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Sample records for highly luminescent polymer

  1. Fabrication and spectroscopic studies on highly luminescent CdSe/CdS nanorod polymer composites

    NARCIS (Netherlands)

    Bomm, J.; Büchtemann, A.; Fiore, Angela; Manna, L.; Nelson, J.H.; Hill, D.; van Sark, W.G.J.H.M.

    2010-01-01

    Highly luminescent nanocomposites were prepared by incorporating CdSe/CdS core/shell nanorods into different polymer matrices. The resulting nanocomposites show high transparency of up to 93%. A photoluminescence quantum efficiency of 70% was obtained, with an optimum combination of nanorod (0.05 wt

  2. Luminescent lanthanide coordination polymers

    Energy Technology Data Exchange (ETDEWEB)

    Ma, L.; Evans, O.R.; Foxman, B.M.; Lin, W.

    1999-12-13

    One-dimensional lanthanide coordination polymers with the formula Ln(isonicotinate){sub 3}(H{sub 2}O){sub 2} (Ln = Ce, Pr, Nd, Sm, Eu, Tb; 1a-f) were synthesized by treating nitrate or perchlorate salts of Ln(III) with 4-pyridinecarboxaldehyde under hydro(solvo)thermal conditions. Single-crystal and powder X-ray diffraction studies indicate that these lanthanide coordination polymers adopt two different structures. While Ce(III), Pr(III), and Nd(III) complexes adopt a chain structure with alternating Ln-(carboxylate){sub 2}-Ln and Ln-(carboxylate){sub 4}-Ln linkages, Sm(III), Eu(III), and Tb(III) complexes have a doubly carboxylate-bridged infinite-chain structure with one chelating carboxylate group on each metal center. In both structures, the lanthanide centers also bind to two water molecules to yield an eight-coordinate, square antiprismatic geometry. The pyridine nitrogen atoms of the isonicotinate groups do not coordinate to the metal centers in these lanthanide(III) complexes; instead, they direct the formation of Ln(III) coordination polymers via hydrogen bonding with coordinated water molecules. Photoluminescence measurements show that Tb(isonicotinate){sub 3}(H{sub 2}O){sub 2} is highly emissive at room temperature with a quantum yield of {approximately}90%. These results indicate that highly luminescent lanthanide coordination polymers can be assembled using a combination of coordination and hydrogen bonds. Crystal data for 1a: monoclinic space group P2{sub 1}/c, a = 9.712(2) {angstrom}, b = 19.833(4) {angstrom}, c = 11.616(2) {angstrom}, {beta} = 111.89(3){degree}, Z = 4. Crystal data for 1f: monoclinic space group C2/c, a = 20.253(4) {angstrom}, b = 11.584(2) {angstrom}, c = 9.839(2) {angstrom}, {beta} = 115.64(3){degree}, Z = 8.

  3. Microwave synthesis of homogeneous and highly luminescent BCNO nanoparticles for the light emitting polymer materials

    Energy Technology Data Exchange (ETDEWEB)

    Iwasaki, Hideharu [Battery Materials Laboratory, Kurashiki Research Center, Kuraray Co., Ltd., 2045-1, Sakazu, Kurashiki, Okayama 710-0801 (Japan); Department of Chemical Engineering, Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi Hiroshima 739 8527 (Japan); Ogi, Takashi, E-mail: ogit@hiroshima-u.ac.jp [Department of Chemical Engineering, Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi Hiroshima 739 8527 (Japan); Iskandar, Ferry [Department of Physics, Institute of Technology Bandung, Ganesha 10, Bandung 40132, West Java (Indonesia); Aishima, Kana; Okuyama, Kikuo [Department of Chemical Engineering, Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi Hiroshima 739 8527 (Japan)

    2015-10-15

    Nano-sized boron carbon oxynitride (BCNO) phosphors around 50 nm containing no rare earth metal and free from color heterogeneity were synthesized from mixtures of boric acid, urea, and citric acid by microwave heating with substantially shorter reaction times and lower temperatures than in the conventional BCNO preparation method such as electric-furnace heating. The emission wavelength of the phosphors varied with the mixing ratio of raw materials and it was found that lowering the proportion of urea to boric acid or citric acid tended to increase the internal quantum yield and shorten the emission wavelength under excitation at 365 nm. It was also found for the first time that a light-emitting polymer could be synthesized from a mixture of the prepared BCNO nanoparticles and a polyvinyl alcohol. This polymer composite exhibited uniform dispersion and stabilization of the luminescence and had a high internal quantum yield of 54%, which was higher than that of the phosphor alone. - Highlights: • Nano-sized BCNO phosphor was synthesized via microwave heating. • BCNO nanophosphor has homogeneous and high luminescence. • Emission wavelength was tunable by changing the ratio of precursor components. • BCNO nanophosphor can be easily dispersed in a polyvinyl alcohol. • BCNO–polymer composite exhibited uniform high internal quantum yield.

  4. Refractive Index Tuning of Hybrid Materials for Highly Transmissive Luminescent Lanthanide Particle-Polymer Composites.

    Science.gov (United States)

    Kim, Paul; Li, Cheng; Riman, Richard E; Watkins, James

    2018-03-14

    High-refractive-index ZrO 2 nanoparticles were used to tailor the refractive index of a polymer matrix to match that of luminescent lanthanide-ion-doped (La 0.92 Yb 0.075 Er 0.005 F 3 ) light-emitting particles, thereby reducing scattering losses to yield highly transparent emissive composites. Photopolymerization of blends of an amine-modified poly(ether acrylate) oligomer and tailored quantities of ZrO 2 nanoparticles yielded optically transparent composites with tailored refractive indices between 1.49 and 1.69. By matching the refractive index of the matrix to that of La 0.92 Yb 0.075 Er 0.005 F 3 , composites with high transmittance (>85%) and low haze from the visible to infrared regions, bright 1530 nm optical emissions were achieved at solids loadings of La 0.92 Yb 0.075 Er 0.005 F 3 , ranging from 5 to 30 vol %. These optical results suggest that a hybrid matrix approach is a versatile strategy for the fabrication of functional luminescent optical composites of high transparency.

  5. Studies of positron induced luminescence from polymers

    International Nuclear Information System (INIS)

    Xu, J.; Hulett, L.D. Jr.; Lewis, T.A.; Tolk, N.H.

    1994-01-01

    Light emission from polymers (anthracene dissolved in polystryrene) induced by low-energy positrons and electrons has been studied. Results indicate a clear difference between optical emissions under positron and electron bombardment. The positron-induced luminescence spectrum is believed to be generated by both collisional and annihilation processes

  6. New polymers containing BF2-benzoylacetonate groups. Synthesis, luminescence, excimer and exciplex formation

    International Nuclear Information System (INIS)

    Fedorenko, Elena V.; Mirochnik, Anatolii G.; Beloliptsev, Anton Yu.

    2017-01-01

    In the present study, a new synthetic method for the functionalization of polystyrene (PS) and (styrene-methyl methacrylate) copolymer has been developed. Using the new method, polymers containing BF 2 -benzoylacetonate groups have been obtained through double acylation by acetic anhydride with boron trifluoride. Luminescence of the produced polymers in solutions and films has been studied. Quantum yields of polymer solution luminescence are significantly higher than those of the low-molecular-weight analog – boron difluoride benzoylacetonate. For the polymer, in which styrene fragments are separated by methyl methacrylate groups, at low concentrations of the polymer in solution one observes the monomer luminescence of BF 2 -benzoylacetonate groups, while at high concentrations – the excimer luminescence. In case of PS-based polymers, in which BF 2 -benzoylacetonate groups and phenyl rings are not separated, in diluted solutions one observes the fluorescence of the intramolecular exciplexes, while at the concentration increase – the luminescence of intermolecular exciplexes. The ability of excimer formation is responsible for the increased photostability of the produced polymers. - Highlights: •Polymers containing BF 2 -benzoylacetonate groups have been synthesized. •Luminescence of the produced polymers in solutions and films has been studied. •Formation of excimers and exciplexes in solution has been revealed. •Formation of excimers in films increases their photostability.

  7. New polymers containing BF{sub 2}-benzoylacetonate groups. Synthesis, luminescence, excimer and exciplex formation

    Energy Technology Data Exchange (ETDEWEB)

    Fedorenko, Elena V., E-mail: gev@ich.dvo.ru [Institute of Chemistry, Far Eastern Branch of the Russian Academy of Sciences, 159, Prosp. 100 letiya Vladivostoka, Vladivostok 690022 (Russian Federation); Mirochnik, Anatolii G.; Beloliptsev, Anton Yu. [Institute of Chemistry, Far Eastern Branch of the Russian Academy of Sciences, 159, Prosp. 100 letiya Vladivostoka, Vladivostok 690022 (Russian Federation)

    2017-05-15

    In the present study, a new synthetic method for the functionalization of polystyrene (PS) and (styrene-methyl methacrylate) copolymer has been developed. Using the new method, polymers containing BF{sub 2}-benzoylacetonate groups have been obtained through double acylation by acetic anhydride with boron trifluoride. Luminescence of the produced polymers in solutions and films has been studied. Quantum yields of polymer solution luminescence are significantly higher than those of the low-molecular-weight analog – boron difluoride benzoylacetonate. For the polymer, in which styrene fragments are separated by methyl methacrylate groups, at low concentrations of the polymer in solution one observes the monomer luminescence of BF{sub 2}-benzoylacetonate groups, while at high concentrations – the excimer luminescence. In case of PS-based polymers, in which BF{sub 2}-benzoylacetonate groups and phenyl rings are not separated, in diluted solutions one observes the fluorescence of the intramolecular exciplexes, while at the concentration increase – the luminescence of intermolecular exciplexes. The ability of excimer formation is responsible for the increased photostability of the produced polymers. - Highlights: •Polymers containing BF{sub 2}-benzoylacetonate groups have been synthesized. •Luminescence of the produced polymers in solutions and films has been studied. •Formation of excimers and exciplexes in solution has been revealed. •Formation of excimers in films increases their photostability.

  8. Luminescent Polymer Electrolyte Composites Using Silica Coated-Y2O3:Eu as Fillers

    Directory of Open Access Journals (Sweden)

    Mikrajuddin Abdullah

    2003-05-01

    Full Text Available Luminescent polymer electrolyte composites composed of silica coated Y2O3:Eu in polyethylene glycol (PEG matrix has been produced by initially synthesizing silica coated Y2O3:Eu and mixing with polyethylene glycol in a lithium salt solution. High luminescence intensity at round 600 nm contributed by electron transitions in Eu3+ (5D0 -> 7F0, 5D0 -> 7F1, and 5D0 -> 7F3 transitions were observed. The measured electrical conductivity was comparable to that reported for polymer electrolyte composites prepared using passive fillers (non luminescent. This approach is therefore promising for production of high intensity luminescent polymer electrolyte composites for use in development of hybrid battery/display.

  9. Novel Luminescent Multilayer Films Containing π-Conjugated Anionic Polymer with Electronic Microenvironment

    Directory of Open Access Journals (Sweden)

    Tianlei Wang

    2016-09-01

    Full Text Available Layered double hydroxides (LDHs, luminescent π-conjugated anionic polymer and montmorillonite (MMT were orderly assembled into luminescent multilayer films via layer-by-layer self-assembly method. The electronic microenvironment (EME, the structure of which is like a traditional capacitor, can be constructed by exfoliated LDHs or MMT nanosheets. In addition, the rigid inorganic laminated configuration can offer stable surroundings between the interlayers. As a result, we conclude that EME can extend the luminescent lifespans of multilayer films substantially, due to affecting relaxation times of π-conjugated anionic polymer. Consequently, because of the remarkable impact on better photoemission behaviors of luminescent π-conjugated anionic polymer, EME assembled by LDHs or MMT nanosheets have had high hopes attached to them. They are expected to have the potential for designing, constructing, and investigating novel light-emitting thin films.

  10. Selective high capacity adsorption of Congo red, luminescence and antibacterial assessment of two new cadmium(II) coordination polymers

    Science.gov (United States)

    Beheshti, Azizolla; Nozarian, Kimia; Ghamari, Narges; Mayer, Peter; Motamedi, Hossein

    2018-02-01

    Coordination polymers [CdCl(NCS)L]n (1) and {[Cd2I4(L)2]·H2O·DMF}n (2) (where L = 1, 1-(1,4-butanediyl)bis(1,3-dihydro-3-methyl-1H-imidazole- 2-thione)) were synthesized and structurally characterized. Compounds 1 and 2 both possess a tetrahedral arrangement with CdS2NCl and CdS2I2 cores, respectively. In these structures, the flexible thione ligands adopt a μ- bridging coordination mode to form 1D chains along the b-axis. The 1D chains are join together by C-H--Cl hydrogen bonds (in 1) and water molecules (in 2) to create a 2D supramolecular framework with an ABAB…packing mode. Remarkably, compounds 1 and 2 in particular polymer 1 exhibit excellent capacity to adsorb Congo red (CR) with high selectivity. The experimental data demonstrate that the mechanism of sorption process can be described by the Elovich and pseudo second order kinetic models for 1 and 2, respectively. Furthermore, the possible mechanism of CR absorption was investigated by UV-Vis and solid state fluorescence spectra for the title polymers. In addition, the antibacterial assessment of these compounds have also been studied.

  11. Oxide/polymer nanocomposites as new luminescent materials

    Science.gov (United States)

    Vollath, D.; Szabó, D. V.; Schlabach, S.

    2004-06-01

    It is demonstrated that nanocomposites, consisting of an electrically insulating oxide core and PMMA coating exhibit strong luminescence. This luminescence is connected to the interface, where PMMA is bond via a carboxylate bonding to the surface. In this case, luminescence is originated at the carbonyl group of the coating polymer. With decreasing particle size, this emission shows a blue shift, following a law inversely the ones found for quantum confinement systems. For semi-conducting oxides, such as ZnO, this interface related emission is found additionally to quantum confinement phenomena.

  12. Three luminescent d{sup 10} metal coordination polymers assembled from a semirigid V-shaped ligand with high selective detecting of Cu{sup 2+} ion and nitrobenzene

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Wei-Ping [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, Shaanxi Key Laboratory of Physico-Inorg. Chem., College of Chemistry & Materials Science, Northwest University, Xi’an 710069 (China); Institute of Functional Materials, College of Chemistry and Pharmaceutical Engineering, Sichuan University of Science & Engineering, Zigong 643000 (China); Liu, Ping; Liang, Yu-Tong; Cui, Lin; Xi, Zheng-Ping [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, Shaanxi Key Laboratory of Physico-Inorg. Chem., College of Chemistry & Materials Science, Northwest University, Xi’an 710069 (China); Wang, Yao-Yu, E-mail: wyaoyu@nwu.edu.cn [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, Shaanxi Key Laboratory of Physico-Inorg. Chem., College of Chemistry & Materials Science, Northwest University, Xi’an 710069 (China)

    2015-08-15

    Three 2D luminescent coordination polymers with helical frameworks, [ZnL{sub 2}]{sub n} (1) and ([ML{sub 2}]·(H{sub 2}O)){sub n} (M=Zn (2), Cd (3)) (HL=4-((2-methyl-1 H-imidazol-1-yl)methyl)benzoic acid), have been assembled under hydro(solvo)thermal conditions. Complex 1 is in chiral space group and displays a rare 2D→2D 2-fold parallel interpenetrated layer network with two types of chiral double helixes. Interestingly, the single crystal structure analyses indicate the coexistence of enantiomers la and 1b in one pot, while the bulk crystallization of 1 are racemic mixtures based on the CD measurement. 2 and 3 are isostructural, in the structure, there are two kinds of 2D chiral helical-layers which stack in an -ABAB- sequence leading to the overall structure are mesomer and achiral. All compounds display intense luminescence in solid state at room temperature with high chemical and thermal stability. More importantly, 1 has been successfully applied in the detection of Cu{sup 2+} ions in aqueous media and nitrobenzene and the probable detecting mechanism was also discussed. - Graphical abstract: Three luminescent d{sup 10} metal coordination polymers with helical-layer based on 4-((2-methyl-1H-imidazol-1-yl)methyl)benzoic acid have been obtained. Compound 1 shows high selective detecting for Cu{sup 2+} ion in aqueous and nitrobenzene. - Highlights: • Three coordination polymers with chiral helical-layer have been obtained. • 1 Can luminescent detect Cu{sup 2+} ion in aqueous media and nitrobenzene. • Racemic mixture or mesomer compounds can be obtained by controlling the reaction conditions.

  13. Efficient tunable luminescence of SiGe alloy sheet polymers

    International Nuclear Information System (INIS)

    Vogg, G.; Meyer, A. J.-P.; Miesner, C.; Brandt, M. S.; Stutzmann, M.

    2001-01-01

    Crystalline SiGe alloy sheet polymers were topotactically prepared from epitaxially grown calcium germanosilicide Ca(Si 1-x Ge x ) 2 precursor films in the whole composition range. These polygermanosilynes are found to be a well-defined mixture of the known siloxene and polygermyne sheet polymers with the OH groups exclusively bonded to silicon. The optical properties determined by photoluminescence and optical reflection measurements identify the mixed SiGe sheet polymers as direct semiconductors with efficient luminescence tunable in the energy range between 2.4 and 1.3 eV. [copyright] 2001 American Institute of Physics

  14. Supramolecular luminescence from oligofluorenol-based supramolecular polymer semiconductors.

    Science.gov (United States)

    Zhang, Guang-Wei; Wang, Long; Xie, Ling-Hai; Lin, Jin-Yi; Huang, Wei

    2013-11-13

    Supramolecular luminescence stems from non-covalent exciton behaviors of active π-segments in supramolecular entities or aggregates via intermolecular forces. Herein, a π-conjugated oligofluorenol, containing self-complementary double hydrogen bonds, was synthesized using Suzuki coupling as a supramolecular semiconductor. Terfluorenol-based random supramolecular polymers were confirmed via concentration-dependent nuclear magnetic resonance (NMR) and dynamic light scattering (DLS). The photoluminescent spectra of the TFOH-1 solution exhibit a green emission band (g-band) at approximately ~520 nm with reversible features, as confirmed through titration experiments. Supramolecular luminescence of TFOH-1 thin films serves as robust evidence for the aggregates of g-band. Our results suggest that the presence of polyfluorene ketone defects is a sufficient condition, rather than a sufficient-necessary condition for the g-band. Supramolecular electroluminescence will push organic devices into the fields of supramolecular optoelectronics, spintronics, and mechatronics.

  15. Supramolecular Luminescence from Oligofluorenol-Based Supramolecular Polymer Semiconductors

    Directory of Open Access Journals (Sweden)

    Guang-Wei Zhang

    2013-11-01

    Full Text Available Supramolecular luminescence stems from non-covalent exciton behaviors of active π-segments in supramolecular entities or aggregates via intermolecular forces. Herein, a π-conjugated oligofluorenol, containing self-complementary double hydrogen bonds, was synthesized using Suzuki coupling as a supramolecular semiconductor. Terfluorenol-based random supramolecular polymers were confirmed via concentration-dependent nuclear magnetic resonance (NMR and dynamic light scattering (DLS. The photoluminescent spectra of the TFOH-1 solution exhibit a green emission band (g-band at approximately ~520 nm with reversible features, as confirmed through titration experiments. Supramolecular luminescence of TFOH-1 thin films serves as robust evidence for the aggregates of g-band. Our results suggest that the presence of polyfluorene ketone defects is a sufficient condition, rather than a sufficient-necessary condition for the g-band. Supramolecular electroluminescence will push organic devices into the fields of supramolecular optoelectronics, spintronics, and mechatronics.

  16. Optimization of Temperature Sensing with Polymer-Embedded Luminescent Ru(II Complexes

    Directory of Open Access Journals (Sweden)

    Nelia Bustamante

    2018-02-01

    Full Text Available Temperature is a key parameter in many fields and luminescence-based temperature sensing is a solution for those applications in which traditional (mechanical, electrical, or IR-based thermometers struggle. Amongst the indicator dyes for luminescence thermometry, Ru(II polyazaheteroaromatic complexes are an appealing option to profit from the widespread commercial technologies for oxygen optosensing based on them. Six ruthenium dyes have been studied, engineering their structure for both photostability and highest temperature sensitivity of their luminescence. The most apt Ru(II complex turned out to be bis(1,10-phenanthroline(4-chloro-1,10-phenanthrolineruthenium(II, due to the combination of two strong-field chelating ligands (phen and a substituent with electron withdrawing effect on a conjugated position of the third ligand (4-Clphen. In order to produce functional sensors, the dye has been best embedded into poly(ethyl cyanoacrylate, due to its low permeability to O2, high temperature sensitivity of the indicator dye incorporated into this polymer, ease of fabrication, and excellent optical quality. Thermosensitive elements have been fabricated thereof as optical fiber tips for macroscopic applications (water courses monitoring and thin spots for microscopic uses (temperature measurements in cell culture-on-a-chip. With such dye/polymer combination, temperature sensing based on luminescence lifetime measurements allows 0.05 °C resolution with linear response in the range of interest (0–40 °C.

  17. Luminescent sensing of organophosphates using europium(III) containing imprinted polymers prepared by RAFT polymerization

    International Nuclear Information System (INIS)

    Southard, Glen E.; Van Houten, Kelly A.; Ott, Edward W.; Murray, George M.

    2007-01-01

    Molecularly imprinted polymers capable of sensing organophosphorous compounds by luminescence have been prepared by reversible addition fragmentation chain transfer (RAFT) polymerization. The polymer contained a dithiobenzoate substituted tris(β-diketonate) europium(III) complex which served as a polymerization substrate and as a luminescent binding site for pinacolyl methylphosphonate (PMP), the hydrolysis product of the nerve agent Soman. The resultant polymer allowed quantitation of PMP in the low ppb range with minimal interference from similar compounds. Polymers were characterized by luminescence spectroscopy and scanning electron microscopy

  18. Spectral-luminescent investigation of polymers doped with europium trisphenoyltrifluoroacetonate compound with 1,10-phenanthroline

    International Nuclear Information System (INIS)

    Karasev, V.E.; Mirochnik, A.G.; Shchelokov, R.N.

    1983-01-01

    Spectral-luminescent characteristics of europium tristhenoyltrifluoroacetonate with 1.10-phenanthpoline in polystyrepe and polyvinyl chloride are investigated. E 4 (TTA) 3 phen during introduction into polymers preserves its composition and structure. Weak temperature dependence of half-Width of luminescent lines qualitatively different from the case of crystal chelate is characteristic for polymers doped with E 4 (TTA) 3 xphen. Investigation into temperature dependence of E 4 3+ luminescent intensity in chelate doped polymers proves the conclusion on weakening processes of excitation energy relaxation by vibration constituents of close and far environment during chelate introduction into polymers

  19. Luminescent lanthanide coordination polymers synthesized via in-situ hydrolysis of dimethyl-3,4-furandicarboxylate

    International Nuclear Information System (INIS)

    Greig, Natalie E.; Einkauf, Jeffrey D.; Clark, Jessica M.; Corcoran, Eric J.; Karram, Joseph P.; Kent, Charles A.; Eugene, Vadine E.; Chan, Benny C.; Lill, Daniel T. de

    2015-01-01

    Dimethyl-3,4-furandicarboxylate undergoes hydrolysis under hydrothermal conditions with lanthanide (Ln) ions to form two-dimensional coordination polymers, [Ln(C 6 H 2 O 5 )(C 6 H 3 O 5 )(H 2 O)] n (Ln=Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu). The resulting materials exhibit luminescent properties with quantum yields and lifetimes for the Eu(III) and Tb(III) compounds of 1.1±0.3% and 0.387±0.0001 ms, and 3.3±0.8% and 0.769±0.006 ms, respectively. Energy values for the singlet and triplet states were determined for dimethyl-3,4-furandicarboxylate and 3,4-furandicarboxylic acid. Excited state dynamics and structural features are examined to explicate the reported quantum yields. A series of other FDC structures is briefly presented. - Graphical abstract: A new two-dimensional coordination polymer derived from the in-situ hydrolysis of a furan dimethyl ester with lanthanide(III) ions was obtained in order to study its photophysical behavior when constructed from trivalent Eu and Tb. Quantum yields, lifetime measurements, and singlet/triplet state energies values were obtained. The nature of the material's excited state dynamics is examined and correlated to its structure in order to explain the overall luminescent efficiency of the system. - Highlights: • A new lanthanide–furandicarboxylate coordination polymer is presented. • Eu and Tb compounds display luminescent properties, albeit with low quantum yields. • Photophysical behavior explained through the compound's triplet state and structure. • Nonradiative deactivation of luminescence through high-energy oscillators was noted. • Molecular modeling of the organic moiety was conducted

  20. Luminescent lanthanide coordination polymers synthesized via in-situ hydrolysis of dimethyl-3,4-furandicarboxylate

    Energy Technology Data Exchange (ETDEWEB)

    Greig, Natalie E.; Einkauf, Jeffrey D.; Clark, Jessica M.; Corcoran, Eric J.; Karram, Joseph P.; Kent, Charles A.; Eugene, Vadine E. [Department of Chemistry & Biochemistry, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431 (United States); Chan, Benny C. [Department of Chemistry, The College of New Jersey, 2000 Pennington Road, Ewing, NJ 08628 (United States); Lill, Daniel T. de, E-mail: ddelill@fau.edu [Department of Chemistry & Biochemistry, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431 (United States)

    2015-05-15

    Dimethyl-3,4-furandicarboxylate undergoes hydrolysis under hydrothermal conditions with lanthanide (Ln) ions to form two-dimensional coordination polymers, [Ln(C{sub 6}H{sub 2}O{sub 5})(C{sub 6}H{sub 3}O{sub 5})(H{sub 2}O)]{sub n} (Ln=Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu). The resulting materials exhibit luminescent properties with quantum yields and lifetimes for the Eu(III) and Tb(III) compounds of 1.1±0.3% and 0.387±0.0001 ms, and 3.3±0.8% and 0.769±0.006 ms, respectively. Energy values for the singlet and triplet states were determined for dimethyl-3,4-furandicarboxylate and 3,4-furandicarboxylic acid. Excited state dynamics and structural features are examined to explicate the reported quantum yields. A series of other FDC structures is briefly presented. - Graphical abstract: A new two-dimensional coordination polymer derived from the in-situ hydrolysis of a furan dimethyl ester with lanthanide(III) ions was obtained in order to study its photophysical behavior when constructed from trivalent Eu and Tb. Quantum yields, lifetime measurements, and singlet/triplet state energies values were obtained. The nature of the material's excited state dynamics is examined and correlated to its structure in order to explain the overall luminescent efficiency of the system. - Highlights: • A new lanthanide–furandicarboxylate coordination polymer is presented. • Eu and Tb compounds display luminescent properties, albeit with low quantum yields. • Photophysical behavior explained through the compound's triplet state and structure. • Nonradiative deactivation of luminescence through high-energy oscillators was noted. • Molecular modeling of the organic moiety was conducted.

  1. The Synthesis and Luminescence-spectroscopic Properties of Fluorescent Condensation Polymers

    Science.gov (United States)

    Barashkov, Nikolai N.

    1985-07-01

    The results of studies on the synthesis of polycondensation phosphorus-containing aliphatic and aromatic polymers as well as the products of polymer-analogue transformations with phosphorus-groups in the side chain are examined. The light absorption and luminescent properties of the polymers obtained and of model compounds having an analogous structure are discussed. The bibliography includes 108 references.

  2. Fabrication of Superhydrophobic and Luminescent Rare Earth/Polymer complex Films.

    Science.gov (United States)

    Wang, Zefeng; Ye, Weiwei; Luo, Xinran; Wang, Zhonggang

    2016-04-18

    The motivation of this work is to create luminescent rare earth/polymer films with outstanding water-resistance and superhydrophobicity. Specifically, the emulsion polymerization of styrene leads to core particles. Then core-shell-structured polymer nanoparticles are synthesized by copolymerization of styrene and acrylic acid on the core surface. The coordination reaction between carboxylic groups and rare earth ions (Eu(3+) and Tb(3+)) generates uniform spherical rare earth/polymer nanoparticles, which are subsequently complexed with PTFE microparticles to obtain micro-/nano-scaled PTFE/rare earth films with hierarchical rough morphology. The films exhibit large water contact angle up to 161° and sliding angle of about 6°, and can emit strong red and green fluorescence under UV excitation. More surprisingly, it is found that the films maintain high fluorescence intensity after submersed in water and even in aqueous salt solution for two days because of the excellent water repellent ability of surfaces.

  3. Single-Molecule Luminescence and High Efficiency Photovoltaic Cells Based on Percolated Conducting Carbon Nanotubes Scaffolds Templated with Light-Harvesting Conjugated Polymers and Nanohybrids

    National Research Council Canada - National Science Library

    Yang, Arnold C

    2009-01-01

    .... Nanocomposites constructed by surface-grafted multiwall carbon nanotubes (CNTs) with conjugated polymers dispersed in a polymer matrix were synthesized to form novel optoelectronic materials that exploit single-molecule effects...

  4. Temperature dependence of the luminescence lifetime of a europium complex immobilized in different polymer matrices

    Energy Technology Data Exchange (ETDEWEB)

    Basu, Bharathi Bai J. [Surface Engineering Division, National Aerospace Laboratories, Bangalore 560017 (India)], E-mail: bharathi@css.nal.res.in; Vasantharajan, N. [Surface Engineering Division, National Aerospace Laboratories, Bangalore 560017 (India)

    2008-10-15

    The temperature dependence of the luminescence lifetime of temperature sensor films based on europium (III) thenoyltrifluoroacetonate (EuTTA) as sensor dye in various polymer matrices such as polystyrene (PS), polymethylmethacrylate (PMMA), polyurethane (PU) and model airplane dope was studied and compared. The luminescence lifetime of EuTTA was found to depend on the polymer matrix. The temperature sensitivity of lifetime was maximum for EuTTA-PS coating in the temperature range of 10-60 deg. C. The effect of concentration of the sensor dye in the polymer on the lifetime and temperature sensitivity was also studied.

  5. Luminescent properties of Europium(III) nitrate with 1,10-phenantroline and cinnamic acid in light - Transforming polymer materials

    Science.gov (United States)

    Kalinovskaya, I. V.; Zadorozhnaya, A. N.

    2018-04-01

    Influence of cinnamic acid on the luminescent properties of the europium(III) nitrate with 1,10-phenantroline in a polymer materials was studied. It was shown that combined use of these rare earth complexes leads to intense luminescence in the 400-700 nm region. Samples containing polymer europium nitrate with 1,10-phenantroline and cinnamic acid at a molar ratio of 1:2,0 had the maximum luminescence intensity and photostability.

  6. Synthesis of high luminescent carbon nanoparticles

    Science.gov (United States)

    Gvozdyuk, Alina A.; Petrova, Polina S.; Goryacheva, Irina Y.; Sukhorukov, Gleb B.

    2017-03-01

    In this article we report an effective and simple method for synthesis of high luminescent carbon nanodots (CDs). In our work as a carbon source sodium dextran sulfate (DS) was used because it is harmless, its analogs are used in medicine as antithrombotic compounds and blood substitutes after hemorrhage. was used as a substrate We investigated the influence of temperature parameters of hydrothermal synthesis on the photoluminescence (PL) intensity and position of emission maxima. We discovered that the PL intensity can be tuned by changing of synthesis temperature and CD concentration.

  7. Absorption and Luminescence of Pyridine-Based Polymers

    National Research Council Canada - National Science Library

    Jessen, S

    1997-01-01

    .... The primary photoexcitations within these polymers are singlet excitons which may emit from individual chains following a random walk to lower energy segments, depending upon the excitation energy...

  8. Quantum dot-polymer conjugates for stable luminescent displays.

    Science.gov (United States)

    Ghimire, Sushant; Sivadas, Anjaly; Yuyama, Ken-Ichi; Takano, Yuta; Francis, Raju; Biju, Vasudevanpillai

    2018-05-23

    The broad absorption of light in the UV-Vis-NIR region and the size-based tunable photoluminescence color of semiconductor quantum dots make these tiny crystals one of the most attractive antennae in solar cells and phosphors in electrooptical devices. One of the primary requirements for such real-world applications of quantum dots is their stable and uniform distribution in optically transparent matrices. In this work, we prepare transparent thin films of polymer-quantum dot conjugates, where CdSe/ZnS quantum dots are uniformly distributed at high densities in a chitosan-polystyrene copolymer (CS-g-PS) matrix. Here, quantum dots in an aqueous solution are conjugated to the copolymer by a phase transfer reaction. With the stable conjugation of quantum dots to the copolymer, we prevent undesired phase separation between the two and aggregation of quantum dots. Furthermore, the conjugate allows us to prepare transparent thin films in which quantum dots are uniformly distributed at high densities. The CS-g-PS copolymer helps us in not only preserving the photoluminescence properties of quantum dots in the film but also rendering excellent photostability to quantum dots at the ensemble and single particle levels, making the conjugate a promising material for photoluminescence-based devices.

  9. Polymer-Particle Pressure-Sensitive Paint with High Photostability

    Directory of Open Access Journals (Sweden)

    Yu Matsuda

    2016-04-01

    Full Text Available We propose a novel fast-responding and paintable pressure-sensitive paint (PSP based on polymer particles, i.e. polymer-particle (pp-PSP. As a fast-responding PSP, polymer-ceramic (PC-PSP is widely studied. Since PC-PSP generally consists of titanium (IV oxide (TiO2 particles, a large reduction in the luminescent intensity will occur due to the photocatalytic action of TiO2. We propose the usage of polymer particles instead of TiO2 particles to prevent the reduction in the luminescent intensity. Here, we fabricate pp-PSP based on the polystyrene particle with a diameter of 1 μm, and investigate the pressure- and temperature-sensitives, the response time, and the photostability. The performances of pp-PSP are compared with those of PC-PSP, indicating the high photostability with the other characteristics comparable to PC-PSP.

  10. Raman scattering and luminescence of high-Tc superconducting oxides

    International Nuclear Information System (INIS)

    Eremenko, V.V.; Gnezdilov, V.P.; Fomin, V.I.; Fugol', I.Ya.; Samovarov, V.N.

    1989-01-01

    Raman and luminescence spectra of high-T c superconducting oxides are summarized, mainly YBa 2 Cu 3 O 7-σ and partly La 2-x Ba x CuO 4-σ . In raman spectra we succeeded to distinguish electron scattering to define the energy gap Δ in the superconducting state. The luminescence spectra are due to the emission of oxygen and interaction with conduction electrons. 70 refs.; 13 figs

  11. Incorporation of Znq2 complexes into mesoporous silica and their transparent polymer luminescent nanocomposites

    International Nuclear Information System (INIS)

    Du Yaying; Fu Yuqin; Shi Yongli; Lue Xiaodan; Lue Changli; Su Zhongmin

    2009-01-01

    Znq 2 -functionalized colloidal mesoporous silicas (Znq 2 -CMS)/polymer transparent nanocomposites were prepared by in situ bulk polymerization. CMS nanoparticles or nanorods with hydroxyl-, mercapto- and sulfonic-functionalized interiors were obtained by different synthetic routes in the nanosize dimensions between 50 and 500 nm. The luminescent Znq 2 complex was successfully introduced in the pores of different mesoporous silicas by chemical adsorption as the driving force. The different internal circumstances of mesoporous silicas had an obvious effect on the luminescence and lifetime of Znq 2 complex. The transparent fluorescent nanocomposites were fabricated from different Znq 2 -CMS and suitable monomers. The Znq 2 -CMS were uniformly dispersed in the polymer matrix without evident aggregation. The photoluminescence properties of Znq 2 -CMS in the transparent matrix exhibited a dependence on the inner surrounding of CMS due to the interaction between Znq 2 -CMS and polymers. The maximum emission peak of the nanocomposites had a red-shift of 28 nm as compared to pure Znq 2 -CMS. - Graphical abstract: Znq 2 -functionalized colloidal mesoporous silicas (Znq 2 -CMS)/polymer transparent fluorescent nanocomposites were prepared by in situ bulk polymerization. The figure shows the synthetic scheme for the Znq 2 -CMS and their transparent bulk nanocomposites.

  12. A General Model of Sensitized Luminescence in Lanthanide-Based Coordination Polymers and Metal-Organic Framework Materials.

    Science.gov (United States)

    Einkauf, Jeffrey D; Clark, Jessica M; Paulive, Alec; Tanner, Garrett P; de Lill, Daniel T

    2017-05-15

    Luminescent lanthanides containing coordination polymers and metal-organic frameworks hold great potential in many applications due to their distinctive spectroscopic properties. While the ability to design coordination polymers for specific functions is often mentioned as a major benefit bestowed on these compounds, the lack of a meaningful understanding of the luminescence in lanthanide coordination polymers remains a significant challenge toward functional design. Currently, the study of these compounds is based on the antenna effect as derived from molecular systems, where organic antennae are used to facilitate lanthanide-centered luminescence. This molecular-based approach does not take into account the unique features of extended network solids, particularly the formation of band structure. While guidelines for the antenna effect are well established, they require modification before being applied to coordination polymers. A series of nine coordination polymers with varying topologies and organic linkers were studied to investigate the accuracy of the antenna effect in coordination polymer systems. By comparing a molecular-based approach to a band-based one, it was determined that the band structure that occurs in aggregated organic solids needs to be considered when evaluating the luminescence of lanthanide coordination polymers.

  13. Perturbing Tandem Energy Transfer in Luminescent Heterobinuclear Lanthanide Coordination Polymer Nanoparticles Enables Real-Time Monitoring of Release of the Anthrax Biomarker from Bacterial Spores.

    Science.gov (United States)

    Gao, Nan; Zhang, Yunfang; Huang, Pengcheng; Xiang, Zhehao; Wu, Fang-Ying; Mao, Lanqun

    2018-06-05

    Lanthanide-based luminescent sensors have been widely used for the detection of the anthrax biomarker dipicolinic acid (DPA). However, mainly based on DPA sensitization to the lanthanide core, most of them failed to realize robust detection of DPA in bacterial spores. We proposed a new strategy for reliable detection of DPA by perturbing a tandem energy transfer in heterobinuclear lanthanide coordination polymer nanoparticles simply constructed by two kinds of lanthanide ions, Tb 3+ and Eu 3+ , and guanosine 5'-monophosphate. This smart luminescent probe was demonstrated to exhibit highly sensitive and selective visual luminescence color change upon exposure to DPA, enabling accurate detection of DPA in complex biosystems such as bacterial spores. DPA release from bacterial spores on physiological germination was also successfully monitored in real time by confocal imaging. This probe is thus expected to be a powerful tool for efficient detection of bacterial spores in responding to anthrax threats.

  14. Luminescent nanocomposites of conducting polymers and in-situ grown CdS quantum dots

    International Nuclear Information System (INIS)

    Borriello, C.; Masala, S.; Nenna, G.; Minarini, C.; Di Luccio, T.; Bizzarro, V.; Re, M.; Pesce, E.

    2010-01-01

    Luminescent PVK:CdS and P3HT:CdS nanocomposites with enhanced electrooptical properties have been synthesized. The nucleation and growth of CdS nanoparticles have been obtained by the thermolysis of a single Cd and S precursor dispersed in the polymers. The size distribution and morphology of the nanoparticles have been studied by TEM analyses. Monodispersive and very small nanoparticles of diameter below 3 nm in PVK and 2 nm in P3HT, have been obtained. The application of such nanocomposites as emitting layers in OLED devices is discussed.

  15. Dependency of non-homogeneity energy dispersion on absorbance line-shape of luminescent polymers

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Marcelo Castanheira da, E-mail: mar_castanheira@yahoo.com.br [Centro de Ciências Biológicas e da Natureza, Universidade Federal do Acre, CP 500, 69915-900 Rio Branco, AC (Brazil); Instituto de Física, Universidade Federal de Uberlândia, CP 593, 38400-902 Uberlândia, MG (Brazil); Santos Silva, H.; Silva, R.A.; Marletta, Alexandre [Instituto de Física, Universidade Federal de Uberlândia, CP 593, 38400-902 Uberlândia, MG (Brazil)

    2013-01-16

    In this paper, we study the importance of the non-homogeneity energy dispersion on absorption line-shape of luminescent polymers. The optical transition probability was calculated based on the molecular exciton model, Franck–Condon states, Gaussian distribution of non-entangled chains with conjugate degree n, semi-empirical parameterization of energy gap, electric dipole moment, and electron-vibrational mode coupling. Based on the approach of the energy gap functional dependence 1/n, the inclusion of the non-homogeneity energy dispersion 1/n{sup 2} is essential to obtain good experimental data agreement, mainly, where the absorption spectra display peaks width of about 65 meV. For unresolved absorption spectra, such as those observed for a large number of conjugated polymers processed via spin-coating technique, for example, the non-homogeneity energy dispersion parameterization is not significant. Results were supported by the application of the model for poly (p-phenylene vinylene) films.

  16. Anti-Stokes Luminescence in High Quality Quantum Wells

    Science.gov (United States)

    Vinattieri, A.; Bogani, F.; Miotto, A.; Ceccherini, S.

    1997-11-01

    We present a detailed investigation of the anti-Stokes (AS) luminescence which originates from exciton recombination when below gap excitation is used, in a set of high quality quantum well structures. We observe strong excitonic resonances in the AS signal as measured from photoluminescence and photoluminescence excitation spectra. We demonstrate that neither the electromagnetic coupling between the wells nor the morphological disorder can explain this up-conversion effect. Time-resolved luminescence data after ps excitation and fs correlation spectroscopy results provide clear evidence of the occurrence of a two-step absorption which is assisted by the exciton population resonantly excited by the first photon.

  17. Synthesis, Crystal Structure, and Luminescence Properties of a New Calcium(II Coordination Polymer Based on L-Malic Acid

    Directory of Open Access Journals (Sweden)

    Duraisamy Senthil Raja

    2013-01-01

    Full Text Available A new calcium coordination polymer [Ca(HL-MA]n (H3L-MA = L-malic acid has been solvothermally synthesized. The structure of the newly synthesized complex has been determined by single-crystal X-ray diffraction analysis and further characterized by elemental analysis, reflectance UV-Vis & IR spectra, powder X-ray diffraction (PXRD, and thermogravimetric analysis (TGA. The single crystal structure analysis showed that the complex forms three-dimensional framework. The new Ca(II complex has displayed very high thermal stability which was inferred from TGA and PXRD results. As far as the optical property of the new complex is concerned, the complex emitted its own characteristic sensitized luminescence.

  18. HIGH TEMPERATURE POLYMER FUEL CELLS

    DEFF Research Database (Denmark)

    Jensen, Jens Oluf; Qingfeng, Li; He, Ronghuan

    2003-01-01

    This paper will report recent results from our group on polymer fuel cells (PEMFC) based on the temperature resistant polymer polybenzimidazole (PBI), which allow working temperatures up to 200°C. The membrane has a water drag number near zero and need no water management at all. The high working...

  19. Luminescent Lanthanide Reporters for High-Sensitivity Novel Bioassays

    Energy Technology Data Exchange (ETDEWEB)

    Anstey, Mitchell R. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Fruetel, Julia A. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Foster, Michael E. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Hayden, Carl C. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Buckley, Heather L. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Arnold, John [Sandia National Lab. (SNL-CA), Livermore, CA (United States)

    2013-09-01

    Biological imaging and assay technologies rely on fluorescent organic dyes as reporters for a number of interesting targets and processes. However, limitations of organic dyes such as small Stokes shifts, spectral overlap of emission signals with native biological fluorescence background, and photobleaching have all inhibited the development of highly sensitive assays. To overcome the limitations of organic dyes for bioassays, we propose to develop lanthanide-based luminescent dyes and demonstrate them for molecular reporting applications. This relatively new family of dyes was selected for their attractive spectral and chemical properties. Luminescence is imparted by the lanthanide atom and allows for relatively simple chemical structures that can be tailored to the application. The photophysical properties offer unique features such as narrow and non-overlapping emission bands, long luminescent lifetimes, and long wavelength emission, which enable significant sensitivity improvements over organic dyes through spectral and temporal gating of the luminescent signal.Growth in this field has been hindered due to the necessary advanced synthetic chemistry techniques and access to experts in biological assay development. Our strategy for the development of a new lanthanide-based fluorescent reporter system is based on chelation of the lanthanide metal center using absorbing chromophores. Our first strategy involves "Click" chemistry to develop 3-fold symmetric chelators and the other involves use of a new class of tetrapyrrole ligands called corroles. This two-pronged approach is geared towards the optimization of chromophores to enhance light output.

  20. Syntheses, structures and luminescent properties of lanthanide coordination polymers assembled from imidazophenanthroline derivative and oxalate ligands

    International Nuclear Information System (INIS)

    Zhao, Hui; Sun, Xiao-Xia; Hu, Huai-Ming; An, Ran; Yang, Meng-Lin; Xue, Ganglin

    2017-01-01

    Nine new lanthanide coordination polymers, namely, [Ln(Hsfpip)(ox) 0.5 (H 2 O)] n ·2n(H 2 O) ((Ln=Eu (1), Tb (2), Dy (3), Ho (4), Er (5), Yb (6), Y(7)), [Ln(H 2 sfpip)(ox)(H 2 O) 4 ] n ·2n(H 2 O) (Ln=Nd (8) Sm (9)), [H 2 ox=oxalic acid, H 3 sfpip=2-(2,4-disulfophenyl)imidazo(4,5-f)(1,10)-phenanthroline] have been synthesized under hydrothermal conditions and characterized by IR spectra, elemental analysis, powder X-ray diffraction and single crystal X-ray diffraction. When sodium oxalate is added, the reactions of lanthanide ions with H 3 sfpip resulted in two types of structures. Compounds 1–7 are obtained at pH 5.0 and exhibit 3D tfz-d networks with ox 2− anions as linkers to bridge the adjacent layers. Compounds 8–9 are obtained at pH 2.0, and display a 1D chain which is further extended to a 3D supramolecular framework through intermolecular hydrogen bonds and π-π interactions. The structural variation from compounds 1–7 to 8–9 can attribute to the pH effect on construction of lanthanide coordination polymers. Moreover, the thermal stabilities and luminescence properties of 1–9 were also investigated. - Graphical abstract: Nine new lanthanide coordination polymers have been synthesized under hydrothermal conditions. Compounds 1–7 exhibit a 3D tfz-d network. Compounds 8–9 display a 1D chain structure. The structural variation from compounds 1–7 to 8–9 can attribute to the pH effect on construction of lanthanide coordination polymers. - Highlights: • Nine lanthanide coordination polymers were prepared under hydrothermal conditions. • Their crystal structures have been determined. • The luminescence and thermal stabilities were studied in the solid state.

