typical Eu3+emission transition lines with hypersensitive5D07F2emission band at 610 nm. After 20 hours UV treatment, the peak intensity dropped by 90 % and shortened the luminescent lifetimes from 0.654 ms to 0.305 ms. Longer UV treatment also has accelerated degradation in doped LDPE films shown by significant reducing in absorption peak of FTIR at 3395, 3186 and 1645 cm-1. The results would provide a mechanism to improve the lifetime of the LDPE by utilizing the light-manipulation property of Eu (TTA)3phen complex to absorb UV spectrum and covert into red emission.Keywords: LDPE, rare-earth complex, photoluminescence

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