  1. Syntheses, structures and luminescent properties of lanthanide coordination polymers assembled from imidazophenanthroline derivative and oxalate ligands

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Hui; Sun, Xiao-Xia; Hu, Huai-Ming, E-mail: ChemHu1@NWU.EDU.CN; An, Ran; Yang, Meng-Lin; Xue, Ganglin

    2017-01-15

    Nine new lanthanide coordination polymers, namely, [Ln(Hsfpip)(ox){sub 0.5}(H{sub 2}O)]{sub n}·2n(H{sub 2}O) ((Ln=Eu (1), Tb (2), Dy (3), Ho (4), Er (5), Yb (6), Y(7)), [Ln(H{sub 2}sfpip)(ox)(H{sub 2}O){sub 4}]{sub n}·2n(H{sub 2}O) (Ln=Nd (8) Sm (9)), [H{sub 2}ox=oxalic acid, H{sub 3}sfpip=2-(2,4-disulfophenyl)imidazo(4,5-f)(1,10)-phenanthroline] have been synthesized under hydrothermal conditions and characterized by IR spectra, elemental analysis, powder X-ray diffraction and single crystal X-ray diffraction. When sodium oxalate is added, the reactions of lanthanide ions with H{sub 3}sfpip resulted in two types of structures. Compounds 1–7 are obtained at pH 5.0 and exhibit 3D tfz-d networks with ox{sup 2−} anions as linkers to bridge the adjacent layers. Compounds 8–9 are obtained at pH 2.0, and display a 1D chain which is further extended to a 3D supramolecular framework through intermolecular hydrogen bonds and π-π interactions. The structural variation from compounds 1–7 to 8–9 can attribute to the pH effect on construction of lanthanide coordination polymers. Moreover, the thermal stabilities and luminescence properties of 1–9 were also investigated. - Graphical abstract: Nine new lanthanide coordination polymers have been synthesized under hydrothermal conditions. Compounds 1–7 exhibit a 3D tfz-d network. Compounds 8–9 display a 1D chain structure. The structural variation from compounds 1–7 to 8–9 can attribute to the pH effect on construction of lanthanide coordination polymers. - Highlights: • Nine lanthanide coordination polymers were prepared under hydrothermal conditions. • Their crystal structures have been determined. • The luminescence and thermal stabilities were studied in the solid state.

  2. Modeling the influence of silver nanoparticles on the f–f luminescence of the EuEDTA complex in the polyvinylpirrolidone polymer

    Energy Technology Data Exchange (ETDEWEB)

    Couto dos Santos, M.A., E-mail: marcoscouto@ufs.br [Departamento de Física, Universidade Federal de Sergipe/CCET, São Cristóvão, SE 49100-000 (Brazil); Malta, O.L. [Departamento de Química Fundamental, Universidade Federalde Pernambuco/CCEN, Cidade Universitária, Recife, PE 50670-901 (Brazil); Reisfeld, R. [The Hebrew University of Jerusalem, Chemistry Institute, E. Safra Campus, 91904 Jerusalem (Israel)

    2016-02-15

    A theoretical analysis on experimental results previously obtained on the influence of silver nanoparticles in a polyvinylpirrolidone (PVP) polymer film containing a trivalent europium complex with EDTA ligand is made. Depending on the excitation source (at 393 nm with a xenon lamp or at 532 nm with a focused diode laser) the characteristic Eu{sup 3+} luminescence is observed to be enhanced by factors between 5 and 50. The theoretical analysis presumes a migration process of the EuEDTA complex units towards the silver nanoparticles, during the synthesis of the composite samples, and subsequently the treatment of the competition between local high field gradient effects and Eu{sup 3+} ion to the silver nanoparticles energy transfer successfully accounts for the observed luminescence enhancement factors. - Highlights: • Unusual luminescence enhancement of EuEDTA–silver nanoparticles–polyvinylpyrrolidone is treated theoretically. • A migration process of the EuEDTA complex units towards the silver nanoparticles is assumed. • The local high field gradient effects successfully accounts for the observed unusual luminescence enhancement factor of 50.

  3. Synthesis, crystal structure and luminescence properties of lanthanide coordination polymers with a new semirigid bridging thenylsalicylamide ligand

    International Nuclear Information System (INIS)

    Song, Xue-Qin; Wang, Li; Zhao, Meng-Meng; Wang, Xiao-Run; Peng, Yun-Qiao; Cheng, Guo-Quan

    2013-01-01

    Two new lanthanide coordination polymers based on a semirigid bridging thenylsalicylamide ligand ([Ln 2 L 3 (NO 3 ) 6 ]·(C 4 H 8 O 2 ) 2 ) ∞ were obtained and characterized by elemental analysis, X-ray diffraction, IR and TGA measurements. The two compounds are isostructure and possess one dimensional trapezoid ladder-like chain built up from the connection of isolated LnO 3 (NO 3 ) 3 polyhedra (distorted monocapped antisquare prism) through the ligand. The photoluminescence analysis suggest that there is an efficient ligand-to-Ln(III) energy transfer in Tb(III) complex and the ligand is an efficient “antenna” for Tb(III). From a more general perspective, the results demonstrated herein provide the possibility of controlling the formation of the desired lanthanide coordination structure to enrich the crystal engineering strategy and enlarge the arsenal for developing excellent luminescent lanthanide coordination polymers. - Graphical abstract: We present herein one dimensional lanthanide coordination polymers of a new semirigid exo-bidentate ligand which not only display interesting structures but also possess strong luminescence properties. Display Omitted - Highlights: • We present lanthanide coordination polymers of a new semirigid exo-bidentate ligand. • The lanthanide coordination polymers exhibit interesting structures. • The luminescent properties of Tb(III) complexes are discussed in detail

  4. Syntheses, structures and luminescent properties of lanthanide coordination polymers assembled from imidazophenanthroline derivative and oxalate ligands

    Science.gov (United States)

    Zhao, Hui; Sun, Xiao-Xia; Hu, Huai-Ming; An, Ran; Yang, Meng-Lin; Xue, Ganglin

    2017-01-01

    Nine new lanthanide coordination polymers, namely, [Ln(Hsfpip)(ox)0.5(H2O)]n·2n(H2O) ((Ln=Eu (1), Tb (2), Dy (3), Ho (4), Er (5), Yb (6), Y(7)), [Ln(H2sfpip)(ox)(H2O)4]n·2n(H2O) (Ln=Nd (8) Sm (9)), [H2ox=oxalic acid, H3sfpip=2-(2,4-disulfophenyl)imidazo(4,5-f)(1,10)-phenanthroline] have been synthesized under hydrothermal conditions and characterized by IR spectra, elemental analysis, powder X-ray diffraction and single crystal X-ray diffraction. When sodium oxalate is added, the reactions of lanthanide ions with H3sfpip resulted in two types of structures. Compounds 1-7 are obtained at pH 5.0 and exhibit 3D tfz-d networks with ox2- anions as linkers to bridge the adjacent layers. Compounds 8-9 are obtained at pH 2.0, and display a 1D chain which is further extended to a 3D supramolecular framework through intermolecular hydrogen bonds and π-π interactions. The structural variation from compounds 1-7 to 8-9 can attribute to the pH effect on construction of lanthanide coordination polymers. Moreover, the thermal stabilities and luminescence properties of 1-9 were also investigated.

  5. A New 1D Chained Coordination Polymer: Synthesis, Crystal Structure, Antitumor Activity and Luminescent Property

    Directory of Open Access Journals (Sweden)

    Xi-Shi Tai

    2015-11-01

    Full Text Available A new 1D chained coordination polymer of Zn(II, {[Zn(L2(4,4′-bipy]·(H2O}n(1 (HL = N-acetyl-l-phenylalanine; 4,4′-bipy = 4,4′-bipyridine has been synthesized and characterized by elemental analysis, IR and X-ray single crystal diffraction analysis. Theresults show that each asymmetric unit of Zn(II complex belongs to monoclinic, space group P21 with a = 11.421(2 Å, b = 9.2213(17 Å, c = 15.188(3 Å,β = 106.112(3°, V = 1536.7(5 Å3, Z = 2, Dc = 1.444 g·cm−3, µ = 0.857 mm−1, F(000 = 696, and final R1 = 0.0439, ωR2 = 0.1013. The molecules form one-dimensional chained structure by its the bridging 4,4′-bipyridine ligands. The antitumor activities and luminescent properties of Zn(II coordination polymer have also been investigated.

  6. Syntheses, structures and luminescence properties of lanthanide coordination polymers with helical character

    International Nuclear Information System (INIS)

    Zhou Ruisha; Cui Xiaobing; Song Jiangfeng; Xu Xiaoyu; Xu Jiqing; Wang Tiegang

    2008-01-01

    A series of lanthanide coordination polymers, (Him) n [Ln(ip) 2 (H 2 O)] n [Ln=La(1), Pr(2), Nd(3) and Dy(4), H 2 ip=isophthalic acid, im=imidazole] and [Y 2 (ip) 3 (H 2 O) 2 ] n .nH 2 O (5), have been synthesized and characterized by elemental analyses, infrared (IR), ultraviolet-visible-near infrared (UV-Vis-NIR) and single-crystal X-ray diffraction analyses. The isostructural compounds 1-4 possess 3-D structures with three different kinds of channels. Compound 5 features a 2-D network making of two different kinds of quadruple-helical chains. Compounds 2 and 3 present the characteristic emissions of Pr(III) and Nd(III) ions in NIR region, respectively. Compound 4 shows sensitized luminescence of Dy(III) ions in visible region. - Graphical abstract: A series of lanthanide coodination polymers, (Him) n [Ln(ip) 2 (H 2 O)] n [Ln=La(1), Pr(2), Nd(3) and Dy(4)] and [Y 2 (ip) 3 (H 2 O) 2 ] n .nH 2 O (5), have been reported. The isostructural compounds 1-4 possess 3-D structures with three different kinds of channels. Compound 5 displays a 2-D network making of two kinds of quadruple-helical chains. Display Omitted

  7. Influence of electric field on the properties of the polymer stabilized luminescent quantum dots in aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Zharkova, Irina S.; Markina, Natalia E. [Saratov State University, Astrakhanskaya 83, 410012 Saratov (Russian Federation); Markin, Alexey V., E-mail: av_markin@mail.ru [Saratov State University, Astrakhanskaya 83, 410012 Saratov (Russian Federation); Drozd, Daniil D.; Speranskaya, Elena S. [Saratov State University, Astrakhanskaya 83, 410012 Saratov (Russian Federation); Goryacheva, Irina Yu. [Saratov State University, Astrakhanskaya 83, 410012 Saratov (Russian Federation); Saint-Petersburg State University, Universitetskii pr. 26, 198504 Petrodvorets, Saint-Petersburg (Russian Federation)

    2016-08-15

    The application of external electric field for verification of quantum dots (QDs) stability in aqueous medium was proposed. Hydrophilic CdSe core-shell nanocrystals were synthesized and used with three polymer-based organic stabilizers, two of which contain PEG chains. An increasing of the stability under applied electric field (EF) was shown for stabilizer containing higher amount of PEG chains and terminal amino-groups: introduction of additional PEG chains allowed reducing degradation of luminescence intensity for about 60%. The changes of QDs solutions after EF treatment were examined by dynamic light scattering measurements, luminescence and absorbance spectroscopy, and conductivity measurements and explained by decreasing of quantum yield of the samples due to degradation of stabilizer coating. - Highlights: • Hydrophilic QDs with three types of stabilizer coatings were prepared and treated by electric field in water environment. • Permanent QDs luminescence quenching in aqueous medium under low electric field strength was observed. • Luminescence stability to EF treatment increases by stabilizer with higher PEG content. • Redox mechanism of luminescence quenching was proved via conductivity, DLS, and UV-visible absorbance measurements.

  8. "Green" High-Temperature Polymers

    Science.gov (United States)

    Meador, Michael A.

    1998-01-01

    PMR-15 is a processable, high-temperature polymer developed at the NASA Lewis Research Center in the 1970's principally for aeropropulsion applications. Use of fiber-reinforced polymer matrix composites in these applications can lead to substantial weight savings, thereby leading to improved fuel economy, increased passenger and payload capacity, and better maneuverability. PMR-15 is used fairly extensively in military and commercial aircraft engines components seeing service temperatures as high as 500 F (260 C), such as the outer bypass duct for the F-404 engine. The current world-wide market for PMR-15 materials (resins, adhesives, and composites) is on the order of $6 to 10 million annually.

  9. Highly Luminescent Dual Mode Polymeric Nanofiber-Based Flexible Mat for White Security Paper and Encrypted Nanotaggant Applications.

    Science.gov (United States)

    Gangwar, Amit Kumar; Gupta, Ashish; Kedawat, Garima; Kumar, Pawan; Singh, Bhanu Pratap; Singh, Nidhi; Srivastava, Avanish K; Dhakate, Sanjay R; Gupta, Bipin Kumar

    2018-05-23

    Increasing counterfeiting of important data, currency, stamp papers, branded products etc., has become a major security threat which could lead to serious damage to the global economy. Consequences of such damage are compelling for researchers to develop new high-end security features to address full-proof solutions. Herein, we report a dual mode flexible highly luminescent white security paper and nanotaggants composed of nanophosphors incorporated in polymer matrix to form a nanofiber-based mat for anti-counterfeiting applications. The dual mode nanofibers are fabricated by electrospinning technique by admixing the composite of NaYF 4 :Eu 3+ @NaYF 4 :Yb 3+ , Er 3+ nanophosphors in the polyvinyl alcohol solution. This flexible polymer mat derived from nanofibers appears white in daylight, while emitting strong red (NaYF 4 :Eu 3+ ) and green (NaYF 4 :Yb 3+ , Er 3+ ) colors at excitation wavelengths of 254 nm and 980 nm, respectively. These luminescent nanofibers can also be encrypted as a new class of nanotaggants to protect confidential documents. These obtained results suggest that highly luminescent dual mode polymeric nanofiber-based flexible white security paper and nanotaggants could offer next-generation high-end unique security features against counterfeiting. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. A novel stable 3D luminescent uranyl complex for highly efficient and sensitive recognition of Ru3+ and biomolecules

    Science.gov (United States)

    Tian, Hong-Hong; Chen, Liang-Ting; Zhang, Rong-Lan; Zhao, Jian-She; Liu, Chi-Yang; Weng, Ng Seik

    2018-02-01

    A novel highly stable 3D luminescent uranyl coordination polymer, namely {[UO2(L)]·DMA}n (1), was assembled with uranyl salt and a glycine-derivative ligand [6-(carboxymethyl-amino)-4-oxo-4,5-dihydro-[1,3,5]triazin-2-ylamino]-acetic acid (H2L) under solvothermal reaction. Besides, It was found that complex 1 possesses excellent luminescent properties, particularly the efficient selectivity and sensitivity in the recognition of Ru3+, biomacromolecule bovine serum albumin (BSA), biological small molecules dopamine (DA), ascorbic acid (AA) and uric acid (UA) in the water solution based on a "turn-off" mechanism. Accordingly, the luminescent explorations also demonstrated that complex 1 could be acted as an efficient luminescent probe with high quenching efficiency and low detection limit for selectively detecting Ru3+ and biomolecules (DA, AA, UA and BSA). It was noted that the framework structure of complex 1 still remains highly stable after quenching, which was verified by powder X-ray diffraction (PXRD).

  11. Highly luminescent Eu{sup 3+}-doped benzenetricarboxylate based materials

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Ivan G.N. [Departamento de Química Fundamental, Instituto de Química da Universidade de São Paulo, Av. Prof. Lineu Prestes 748, São Paulo 05508-900, SP (Brazil); Mustafa, Danilo, E-mail: dmustafa@iq.usp.br [Departamento de Química Fundamental, Instituto de Química da Universidade de São Paulo, Av. Prof. Lineu Prestes 748, São Paulo 05508-900, SP (Brazil); Andreoli, Bruno [Departamento de Química Fundamental, Instituto de Química da Universidade de São Paulo, Av. Prof. Lineu Prestes 748, São Paulo 05508-900, SP (Brazil); Felinto, Maria C.F.C. [Centro de Química do Meio Ambiente, Instituto de Pesquisas Energéticas e Nucleares, Av. Prof. Lineu Prestes 2242, São Paulo 05508-000, SP (Brazil); Malta, Oscar L. [Departamento de Química Fundamental, Universidade Federal de Pernambuco, Av. Prof. Moraes Rego, 1235, Recife 50670-90, PE (Brazil); Brito, Hermi F., E-mail: hefbrito@iq.usp.br [Departamento de Química Fundamental, Instituto de Química da Universidade de São Paulo, Av. Prof. Lineu Prestes 748, São Paulo 05508-900, SP (Brazil)

    2016-02-15

    [RE(TMA)] anhydrous complexes (RE{sup 3+}: Y, Gd and Lu) present high red emission intensity with a quantum efficiency (~45%) for the [Y(TMA):Eu{sup 3+}] complexes, due to the absence of non-radioactive decay pathways mediated by water molecules. The complexes were prepared in mild conditions. All the compounds are crystalline and thermostable up to 460 °C. Phosphorescence data of the complexes with Y, Gd and Lu show that the T{sub 1} state of the TMA{sup 3−} anion has energy higher than the {sup 5}D{sub 0} emitting level of the Eu{sup 3+} ion, indicating that the ligand can act as an intramolecular energy sensitizer. The photoluminescence properties of the doped materials were studied based on the excitation and emission spectra and luminescence decay curves. The experimental intensity parameters (Ω{sub λ}), lifetimes (τ), radiative (A{sub rad}) and non-radiative (A{sub nrad}) decay rates were determined and discussed. - Highlights: • Highly luminescent Europium doped anhydrous complexes. • Efficient monochromatic red light conversion molecular devices (LCMDs). • High emission quantum efficiencies.

  12. High temperature luminescence of ZnSe:Yb crystals

    Directory of Open Access Journals (Sweden)

    Makhniy V. P.

    2016-05-01

    Full Text Available The problem of obtaining of effective edge luminescence with high temperature stability in the zinc selenide crystals is discussed. This task is solved by using as the dopant rare-earth element yttrium, which is introduced into the undoped ZnSe crystal by diffusion method. Doping was carried out in an evacuated to 10 -4 Torr. and a sealed quartz ampoule, in the opposite ends of which is a sample and a mixture of the crushed Yb and Se. It has been found that the diffusion coefficient of yttrium at a temperature of 1400 K is about 5⋅10 -7 cm 2/sec. It is shown that in the luminescence spectra of ZnSe:Yb samples in the temperature range 295-470 K only blue band is observed. Dependencies of parameters of this band from the excitation level are typical for the annihilation of excitons at their inelastic scattering by free carriers. The efficacy of blue radiation at 300 K is about 30% and does not fall more than twice with increasing temperature up to 470 K, indicating its high thermal stability.

  13. The synthesis and luminescence quenching of the water-soluble polymer-supported tris(2,2'-bipyridine)ruthenium(II) analogue

    International Nuclear Information System (INIS)

    Kurimura, Yoshimi; Shinozaki, Norio; Ito, Fumio; Uratani, Yasuyo; Shigehara, Kiyotaka; Tsuchida, Eishun; Kaneko, Masao; Yamada, Akira.

    1982-01-01

    The p-aminostyrene-N-vinylpyrrolidone copolymer-supported tris(2,2'-bipyridine)ruthenium (II) analogue, [Ru(bpy) 2 (pbyCOOH)] 2 + (bpy = 2,2'-bipyridine and pbyCOOH = polymeric bipyridine ligand), has been prepared, and the luminescence behavior of the polymer complex has been investigated in an aqueous solution. The efficiency of the quenching of the excited state of the polymer complex with [Fe(CN) 6 ] 4 - , [Co(phen) 3 ] 2 + , and Cu 2 + is compared with that of [Ru(bpy) 3 ] 2 + . The quenching of the excited state of the polymer complex by Cu 2 + is strongly enhanced by the effect of the polymer chains. In the polymer complex/Cu 2 + system, the quenching by Cu 2 + in the presence of poly(p-styrenesulfonate) is much more effective than in the absence of the polyion. The characteristics of the polymer complex in terms of the luminescence behavior are discussed. (author)

  14. Highly luminescent hybrid materials based on smectites with polyethylene glycol modified with rhodamine fluorophore

    Czech Academy of Sciences Publication Activity Database

    Sas, S.; Danko, M.; Bizovská, V.; Lang, Kamil; Bujdák, J.

    2017-01-01

    Roč. 138, MAR (2017), s. 25-33 ISSN 0169-1317 Institutional support: RVO:61388980 Keywords : Luminescent polymers * Rhodamine B * Molecular aggregation * Fluorescence * Optical materials Subject RIV: CA - Inorganic Chemistry OBOR OECD: Inorganic and nuclear chemistry Impact factor: 3.101, year: 2016

  15. Surface-Modified Quantum Dots Enhanced Luminescence Polymer Nanocomposites Light Emitting Diode

    National Research Council Canada - National Science Library

    Wei, Kung-Hwa

    2006-01-01

    .... Both the photoluminescence and electroluminescence efficiencies of the polymer nanocomposites are dramatically enhanced--sometimes by more than double--relative to the values of the pure polymer...

  16. Preparation and luminescent properties of ZnO:Ga(La)/polymer nanocomposite

    Czech Academy of Sciences Publication Activity Database

    Gbur, T.; Vlk, M.; Čuba, V.; Beitlerová, Alena; Nikl, Martin

    2013-01-01

    Roč. 56, SEP (2013), s. 102-106 ISSN 1350-4487. [International Conference on Luminescent Detectors and Transformers of Ionizing Radiation 2012 /8./, LUMDETR 2012. Halle (Saale), 10.09.2012-14.09.2012] R&D Projects: GA AV ČR KAN300100802 Institutional support: RVO:68378271 Keywords : zinc oxide * doping * nanocomposite * luminescent materials * photopolymerization Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.140, year: 2013

  17. Synthesis and luminescence properties of tris(bipyridine)ruthenium(II)-containing vinyl polymers

    International Nuclear Information System (INIS)

    Furue, Masaoki; Sumi, Katsuhiro; Nozakura, Shun-ichi

    1981-01-01

    The luminescence properties of poly[Ru(bpy) 2 (6-vinyl-bpy)-co-6-vinyl-bpy], (I) were compared with those of Ru(bpy) 3 2+ at 77 - 298 K. A larger depletion of luminescence intensity and lifetime was observed in I in fluid solution. The dynamic quenching processes were suggested to be the dominant factor for the energy dissipation in I. (author)

  18. Synthesis and luminescent properties of new conjugated polymers based on poly(p-phenylene vinylene)

    Science.gov (United States)

    Gurge, Ronald Matthew

    The "push-pull" electronically substituted polymers poly(2 (5) -bromo-5 (2) -n-hexyloxy-1,4-phenylene vinylene), poly(2 (5) -chloro-5 (2) -n-hexyloxy-1,4-phenylene vinylene) and poly(2 (5) -fluoro-5 (2) -n-hexyloxy-1,4-phenylene vinylene) were synthesized by a soluble precursor method and were used to fabricate light emitting diode (LED) devices. Thermal elimination of the polyether precursors gives final conjugated polymers as flexible red films. Precursor polymers can be spin-cast from solutions onto indium/tin oxide (ITO) pretreated quartz plates, then thermally converted to the final red polymers. Light emitting diode fabrication is then completed by the thin film vapor deposition of calcium, followed by aluminum. LED devices of the "push-pull" polymers give light emission in the 620-635 nm range. Two fluorinated polymers, poly(2-fluoro-1,4-phenylene vinylene) and poly(2,5-difluoro-1,4-phenylene vinylene) were investigated for their electroluminescent (EL) properties. LED's using these materials as emissive layers show substantial EL wavelength shifts (560 nm and 600 nm, respectively) relative to emission from unsubstituted poly(1,4-phenylene vinylene) (565 nm). These differences in EL emission can be attributed to the electronic effects of fluorine substitution. Synthetic strategies were developed for copolymeric materials based on poly(1,4-phenylene vinylene). The alternating block copolymer, poly (1,8-octanedioxy-2,6-dimethoxy-1,4-phenylene-1,2-ethenylene-1,4-phenylene-1,2-ethenylene-1,4-phenylene-1,2-ethenylene- 3,5-dimethoxy-1,4-phenylene) was synthesized by a modified Wittig polymerization utilizing trialkyl phosphonium salts. This resulted in a regiospecific trans-olefination reaction when compared to polymeric materials synthesized through the use of common triaryl-phosphonium salts. Harsh post-Wittig isomerization procedures using Isb2 were bypassed as a result of the high trans-cis ratio of the final copolymer. It was fully characterized using the

  19. Approaches for Making High Performance Polymer Materials from Commodity Polymers

    Institute of Scientific and Technical Information of China (English)

    Xu Xi

    2004-01-01

    A brief surrey of ongoing research work done for improving and enhancing the properties of commodity polymers by the author and author's colleagues is given in this paper. A series of high performance polymers and polymer nanomaterials were successfully prepared through irradiation and stress-induced reactions of polymers and hydrogen bonding. The methods proposed are viable, easy in operation, clean and efficient.1. The effect of irradiation source (UV light, electron beam, γ -ray and microwave), irradiation dose, irradiation time and atmosphere etc. on molecular structure of polyolefine during irradiation was studied. The basic rules of dominating oxidation, degradation and cross-linking reactions were mastered. Under the controlled conditions, cross-linking reactions are prevented, some oxygen containing groups are introduced on the molecular chain of polyolefine to facilitate the interface compatibility of their blends. A series of high performance polymer materials: u-HDPE/PA6,u-HDPE/CaCO3, u-iPP/STC, γ-HDPE/STC, γ-LLDPE/ATH, e-HDPE, e-LLDPE and m-HDPEfilled system were prepared (u- ultraviolet light irradiated, γ- γ-ray irradiated, e- electron beam irradiated, m- microwave irradiated)2. The effect of ultrasonic irradiation, jet and pan-milling on structure and changes in properties of polymers were studied. Imposition of critical stress on polymer chain can cause the scission of bonds to form macroradicals. The macroradicals formed in this way may recombine or react with monomer or other radicals to form linear, branched or cross-linked polymers or copolymers. About 20 kinds of block/graft copolymers have been synthesized from polymer-polymer or polymer-monomer through ultrasonic irradiation.Through jet-milling, the molecular weight of PVC is decreased somewhat, the intensity of its crystalline absorption bonds becomes indistinct. The processability, the yield strength, strength at break and elongation at break of PVC get increased quite a lot after

  20. Rethinking Sensitized Luminescence in Lanthanide Coordination Polymers and MOFs: Band Sensitization and Water Enhanced Eu Luminescence in [Ln(C15H9O5)3(H2O)3]n (Ln = Eu, Tb).

    Science.gov (United States)

    Einkauf, Jeffrey D; Kelley, Tanya T; Chan, Benny C; de Lill, Daniel T

    2016-08-15

    A coordination polymer [Ln(C15H9O9)3(H2O)3]n (1-Ln = Eu(III), Tb(III)) assembled from benzophenonedicarboxylate was synthesized and characterized. The organic component is shown to sensitize lanthanide-based emission in both compounds, with quantum yields of 36% (Eu) and 6% (Tb). Luminescence of lanthanide coordination polymers is currently described from a molecular approach. This methodology fails to explain the luminescence of this system. It was found that the band structure of the organic component rather than the molecular triplet state was able to explain the observed luminescence. Deuterated (Ln(C15H9O9)3(D2O)3) and dehydrated (Ln(C15H9O9)3) analogues were also studied. When bound H2O was replaced by D2O, lifetime and emission increased as expected. Upon dehydration, lifetimes increased again, but emission of 1-Eu unexpectedly decreased. This reduction is reasoned through an unprecedented enhancement effect of the compound's luminescence by the OH/OD oscillators in the organic-to-Eu(III) energy transfer process.

  1. High-resolution light microscopy using luminescent nanoparticles.

    Science.gov (United States)

    Ohulchanskyy, Tymish Y; Roy, Indrajit; Yong, Ken-Tye; Pudavar, Haridas E; Prasad, Paras N

    2010-01-01

    This review presents recent progress in the development of the luminescent nanoparticles for confocal and multiphoton microscopy. Four classes of nanomaterials are discussed: (1) silica-based nanoparticles doped with fluorescent molecules, (2) gold nanoparticles, (3) semiconductor nanocrystals (quantum dots/rods), and (4) nanophosphors. Special considerations are given to recently developed imaging nanoprobes, such as (1) organically modified silica (ORMOSIL) nanoparticles doped with two-photon absorbing fluorophores, which exhibit aggregation-enhanced fluorescence (AEF), and (2) nanophosphors (ceramic nanoparticles containing luminescent lanthanoid ions). Advantages and disadvantages of every class of nanomaterials and their specific applications are briefly discussed.

  2. Radiation luminescence of polymers - emission behaviour of aromatic compounds incorporated in synthetic rubbers

    International Nuclear Information System (INIS)

    Kawanishi, Shunichi; Hagiwara, Miyuki

    1986-01-01

    For a deep understanding of a radiation protection mechanism of some aromatic compounds on synthetic polymers, their optical emission behavior under electron irradiation was studied. The fluorescence light was led out of an irradiation room through a wave guide and detected by a photomultiplier so that less noisy spectrum was obtained. Acenaphthene or acenaphthylene was added to the synthetic rubbers such as ethylene propylene diene terpolymer, styrene butadiene rubber and cis-1,4-polybutadiene. The intensities of optical emission induced by electron beams changed from polymer to polymer, while those by ultraviolet lights were independent of the kind of polymers. The dependence of emission intensity on polymers under electron irradiation was estimated to show the fact that the radiation excited energy transfers occur from the polymer matrix to the additives and that an efficiency of the energy transfer is dependent on kinds of polymers. (author)

  3. Nanostructured ZnO/Y2O3:Eu for use as fillers in luminescent polymer electrolyte composites

    International Nuclear Information System (INIS)

    Abdullah, Mikrajuddin; Panatarani, Camellia; Kim, Tae-Oh; Okuyama, Kikuo

    2004-01-01

    Nanostructured ZnO/Eu and ZnO/Y 2 O 3 :Eu composites have been produced by hydrolizing a mixture of zinc acetate, yttrium acetate and europium acetate in ethanol solution, followed by mixing with lithium hydroxide. By analyzing the ICP data, XRD patterns and luminescence emission spectra we concluded that the europium and yttrium compounds appeared as coating layer on the surface of ZnO nanoparticles. Without heating, these layers were in amorphous state and transformed into crystalline state after annealing at temperatures of above 600 deg. C around 30 min. We observed the presence of lithium hydroxide concentration threshold below which no coating layer was formed on the surface of ZnO nanoparticles. The emission intensity of ZnO/Y 2 O 3 :Eu was found to increase with increasing annealing temperature, while the crystalline size of Y 2 O 3 (close to 20 nm) decreased with increasing the annealing temperature. The powder produced might be used as fillers in luminescent polymer electrolyte composites, which can produce two colors, i.e., red (Eu emission) when excited using a wavelength of around 254 nm and green (emitted by ZnO nanoparticles) when excited using a wavelength of around 365 nm

  4. Luminescence decay in condensed argon under high energy excitation

    International Nuclear Information System (INIS)

    Carvalho, M.J.; Klein, G.

    1978-01-01

    α and β particles were used to study the luminescence of condensed argon. The scintillation decay has always two components independently of the phase and the kind of the exciting particles. Decay time constants are given for solid, liquid and also gaseous argon. Changes in the relative intensity values of the two components are discussed in terms of track effects

  5. High cation transport polymer electrolyte

    Science.gov (United States)

    Gerald, II, Rex E.; Rathke, Jerome W [Homer Glen, IL; Klingler, Robert J [Westmont, IL

    2007-06-05

    A solid state ion conducting electrolyte and a battery incorporating same. The electrolyte includes a polymer matrix with an alkali metal salt dissolved therein, the salt having an anion with a long or branched chain having not less than 5 carbon or silicon atoms therein. The polymer is preferably a polyether and the salt anion is preferably an alkyl or silyl moiety of from 5 to about 150 carbon/silicon atoms.

  6. Study of structure modification influence of polymer matrix on the impurity centers luminescence

    International Nuclear Information System (INIS)

    Akylbaev, Zh.S.; Karitskay, S.G.; Nikitina, L.A.; Kobzev, G.I.

    2002-01-01

    Data on study of influence of polymer matrix structure change on impurity centers fluorescence are cited. In the capacity of polymer matrix the polyvinyl butyryl (PVB) serves, and as fluorescence centers the dye molecules the crystal violet (CV) are serving. Computerized simulation of processes of PVB matrixes structuring under the oxygen action from air, produced under annealing of the film at thermal treatment of liquid polymer. Calculation of KV spectral lines wave length under optimization of the dye-polymer system is carried out by the Mm+ molecular mechanics method, and then by semi-empiric method ZINDO1

  7. Correlation of heterojunction luminescence quenching and photocurrent in polymer-blend photovoltaic diodes

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Rabade, Astrid; Morteani, Arne C.; Friend, Richard H. [Cavendish Laboratory, University of Cambridge (United Kingdom)

    2009-10-19

    Charge generation in organic solar cells proceeds via photogeneration of excitons in the bulk that form geminate electron-hole pairs at the heterojunction formed between electron donor and acceptors. It is shown that an externally applied electric field increases the number of free charges formed from the geminate pair, and quenches the luminescence from the relaxed exciplex with one-to-one correspondence. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  8. Synthesis and Characterization of High Energy Polymers.

    Science.gov (United States)

    1981-03-31

    and characterization of new high energy elastomers. IV. References 1. J.C.W. Chien, T. Kohara , C. P. Lillya, T. Sarubbi, B.-H. Su and R. S. Miller, J...Catalyzed Nitromercuration of Diene Polymers, J.C.W. Chien, T. Kohara , C. P. Lillya, T. Sarubbi, B.-H. Su, and R. S. Miller, J. Polm.. Sci. Polym. Chem. Ed

  9. Manufacturing polymer light emitting diode with high luminance efficiency by solution process

    Science.gov (United States)

    Kim, Miyoung; Jo, SongJin; Yang, Ho Chang; Yoon, Dang Mo; Kwon, Jae-Taek; Lee, Seung-Hyun; Choi, Ju Hwan; Lee, Bum-Joo; Shin, Jin-Koog

    2012-06-01

    While investigating polymer light emitting diodes (polymer-LEDs) fabricated by solution process, surface roughness influences electro-optical (E-O) characteristics. We expect that E-O characteristics such as luminance and power efficiency related to surface roughness and layer thickness of emitting layer with poly-9-Vinylcarbazole. In this study, we fabricated polymer organic light emitting diodes by solution process which guarantees easy, eco-friendly and low cost manufacturing for flexible display applications. In order to obtain high luminescence efficiency, E-O characteristics of these devices by varying parameters for printing process have been investigated. Therefore, we optimized process condition for polymer-LEDs by adjusting annealing temperatures of emission, thickness of emission layer showing efficiency (10.8 cd/A) at 10 mA/cm2. We also checked wavelength dependent electroluminescence spectrum in order to find the correlation between the variation of efficiency and the thickness of the layer.

  10. Luminescence as a new detection method for non-relativistic highly ionizing particles in water/ice neutrino telescopes

    Energy Technology Data Exchange (ETDEWEB)

    Pollmann, Anna [Bergische Universitaet Wuppertal (Germany); Collaboration: IceCube-Collaboration

    2016-07-01

    Cosmic ray detectors use air as a radiator for luminescence. In water and ice detectors Cherenkov light is the dominant light producing mechanism when the particle velocity exceeds the Cherenkov threshold, approximately three quarters of the speed of light. Luminescence is produced by highly ionizing particles passing through matter due to the excitation of the surrounding atoms. The observables of luminescence, such as the wavelength spectrum and decay times, are highly dependent on the properties of the medium. Therefore, the results of measurements, in which luminescence was produced by particles passing through water or ice, vary by two orders of magnitude in intensity. It is shown that, even for the most conservative intensity value, luminescence can be used as a detection method for highly ionizing particles with velocities below the Cherenkov threshold. These could be magnetic monopoles or other massive and highly penetrating exotic particles. In the most optimistic case, luminescence contributes even to the light output of standard model particles.

  11. A family of entangled coordination polymers constructed from a flexible V-shaped long bicarboxylic acid and auxiliary N-donor ligands: Luminescent sensing

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jun [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi' an 710127 (China); College of Chemistry and Environmental Engineering, Sichuan University of Science & Engineering, Zigong 643000 (China); Bai, Chao [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi' an 710127 (China); Hu, Huai-Ming, E-mail: ChemHu1@NWU.EDU.CN [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi' an 710127 (China); Yuan, Fei; Xue, Gang-Lin [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi' an 710127 (China)

    2017-05-15

    Eight Zn(II)-based coordination polymers, namely, [Zn{sub 2}L{sub 2}(2,2’-bipy)]{sub n}·nH{sub 2}O (1), [Zn{sub 2}L{sub 2}(phen)]{sub n}·nH{sub 2}O (2), [ZnL(phen)(H{sub 2}O)]{sub n} (3), [Zn{sub 3}L{sub 3}(4,4’-bipy)]{sub n} (4), [Zn{sub 2}L{sub 2}(4,4’-bipy){sub 2}]{sub n} [Zn{sub 2}L{sub 2}(H{sub 2}O){sub 2}]{sub n}·2nH{sub 2}O (5), [Zn{sub 4}L{sub 4}(bpp){sub 2}]{sub n} (6), [ZnL(bbi){sub 0.5}]{sub n} (7), [ZnL(bpz)]{sub n} (8) (H{sub 2}L=4,4’-([1,2-phenylenebis-(methylene)]bis(oxy))dibenzoic acid, 2,2’-bipy =2,2’-bipyridine, phen =1,10-phenanthroline, 4,4’-bpy=4,4’-bipyridine, bpp =1,3-bis(4-pyridyl)propane, bbi=1,4-bis(imidazol-1-yl)butane, bpz=3,3′,5,5′-tetramethyl-4,4′-bipyrazole), have been hydrothermally synthesized and structurally characterized. 1–8 display various coordination motifs with different entangled forms and conformations due to the effect of the assistant N-donor ligands. The photoluminescent properties of compounds 1–8 in solid state were studied. Interestingly, 3 exhibits highly efficient luminescent sensing for Cu{sup 2+} cations and CrO{sub 4}{sup 2-} anions, as well as detection ability for the different organic solvents and nitro explosives. These results indicated that it could be utilized as a multi-responsive luminescent sensor. Furthermore, compound 3 also shows good chemical resistance to both acidity and alkalinity solutions with pH ranging from 2 to 13. Thus, multi-photofunctionality and fluorescent response to pH have been combined in the 3, which is the first example in the Zn-based hybrid materials. - Graphical abstract: Eight new Zn(II)-based coordination polymers constructed from a flexible V-shaped long bicarboxylic acid and different N-donor ligands have been hydrothermally synthesized through fixing the metal salts and the solvent systems. The photoluminescent properties of complexes 1−8 in solid state were studied. Interestingly, 3 exhibits highly efficient luminescent sensing for Cu{sup 2

  12. A family of entangled coordination polymers constructed from a flexible V-shaped long bicarboxylic acid and auxiliary N-donor ligands: Luminescent sensing

    International Nuclear Information System (INIS)

    Wang, Jun; Bai, Chao; Hu, Huai-Ming; Yuan, Fei; Xue, Gang-Lin

    2017-01-01

    Eight Zn(II)-based coordination polymers, namely, [Zn 2 L 2 (2,2’-bipy)] n ·nH 2 O (1), [Zn 2 L 2 (phen)] n ·nH 2 O (2), [ZnL(phen)(H 2 O)] n (3), [Zn 3 L 3 (4,4’-bipy)] n (4), [Zn 2 L 2 (4,4’-bipy) 2 ] n [Zn 2 L 2 (H 2 O) 2 ] n ·2nH 2 O (5), [Zn 4 L 4 (bpp) 2 ] n (6), [ZnL(bbi) 0.5 ] n (7), [ZnL(bpz)] n (8) (H 2 L=4,4’-([1,2-phenylenebis-(methylene)]bis(oxy))dibenzoic acid, 2,2’-bipy =2,2’-bipyridine, phen =1,10-phenanthroline, 4,4’-bpy=4,4’-bipyridine, bpp =1,3-bis(4-pyridyl)propane, bbi=1,4-bis(imidazol-1-yl)butane, bpz=3,3′,5,5′-tetramethyl-4,4′-bipyrazole), have been hydrothermally synthesized and structurally characterized. 1–8 display various coordination motifs with different entangled forms and conformations due to the effect of the assistant N-donor ligands. The photoluminescent properties of compounds 1–8 in solid state were studied. Interestingly, 3 exhibits highly efficient luminescent sensing for Cu 2+ cations and CrO 4 2- anions, as well as detection ability for the different organic solvents and nitro explosives. These results indicated that it could be utilized as a multi-responsive luminescent sensor. Furthermore, compound 3 also shows good chemical resistance to both acidity and alkalinity solutions with pH ranging from 2 to 13. Thus, multi-photofunctionality and fluorescent response to pH have been combined in the 3, which is the first example in the Zn-based hybrid materials. - Graphical abstract: Eight new Zn(II)-based coordination polymers constructed from a flexible V-shaped long bicarboxylic acid and different N-donor ligands have been hydrothermally synthesized through fixing the metal salts and the solvent systems. The photoluminescent properties of complexes 1−8 in solid state were studied. Interestingly, 3 exhibits highly efficient luminescent sensing for Cu 2+ cations and CrO 4 2- anions, as well as detection ability for the different organic solvents and nitro explosives, in which indicates it could be

  13. Lanthanide coordination polymers based on multi-donor ligand containing pyridine and phthalate moieties: Structures, luminescence and magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Xun [College of Chemistry and Chemical Engineering, Luoyang Normal University, Luoyang 471022 (China); Liu, Lang [College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450002 (China); College of Chemistry and Chemical Engineering, Luoyang Normal University, Luoyang 471022 (China); Wang, Li-Ya, E-mail: wlya@lynu.edu.cn [College of Chemistry and Chemical Engineering, Luoyang Normal University, Luoyang 471022 (China); College of Chemistry and Pharmacy Engineering, Nanyang Normal University, Nanyang 473601 (China); Song, Hong-Liang; Qiang Shi, Zhi; Wu, Xu-Hong [College of Chemistry and Chemical Engineering, Luoyang Normal University, Luoyang 471022 (China); Ng, Seik-Weng [Department of Chemistry, University of Malaya, Kuala Lumpur 50603 (Malaysia); Chemistry Department, Faculty of Science, King Abdulaziz University, Jeddah 80203 (Saudi Arabia)

    2013-10-15

    A new family of five lanthanide-organic coordination polymers incorporating multi-functional N-hetrocyclic dicarboxylate ligand, namely, [Ln{sub 2}(Hdpp){sub 2}(dpp){sub 2}]{sub n}Ln=Pr(1), Eu(2), Gd(3), Dy(4), Er(5) (H{sub 2}dpp=1-(3, 4-dicarboxyphenyl) pyridin-4-ol) have been fabricated successfully through solvothermal reaction of 1-(3,4-dicarboxyphenyl)-4-hydroxypyridin-1-ium chloride with trivalent lanthanide salts, and have been characterized systematically. The complexes 1–5 are isomorphous and isostructural. They all feature three dimensional (3D) frameworks based on the interconnection of 1D double chains composed of the binuclear moiety [Ln{sub 2}(Hdpp){sub 2}]{sup 4+} basic carboxylate as secondary building unit (SBU). The results of magnetic analysis shows the same bridging fashion of carboxylic group in this case results in the different magnetic properties occurring within lanthanide polymers. Moreover, the Eu(III) and Dy(III) complexes display characteristic luminescence emission in the visible regions. - Graphical abstract: A new family of lanthanide-organic frameworks incorporating multi-donor twisted ligand has been fabricated successfully, and has been characterized systematically. The complexes 1–5 are isostructural, and all feather three dimensional (3D) frameworks based on the interconnection of 1D double stride chains composed of the binuclear moiety [Ln{sub 2}(Hdpp){sub 2}]{sup 2+} basic carboxylate as secondary building unit (SBU). Display Omitted - Highlights: • New family of lanthanide–organic coordination polymers incorporating multifunctional N-hetrocyclic dicarboxylate ligand has been fabricated. • They have been characterized systematically. • They all feather three dimensional frameworks based on the binuclear moiety of [Ln{sub 2}(Hdpp){sub 2}]{sup 2+}. • The Eu(III) and Dy(III) analogues exhibit intense photoluminescence.

  14. Highly Water-Stable Lanthanide-Oxalate MOFs with Remarkable Proton Conductivity and Tunable Luminescence.

    Science.gov (United States)

    Zhang, Kun; Xie, Xiaoji; Li, Hongyu; Gao, Jiaxin; Nie, Li; Pan, Yue; Xie, Juan; Tian, Dan; Liu, Wenlong; Fan, Quli; Su, Haiquan; Huang, Ling; Huang, Wei

    2017-09-01

    Although proton conductors derived from metal-organic frameworks (MOFs) are highly anticipated for various applications including solid-state electrolytes, H 2 sensors, and ammonia synthesis, they are facing serious challenges such as poor water stability, fastidious working conditions, and low proton conductivity. Herein, we report two lanthanide-oxalate MOFs that are highly water stable, with so far the highest room-temperature proton conductivity (3.42 × 10 -3 S cm -1 ) under 100% relative humidity (RH) among lanthanide-based MOFs and, most importantly, luminescent. Moreover, the simultaneous response of both the proton conductivity and luminescence intensity to RH allows the linkage of proton conductivity with luminescence intensity. This way, the electric signal of proton conductivity variation versus RH will be readily translated to optical signal of luminescence intensity, which can be directly visualized by the naked eye. If proper lanthanide ions or even transition-metal ions are used, the working wavelengths of luminescence emissions can be further extended from visible to near infrared light for even wider-range applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Radioresistance increase in polymers at high pressures

    International Nuclear Information System (INIS)

    Milinchuk, V.; Kirjukhin, V.; Klinshpont, E.

    1977-01-01

    The effect was studied of very high pressures ranging within 100 and 2,700 MPa on the radioresistance of polytetrafluoroethylene, polypropylene and polyethylene in gamma irradiation. For experiments industrial polymers in the shape of blocks, films and fibres were used. It is shown that in easily breakable polymers, such as polytetrafluoroethylene and polypropylene 1.3 to 2 times less free radicals are formed as a result of gamma irradiation and a pressure of 150 MPa than at normal pressure. The considerably reduced radiation-chemical formation of radicals and the destruction suppression by cross-linking in polymers is the evidence of the polymer radioresistance in irradiation at high pressures. (J.B.)

  16. High temperature polymer concrete compositions

    Science.gov (United States)

    Fontana, Jack J.; Reams, Walter

    1985-01-01

    This invention is concerned with a polymer concrete composition, which is a two-component composition useful with many bases including metal. Component A, the aggregate composition, is broadly composed of silica, silica flour, portland cement, and acrylamide, whereas Component B, which is primarily vinyl and acrylyl reactive monomers, is a liquid system. A preferred formulation emphasizing the major necessary components is as follows: ______________________________________ Component A: Silica sand 60-77 wt. % Silica flour 5-10 wt. % Portland cement 15-25 wt. % Acrylamide 1-5 wt. % Component B: Styrene 50-60 wt. % Trimethylolpropane 35-40 wt. % trimethacrylate ______________________________________ and necessary initiators, accelerators, and surfactants.

  17. Water evaporation on highly viscoelastic polymer surfaces.

    Science.gov (United States)

    Pu, Gang; Severtson, Steven J

    2012-07-03

    Results are reported for a study on the evaporation of water droplets from a highly viscoelastic acrylic polymer surface. These are contrasted with those collected for the same measurements carried out on polydimethylsiloxane (PDMS). For PDMS, the evaporation process involves the expected multistep process including constant drop area, constant contact angle, and finally a combination of these steps until the liquid is gone. In contrast, water evaporation from the acrylic polymer shows a constant drop area mode throughout. Furthermore, during the evaporation process, the drop area actually expands on the acrylic polymer. The single mode evaporation process is consistent with formation of wetting structures, which cannot be propagated by the capillary forces. Expansion of the drop area is attributed to the influence of the drop capillary pressure. Furthermore, the rate of drop area expansion is shown to be dependent on the thickness of the polymer film.

  18. Luminescent decay and spectra of impurity-activated alkali halides under high pressure

    International Nuclear Information System (INIS)

    Klick, D.I.

    1977-01-01

    The effect of high pressure on the luminescence of alkali halides doped with the transition-metal ions Cu + and Ag + and the heavy-metal ions In + and Tl + was investigated to 140 kbar. Measurement of spectra allowed the prediction of kinetic properties, and the predictions agree with lifetime data

  19. Highly sensitive luminescence method of scandium determination in the products of metallurgical reprocessing

    International Nuclear Information System (INIS)

    Matveets, M.A.; Akhmetova, S.D.

    1988-01-01

    Highly sensitive reaction of scandium with 1,10-phenanthroline and eosin is used for the development of luminescence method of its determination in metallurgical products. The effect of interfering elements is eliminated by scandium extraction with monocarboxylic acids. The method permits to determine scandium content from 5 x 10 -5 % (Sr 0.15 - 0.25)

  20. Luminescent GdVO_4:Sm"3"+ quantum dots enhance power conversion efficiency of bulk heterojunction polymer solar cells by Förster resonance energy transfer

    International Nuclear Information System (INIS)

    Bishnoi, Swati; Gupta, Vinay; Sharma, Gauri D.; Chand, Suresh; Sharma, Chhavi; Kumar, Mahesh; Haranath, D.; Naqvi, Sheerin

    2016-01-01

    In this work, we report enhanced power conversion efficiency (PCE) of bulk heterojunction polymer solar cells by Förster resonance energy transfer (FRET) from samarium-doped luminescent gadolinium orthovanadate (GdVO_4:Sm"3"+) quantum dots (QDs) to polythieno[3,4-b]-thiophene-co-benzodithiophene (PTB7) polymer. The photoluminescence emission spectrum of GdVO_4:Sm"3"+ QDs overlaps with the absorption spectrum of PTB7, leading to FRET from GdVO_4:Sm"3"+ to PTB7, and significant enhancements in the charge-carrier density of excited and polaronic states of PTB7 are observed. This was confirmed by means of femtosecond transient absorption spectroscopy. The FRET from GdVO_4:Sm"3"+ QDs to PTB7 led to a remarkable increase in the power conversion efficiency (PCE) of PTB7:GdVO_4:Sm"3"+:PC_7_1BM ([6,6]-phenyl-C_7_1-butyric acid methyl ester) polymer solar cells. The PCE in optimized ternary blend PTB7:GdVO_4:Sm"3"+:PC_7_1BM (1:0.1:1.5) is increased to 8.8% from 7.2% in PTB7:PC_7_1BM. This work demonstrates the potential of rare-earth based luminescent QDs in enhancing the PCE of polymer solar cells.

  1. [Synthesis of reserve polyhydroxyalkanoates by luminescent bacteria].

    Science.gov (United States)

    Boiandin, A N; Kalacheva, G S; Rodicheva, E K; Volova, T G

    2008-01-01

    The ability of marine luminescent bacteria to synthesize polyesters of hydroxycarboxylic acids (polyhydroxyalkanoates, PHA) as reserve macromolecules was studied. Twenty strains from the collection of the luminescent bacteria CCIBSO (WDSM839) of the Institute of Biophysics, Siberian Branch, Russian Academy of Sciences, assigned to different taxa (Photobacterium leiognathi, Ph. phosphoreum, Vibrio harveyi, and V. fischeri) were analyzed. The most productive strains were identified, and the conditions ensuring high polymer yields in batch culture (40-70% of the cell dry mass weight) were determined. The capacity of synthesizing two- and three-component polymers containing hydroxybutyric acid as the main monomer and hydroxyvaleric and hydroxyhexanoic acids was revealed in Ph. leiognathi and V. harveyi strains. The results allow luminescent microorganisms to be regarded as new producers of multicomponent polyhydroxyalkanoates.

  2. Preparation of carbon quantum dots based high photostability luminescent membranes.

    Science.gov (United States)

    Zhao, Jinxing; Liu, Cui; Li, Yunchuan; Liang, Jiyuan; Liu, Jiyan; Qian, Tonghui; Ding, Jianjun; Cao, Yuan-Cheng

    2017-06-01

    Urethane acrylate (UA) was used to prepare carbon quantum dots (C-dots) luminescent membranes and the resultants were examined with FT-IR, mechanical strength, scanning electron microscope (SEM) and quantum yields (QYs). FT-IR results showed the polyurethane acrylate (PUA) prepolymer -C = C-vibration at 1101 cm -1 disappeared but there was strong vibration at1687cm -1 which was contributed from the-C = O groups in cross-linking PUA. Mechanical strength results showed that the different quantity of C-dots loadings and UV-curing time affect the strength. SEM observations on the cross-sections of the membranes are uniform and have no structural defects, which prove that the C-dots are compatible with the water-soluble PUA resin. The C-dot loading was increased from 0 to 1 g, the maximum tensile stress was nearly 2.67 MPa, but the tensile strain was decreased from 23.4% to 15.1% and 7.2% respectively. QYs results showed that the C-dots in the membrane were stable after 120 h continuous irradiation. Therefore, the C-dots photoluminescent film is the promising material for the flexible devices in the future applications. Copyright © 2016 John Wiley & Sons, Ltd.

  3. High-temperature peaks of thermostimulated luminescence in the ammonium halogens

    International Nuclear Information System (INIS)

    Kim, L.M.; Musenova, Eh.K.; Mukhamedrakhimov, K.U.

    2003-01-01

    The ammonium halogen crystals (AHC) are the close analogs of the alkali halogen crystals by the type of chemical bonds and crystal lattice structure. The ammonium halogen after irradiation by X-rays within 80-300 K range have two peaks of thermo-stimulation luminescence. Its maximums in dependence of anions type are in the 110-120 K and 170-180 K ranges. The first range is related with activation of auto-localized holes migration, and the second one - with the NH 3 + defects decay. Experimentally is established, that the pure ammonium halogens have memory about the previous irradiation at heating up to 300 K. After repeat irradiation the recombination luminescence high-temperature peak's shoulder is appearing. The second luminescence peak's shoulder revealing does not depend on the impurity center nature. It is known, that in the AHC there is the next thermo-stimulation luminescence peak within 340-360 K. The thermal annealing of this peak leads to the memory effect disappearance. So, the observing phenomenon is related with own defect of the matrix in the cation sublattice. Experimentally is established, that at a room temperature the AHC memorizing about previous irradiation during 20 h

  4. Syntheses, structural analyses and luminescent property of four alkaline-earth coordination polymers

    International Nuclear Information System (INIS)

    Zhang, Sheng; Qu, Xiao-Ni; Xie, Gang; Wei, Qing; Chen, San-Ping

    2014-01-01

    Four alkaline-earth coordination polymers, [Ba(Pzdc)(H 2 O)] n (1), [Ba(Pzdc)] n (2), [AgSr(Pzdc)(NO 3 )(H 2 O)] n (3), [Ag 2 Ca(Pzdc) 2 (H 2 O)] n (4) (H 2 Pzdc=2, 3-pyrazinedicarboxylic acid) have been synthesized and characterized by single-crystal X-ray diffraction. Compounds 1 and 2 afford 2D layer networks generated by one-dimensional chains containing the [Ba 2 O 11 N] units. Compound 3 is of 2D mixed-metal coordination network formed by one-dimensional chain units, while 4 is of a 3D heterometallic framework. Interestingly, 1 and 2 can undergo reversible SCSC structural transformation upon dehydration/rehydration of coordinated water molecules. In addition, the π–π stacking interactions dominate fluorescent properties of compounds 1 and 2. - Graphical abstract: Four new coordination polymers [Ba(Pzdc)(H 2 O)] n (1), [Ba(Pzdc)] n (2), [AgSr(Pzdc)(NO 3 )(H 2 O)] n (3), [Ag 2 Ca(Pzdc) 2 (H 2 O)] n (4) (H 2 Pzdc=2, 3-pyrazinedicarboxylic acid) have been synthesized. Compounds 1–3 display 2D topology structures and compound 4 exhibits a 3D topology structure. Fortunately, 1 and 2 undergo reversible dehydration/rehydration of coordinated water molecules. Display Omitted - Highlights: • All structures are generated by 1D chains. • 1 and 2 show reversible dehydration/rehydration of coordinated water molecules. • The π–π stacking interactions dominate fluorescent properties of compounds 1 and 2

  5. Syntheses, structural analyses and luminescent property of four alkaline-earth coordination polymers

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Sheng; Qu, Xiao-Ni; Xie, Gang; Wei, Qing; Chen, San-Ping, E-mail: sanpingchen@126.com

    2014-02-15

    Four alkaline-earth coordination polymers, [Ba(Pzdc)(H{sub 2}O)]{sub n} (1), [Ba(Pzdc)]{sub n} (2), [AgSr(Pzdc)(NO{sub 3})(H{sub 2}O)]{sub n} (3), [Ag{sub 2}Ca(Pzdc){sub 2}(H{sub 2}O)]{sub n} (4) (H{sub 2}Pzdc=2, 3-pyrazinedicarboxylic acid) have been synthesized and characterized by single-crystal X-ray diffraction. Compounds 1 and 2 afford 2D layer networks generated by one-dimensional chains containing the [Ba{sub 2}O{sub 11}N] units. Compound 3 is of 2D mixed-metal coordination network formed by one-dimensional chain units, while 4 is of a 3D heterometallic framework. Interestingly, 1 and 2 can undergo reversible SCSC structural transformation upon dehydration/rehydration of coordinated water molecules. In addition, the π–π stacking interactions dominate fluorescent properties of compounds 1 and 2. - Graphical abstract: Four new coordination polymers [Ba(Pzdc)(H{sub 2}O)]{sub n} (1), [Ba(Pzdc)]{sub n} (2), [AgSr(Pzdc)(NO{sub 3})(H{sub 2}O)]{sub n} (3), [Ag{sub 2}Ca(Pzdc){sub 2}(H{sub 2}O)]{sub n} (4) (H{sub 2}Pzdc=2, 3-pyrazinedicarboxylic acid) have been synthesized. Compounds 1–3 display 2D topology structures and compound 4 exhibits a 3D topology structure. Fortunately, 1 and 2 undergo reversible dehydration/rehydration of coordinated water molecules. Display Omitted - Highlights: • All structures are generated by 1D chains. • 1 and 2 show reversible dehydration/rehydration of coordinated water molecules. • The π–π stacking interactions dominate fluorescent properties of compounds 1 and 2.

  6. Creating high yield water soluble luminescent graphene quantum dots via exfoliating and disintegrating carbon nanotubes and graphite flakes.

    Science.gov (United States)

    Lin, Liangxu; Zhang, Shaowei

    2012-10-21

    We have developed an effective method to exfoliate and disintegrate multi-walled carbon nanotubes and graphite flakes. With this technique, high yield production of luminescent graphene quantum dots with high quantum yield and low oxidization can be achieved.

  7. Holographic patterning of luminescent photopolymer nanocomposites

    International Nuclear Information System (INIS)

    Sakhno, Oksana V.; Smirnova, Tatiana N.; Goldenberg, Leonid M.; Stumpe, Joachim

    2008-01-01

    Volume phase gratings in the photopolymerisable composites, containing luminescent nanoparticles have been fabricated for the first time. Nanoparticles of LaPO 4 , doped by Ce 3+ and Tb 3+ ions (the trade name is REN-X-green) with high luminescence quantum yield were used as a luminescent inorganic additive. The holographic gratings in such materials are formed as a result of the diffusion distribution of the nanoparticles during exposure of photopolymerisable composites to interference pattern. The influence of the pre-polymer formulation and the holographic patterning parameters on the grating formation is comprehensively investigated. The use of the optimised pre-polymer syrup containing two monomers with sufficiently different polymerisation rates allows fabrication of gratings with diffraction efficiency up to 80% at low optical losses (< 5%) (20 μm film thickness). To obtain maximum diffraction efficiency the intensity and the period of the interference pattern were optimised for each formulation. In addition maximum diffraction efficiency was achieved with the nanocomposites containing 30-32 wt.% of nanoparticles. On the other hand the highest possible modulation of the nanoparticles' concentration was obtained for the concentration of about 20 wt.%. In this case maximum ordering of the nanoparticles in the polymer matrix is achieved. The photoluminescence of the nanoparticles within the homogeneous polymer film and within the grating has been measured. The example application of the photopolymerisable composite containing luminescence inorganic nanoparticles in holographic security technology has been demonstrated

  8. Luminescent screens

    International Nuclear Information System (INIS)

    Lu, C.-I.

    1982-01-01

    Luminescent screens which are useful for such purposes as intensifying screens for radiographs are comprised of a support bearing a layer of finely divided particles of a phosphor dispersed in a cross-linked polymeric matrix formed by heat-curing of a coating composition comprising an unsaturated cross-linkable polymer, a polymerizable acrylic monomer, a thermoplastic polyurethane elastomer, and a heat-activatable polymerization initiator. The phosphor layer includes voids formed by evaporation of an evaporable component which is present in the coating composition from which such layer is formed. (author)

  9. Fluorinated Poly(p-phenylenevinylenes: Synthesis and Optical Properties of an Intriguing Class of Luminescent Polymers

    Directory of Open Access Journals (Sweden)

    Gianluca M. Farinola

    2010-05-01

    Full Text Available This review is an overview of our previous work on the synthesis and properties of poly(p-phenylenevinylenes (PPVs selectively fluorinated in different positions of the conjugated backbone. Both the synthetic challenges and the effects of functionalization with fluorine atoms on the optical behavior are discussed, highlighting the peculiarities and the interest of this class of conjugated polymers. A general polymerization protocol for PPVs, that is based on the Pd-catalyzed Stille cross-coupling reaction of bis-stannylated vinylene monomers with aromatic bis-halides, has been successfully extended to the synthesis of selectively fluorinated poly(p-phenylenevinylenes. The properties of a series of these PPVs differing in the number and positions of the fluorine atoms on the conjugated backbone have been studied, even in comparison with the non-fluorinated counterparts. The intriguing optical features of the resulting materials are discussed considering not only the role of the electronic and steric effects induced by the fluorine substituents, but also the impact of the fluorination on the solid state organization and intermolecular interactions.

  10. Homogeneous Synthesis and Electroluminescence Device of Highly Luminescent CsPbBr3 Perovskite Nanocrystals.

    Science.gov (United States)

    Wei, Song; Yang, Yanchun; Kang, Xiaojiao; Wang, Lan; Huang, Lijian; Pan, Daocheng

    2017-03-06

    Highly luminescent CsPbBr 3 perovskite nanocrystals (PNCs) are homogeneously synthesized by mixing toluene solutions of PbBr 2 and cesium oleate at room temperature in open air. We found that PbBr 2 can be easily dissolved in nonpolar toluene in the presence of tetraoctylammonium bromide, which allows us to homogeneously prepare CsPbBr 3 perovskite quantum dots and prevents the use of harmful polar organic solvents, such as N,N-dimethylformamide, dimethyl sulfoxide, and N-methyl-2-pyrrolidone. Additionally, this method can be extended to synthesize highly luminescent CH 3 NH 3 PbBr 3 perovskite quantum dots. An electroluminescence device with a maximal luminance of 110 cd/m 2 has been fabricated by using high-quality CsPbBr 3 PNCs as the emitting layer.

  11. Design, synthesis and characterization of a highly luminescent Eu-complex monomer featuring thenoyltrifluoroacetone and 5-acryloxyethoxymethyl-8-hydroxyquinoline

    Energy Technology Data Exchange (ETDEWEB)

    Xu Cunjin [State Key Laboratory of Chemical Engineering, Department of Chemical and Biochemical Engineering, Zhejiang University, Hangzhou 310027 (China); College of Material, Chemistry and Chemical Engineering, Hangzhou Normal University, Hangzhou 310036 (China); Li Bogeng, E-mail: bgli@zju.edu.cn [State Key Laboratory of Chemical Engineering, Department of Chemical and Biochemical Engineering, Zhejiang University, Hangzhou 310027 (China); Wan Jintao; Bu Zhiyang [State Key Laboratory of Chemical Engineering, Department of Chemical and Biochemical Engineering, Zhejiang University, Hangzhou 310027 (China)

    2011-08-15

    A multi-functional ligand, 5-acryloxyethoxymethyl-8-hydroxyquinoline (Hamq), was synthesized, which contained a polymerizable C=C double bond for the copolymerization with other vinyl monomers and acted as photon antenna able to transfer energy to Eu{sup 3+} ions effectively. The triplet state energy of Hamq was determined to be 22,370 cm{sup -1} via the phosphorescence spectra of Hamq and its gadolinium complex. The title complex monomer Eu(tta){sub 2}(amq) was prepared by coordination reaction of Hamq with europium isopropoxide and 2-thenoyltrifluoroacetone (Htta) in dry organic solvents under argon atmosphere and characterized by elemental analysis and IR spectrum. The photophysical properties of the complex were studied in detail with UV-vis, luminescence spectra, luminescence lifetime and quantum yield. The complex exhibited nearly monochromatic red emission at 612 nm, a remarkable luminescence quantum yield at room temperature (30.6%) upon ligand excitation and a long {sup 5}D{sub 0} lifetime (389 {mu}s), which indicated that the ligand Hamq could sensitize the luminescence of Eu(III) ion efficiently in Eu(tta){sub 2}(amq), resulting in a strong luminescence of its copolymer poly[MMA-co-Eu(TTA){sub 2}(amq)] under UV excitation. The excellent luminescence properties of the complex made it not only a promising light-conversion molecular device but also an excellent luminescent monomer. - Highlights: >iWe designed and synthesized a highly luminescent Eu-complex monomer. > Quantum yield and lifetime of the complex are 30.6% and 389 {mu}s, respectively. > Excellent luminescence of the complex made it an excellent luminescent monomer.

  12. A new (4, 6)-connected Cu(I) coordination polymer based on rare tetranuclear [Cu4I2] clusters: Synthesis, crystal structure, luminescent and photocatalytic properties

    Science.gov (United States)

    Cui, Li-Jing; Liu, Chun-Yan; Bian, Ming; Yu, Li-Jun

    2018-03-01

    A new Cu(I) coordination polymer, namely [Cu5I3(L)2]n (1 HL = 3-(4-pyridyl)-5-(3-pyridyl)-1,2,4-triazolyl), was solvothermally synthesized using CuI, HL and NaI as the starting materials. Single crystal X-ray structural analysis shows that compound 1 features a (4, 6)-connected 3D framework employing rare tetranuclear [Cu4I2] clusters as building subunits. It exhibits intense metal-to-ligand luminescence and excellent photocatalytic activity on degradation of methylene blue (MB).

  13. Influence of dehydrated nanotubed titanic acid on charge transport and luminescent properties of polymer light-emitting diodes with fluorescent dye

    Science.gov (United States)

    Qian, Lei; Bera, Debasis; Jin, Zhen-Sheng; Du, Zu-Liang; Xu, Zheng; Teng, Feng; Liu, Wei

    2007-09-01

    In this paper, we discuss the influence of dehydrated nanotubed titanic acid (DNTA) on charge transport and luminescent properties of polymer light-emitting diodes (PLEDs) doped with fluorescent dye. Photoluminescence results confirm the efficient energy transfer from PVK to 4-(dicyanom-ethylene)-2- t-butyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran (DCJTB) and tris-(8-hydroxtquinoline) aluminum (Alq 3) in a DNTA-doped device. The device showed lower turn-on voltages and higher charge current by doping with DNTA, which also caused a shift in the exciton's recombination region.

  14. High-density polymer microarrays: identifying synthetic polymers that control human embryonic stem cell growth.

    Science.gov (United States)

    Hansen, Anne; Mjoseng, Heidi K; Zhang, Rong; Kalloudis, Michail; Koutsos, Vasileios; de Sousa, Paul A; Bradley, Mark

    2014-06-01

    The fabrication of high-density polymer microarray is described, allowing the simultaneous and efficient evaluation of more than 7000 different polymers in a single-cellular-based screen. These high-density polymer arrays are applied in the search for synthetic substrates for hESCs culture. Up-scaling of the identified hit polymers enables long-term cellular cultivation and promoted successful stem-cell maintenance. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Effect of High-Temperature Annealing on Yellow and Blue Luminescence of Undoped GaN

    International Nuclear Information System (INIS)

    Chai Xu-Zhao; Zhou Dong; Liu Bin; Xie Zi-Li; Han Ping; Xiu Xiang-Qian; Chen Peng; Lu Hai; Zhang Rong; Zheng You-Dou

    2015-01-01

    The effect of high-temperature annealing on the yellow and blue luminescence of the undoped GaN is investigated by photoluminescence (PL) and x-ray photoelectron spectroscopy (XPS). It is found that the band-edge emission in the GaN apparently increases, and the yellow luminescence (YL) and blue luminescence (BL) bands dramatically decrease after annealing at 700°C. At the annealing temperature higher than 900°C, the YL and BL intensities show an enhancement for the nitrogen annealed GaN. This fact should be attributed to the increment of the Ga and N vacancies in the GaN decomposition. However, the integrated PL intensity of the oxygen annealed GaN decreases at the temperature ranging from 900°C to 1000°C. This results from the capture of many photo-generated holes by high-density surface states. XPS characterization confirms that the high-density surface states mainly originate from the incorporation of oxygen atoms into GaN at the high annealing temperature, and even induces the 0.34eV increment of the upward band bending for the oxygen annealed GaN at 1000°C. (paper)

  16. Conformal and highly luminescent monolayers of Alq3 prepared by gas-phase molecular layer deposition.

    Science.gov (United States)

    Räupke, André; Albrecht, Fabian; Maibach, Julia; Behrendt, Andreas; Polywka, Andreas; Heiderhoff, Ralf; Helzel, Jonatan; Rabe, Torsten; Johannes, Hans-Hermann; Kowalsky, Wolfgang; Mankel, Eric; Mayer, Thomas; Görrn, Patrick; Riedl, Thomas

    2014-01-22

    The gas-phase molecular layer deposition (MLD) of conformal and highly luminescent monolayers of tris(8-hydroxyquinolinato)aluminum (Alq3) is reported. The controlled formation of Alq3 monolayers is achieved for the first time by functionalization of the substrate with amino groups, which serve as initial docking sites for trimethyl aluminum (TMA) molecules binding datively to the amine. Thereby, upon exposure to 8-hydroxyquinoline (8-HQ), the self-limiting formation of highly luminescent Alq3 monolayers is afforded. The growth process and monolayer formation were studied and verified by in situ quartz crystal monitoring, optical emission and absorption spectroscopy, and X-ray photoelectron spectroscopy. The nature of the MLD process provides an avenue to coat arbitrarily shaped 3D surfaces and porous structures with high surface areas, as demonstrated in this work for silica aerogels. The concept presented here paves the way to highly sensitive luminescent sensors and dye-sensitized metal oxides for future applications (e.g., in photocatalysis and solar cells).

  17. High resolution NMR spectroscopy of synthetic polymers in bulk

    International Nuclear Information System (INIS)

    Komorski, R.A.

    1986-01-01

    The contents of this book are: Overview of high-resolution NMR of solid polymers; High-resolution NMR of glassy amorphous polymers; Carbon-13 solid-state NMR of semicrystalline polymers; Conformational analysis of polymers of solid-state NMR; High-resolution NMR studies of oriented polymers; High-resolution solid-state NMR of protons in polymers; and Deuterium NMR of solid polymers. This work brings together the various approaches for high-resolution NMR studies of bulk polymers into one volume. Heavy emphasis is, of course, given to 13C NMR studies both above and below Tg. Standard high-power pulse and wide-line techniques are not covered

  18. Structural diversity of a series of terpyridyl carboxylate coordination polymers: Luminescent sensor and magnetic properties

    Science.gov (United States)

    Yuan, Fei; Yuan, Chun-Mei; Hu, Huai-Ming; Wang, Ting-Ting; Zhou, Chun-Sheng

    2018-02-01

    Eleven new coordination polymers, [Zn2(ctpy)2(HCOO)2]n·3nH2O (1), [Zn2(ctpy)2(HCOO)2(H2O)2]n·nH2O (2), [Zn2(ctpy)2(H2O)4]n·2n(CH3COO)·nH2O (3), [Zn2(ctpy)2(CH3COO)2]n·nH2O (4), [Zn(ctpy)2]n·nH2O (5), [Zn2(ctpy)2(Hidc)(H2O)2]n(6), [Cd2(ctpy)4]n(7), [Cd2(ctpy)2(Hidc)]n(8), [Co2(ctpy)2(HCOO)2(H2O)2]n·nH2O (9), [Co(ctpy)(DMF)(ox)0.5]n(10), [Co(ctpy)(ox)0.5]n(11) and the closely related compound [Zn(ctpy)(ox)0.5]n·0.5nH2O (12) (Hctpy = 4‧-carboxy-4,2‧:6‧,4‧‧-terpyridine, H2ox = oxalic acid and H3idc = imidazole-4,5-dicarboxylic acid) have been synthesized by hydro(solvo)thermal reaction of 4‧-carboxy-4,2‧:6‧,4‧‧-terpyridine with divalent metal salts and characterized by elemental analysis, IR spectra, single crystal X-ray diffraction. Compounds 1 and 4 have similar structure which demonstrate a two-fold interpenetrating 3D framework with a 3-connected utp topological net, which contains the same number of left and right-handed 21 helical chains. Compounds 2 and 9 are isostructural 2D layer with a 3-connected hcb topological net. Similar to 2, compound 3 also displays a 3-connected 2D hcb topological net. Compounds 5 and 10 are a 2D layer with a 4-connected sql topological net. Compound 6 shows a chiral 2D layer based on a 1D left- or right-handed helical chains, which are further extended into an achiral 2D + 2D→3D supramolecular network by hydrogen bonds with alternately arrangement. Compound 7 features an unusual 2-fold interpenetrating 3D coordination network which exhibits a new intriguing (3,5)-connected binodal topological net with the Schläfli symbol of (52·6)(53·63·73·8). Compound 8 shows a 2D→3D supramolecular structure based on (3,4)-connected 2D bilayers with the Schläfli symbol of (44·62). Compound 11 displays an unusual three-dimensional coordination network which exhibits an intriguing (3,8)-connected binodal new topological net with Schläfli symbol (42·62)2(42·623·83). Compound 12 features a two

  19. Appearance of high submerged cavitating jet: The cavitation phenomenon and sono luminescence

    Directory of Open Access Journals (Sweden)

    Hutli Ezddin

    2013-01-01

    Full Text Available In order to study jet structure and behaviour of cloud cavitation within time and space, visualization of highly submerged cavitating water jet has been done using Stanford Optics 4 Quick 05 equipment, through endoscopes and other lenses with Drello3244 and Strobex Flash Chadwick as flashlight stroboscope. This included obligatory synchronization with several types of techniques and lenses. Images of the flow regime have been taken, allowing calculation of the non-dimensional cavitation cloud length under working conditions. Consequently a certain correlation has been proposed. The influencing parameters, such as; injection pressure, downstream pressure and cavitation number were experimentally proved to be very significant. The recordings of sono-luminescence phenomenon proved the collapsing of bubbles everywhere along the jet trajectory. In addition, the effect of temperature on sono-luminescence recordings was also a point of investigation. [Projekat Ministarstva nauke Republike Srbije, br. TR35046

  20. Highly sensitive time resolved singlet oxygen luminescence detection using LEDs as the excitation source

    International Nuclear Information System (INIS)

    Hackbarth, S; Schlothauer, J; Preuss, A; Röder, B

    2013-01-01

    For the first time singlet oxygen luminescence kinetics in living cells were detected at high precision using LED light for excitation. As LED technology evolves, the light intensity emitted by standard LEDs allows photosensitized singlet oxygen luminescence detection in solution and cell suspensions. We present measurements superior to those of most actual laser powered setups regarding precision of singlet oxygen kinetics in solutions and cell suspensions. Data presented here show that LED based setups allow the determination of the photosensitizer triplet and singlet oxygen decay times in vitro with an accuracy of 0.1 μs. This enables monitoring of the photosensitizer efficiency and interaction with the cellular components using illumination doses small enough not to cause cell death. (letter)

  1. High temperature chemically resistant polymer concrete

    Science.gov (United States)

    Sugama, T.; Kukacka, L.E.

    High temperature chemically resistant, non-aqueous polymer concrete composites consist of about 12 to 20% by weight of a water-insoluble polymer binder. The binder is polymerized in situ from a liquid vinyl-type monomer or mixture of vinyl containing monomers such as triallylcyanurate, styrene, acrylonitrile, acrylamide, methacrylamide, methyl-methacrylate, trimethylolpropane trimethacrylate and divinyl benzene. About 5 to 40% by weight of a reactive inorganic filler selected from the group consisting of tricalcium silicate and dicalcium silicate and mixtures containing less than 2% free lime, and about 48 to 83% by weight of silica sand/ and a free radical initiator such as di-tert-butyl peroxide, azobisisobutyronitrile, benzoyl peroxide, lauryl peroxide, other orgaic peroxides and combinations to initiate polymerization of the monomer in the presence of the inorganic filers are used.

  2. Target-Triggered Switching on and off the Luminescence of Lanthanide Coordination Polymer Nanoparticles for Selective and Sensitive Sensing of Copper Ions in Rat Brain.

    Science.gov (United States)

    Huang, Pengcheng; Wu, Fangying; Mao, Lanqun

    2015-07-07

    Copper ions (Cu(2+)) in the central nervous system play a crucial role in the physiological and pathological events, so simple, selective, and sensitive detection of cerebral Cu(2+) is of great importance. In this work, we report a facile yet effective fluorescent method for sensing of Cu(2+) in rat brain using one kind of lanthanide coordination polymer nanoparticle, adenosine monophosphate (AMP) and terbium ion (Tb(3+)), i.e., AMP-Tb, as the sensing platform. Initially, a cofactor ligand, 5-sulfosalicylic acid (SSA), as the sensitizer, was introduced into the nonluminescent AMP-Tb suspension, resulting in switching on the luminescence of AMP-Tb by the removal of coordinating water molecules and concomitant energy transfer from SSA to Tb(3+). The subsequent addition of Cu(2+) into the resulting SSA/AMP-Tb can strongly quench the fluorescence because the specific coordination interaction between SSA and Cu(2+) rendered energy transfer from SSA to Tb(3+) inefficient. The decrease ratio of the fluorescence intensities of SSA/AMP-Tb at 550 nm show a linear relationship for Cu(2+) within the concentration range from 1.5 to 24 μM with a detection limit of 300 nM. The method demonstrated here is highly selective and is free from the interference of metal ions, amino acids, and the biological species commonly existing in the brain such as dopamine, lactate, and glucose. Eventually, by combining the microdialysis technique, the present method has been successfully applied in the detection of cerebral Cu(2+) in rat brain with the basal dialysate level of 1.91 ± 0.40 μM (n = 3). This method is very promising to be used for investigating the physiological and pathological events that cerebral Cu(2+) participates in.

  3. Highly Sensitive Detection of UV Radiation Using a Uranium Coordination Polymer.

    Science.gov (United States)

    Liu, Wei; Dai, Xing; Xie, Jian; Silver, Mark A; Zhang, Duo; Wang, Yanlong; Cai, Yawen; Diwu, Juan; Wang, Jian; Zhou, Ruhong; Chai, Zhifang; Wang, Shuao

    2018-02-07

    The accurate detection of UV radiation is required in a wide range of chemical industries and environmental or biological related applications. Conventional methods taking advantage of semiconductor photodetectors suffer from several drawbacks such as sophisticated synthesis and manufacturing procedure, not being able to measure the accumulated UV dosage as well as high defect density in the material. Searching for new strategies or materials serving as precise UV dosage sensor with extremely low detection limit is still highly desirable. In this work, a radiation resistant uranium coordination polymer [UO 2 (L)(DMF)] (L = 5-nitroisophthalic acid, DMF = N,N-dimethylformamide, denoted as compound 1) was successfully synthesized through mild solvothermal method and investigated as a unique UV probe with the detection limit of 2.4 × 10 -7 J. On the basis of the UV dosage dependent luminescence spectra, EPR analysis, single crystal structure investigation, and the DFT calculation, the UV-induced radical quenching mechanism was confirmed. Importantly, the generated radicals are of significant stability which offers the opportunity for measuring the accumulated UV radiation dosage. Furthermore, the powder material of compound 1 was further upgraded into membrane material without loss in luminescence intensity to investigate the real application potentials. To the best of our knowledge, compound 1 represents the most sensitive coordination polymer based UV dosage probe reported to date.

  4. A luminescent Lanthanide-free MOF nanohybrid for highly sensitive ratiometric temperature sensing in physiological range.

    Science.gov (United States)

    Zhou, You; Zhang, Denan; Zeng, Jin; Gan, Ning; Cuan, Jing

    2018-05-01

    Luminescent MOF materials with tunable emissions and energy/charge transfer processes have been extensively explored as ratiometric temperature sensors. However, most of the ratiometric MOF thermometers reported thus far are based on the MOFs containing photoactive lanthanides, which are potentially facing cost issue and serious supply shortage. Here, we present a ratiometric luminescent thermometer based on a dual-emitting lanthanide-free MOF hybrid, which is developed by encapsulation of a fluorescent dye into a robust nanocrystalline zirconium-based MOF through a one-pot synthesis approach. The structure and morphology of the hybrid product was characterized by Powder X-ray diffraction (PXRD), N 2 adsorption-desorption measurement and Scanning electron microscopy (SEM). The pore confinement effect well isolates the guest dye molecules and therefore suppresses the nonradiative energy transfer process between dye molecules. The incorporated dye emission is mainly sensitized by the organic linkers within MOF through fluorescence resonance energy transfer. The ratiometric luminescence of the MOF hybrid shows a significant response to temperature due to the thermal-related back energy transfer process from dye molecules and organic linkers, thus can be exploited for self-calibrated temperature sensing. The maximum thermometric sensitivity is 1.19% °C -1 in the physiological temperature range, which is among the highest for the ratiomtric MOF thermometers that operating in 25-45°C. The temperature resolution is better than 0.1°C over the entire operative range (20-60°C). By integrating the advantages of excellent stability, nanoscale nature, and high sensitivity and precision in the physiological temperature range, this dye@MOF hybrid might have potential application in biomedical diagnosis. What' more, this work has expanded the possibility of non-lanthanide luminescent MOF materials for the development of ratiometric temperature sensors. Copyright © 2018

  5. Highly Luminescent Lanthanide Complexes of 1 Hydroxy-2-pyridinones

    Energy Technology Data Exchange (ETDEWEB)

    University of California, Berkeley; Lawrence National Laboratory; Raymond, Kenneth; Moore, Evan G.; Xu, Jide; Jocher, Christoph J.; Castro-Rodriguez, Ingrid; Raymond, Kenneth N.

    2007-11-01

    The synthesis, X-ray structure, stability, and photophysical properties of several trivalent lanthanide complexes formed from two differing bis-bidentate ligands incorporating either alkyl or alkyl ether linkages and featuring the 1-hydroxy-2-pyridinone (1,2-HOPO) chelate group in complex with Eu(III), Sm(III) and Gd(III) are reported. The Eu(III) complexes are among some of the best examples, pairing highly efficient emission ({Phi}{sub tot}{sup Eu} {approx} 21.5%) with high stability (pEu {approx} 18.6) in aqueous solution, and are excellent candidates for use in biological assays. A comparison of the observed behavior of the complexes with differing backbone linkages shows remarkable similarities, both in stability and photophysical properties. Low temperature photophysical measurements for a Gd(III) complex were also used to gain insight into the electronic structure, and were found to agree with corresponding TD-DFT calculations for a model complex. A comparison of the high resolution Eu(III) emission spectra in solution and from single crystals also revealed a more symmetric coordination geometry about the metal ion in solution due to dynamic rotation of the observed solid state structure.

  6. High-Temperature Shape Memory Polymers

    Science.gov (United States)

    Yoonessi, Mitra; Weiss, Robert A.

    2012-01-01

    physical conformation changes when exposed to an external stimulus, such as a change in temperature. Such materials have a permanent shape, but can be reshaped above a critical temperature and fixed into a temporary shape when cooled under stress to below the critical temperature. When reheated above the critical temperature (Tc, also sometimes called the triggering or switching temperature), the materials revert to the permanent shape. The current innovation involves a chemically treated (sulfonated, carboxylated, phosphonated, or other polar function group), high-temperature, semicrystalline thermoplastic poly(ether ether ketone) (Tg .140 C, Tm = 340 C) mix containing organometallic complexes (Zn++, Li+, or other metal, ammonium, or phosphonium salts), or high-temperature ionic liquids (e.g. hexafluorosilicate salt with 1-propyl-3- methyl imidazolium, Tm = 210 C) to form a network where dipolar or ionic interactions between the polymer and the low-molecular-weight or inorganic compound forms a complex that provides a physical crosslink. Hereafter, these compounds will be referred to as "additives". The polymer is semicrystalline, and the high-melt-point crystals provide a temporary crosslink that acts as a permanent crosslink just so long as the melting temperature is not exceeded. In this example case, the melting point is .340 C, and the shape memory critical temperature is between 150 and 250 C. PEEK is an engineering thermoplastic with a high Young fs modulus, nominally 3.6 GPa. An important aspect of the invention is the control of the PEEK functionalization (in this example, the sulfonation degree), and the thermal properties (i.e. melting point) of the additive, which determines the switching temperature. Because the compound is thermoplastic, it can be formed into the "permanent" shape by conventional plastics processing operations. In addition, the compound may be covalently cross - linked after forming the permanent shape by S-PEEK by applying ionizing

  7. A series of Zn/Cd coordination polymers constructed from 1,4-naphthalenedicarboxylate and N-donor ligands: Syntheses, structures and luminescence sensing of Cr{sup 3+} in aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Dong-Cheng [College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070 (China); Key Laboratory for Preparation and Application of Ordered Structural Materials of Guangdong Province, Shantou University, Shantou 515063 (China); Fan, Yan; Si, Chang-Dai; Wu, Ya-Jun; Dong, Xiu-Yan; Yang, Yun-Xia; Yao, Xiao-Qiang [College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070 (China); Liu, Jia-Cheng, E-mail: jcliu8@nwnu.edu.cn [College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070 (China)

    2016-09-15

    A novel series of Zn/Cd coordination polymers based on H{sub 3}L, namely, [Zn{sub 2}(HL){sub 2}(bipy){sub 2}(H{sub 2}O){sub 6}]{sub n} (1), [Zn(HL)(phen)]{sub n} (2), [Cd{sub 3}L{sub 2}(bbi){sub 3}]{sub n} (3), [Zn{sub 3}L{sub 2}(bbi){sub 3}]{sub n} (4) [(H{sub 3}L =4-[(1-carboxynaphthalen-2-yl)oxy]phthalic acid, bipy =4,4′-bipyridine, phen =1,10-phenanthroline, bbi =1,1′-(1,4-butanediyl)bis(imidazole] have been successfully synthesized by solvothermal reaction. Compound 1 possesses two diverse 1D chains constructed by different bipy coligands, which were further connected to form a 3D supramolecular architecture by hydrogen bonding interactions. Compound 2 possesses a complicated 1D chain based on secondary building unit (SBU) with binuclear Zn cluster. Compounds 3 and 4 exhibit similar 2D→3D framework, which can be rationalized as (3,4,4)-connected 3D net with a Schläfli symbol of (6{sup 3}.8.10{sup 2}){sub 2}(6{sup 3}){sub 2}(6{sup 4}.8.10). In particular, compound 3 exhibited a high sensitivity for Cr{sup 3+} in aqueous solutions, which suggest that compound 3 is a promising luminescent probe for selectively sensing Cr{sup 3+}. - Graphical abstract: A series of novel Zn/Cd coordination polymers have been successfully synthesized by solvothermal reaction. The unique 3D Cd{sup 2+} polymer containing bbi as second ligand demonstrates high sensitivity for detection of toxic Cr{sup 3+} in aqueous solutions. Display Omitted - Highlights: • π-conjugated semirigid tricarboxylate ligands with naphthalene rings(H{sub 3}L) were rationally designed. • Four Zn/Cd coordination polymers based on H{sub 3}L have been successfully synthesized by solvothermal reaction. • Compound 3 is a promising luminescent probe for selectively sensing Cr{sup 3+} with high sensitivity in aqueous solutions.

  8. New monomers for high performance polymers

    Science.gov (United States)

    Gratz, Roy F.

    1993-01-01

    This laboratory has been concerned with the development of new polymeric materials with high thermo-oxidative stability for use in the aerospace and electronics industries. Currently, there is special emphasis on developing matrix resins and composites for the high speed civil transport (HSCT) program. This application requires polymers that have service lifetimes of 60,000 hr at 350 F (177 C) and that are readily processible into void-free composites, preferably by melt-flow or powder techniques that avoid the use of high boiling solvents. Recent work has focused on copolymers which have thermally stable imide groups separated by flexible arylene ether linkages, some with trifluoromethyl groups attached to the aromatic rings. The presence of trifluoromethyl groups in monomers and polymers often improves their solubility and processibility. The goal of this research was to synthesize several new monomers containing pendant trifluoromethyl groups and to incorporate these monomers into new imide/arylene ether copolymers. Initially, work was begun on the synthesis of three target compounds. The first two, 3,5-dihydroxybenzo trifluoride and 3-amino 5-hydroxybenzo trifluoride, are intermediates in the synthesis of more complex monomers. The third, 3,5-bis (3-amino-phenoxy) benzotrifluoride, is an interesting diamine that could be incorporated into a polyimide directly.

  9. High-Performance CuInS 2 Quantum Dot Laminated Glass Luminescent Solar Concentrators for Windows

    Energy Technology Data Exchange (ETDEWEB)

    Bergren, Matthew R. [UbiQD, Inc., Los Alamos, New Mexico 87544, United States; Makarov, Nikolay S. [UbiQD, Inc., Los Alamos, New Mexico 87544, United States; Ramasamy, Karthik [UbiQD, Inc., Los Alamos, New Mexico 87544, United States; Jackson, Aaron [UbiQD, Inc., Los Alamos, New Mexico 87544, United States; Guglielmetti, Rob [National Renewable Energy Laboratory, Golden, Colorado 80401, United States; McDaniel, Hunter [UbiQD, Inc., Los Alamos, New Mexico 87544, United States

    2018-01-30

    Building-integrated sunlight harvesting utilizing laminated glass luminescent solar concentrators (LSCs) is proposed. By incorporating high quantum yield (>90%), NIR-emitting CuInS2/ZnS quantum dots into the polymer interlayer between two sheets of low-iron float glass, a record optical efficiency of 8.1% is demonstrated for a 10 cm x 10 cm device that transmits ~44% visible light. After completing prototypes by attaching silicon solar cells along the perimeter of the device, the electrical power conversion efficiency was certified at 2.2% with a black background and at 2.9% using a reflective substrate. This 'drop-in' LSC solution is particularly attractive because it fits within the existing glazing industry value chain with only modest changes to typical glazing products. Performance modeling predicts >1 GWh annual electricity production for a typical urban skyscraper in most major U.S. cities, enabling significant energy cost savings and potentially 'net-zero' buildings.

  10. Organic polymers used at high temperatures

    International Nuclear Information System (INIS)

    1983-01-01

    In this book structure and properties of heat resistant polymers are examined. The more recent industrial polymers are presented. Applications in electronic, electrotechnic, space and energy are reviewed in particular geothermy, well drilling, hydrogen production and nuclear energy [fr

  11. High Pressure and Temperature Effects in Polymers

    Science.gov (United States)

    Bucknall, David; Arrighi, Valeria; Johnston, Kim; Condie, Iain

    Elastomers are widely exploited as the basis for seals in gas and fluid pipelines. The underlying behaviour of these elastomer at the high pressure, elevated temperatures they experience in operation is poorly understood. Consequently, the duty cycle of these materials is often deliberately limited to a few hours, and in order to prevent failure, production is stopped in order to change the seals in critical joints. The result is significant time lost due to bringing down production to change the seals as well as knock on financial costs. In order to address the fundamental nature of the elastomers at their intended operating conditions, we are studying the gas permeation behaviour of hydrogenated natural butyl rubber (HNBR) and fluorinated elastomers (FKM) at a high pressure and elevated temperature. We have developed a pressure system that permits gas permeation studies at gas pressures of up to 5000 psi and operating temperatures up to 150° C. In this paper, we will discuss the nature of the permeation behaviour at these extreme operating conditions, and how this relates to the changes in the polymer structure. We will also discuss the use of graphene-polymer thin layer coatings to modify the gas permeation behaviour of the elastomers.

  12. Bioinspired phospholipid polymer biomaterials for making high performance artificial organs

    Directory of Open Access Journals (Sweden)

    K Ishihara

    2000-01-01

    Full Text Available Novel polymer biomaterials, which can be used in contact with blood, are prepared with strong inspiration from the surface structure of biomembrane. That is, the polymers with a phospholipid polar group in the side chain, 2-methacrylooyloxyethyl phosphorylcholine (MPC polymers were synthesized. The MPC polymers can inhibit surface-induced clot formation effectively, when they are in contact with blood even in the absence of an anticoagulant. This phenomenon was due to the reduction of plasma protein and suppression of denaturation of adsorbed proteins, that is the MPC polymers interact with blood components very mildly. As the molecular structure of the MPC polymer was easily designed by changing the monomer units and their composition, it could be applied to surface modification of artificial organs and biomedical devices for improving blood and tissue compatibility. Thus, the MPC polymers are useful polymer biomaterials for manufacturing high performance artificial organs and biomedical devices to provide safe medical treatments.

  13. Luminescent Hydrogel Particles Prepared by Self-Assembly of β-Cyclodextrin Polymer and Octahedral Molybdenum Cluster Complexes

    Czech Academy of Sciences Publication Activity Database

    Kirakci, Kaplan; Šícha, Václav; Holub, Josef; Kubát, Pavel; Lang, Kamil

    2014-01-01

    Roč. 53, č. 24 (2014), s. 13012-13018 ISSN 0020-1669 R&D Projects: GA ČR GA13-05114S Institutional support: RVO:61388980 ; RVO:61388955 Keywords : Octahedral Molybdenum Cluster * Hydrogel * Luminescence Subject RIV: CA - Inorganic Chemistry Impact factor: 4.762, year: 2014

  14. Preparation and luminescent properties of the novel polymer-rare earth complexes composed of Poly(ethylene-co-acrylic acid) and Europium ions

    Science.gov (United States)

    Wu, Yuewen; Hao, Haixia; Wu, Qingyao; Gao, Zihan; Xie, Hongde

    2018-06-01

    A series of novel polymer-rare earth complexes with Eu3+ ions have been synthesized and investigated successfully, including the binary complexes containing the single ligand poly(ethylene-co-acrylic acid) (EAA) and the ternary complexes using 1,10-phenanthroline (phen), dibenzoylmethane (DBM) or thenoyltrifluoroacetone (TTA) as the second ligand. Their structures have been characterized by Fourier transform infrared spectroscopy (FT-IR), elemental analysis and X-ray diffraction (XRD), which confirm that both EAA and small molecules participate in the coordination reaction with rare earth ions, and they can disperse homogeneously in the polymer matrixes. Both ultraviolet-visible (UV-vis) absorption and photoluminescence tests for the complexes have been recorded. The relationship between fluorescence intensity of polymer-rare earth complexes and the quantity of ligand EAA has been studied and discussed. The films casted from the complexes solution can emit strong characteristic red light under UV light excitation. All these results suggest that the complexes possess potential application as luminescent materials.

  15. Synthesis and spectroscopic behavior of highly luminescent trinuclear europium complexes with tris-β-diketone ligand

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Dunjia, E-mail: dunjiawang@163.com; Pi, Yan; Liu, Hua; Wei, Xianhong; Hu, Yanjun; Zheng, Jing

    2014-11-15

    Highlights: • Synthesis of the tris-β-diketone ligand and its trinuclear europium complexes. • Photoluminescence behavior of trinuclear europium complexes. • Analysis of the Judd–Ofelt intensity parameters (Ω{sub t}), lifetime (τ) and quantum yield (η). - Abstract: A new tris-β-diketone ligand, 2-[4,6-bis-(1-benzoyl-2-oxo-2-phenyl-ethyl)-[1,3,5]triazin-2-yl] -1,3-diphenyl-propane-1,3-dione (H{sub 3}L), and its trinuclear europium complexes, Eu{sub 3}(DBM){sub 6}L (C1), Eu{sub 3}(DBM){sub 6}(Bipy){sub 3}L (C2) and Eu{sub 3}(DBM){sub 6}(Phen){sub 3}L (C3) were synthesized and their spectroscopic behaviors were studied by FT-IR, {sup 1}H NMR, UV–vis and photoluminescence spectroscopic techniques. These europium complexes exhibited the characteristic emission bands that arise from the {sup 5}D{sub 0} → {sup 7}F{sub J} (J = 0–4) transitions of the europium ion in solid state. The Ω{sub 2} and Ω{sub 4} intensity parameters, lifetime (τ) and luminescence quantum yield (η) were calculated according to the emission spectra and luminescence decay curves in solid state. The results indicated that these trinuclear europium complexes displayed a longer lifetime (τ) and higher luminescence quantum efficiency (η), especially complexes C2 (τ = 0.820 ms, η = 46.5%) and C3 (τ = 0.804 ms, η = 47.4%), which due to the effect of two additional europium ion lumophors and the introduction of the third ligands, Bipy or Phen in trinuclear complexes. Their Ω{sub 2} values demonstrated that the europium ion in these complexes is in a highly polarizable chemical environment.

  16. A two-dimensional zinc(II) coordination polymer based on mixed dimethyl succinate and bipyridine ligands: synthesis, structure, thermostability and luminescence properties.

    Science.gov (United States)

    Liu, Yang; Feng, Yong Lan; Fu, Wei Wei

    2016-04-01

    From the viewpoint of crystal engineering, the construction of crystalline polymeric materials requires a rational choice of organic bridging ligands for the self-assembly process. Multicarboxylate ligands are of particular interest due to their strong coordination activity towards metal ions, as well as their various coordination modes and versatile conformations. The structural chemistry of dicarboxylate-based coordination polymers of transition metals has been developed through the grafting of N-containing organic linkers into carboxylate-bridged transition metal networks. A new luminescent two-dimensional zinc(II) coordination polymer containing bridging 2,2-dimethylsuccinate and 4,4'-bipyridine ligands, namely poly[[aqua(μ2-4,4'-bipyridine-κ(2)N:N')bis(μ3-2,2-dimethylbutanedioato)-κ(4)O(1),O(1'):O(4):O(4');κ(5)O(1):O(1),O(4):O(4),O(4')-dizinc(II)] dihydrate], {[Zn2(C6H8O4)2(C10H8N2)(H2O)]·2H2O}n, has been synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction and elemental, IR and thermogravimetric analyses. In the structure, the 2,2-dimethylsuccinate ligands link linear tetranuclear Zn(II) subunits into one-dimensional chains along the c axis. 4,4'-Bipyridine acts as a tethering ligand expanding these one-dimensional chains into a two-dimensional layered structure. Hydrogen-bonding interactions between the water molecules (both coordinated and free) and carboxylate O atoms strengthen the packing of the layers. Furthermore, the luminescence properties of the complex were investigated. The compound exhibits a blue photoluminescence in the solid state at room temperature and may be a good candidate for potential hybrid inorganic-organic photoactive materials.

  17. High Temperature Polymer Electrolyte Fuel Cells

    DEFF Research Database (Denmark)

    Fleige, Michael

    This thesis presents the development and application of electrochemical half-cell setups to study the catalytic reactions taking place in High Temperature Polymer Electrolyte Fuel Cells (HTPEM-FCs): (i) a pressurized electrochemical cell with integrated magnetically coupled rotating disk electrode...... oxidation of ethanol is in principle a promising concept to supply HTPEM-FCs with a sustainable and on large scale available fuel (ethanol from biomass). However, the intermediate temperature tests in the GDE setup show that even on Pt-based catalysts the reaction rates become first significant...... at potentials, which approach the usual cathode potentials of HTPEM-FCs. Therefore, it seems that H3PO4-based fuel cells are not much suited to efficiently convert ethanol in accordance with findings in earlier research papers. Given that HTPEM-FCs can tolerate CO containing reformate gas, focusing research...

  18. Surface grafting of zwitterionic polymers onto dye doped AIE-active luminescent silica nanoparticles through surface-initiated ATRP for biological imaging applications

    Science.gov (United States)

    Mao, Liucheng; Liu, Xinhua; Liu, Meiying; Huang, Long; Xu, Dazhuang; Jiang, Ruming; Huang, Qiang; Wen, Yuanqing; Zhang, Xiaoyong; Wei, Yen

    2017-10-01

    Aggregation-induced emission (AIE) dyes have recently been intensively explored for biological imaging applications owing to their outstanding optical feature as compared with conventional organic dyes. The AIE-active luminescent silica nanoparticles (LSNPs) are expected to combine the advantages both of silica nanoparticles and AIE-active dyes. Although the AIE-active LSNPs have been prepared previously, surface modification of these AIE-active LSNPs with functional polymers has not been reported thus far. In this work, we reported a rather facile and general strategy for preparation of polymers functionalized AIE-active LSNPs through the surface-initiated atom transfer radical polymerization (ATRP). The AIE-active LSNPs were fabricated via direct encapsulation of AIE-active dye into silica nanoparticles through a non-covalent modified Stöber method. The ATRP initiator was subsequently immobilized onto these AIE-active LSNPs through amidation reaction between 3-aminopropyl-triethoxy-silane and 2-bromoisobutyryl bromide. Finally, the zwitterionic 2-(methacryloyloxy)ethyl phosphorylcholine (MPC) was selected as model monomer and grafted onto MSNs through ATRP. The characterization results suggested that LSNPs can be successfully modified with poly(MPC) through surface-initiated ATRP. The biological evaluation results demonstrated that the final SNPs-AIE-pMPC composites possess low cytotoxicity, desirable optical properties and great potential for biological imaging. Taken together, we demonstrated that AIE-active LSNPs can be fabricated and surface modified with functional polymers to endow novel functions and better performance for biomedical applications. More importantly, this strategy developed in this work could also be extended for fabrication of many other LSNPs polymer composites owing to the good monomer adoptability of ATRP.

  19. Highly Luminescent, Water-Soluble Lanthanide Fluorobenzoates: Syntheses, Structures and Photophysics, Part I: Lanthanide Pentafluorobenzoates.

    Science.gov (United States)

    Kalyakina, Alena S; Utochnikova, Valentina V; Bushmarinov, Ivan S; Ananyev, Ivan V; Eremenko, Igor L; Volz, Daniel; Rönicke, Franziska; Schepers, Ute; Van Deun, Rik; Trigub, Alexander L; Zubavichus, Yan V; Kuzmina, Natalia P; Bräse, Stefan

    2015-12-01

    Highly luminescent, photostable, and soluble lanthanide pentafluorobenzoates have been synthesized and thoroughly characterized, with a focus on Eu(III) and Tb(III) complexes as visible emitters and Nd(III) , Er(III) , and Yb(III) complexes as infrared emitters. Investigation of the crystal structures of the complexes in powder form and as single crystals by using X-ray diffraction revealed five different structural types, including monomeric, dimeric, and polymeric. The local structure in different solutions was studied by using X-ray absorption spectroscopy. The photoluminescence quantum yields (PLQYs) of terbium and europium complexes were 39 and 15 %, respectively; the latter value was increased almost twice by using the heterometallic complex [Tb0.5 Eu0.5 (pfb)3 (H2 O)] (Hpfb=pentafluorobenzoic acid). Due to the effectively utilized sensitization strategy (pfb)(-) →Tb→Eu, a pure europium luminescence with a PLQY of 29 % was achieved. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Use of a highly sensitive two-dimensional luminescence imaging system to monitor endogenous bioluminescence in plant leaves

    Directory of Open Access Journals (Sweden)

    Flor-Henry Michel

    2004-11-01

    Full Text Available Abstract Background All living organisms emit spontaneous low-level bioluminescence, which can be increased in response to stress. Methods for imaging this ultra-weak luminescence have previously been limited by the sensitivity of the detection systems used. Results We developed a novel configuration of a cooled charge-coupled device (CCD for 2-dimensional imaging of light emission from biological material. In this study, we imaged photon emission from plant leaves. The equipment allowed short integration times for image acquisition, providing high resolution spatial and temporal information on bioluminescence. We were able to carry out time course imaging of both delayed chlorophyll fluorescence from whole leaves, and of low level wound-induced luminescence that we showed to be localised to sites of tissue damage. We found that wound-induced luminescence was chlorophyll-dependent and was enhanced at higher temperatures. Conclusions The data gathered on plant bioluminescence illustrate that the equipment described here represents an improvement in 2-dimensional luminescence imaging technology. Using this system, we identify chlorophyll as the origin of wound-induced luminescence from leaves.

  1. Radioresistance increase in polymers at high pressures. [. gamma. rays

    Energy Technology Data Exchange (ETDEWEB)

    Milinchuk, V; KIRJUKHIN, V; KLINSHPONT, E

    1977-06-01

    The effect was studied of very high pressures ranging within 100 and 2,700 MPa on the radioresistance of polytetrafluoroethylene, polypropylene and polyethylene in gamma irradiation. For experiments industrial polymers in the shape of blocks, films and fibers were used. It is shown that in easily breakable polymers, such as polytetrafluoroethylene and polypropylene, 1.3 to 2 times less free radicals are formed as a result of gamma irradiation and a pressure of 150 MPa than at normal pressure. The considerably reduced radiation-chemical formation of radicals and the destruction suppression by cross-linking in polymers is the evidence of the polymer radioresistance in irradiation at high pressures.

  2. Ultrasensitive direct competitive FLISA using highly luminescent quantum dot beads for tuning affinity of competing antigens to antibodies

    Energy Technology Data Exchange (ETDEWEB)

    Xiong, Sicheng; Zhou, Yaofeng; Huang, Xiaolin [State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047 (China); Yu, Ruijin [College of Science, Northwest A& F University, Yangling, Shaanxi 712100 (China); Lai, Weihua [State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047 (China); Xiong, Yonghua, E-mail: yhxiongchen@163.com [State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047 (China)

    2017-06-15

    Herein, for the first time we report a novel direct competitive fluorescence-linked immunosorbent assay (dcFLISA) for the ultrasensitive detection of ochratoxin A (OTA) by introducing a large size polymer beads loaded with quantum dots (QBs) as carrier of competing antigen for decreasing binding affinity to antibody and enhancing the fluorescent signal intensity. When using 255 nm QBs as carrier of competing antigen, the equilibrium dissociation constant of QB based competing antigen to antibodies can be tuned to 100 times higher than that of the horseradish peroxidase (HRP) based competing antigen by controlling labeled amounts of antigen on the surface of QBs. Various parameters that influenced the sensitivity of dcFLISA were investigated and optimized. Under optimum detection parameters, the dynamic linear range of developed dcFLISA for detecting OTA was established at 0.05 pg/mL to 1.56 pg/mL with a half maximal inhibitory concentration at 0.14 ± 0.04 pg/mL (n = 5), which is three orders of magnitude lower than that of conventional HRP-based dcELISA (0.24 ng/mL). The developed FLISA is also highly accurate, reliable, and shows no cross reaction to other mycotoxins. In summary, the proposed method offers a straightforward approach to improve the sensitivity of direct competitive immunoassay for trace small chemical molecule detection in food quality control, environmental monitoring, and clinical diagnosis. - Highlights: • Highly luminescent QBs were used as a carrier of competing antigen for ultrasensitive detection of OTA. • It is the first time to use a large size QBs as a carrier for tuning affinity of competing antigen to antibodies. • IC{sub 50} value of QB-based dcFLISA is three orders of magnitude lower than that of HRP-based dcELISA.

  3. Ultrasensitive direct competitive FLISA using highly luminescent quantum dot beads for tuning affinity of competing antigens to antibodies

    International Nuclear Information System (INIS)

    Xiong, Sicheng; Zhou, Yaofeng; Huang, Xiaolin; Yu, Ruijin; Lai, Weihua; Xiong, Yonghua

    2017-01-01

    Herein, for the first time we report a novel direct competitive fluorescence-linked immunosorbent assay (dcFLISA) for the ultrasensitive detection of ochratoxin A (OTA) by introducing a large size polymer beads loaded with quantum dots (QBs) as carrier of competing antigen for decreasing binding affinity to antibody and enhancing the fluorescent signal intensity. When using 255 nm QBs as carrier of competing antigen, the equilibrium dissociation constant of QB based competing antigen to antibodies can be tuned to 100 times higher than that of the horseradish peroxidase (HRP) based competing antigen by controlling labeled amounts of antigen on the surface of QBs. Various parameters that influenced the sensitivity of dcFLISA were investigated and optimized. Under optimum detection parameters, the dynamic linear range of developed dcFLISA for detecting OTA was established at 0.05 pg/mL to 1.56 pg/mL with a half maximal inhibitory concentration at 0.14 ± 0.04 pg/mL (n = 5), which is three orders of magnitude lower than that of conventional HRP-based dcELISA (0.24 ng/mL). The developed FLISA is also highly accurate, reliable, and shows no cross reaction to other mycotoxins. In summary, the proposed method offers a straightforward approach to improve the sensitivity of direct competitive immunoassay for trace small chemical molecule detection in food quality control, environmental monitoring, and clinical diagnosis. - Highlights: • Highly luminescent QBs were used as a carrier of competing antigen for ultrasensitive detection of OTA. • It is the first time to use a large size QBs as a carrier for tuning affinity of competing antigen to antibodies. • IC_5_0 value of QB-based dcFLISA is three orders of magnitude lower than that of HRP-based dcELISA.

  4. Cultivating Fluorescent Flowers with Highly Luminescent Carbon Dots Fabricated by a Double Passivation Method.

    Science.gov (United States)

    Han, Shuai; Chang, Tao; Zhao, Haiping; Du, Huanhuan; Liu, Shan; Wu, Baoshuang; Qin, Shenjun

    2017-07-07

    In this work, we present the fabrication of highly luminescent carbon dots (CDs) by a double passivation method with the assistance of Ca(OH)₂. In the reaction process, Ca 2+ protects the active functional groups from overconsumption during dehydration and carbonization, and the electron-withdrawing groups on the CD surface are converted to electron-donating groups by the hydroxyl ions. As a result, the fluorescence quantum yield of the CDs was found to increase with increasing Ca(OH)₂ content in the reaction process. A blue-shift optical spectrum of the CDs was also found with increasing Ca(OH)₂ content, which could be attributed to the increasing of the energy gaps for the CDs. The highly photoluminescent CDs obtained (quantum yield: 86%) were used to cultivate fluorescent carnations by a water culture method, while the results of fluorescence microscopy analysis indicated that the CDs had entered the plant tissue structure.

  5. NK sensitivity of neuroblastoma cells determined by a highly sensitive coupled luminescent method

    International Nuclear Information System (INIS)

    Ogbomo, Henry; Hahn, Anke; Geiler, Janina; Michaelis, Martin; Doerr, Hans Wilhelm; Cinatl, Jindrich

    2006-01-01

    The measurement of natural killer (NK) cells toxicity against tumor or virus-infected cells especially in cases with small blood samples requires highly sensitive methods. Here, a coupled luminescent method (CLM) based on glyceraldehyde-3-phosphate dehydrogenase release from injured target cells was used to evaluate the cytotoxicity of interleukin-2 activated NK cells against neuroblastoma cell lines. In contrast to most other methods, CLM does not require the pretreatment of target cells with labeling substances which could be toxic or radioactive. The effective killing of tumor cells was achieved by low effector/target ratios ranging from 0.5:1 to 4:1. CLM provides highly sensitive, safe, and fast procedure for measurement of NK cell activity with small blood samples such as those obtained from pediatric patients

  6. High resolution optically stimulated luminescence dating of a sediment core from the southwestern Sea of Okhotsk

    DEFF Research Database (Denmark)

    Sugisaki, S.; Buylaert, J. P.; Murray, A. S.

    2012-01-01

    (D-e), with stimulation by both infrared and blue light. The suitability of the measurement procedure was confirmed using dose recovery tests. A high resolution record (similar to 2 OSL ages/m) identified clear sedimentation rate changes down the core. The OSL ages are significantly dependent......Optically stimulated luminescence (OSL) dating is now widely accepted as a chronometer for terrestrial sediment. More recently, it has been suggested that OSL may also be useful in the dating of deep-sea marine sediments. In this paper, we test the usefulness of high resolution quartz OSL dating...... in application to a 19 m marine sediment core (MR0604-PC04A) taken from the southwestern Sea of Okhotsk, immediately to the north of Hokkaido, Japan. Fine-grained quartz (4 to 11 mu m) was chosen as the dosimeter, and a single-aliquot regenerative-dose protocol was used for the determination of equivalent dose...

  7. Multiple High Voltage Pulse Stressing of Polymer Thick Film Resistors

    Directory of Open Access Journals (Sweden)

    Busi Rambabu

    2014-01-01

    Full Text Available The purpose of this paper is to study high voltage interactions in polymer thick film resistors, namely, polyvinyl chloride- (PVC- graphite thick film resistors, and their applications in universal trimming of these resistors. High voltages in the form of impulses for various pulse durations and with different amplitudes have been applied to polymer thick film resistors and we observed the variation of resistance of these resistors with high voltages. It has been found that the resistance of polymer thick film resistors decreases in the case of higher resistivity materials and the resistance of polymer thick film resistor increases in the case of lower resistivity materials when high voltage impulses are applied to them. It has been also found that multiple high voltage pulse (MHVP stressing can be used to trim the polymer thick film resistors either upwards or downwards.

  8. Visible luminescence from highly textured Tb{sup 3+} doped RF sputtered zinc oxide films

    Energy Technology Data Exchange (ETDEWEB)

    Sreedharan, R. Sreeja; Krishnan, R. Reshmi; Bose, R. Jolly; Kavitha, V.S.; Suresh, S. [Department of Optoelectronics, University of Kerala, Thiruvananthapuram 695581, Kerala (India); Vinodkumar, R. [Department of Optoelectronics, University of Kerala, Thiruvananthapuram 695581, Kerala (India); Department of Physics, University College, Thiruvananthapuram, Kerala (India); Sudheer, S.K. [Department of Optoelectronics, University of Kerala, Thiruvananthapuram 695581, Kerala (India); Pillai, V.P. Mahadevan, E-mail: vpmpillai9@gmail.com [Department of Optoelectronics, University of Kerala, Thiruvananthapuram 695581, Kerala (India)

    2017-04-15

    Highly transparent, luminescent, c-axis oriented Tb{sup 3+} doped ZnO films are prepared by RF magnetron sputtering technique. The structural, morphological, optical and luminescence properties of these films are investigated as a function of Tb{sup 3+} doping concentration by X-ray diffraction (XRD), micro-Raman spectroscopy, atomic force microscopy (AFM), field emission scanning electron microscopy (FESEM), spectroscopic ellipsometry, UV-Visible spectroscopy and photoluminescence spectroscopy. The as-deposited films are found to be highly crystalline with wurtzite hexagonal phase of ZnO. The characteristic features of hexagonal wurtzite structure of ZnO, particularly the appearance of non-polar E{sub 2} modes are easily identified from the Raman spectra of the films. The surface morphology of the films revealed by FESEM and AFM images present a dense distribution of grains. The elemental analysis carried out using energy dispersive X-ray (EDX) spectra confirms the incorporation of Tb{sup 3+} ions in the ZnO lattice. The films are highly transparent in the visible region. Using ellipsometric analysis, the variation of refractive index, dielectric constant and thickness of the films are studied as a function of Tb{sup 3+} doping concentration. The photoluminescence spectra of the Tb{sup 3+} doped ZnO films recorded using an excitation radiation of wavelength 325 nm from a He-Cd laser exhibit visible luminescence ~430, 490, 516 and 542 nm. The origin of visible emissions ~490 and 542 nm in the doped films can be attributed to 5D{sub 4}→7F{sub 6} and 5D{sub 4}→7F{sub 5} transition of Tb{sup 3+} ion respectively. The intensity of the emission at 542 nm is found to be decreasing at higher doping concentration due to concentration quenching effect. The blue emission in the films can be attributed to the electron transition from shallow donor level formed by interstitial Zn atoms to the top of the valence band. The origin of the visible emission ~516 nm is attributed

  9. High temperature performance of polymer composites

    CERN Document Server

    Keller, Thomas

    2014-01-01

    The authors explain the changes in the thermophysical and thermomechanical properties of polymer composites under elevated temperatures and fire conditions. Using microscale physical and chemical concepts they allow researchers to find reliable solutions to their engineering needs on the macroscale. In a unique combination of experimental results and quantitative models, a framework is developed to realistically predict the behavior of a variety of polymer composite materials over a wide range of thermal and mechanical loads. In addition, the authors treat extreme fire scenarios up to more than 1000°C for two hours, presenting heat-protection methods to improve the fire resistance of composite materials and full-scale structural members, and discuss their performance after fire exposure. Thanks to the microscopic approach, the developed models are valid for a variety of polymer composites and structural members, making this work applicable to a wide audience, including materials scientists, polymer chemist...

  10. Luminescence and scintillation of Eu.sup.2+./sup.-doped high silica glass

    Czech Academy of Sciences Publication Activity Database

    Chewpraditkul, W.; Chen, D.; Yu, B.; Zhang, Q.; Shen, Y.; Nikl, Martin; Kučerková, Romana; Beitlerová, Alena; Wanarak, C.; Phunpueok, A.

    2011-01-01

    Roč. 5, č. 1 (2011), s. 40-42 ISSN 1862-6254 R&D Projects: GA MŠk(CZ) ME10084 Institutional research plan: CEZ:AV0Z10100521 Keywords : glasses * Eu 2+ * luminescence * scintillation * time-resolved luminescence * porous materials Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.218, year: 2011

  11. Temperature dependence of luminescence for different surface flaws in high purity silica glass

    International Nuclear Information System (INIS)

    Fournier, J.; Grua, P.; Neauport, J.; Fargin, E.; Jubera, V.; Talaga, D.; Del Guerzo, A.; Raffy, G.; Jouannigot, S.

    2013-01-01

    In situ temperature dependence of the Photoluminescence under 325 nm irradiation is used to investigate defect populations existing in different surface flaws in high purity fused silica. Five photoluminescence bands peaking at 1.9, 2.1, 2.3, 2.63 and 3.11 eV have been detected in the spectral area ranging from 1.6 up to 3.6 eV. The Gaussian deconvolution of spectra allows dividing the five luminescence bands in two categories. The former corresponds to bands showing a significant intensity enhancement while temperature decreases; the latter corresponds to bands remaining insensitive to the temperature evolution. Such a behavior brings new information on defects involved in laser damage mechanism at 351 nm in nanosecond regime. (authors)

  12. Fabrication of highly luminescent InP/Cd and InP/CdS quantum dots

    International Nuclear Information System (INIS)

    Park, Jaehyun; Kim, Sunghoon; Kim, Sungwoo; Yu, Seung Tack; Lee, Bunyeoul; Kim, Sang-Wook

    2010-01-01

    Highly luminescent InP/Cd and InP/CdS core-shell QDs were fabricated by sequential addition of cadmium acetylacetonate and dodecanethiol to InP core solutions, which showed a red-shift in absorption and emission. ICP measurement revealed the existence of cadmium and TEM images showed the increased size of InP/CdS QDs. PXRD data identified zinc blend structures of InP and InP/CdS QDs, which indexed to the (1 1 1), (2 2 0) and (3 1 1) planes. The slight shift of peaks between InP and InP/CdS QDs can demonstrate the existence of CdS shell structures.

  13. Intrinsically Microporous Polymer Membranes for High Performance Gas Separation

    KAUST Repository

    Swaidan, Raja

    2014-01-01

    This dissertation addresses the rational design of intrinsically microporous solutionprocessable polyimides and ladder polymers for highly permeable and highly selective gas transport in cornerstone applications of membrane-based gas separation

  14. Pure zinc sulfide quantum dot as highly selective luminescent probe for determination of hazardous cyanide ion

    International Nuclear Information System (INIS)

    Shamsipur, Mojtaba; Rajabi, Hamid Reza

    2014-01-01

    A rapid and simple fluorescence method is presented for selective and sensitive determination of hazardous cyanide ion in aqueous solution based on functionalized zinc sulfide (ZnS) quantum dot (QD) as luminescent prob. The ultra-small ZnS QDs were synthesized using a chemical co-precipitation method in the presence of 2-mercaptoethanol (ME) as an efficient capping agent. The prepared pure ZnS QDs was applied as an optical sensor for determination of cyanide ions in aqueous solutions. ZnS nanoparticles have exhibited a strong fluorescent emission at about 424 nm. The fluorescence intensity of QDs is linearly proportional to the cyanide ion concentration in the range 2.44 × 10 −6 to 2.59 × 10 −5 M with a detection limit of 1.70 × 10 −7 M at pH 11. The designed fluorescent sensor possesses remarkable selectivity for cyanide ion over other anions such as Cl − , Br − , F − , I − , IO 3 − , ClO 4 − , BrO 3 − , CO 3 2− , NO 2 − , NO 3 − , SO 4 2− , S 2 O 4 2− , C 2 O 4 2− , SCN − , N 3 − , citrate and tartarate with negligible influences on the cyanide detection by fluorescence spectroscopy. - Highlights: • Preparation of functionalized ZnS quantum dots in aqueous media • Highly selective quantum dot based luminescent probe for determination of cyanide • Fast and sensitive determination of hazardous CN − by fluorescence quenching

  15. Pure zinc sulfide quantum dot as highly selective luminescent probe for determination of hazardous cyanide ion

    Energy Technology Data Exchange (ETDEWEB)

    Shamsipur, Mojtaba, E-mail: mshamsipur@yahoo.com [Department of Chemistry, Razi University, Kermanshah (Iran, Islamic Republic of); Rajabi, Hamid Reza, E-mail: h.rajabi@mail.yu.ac.ir [Chemistry Department, Yasouj University, Yasouj 75918-74831 (Iran, Islamic Republic of)

    2014-03-01

    A rapid and simple fluorescence method is presented for selective and sensitive determination of hazardous cyanide ion in aqueous solution based on functionalized zinc sulfide (ZnS) quantum dot (QD) as luminescent prob. The ultra-small ZnS QDs were synthesized using a chemical co-precipitation method in the presence of 2-mercaptoethanol (ME) as an efficient capping agent. The prepared pure ZnS QDs was applied as an optical sensor for determination of cyanide ions in aqueous solutions. ZnS nanoparticles have exhibited a strong fluorescent emission at about 424 nm. The fluorescence intensity of QDs is linearly proportional to the cyanide ion concentration in the range 2.44 × 10{sup −6} to 2.59 × 10{sup −5} M with a detection limit of 1.70 × 10{sup −7} M at pH 11. The designed fluorescent sensor possesses remarkable selectivity for cyanide ion over other anions such as Cl{sup −}, Br{sup −}, F{sup −}, I{sup −}, IO{sub 3}{sup −}, ClO{sub 4}{sup −}, BrO{sub 3}{sup −}, CO{sub 3}{sup 2−}, NO{sub 2}{sup −}, NO{sub 3}{sup −}, SO{sub 4}{sup 2−}, S{sub 2}O{sub 4}{sup 2−}, C{sub 2}O{sub 4}{sup 2−}, SCN{sup −}, N{sub 3}{sup −}, citrate and tartarate with negligible influences on the cyanide detection by fluorescence spectroscopy. - Highlights: • Preparation of functionalized ZnS quantum dots in aqueous media • Highly selective quantum dot based luminescent probe for determination of cyanide • Fast and sensitive determination of hazardous CN{sup −} by fluorescence quenching.

  16. An alkaline one-pot reaction to synthesize luminescent Eu-BTC MOF nanorods, highly pure and water-insoluble, under room conditions

    Energy Technology Data Exchange (ETDEWEB)

    Medina-Velazquez, D. Y., E-mail: dyolotzin@correo.azc.uam.mx; Alejandre-Zuniga, B. Y.; Loera-Serna, S.; Ortiz, E. M. [Universidad Autónoma Metropolitana-Azcapotzalco, División de Ciencias Básicas e Ingeniería (Mexico); Morales-Ramirez, A. de J. [CIITEC IPN, Instituto Politécnico Nacional (Mexico); Garfias-Garcia, E. [Universidad Autónoma Metropolitana-Azcapotzalco, División de Ciencias Básicas e Ingeniería (Mexico); Garcia-Murillo, A. [CIITEC IPN, Instituto Politécnico Nacional (Mexico); Falcony, C. [Centro de Investigación y Estudios Avanzados, Departamento de Física (Mexico)

    2016-12-15

    The increasing demand for optoelectronic devices requires the development of luminescent materials with high luminescence efficiency and low energy demands, and the metalorganic frameworks (MOFs) with lanthanides ions offer great potential in this area. The metalorganic materials provide properties of flexibility, low density, low-cost methods of synthesis, and insolubility in water, which gives them an advantage over traditional phosphors. In this study, a benzenetricarboxylate ligand (BTC) with a Eu{sup 3+} MOF was synthesized, and its structural and luminescent properties were measured. The metalorganic compound was generated in a one-pot reaction from europium nitrate and trimesic acid precursors. Through characterization by X-ray diffraction powder, infrared spectroscopy, SEM structural characterization, and luminescent spectroscopy, the formation of Europium benzenetricarboxylate (Eu-BTC) MOF nanorods was tested and the calculated value was in the range of 30–60 nm. A red luminescent emission with high intensity was observed for all the procedures.

  17. Highly sensitive luminescent sensor for cyanide ion detection in aqueous solution based on PEG-coated ZnS nanoparticles.

    Science.gov (United States)

    Mehta, Surinder K; Salaria, Khushboo; Umar, Ahmad

    2013-03-15

    Using polyethylene glycol (PEG) coated ZnS nanoparticles (NPs), a novel and highly sensitive luminescent sensor for cyanide ion detection in aqueous solution has been presented. ZnS NPs have been used to develop efficient luminescence sensor which exhibits high reproducibility and stability with the lowest limit of detection of 1.29×10(-6) mol L(-1). The observed limit of detection of the fabricated sensor is ~6 times lower than maximum value of cyanide permitted by United States Environmental Protection Agency for drinking water (7.69×10(-6) mol L(-1)). The interfering studies show that the developed sensor possesses good selectivity for cyanide ion even in presence of other coexisting ions. Importantly, to the best of our knowledge, this is the first report which demonstrates the utilization of PEG- coated ZnS NPs for efficient luminescence sensor for cyanide ion detection in aqueous solution. This work demonstrates that rapidly synthesized ZnS NPs can be used to fabricate efficient luminescence sensor for cyanide ion detection. Copyright © 2013 Elsevier B.V. All rights reserved.

  18. Syntheses, structures and luminescence for zinc coordination polymers based on a multifunctional 4′-(3-carboxyphenyl)- 3,2′:6′,3″-terpyridine ligand

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Yue; Yang, Meng-Lin; Hu, Huai-Ming, E-mail: ChemHu1@NWU.EDU.CN; Xu, Bing; Wang, Xiaofang; Xue, Ganglin

    2016-07-15

    Six new coordination polymers, [ZnLCl]{sub n}(1), [ZnL{sub 2}]{sub n}·2nH{sub 2}O (2), [Zn{sub 2}L(o-bdc)(OH)]{sub n}·0.5nH{sub 2}O (3), [Zn{sub 2}L(m-bdc)(OH)]{sub n}·nH{sub 2}O (4), [Zn{sub 2}L{sub 2}(p-bdc) (H{sub 2}O){sub 2}]{sub n}·nH{sub 2}O (5), [Zn{sub 2}L(1,2,4-btc)(H{sub 2}O)]{sub n}(6), (HL=4′-(3-carboxyphenyl)- 3,2′:6′,3″-terpyridine, H{sub 2}(o-bdc)= benzene-1,2-dicarboxylic acid, H{sub 2}(m-bdc)= benzene-1,3-dicarboxylic acid, H{sub 2}(p-bdc)= benzene-1,4-dicarboxylic acid, H{sub 3}(1,2,4-btc)= benzene-1,2,4-tricarboxylic acid) have been synthesized under the hydrothermal conditions. Compound 1 displays a 3-connected 2D network structure with point symbol of {8"2.10}. Compound 2 exhibits 1D infinite loop chain structure. Compound 3 possesses a (3,8)-connected 3D framework composed of tetranuclear units with point symbol of {4"3}{sub 2}{4"6.6"1"8.8"4}. Compound 4 features a typical 2D hcb network based on tetranuclear zinc(II) units with point symbol of {4"4.6"2}. Compound 5 presents a classical two-fold penetration sql network with point symbol of {6"3}. Compound 6 can be seen as a (3,3,6)-connected 3D net with point symbol of {4"2.6"4.8"9}{4"2.6}{6"3}. The thermal stability and luminescent properties of compounds 1–6 in the solid state are discussed in detail. - Graphical abstract: Six new Zn(II) coordination polymers based on multicarboxylate and terpyridyl derivative ligands have synthesized under the hydrothermal conditions and the thermal stability and luminescence are discussed. Display Omitted.

  19. Novel synthesis of Eu-doped SiAlON luminescent materials from a preceramic polymer and nano-sized fillers

    Directory of Open Access Journals (Sweden)

    E. Bernardo

    2014-06-01

    The reduction of Eu3+ into Eu2+ incorporated in SiAlON was favored by the presence of carbon derived from the pyrolysis of the preceramic polymers. The nanometric distribution of filler materials and the high yield of the selected preceramic polymers in terms of Si and N atoms led to the formation of the desired phases at relatively low firing temperatures (e.g. 3 h at 1550–1600 °C in pure nitrogen.

  20. Preparing high-density polymer brushes by mechanically assisted polymer assembly (MAPA)

    Science.gov (United States)

    Wu, Tao; Efimenko, Kirill; Genzer, Jan

    2001-03-01

    We introduce a novel method of modifying the surface properties of materials. This technique, called MAPA (="mechanically assisted polymer assembly"), is based on: 1) chemically attaching polymerization initiators to the surface of an elastomeric network that has been previously stretched by a certain length, Δx, and 2) growing end-anchored macromolecules using surface initiated ("grafting from") atom transfer living radical polymerization. After the polymerization, the strain is removed from the substrate, which returns to its original size causing the grafted macromolecules to stretch away from the substrate and form a dense polymer brush. We demonstrate the feasibility of the MAPA method by preparing high-density polymer brushes of poly(acryl amide), PAAm. We show that, as expected, the grafting density of the PAAm brushes can be increased by increasing Δx. We demonstrate that polymer brushes with extremely high grafting densities can be successfully prepared by MAPA.

  1. Evolution of sequence-defined highly functionalized nucleic acid polymers

    Science.gov (United States)

    Chen, Zhen; Lichtor, Phillip A.; Berliner, Adrian P.; Chen, Jonathan C.; Liu, David R.

    2018-03-01

    The evolution of sequence-defined synthetic polymers made of building blocks beyond those compatible with polymerase enzymes or the ribosome has the potential to generate new classes of receptors, catalysts and materials. Here we describe a ligase-mediated DNA-templated polymerization and in vitro selection system to evolve highly functionalized nucleic acid polymers (HFNAPs) made from 32 building blocks that contain eight chemically diverse side chains on a DNA backbone. Through iterated cycles of polymer translation, selection and reverse translation, we discovered HFNAPs that bind proprotein convertase subtilisin/kexin type 9 (PCSK9) and interleukin-6, two protein targets implicated in human diseases. Mutation and reselection of an active PCSK9-binding polymer yielded evolved polymers with high affinity (KD = 3 nM). This evolved polymer potently inhibited the binding between PCSK9 and the low-density lipoprotein receptor. Structure-activity relationship studies revealed that specific side chains at defined positions in the polymers are required for binding to their respective targets. Our findings expand the chemical space of evolvable polymers to include densely functionalized nucleic acids with diverse, researcher-defined chemical repertoires.

  2. Exploring the origin of high optical absorption in conjugated polymers

    KAUST Repository

    Vezie, Michelle S.

    2016-05-16

    The specific optical absorption of an organic semiconductor is critical to the performance of organic optoelectronic devices. For example, higher light-harvesting efficiency can lead to higher photocurrent in solar cells that are limited by sub-optimal electrical transport. Here, we compare over 40 conjugated polymers, and find that many different chemical structures share an apparent maximum in their extinction coefficients. However, a diketopyrrolopyrrole-thienothiophene copolymer shows remarkably high optical absorption at relatively low photon energies. By investigating its backbone structure and conformation with measurements and quantum chemical calculations, we find that the high optical absorption can be explained by the high persistence length of the polymer. Accordingly, we demonstrate high absorption in other polymers with high theoretical persistence length. Visible light harvesting may be enhanced in other conjugated polymers through judicious design of the structure.

  3. Exploring the origin of high optical absorption in conjugated polymers

    KAUST Repository

    Vezie, Michelle S.; Few, Sheridan; Meager, Iain; Pieridou, Galatia; Dö rling, Bernhard; Ashraf, Raja Shahid; Goñ i, Alejandro R.; Bronstein, Hugo; McCulloch, Iain; Hayes, Sophia C.; Campoy-Quiles, Mariano; Nelson, Jenny

    2016-01-01

    The specific optical absorption of an organic semiconductor is critical to the performance of organic optoelectronic devices. For example, higher light-harvesting efficiency can lead to higher photocurrent in solar cells that are limited by sub-optimal electrical transport. Here, we compare over 40 conjugated polymers, and find that many different chemical structures share an apparent maximum in their extinction coefficients. However, a diketopyrrolopyrrole-thienothiophene copolymer shows remarkably high optical absorption at relatively low photon energies. By investigating its backbone structure and conformation with measurements and quantum chemical calculations, we find that the high optical absorption can be explained by the high persistence length of the polymer. Accordingly, we demonstrate high absorption in other polymers with high theoretical persistence length. Visible light harvesting may be enhanced in other conjugated polymers through judicious design of the structure.

  4. Luminescence nanothermometry

    Science.gov (United States)

    Jaque, Daniel; Vetrone, Fiorenzo

    2012-07-01

    The current status of luminescence nanothermometry is reviewed in detail. Based on the main parameters of luminescence including intensity, bandwidth, bandshape, polarization, spectral shift and lifetime, we initially describe and compare the different classes of luminescence nanothermometry. Subsequently, the various luminescent materials used in each case are discussed and the mechanisms at the root of the luminescence thermal sensitivity are described. The most important results obtained in each case are summarized and the advantages and disadvantages of these approaches are discussed.The current status of luminescence nanothermometry is reviewed in detail. Based on the main parameters of luminescence including intensity, bandwidth, bandshape, polarization, spectral shift and lifetime, we initially describe and compare the different classes of luminescence nanothermometry. Subsequently, the various luminescent materials used in each case are discussed and the mechanisms at the root of the luminescence thermal sensitivity are described. The most important results obtained in each case are summarized and the advantages and disadvantages of these approaches are discussed. This work was supported by the Universidad Autónoma de Madrid and Comunidad Autónoma de Madrid (Project S2009/MAT-1756), by the Spanish Ministerio de Educacion y Ciencia (MAT2010-16161) and by Caja Madrid Foundation.

  5. Crystal and molecular simulation of high-performance polymers.

    Science.gov (United States)

    Colquhoun, H M; Williams, D J

    2000-03-01

    Single-crystal X-ray analyses of oligomeric models for high-performance aromatic polymers, interfaced to computer-based molecular modeling and diffraction simulation, have enabled the determination of a range of previously unknown polymer crystal structures from X-ray powder data. Materials which have been successfully analyzed using this approach include aromatic polyesters, polyetherketones, polythioetherketones, polyphenylenes, and polycarboranes. Pure macrocyclic homologues of noncrystalline polyethersulfones afford high-quality single crystals-even at very large ring sizes-and have provided the first examples of a "protein crystallographic" approach to the structures of conventionally amorphous synthetic polymers.

  6. High Molecular Weight Polymers in the New Chemicals Program

    Science.gov (United States)

    There are three categories or types of High Molecular Weight (HMW, 10,000 daltons) polymers typically reviewed by the New Chemicals Program: Soluble, insoluble, and water absorbing. Each of the three types are treated differently.

  7. Two three-dimensional coordination polymers of lead(II) with iminodiacetate and naphthalene-dicarboxylate anions: Synthesis, characterization and luminescence behavior

    Energy Technology Data Exchange (ETDEWEB)

    Hazari, Debdoot; Jana, Swapan Kumar [Department of Chemistry and Chemical Technology, Vidyasagar University, Midnapore 721 102, West Bengal (India); Fleck, Michel [Institute of Mineralogy and Crystallography, University of Vienna, Geozentrum, Althanstr. 9, A-1090 Vienna (Austria); Zangrando, Ennio [Department of Chemical and Pharmaceutical Sciences, University of Trieste, 34127 Trieste (Italy); Dalai, Sudipta, E-mail: sudipta@mail.vidyasagar.ac.in [Department of Chemistry and Chemical Technology, Vidyasagar University, Midnapore 721 102, West Bengal (India)

    2014-11-15

    Two lead(II) compounds [Pb{sub 3}(idiac){sub 3}(phen){sub 2}(H{sub 2}O)]·2(H{sub 2}O) (1) and [Pb(ndc)]{sub n} (2), where H{sub 2}idiac=iminodiacetic acid, phen=1,10-phenanthroline and H{sub 2}ndc=naphthalene-2,6-dicarboxylic acid, have been synthesized and structurally characterized. Single crystal X-ray diffraction analysis showed that compound 1 is a discrete trinuclear complex (of two-fold symmetry) which evolves to a supramolecular 3D network via π–π interactions, while in compound 2 the naphthalene dicarboxylate anion act as a linker to form a three dimensional architecture, where the anion adopts a bis-(bidentate bridging) coordination mode connecting four Pb(II) centers. The photoluminescence property of the two complexes has been studied. - graphical abstract: Two new topologically different 1D coordination polymers formed by Pb{sub 4} clusters have been synthesized and characterized by x-ray analysis. The luminescence and thermal properties have been studied. - Highlights: • 1 is a trinuclear complex of Pb(II) growing to 3D network via weak interactions. • In 1, layers of (4,4) rhomboidal topology are identified. • In 2, the ndc anion adopts interesting bis-(bidentate bridging) coordination. • In 2, network is reinforced by C–H…π-ring interactions between the ndc rings.

  8. Synthesis, Crystal Structure and Luminescent Property of A Novel Cd(II) Coordination Polymer with Bis-imidazole Ligand

    International Nuclear Information System (INIS)

    Zhou, Yong Hong

    2013-01-01

    The key to the successful design of metal-organic coordination polymers is the judicious selection of organic ligand. Recently, polydentate aromatic nitrogen heterocyclic ligands with five-membered rings have been well-studied in the construction of supramolecular structure for their N-coordinated sites apt to coordinating to transition metals. Similar to six-membered N-heterocyclic ligands, the azole-based five-membered N-heterocyclic ligands, such as imidazoles, triazoles and tetrazoles have been extensively employed in the construction of various coordination polymers with diverse topologies and interesting properties. The bis(azole) ligands in which N-donor azole rings (imidazole, triazole, or tetrazole) are separated by alkyl, (CH 2 ) n , spacers are good choices for flexible bridging ligands. The conformational flexibility of the spacers makes the ligands adaptable to various coordination networks with one-, two-, and three dimensional structures

  9. Photoinduced proton transfer coupled with energy transfer: Mechanism of sensitized luminescence of terbium ion by salicylic acid doped in polymer.

    Science.gov (United States)

    Misra, Vinita; Mishra, Hirdyesh

    2008-06-28

    In the present work, excited state intramolecular proton transfer (ESIPT) in salicylic acid (SA) monoanion and subsequent sensitization of Tb(3+) ion in polyvinyl alcohol (PVA) have been studied. The study has been carried out both by steady state and time domain fluorescence measurement techniques at room temperature. It is found that the SA completely ionizes and exists as monoanion in PVA. It exhibits a large Stokes shifted blue emission (10 000 cm(-1)) due to ESIPT and shows a decay time of 6.85 ns. On the other hand, Tb(3+) ion shows a very weak green emission and a decay time of approximately 641 mus in PVA film. Upon incorporating Tb(3+) ion in SA doped PVA film, both intensity and decay time of SA decrease and sensitized emission from Tb(+3) ion along with 3.8 mus rise time is observed. Energy transfer is found to take place both from excited singlet as well as triplet states. A brief description of the properties of the present system from the viewpoint of luminescent solar collector material is addressed.

  10. Synthesis of highly luminescent Mn:ZnSe/ZnS nanocrystals in aqueous media

    International Nuclear Information System (INIS)

    Fang Zheng; Wu Ping; Zhong Xinhua; Yang Yongji

    2010-01-01

    High-quality water-dispersible Mn 2+ -doped ZnSe core/ZnS shell (Mn:ZnSe/ZnS) nanocrystals have been synthesized directly in aqueous media. Overcoating a high bandgap ZnS shell around the Mn:ZnSe cores can bring forward an efficient energy transfer from the ZnSe host nanocrystals to the dopant Mn. The quantum yields of the dopant Mn photoluminescence in the as-prepared water-soluble Mn:ZnSe/ZnS core/shell nanocrystals can be up to 35 ± 5%. The optical features and structure of the obtained Mn:ZnSe/ZnS core/shell nanocrystals have been characterized by UV-vis, PL spectroscopy, TEM, XRD and ICP elementary analysis. The influences of various experimental variables, including the Mn concentration, the Se/Zn molar ratio as well as the kind and amount of capping ligand used in the core production and shell deposition process, on the luminescent properties of the obtained Mn:ZnSe/ZnS nanocrystals have been systematically investigated.

  11. Luminescent GdVO{sub 4}:Sm{sup 3+} quantum dots enhance power conversion efficiency of bulk heterojunction polymer solar cells by Förster resonance energy transfer

    Energy Technology Data Exchange (ETDEWEB)

    Bishnoi, Swati [CSIR-Network of Institutes for Solar Energy, New Delhi 110001 (India); Luminescent Materials and Devices Group, CSIR-National Physical Laboratory, New Delhi 110012 (India); Academy of Scientific and Innovative Research (AcSIR), CSIR-National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi 110012 (India); Gupta, Vinay, E-mail: drvinaygupta@netscape.net; Sharma, Gauri D.; Chand, Suresh [CSIR-Network of Institutes for Solar Energy, New Delhi 110001 (India); Organic and Hybrid Solar Cells Group, Physics of Energy Harvesting Division, CSIR-National Physical Laboratory, New Delhi 110012 (India); Sharma, Chhavi; Kumar, Mahesh [Ultrafast Optoelectronics and Terahertz Photonics Lab, Physics of Energy Harvesting Division, CSIR-National Physical Laboratory, New Delhi 110012 (India); Haranath, D. [CSIR-Network of Institutes for Solar Energy, New Delhi 110001 (India); Luminescent Materials and Devices Group, CSIR-National Physical Laboratory, New Delhi 110012 (India); Naqvi, Sheerin [Luminescent Materials and Devices Group, CSIR-National Physical Laboratory, New Delhi 110012 (India)

    2016-07-11

    In this work, we report enhanced power conversion efficiency (PCE) of bulk heterojunction polymer solar cells by Förster resonance energy transfer (FRET) from samarium-doped luminescent gadolinium orthovanadate (GdVO{sub 4}:Sm{sup 3+}) quantum dots (QDs) to polythieno[3,4-b]-thiophene-co-benzodithiophene (PTB7) polymer. The photoluminescence emission spectrum of GdVO{sub 4}:Sm{sup 3+} QDs overlaps with the absorption spectrum of PTB7, leading to FRET from GdVO{sub 4}:Sm{sup 3+} to PTB7, and significant enhancements in the charge-carrier density of excited and polaronic states of PTB7 are observed. This was confirmed by means of femtosecond transient absorption spectroscopy. The FRET from GdVO{sub 4}:Sm{sup 3+} QDs to PTB7 led to a remarkable increase in the power conversion efficiency (PCE) of PTB7:GdVO{sub 4}:Sm{sup 3+}:PC{sub 71}BM ([6,6]-phenyl-C{sub 71}-butyric acid methyl ester) polymer solar cells. The PCE in optimized ternary blend PTB7:GdVO{sub 4}:Sm{sup 3+}:PC{sub 71}BM (1:0.1:1.5) is increased to 8.8% from 7.2% in PTB7:PC{sub 71}BM. This work demonstrates the potential of rare-earth based luminescent QDs in enhancing the PCE of polymer solar cells.

  12. Synthesis and luminescent properties of a novel green-emitting Tb (Ⅲ) complex based on amino-modified fluorine silicone oil and isophorone diisocyanate

    Science.gov (United States)

    Hao, Haixia; Chu, Yang; Yu, Zhenjiang; Xie, Hongde; Seo, Hyo Jin

    2017-10-01

    The novel luminescent polymer-rare earth complexes, denoted as (PFSi-IPDI)-Tb(Ⅲ)-Phen, have been successfully synthesized and can be made into flexible films. Amino-modified fluorine silicone oil-isophorone diisocyanate (PFSi-IPDI) was used as the host macromolecular ligand, and 1, 10-Phenanthroline (Phen) as the secondary small-molecular co-ligand. The luminescent lanthanide complexes were characterized by fourier transform infrared (FITR), scanning electron microscope (SEM), thermogravimetric analysis (TGA). The luminescent properties were investigated through photoluminescence excitation (PLE) and emission (PL) spectroscopy. FTIR analysis verifies the successful preparation and integration of PFSi-IPDI to Tb3+. The comparatively uniform morphological structure can be observed in the images of SEM. The polymer-rare earth complexes display the typical luminescence emission peaks under the excitation wavelength of 330 nm. From the decay curve, the short lifetime (about 0.89 ms) is observed for (PFSi-IPDI)-Tb(Ⅲ)-Phen (0.6 mol/L). Moreover, these luminescent polymer-rare earth complexes possess superior thermal stability (T5 > 195 °C). All the interesting results suggest the potential application of the luminescent polymer-rare earth complexes in green-emitting luminescent materials under high temperature.

  13. Pure zero-dimensional Cs4PbBr6 single crystal rhombohedral microdisks with high luminescence and stability.

    Science.gov (United States)

    Zhang, Haihua; Liao, Qing; Wu, Yishi; Chen, Jianwei; Gao, Qinggang; Fu, Hongbing

    2017-11-08

    Zero-dimensional (0D) perovskite Cs 4 PbBr 6 has been speculated to be an efficient solid-state emitter, exhibiting strong luminescense on achieving quantum confinement. Although several groups have reported strong green luminescence from Cs 4 PbBr 6 powders and nanocrystals, doubts that the origin of luminescence comes from Cs 4 PbBr 6 itself or CsPbBr 3 impurities have been a point of controversy in recent investigations. Herein, we developed a facile one-step solution self-assembly method to synthesize pure zero-dimensional rhombohedral Cs 4 PbBr 6 micro-disks (MDs) with a high PLQY of 52% ± 5% and photoluminescence full-width at half maximum (FWHM) of 16.8 nm. The obtained rhombohedral MDs were high quality single-crystalline as demonstrated by XRD and SAED patterns. We demonstrated that Cs 4 PbBr 6 MDs and CsPbBr 3 MDs were phase-separated from each other and the strong green emission comes from Cs 4 PbBr 6 . Power and temperature dependence spectra evidenced that the observed strong green luminescence of pure Cs 4 PbBr 6 MDs originated from direct exciton recombination in the isolated octahedra with a large binding energy of 303.9 meV. Significantly, isolated PbBr 6 4- octahedra separated by a Cs + ion insert in the crystal lattice is beneficial to maintaining the structural stability, depicting superior thermal and anion exchange stability. Our study provides an efficient approach to obtain high quality single-crystalline Cs 4 PbBr 6 MDs with highly efficient luminescence and stability for further optoelectronic applications.

  14. High-pressure luminescence spectroscopy of EuAl2O4 phosphor

    International Nuclear Information System (INIS)

    Zorenko, Yu.; Gorbenko, V.; Grinberg, M.; Turos-Matysiak, R.; Kuklinski, B.

    2007-01-01

    EuAl 2 O 4 powder phosphor was prepared by solid-state reaction of EuO and Al 2 O 3 oxides in vacuum. The influence of conditions of preparation on spectral lineshape of Eu 2+ emission was analyzed. It was found that the fluorescence spectra of vacuum-prepared EuAl 2 O 4 samples at 300 K present the superposition of three bands peaked at 430, 500 and 528 nm, corresponding to the 4f 6 5d 1 →4f 7 ( 8 S 7/2 ) transition of Eu 2+ ions in the different sites of EuAl 2 O 4 lattice. The luminescence of Eu 2+ centers in EuAl 2 O 4 host was also studied using the high-pressure spectroscopy up to 67 kbar. It was found that the bright green-yellow fluorescence of EuAl 2 O 4 at 300 K in the band peaked at 520-530nm range can be presented by superposition of two Gaussian sub-bands. The different pressure shifts -23 and -27cm -1 /kbar for two sub-bands were found. Such a structure of the emission spectrum was attributed to the existence of two different Eu 2+ centers in the Eu II 2+ sites of EuAl 2 O 4 lattice with higher coordination number

  15. Highly efficient luminescent solar concentrators based on earth-abundant indirect-bandgap silicon quantum dots

    Science.gov (United States)

    Meinardi, Francesco; Ehrenberg, Samantha; Dhamo, Lorena; Carulli, Francesco; Mauri, Michele; Bruni, Francesco; Simonutti, Roberto; Kortshagen, Uwe; Brovelli, Sergio

    2017-02-01

    Building-integrated photovoltaics is gaining consensus as a renewable energy technology for producing electricity at the point of use. Luminescent solar concentrators (LSCs) could extend architectural integration to the urban environment by realizing electrode-less photovoltaic windows. Crucial for large-area LSCs is the suppression of reabsorption losses, which requires emitters with negligible overlap between their absorption and emission spectra. Here, we demonstrate the use of indirect-bandgap semiconductor nanostructures such as highly emissive silicon quantum dots. Silicon is non-toxic, low-cost and ultra-earth-abundant, which avoids the limitations to the industrial scaling of quantum dots composed of low-abundance elements. Suppressed reabsorption and scattering losses lead to nearly ideal LSCs with an optical efficiency of η = 2.85%, matching state-of-the-art semi-transparent LSCs. Monte Carlo simulations indicate that optimized silicon quantum dot LSCs have a clear path to η > 5% for 1 m2 devices. We are finally able to realize flexible LSCs with performances comparable to those of flat concentrators, which opens the way to a new design freedom for building-integrated photovoltaics elements.

  16. Luminescence and luminescence quenching of highly efficient Y2Mo4O15:Eu3+ phosphors and ceramics

    OpenAIRE

    Janulevičius, Matas; Marmokas, Paulius; Misevičius, Martynas; Grigorjevaitė, Julija; Mikoliūnaitė, Lina; Šakirzanovas, Simas; Katelnikovas, Artūras

    2016-01-01

    A good LED phosphor must possess strong enough absorption, high quantum yields, colour purity, and quenching temperatures. Our synthesized Y2Mo4O15:Eu3+ phosphors possess all of these properties. Excitation of these materials with near-UV or blue radiation yields bright red emission and the colour coordinates are relatively stable upon temperature increase. Furthermore, samples doped with 50% Eu3+ showed quantum yields up to 85%, what is suitable for commercial application. Temperature depend...

  17. High-performance polymer photovoltaic cells and photodetectors

    Science.gov (United States)

    Yu, Gang; Srdanov, Gordana; Wang, Hailiang; Cao, Yong; Heeger, Alan J.

    2001-02-01

    Polymer photovoltaic cells and photodetectors have passed their infancy and become mature technologies. The energy conversion efficiency of polymer photovoltaic cells have been improved to over 4.1% (500 nm, 10 mW/cm2). Such high efficiency polymer photovoltaic cells are promising for many applications including e-papers, e-books and smart- windows. The development of polymer photodetectors is even faster. The performance parameters have been improved to the level meeting all specifications for practical applications. The polymer photodetectors are of high photosensitivity (approximately 0.2 - 0.3 A/Watt in visible and UV), low dark current (0.1 - 1 nA/cm2), large dynamic range (> 8 orders of magnitude), linear intensity dependence, low noise level and fast response time (to nanosecond time domain). These devices show long shelf and operation lives. The advantages of low manufacturing cost, large detection area, and easy hybridization and integration with other electronic or optical components make the polymer photodetectors promising for a variety of applications including chemical/biomedical analysis, full-color digital image sensing and high energy radiation detection.

  18. Highly visible-light luminescence properties of the carboxyl-functionalized short and ultrashort MWNTs

    International Nuclear Information System (INIS)

    Luo Yongsong; Xia Xiaohong; Liang Ying; Zhang Yonggang; Ren Qinfeng; Li Jialin; Jia Zhijie; Tang Yiwen

    2007-01-01

    Luminescence of the short multiwalled carbon nanotubes (MWNTs) conjugated with carboxylic acid groups has been studied. The results show that the carboxyl-functionalized short MWNTs could emit luminescence and the emission peak appears at 500 nm with a corresponding optimal excitation wavelength centering at 310 nm. When the short MWNTs are filtered through 0.15 μm polytetrafluoroethylene (PTFE) membrane, the ultrashort MWNTs are obtained from the filtrate. An interesting feature for the ultrashort MWNTs is that the emission intensity is strengthened and the peak is slightly blue shifted to 460 nm. This result indicates that the luminescence properties of MWNTs are strongly affected by the tube length. After chemical oxidization cutting, defects and carboxylic acid groups at the tube end and/or sidewall can be produced; the more shorten of MWNTs, the better dispersion and carboxylic passivation of the nanotubes, and the more intense luminescence emissions. The broad emissions are logically attributed to the trapping of excitation energy by defect sites in the carboxyl-functionalized nanotube structure. - Graphical abstract: Luminescence of the short and ultrashort multiwalled carbon nanotubes (MWNTs) conjugated with carboxylic acid groups, which is logically attributed to the trapping of excitation energy by defect sites, has been studied

  19. Hydrothermal synthesis of highly luminescent blue-emitting ZnSe(S) quantum dots exhibiting low toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Mirnajafizadeh, Fatemeh; Ramsey, Deborah; McAlpine, Shelli [School of Chemistry, University of New South Wales, Sydney, NSW 2052 (Australia); Wang, Fan; Reece, Peter [School of Physics, University of New South Wales, Sydney, NSW 2052 (Australia); Stride, John Arron, E-mail: j.stride@unsw.edu.au [School of Chemistry, University of New South Wales, Sydney, NSW 2052 (Australia); Bragg Institute, Australian Nuclear Science and Technology Organisation, PMB 1, Menai, NSW 2234 (Australia)

    2016-07-01

    Highly luminescent quantum dots (QDs) that emit in the visible spectrum are of interest to a number of imaging technologies, not least that of biological samples. One issue that hinders the application of luminescent markers in biology is the potential toxicity of the fluorophore. Here we show that hydrothermally synthesized ZnSe(S) QDs have low cytotoxicity to both human colorectal carcinoma cells (HCT-116) and human skin fibroblast cells (WS1). The QDs exhibited a high degree of crystallinity, with a strong blue photoluminescence at up to 29% quantum yield relative to 4′,6-diamidino-2-phenylindole (DAPI) without post-synthetic UV-irradiation. Confocal microscopy images obtained of HCT-116 cells after incubation with the QDs highlighted the stability of the particles in cell media. Cytotoxicity studies showed that both HCT-116 and WS1 cells retain 100% viability after treatment with the QDs at concentrations up to 0.5 g/L, which makes them of potential use in biological imaging applications. - Highlights: • Highly luminescent ZnSe(S) QDs were synthesized using a simple, one-step hydrothermal method. • The as-synthesized QDs were found to be nontoxic in the presence of biological cells. • The QDs were stable in biological media with identical emission profile to that in water.

  20. Properties of Polymer Composites Used in High-Voltage Applications

    Directory of Open Access Journals (Sweden)

    Ilona Pleşa

    2016-04-01

    Full Text Available The present review article represents a comprehensive study on polymer micro/nanocomposites that are used in high-voltage applications. Particular focus is on the structure-property relationship of composite materials used in power engineering, by exploiting fundamental theory as well as numerical/analytical models and the influence of material design on electrical, mechanical and thermal properties. In addition to describing the scientific development of micro/nanocomposites electrical features desired in power engineering, the study is mainly focused on the electrical properties of insulating materials, particularly cross-linked polyethylene (XLPE and epoxy resins, unfilled and filled with different types of filler. Polymer micro/nanocomposites based on XLPE and epoxy resins are usually used as insulating systems for high-voltage applications, such as: cables, generators, motors, cast resin dry-type transformers, etc. Furthermore, this paper includes ample discussions regarding the advantages and disadvantages resulting in the electrical, mechanical and thermal properties by the addition of micro- and nanofillers into the base polymer. The study goals are to determine the impact of filler size, type and distribution of the particles into the polymer matrix on the electrical, mechanical and thermal properties of the polymer micro/nanocomposites compared to the neat polymer and traditionally materials used as insulation systems in high-voltage engineering. Properties such as electrical conductivity, relative permittivity, dielectric losses, partial discharges, erosion resistance, space charge behavior, electric breakdown, tracking and electrical tree resistance, thermal conductivity, tensile strength and modulus, elongation at break of micro- and nanocomposites based on epoxy resin and XLPE are analyzed. Finally, it was concluded that the use of polymer micro/nanocomposites in electrical engineering is very promising and further research work

  1. Luminescence dating

    International Nuclear Information System (INIS)

    Rieser, U.

    2009-01-01

    The luminescence techniques have evolved over the last 40 years to a powerful dating instrument in archaeology and geoscience. Depending on how the luminescence is stimulated, one distinguishes the phenomena of thermoluminescence (TL), optically stimulated luminescence (OSL) and infrared stimulated luminescence (IRSL). Each of these phenomena has its specific potential for dating various archaeological materals in the time range from medieval back to palaeolithic periods, or, speaking in geological terms, for dating of Holocene and late Pleistocene objects. The OSL and IRSL techniques are sometimes treated together as 'optical dating'. The luminescence techniques differ from other major dating techniques, such as 14 C, essentially by their applicability to inorganic materials, their wide age-range from about 100 years to more than 100,000 years and the kind of datable events which are the last exposure to heat or to light. (author). 10 refs., 3 figs.

  2. Luminescence dating

    International Nuclear Information System (INIS)

    Rieser, U.

    2008-01-01

    The luminescence techniques have evolved over the last 40 years to a powerful dating instrument in archaeology and geoscience. Depending on how the luminescence is stimulated, one distinguishes the phenomena of thermoluminescence (TL), optically stimulated luminescence (OSL) and infrared stimulated luminescence (IRSL). Each of these phenomena has its specific potential for dating various archaeological materals in the time range from medieval back to palaeolithic periods, or, speaking in geological terms, for dating of Holocene and late Pleistocene objects. The OSL and IRSL techniques are sometimes treated together as 'optical dating'. The luminescence techniques differ from other major dating techniques, such as 14 C, essentially by their applicability to inorganic materials, their wide age-range from about 100 years to more than 100,000 years and the kind of datable events which are the last exposure to heat or to light. (author). 10 refs., 3 figs

  3. Luminescence dating

    International Nuclear Information System (INIS)

    Rieser, U.

    2012-01-01

    The luminescence techniques have evolved over the last 40 years to a powerful dating instrument in archaeology and geoscience. Depending on how the luminescence is stimulated, one distinguishes the phenomena of thermoluminescence (TL), optically stimulated luminescence (OSL) and infrared stimulated luminescence (IRSL). Each of these phenomena has its specific potential for dating various archaeological materials in the time range from medieval back to palaeolithic periods, or, speaking in geological terms, for dating of Holocene and late Pleistocene objects. The OSL and IRSL techniques are sometimes treated together as 'optical dating'. The luminescence techniques differ from other major dating techniques, such as 14 C, essentially by their applicability to inorganic materials, their wide age-range from about 100 years to more than 100,000 years and the kind of datable events which are the last exposure to heat or to light. (author). 10 refs., 3 figs.

  4. Luminescence dating

    International Nuclear Information System (INIS)

    Rieser, U.

    2009-01-01

    The luminescence techniques have evolved over the last 40 years to a powerful dating instrument in archaeology and geoscience. Depending on how the luminescence is stimulated, one distinguishes the phenomena of thermoluminescence (TL), optically stimulated luminescence (OSL) and infrared stimulated luminescence (IRSL). Each of these phenomena has its specific potential for dating various archaeological materals in the time range from medieval back to palaeolithic periods, or, speaking in geological terms, for dating of Holocene and late Pleistocene objects. The OSL and IRSL techniques are sometimes treated together as 'optical dating'. The luminescence techniques differ from other major dating techniques, such as 14 C, essentially by their applicability to inorganic materials, their wide age-range from about 100 years to more than 100,000 years and the kind of datable events which are the last exposure to heat or to light. (author). 10 refs., 3 figs

  5. Luminescence dating

    International Nuclear Information System (INIS)

    Rieser, U.

    2013-01-01

    The luminescence techniques have evolved over the last 40 years to a powerful dating instrument in archaeology and geoscience. Depending on how the luminescence is stimulated, one distinguishes the phenomena of thermoluminescence (TL), optically stimulated luminescence (OSL) and infrared stimulated luminescence (IRSL). Each of these phenomena has its specific potential for dating various archaeological materials in the time range from medieval back to palaeolithic periods, or, speaking in geological terms, for dating of Holocene and late Pleistocene objects. The OSL and IRSL techniques are sometimes treated together as 'optical dating'. The luminescence techniques differ from other major dating techniques, such as 14 C, essentially by their applicability to inorganic materials, their wide age-range from about 100 years to more than 100,000 years and the kind of datable events which are the last exposure to heat or to light. (author). 10 refs., 3 figs.

  6. Metrology challenges for high-rate nanomanufacturing of polymer structures

    Science.gov (United States)

    Mead, Joey; Barry, Carol; Busnaina, Ahmed; Isaacs, Jacqueline

    2012-10-01

    The transfer of nanoscience accomplishments into commercial products is hindered by the lack of understanding of barriers to nanoscale manufacturing. We have developed a number of nanomanufacturing processes that leverage available high-rate plastics fabrication technologies. These processes include directed assembly of a variety of nanoelements, such as nanoparticles and nanotubes, which are then transferred onto a polymer substrate for the fabrication of conformal/flexible electronic materials, among other applications. These assembly processes utilize both electric fields and/or chemical functionalization. Conducting polymers and carbon nanotubes have been successfully transferred to a polymer substrate in times less than 5 minutes, which is commercially relevant and can be utilized in a continuous (reel to reel/roll to roll) process. Other processes include continuous high volume mixing of nanoelements (CNTs, etc) into polymers, multi-layer extrusion and 3D injection molding of polymer structures. These nanomanufacturing processes can be used for wide range of applications, including EMI shielding, flexible electronics, structural materials, and novel sensors (specifically for chem/bio detection). Current techniques to characterize the quality and efficacy of the processes are quite slow. Moreover, the instrumentation and metrology needs for these manufacturing processes are varied and challenging. Novel, rapid, in-line metrology to enable the commercialization of these processes is critically needed. This talk will explore the necessary measurement needs for polymer based nanomanufacturing processes for both step and continuous (reel to reel/roll to roll) processes.

  7. Luminescence and luminescence quenching of highly efficient Y2Mo4O15:Eu(3+) phosphors and ceramics.

    Science.gov (United States)

    Janulevicius, Matas; Marmokas, Paulius; Misevicius, Martynas; Grigorjevaite, Julija; Mikoliunaite, Lina; Sakirzanovas, Simas; Katelnikovas, Arturas

    2016-05-16

    A good LED phosphor must possess strong enough absorption, high quantum yields, colour purity, and quenching temperatures. Our synthesized Y2Mo4O15:Eu(3+) phosphors possess all of these properties. Excitation of these materials with near-UV or blue radiation yields bright red emission and the colour coordinates are relatively stable upon temperature increase. Furthermore, samples doped with 50% Eu(3+) showed quantum yields up to 85%, what is suitable for commercial application. Temperature dependent emission spectra revealed that heavily Eu(3+) doped phosphors possess stable emission up to 400 K and lose half of the efficiency only at 515 K. In addition, ceramic disks of Y2Mo4O15:75%Eu(3+) phosphor with thickness of 0.71 and 0.98 mm were prepared and it turned out that they efficiently convert radiation of 375 and 400 nm LEDs to the red light, whereas combination with 455 nm LED yields purple colour.

  8. Luminescence and luminescence quenching of highly efficient Y2Mo4O15:Eu3+ phosphors and ceramics

    Science.gov (United States)

    Janulevicius, Matas; Marmokas, Paulius; Misevicius, Martynas; Grigorjevaite, Julija; Mikoliunaite, Lina; Sakirzanovas, Simas; Katelnikovas, Arturas

    2016-01-01

    A good LED phosphor must possess strong enough absorption, high quantum yields, colour purity, and quenching temperatures. Our synthesized Y2Mo4O15:Eu3+ phosphors possess all of these properties. Excitation of these materials with near-UV or blue radiation yields bright red emission and the colour coordinates are relatively stable upon temperature increase. Furthermore, samples doped with 50% Eu3+ showed quantum yields up to 85%, what is suitable for commercial application. Temperature dependent emission spectra revealed that heavily Eu3+ doped phosphors possess stable emission up to 400 K and lose half of the efficiency only at 515 K. In addition, ceramic disks of Y2Mo4O15:75%Eu3+ phosphor with thickness of 0.71 and 0.98 mm were prepared and it turned out that they efficiently convert radiation of 375 and 400 nm LEDs to the red light, whereas combination with 455 nm LED yields purple colour. PMID:27180941

  9. Highly luminescent and photostable quantum dot-silica monolith and its application to light-emitting diodes.

    Science.gov (United States)

    Jun, Shinae; Lee, Junho; Jang, Eunjoo

    2013-02-26

    A highly luminescent and photostable quantum dot-silica monolith (QD-SM) substance was prepared by preliminary surface exchange of the QDs and base-catalyzed sol-gel condensation of silica. The SM was heavily doped with 6-mercaptohexanol exchanged QDs up to 12 vol % (26 wt %) without particle aggregation. Propylamine catalyst was important in maintaining the original luminescence of the QDs in the SM during sol-gel condensation. The silica layer was a good barrier against oxygen and moisture, so that the QD-SM maintained its initial luminescence after high-power UV radiation (∼1 W) for 200 h and through the 150 °C LED encapsulant curing process. Green and red light-emitting QD-SMs were applied as color-converting layers on blue LEDs, and the external quantum efficiency reached up to 89% for the green QD-SM and 63% for the red one. A white LED made with a mixture of green and red QDs in the SM, in which the color coordinate was adjusted at (0.23, 0.21) in CIE1931 color space for a backlight application, showed an efficacy of 47 lm/W, the highest value yet reported.

  10. High luminescent L-cysteine capped CdTe quantum dots prepared at different reaction times

    Science.gov (United States)

    Kiprotich, Sharon; Onani, Martin O.; Dejene, Francis B.

    2018-04-01

    This paper reports a facile synthesis route of high luminescent L-cysteine capped CdTe quantum dots (QDs). The effect of reaction time on the growth mechanism, optical and physical properties of the CdTe QDs was investigated in order to find the suitability of them towards optical and medical applications. The representative high-resolution transmission microscopy (HRTEM) analysis showed that the as-obtained CdTe QDs appeared as spherical particles with excellent monodispersity. The images exhibited clear lattice fringes which are indicative of good crystallinity. The X-ray diffraction (XRD) pattern displayed polycrystalline nature of the QDs which correspond well to zinc blende phase of bulk CdTe. The crystallite sizes calculated from the Scherrer equation were less than 10 nm for different reaction times which were in close agreement with the values estimated from HRTEM. An increase in reaction time improved crystallinity of the sample as explained by highest peak intensity of the XRD supported by the photoluminescence emission spectra which showed high intensity at a longer growth time. It was observed that for prolonged growth time the emission bands were red shifted from about 517-557 nm for 5-180 min of reaction time due to increase in particle sizes. Ultraviolet and visible analysis displayed well-resolved absorption bands which were red shifted upon an increase in reaction time. There was an inverse relation between the band gap and reaction time. Optical band gap decreases from 3.98 to 2.59 eV with the increase in reaction time from 15 to 180 min.

  11. Thermal Protective Coating for High Temperature Polymer Composites

    Science.gov (United States)

    Barron, Andrew R.

    1999-01-01

    The central theme of this research is the application of carboxylate-alumoxane nanoparticles as precursors to thermally protective coatings for high temperature polymer composites. In addition, we will investigate the application of carboxylate-alumoxane nanoparticle as a component to polymer composites. The objective of this research was the high temperature protection of polymer composites via novel chemistry. The significance of this research is the development of a low cost and highly flexible synthetic methodology, with a compatible processing technique, for the fabrication of high temperature polymer composites. We proposed to accomplish this broad goal through the use of a class of ceramic precursor material, alumoxanes. Alumoxanes are nano-particles with a boehmite-like structure and an organic periphery. The technical goals of this program are to prepare and evaluate water soluble carboxylate-alumoxane for the preparation of ceramic coatings on polymer substrates. Our proposed approach is attractive since proof of concept has been demonstrated under the NRA 96-LeRC-1 Technology for Advanced High Temperature Gas Turbine Engines, HITEMP Program. For example, carbon and Kevlar(tm) fibers and matting have been successfully coated with ceramic thermally protective layers.

  12. Extrudable polymer-polymer composites based on ultra-high molecular weight polyethylene

    Science.gov (United States)

    Panin, S. V.; Kornienko, L. A.; Alexenko, V. O.; Buslovich, D. G.; Dontsov, Yu. V.

    2017-12-01

    Mechanical and tribotechnical characteristics of polymer-polymeric composites of UHMWPE are studied with the aim of developing extrudable, wear-resistant, self-lubricant polymer mixtures for Additive Manufacturing (AM). The motivation of the study is their further application as feedstocks for 3D printing. Blends of UHMWPE with graft- and block copolymers of low-density polyethylene (HDPE-g-VTMS, HDPE-g-SMA, HDPE-b-EVA), polypropylene (PP), block copolymers of polypropylene and polyamide with linear low density polyethylene (PP-b-LLDPE, PA-b-LLDPE), as well as cross-linked polyethylene (PEX-b), are examined. The choice of compatible polymer components for an ultra- high molecular weight matrix for increasing processability (extrudability) is motivated by the search for commercially available and efficient additives aimed at developing wear-resistant extrudable polymer composites for additive manufacturing. The extrudability, mechanical properties and wear resistance of UHMWPE-based polymer-polymeric composites under sliding friction with different velocities and loads are studied.

  13. Melting point of polymers under high pressure Part I: Influence of the polymer properties

    International Nuclear Information System (INIS)

    Seeger, Andreas; Freitag, Detlef; Freidel, Frank; Luft, Gerhard

    2004-01-01

    The pressure dependence of the melting point of various polymers including homo- and copolymers (HDPE, LDPE, PP and ethylene vinyl acetate copolymers (EVA)) was investigated under nitrogen atmosphere up to 330 MPa within a high pressure differential thermal analysis cell designed by our group. The properties of the polymers (vinylacetate content, melt flow index, molecular weight, isotactic index, crystallinity, density, and frequency of branching) have been correlated with the change of the melting point under pressure (dT m /dp). It could be shown that the melting point always increases linearly with pressure up to 330 MPa. The pressure dependence was found to be in the range of 11-17 K/(100 MPa). From these results it is possible to approximate dT m /dp using the enthalpy of fusion of the polymers at ambient pressure

  14. Luminescence enhancement of ZnO-poly(methylmethacrylate) nanocomposite films by incorporation of crystalline BaTiO_3 nanoparticles

    International Nuclear Information System (INIS)

    Kanamori, Tsuyoshi; Han, Yu; Nagao, Daisuke; Kamezawa, Nao; Ishii, Haruyuki; Konno, Mikio

    2016-01-01

    Highlights: • Dielectric barium titanate (BT) nanoparticles incorporated into luminescence films. • Luminescence intensities increased by the BT nanoparticle incorporation. • Incorporation of highly dielectric nanoparticles effective for luminescence enhancement. - Abstract: Incorporation of highly dielectric nanoparticles into luminescent ZnO-polymethylmethacrylate (PMMA) nanocomposite films was undertaken to examine the effect of nanoparticle incorporation on luminescence intensity of the nanocomposite films. ZnO nanoparticles were prepared as inorganic phosphors by a precipitation method. The ZnO nanoparticles were then surface-modified with 3-methacryloxypropyltrimethoxysilane (MPTMS) to be used for fabrication of the ZnO-PMMA nanocomposite film. Barium titanate (BT) nanoparticles were synthesized with a sol-gel method as the highly dielectric nanoparticles, which were also surface-modified with the MPTMS for the incorporation into the nanocomposite films. Luminescence intensity of the nanocomposite films was successfully increased by the nanoparticle incorporation up to a BT content around 15 vol%. The luminescence intensity higher than that measured for the nanocomposite films incorporating SiO_2 nanoparticles indicated that the incorporation of highly dielectric nanoparticles was an effective approach to enhance the luminescence of ZnO nanoparticles in the polymer thin films.

  15. Highly conductive polymers: superconductivity in nanochannels or an experimental artifact?

    International Nuclear Information System (INIS)

    Hayden, Harley; Park, Seongho; Zhirnov, Victor; Cavin, Ralph; Kohl, Paul A.

    2010-01-01

    There is a significant body of literature concerning the potential formation of electrically conductive moieties in polymeric materials. The conductive path is not associated with conjugation (such as in the case of 'conductive polymers') but rather associated with a new conductivity route. The objective of the experiments reported herein was to provide insight into the phenomenon of unusually high electrical conductivity in polymers that have been reported by several research groups. In some experiments, the test apparatus did indeed indicate high levels of conductance. Arguments pro and con for high conductivity based on known physical phenomena and the collected data were examined.

  16. Synthesis, crystal structures, and luminescent properties of Cd(II) coordination polymers assembled from semi-rigid multi-dentate N-containing ligand

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Gang; Shao, Kui-Zhan; Chen, Lei; Liu, Xin-Xin [Institute of Functional Material Chemistry, Faculty of Chemistry, Northeast Normal University, Changchun 130024, Jilin (China); Su, Zhong-Min, E-mail: zmsu@nenu.edu.cn [Institute of Functional Material Chemistry, Faculty of Chemistry, Northeast Normal University, Changchun 130024, Jilin (China); Ma, Jian-Fang [Institute of Functional Material Chemistry, Faculty of Chemistry, Northeast Normal University, Changchun 130024, Jilin (China)

    2012-12-15

    Three new polymers, [Cd(L){sub 2}(H{sub 2}O){sub 2}]{sub n} (1), [Cd{sub 3}(L){sub 2}({mu}{sub 3}-OH){sub 2}({mu}{sub 2}-Cl){sub 2}(H{sub 2}O){sub 2}]{sub n} (2), {l_brace}[Cd{sub 2}(L){sub 2}(nic){sub 2}(H{sub 2}O){sub 2}]{center_dot}H{sub 2}O{r_brace}{sub n} (3) (HL=5-(4-((1H-1,2,4-triazol-1-yl)methyl)phenyl)-1H-tetrazole, Hnic=nicotinic acid) have been prepared and structurally characterized. Compounds 1 and 2 display 2D monomolecular layers built by the inter-linking single helical chains and L{sup -} ligands connecting chain-like [Cd({mu}{sub 3}-OH)({mu}{sub 2}-Cl)]{sub n} secondary building units, respectively. Compound 3 is constructed from the mixed ligands and possesses a (3,4)-connected framework with (4{center_dot}8{sup 2})(4{center_dot}8{sup 2}{center_dot}10{sup 3}) topology. Moreover, the fluorescent properties of HL ligand and compounds 1-3 are also been investigated. - Graphical abstract: Three new coordination polymers based on the semi-rigid multidentate N-donor ligand have been successfully synthesized by hydrothermal reaction. Complexes 1 and 2 exhibit the 2D layers formed by inter-linking single helices and L{sup -} anions bridging 1D chain-like SBUs, respectively. Complex 3 is buit by L{sup -} and assistant nic{sup -} ligands connecting metal centers and possesses a (3,4)-connected framework with (4 Multiplication-Sign 8{sup 2})(4 Multiplication-Sign 8{sup 2} Multiplication-Sign 10{sup 3}) topology. Moreover, these complexes display fluorescent properties indicating that they may have potential applications as optical materials. Highlights: Black-Right-Pointing-Pointer Three Cd-compounds were prepared from semi-rigid HL ligand with different N-containing groups. Black-Right-Pointing-Pointer They exhibit diverse structures from 2D monomolecular layer to 3D covalent framework. Black-Right-Pointing-Pointer The HL ligands displayed various coordination modes under different reaction conditions. Black-Right-Pointing-Pointer These compounds exhibit

  17. A nonconjugated radical polymer glass with high electrical conductivity

    Science.gov (United States)

    Joo, Yongho; Agarkar, Varad; Sung, Seung Hyun; Savoie, Brett M.; Boudouris, Bryan W.

    2018-03-01

    Solid-state conducting polymers usually have highly conjugated macromolecular backbones and require intentional doping in order to achieve high electrical conductivities. Conversely, single-component, charge-neutral macromolecules could be synthetically simpler and have improved processibility and ambient stability. We show that poly(4-glycidyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl), a nonconjugated radical polymer with a subambient glass transition temperature, underwent rapid solid-state charge transfer reactions and had an electrical conductivity of up to 28 siemens per meter over channel lengths up to 0.6 micrometers. The charge transport through the radical polymer film was enabled with thermal annealing at 80°C, which allowed for the formation of a percolating network of open-shell sites in electronic communication with one another. The electrical conductivity was not enhanced by intentional doping, and thin films of this material showed high optical transparency.

  18. Synthesis and spectroscopic behavior of highly luminescent Eu 3+-dibenzoylmethanate (DBM) complexes with sulfoxide ligands

    Science.gov (United States)

    Niyama, E.; Brito, H. F.; Cremona, M.; Teotonio, E. E. S.; Reyes, R.; Brito, G. E. S.; Felinto, M. C. F. C.

    2005-09-01

    In this paper the synthesis, characterization and photoluminescent behavior of the [RE(DBM) 3L 2] complexes (RE = Gd and Eu) with a variety of sulfoxide ligands; L = benzyl sulfoxide (DBSO), methyl sulfoxide (DMSO), phenyl sulfoxide (DPSO) and p-tolyl sulfoxide (PTSO) have been investigated in solid state. The emission spectra of the Eu 3+-β-diketonate complexes show characteristics narrow bands arising from the 5D 0 → 7F J ( J = 0-4) transitions, which are split according to the selection rule for C n, C nv or C s site symmetries. The experimental Judd-Ofelt intensity parameters ( Ω2 and Ω4), radiative ( Arad) and non-radiative ( Anrad) decay rates, and R02 for the europium complexes have been determined and compared. The highest value of Ω2 (61.9 × 10 -20 cm 2) was obtained to the complex with PTSO ligand, indicating that Eu 3+ ion is in the highly polarizable chemical environment. The higher values of the experimental quantum yield ( q) and emission quantum efficiency of the emitter 5D 0 level ( η) for the Eu-complexes with DMSO, DBSO and PTSO sulfoxides suggest that these complexes are promising Light Conversion Molecular Devices (LCMDs). The lower value of quantum yield ( q = 1%), for the hydrated complex [Eu(DBM) 3(H 2O)], indicates that the luminescence quenching occurs via multiphonon relaxation by coupling with the OH-oscillators from water molecule coordinated to rare earth ion. The pure red emission of the Eu-complexes has been confirmed by ( x, y) color coordinates.

  19. CHAPTER 3. High-performance Organic Photovoltaic Donor Polymers

    KAUST Repository

    Wadsworth, Andrew

    2017-11-08

    The field of organic photovoltaics has advanced a great deal over the last decade, with device efficiencies now exceeding 11%. A large part of this success can be attributed to the development of donor polymer materials, from their humble beginnings as homopolymers to the highly tuned push-pull copolymer and terpolymer materials that are now being reported on a regular basis. Through the careful use of chemical modification, it has been possible to design and synthesize a wide variety of donor polymers, allowing optimization of both the optoelectronic and structural properties of the materials. In doing so, more favourable active layer blends have been achieved and therefore significant improvements in device performance have been observed. Herein we discuss how the chemical design of donor polymers for organic photovoltaics has led to the emergence of high-performance materials.

  20. CHAPTER 3. High-performance Organic Photovoltaic Donor Polymers

    KAUST Repository

    Wadsworth, Andrew; Baran, Derya; Gorman, Jeffrey; McCulloch, Iain

    2017-01-01

    The field of organic photovoltaics has advanced a great deal over the last decade, with device efficiencies now exceeding 11%. A large part of this success can be attributed to the development of donor polymer materials, from their humble beginnings as homopolymers to the highly tuned push-pull copolymer and terpolymer materials that are now being reported on a regular basis. Through the careful use of chemical modification, it has been possible to design and synthesize a wide variety of donor polymers, allowing optimization of both the optoelectronic and structural properties of the materials. In doing so, more favourable active layer blends have been achieved and therefore significant improvements in device performance have been observed. Herein we discuss how the chemical design of donor polymers for organic photovoltaics has led to the emergence of high-performance materials.

  1. Highly luminescent, high-indium-content InGaN film with uniform composition and full misfit-strain relaxation

    Science.gov (United States)

    Fischer, A. M.; Wei, Y. O.; Ponce, F. A.; Moseley, M.; Gunning, B.; Doolittle, W. A.

    2013-09-01

    We have studied the properties of thick InxGa1-xN films, with indium content ranging from x ˜ 0.22 to 0.67, grown by metal-modulated epitaxy. While the low indium-content films exhibit high density of stacking faults and dislocations, a significant improvement in the crystalline quality and optical properties has been observed starting at x ˜ 0.6. Surprisingly, the InxGa1-xN film with x ˜ 0.67 exhibits high luminescence intensity, low defect density, and uniform full lattice-mismatch strain relaxation. The efficient strain relaxation is shown to be due to a critical thickness close to the monolayer range. These films were grown at low temperatures (˜400 °C) to facilitate indium incorporation and with precursor modulation to enhance surface morphology and metal adlayer diffusion. These findings should contribute to the development of growth techniques for nitride semiconductors under high lattice misfit conditions.

  2. Quickly updatable hologram images with high performance photorefractive polymer composites

    Science.gov (United States)

    Tsutsumi, Naoto; Kinashi, Kenji; Nonomura, Asato; Sakai, Wataru

    2012-02-01

    We present here quickly updatable hologram images using high performance photorefractive (PR) polymer composite based on poly(N-vinyl carbazole) (PVCz). PVCz is one of the pioneer materials for photoconductive polymer. PVCz/7- DCST/CzEPA/TNF (44/35/20/1 by wt) gives high diffraction efficiency of 68 % at E = 45 V/μm with fast response speed. Response speed of optical diffraction is the key parameter for real-time 3D holographic display. Key parameter for obtaining quickly updatable hologram images is to control the glass transition temperature lower enough to enhance chromophore orientation. Object image of the reflected coin surface recorded with reference beam at 532 nm (green beam) in the PR polymer composite is simultaneously reconstructed using a red probe beam at 642 nm. Instead of using coin object, object image produced by a computer was displayed on a spatial light modulator (SLM) is used as an object for hologram. Reflected object beam from a SLM interfered with reference beam on PR polymer composite to record a hologram and simultaneously reconstructed by a red probe beam. Movie produced in a computer was recorded as a realtime hologram in the PR polymer composite and simultaneously clearly reconstructed with a video rate.

  3. Highly selective determination of methylmercury with methylmercury-imprinted polymers

    Energy Technology Data Exchange (ETDEWEB)

    Liu Yongwen [Department of Chemistry, Shanxi Datong University, Datong 037009 (China)]. E-mail: dtlyw@263.net; Zai Yunhui [School of Chemistry and Chemical Engineering of Lanzhou University, Lanzhou 730000 (China); Chang Xijun [School of Chemistry and Chemical Engineering of Lanzhou University, Lanzhou 730000 (China); Guo Yong [Department of Chemistry, Shanxi Datong University, Datong 037009 (China); Meng Shuangming [Department of Chemistry, Shanxi Datong University, Datong 037009 (China); Feng Feng [Department of Chemistry, Shanxi Datong University, Datong 037009 (China)

    2006-08-11

    Methylmercury-imprinted and non-imprinted polymers were prepared by formation monomer complex of methylmercury with (4-ethenylphenyl)-4-formate-6-phenyl-2,2'-bipyridine and thermally polymerizing with divinylbenzene (crosslinker) in the presence of 2,2'-azobisisobutyronitrile as initiator and subsequently leached with the acidic thiourea solution (1.0 mol L{sup -1} of thiourea and 4.0 mol L{sup -1} of HCl). In the same way, non-imprinted copolymers were prepared without methylmercury chloride added. The separation and preconcentration characteristics of the polymers for methylmercury were investigated by batch and column procedures. The results demonstrated that the methylmercury-imprinted polymers had higher adsorption capacity (170 {mu}mol g{sup -1} of dry microbeads) and good selectivity for methylmercury compared to non-imprinted polymers. The distribution ratio (D) values of the methylmercury-imprinted polymers increased for methylmercury with respect to both D values of Hg(II), Cu(II), Zn(II), Cd(II) and non-imprinted polymers. The relatively selective factor ({alpha} {sub r}) values of CH{sub 3}Hg{sup +}/Hg(II), CH{sub 3}Hg{sup +}/Cu(II), CH{sub 3}Hg{sup +}/Zn(II), and CH{sub 3}Hg{sup +}/Cd(II) are 24.0, 46.7, 50.7, and 40.2, which are greater than 1. The methylmercury-imprinted polymers can be used at least twenty times with recoveries no less than 95%. Based on the packed columns with methylmercury-imprinted polymers, a highly selective solid-phase extraction (SPE) and preconcentration method for methylmercury was developed. The metal ion imprinted polymer solid-phase extraction (MIIP-SPE) preconcentration procedure showed a linear calibration curve within concentration range from 0.093 to 22 {mu}g L{sup -1}. The detection limit and quantification limit were 0.041 and 0.093 {mu}g L{sup -1} (3{sigma}) for cold vapor atomic absorption spectrometry (CVAAS). The relative standard deviation of the 10 replicate determinations was 3.5% for the

  4. Luminescence of the SrCl2:Pr crystals under high-energy excitation

    International Nuclear Information System (INIS)

    Antonyak, O.T.; Voloshinovskii, A.S.; Vistovskyy, V.V.; Stryganyuk, G.B.; Kregel, O.P.

    2014-01-01

    The present research was carried out in order to elucidate the mechanisms of energy transfer from the crystal lattice to Pr 3+ ions in SrCl 2 . The luminescence excitation and emission spectra as well as luminescence kinetics of the SrCl 2 :Pr single crystals containing 0.2 mol% Pr were investigated at 300 and 10 K using the vacuum ultraviolet (VUV) synchrotron radiation. The X-ray excited luminescence spectra of the SrCl 2 :Pr (C Pr =0.2 and 0.5 mol%) and SrCl 2 :Pr, K (C Pr =1.5 mol%; C K =1.5 mol%) crystals were studied at 294 and 80 K. Under optical excitation of the samples in the Pr 3+ absorption bands, there were observed five fast ultraviolet emissions assigned to the 4f 1 5d→4f 2 transitions, and two long-wave bands corresponding to the f–f transitions. Furthermore, the intrinsic emission bands of SrCl 2 were observed at 10 K. The X-ray excited luminescence spectrum of the SrCl 2 :Pr crystal containing 0.2 mol% Pr, besides intrinsic emission band near 400 nm, has got a long-wave band at about 490 nm of the Pr 3+ centers. There were not observed any emission bands of the Pr 3+ centers corresponding to the 4f 1 5d–4f 2 transitions in the X-ray excited luminescence spectrum of the SrCl 2 :Pr crystal. The possible mechanisms of energy transfer from the SrCl 2 matrix to the Pr 3+ centers are discussed. -- Highlights: • Spectral-luminescent properties of SrCl 2 :Pr have been investigated. • The identification of emission 4f–4f and 5d–4f bands of Pr 3+ ions was performed. • Adding of potassium prevents clustering of the Pr 3+ centers in the SrCl 2 :Pr, K crystals. • Under X-ray excitation at 80–300 K only Pr 3+ 4f–4f and intrinsic emission is observed

  5. Alternative High Performance Polymers for Ablative Thermal Protection Systems

    Science.gov (United States)

    Boghozian, Tane; Stackpoole, Mairead; Gonzales, Greg

    2015-01-01

    Ablative thermal protection systems are commonly used as protection from the intense heat during re-entry of a space vehicle and have been used successfully on many missions including Stardust and Mars Science Laboratory both of which used PICA - a phenolic based ablator. Historically, phenolic resin has served as the ablative polymer for many TPS systems. However, it has limitations in both processing and properties such as char yield, glass transition temperature and char stability. Therefore alternative high performance polymers are being considered including cyanate ester resin, polyimide, and polybenzoxazine. Thermal and mechanical properties of these resin systems were characterized and compared with phenolic resin.

  6. Universal Scaling in Highly Doped Conducting Polymer Films

    NARCIS (Netherlands)

    Kronemeijer, A. J.; Huisman, E. H.; Katsouras, I.; van Hal, P. A.; Geuns, T. C. T.; Blom, P. W. M.; van der Molen, S. J.; de Leeuw, D. M.

    2010-01-01

    Electrical transport of a highly doped disordered conducting polymer, viz. poly-3,4-ethylenedioxythiophene stabilized with poly-4-styrenesulphonic acid, is investigated as a function of bias and temperature. The transport shows universal power-law scaling with both bias and temperature. All

  7. Universal scaling in highly doped conducting polymer films

    NARCIS (Netherlands)

    Kronemeijer, A.J.; Huisman, E.H.; Katsouras, I.; Hal, P.A. van; Geuns, T.C.T.; Blom, P.W.M.; Molen, S.J. van der; Leeuw, D.M. de

    2010-01-01

    Electrical transport of a highly doped disordered conducting polymer, viz. poly-3,4-ethylenedioxythiophene stabilized with poly-4-styrenesulphonic acid, is investigated as a function of bias and temperature. The transport shows universal power-law scaling with both bias and temperature. All

  8. High speed electro optic polymer micro-ringresonator

    NARCIS (Netherlands)

    Leinse, Arne; Diemeer, Mart; Driessen, A.

    2004-01-01

    An electro-optic polymer micro-ring resonator for high speed modulation was designed, realized and characterized. The design of layer-stack and electrodes was done such that modulation frequencies up till 1 GHz should be possible. The device consists of a ridge waveguide, defined in a negative

  9. A high sensitivity optically stimulated luminescence scanning system for measurement of single sand-sized grains

    DEFF Research Database (Denmark)

    Duller, G.A.T.; Bøtter-Jensen, L.; Kohsiek, P.

    1999-01-01

    An instrument has been designed for the routine analysis of the optically stimulated luminescence signal from single grains of sand. The system is capable of analysing over 3000 individual grains in a single measurement sequence, and the OSL signal from each grain can be read in less than 3 s....... The design principles are described, along with preliminary measurements that illustrate the operation of the system and its capabilities....

  10. A Highly Luminescent Hexanuclear Molybdenum Cluster - A Promising Candidate toward Photoactive Materials

    Czech Academy of Sciences Publication Activity Database

    Kirakci, Kaplan; Kubát, Pavel; Dušek, Michal; Fejfarová, Karla; Šícha, Václav; Mosinger, Jiří; Lang, Kamil

    2012-01-01

    Roč. 2012, č. 19 (2012), s. 3107-3111 ISSN 1434-1948 R&D Projects: GA ČR(CZ) GAP204/11/0809; GA ČR GAP208/10/1678 Institutional support: RVO:61388980 ; RVO:61388955 ; RVO:68378271 Keywords : cluster compounds * luminescence * molybdenum * organic-inorganic hybrid composites * singlet oxygen Subject RIV: CA - Inorganic Chemistry Impact factor: 3.120, year: 2012

  11. Luminescence and scintillation of Ce.sup.3+./sup.- doped high silica glass

    Czech Academy of Sciences Publication Activity Database

    Chewpraditkul, W.; Shen, Y.; Chen, D.; Yu, B.; Průša, Petr; Nikl, Martin; Beitlerová, Alena; Wanarak, C.

    2012-01-01

    Roč. 34, č. 11 (2012), s. 1762-1766 ISSN 0925-3467 R&D Projects: GA MŠk LH12185 Institutional research plan: CEZ:AV0Z10100521 Keywords : Ce 3+ * luminescence * porous materials * scintillation * photoluminescence decay Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.918, year: 2012 http://dx.doi.org/10.1016/j.optmat.2012.04.012

  12. 4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran (DCM)-doping density dependence of luminescence spectra and white emission in polymer light-emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Akinori; Hosokawa, Takeshi; Haishi, Motoki; Ohtani, Naoki [Department of Electronics, Doshisha University, Tatara-Miyakodani, Kyotanabe-shi, Kyoto (Japan)

    2009-01-15

    We fabricated white polymer light-emitting diodes (PLEDs), in which the active region is doped with a low-weight molecule. The host polymer material is Poly(9,9-didodecyl-fluorenyl-2,7-yleneethylnylene) (PFO), while the guest luminescent low-weight-molecule is 4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran (DCM). The photoluminescence (PL) and electroluminescence (EL) spectra strongly depend on DCM-doping-density. However, the most suitable DCM-doping-densities for white emissions in PL and EL are slightly different. This discrepancy is caused by the difference in excitation efficiencies. The photo-excitation system for PL measurement is better than the current injection for generating carriers efficiently. Thus, the realization of the white EL signal requires the larger DCM-doping-density than that of the white PL signal. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  13. High resolution luminescence chronology for Xiashu Loess deposits of Southeastern China

    Science.gov (United States)

    Yi, Shuangwen; Li, Xusheng; Han, Zhiyong; Lu, Huayu; Liu, Jinfeng; Wu, Jiang

    2018-04-01

    Loess deposits in Xiashu are representative of such deposits in Southeastern China that are mainly distributed in the middle and lower reaches of the Yangtze River valley. These loess-paleosol sequences provide a key archive of past climate change in humid, subtropical regions. However, the ages of the sequences are not well constrained. In this study, the standard quartz single-aliquot regenerative (SAR) dose optically stimulated luminescence (OSL) and K-feldspar post-infrared infrared stimulated luminescence (post-IR IRSL; pIRIR290) methods are used to date two loess sequences in Nanjing region. Our results show that quartz SAR OSL and K-feldspar pIRIR290 ages are more or less indistinguishable from one another up to ∼50 ka. Beyond this age, the K-feldspar pIRIR ages increased systematically with deposition depth, agreeing well with the expected ages as far as ∼200 ka. On the basis of a fully independently-dated timescale, we are therefore able to propose, for the first time, a new age model for the Xiashu Loess deposits accumulated since the penultimate interglacial period. Using our newly obtained luminescence dating ages, we observe a marked difference between the loess accumulation rates in the two sequences, potentially forced by regional depositional processes and loess preservation.

  14. High Energy Density Polymer Film Capacitors

    National Research Council Canada - National Science Library

    Boufelfel, Ali

    2006-01-01

    High-energy-density capacitors that are compact and light-weight are extremely valuable in a number of critical DoD systems that include portable field equipment, pulsed lasers, detection equipment...

  15. Intrinsically Microporous Polymer Membranes for High Performance Gas Separation

    KAUST Repository

    Swaidan, Raja

    2014-11-01

    This dissertation addresses the rational design of intrinsically microporous solutionprocessable polyimides and ladder polymers for highly permeable and highly selective gas transport in cornerstone applications of membrane-based gas separation – that is, air enrichment, hydrogen recovery and natural gas sweetening. By virtue of rigid and contorted chains that pack inefficiently in the solid state, polymers of intrinsic microporosity (PIMs) have the potential to unite the solution-processability, mechanical flexibility and organic tunability of commercially relevant polymers with the microporosity characteristics of porous crystalline materials. The performance enhancements of PIMs over conventional low-free-volume polymers have been primarily permeability-driven, compromising the selectivity essential to commercial viability. An approach to unite high permeability with high selectivity for performance transcending the state-of-the-art in air and hydrogen separations was demonstrated via a fused-ring integration of a three-dimensional, shape persistent triptycene moiety optimally substituted with short, branched isopropyl chains at the 9,10-bridgeheads into a highly inflexible backbone. The resulting polymers exhibited selectivities (i.e., O2/N2, H2/N2, H2/CH4) similar to or higher than commercial materials matched with permeabilities up to three hundred times higher. However, the intra-chain rigidity central to such conventional PIM-design principles was not a singular solution to suppression of CO2-induced plasticization in CO2/CH4 mixedgas separations. Plasticization diminishes the sieving capacity of the membrane, resulting in costly hydrocarbon losses that have significantly limited the commercialization of new polymers. Unexpectedly, the most permeable and selective PIMs designed for air and hydrogen separations strongly plasticized in 50:50 CO2/CH4 mixtures, enduring up to three-fold increases in mixed-gas CH4 permeability by 30 bar and strong drops in

  16. Studies on highly luminescent AgInS{sub 2} and Ag–Zn–In–S quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Xiang, Weidong, E-mail: xiangweidong001@126.com [College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou 325035 (China); College of Materials Science and Engineering, Tongji University, Shanghai 201804 (China); Xie, Cuiping; Wang, Jing; Zhong, Jiasong; Liang, Xiaojuan; Yang, Hailong; Luo, Le [College of Materials Science and Engineering, Tongji University, Shanghai 201804 (China); Chen, Zhaoping [College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou 325035 (China)

    2014-03-05

    Highlights: • The quantum yield of the obtained ternary AgInS{sub 2} QDs was up to 62% with the emission peak of 642 nm under the excitation of 460 nm. • Colorful luminescent Ag–Zn–In–S QDs were obtained by adding Zn salts directly as well as Ag and In precursors. • The obtained highly luminescent quantum dots showed promising applications in the white light emitting diodes (W-LED). • The electroluminescence (EL) of AgInS{sub 2} QDs was observed in QD-LED device. -- Abstract: Silver indium sulfide (AIS) quantum dots (QDs) with different Ag/In molar ratios were synthesized via a hot-injection method. Intense photoluminescence (PL) originating from the donor–acceptor pair recombination were observed for all the samples and the emission peak blue-shifted from 739 to 632 nm, being similar to the behavior of the absorption onset as the Ag/In ratios decreased. The highest PL quantum yield (QY) of the obtained ternary AIS QDs was ca. 62% with an optimum ratio of Ag/In = 1/4. Compared with AIS QDs, when Zn ions were introduced, the absorption spectra of the obtained quaternary Ag–Zn–In–S QDs were blue-shifted, and their emission peaks moved to higher energies accordingly, showing a tunable emission from red to green by altering the band gap energy. In order to further study the electroluminescence (EL) as well as looking forward to the applications in the optoelectronic devices of the obtained highly luminescent nanoparticles, the colloidal AIS QDs were deposited as thin films to the sandwich-like structured QD-LED. The experimental results showed that the obtained EL device exhibited EL emission originated from QDs thin films by adjusting the turn on voltage, which is for the first time to realize EL of AIS QDs in such QD-LED.

  17. High field dielectric properties of anisotropic polymer-ceramic composites

    International Nuclear Information System (INIS)

    Tomer, V.; Randall, C. A.

    2008-01-01

    Using dielectrophoretic assembly, we create anisotropic composites of BaTiO 3 particles in a silicone elastomer thermoset polymer. We study a variety of electrical properties in these composites, i.e., permittivity, dielectric breakdown, and energy density as function of ceramic volume fraction and connectivity. The recoverable energy density of these electric-field-structured composites is found to be highly dependent on the anisotropy present in the system. Our results indicate that x-y-aligned composites exhibit higher breakdown strengths along with large recoverable energy densities when compared to 0-3 composites. This demonstrates that engineered anisotropy can be employed to control dielectric breakdown strengths and nonlinear conduction at high fields in heterogeneous systems. Consequently, manipulation of anisotropy in high-field dielectric properties can be exploited for the development of high energy density polymer-ceramic systems

  18. A high brightness probe of polymer nanoparticles for biological imaging

    Science.gov (United States)

    Zhou, Sirong; Zhu, Jiarong; Li, Yaping; Feng, Liheng

    2018-03-01

    Conjugated polymer nanoparticles (CPNs) with high brightness in long wavelength region were prepared by the nano-precipitation method. Based on fluorescence resonance energy transfer (FRET) mechanism, the high brightness property of the CPNs was realized by four different emission polymers. Dynamic light scattering (DLS) and scanning electron microscopy (SEM) displayed that the CPNs possessed a spherical structure and an average diameter of 75 nm. Analysis assays showed that the CPNs had excellent biocompatibility, good photostability and low cytotoxicity. The CPNs were bio-modified with a cell penetrating peptide (Tat, a targeted element) through covalent link. Based on the entire wave fluorescence emission, the functionalized CPNs1-4 can meet multichannel and high throughput assays in cell and organ imaging. The contribution of the work lies in not only providing a new way to obtain a high brightness imaging probe in long wavelength region, but also using targeted cell and organ imaging.

  19. Radiation chemistry of high polymers. Final report

    International Nuclear Information System (INIS)

    Dole, M.; Welch, R.A.

    1977-01-01

    Work on calibrating the radiation intensity in our γ-ray source as a function of height and horizontal displacement was completed. For extended chain (high crystallinity) polyethylene (PE) before and after quenching from the melt irradiated at room temperature, the crosslinking yield increased twofold on lowering the crystallinity from 96 to 70%. The G-value for alkyl radical production was about 75% higher in the quenched extended chain sample as compared to the value before quenching. The G (alkyl) values were determined for irradiations at 77K. The rate of decay of the alkyl radicals in PE samples of single crystals having different stem lengths was studied at 80 and 85 0 . It was found that the mole fraction of the slowly decaying free radicals increased with the stem length. Hydrogen gas was found to catalyze both the slow and fast decays. Because hydrogen does not dissolve in the crystalline regions of the PE, the catalytic effect must occur at the amorphous boundary of the crystalline stems. With respect to the kinetics of the allyl radical, either it was found that the data could be explained in terms of two simultaneous but spatially separated second order reactions. As the temperature is raised to 135 0 , the two reactions merge into one. Hydrogen gas has no effect on the decay of the allyl radicals. In the case of the highly crystalline extended chain samples, the allyl decay in some cases follows the simple kinetic equation (1/c) - (1/c 0 ) = k√t, where k is called a time independent diffusion controlled reaction rate constant. The less the crystallinity of the sample the greater the k constant. A preliminary study of isotactic polypropylene (PP) was carried out and a definite hydrogen gas catalysis of the free radical decay in PP was seen. Similarly in crystalline 1-leucine the hydrogen catalytic effect could also be clearly demonstrated

  20. The Role of Polymer Fractionation in Energetic Losses and Charge Carrier Lifetimes of Polymer: Fullerene Solar Cells

    KAUST Repository

    Baran, Derya

    2015-08-10

    Non-radiative recombination reduces the open-circuit voltage relative to its theoretical limit and leads to reduced luminescence emission at a given excitation. Therefore it is possible to correlate changes in luminescence emission with changes in open-circuit voltage and in the charge carrier lifetime. Here we use luminescence studies combined with transient photovoltage and differential charging analyses to study the effect of polymer fractionation in indacenoedithiophene-co-benzothiadiazole (IDTBT):fullerene solar cells. In this system, polymer fractionation increases electroluminescence and reduces non-radiative recombination. High molecular weight and fractionated IDTBT polymers exhibit higher carrier lifetime-mobility product compared to their non-fractionated analogues, resulting in improved solar cell performance.

  1. The Role of Polymer Fractionation in Energetic Losses and Charge Carrier Lifetimes of Polymer: Fullerene Solar Cells

    KAUST Repository

    Baran, Derya; Vezie, Michelle S; Gasparini, Nicola; Deledalle, Florent; Yao, Jizhong; Schroeder, Bob C.; Bronstein, Hugo; Ameri, Tayebeh; Kirchartz, Thomas; McCulloch, Iain; Nelson, Jenny; Brabec, Christoph J

    2015-01-01

    Non-radiative recombination reduces the open-circuit voltage relative to its theoretical limit and leads to reduced luminescence emission at a given excitation. Therefore it is possible to correlate changes in luminescence emission with changes in open-circuit voltage and in the charge carrier lifetime. Here we use luminescence studies combined with transient photovoltage and differential charging analyses to study the effect of polymer fractionation in indacenoedithiophene-co-benzothiadiazole (IDTBT):fullerene solar cells. In this system, polymer fractionation increases electroluminescence and reduces non-radiative recombination. High molecular weight and fractionated IDTBT polymers exhibit higher carrier lifetime-mobility product compared to their non-fractionated analogues, resulting in improved solar cell performance.

  2. Aqueous synthesis of highly luminescent glutathione-capped Mn{sup 2+}-doped ZnS quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Kolmykov, Oleksii [Université de Lorraine, Laboratoire Réactions et Génie des Procédés (LRGP), UMR 7274, CNRS, 1 rue Grandville, BP 20451, 54001 Nancy Cedex (France); Coulon, Joël [Université de Lorraine, Laboratoire de Chimie Physique et Microbiologie pour l' Environnement (LCPME), UMR 7564, CNRS, Faculté de Pharmacie, 5 rue Albert Lebrun, 54000 Nancy (France); Lalevée, Jacques [Institut de Science des Matériaux de Mulhouse (IS2M), UMR 7361, CNRS, 15 rue Jean Starcky, 68093 Mulhouse (France); Alem, Halima; Medjahdi, Ghouti [Université de Lorraine, Institut Jean Lamour (IJL), UMR 7198, CNRS, BP 70239, 54506 Vandoeuvre-lès-Nancy Cedex (France); Schneider, Raphaël, E-mail: raphael.schneider@univ-lorraine.fr [Université de Lorraine, Laboratoire Réactions et Génie des Procédés (LRGP), UMR 7274, CNRS, 1 rue Grandville, BP 20451, 54001 Nancy Cedex (France)

    2014-11-01

    In this paper, an aqueous-based route has been developed to prepare highly luminescent glutathione (GSH)-capped Mn-doped ZnS quantum dots (QDs). The dots obtained have an average diameter of 4.3 nm and exhibit the Mn{sup 2+}-related orange luminescence with very low surface defect density. The highest photoluminescence was observed for a Mn{sup 2+} to Zn{sup 2+} molar ratio of 3%. Consecutive overcoating of the Mn:ZnS@GSH QDs by a ZnS shell was done, and the core/shell structured QDs exhibit a PL quantum yield of 23%. Transmission electron microscopy, X-ray powder diffraction, electron spin resonance, X-ray photoelectron spectroscopy, UV–visible spectroscopy and spectrofluorometry have been used to characterize the crystal structure, the doping status, and the optical properties of the doped-QDs. Our systematic investigation shows that Mn:ZnS/ZnS@GSH QDs are highly promising fluorescent labels in biological applications.

  3. High Temperature Polymers for use in Fuel Cells

    Science.gov (United States)

    Peplowski, Katherine M.

    2004-01-01

    NASA Glenn Research Center (GRC) is currently working on polymers for fuel cell and lithium battery applications. The desire for more efficient, higher power density, and a lower environmental impact power sources has led to interest in proton exchanges membrane fuels cells (PEMFC) and lithium batteries. A PEMFC has many advantages as a power source. The fuel cell uses oxygen and hydrogen as reactants. The resulting products are electricity, heat, and water. The PEMFC consists of electrodes with a catalyst, and an electrolyte. The electrolyte is an ion-conducting polymer that transports protons from the anode to the cathode. Typically, a PEMFC is operated at a temperature of about 80 C. There is intense interest in developing a fuel cell membrane that can operate at higher temperatures in the range of 80 C- 120 C. Operating the he1 cell at higher temperatures increases the kinetics of the fuel cell reaction as well as decreasing the susceptibility of the catalyst to be poisoned by impurities. Currently, Nafion made by Dupont is the most widely used polymer membrane in PEMFC. Nafion does not function well above 80 C due to a significant decrease in the conductivity of the membrane from a loss of hydration. In addition to the loss of conductivity at high temperatures, the long term stability and relatively high cost of Nafion have stimulated many researches to find a substitute for Nafion. Lithium ion batteries are popular for use in portable electronic devices, such as laptop computers and mobile phones. The high power density of lithium batteries makes them ideal for the high power demand of today s advanced electronics. NASA is developing a solid polymer electrolyte that can be used for lithium batteries. Solid polymer electrolytes have many advantages over the current gel or liquid based systems that are used currently. Among these advantages are the potential for increased power density and design flexibility. Automobiles, computers, and cell phones require

  4. Multimode polymer waveguides for high-speed optical interconnects

    Science.gov (United States)

    Bamiedakis, N.; Ingham, J. D.; Penty, R. V.; White, I. H.; DeGroot, J. V.; Clapp, T. V.

    2017-11-01

    Polymeric multimode waveguides are of particular interest for optical interconnections in short-reach data links. In some applications, for example in space-borne systems, the use of advanced materials with outstanding performance in extreme environments is required (temperature and radiation). In this paper therefore, we present novel siloxane polymers suitable for these applications. The materials are used to form straight, 90° bent and spiral polymer waveguides by low-cost conventional photolithographic techniques on FR4 substrates. The samples have been tested to investigate their propagation characteristics and demonstrate their potential for high-speed data links. Overall, there is strong evidence that these multimode waveguides can be successfully employed as high-speed short-reach data links. Their excellent thermal properties, their low cost and the simple fabrication process indicate their suitability for a wide range of space applications.

  5. Luminescence enhancement of ZnO-poly(methylmethacrylate) nanocomposite films by incorporation of crystalline BaTiO{sub 3} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Kanamori, Tsuyoshi; Han, Yu; Nagao, Daisuke, E-mail: dnagao@tohoku.ac.jp; Kamezawa, Nao; Ishii, Haruyuki; Konno, Mikio

    2016-09-15

    Highlights: • Dielectric barium titanate (BT) nanoparticles incorporated into luminescence films. • Luminescence intensities increased by the BT nanoparticle incorporation. • Incorporation of highly dielectric nanoparticles effective for luminescence enhancement. - Abstract: Incorporation of highly dielectric nanoparticles into luminescent ZnO-polymethylmethacrylate (PMMA) nanocomposite films was undertaken to examine the effect of nanoparticle incorporation on luminescence intensity of the nanocomposite films. ZnO nanoparticles were prepared as inorganic phosphors by a precipitation method. The ZnO nanoparticles were then surface-modified with 3-methacryloxypropyltrimethoxysilane (MPTMS) to be used for fabrication of the ZnO-PMMA nanocomposite film. Barium titanate (BT) nanoparticles were synthesized with a sol-gel method as the highly dielectric nanoparticles, which were also surface-modified with the MPTMS for the incorporation into the nanocomposite films. Luminescence intensity of the nanocomposite films was successfully increased by the nanoparticle incorporation up to a BT content around 15 vol%. The luminescence intensity higher than that measured for the nanocomposite films incorporating SiO{sub 2} nanoparticles indicated that the incorporation of highly dielectric nanoparticles was an effective approach to enhance the luminescence of ZnO nanoparticles in the polymer thin films.

  6. High-quality uniform dry transfer of graphene to polymers.

    Science.gov (United States)

    Lock, Evgeniya H; Baraket, Mira; Laskoski, Matthew; Mulvaney, Shawn P; Lee, Woo K; Sheehan, Paul E; Hines, Daniel R; Robinson, Jeremy T; Tosado, Jacob; Fuhrer, Michael S; Hernández, Sandra C; Walton, Scott G

    2012-01-11

    In this paper we demonstrate high-quality, uniform dry transfer of graphene grown by chemical vapor deposition on copper foil to polystyrene. The dry transfer exploits an azide linker molecule to establish a covalent bond to graphene and to generate greater graphene-polymer adhesion compared to that of the graphene-metal foil. Thus, this transfer approach provides a novel alternative route for graphene transfer, which allows for the metal foils to be reused. © 2011 American Chemical Society

  7. Developing Flexible, High Performance Polymers with Self-Healing Capabilities

    Science.gov (United States)

    Jolley, Scott T.; Williams, Martha K.; Gibson, Tracy L.; Caraccio, Anne J.

    2011-01-01

    Flexible, high performance polymers such as polyimides are often employed in aerospace applications. They typically find uses in areas where improved physical characteristics such as fire resistance, long term thermal stability, and solvent resistance are required. It is anticipated that such polymers could find uses in future long duration exploration missions as well. Their use would be even more advantageous if self-healing capability or mechanisms could be incorporated into these polymers. Such innovative approaches are currently being studied at the NASA Kennedy Space Center for use in high performance wiring systems or inflatable and habitation structures. Self-healing or self-sealing capability would significantly reduce maintenance requirements, and increase the safety and reliability performance of the systems into which these polymers would be incorporated. Many unique challenges need to be overcome in order to incorporate a self-healing mechanism into flexible, high performance polymers. Significant research into the incorporation of a self-healing mechanism into structural composites has been carried out over the past decade by a number of groups, notable among them being the University of I1linois [I]. Various mechanisms for the introduction of self-healing have been investigated. Examples of these are: 1) Microcapsule-based healant delivery. 2) Vascular network delivery. 3) Damage induced triggering of latent substrate properties. Successful self-healing has been demonstrated in structural epoxy systems with almost complete reestablishment of composite strength being achieved through the use of microcapsulation technology. However, the incorporation of a self-healing mechanism into a system in which the material is flexible, or a thin film, is much more challenging. In the case of using microencapsulation, healant core content must be small enough to reside in films less than 0.1 millimeters thick, and must overcome significant capillary and surface

  8. Highly luminescent nanostructures of CdS and ZnS prepared by microwaves heating: effect of sulphide concentration

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz, Samuel; Gomez, Idalia; Elizondo, Perla [Facultad de Ciencias Quimicas, Universidad Autonoma de Nuevo Leon, Av. Universidad s/n, C.P. 66450 San Nicolas de los Garza (Mexico); Cavazos, Jose [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, Av. Universidad s/n, C.P. 66450 San Nicolas de los Garza (Mexico)

    2010-11-15

    Nearly monodisperse and highly luminescent ZnS and CdS NPs were obtained by microwave irradiation. The ZnS and CdS NPs solutions were prepared by adding freshly prepared ZnSO{sub 4} or CdSO{sub 4} solution to a thioacetamide solution at pH 8 in the presence of sodium citrate in solution used as stabilizer. The precursors concentration were such that the sulphide ion concentrations were 3 x 10{sup -2} M, 6 x 10{sup -2} M and 8 x 10{sup -2} M, for each of these [S] concentrations the [Zn] or [Cd] content were fixed at 3 x 10{sup -2} M. NPs were prepared under microwave irradiation for 1 min at 905 W of power. The NPs samples were taken when the temperature descended to ambient temperature for further analysis. Effect of concentration of Cd and Zn ions were studied in the luminescence property. RXD, AFM, TEM and UV-Vis were used too as analytical equipment for characterization. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  9. HCN Polymers: Toward Structure Comprehension Using High Resolution Mass Spectrometry

    Science.gov (United States)

    Bonnet, Jean-Yves; Thissen, Roland; Frisari, Ma; Vuitton, Veronique; Quirico, Eric; Le Roy, Léna; Fray, Nicolas; Cottin, Hervé; Horst, Sarah; Yelle, Roger

    A lot of solar system materials, including cometary ices and Titan aerosols, contain dark matter that can be interpreted as complex nitrogen bearing organic matter [1]. In laboratory experi-ments, HCN polymers are thus analogs of great interest. In fact they may be present in Titan atmosphere and in comet nuclei and then reprocessed as a CN distributed source [2], when ices began to sublimate and ejects from the nucleus organic matter grains [3]. The presence of HCN polymers is suggested because HCN molecule has been directly observed in 1P/Halley comet [4] and others. HCN polymers are also of prebiotic interest [5] as it can form amino acid under hydrolysis conditions. Even if they have been studied during the last decades, their chemical composition and structure are still poorly understood, and a great analytical effort has to be continued. In this way we present a high resolution mass spectrometry (HRMS) and a high resolution tandem mass spectrometry (MS/HRMS) analysis of HCN polymers. It was shown [6] that this is a suitable technique to elucidate composition and structure of the soluble part of tholins analogs of Titan's atmosphere aerosols. HCN polymers have never been studied by HRMS, thus we used a LTQ-Orbitrap XL high resolution mass spectrometer to analyse the HCN polymers. These are produced at LISA by direct polymerisation of pure liquid HCN, catalyzed by ammonia. HCN polymers have been completely dissolved in methanol and then injected in the mass spectrometer by ElectroSpray Ionization (ESI). This atmospheric pressure ionization process produces protonated or deprotonated ions, but it does not fragment molecules. Thus HRMS, allows a direct access to the stoechiometry of all the ionizable molecules present in the samples. Fragmentation analyses (MS/MS) of selected ions have also been performed. Thess analysis provide information about the different chemical fonctionnalities present in HCN poly-mers and also about their structure. Thus we are able to

  10. Conducting polymer nanowire arrays for high performance supercapacitors.

    Science.gov (United States)

    Wang, Kai; Wu, Haiping; Meng, Yuena; Wei, Zhixiang

    2014-01-15

    This Review provides a brief summary of the most recent research developments in the fabrication and application of one-dimensional ordered conducting polymers nanostructure (especially nanowire arrays) and their composites as electrodes for supercapacitors. By controlling the nucleation and growth process of polymerization, aligned conducting polymer nanowire arrays and their composites with nano-carbon materials can be prepared by employing in situ chemical polymerization or electrochemical polymerization without a template. This kind of nanostructure (such as polypyrrole and polyaniline nanowire arrays) possesses high capacitance, superior rate capability ascribed to large electrochemical surface, and an optimal ion diffusion path in the ordered nanowire structure, which is proved to be an ideal electrode material for high performance supercapacitors. Furthermore, flexible, micro-scale, threadlike, and multifunctional supercapacitors are introduced based on conducting polyaniline nanowire arrays and their composites. These prototypes of supercapacitors utilize the high flexibility, good processability, and large capacitance of conducting polymers, which efficiently extend the usage of supercapacitors in various situations, and even for a complicated integration system of different electronic devices. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. luminescence properties

    Indian Academy of Sciences (India)

    1Faculty of Science and Arts, Department of Chemistry, Bozok University, Yozgat 66900, Turkey. 2Faculty of Science, Department of Chemistry, Erciyes ... synthesized by the conventional solid-state reaction method, their crystal structures and luminescence properties were investigated. X-ray diffraction patterns (XRD) ...

  12. Direct dimethyl ether high temperature polymer electrolyte membrane fuel cells

    DEFF Research Database (Denmark)

    Vassiliev, Anton; Jensen, Jens Oluf; Li, Qingfeng

    and suffers from low DME solubility in water. When the DME - water mixture is fed as vapour miscibility is no longer a problem. The increased temperature is more beneficial for the kinetics of the direct oxidation of DME than of methanol. The Open Circuit Voltage (OCV) with DME operation was 50 to 100 m......A high temperature polybenzimidazole (PBI) polymer fuel cell was fed with dimethyl ether (DME) and water vapour mixture on the anode at ambient pressure with air as oxidant. A peak power density of 79 mW/cm2 was achieved at 200°C. A conventional polymer based direct DME fuel cell is liquid fed......V higher than that of methanol, indicating less fuel crossover....

  13. High-photovoltage all-polymer solar cells based on a diketopyrrolopyrrole-isoindigo acceptor polymer

    NARCIS (Netherlands)

    Li, Z.; Xu, X.; Zhang, W.; Genene, Z.; Mammo, W.; Yartsev, A.; Andersson, M.R.; Janssen, R.A.J.; Wang, E.

    2017-01-01

    In this work, we synthesized and characterized two new n-type polymers PTDPP-PyDPP and PIID-PyDPP. The former polymer is composed of pyridine-flanked diketopyrrolopyrrole (PyDPP) and thiophene-flanked diketopyrrolopyrrole (TDPP). The latter polymer consists of PyDPP and isoindigo (IID). PIID-PyDPP

  14. Searching for Models Exhibiting High Circularly Polarized Luminescence: the Electroactive Inherently Chiral Oligothiophenes.

    Science.gov (United States)

    Benincori, Tiziana; Appoloni, Giulio; Mussini, Patrizia Romana; Arnaboldi, Serena; Cirilli, Roberto; Quartapelle Procopio, Elsa; Panigati, Monica; Abbate, Sergio; Mazzeo, Giuseppe; Longhi, Giovanna

    2018-05-02

    Two new inherently chiral oligothiophenes characterized by the atropisomeric 3,3'-bithianaphtene scaffold functionalized with fused ring bithiophene derivatives, namely 4H-cyclopenta [2,1-b3:4b']dithiophene (CPDT) and dithieno[3,3-b:2',3'-d]pyrrole (DTP), were synthesized. The racemates were fully characterized and resolved into antipodes by enantioselective HPLC. The enantiomers were analyzed through different chiroptical techniques: electronic circular dichroism (ECD) and vibrational circular dichroism (VCD) were employed to attribute the absolute configuration (AC). Comparison of experimental and calculated VCD spectra confirmed the DFT calculated conformational characteristics. The compound functionalized with two CPDT units was oxidized with FeCl3 and ECD and CPL of the resulting material were measured. Circularly Polarized Luminescence (CPL) was measured in order to verify if inherently chiral oligothiophenes could be promising systems for chiral photonics applications. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Highly Enhanced Raman Scattering on Carbonized Polymer Films.

    Science.gov (United States)

    Yoon, Jong-Chul; Hwang, Jongha; Thiyagarajan, Pradheep; Ruoff, Rodney S; Jang, Ji-Hyun

    2017-06-28

    We have discovered a carbonized polymer film to be a reliable and durable carbon-based substrate for carbon enhanced Raman scattering (CERS). Commercially available SU8 was spin coated and carbonized (c-SU8) to yield a film optimized to have a favorable Fermi level position for efficient charge transfer, which results in a significant Raman scattering enhancement under mild measurement conditions. A highly sensitive CERS (detection limit of 10 -8 M) that was uniform over a large area was achieved on a patterned c-SU8 film and the Raman signal intensity has remained constant for 2 years. This approach works not only for the CMOS-compatible c-SU8 film but for any carbonized film with the correct composition and Fermi level, as demonstrated with carbonized-PVA (poly(vinyl alcohol)) and carbonized-PVP (polyvinylpyrollidone) films. Our study certainly expands the rather narrow range of Raman-active material platforms to include robust carbon-based films readily obtained from polymer precursors. As it uses broadly applicable and cheap polymers, it could offer great advantages in the development of practical devices for chemical/bio analysis and sensors.

  16. Plasmon-enhanced luminescence of Sm complex using silver nanoparticles in Polyvinyl Alcohol

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Gagandeep; Verma, R.K.; Rai, D.K. [Laser and Spectroscopy Laboratory, Department of Physics, Banaras Hindu University, India 221005 (India); Rai, S.B., E-mail: sbrai49@yahoo.co.in [Laser and Spectroscopy Laboratory, Department of Physics, Banaras Hindu University, India 221005 (India)

    2012-07-15

    Silver (Ag) nanoparticles (NPs) were prepared by laser ablation in water with an aim to enhance the luminescence of rare earth coordinated complex in polymer host. A fixed concentration of the complex containing Samarium (Sm), Salicylic acid (Sal) and 1, 10-phenanthroline (Phen) were combined with different concentrations of silver NPs in PolyVinyl Alcohol at room temperature. Absorption spectrum and XRD patterns of the sample show that the Sm(Sal){sub 3}Phen complex is accompanied by Ag NPs. The luminescence from the complex was recorded in the presence and absence of Ag NPs using two different excitation wavelengths viz. 400 and 355 nm. Of these, 400 nm radiation falls in the surface plasmon resonance of Ag NPs. It was found that the Ag NPs led to a significant enhancement in luminescence of the complex. Surprisingly, a high concentration of Ag NPs tends to quench the luminescence. - Highlights: Black-Right-Pointing-Pointer Sm complex with Ag nanoparticles in PVA was prepared at room temperature. Black-Right-Pointing-Pointer UV-vis absorption and XRD confirms the presence of Sm complex and Ag NPs. Black-Right-Pointing-Pointer Enhancement in luminescence of complex was observed with Ag NPs. Black-Right-Pointing-Pointer Coupling between radiative transitions of Sm and SPR of NPs enhances the emission. Black-Right-Pointing-Pointer The higher concentration of Ag NPs quenches the luminescence of the complex.

  17. Highly flexible and all-solid-state paperlike polymer supercapacitors.

    Science.gov (United States)

    Meng, Chuizhou; Liu, Changhong; Chen, Luzhuo; Hu, Chunhua; Fan, Shoushan

    2010-10-13

    In recent years, much effort have been dedicated to achieve thin, lightweight and even flexible energy-storage devices for wearable electronics. Here we demonstrate a novel kind of ultrathin all-solid-state supercapacitor configuration with an extremely simple process using two slightly separated polyaniline-based electrodes well solidified in the H(2)SO(4)-polyvinyl alcohol gel electrolyte. The thickness of the entire device is much comparable to that of a piece of commercial standard A4 print paper. Under its highly flexible (twisting) state, the integrate device shows a high specific capacitance of 350 F/g for the electrode materials, well cycle stability after 1000 cycles and a leakage current of as small as 17.2 μA. Furthermore, due to its polymer-based component structure, it has a specific capacitance of as high as 31.4 F/g for the entire device, which is more than 6 times that of current high-level commercial supercapacitor products. These highly flexible and all-solid-state paperlike polymer supercapacitors may bring new design opportunities of device configuration for energy-storage devices in the future wearable electronic area.

  18. High pressure synthesis of zeolite/polymer nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Haines, Julien; Thibaud, Jean-Marc; Rouquette, Jerome; Cambon, Olivier; Di Renzo, Francesco, E-mail: julien.haines@univ-montp2.fr [Institut Charles Gerhardt Montpellier (France); Lee, Arie van der [Institut Europeen des Membranes, Montpellier (France); Scelta, Demetrio; Ceppatelli, Matteo; Dziubek, Kamil; Gorelli, Federico; Bini, Roberto; Santoro, Mario [European Laboratory for Non Linear Spectroscopy, Firenze (Italy)

    2016-07-01

    Full text: Polymerization of simple organic molecules under high pressure in the subnanometric pores of pure SiO{sub 2} zeolites can be used to produce novel nanocomposite materials, which can be recovered at ambient P and have remarkable mechanical, electrical or optical properties. Polymerization of ethylene in silicalite was studied in situ at high pressure by IR and results in a nanocomposite with isolated chains of non-conducting polyethylene strongly confined in the pores based on single crystal x-ray diffraction data. The nanocomposite is much less compressible than silicalite and has a positive rather than a negative thermal expansion coefficient. In order to target novel electrical and optical properties, isolated chains of conducting polymers can also be prepared in the pores of zeolite hosts at high pressure, such as polyacetylene, which was polymerized under pressure in the pores of the 1-D zeolite TON. The structure of this nanocomposite was determined by synchrotron x-ray powder diffraction data with complete pore filling corresponding to one planar polymer chain confined in each pore with a zig-zag configuration in the yz plane. This very strong confinement can be expected to strongly modify the electrical properties of polyacetylene. In this nanocomposite, our theoretical calculations indicate that the electronic density of states of polyacetylene exhibit van Hove singularities related to quantum 1D confinement, which could lead to future technological applications. This new material is susceptible to have applications in nanoelectronics, nanophotonics and energy and light harvesting. Completely novel nanocomposites were prepared by the polymerization of carbon monoxide CO in silicalite and TON. In these materials, isolated, ideal polycarbonyl chains are obtained in contrast to the non-stoichiometric, branched bulk polymers obtained by high pressure polymerization of this simple system. These poly CO/zeolite composites could be interesting energetic

  19. Highly luminescent InP/GaP/ZnS nanocrystals and their application to white light-emitting diodes.

    Science.gov (United States)

    Kim, Sungwoo; Kim, Taehoon; Kang, Meejae; Kwak, Seong Kwon; Yoo, Tae Wook; Park, Lee Soon; Yang, Ilseung; Hwang, Sunjin; Lee, Jung Eun; Kim, Seong Keun; Kim, Sang-Wook

    2012-02-29

    Highly stable and luminescent InP/GaP/ZnS QDs with a maximum quantum yield of 85% were synthesized by in situ method. The GaP shell rendered passivation of the surface and removed the traps. TCSPC data showed an evidence for the GaP shell. InP/GaP/ZnS QDs show better stability than InP/ZnS. We studied the optical properties of white QD-LEDs corresponding to various QD concentrations. Among various concentrations, the white QD-LEDs with 0.5 mL of QDs exhibited a luminous efficiency of 54.71 lm/W, Ra of 80.56, and CCT of 7864 K. © 2012 American Chemical Society

  20. High-Voltage Polymers for High-Power Supercapacitors. Version 1

    Science.gov (United States)

    2006-05-30

    affect the supercapacitor’s performance. Subsequently, our efforts focused on fabricating polymers with high oxidation potentials to increase the power...including spin activation with out significant modifications. Electroactive polymers such as polythiophene, polyacetylene, or polyaniline can be...potentials in excess of 2 V for facile polymerization. In the present case, the triaryl ammine functionality of 2 and 3 is oxidized at the low

  1. Luminescent polymethyl methacrylate modified by gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Morais, Guilherme F. [Faculdade de Tecnologia de Sao Paulo (FATEC-ZL), Sao Paulo, SP (Brazil); Forster, Pedro L.; Marchini, Leonardo G.; Lugao, Ademar B.; Parra, Duclerc F., E-mail: dfparra@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    Thin films of PMMA (polymethyl methacrylate) doped with luminescent complexes have been studied and developed for applications in advanced technologies. The problem of stability of these films is focused in this study. Films stabilization by reaction with fluorinated monomers is a recent study that aims to increase its luminescence properties for long time. The films were prepared by dilution of PMMA in chloroform with addition of europium complex, at proportion of 5% by weight of polymer. The luminescent polymer films were obtained by casting. Thin layer slides of the film were separated in three parts. One was reacted with fluorinated monomers (C{sub 2}F{sub 4}) in closed reactor for 48 hours. A second part was reacted with C{sub 2}F{sub 4} after irradiation in gamma source at 5 kGy in simultaneous process. The last part was used as obtained. The luminescent polymer matrices were characterized using the techniques of infrared (FTIR) and thermogravimetry (TGA/DTG). Samples of the films were, in presence of fluorine monomers, exposed to ionizing radiation in dose of 5 kGy, for react with monomers in the doped polymer surface. In this case the effects of radiation were evaluated on the luminescent films. (author)

  2. Luminescent polymethyl methacrylate modified by gamma radiation

    International Nuclear Information System (INIS)

    Morais, Guilherme F.; Forster, Pedro L.; Marchini, Leonardo G.; Lugao, Ademar B.; Parra, Duclerc F.

    2011-01-01

    Thin films of PMMA (polymethyl methacrylate) doped with luminescent complexes have been studied and developed for applications in advanced technologies. The problem of stability of these films is focused in this study. Films stabilization by reaction with fluorinated monomers is a recent study that aims to increase its luminescence properties for long time. The films were prepared by dilution of PMMA in chloroform with addition of europium complex, at proportion of 5% by weight of polymer. The luminescent polymer films were obtained by casting. Thin layer slides of the film were separated in three parts. One was reacted with fluorinated monomers (C 2 F 4 ) in closed reactor for 48 hours. A second part was reacted with C 2 F 4 after irradiation in gamma source at 5 kGy in simultaneous process. The last part was used as obtained. The luminescent polymer matrices were characterized using the techniques of infrared (FTIR) and thermogravimetry (TGA/DTG). Samples of the films were, in presence of fluorine monomers, exposed to ionizing radiation in dose of 5 kGy, for react with monomers in the doped polymer surface. In this case the effects of radiation were evaluated on the luminescent films. (author)

  3. Syntheses, crystal structures and luminescent properties of two new 1D d 1 coordination polymers constructed from 2,2'-bibenzimidazole and 1,4-benzenedicarboxylate

    International Nuclear Information System (INIS)

    Wen Lili; Li Yizhi; Dang Dongbin; Tian Zhengfang; Ni Zhaoping; Meng Qingjin

    2005-01-01

    Two novel interesting d 1 metal coordination polymers, [Zn(H 2 bibzim)(BDC)] n (1) and [Cd(H 2 bibzim)(BDC)] n (2) [H 2 bibzim=2,2'-bibenzimidazole, BDC=1,4-benzenedicarboxylate] have been synthesized under solvothermal conditions and structurally characterized. Both 1 and 2 are constructed from infinite neutral zigzag-like one-dimensional (1D) chains. The π-π interactions and interchain hydrogen-bonding interactions further extend the 1D arrangement to generate a 3D supramolecular architecture for 1 and 2. Both complexes have high thermal stability and display strong blue fluorescent emissions in the solid state upon photo-excitation at 365 nm at room temperature. They are the first two examples that 2,2'-bibenzimidazole has been introduced into the d 1 coordination polymeric framework

  4. High-Voltage Solid Polymer Batteries for Electric Drive Vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Eitouni, Hany; Yang, Jin; Pratt, Russell; Wang, Xiao; Grape, Ulrik

    2014-09-29

    The purpose of this project was for Seeo to develop a high energy lithium based technology with targets of over 500 Wh/l and 325 Wh/kg. Seeo would leverage the work already achieved with its unique proprietary solid polymer DryLyteTM technology in cells which had a specific energy density of 220 Wh/kg. The development work was focused on establishing a dual electrolyte system, coated cathode particle techniques, various types of additives, and different conductive salts. The program had a duration of three years, with Seeo delivering the final cells at the end of 2014 for evaluation by a DOE laboratory.

  5. Nonlinear transport in semiconducting polymers at high carrier densities.

    Science.gov (United States)

    Yuen, Jonathan D; Menon, Reghu; Coates, Nelson E; Namdas, Ebinazar B; Cho, Shinuk; Hannahs, Scott T; Moses, Daniel; Heeger, Alan J

    2009-07-01

    Conducting and semiconducting polymers are important materials in the development of printed, flexible, large-area electronics such as flat-panel displays and photovoltaic cells. There has been rapid progress in developing conjugated polymers with high transport mobility required for high-performance field-effect transistors (FETs), beginning with mobilities around 10(-4) cm(2) V(-1) s(-1) to a recent report of 1 cm(2) V(-1) s(-1) for poly(2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2-b]thiophene) (PBTTT). Here, the electrical properties of PBTTT are studied at high charge densities both as the semiconductor layer in FETs and in electrochemically doped films to determine the transport mechanism. We show that data obtained using a wide range of parameters (temperature, gate-induced carrier density, source-drain voltage and doping level) scale onto the universal curve predicted for transport in the Luttinger liquid description of the one-dimensional 'metal'.

  6. High-throughput synthesis equipment applied to polymer research

    NARCIS (Netherlands)

    Hoogenboom, R.; Schubert, U.S.

    2005-01-01

    To speed up synthetic polymer research, a workflow dedicated to automated polymer synthesis and characterization was developed. The workflow consists of several synthesis robots with online and offline analytical equipment. For screening of reaction parameters and for library synthesis, robots

  7. Electro-optic polymers for high speed modulators

    NARCIS (Netherlands)

    Balakrishnan, M.; Diemeer, Mart; Driessen, A.; Faccini, M.; Verboom, Willem; Reinhoudt, David; Leinse, Arne; Megret, P.; Wuilpart, M.; Bette, S.; Staquet, N.

    2005-01-01

    Different electro-optic polymer systems are analyzed with respect to their electro-optic activity, glass transition temperature $(T_g)$ and photodefinable properties. The polymers tested are polysulfone (PS) and polycarbonate (PC). The electro-optic chromophore,

  8. Mineralizer-assisted high-pressure high-temperature synthesis and characterization of novel phosphorus nitride imides and luminescent alkaline earth metal (oxo)nitridophosphates

    International Nuclear Information System (INIS)

    Marchuk, Alexey

    2016-01-01

    The main objectives of this thesis were the synthesis, identification and structural characterization of new alkaline earth metal (oxo)nitridophopshates and phosphorus nitrides. Furthermore, luminescence properties of the resulting materials should be investigated and a connection between these properties and the respective structures should be established. For this purpose, a range of synthesis strategies was employed, including conventional solid-state syntheses in silica ampoules and high-pressure high-temperature syntheses using the multianvil technique. The emphasis of the synthetic part of this thesis lies on the development of new synthetic strategies in order to increase crystallinity of alkaline earth metal (oxo)nitridophosphates and thus accelerate their structure determination. This involves the selection of a suitable mineralizer and the investigation of its interaction with the respective starting materials. In addition, the analytical methods applied in this thesis in order to identify and characterize the compounds are just as essential as the synthesis strategies. X-ray diffraction on single crystals and on powders was carried out as the main analytical method while being supported by quantitative and qualitative 1 H and 31 P solid-state NMR measurements, FTIR and energy-dispersive X-ray (EDX) spectroscopy, as well as electron microscopy methods including both imaging and diffraction techniques. Implied by the large number of novel structures investigated, theoretical studies including topological analysis, calculations of lattice energies and bond-valence sums also played a major role in this thesis. Optical analysis methods such as reflectance spectroscopy, luminescence microscopy and photoluminescence measurements helped to determine the luminescence properties of some of the presented compounds.

  9. Electric breakdown of high polymer insulating materials at cryogenic temperature

    International Nuclear Information System (INIS)

    Kim, Sanhyon; Yoshino, Katsumi

    1985-01-01

    Cryogenic properties : temperature dependence of E sub(b) and effects of media upon E sub(b) were investigated on several high polymers. Temperature conditions were provided by liquid He (4.2 K), liquid N 2 (77 K) and cryogen (dry ice-methyl alcohol, 194 K). Silicone oil was used also at ambient temperature and elevated temperature. Polymer film coated with gold by vacuum evaporation was placed in cryostat, and high tension from pulse generator was applied to the film. Dielectric breakdowns were detected by oscilloscope and observed visually. The results of experiment are summerized as follow. (1) E sub(b) of film in He is affected by medium remarkably, and covering with 3-methyl pentane is effective for increasing E sub(b). (2) Temperature dependence of E sub(b) was not recognized in cryogenic temperature below liquid N 2 . (3) Temperature characteristic of E sub(b) changes considerably at the critical temperature T sub(c), and T sub(c) is dependent on material. (4) Strength against dielectric breakdown under cryogenic temperature is not affected by bridging caused by irradiation of electron beam. (5) Dielectric breakdown is thought to be caused by electronic process such as electron avalanche. Consequently, for designing insulation for the temperature below liquid He, insulation design for liquid N 2 is thought to be sufficient. However, the degradation and breakdown by mechanical stress under cryogenic temperature must be taken into consideration. (Ishimitsu, A.)

  10. Detection of Waterborne Viruses Using High Affinity Molecularly Imprinted Polymers.

    Science.gov (United States)

    Altintas, Zeynep; Gittens, Micah; Guerreiro, Antonio; Thompson, Katy-Anne; Walker, Jimmy; Piletsky, Sergey; Tothill, Ibtisam E

    2015-07-07

    Molecularly imprinted polymers (MIPs) are artificial receptor ligands which can recognize and specifically bind to a target molecule. They are more resistant to chemical and biological damage and inactivation than antibodies. Therefore, target specific-MIP nanoparticles are aimed to develop and implemented to biosensors for the detection of biological toxic agents such as viruses, bacteria, and fungi toxins that cause many diseases and death due to the environmental contamination. For the first time, a molecularly imprinted polymer (MIP) targeting the bacteriophage MS2 as the template was investigated using a novel solid-phase synthesis method to obtain the artificial affinity ligand for the detection and removal of waterborne viruses through optical-based sensors. A high affinity between the artificial ligand and the target was found, and a regenerative MIP-based virus detection assay was successfully developed using a new surface plasmon resonance (SPR)-biosensor which provides an alternative technology for the specific detection and removal of waterborne viruses that lead to high disease and death rates all over the world.

  11. High Rate Micromechanical Behavior of Grafted Polymer Nanoparticle Films

    Science.gov (United States)

    Thomas, Edwin

    We report the ultra high strain rate behavior of films comprised of polymer grafted nanoparticles (NPs) and compare the results to homopolymer films. The films are formed by flow coating a suspension of polystyrene (PS) chains of 230 kg/mol grafted to 16nm diameter SiO2\\ at a graft density of 0.6 chains/nm2 resulting a film with 1 vol % SiO2. Films of 267 kg/mol PS were also flow coated and both films were impacted at velocities 350-700 ms-1 using 3.7 micron SiO2\\ projectiles to achieve increments in kinetic energy (KE) of 1:2:4. The KE of the projectiles before and after penetration was measured to determine the penetration energy. TEM and SEM suggest the projectile initially induces plastic flow due to the adiabatic temperature rise from impact. As the projectile deforms the film, the lower magnitude, biaxial stress state in the peripherial regions causes material microvoid formation and initiation of craze growth in the radial and tangential directions. The anchoring of the grafted polymer chains to the NPs increases the penetration energy relative to the pure homopolymer by 50% and the films capacity to delocalize the impact by 200%. These results suggest that highly grafted NP films may be useful in lightweight protection systems. In collaboration with Omri Fried, Olawale Lawal, Yang Jiao, Victor Hsaio, Thevamaran Ramathasan, Mujin Zhou, Richard Vaia.

  12. Polybenzimidazoles based on high temperature polymer electrolyte fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Linares Leon, Jose Joaquin; Camargo, Ana Paula M.; Ashino, Natalia M.; Morgado, Daniella L.; Frollini, Elisabeth; Paganin, Valdecir A.; Gonzalez, Ernesto Rafael [Universidade de Sao Paulo (IQSC/USP), Sao Carlos, SP (Brazil); Bajo, Justo Lobato [University of Castilla-La Mancha, Ciudad Real (Spain). Dept. of Chemical Engineering

    2010-07-01

    This work presents an interesting approach in order to enhance the performance of Polymer Electrolyte Membrane Fuel Cells (PEMFC) by means of an increase in the operational temperature. For this, two polymeric materials, Poly(2,5-bibenzimidazole) (ABPBI) and Poly[2,2'-(m-phenyl en)-5,5' bib enzimidazol] (PBI), impregnated with phosphoric acid have been utilized. These have shown excellent properties, such as thermal stability above 500 deg C, reasonably high conductivity when impregnated with H{sub 3}PO{sub 4} and a low permeability to alcohols compared to Nafion. Preliminary fuel cells measurements on hydrogen based Polymer Electrolyte Membrane Fuel Cell (PEMFC) displayed an interestingly reasonable good fuel cell performance, a quite reduced loss when the hydrogen stream was polluted with carbon monoxide, and finally, when the system was tested with an ethanol/water (E/W) fuel, it displayed quite promising results that allows placing this system as an attractive option in order to increase the cell performance and deal with the typical limitations of low temperature Nafion-based PEMFC. (author)

  13. Five new Zn(II) and Cd(II) coordination polymers constructed by 3,5-bis-oxyacetate-benzoic acid: Syntheses, crystal structures, network topologies and luminescent properties

    International Nuclear Information System (INIS)

    Jiang Xianrong; Yuan Hongyan; Feng Yunlong

    2012-01-01

    Five Zn(II) and Cd(II) coordination polymers, [Zn 2 (BOABA)(bpp)(OH)]·0.5H 2 O (1), [Cd 3 (BOABA) 2 (bpp) 2 (H 2 O) 6 ]·2H 2 O (2), [Cd 3 (BOABA) 2 (2,2′-bipy) 3 (H 2 O) 4 ]·5.5H 2 O (3), [CdNa(BOABA)(H 2 O)] 2 ·H 2 O (4) and [Cd 2 (BOABA)(bimb)Cl(H 2 O) 2 ]·H 2 O (5) (H 3 BOABA=3,5-bis-oxyacetate-benzoic acid, bpp=1,3-bi(4-pyridyl)propane, 2,2′-bipy=2,2′-bipyridine, bimb=1,4-bis(imidazol-1′-yl)butane), have been solvothermally synthesized and characterized by single-crystal X-ray diffraction, elemental analyses, IR spectra and TG analyses. 1 is an uninodal 4-connected 2D square grid network based on binuclear zinc clusters. 2 is 2D wavelike layer structure and further linked by hydrogen bonds into the final 3D (5,6,6)-connected topology network. 3 is 3-connected 2D topology network and the 2,2′-bipy ligands decorate in two different types. 4 is a (4,8)-connected 2D topology network with heterocaryotic {Cd 2 Na 2 } clusters and BOABA 3– ligands. 5 can be rationalized as a (3,10)-connected 3D topology network with tetranuclear {Cd 4 Cl 2 } clusters and BOABA 3– ligands. Meanwhile, photoluminescence studies revealed that these five coordination polymers display strong fluorescent emission bands in the solid state at room temperature. - Graphical abstract: Five new d 10 metal(II) coordination polymers based on H 3 BOABA ligand were obtained and characterized. They display different topological structures and luminescent properties. Highlights: ► Five d 10 metal(II) polymers based on 3,5-bis-oxyacetate-benzoic acid were obtained. ► The polymers were structurally characterized by single-crystal X-ray diffraction. ► Polymers 1–5 display different topological structures. ► They show strong fluorescent emission bands in the solid state.

  14. Transparent CuInS2/PMMA nanocomposites luminescent in the visible and NIR region

    International Nuclear Information System (INIS)

    Gugula, Krzysztof; Bredol, Michael

    2014-01-01

    Nanocomposites combining functional nanoparticles and transparent polymers allow for stabilization of filler properties over long periods of time while retaining transparency of the polymer matrix. Here we employ CuInS 2 /ZnS quantum dots (QDs), ternary visible- and NIR-emitting semiconductors as wavelength-tunable luminescent fillers. Luminescence in the near infrared (NIR) is of particular interest in medicine which allows deep penetration into human tissue enabling in vivo diagnostics and treatment, while visible emitters may serve as color converters in displays or lighting. To stabilize the optical properties of QDs and prevent agglomeration, polymethyl metacrylate (PMMA) was chosen as a matrix. These novel polymer nanocomposites (PNCs) show good optical properties and stability under ambient conditions, and can be easily deposited over large areas. High-quality QDs and hydrophobic functionalization with long-chain hydrocarbons are a prerequisite for embedding into a PMMA matrix. Transparent PNC films without visible scattering losses were obtained for 1 wt-% QD loading with respect to the polymer. Partial transparency is retained up to 10 wt-% QD loading and vanishes rapidly at higher loading. Luminescence properties increase up to 5 wt-% and then decrease rapidly due to QD agglomeration and reabsorption between adjacent particles. Potential applications include converter materials for medical applications, laser layers, displays and white LEDs. (orig.)

  15. Luminescence of Tb.sup.3+./sup.-doped high silica glass under UV and X-ray excitation

    Czech Academy of Sciences Publication Activity Database

    Chewpraditkul, W.; Shen, Y.; Chen, D.; Beitlerová, Alena; Nikl, Martin

    2013-01-01

    Roč. 35, č. 3 (2013), s. 426-430 ISSN 0925-3467 R&D Projects: GA MŠk LH12185 Institutional support: RVO:68378271 Keywords : Tb 3+ * luminescence * luminescence decays * porous silica glass * scintillation Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.075, year: 2013 http://dx.doi.org/10.1016/j.optmat.2012.09.012

  16. High-Performance All-Polymer Solar Cells Achieved by Fused Perylenediimide-Based Conjugated Polymer Acceptors.

    Science.gov (United States)

    Yin, Yuli; Yang, Jing; Guo, Fengyun; Zhou, Erjun; Zhao, Liancheng; Zhang, Yong

    2018-05-09

    We report three n-type polymeric electron acceptors (PFPDI-TT, PFPDI-T, and PFPDI-Se) based on the fused perylene diimide (FPDI) and thieno[3,2- b]thiophene, thiophene, or selenophene units for all-polymer solar cells (all-PSCs). These FPDI-based polymer acceptors exhibit strong absorption between 350 and 650 nm with wide optical bandgap of 1.86-1.91 eV, showing good absorption compensation with the narrow bandgap polymer donor. The lowest unoccupied molecular orbital (LUMO) energy levels were located at around -4.11 eV, which are comparable with those of the fullerene derivatives and other small molecular electron acceptors. The conventional all-PSCs based on the three polymer acceptors and PTB7-Th as polymer donor gave remarkable power conversion efficiencies (PCEs) of >6%, and the PFPDI-Se-based all-PSC achieved the highest PCE of 6.58% with a short-circuit current density ( J sc ) of 13.96 mA/cm 2 , an open-circuit voltage ( V oc ) of 0.76 V, and a fill factor (FF) of 62.0%. More interestingly, our results indicate that the photovoltaic performances of the FPDI-based polymer acceptors are mainly determined by the FPDI unit with a small effect from the comonomers, which is quite different from the others reported rylenediimide-based polymer acceptors. This intriguing phenomenon is speculated as the huge geometry configuration of the FPDI unit, which minimizes the effect of the comonomer. These results highlight a promising future for the application of the FPDI-based polymer acceptors in the highly efficient all-PSCs.

  17. High luminescent fibers with hybrid SiO2-coated CdTe nanocrystals fabricated by electrospinning technique

    International Nuclear Information System (INIS)

    Cao, Yongqiang; Liu, Ning; Yang, Ping; Shi, Ruixia; Ma, Qian; Zhang, Aiyu; Zhu, Yuanna; Wang, Junpeng; Wang, Jianrong

    2015-01-01

    The polyvinylpyrrolidone (PVP) hybrid luminescent micro-/nanofibers doped with the novel hybrid SiO 2 -coated CdTe nanocrystals (HS-CdTe NCs) have been fabricated for the first time via the electrospinning technique. The morphologies and photoluminescence (PL) emissions of HS-CdTe/PVP micro-/nanofibers prepared by doping the HS-CdTe NCs with the different PL peak wavelength (571, 616, and 643 nm) in PVP fibers were investigated by optical and PL microscope. The results revealed that all the HS-CdTe/PVP hybrid fibers showed an ultralong length for several hundreds of micrometers and a relatively uniform diameter of 1000 ∼ 1200 nm. The hybrid fibers displayed a wavelength-tunable PL emission, determining by the PL of doped HS-CdTe NCs. Moreover, similar to the original PL properties of HS-CdTe NCs before the electrospinning, the HS-CdTe/PVP fibers also showed a series of superior PL properties, such as narrow and symmetry PL spectrum, high, and uniform brightness. For comparison purpose, we also prepared three CdTe/PVP hybrid fibers by doping the 553 nm, 600 nm, and 633 nm PL-emitting CdTe NCs respectively in PVP electrospinning fibers. The characterization results showed that, the obtained three CdTe/PVP hybrid fibers had a basically satisfactory micro-/nanofiber morphology with a long length and relatively uniform diameter, but all the fibers exhibited very weak PL emissions. The enormous contrast in PL properties between HS-CdTe/PVP and CdTe/PVP fibers should mainly be ascribed to the different connection modes of ligands with the NCs and the passivation effect of inert hybrid silica shell on HS-CdTe. It is hopeful that the high luminescent HS-CdTe/PVP micro-/nanofibers with the tunable PL peak wavelength would be a good candidate in the optical sensor, light-emitting devices (LEDs), nanometer-scale waveguides, and the other related photonic materials. - Highlights: • The HS-CdTe/PVP electrospun hybrid fibers were fabricated for the first time. • The

  18. Material for a luminescent solar concentrator

    Science.gov (United States)

    Andrews, L.J.

    1984-01-01

    A material for use in a luminescent solar concentrator, formed by ceramitizing the luminescent ion Cr/sup 3 +/ with a transparent ceramic glass containing mullite. The resultant material has tiny Cr/sup 3 +/-bearing crystallites dispersed uniformly through an amorphous glass. The invention combines the high luminescent efficiency of Cr/sup 3 +/ in the crystalline phase with the practical and economical advantages of glass technology.

  19. Highly Luminescent Phase-Stable CsPbI3 Perovskite Quantum Dots Achieving Near 100% Absolute Photoluminescence Quantum Yield.

    Science.gov (United States)

    Liu, Feng; Zhang, Yaohong; Ding, Chao; Kobayashi, Syuusuke; Izuishi, Takuya; Nakazawa, Naoki; Toyoda, Taro; Ohta, Tsuyoshi; Hayase, Shuzi; Minemoto, Takashi; Yoshino, Kenji; Dai, Songyuan; Shen, Qing

    2017-10-24

    Perovskite quantum dots (QDs) as a new type of colloidal nanocrystals have gained significant attention for both fundamental research and commercial applications owing to their appealing optoelectronic properties and excellent chemical processability. For their wide range of potential applications, synthesizing colloidal QDs with high crystal quality is of crucial importance. However, like most common QD systems such as CdSe and PbS, those reported perovskite QDs still suffer from a certain density of trapping defects, giving rise to detrimental nonradiative recombination centers and thus quenching luminescence. In this paper, we show that a high room-temperature photoluminescence quantum yield of up to 100% can be obtained in CsPbI 3 perovskite QDs, signifying the achievement of almost complete elimination of the trapping defects. This is realized with our improved synthetic protocol that involves introducing organolead compound trioctylphosphine-PbI 2 (TOP-PbI 2 ) as the reactive precursor, which also leads to a significantly improved stability for the resulting CsPbI 3 QD solutions. Ultrafast kinetic analysis with time-resolved transient absorption spectroscopy evidence the negligible electron or hole-trapping pathways in our QDs, which explains such a high quantum efficiency. We expect the successful synthesis of the "ideal" perovskite QDs will exert profound influence on their applications to both QD-based light-harvesting and -emitting devices.

  20. Uranyl fluoride luminescence in acidic aqueous solutions

    International Nuclear Information System (INIS)

    Beitz, J.V.; Williams, C.W.

    1996-01-01

    Luminescence emission spectra and decay rates are reported for uranyl species in acidic aqueous solutions containing HF or added NaF. The longest luminescence lifetime, 0.269 ± 0.006 ms, was observed from uranyl in 1 M HF + 1 M HClO 4 at 296 K and decreased with increasing temperature. Based on a luminescence dynamics model that assumes equilibrium among electronically excited uranyl fluoride species and free fluoride ion, this long lived uranyl luminescence in aqueous solution is attributed primarily to UO 2 F 2 . Studies on the effect of added LiNO 3 or Na 2 WO 4 ·2H 2 O showed relatively weak quenching of uranyl fluoride luminescence which suggests that high sensitivity determination of the UF 6 content of WF 6 gas should be feasible via uranyl luminescence analysis of hydrolyzed gas samples of impure WF 6

  1. Preparation of high-purity Pr(3+) doped Ge–Ga–Sb–Se glasses with intensive middle infrared luminescence

    Energy Technology Data Exchange (ETDEWEB)

    Karaksina, E.V.; Shiryaev, V.S., E-mail: shiryaev@ihps.nnov.ru; Kotereva, T.V.; Churbanov, M.F.

    2016-02-15

    Glass materials with high emission characteristics and low content of limiting impurities are required for creation of devices for middle infrared (mid-IR) fiber optics. The paper presents the results of preparation of high-purity Pr{sup 3+}-doped Ga{sub x}Ge{sub y}Sb{sub z}Se{sub 1−(x+y+z)} (x=3÷4, y=20÷26, z=5÷11) glasses. The multi-stage technique for synthesis of these glasses is developed. It is based on chemical distillation purification of glass components and the transport reaction for purification of gallium. Transmitting, as well as thermal and luminescent properties of glasses are investigated. The content of limiting impurities of oxygen, carbon and hydrogen in the glass samples was ≤0.2 ppm wt. The 1300–3000 ppm wt Pr{sup 3+}-doped Ga–Ge–Sb–Se bulk glasses exhibit an intensive photoluminescence in the spectral range of 3.5–5.5 μm.

  2. Utilization of star-shaped polymer architecture in the creation of high-density polymer brush coatings for the prevention of platelet and bacteria adhesion

    Science.gov (United States)

    Totani, Masayasu; Terada, Kayo; Terashima, Takaya; Kim, Ill Yong; Ohtsuki, Chikara; Xi, Chuanwu; Tanihara, Masao

    2014-01-01

    We demonstrate utilization of star-shaped polymers as high-density polymer brush coatings and their effectiveness to inhibit the adhesion of platelets and bacteria. Star polymers consisting of poly(2-hydroxyethyl methacrylate) (PHEMA) and/or poly(methyl methacrylate) (PMMA), were synthesized using living radical polymerization with a ruthenium catalyst. The polymer coatings were prepared by simple drop casting of the polymer solution onto poly(ethylene terephthalate) (PET) surfaces and then dried. Among the star polymers prepared in this study, the PHEMA star polymer (star-PHEMA) and the PHEMA/PMMA (mol. ratio of 71/29) heteroarm star polymer (star-H71M29) coatings showed the highest percentage of inhibition against platelet adhesion (78–88% relative to noncoated PET surface) and Escherichia coli (94–97%). These coatings also showed anti-adhesion activity against platelets after incubation in Dulbecco's phosphate buffered saline or surfactant solution for 7 days. In addition, the PMMA component of the star polymers increased the scratch resistance of the coating. These results indicate that the star-polymer architecture provides high polymer chain density on PET surfaces to prevent adhesion of platelets and bacteria, as well as coating stability and physical durability to prevent exposure of bare PET surfaces. The star polymers provide a simple and effective approach to preparing anti-adhesion polymer coatings on biomedical materials against the adhesion of platelets and bacteria. PMID:25485105

  3. Analyte-triggered luminescence of Eu{sup 3+} ions encapsulated in Nafion membranes -preparation of hybrid materials from in membrane chemical reactions-

    Energy Technology Data Exchange (ETDEWEB)

    Aguilar-Sánchez, Rocío, E-mail: raguilar@ifuap.buap.mx [Depto. Química Analítica, Facultad de Ciencias Químicas, Benemérita Universidad Autónoma de Puebla, Puebla 72570 (Mexico); Zelocualtecatl-Montiel, Iván [Depto. Química Analítica, Facultad de Ciencias Químicas, Benemérita Universidad Autónoma de Puebla, Puebla 72570 (Mexico); Gálvez-Vázquez, María de Jesús [Depto. Química Analítica, Facultad de Ciencias Químicas, Benemérita Universidad Autónoma de Puebla, Puebla 72570 (Mexico); Instituto de Física, Benemérita Universidad Autónoma de Puebla, Apartado postal J-48, Puebla 72570 (Mexico); Silva-González, Rutilo [Instituto de Física, Benemérita Universidad Autónoma de Puebla, Apartado postal J-48, Puebla 72570 (Mexico)

    2017-04-15

    The possibility to perform chemical reactions inside polymer materials opens a unique opportunity to control and prepare materials for diverse solid-state applications. Based on the affinity of Eu{sup 3+} ions for oxygen functionalities, in this work we report the luminescence enhancement of Eu{sup 3+} ions inserted in Nafion membranes (Naf/Eu{sup 3+}) by in-situ complexing to oxalate. The formation of a europium-oxalate type complex enhances Eu{sup 3+} luminescence emission, which could be exploited for the construction of devices for oxalate sensing and the fabrication of highly luminescent materials. Possible analytical applications of Naf/Eu{sup 3+} membranes were evaluated by fluorescence spectroscopy through the linear response with concentration. The complex formation was followed by infrared spectroscopy and SEM-EDS analysis. - Highlights: • Luminescence enhancement by complexation of Eu{sup 3+} ions to oxalate inside Nafion. • Performance of chemical reactions inside Nafion/polymer membranes. • An easy and novel method to prepare luminescent solid devices. • Possibility to develop luminescent sensors by analyte-triggered optical response.

  4. High-energy X-ray detection using organic luminescent materials: a novel application for radiation therapy

    International Nuclear Information System (INIS)

    Schimitberger, Thiago; Ferreira, Giovana Ribeiro; Silva, Mariana de Melo; Saraiva, M.F.; Bianchi, Rodrigo Fernando

    2010-01-01

    In this work, it is presented the characterization and fabrication of a novel ionizing radiation sensor for high energy X-ray (6 MeV). It is used organic luminescent materials usually applied in light-emitting and nanostructure device, but still few explored in radiation dosimetry. Organic solutions of tris(8-hydroxyquinolinato) aluminum - Alq_3 and poly[2-methoxy-5-(2'-ethylhexyloxy)-p-phenylene vinylene] - MEH-PPV were prepared to better study the impact of spectral overlap between the Alq_3 emission and MEH-PPV absorption. It is observed a blue-shift on the photoluminescence of the MEH-PPV/Alq_3 solution system from red-orange (λ_m_a_x = 598 nm) to green (λ_m_a_x = 545 nm) when the radiation dose changes from 0 to 100 Gy. This effect is attributed to the photooxidation process of MEH-PPV and was employed to design dose accumulation sensors in order to represent easily the radiation dose for cancer treatment. (author)

  5. Highly efficient upconversion luminescence in hexagonal NaYF4:Yb3+, Er3+ nanocrystals synthesized by a novel reverse microemulsion method

    Science.gov (United States)

    Gunaseelan, M.; Yamini, S.; Kumar, G. A.; Senthilselvan, J.

    2018-01-01

    A new reverse microemulsion system is proposed for the first time to synthesize NaYF4:Yb,Er nanocrystals, which demonstrated high upconversion emission in 550 and 662 nm at 980 nm diode laser excitation. The reverse microemulsion (μEs) system is comprised of CTAB and oleic acid as surfactant and 1-butanol co-surfactant and isooctane oil phase. The surfactant to water ratio is able to tune the microemulsion droplet size from 14 to 220 nm, which eventually controls the crystallinity and particulate morphology of NaYF4:Yb,Er. Also, the microemulsion precursor and calcination temperature plays certain role in transforming the cubic NaYF4:Yb,Er to highly luminescent hexagonal crystal structured upconversion material. Single phase hexagonal NaYF4:YbEr nanorod prepared by water-in-oil reverse microemulsion (μEs) gives intense red upconversion emission. Both nanosphere and nanorod shaped NaYF4:Yb,Er was obtained, but nanorod morphology resulted an enhanced upconversion luminescence. The structural, morphological, thermal and optical luminescence properties of the NaYF4:Yb,Er nanoparticles are discussed in detail by employing powder X-ray diffraction, dynamic light scattering, high resolution electron microscopy, TGA-DTA, UV-DRS, FTIR and photoluminescence spectroscopy. Intense upconversion emission achieved in the microemulsion synthesized NaYF4:Yb3+,Er3+ nanocrystal can make it as useful optical phosphor for solar cell applications.

  6. Luminescence of highly excited nonpolar a-plane GaN and AlGaN/GaN multiple quantum wells

    International Nuclear Information System (INIS)

    Jursenas, S.; Kuokstis, E.; Miasojedovas, S.; Kurilcik, G.; Zukauskas, A.; Chen, C.Q.; Yang, J.W.; Adivarahan, V.; Asif Khan, M.

    2004-01-01

    Carrier recombination dynamics in polar and nonpolar GaN epilayers and GaN/AlGaN multiple quantum wells grown over sapphire substrates with a various crystallographic orientation were studied under high photoexcitation by 20 ps laser pulses. The transient luminescence featured a significant enhancement on nonradiative recombination of free carriers for nonpolar a-plane GaN epilayers compared to conventional c-plane samples. The epitaxial layer overgrowth technique was demonstrated to significantly improve the quality of nonpolar a-plane films. This was proved by more than 40-fold increase in luminescence decay time (430 ps compared to ≤ 10 ps in the ordinary a-plane epilayer). Under high-excitation regime, a complete screening of built-in electric field by free carriers in multiple quantum wells grown on c-plane and r-plane sapphire substrates was achieved. Under such high excitation, luminescence efficiency and carrier lifetime of multiple quantum wells were shown to be determined by the substrate quality. (author)

  7. High-performance polymer/layered silicate nanocomposites

    Science.gov (United States)

    Heidecker, Matthew J.

    High-performance layered-silicate nanocomposites of Polycarbonate (PC), poly(ethylene terephthalate) (PET), and their blends were produced via conventional melt-blending techniques. The focus of this thesis was on the fundamentals of dispersion, control of thermal stability, maintenance of melt-blending processing conditions, and on optimization of the composites' mechanical properties via the design of controlled and thermodynamically favorable nano-filler dispersions within the polymer matrices. PET and PC require high temperatures for melt-processing, rendering impractical the use of conventional/commercial organically-modified layered-silicates, since the thermal degradation temperatures of their ammonium surfactants lies below the typical processing temperatures. Thus, different surfactant chemistries must be employed in order to develop melt-processable nanocomposites, also accounting for polymer matrix degradation due to water (PET) or amine compounds (PC). Novel high thermal-stability surfactants were developed and employed in montmorillonite nanocomposites of PET, PC, and PC/PET blends, and were compared to the respective nanocomposites based on conventional quaternary-ammonium modified montmorillonites. Favorable dispersion was achieved in all cases, however, the overall material behavior -- i.e., the combination of crystallization, mechanical properties, and thermal degradation -- was better for the nanocomposites based on the thermally-stable surfactant fillers. Studies were also done to trace, and ultimately limit, the matrix degradation of Polycarbonate/montmorillonite nanocomposites, through varying the montmorillonite surfactant chemistry, processing conditions, and processing additives. Molecular weight degradation was, maybe surprisingly, better controlled in the conventional quaternary ammonium based nanocomposites -- even though the thermal stability of the organically modified montmorillonites was in most cases the lowest. Dependence of the

  8. Polymer nanocomposites for high-temperature composite repair

    Energy Technology Data Exchange (ETDEWEB)

    Sheng, Xia [Iowa State Univ., Ames, IA (United States)

    2008-01-01

    A novel repair agent for resin-injection repair of advanced high temperature composites was developed and characterized. The repair agent was based on bisphenol E cyanate ester (BECy) and reinforced with alumina nanoparticles. To ensure good dispersion and compatibility with the BECy matrix in nanocomposites, the alumina nanoparticles were functionalized with silanes. The BECy nanocomposites, containing bare and functionalized alumina nanoparticles, were prepared and evaluated for their thermal, mechanical, rheological, and viscoelastic properties. The monomer of BECy has an extremely low viscosity at ambient temperature, which is good for processability. The cured BECy polymer is a highly cross-linked network with excellent thermal mechanical properties, with a high glass transition temperature (Tg) of 270 C and decomposition temperature above 350 C. The incorporation of alumina nanoparticles enhances the mechanical and rheological properties of the BECy nanocomposites. Additionally, the alumina nanoparticles are shown to catalyze the cure of BECy. Characterization of the nanocomposites included dynamic mechanical analysis, differential scanning calorimetry, thermogravimetric analysis, rheological and rheokinetic evaluation, and transmission electron microscopy. The experimental results show that the BECy nanocomposite is a good candidate as repair agent for resin-injection repair applications.

  9. A series of novel metal–organic coordination polymers constructed from the new 5-(4-imidazol-1-yl-phenyl)-2H-tetrazole spacer and aromatic carboxylates: Synthesis, crystal structures, and luminescence properties

    International Nuclear Information System (INIS)

    Sun, Jiayin; Zhang, Daojun; Wang, Li; Zhang, Renchun; Wang, Junjie; Zeng, Ying; Zhan, Jinling; Xu, Jianing; Fan, Yong

    2013-01-01

    Using bifunctional organic ligand 5-(4-imidazol-1-yl-phenyl)-2H-tetrazole (HL) and different aromatic carboxylates as secondary ligands, four novel metal-organic coordination polymers, [Zn(L)(1,4-bdc) 0.5 ] (1), [Zn 1.5 (L)(2,5-pydc)] (2), [Zn(HL)(1,2,4,5-btec) 0.5 ] (3), and [Cd(HL)(1,2,4,5-btec) 0.5 ] (4) (1,4-bdc, 1,4-benzenedicarboxylate; 2,5-pydc, 2,5-pyridinedicarboxylate; 1,2,4,5-btec, 1,2,4,5-benzenetetracarboxylate) have been successfully synthesized and analyzed. Compound 1 features the 2D [Zn(L)] n layers built by μ 3 -L bridging ligands and Zn(II) ions, which are further linked by pillared 1,4-bdc 2− ligands to form a 2-fold interpenetrating dmc framework. The 3D network of compound 2 can be simplified as a rare 2-nodal (3,6)-connected rtl (rutile) topology. Compound 3 possesses a 2D layer structure which is accomplished by connecting ladder-chains to L ligands. Compound 4 exhibits 2D [Cd(1,2,4,5-btec)] layers with infinite Cd–O–Cd rods and the adjacent 2D networks are further pillared by L with terminal bidentate coordination mode to generate the final 3D structure. The solid-state luminescent studies show that compounds 1–4 display intense fluorescent emissions. - Graphical abstract: Using bifunctional organic ligand 5-(4-imidazol-1-yl-phenyl)-2H-tetrazole (HL) and different aromatic carboxylates as secondary ligands, four novel metal-organic coordination polymers have been obtained. All compounds show good luminescence properties at room temperature. Display Omitted - Highlights: • Four Zn(II)/Cd(II)-MOCPs have been successfully prepared with the rigid bifunctional ligand 5-(4-imidazol -1-yl-phenyl) -2H-tetrazole and different aromatic carboxylates mixed ligands. • Compound 2 is a 2-nodal rtl (rutile) net and compound 4 is a binodal (5, 6)-connected net with yav topology. • Compounds 1-4 display intense fluorescent emissions at room temperature

  10. Development of high-throughput analysis system using highly-functional organic polymer monoliths

    International Nuclear Information System (INIS)

    Umemura, Tomonari; Kojima, Norihisa; Ueki, Yuji

    2008-01-01

    The growing demand for high-throughput analysis in the current competitive life sciences and industries has promoted the development of high-speed HPLC techniques and tools. As one of such tools, monolithic columns have attracted increasing attention and interest in the last decade due to the low flow-resistance and excellent mass transfer, allowing for rapid separations and reactions at high flow rates with minimal loss of column efficiency. Monolithic materials are classified into two main groups: silica- and organic polymer-based monoliths, each with their own advantages and disadvantages. Organic polymer monoliths have several distinct advantages in life-science research, including wide pH stability, less irreversible adsorption, facile preparation and modification. Thus, we have so far tried to develop organic polymer monoliths for various chemical operations, such as separation, extraction, preconcentration, and reaction. In the present paper, recent progress in the development of organic polymer monoliths is discussed. Especially, the procedure for the preparation of methacrylate-based monoliths with various functional groups is described, where the influence of different compositional and processing parameters on the monolithic structure is also addressed. Furthermore, the performance of the produced monoliths is demonstrated through the results for (1) rapid separations of alklybenzenes at high flow rates, (2) flow-through enzymatic digestion of cytochrome c on a trypsin-immobilized monolithic column, and (3) separation of the tryptic digest on a reversed-phase monolithic column. The flexibility and versatility of organic polymer monoliths will be beneficial for further enhancing analytical performance, and will open the way for new applications and opportunities both in scientific and industrial research. (author)

  11. Highly efficient tandem polymer solar cells with a photovoltaic response in the visible light range.

    Science.gov (United States)

    Zheng, Zhong; Zhang, Shaoqing; Zhang, Maojie; Zhao, Kang; Ye, Long; Chen, Yu; Yang, Bei; Hou, Jianhui

    2015-02-18

    Highly efficient polymer solar cells with a tandem structure are fabricated by using two excellent photovoltaic polymers and a highly transparent intermediate recombination layer. Power conversion -efficiencies over 10% can be realized with a photovoltaic response within 800 nm. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Synergistic effect of fluorination on molecular energy level modulation in highly efficient photovoltaic polymers.

    Science.gov (United States)

    Zhang, Maojie; Guo, Xia; Zhang, Shaoqing; Hou, Jianhui

    2014-02-01

    The synergistic effect of fluorination on molecular energy level modulation is realized by introducing fluorine atoms onto both the donor and the acceptor moieties in a D-A polymer, and as a result, the polymer solar cell device based on the trifluorinated polymer, PBT-3F, shows a high efficiency of 8.6%, under illumination of AM 1.5G, 100 mW cm(-) (2) . © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Material Compressing Test of the High Polymer Part Used in Draft Gear of Heavy Load Locomotive

    Directory of Open Access Journals (Sweden)

    Wei Yangang

    2016-01-01

    Full Text Available According to the actual load cases of heavy load locomotive, the material compressing tests of the high polymer parts used in the locomotive are researched. The relationship between stress and strain during the material compressing are acquired by means of comparing the many results of the material compressing tests under different test condition. The relationship between stress and strain during the material compressing is nonlinear in large range of strain, but the relationship is approximately linear in small range of strain. The material of the high polymer made in China and the material of the high polymer imported are compared through the tests. The results show that the compressing property of the material of the high polymer made in China and the material of the high polymer imported are almost same. The research offers the foundation to study the structure elasticity of the draft gear.

  14. High pressure luminescence studies of localized excitations in ZnS doped with Pb2+ and Mn2+

    International Nuclear Information System (INIS)

    House, G.L.; Drickamer, H.G.

    1977-01-01

    High pressure luminescence measurements have been made on ZnS doped with Pb +2 and Mn +2 . The data include changes in peak energy and shape, integrated intensities, and lifetimes. These localized emissions are treated in terms of a single configuration coordinate model. For Pb +2 the emission peak shifted to lower energy by a moderate amount and narrowed. For excitation in the Pb +2 absorption the intensity was independent of pressure, which is consistent with the fact that the energy barrier for radiationless return to the ground state was high at all pressures. For excitation in the ZnS absorption edge the intensity decreased significantly with pressure above about 80 kbar. Data on shifts of the conduction band with pressure would indicate that one is approaching a transition from a direct to indirect transition at high pressure so that decrease in emission intensity may be associated with decreased absorption efficiency. The Mn+ 2 emission peak shifted strongly to lower energy with increasing pressure. The direction and magnitude of the shift were consistent with the predictions of ligand field theory. The intensity doubled in 100 kbar, while the lifetime decreased by roughly a factor of 2. These results could be described in terms of a model for a phonon assisted transition. In addition, peak location, intensity, and lifetime measurements were made on ZnS:Pb:Mn. There is clear evidence of energy transfer by exchange, but in addition there is a nonradiative process in the doubly doped crystal which affects both intensities and lifetimes

  15. High-throughput screening of ionic conductivity in polymer membranes

    International Nuclear Information System (INIS)

    Zapata, Pedro; Basak, Pratyay; Carson Meredith, J.

    2009-01-01

    Combinatorial and high-throughput techniques have been successfully used for efficient and rapid property screening in multiple fields. The use of these techniques can be an advantageous new approach to assay ionic conductivity and accelerate the development of novel materials in research areas such as fuel cells. A high-throughput ionic conductivity (HTC) apparatus is described and applied to screening candidate polymer electrolyte membranes for fuel cell applications. The device uses a miniature four-point probe for rapid, automated point-to-point AC electrochemical impedance measurements in both liquid and humid air environments. The conductivity of Nafion 112 HTC validation standards was within 1.8% of the manufacturer's specification. HTC screening of 40 novel Kynar poly(vinylidene fluoride) (PVDF)/acrylic polyelectrolyte (PE) membranes focused on varying the Kynar type (5x) and PE composition (8x) using reduced sample sizes. Two factors were found to be significant in determining the proton conducting capacity: (1) Kynar PVDF series: membranes containing a particular Kynar PVDF type exhibited statistically identical mean conductivity as other membranes containing different Kynar PVDF types that belong to the same series or family. (2) Maximum effective amount of polyelectrolyte: increments in polyelectrolyte content from 55 wt% to 60 wt% showed no statistically significant effect in increasing conductivity. In fact, some membranes experienced a reduction in conductivity.

  16. High Resolution Shear Profile Measurements in Entangled Polymers

    KAUST Repository

    Hayes, Keesha A.

    2008-11-17

    We use confocal microscopy and particle image velocimetry to visualize motion of 250-300 nm. fluorescent tracer particles in entangled polymers subject to a rectilinear shear flow. Our results show linear velocity profiles in polymer solutions spanning a wide range of molecular weights and number of entanglements (8≤Z≤56), but reveal large differences between the imposed and measured shear rates. These findings disagree with recent reports that shear banding is a characteristic flow response of entangled polymers, and instead point to interfacial slip as an important source of strain loss. © 2008 The American Physical Society.

  17. Fixation of tritium in a highly stable polymer form

    International Nuclear Information System (INIS)

    Steinberg, M.; Colombo, P.; Pruzansky, J.

    1977-01-01

    A method for the fixation of tritium comprises reacting tritiated water with calcium carbide to produce calcium hydroxide and tritiated acetylene, polymerizing the acetylene, and then incorporating the polymer in a solidifying matrix. 2 claims

  18. Dithiopheneindenofluorene (TIF) Semiconducting Polymers with Very High Mobility in Field-Effect Transistors

    KAUST Repository

    Chen, Hu

    2017-07-19

    The charge-carrier mobility of organic semiconducting polymers is known to be enhanced when the energetic disorder of the polymer is minimized. Fused, planar aromatic ring structures contribute to reducing the polymer conformational disorder, as demonstrated by polymers containing the indacenodithiophene (IDT) repeat unit, which have both a low Urbach energy and a high mobility in thin-film-transistor (TFT) devices. Expanding on this design motif, copolymers containing the dithiopheneindenofluorene repeat unit are synthesized, which extends the fused aromatic structure with two additional phenyl rings, further rigidifying the polymer backbone. A range of copolymers are prepared and their electrical properties and thin-film morphology evaluated, with the co-benzothiadiazole polymer having a twofold increase in hole mobility when compared to the IDT analog, reaching values of almost 3 cm2 V−1 s−1 in bottom-gate top-contact organic field-effect transistors.

  19. Toward High Performance Photovoltaic Cells based on Conjugated Polymers

    Science.gov (United States)

    2016-12-26

    polymer are complementary for enhancing the absorption of the solar spectrum while their energy bands are offset structure for facilitating charge ...display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ORGANIZATION. 1. REPORT DATE (DD-MM-YYYY)      28-12-2016 2...the small molecule and the polymer are complementary for enhancing the absorption of the solar spectrum while their energy bands are offset structure

  20. High Charge Carrier Mobility Polymers for Organic Transistors

    OpenAIRE

    Erdmann, Tim

    2017-01-01

    I) Introduction p-Conjugated polymers inherently combine electronic properties of inorganic semiconductor crystals and material characteristics of organic plastics due to their special molecular design. This unique combination has led to developing new unconventional optoelectronic technologies and, further, resulted in the evolution of semiconducting polymers (SCPs) as fundamental components for novel electronic devices, such as organic field-effect transistors (OFETs), organic light-emit...

  1. High effective atomic number polymer scintillators for gamma ray spectroscopy

    Science.gov (United States)

    Cherepy, Nerine Jane; Sanner, Robert Dean; Payne, Stephen Anthony; Rupert, Benjamin Lee; Sturm, Benjamin Walter

    2014-04-15

    A scintillator material according to one embodiment includes a bismuth-loaded aromatic polymer having an energy resolution at 662 keV of less than about 10%. A scintillator material according to another embodiment includes a bismuth-loaded aromatic polymer having a fluor incorporated therewith and an energy resolution at 662 keV of less than about 10%. Additional systems and methods are also presented.

  2. Highly luminescent colloidal Eu(3)+-doped KZnF(3) nanoparticles for the selective and sensitive detection of Cu(II) ions.

    Science.gov (United States)

    Sarkar, Shyam; Chatti, Manjunath; Mahalingam, Venkataramanan

    2014-03-17

    This article describes a green synthetic approach to prepare water dispersible perovskite-type Eu3+-doped KZnF3 nanoparticles, carried out using environmentally friendly microwave irradiation at low temperature (85 8C) with water as a solvent. Incorporation of Eu3+ ions into the KZnF3 matrix is confirmed by strong red emission upon ultraviolet (UV) excitation of the nanoparticles. The nanoparticles are coated with poly(acrylic acid) (PAA), which enhances the dispersibility of the nanoparticles in hydrophilic solvents. The strong red emission from Eu3+ ions is selectively quenched upon addition of CuII ions, thus making the nanoparticles a potential CuII sensing material. This sensing ability is highly reversible by the addition of ethylenediaminetetraacetic acid (EDTA), with recovery of almost 90% of the luminescence. If the nanoparticles are strongly attached to a positively charged surface, dipping the surface in a CuII solution leads to the quenching of Eu3+ luminescence, which can be recovered after dipping in an EDTA solution. This process can be repeated for more than five cycles with only a slight decrease in the sensing ability. In addition to sensing, the strong luminescence from Eu3+-doped KZnF3 nanoparticles could be used as a tool for bioimaging.

  3. Feldspar, Infrared Stimulated Luminescence

    DEFF Research Database (Denmark)

    Jain, Mayank

    2014-01-01

    This entry primarily concerns the characteristics and the origins of infrared-stimulated luminescence in feldspars.......This entry primarily concerns the characteristics and the origins of infrared-stimulated luminescence in feldspars....

  4. Insights into the Mechanism and Kinetics of Thermo-Oxidative Degradation of HFPE High Performance Polymer.

    Science.gov (United States)

    Kunnikuruvan, Sooraj; Parandekar, Priya V; Prakash, Om; Tsotsis, Thomas K; Nair, Nisanth N

    2016-06-02

    The growing requisite for materials having high thermo-oxidative stability makes the design and development of high performance materials an active area of research. Fluorination of the polymer backbone is a widely applied strategy to improve various properties of the polymer, most importantly the thermo-oxidative stability. Many of these fluorinated polymers are known to have thermo-oxidative stability up to 700 K. However, for space and aerospace applications, it is important to improve its thermo-oxidative stability beyond 700 K. Molecular-level details of the thermo-oxidative degradation of such polymers can provide vital information to improve the polymer. In this spirit, we have applied quantum mechanical and microkinetic analysis to scrutinize the mechanism and kinetics of the thermo-oxidative degradation of a fluorinated polymer with phenylethenyl end-cap, HFPE. This study gives an insight into the thermo-oxidative degradation of HFPE and explains most of the experimental observations on the thermo-oxidative degradation of this polymer. Thermolysis of C-CF3 bond in the dianhydride component (6FDA) of HFPE is found to be the rate-determining step of the degradation. Reaction pathways that are responsible for the experimentally observed weight loss of the polymer is also scrutinized. On the basis of these results, we propose a modification of HFPE polymer to improve its thermo-oxidative stability.

  5. CO2-Philic polymer membrane with extremely high separation performance

    KAUST Repository

    Yave, Wilfredo

    2010-01-12

    Polymeric membranes are attractive for CO2 separation and concentration from different gas streams because of their versatility and energy efficiency; they can compete with, and they may even replace, traditional absorption processes. Here we describe a simple and powerful method for developing nanostructured and CO2-philic polymer membranes for CO2 separation. A poly(ethylene oxide)-poly(butylene terephthalate) multiblock copolymer is used as membrane material. Smart additives such as polyethylene glycol dibutyl ether are incorporated as spacers or fillers for producing nanostructured materials. The addition of these specific additives produces CO2-philic membranes and increases the CO2 permeability (750 barrer) up to five-fold without the loss of selectivity. The membranes present outstanding performance for CO2 separation, and the measured CO2 flux is extremely high ( > 2 m3 m -2 h-1 bar-1) with selectivity over H2 and N2 of 10 and 40, respectively, making them attractive for CO 2 capture. © 2009 American Chemical Society.

  6. CO2-Philic polymer membrane with extremely high separation performance

    KAUST Repository

    Yave, Wilfredo; Car, Anja; Funari, S.; Nunes, Suzana Pereira; Peinemann, Klaus-Viktor

    2010-01-01

    Polymeric membranes are attractive for CO2 separation and concentration from different gas streams because of their versatility and energy efficiency; they can compete with, and they may even replace, traditional absorption processes. Here we describe a simple and powerful method for developing nanostructured and CO2-philic polymer membranes for CO2 separation. A poly(ethylene oxide)-poly(butylene terephthalate) multiblock copolymer is used as membrane material. Smart additives such as polyethylene glycol dibutyl ether are incorporated as spacers or fillers for producing nanostructured materials. The addition of these specific additives produces CO2-philic membranes and increases the CO2 permeability (750 barrer) up to five-fold without the loss of selectivity. The membranes present outstanding performance for CO2 separation, and the measured CO2 flux is extremely high ( > 2 m3 m -2 h-1 bar-1) with selectivity over H2 and N2 of 10 and 40, respectively, making them attractive for CO 2 capture. © 2009 American Chemical Society.

  7. Highly Sensitive Luminescence Assessment of Bile Acid Using a Balofloxacin-Europium(III) Probe in Micellar Medium

    International Nuclear Information System (INIS)

    Cai, Huan; Zhao, Fang; Si, Hailin; Zhang, Shuaishuai; Wang, Chunchun; Qi, Peirong

    2012-01-01

    A novel and simple method of luminescence enhancement effect for the determination of trace amounts of bile acid was proposed. The procedure was based on the luminescence intensity of the balofloxacin-europium(III) complex that could be strongly enhanced by bile acid in the presence of sodium dodecyl benzene sulfonate (SDBS). Under the optimum conditions, the enhanced luminescence intensity of the system exhibited a good linear relationship with the bile acid concentration in the range 5.0 Χ 10 -9 - 7.0 Χ 10 -7 mol L -1 with a detection limit of 1.3 Χ 10 -9 mol L.1 (3σ). The relative standard deviation (RSD) was 1.7% (n = 11) for 5.0 Χ 10 -8 mol L -1 bile acid. The applicability of the method to the determination of bile acid was demonstrated by investigating the effect of potential interferences and by analyzing human serum and urine samples. The possible enhancement mechanism of luminescence intensity in balofloxacin-europium(III)-bile acid-SDBS system was also discussed briefly

  8. Electric Field Induced Strain in Electrostrictive Polymers Under High Hydrostatic Pressure - System Development and Material Characterization

    National Research Council Canada - National Science Library

    Zhang, Q

    2000-01-01

    ... of (i) developing a high performance piezo-bimorph based dilatometer which can be used to characterize the electric field induced strain response in polymer films under high hydrostatic pressure, (ii...

  9. Record high hole mobility in polymer semiconductors via side-chain engineering.

    Science.gov (United States)

    Kang, Il; Yun, Hui-Jun; Chung, Dae Sung; Kwon, Soon-Ki; Kim, Yun-Hi

    2013-10-09

    Charge carrier mobility is still the most challenging issue that should be overcome to realize everyday organic electronics in the near future. In this Communication, we show that introducing smart side-chain engineering to polymer semiconductors can facilitate intermolecular electronic communication. Two new polymers, P-29-DPPDBTE and P-29-DPPDTSE, which consist of a highly conductive diketopyrrolopyrrole backbone and an extended branching-position-adjusted side chain, showed unprecedented record high hole mobility of 12 cm(2)/(V·s). From photophysical and structural studies, we found that moving the branching position of the side chain away from the backbone of these polymers resulted in increased intermolecular interactions with extremely short π-π stacking distances, without compromising solubility of the polymers. As a result, high hole mobility could be achieved even in devices fabricated using the polymers at room temperature.

  10. Reversible, high molecular weight palladium and platinum coordination polymers based on phosphorus ligands

    NARCIS (Netherlands)

    Paulusse, J.M.J.; Huijbers, J.P.J.; Sijbesma, R.P.

    2005-01-01

    A general strategy for the preparation and characterization of high molecular weight coordination polymers based on bifunctional phosphorus ligands and palladium or platinum dichloride is described. Metal-to-ligand stoichiometry is of key importance for the formation of linear coordination polymers

  11. Reversible, High Molecular Weight Palladium and Platinum Coordination Polymers Based on Phosphorus Ligands

    NARCIS (Netherlands)

    Paulusse, Jos Marie Johannes; Huijbers, Jeroen P.J.; Sijbesma, Rint P.

    2005-01-01

    A general strategy for the preparation and characterization of high molecular weight coordination polymers based on bifunctional phosphorus ligands and palladium or platinum dichloride is described. Metal-to-ligand stoichiometry is of key importance for the formation of linear coordination polymers

  12. Deformation and degradation of polymers in ultra-high-pressure liquid chromatography

    NARCIS (Netherlands)

    Uliyanchenko, E.; van der Wal, S.; Schoenmakers, P.J.

    2011-01-01

    Ultra-high-pressure liquid chromatography (UHPLC) using columns packed with sub-2 μm particles has great potential for separations of many types of complex samples, including polymers. However, the application of UHPLC for the analysis of polymers meets some fundamental obstacles. Small particles

  13. The Influence of Morphology on High-Performance Polymer Field-Effect Transistors

    DEFF Research Database (Denmark)

    Tsao, Hoi Nok; Cho, Don; Andreasen, Jens Wenzel

    2009-01-01

    The influence of molecular packing on the performance of polymer organic field-effect transistors is illustrated in this work. Both close -stacking distance and long-range order are important for achieving high mobilities. By aligning the polymers from solution, long-range order is induced...

  14. College-Mentored Polymer/Materials Science Modules for Middle and High School Students

    Science.gov (United States)

    Lorenzini, Robert G.; Lewis, Maurica S.; Montclare, Jin Kim

    2011-01-01

    Polymers are materials with vast environmental and economic ramifications, yet are generally not discussed in secondary education science curricula. We describe a program in which college mentors develop and implement hands-on, polymer-related experiments to supplement a standard, state regents-prescribed high school chemistry course, as well as a…

  15. Photophysical studies of highly luminescent europium(III) and terbium(III) complexes functionalized with amino and mercapto groups

    Energy Technology Data Exchange (ETDEWEB)

    Souza, E.R.; Monteiro, J.H.S.K.; Mazali, I.O.; Sigoli, F.A., E-mail: fsigoli@iqm.unicam.br

    2016-02-15

    This work proposes the replacement of coordinated-water molecules from the precursor complexes [Ln(aba){sub 3}(H{sub 2}O)] and [Ln(tta){sub 3}(H{sub 2}O){sub 2}], (Ln=Eu{sup 3+}, Gd{sup 3+} or Tb{sup 3+}, aba{sup −}=aminobenzoate, tta{sup −}=thenoyltrifluoroacetonate) by the ligands mercaptobenzoate (mba{sup −}), mercaptopropionate (mpa{sup −}), phenanthroline (phen), dimethylformamide (dmf) and acetoacetanilide (aaa{sup −}), leading to anionic or neutral amino (–NH{sub 2}) or mercapto (–SH) functionalized-lantanides (III) complexes with reasonable emission quantum yields for potential application on fluorescence microscopy of biological moieties. The complexes photophysical properties were studied using luminescence spectroscopy and theoretical models to determine the transfer and back energy transfer rates and quantum yields, that were compared with experimental ones. The anionic complexes [Eu(tta){sub 3}(L)]{sup −} showed high quantum yield values and their sensitization efficiency are in the range of 39–81%. The overlay of the ground state geometries, obtained from the Sparkle/PM3 model, of the complexes [Eu(tta){sub 3}(aba)]{sup −}, [Eu(tta){sub 3}(mba)]{sup −} and [Eu(tta){sub 3}(mpa)]{sup −}, suggest similar coordination polyhedrons occupied by the europium(III). The highest transfer rates T→{sup 5}D{sub 1,0} were obtained for the anionic complexes [Eu(tta){sub 3}(L)]{sup −} which might be a result of the low triplet level energies and R{sub L} values. - Highlights: • Lanthanides functionalized-complexes. • Free mercapto and amino groups. • Covalence degree of Eu-ligands. • Energy transfer rates. • Intrinsic and absolute quantum yields and sensitization.

  16. Long Range Polymer Chain Dynamics of Highly Flexible Polysiloxane in Solution Probed by Pyrene Excimer Fluorescence

    Directory of Open Access Journals (Sweden)

    Janine L. Thoma

    2018-03-01

    Full Text Available A poly(dimethylsiloxane-co-(3-aminopropylmethylsiloxane polymer (PDMS with 20.3 mol % of (3-aminopropylmethyl siloxane monomer has been labeled randomly with 1-pyreneacetyl groups to generate a series of polysiloxanes (Py-PDMS with pyrenyl contents ranging from 0.7 mol % to 5.2 mol % of the total number of structural units. The remainder of the amino groups were acetylated to avoid intra-chain quenching of the excited singlet states of pyrene via exciplex formation with free amino groups while allowing the formation of excimers to proceed. The fluorescence spectra and temporal decays of the Py-PDMS samples were acquired in tetrahydrofuran (THF, N,N-dimethylformamide (DMF, and dioxane. blob, the average rate constant for intra-chain pyrene excimer formation, was determined from the analysis of the fluorescence decays. blob was found to equal 1.16 (±0.13 × 109, 1.14 (±0.12 × 109, and 0.99 (±0.10 × 109 s−1 in THF, DMF, and dioxane, respectively, at room temperature. They are the largest values found to date for any polymeric backbone in these solvents. The qualitative relationship found here between blob and the chemical structures of the polymers indicates that the luminescence characteristics of randomly labeled polymers is a very useful method to probe the long range dynamics of chains of almost any polymer that is amenable to substitution by a lumophore.

  17. Novel and easy access to highly luminescent Eu and Tb doped ultra-small CaF2, SrF2 and BaF2 nanoparticles - structure and luminescence.

    Science.gov (United States)

    Ritter, Benjamin; Haida, Philipp; Fink, Friedrich; Krahl, Thoralf; Gawlitza, Kornelia; Rurack, Knut; Scholz, Gudrun; Kemnitz, Erhard

    2017-02-28

    A universal fast and easy access at room temperature to transparent sols of nanoscopic Eu 3+ and Tb 3+ doped CaF 2 , SrF 2 and BaF 2 particles via the fluorolytic sol-gel synthesis route is presented. Monodisperse quasi-spherical nanoparticles with sizes of 3-20 nm are obtained with up to 40% rare earth doping showing red or green luminescence. In the beginning luminescence quenching effects are only observed for the highest content, which demonstrates the unique and outstanding properties of these materials. From CaF 2 :Eu10 via SrF 2 :Eu10 to BaF 2 :Eu10 a steady increase of the luminescence intensity and lifetime occurs by a factor of ≈2; the photoluminescence quantum yield increases by 29 to 35% due to the lower phonon energy of the matrix. The fast formation process of the particles within fractions of seconds is clearly visualized by exploiting appropriate luminescence processes during the synthesis. Multiply doped particles are also available by this method. Fine tuning of the luminescence properties is achieved by variation of the Ca-to-Sr ratio. Co-doping with Ce 3+ and Tb 3+ results in a huge increase (>50 times) of the green luminescence intensity due to energy transfer Ce 3+ → Tb 3+ . In this case, the luminescence intensity is higher for CaF 2 than for SrF 2 , due to a lower spatial distance of the rare earth ions.

  18. High Performance All-Polymer Solar Cell via Polymer Side-Chain Engineering

    KAUST Repository

    Zhou, Yan; Kurosawa, Tadanori; Ma, Wei; Guo, Yikun; Fang, Lei; Vandewal, Koen; Diao, Ying; Wang, Chenggong; Yan, Qifan; Reinspach, Julia; Mei, Jianguo; Appleton, Anthony Lucas; Koleilat, Ghada I.; Gao, Yongli; Mannsfeld, Stefan C. B.; Salleo, Alberto; Ade, Harald; Zhao, Dahui; Bao, Zhenan

    2014-01-01

    An average PCE of 4.2% for all-polymer solar cells from 20 devices with an average J SC of 8.8 mA cm-2 are obtained with a donor-acceptor pair despite a low LUMO-LUMO energy offset of less than 0.1 eV. Incorporation of polystyrene side chains into the donor polymer is found to assist in reducing the phase separation domain length scale, and results in more than 20% enhancement of PCE. We observe a direct correlation between the short circuit current (J SC) and the length scale of BHJ phase separation, which is obtained by resonance soft X-ray scattering. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. High Performance All-Polymer Solar Cell via Polymer Side-Chain Engineering

    KAUST Repository

    Zhou, Yan

    2014-03-24

    An average PCE of 4.2% for all-polymer solar cells from 20 devices with an average J SC of 8.8 mA cm-2 are obtained with a donor-acceptor pair despite a low LUMO-LUMO energy offset of less than 0.1 eV. Incorporation of polystyrene side chains into the donor polymer is found to assist in reducing the phase separation domain length scale, and results in more than 20% enhancement of PCE. We observe a direct correlation between the short circuit current (J SC) and the length scale of BHJ phase separation, which is obtained by resonance soft X-ray scattering. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. One-pot synthesis of highly luminescent InP/ZnS nanocrystals without precursor injection.

    Science.gov (United States)

    Li, Liang; Reiss, Peter

    2008-09-03

    InP/ZnS core/shell nanocrystals are prepared using a single-step heating-up method relying on the difference in reactivity of the applied InP and ZnS precursors. The obtained particles exhibit size-dependent emission in the range of 480-590 nm, a fluorescence quantum yield of 50-70%, and high photostability.

  1. The effect of high pressure on the luminescent properties of coumarin 153

    CERN Document Server

    Li Hong; He Li Ming; Wu Shi Kang; Li Yi; Yang Guo Qiang

    2002-01-01

    A dual-fluorescence emitting behaviour of coumarin 153 powder has been detected at high pressure while at ambient pressure the dye exhibits only single-band emission. Because of the strong electron-withdrawal group at site 7, these two fluorescent peaks can be ascribed to local excited state emission and charge transfer state emission, respectively.

  2. Highly luminescent pure-red-emitting fluorinated β-diketonate europium(III) complex for full solution-processed OLEDs

    Energy Technology Data Exchange (ETDEWEB)

    Martins, Joao P. [CEMDRX, Physics Department, Universidade de Coimbra, Rua Larga, Coimbra P-3004-516 (Portugal); Serviço de Medicina Nuclear, SESARAM E.P.E., Avenida Luís de Camões 57, Funchal 9004-514, Madeira (Portugal); Martín-Ramos, Pablo [CEMDRX, Physics Department, Universidade de Coimbra, Rua Larga, Coimbra P-3004-516 (Portugal); Higher Technical School of Telecommunications Engineering, Universidad de Valladolid, Campus Miguel Delibes, Paseo Belén 15, Valladolid 47011 (Spain); Coya, Carmen, E-mail: carmen.coya@urjc.es [Escuela Superior de Ciencias Experimentales y Tecnología (ESCET), Universidad Rey Juan Carlos, Madrid 28933 (Spain); Silva, Manuela Ramos [CEMDRX, Physics Department, Universidade de Coimbra, Rua Larga, Coimbra P-3004-516 (Portugal); Eusebio, M. Ermelinda S. [Chemistry Department, Faculdade de Ciências e Tecnologia, Universidade de Coimbra, Coimbra P-3004-535 (Portugal); Andrés, Alicia de [Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Científicas (CSIC), Cantoblanco, Madrid 28049 (Spain); Álvarez, Ángel L. [Escuela Superior de Ciencias Experimentales y Tecnología (ESCET), Universidad Rey Juan Carlos, Madrid 28933 (Spain); Martín-Gil, Jesús [Advanced Materials Laboratory, ETSIIAA, Universidad de Valladolid, Avenida de Madrid 44, Palencia 34004 (Spain)

    2015-03-15

    Current manufacturing technologies for OLEDs involve the use of expensive high vacuum techniques and call for thermal stability requirements which are not fulfilled by many materials. These problems disappear when the OLED films are deposited directly from solution. In this study, we have designed, synthesized and characterized a novel octacoordinated complex, Tris(1-(4-chlorophenyl)-4,4,4-trifluoro-1, 3-butanedionate)mono(bathophenanthroline) europium(III), to be used as a “complex-only” emissive layer in wet-processed OLEDs. Upon excitation in the UV region, very efficient energy transfer from the ligands to Eu{sup 3+} takes place, giving rise to intense red emission with very high monochromaticity (R=19), both in powder and as a thin film. The decay times of 754 µs (powder) and 620 µs (thin film) are comparable to those of the most efficient Eu{sup 3+} β-diketonate complexes reported to date. The same energy transfer leading to saturated red and narrow emission is also observed in the OLED device (glass/ITO/PEDOT:PSS/[Eu(cbtfa){sub 3}(bath)]/Ca/Al) when biased at >5.2 V. Its high quantum efficiency (∼60%), good thermal stability up to 200 °C and adequate thin film forming properties make this material a promising chromophore for cost-effective OLEDs. - Highlights: • A highly fluorinated europium(III) octacoordinated complex, [Eu(cbtfa)3(bath)], has been synthesized and its structure elucidated by single crystal X-ray diffraction. • The chosen coordination environment is well-suited for sensitizing the luminescence of the Eu{sup 3+} ion, achieving very efficient energy transfer from the organic ligands (excited in the UV region) to the rare earth ion, leading to highly efficient (Q∼60% in crystalline powder and Q∼50% in thin film) and saturated red photoluminescence. • The material has also been integrated into a single active layer, full solution-processed OLED, with ITO/PEDOT:PSS/[Eu(cbtfa)3(bath)]/ Ca/Al structure.

  3. Dosimetry of Al2O3 optically stimulated luminescent dosimeter at high energy photons and electrons

    Science.gov (United States)

    Yusof, M. F. Mohd; Joohari, N. A.; Abdullah, R.; Shukor, N. S. Abd; Kadir, A. B. Abd; Isa, N. Mohd

    2018-01-01

    The linearity of Al2O3 OSL dosimeters (OSLD) were evaluated for dosimetry works in clinical photons and electrons. The measurements were made at a reference depth of Zref according to IAEA TRS 398:2000 codes of practice at 6 and 10 MV photons and 6 and 9 MeV electrons. The measured dose was compared to the thermoluminescence dosimeters (TLD) and ionization chamber commonly used for dosimetry works for higher energy photons and electrons. The results showed that the measured dose in OSL dosimeters were in good agreement with the reported by the ionization chamber in both high energy photons and electrons. A reproducibility test also reported excellent consistency of readings with the OSL at similar energy levels. The overall results confirmed the suitability of OSL dosimeters for dosimetry works involving high energy photons and electrons in radiotherapy.

  4. Polar-solvent-free colloidal synthesis of highly luminescent alkylammonium lead halide perovskite nanocrystals

    Science.gov (United States)

    Vybornyi, Oleh; Yakunin, Sergii; Kovalenko, Maksym V.

    2016-03-01

    A novel synthesis of hybrid organic-inorganic lead halide perovskite nanocrystals (CH3NH3PbX3, X = Br or I) that does not involve the use of dimethylformamide or other polar solvents is presented. The reaction between methylamine and PbX2 salts is conducted in a high-boiling nonpolar solvent (1-octadecene) in the presence of oleylamine and oleic acid as coordinating ligands. The resulting nanocrystals are characterized by high photoluminescence quantum efficiencies of 15-50%, outstanding phase purity and tunable shapes (nanocubes, nanowires, and nanoplatelets). Nanoplatelets spontaneously assemble into micrometer-length wires by face-to-face stacking. In addition, we demonstrate amplified spontaneous emission from thin films of green-emitting CH3NH3PbBr3 nanowires with low pumping thresholds of 3 μJ cm-2.A novel synthesis of hybrid organic-inorganic lead halide perovskite nanocrystals (CH3NH3PbX3, X = Br or I) that does not involve the use of dimethylformamide or other polar solvents is presented. The reaction between methylamine and PbX2 salts is conducted in a high-boiling nonpolar solvent (1-octadecene) in the presence of oleylamine and oleic acid as coordinating ligands. The resulting nanocrystals are characterized by high photoluminescence quantum efficiencies of 15-50%, outstanding phase purity and tunable shapes (nanocubes, nanowires, and nanoplatelets). Nanoplatelets spontaneously assemble into micrometer-length wires by face-to-face stacking. In addition, we demonstrate amplified spontaneous emission from thin films of green-emitting CH3NH3PbBr3 nanowires with low pumping thresholds of 3 μJ cm-2. Electronic supplementary information (ESI) available: Materials and methods, additional figures. See DOI: 10.1039/c5nr06890h

  5. High-pressure cell for luminescence studies of condensed phases at low temperatures

    International Nuclear Information System (INIS)

    Variano, B.F.; Brenner, H.C.; Daniels, W.B.

    1986-01-01

    A clamped optical cell for high-pressure low-temperature fluorescence and phosphorescence studies is described. A particular innovation is the use of a bifurcated fiber-optic lightguide to enable sample illumination and emission collection with a single optical window. This very simple type of cell is adaptable to a variety of optical setups and is easily assembled and disassembled for sample mounting

  6. Luminescence of CsPbBr3 films under high-power excitation

    OpenAIRE

    高橋, 一彰; 斎藤, 忠昭; 近藤, 新一; 浅田, 拡志

    2004-01-01

    Highly excited photoluminescence of CsPbBr3 has been measured for thin films prepared by crystallization from the amorphous phase into microcrystalline/ polycrystalline states. With the increase of excitation intensity, there occurs jumping of the dominant emission band from a free-exciton band to a new band originating from exciton-exciton inelastic collision. Stimulated emission is observed for the new band at very low threshold excitation intensities of the order of 10kW/cm2.

  7. Five new Zn(II) and Cd(II) coordination polymers constructed by 3,5-bis-oxyacetate-benzoic acid: Syntheses, crystal structures, network topologies and luminescent properties

    Energy Technology Data Exchange (ETDEWEB)

    Jiang Xianrong; Yuan Hongyan [Zhejiang Key Laboratory for Reactive Chemistry on Solid Surfaces, Institute of Physical Chemistry, Zhejiang Normal University, Jinhua, Zhejiang 321004 (China); Feng Yunlong, E-mail: sky37@zjnu.edu.cn [Zhejiang Key Laboratory for Reactive Chemistry on Solid Surfaces, Institute of Physical Chemistry, Zhejiang Normal University, Jinhua, Zhejiang 321004 (China)

    2012-07-15

    Five Zn(II) and Cd(II) coordination polymers, [Zn{sub 2}(BOABA)(bpp)(OH)]{center_dot}0.5H{sub 2}O (1), [Cd{sub 3}(BOABA){sub 2}(bpp){sub 2}(H{sub 2}O){sub 6}]{center_dot}2H{sub 2}O (2), [Cd{sub 3}(BOABA){sub 2}(2,2 Prime -bipy){sub 3}(H{sub 2}O){sub 4}]{center_dot}5.5H{sub 2}O (3), [CdNa(BOABA)(H{sub 2}O)]{sub 2}{center_dot}H{sub 2}O (4) and [Cd{sub 2}(BOABA)(bimb)Cl(H{sub 2}O){sub 2}]{center_dot}H{sub 2}O (5) (H{sub 3}BOABA=3,5-bis-oxyacetate-benzoic acid, bpp=1,3-bi(4-pyridyl)propane, 2,2 Prime -bipy=2,2 Prime -bipyridine, bimb=1,4-bis(imidazol-1 Prime -yl)butane), have been solvothermally synthesized and characterized by single-crystal X-ray diffraction, elemental analyses, IR spectra and TG analyses. 1 is an uninodal 4-connected 2D square grid network based on binuclear zinc clusters. 2 is 2D wavelike layer structure and further linked by hydrogen bonds into the final 3D (5,6,6)-connected topology network. 3 is 3-connected 2D topology network and the 2,2 Prime -bipy ligands decorate in two different types. 4 is a (4,8)-connected 2D topology network with heterocaryotic {l_brace}Cd{sub 2}Na{sub 2}{r_brace} clusters and BOABA{sup 3-} ligands. 5 can be rationalized as a (3,10)-connected 3D topology network with tetranuclear {l_brace}Cd{sub 4}Cl{sub 2}{r_brace} clusters and BOABA{sup 3-} ligands. Meanwhile, photoluminescence studies revealed that these five coordination polymers display strong fluorescent emission bands in the solid state at room temperature. - Graphical abstract: Five new d{sup 10} metal(II) coordination polymers based on H{sub 3}BOABA ligand were obtained and characterized. They display different topological structures and luminescent properties. Highlights: Black-Right-Pointing-Pointer Five d{sup 10} metal(II) polymers based on 3,5-bis-oxyacetate-benzoic acid were obtained. Black-Right-Pointing-Pointer The polymers were structurally characterized by single-crystal X-ray diffraction. Black-Right-Pointing-Pointer Polymers 1-5 display different

  8. Molecular design toward highly efficient photovoltaic polymers based on two-dimensional conjugated benzodithiophene.

    Science.gov (United States)

    Ye, Long; Zhang, Shaoqing; Huo, Lijun; Zhang, Maojie; Hou, Jianhui

    2014-05-20

    As researchers continue to develop new organic materials for solar cells, benzo[1,2-b:4,5-b']dithiophene (BDT)-based polymers have come to the fore. To improve the photovoltaic properties of BDT-based polymers, researchers have developed and applied various strategies leading to the successful molecular design of highly efficient photovoltaic polymers. Novel polymer materials composed of two-dimensional conjugated BDT (2D-conjugated BDT) have boosted the power conversion efficiency of polymer solar cells (PSCs) to levels that exceed 9%. In this Account, we summarize recent progress related to the design and synthesis of 2D-conjugated BDT-based polymers and discuss their applications in highly efficient photovoltaic devices. We introduce the basic considerations for the construction of 2D-conjugated BDT-based polymers and systematic molecular design guidelines. For example, simply modifying an alkoxyl-substituted BDT to form an alkylthienyl-substituted BDT can improve the polymer hole mobilities substantially with little effect on their molecular energy level. Secondly, the addition of a variety of chemical moieties to the polymer can produce a 2D-conjugated BDT unit with more functions. For example, the introduction of a conjugated side chain with electron deficient groups (such as para-alkyl-phenyl, meta-alkoxyl-phenyl, and 2-alkyl-3-fluoro-thienyl) allowed us to modulate the molecular energy levels of 2D-conjugated BDT-based polymers. Through the rational design of BDT analogues such as dithienobenzodithiophene (DTBDT) or the insertion of larger π bridges, we can tune the backbone conformations of these polymers and modulate their photovoltaic properties. We also discuss the influence of 2D-conjugated BDT on polymer morphology and the blends of these polymers with phenyl-C61 (or C71)-butyric acid methyl ester (PCBM). Finally, we summarize the various applications of the 2D-conjugated BDT-based polymers in highly efficient PSC devices. Overall, this Account

  9. LUMINESCENCE DETERMINATION OF ETODOLAC

    Directory of Open Access Journals (Sweden)

    A. V. Yegorova

    2015-02-01

    Full Text Available A highly sensitive, simple and rapid method for determination of non-steroidal anti- inflammatory drug – etodolac (Et in washings from surfaces of pharmaceutical equipment have been proposed. The intensity of native luminescence of water-n-propanol solutions of etodolac (λex= 274 nm; λlum= 350 nm was used as the analytical signal. The calibration graph is linear in the concentration range 0.014-2.3 μg/ml, the limit of detection is 0.5 ng/ml.

  10. Vinyl Flanked Difluorobenzothiadiazole-Dithiophene Conjugated Polymer for High Performance Organic Field-Effect Transistors.

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Xianfeng; Sun, Wandong; Chen, Yanlin; Tan, Luxi; Cai, Zheng-Xu; Liu, Zitong; Wang, Lin; Li, Jing; Chen, Wei; Dong, Lichun

    2018-02-21

    Fluorine containing conjugated polymers have been widely applied in high performance organic solar cells, but their use in field-effect transistors is still quite limited. In this work, a conjugated polymer PTFBTV based on difluorobenzothiadiazole (DFBT) and dithiophene was synthesized, utilizing multiple vinylene as linkers. The polymer exhibits a relatively high hole mobility up to 2.0 cm(2) V-1 s(-1) compared with the reported DFBT-oligothiophene based polymers, yet its structural complexity is much simpler. The polymer thin film exhibits a typical 'face on' molecular orientation. A single crystal of its monomer revealed a non-covalent intramolecular contact between fluorine and the neighbouring proton, which strengthens the backbone co-planarity. Meanwhile an intermolecular F...F contact was also observed, which might cause rather scattered lamellar crystallinity for PTFBTV in the solid state.

  11. High performance lignin-acrylonitrile polymer blend materials

    Energy Technology Data Exchange (ETDEWEB)

    Naskar, Amit K.; Tran, Chau D.

    2017-11-14

    A polymer blend material comprising: (i) a lignin component having a weight-average molecular weight of up to 1,000,000 g/mol; and (ii) an acrylonitrile-containing copolymer rubber component comprising acrylonitrile units in combination with diene monomer units, and having an acrylonitrile content of at least 20 mol %; wherein said lignin component is present in an amount of at least 5 wt % and up to about 95 wt % by total weight of components (i) and (ii); and said polymer blend material possesses a tensile yield stress of at least 5 MPa, or a tensile stress of at least 5 MPa at 10% elongation, or a tensile stress of at least 5 MPa at 100% elongation. Methods for producing the polymer blend, molded forms thereof, and articles thereof, are also described.

  12. Observation of the energy transfer sequence in an organic host–guest system of a luminescent polymer and a phosphorescent molecule

    Energy Technology Data Exchange (ETDEWEB)

    Basel, Tek; Sun, Dali; Gautam, Bhoj; Valy Vardeny, Z., E-mail: val@physics.utah.edu

    2014-11-15

    We used steady state optical spectroscopies such as photoluminescence and photoinduced absorption (PA), and magnetic-field PA (MPA) for studying the energy transfer dynamics in films and organic light emitting diodes (OLED) based on host–guest blends with different guest concentrations of the fluorescent polymer poly-[2-methoxy, 5-(2′-ethyl-hexyloxy)phenylene vinylene] (MEHPPV-host), and phosphorescent molecule PtII-tetraphenyltetrabenzoporphyrin [Pt(tpbp); guest]. We show that the energy transfer process between the excited states of the host polymer and guest molecule takes a ‘ping-pong’ type sequence, because the lowest guest triplet exciton energy, E{sub T}(guest), lies higher than that of the host, E{sub T}(host). Upon photon excitation the photogenerated singlet excitons in the host polymer chains first undergo a Förster resonant energy transfer process to the guest singlet manifold, which subsequently reaches E{sub T}(guest) by intersystem crossing. Because E{sub T}(guest)>E{sub T}(host) there is a subsequent Dexter type energy transfer from E{sub T}(guest) to E{sub T}(host). This energy transfer sequence has profound influence on the photoluminescence and electroluminescence emission spectra in both films and OLED devices based on the MEHPPV-Pt(tpbp) system. - Highlights: • We studied electroluminescence of OLEDs based on host–guest blends. • The emission efficiency decreases with the guest concentration. • We found a dominant Dexter energy transfer from the triplet(guest) to triplet(host). • Energy transfer occurs from the host to guest and back to the host again.

  13. Observation of the energy transfer sequence in an organic host–guest system of a luminescent polymer and a phosphorescent molecule

    International Nuclear Information System (INIS)

    Basel, Tek; Sun, Dali; Gautam, Bhoj; Valy Vardeny, Z.

    2014-01-01

    We used steady state optical spectroscopies such as photoluminescence and photoinduced absorption (PA), and magnetic-field PA (MPA) for studying the energy transfer dynamics in films and organic light emitting diodes (OLED) based on host–guest blends with different guest concentrations of the fluorescent polymer poly-[2-methoxy, 5-(2′-ethyl-hexyloxy)phenylene vinylene] (MEHPPV-host), and phosphorescent molecule PtII-tetraphenyltetrabenzoporphyrin [Pt(tpbp); guest]. We show that the energy transfer process between the excited states of the host polymer and guest molecule takes a ‘ping-pong’ type sequence, because the lowest guest triplet exciton energy, E T (guest), lies higher than that of the host, E T (host). Upon photon excitation the photogenerated singlet excitons in the host polymer chains first undergo a Förster resonant energy transfer process to the guest singlet manifold, which subsequently reaches E T (guest) by intersystem crossing. Because E T (guest)>E T (host) there is a subsequent Dexter type energy transfer from E T (guest) to E T (host). This energy transfer sequence has profound influence on the photoluminescence and electroluminescence emission spectra in both films and OLED devices based on the MEHPPV-Pt(tpbp) system. - Highlights: • We studied electroluminescence of OLEDs based on host–guest blends. • The emission efficiency decreases with the guest concentration. • We found a dominant Dexter energy transfer from the triplet(guest) to triplet(host). • Energy transfer occurs from the host to guest and back to the host again

  14. Fabrication of fluorescent composite with ultrafast aqueous synthesized high luminescent CdTe quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Lei, E-mail: mejswu@ust.hk; Chen, Haibin, E-mail: mejswu@ust.hk, E-mail: mejswu@ust.hk; Wu, Jingshen, E-mail: mejswu@ust.hk, E-mail: mejswu@ust.hk [Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Hong Kong and Fok Ying Tung Graduate School, The Hong Kong University of Science and Technology (Hong Kong); Bi, Xianghong, E-mail: takubatch@gmail.com [Fok Ying Tung Graduate School, The Hong Kong University of Science and Technology (Hong Kong)

    2014-05-15

    Without precursor preparation, inert gas protection and enormous amount of additives and reductants, CdTe quantum dots (QDs) can be rapidly synthesized with high quality. A 600 nm photoluminescence peak wavelength could be obtained within 1 hour's refluxing through minimal addition of 1,2-diaminoethane (DAE). The theoretical design for the experiments are illustrated and further proved by the characterization results with different concentrations and reagents. On the other hand, generation of CdTe QDs was found even under room temperature by applying droplet quantity of DAE. This indicates that QDs can be synthesized with simply a bottle and no enormous additives required. The QDs were mixed into the epoxy matrix through solution casting method with cetyltrimethylammonium (CTA) capping for phase transfer. The acquired epoxy based nanocomposite exhibits good transparency, compatibility and fluorescence.

  15. Novel cookie-with-chocolate carbon dots displaying extremely acidophilic high luminescence

    Science.gov (United States)

    Lu, Siyu; Zhao, Xiaohuan; Zhu, Shoujun; Song, Yubin; Yang, Bai

    2014-10-01

    A fluorescent carbon dot with a cookie-with-chocolate film structure (about 5 × 5 μm2) showed a high fluorescence quantum yield (61.12%) at low pH. It was hydrothermally synthesized from l-serine and l-tryptophan. The formation mechanism of the film with carbon dots (CDs) was investigated. The film structure was formed by hydrogen bonding and π-π stacking interactions between aromatic rings. The strong blue fluorescence of the CDs increased under strong acidic conditions owing to the changes in the N-groups. These cookie-like CDs are attractive for their potential use as effective fluorescent probes for the sensitive detection of aqueous H+ and Fe3+.A fluorescent carbon dot with a cookie-with-chocolate film structure (about 5 × 5 μm2) showed a high fluorescence quantum yield (61.12%) at low pH. It was hydrothermally synthesized from l-serine and l-tryptophan. The formation mechanism of the film with carbon dots (CDs) was investigated. The film structure was formed by hydrogen bonding and π-π stacking interactions between aromatic rings. The strong blue fluorescence of the CDs increased under strong acidic conditions owing to the changes in the N-groups. These cookie-like CDs are attractive for their potential use as effective fluorescent probes for the sensitive detection of aqueous H+ and Fe3+. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr03965c

  16. Comparison of Cottonwood Dendrochronology and Optically Stimulated Luminescence Geochronometers Along a High Plains Meandering River, Powder River, Montana, USA

    Science.gov (United States)

    Hasse, T. R.; Schook, D. M.

    2017-12-01

    Geochronometers at centennial scales can aid our understanding of process rates in fluvial geomorphology. Plains cottonwood trees (Populus deltoides ssp. Monilifera) in the high plains of the United States are known to germinate on freshly created deposits such as point bars adjacent to rivers. As the trees mature they may be partially buried (up to a few meters) by additional flood deposits. Cottonwood age gives a minimum age estimate of the stratigraphic surface where the tree germinated and a maximum age estimate for overlying sediments, providing quantitative data on rates of river migration and sediment accumulation. Optically Stimulated Luminescence (OSL) of sand grains can be used to estimate the time since the sand grains were last exposed to sunlight, also giving a minimum age estimate of sediment burial. Both methods have disadvantages: Browsing, partial burial, and other damage to young cottonwoods can increase the time required for the tree to reach a height where it can be sampled with a tree corer, making the germination point a few years to a few decades older than the measured tree age; fluvial OSL samples can have inherited age (when the OSL age is older than the burial age) if the sediment was not completely bleached prior to burial. We collected OSL samples at 8 eroding banks of the Powder River Montana, and tree cores at breast height (±1.2 m) from cottonwood trees growing on the floodplain adjacent to the OSL sample locations. Using the Minimum Age Model (MAM) we found that OSL ages appear to be 500 to 1,000 years older than the adjacent cottonwood trees which range in age (at breast height) from 60 to 185 years. Three explanations for this apparent anomaly in ages are explored. Samples for OSL could be below a stratigraphic unconformity relative to the cottonwood germination elevation. Shallow samples for OSL could be affected by anthropogenic mixing of sediments due to plowing and leveling of hay fields. The OSL samples could have

  17. Highly luminescent N, S- Co-doped carbon dots and their direct use as mercury(II) sensor

    International Nuclear Information System (INIS)

    Wang, Yu; Kim, Sung-Hoon; Feng, Liang

    2015-01-01

    Heteroatom doping has been proven as an efficient way to improve the fluorescent efficiency of carbon dots. Co-doping with heteroatoms may introduce more active sites to carbon dots, which would broaden applications of CDs in sensing. In this work, highly luminescent nitrogen and sulfur co-doped carbon dots (NSCDs) were synthesized through a facile one-step microwave assisted method by using citric acid and rubeanic acid as carbon, nitrogen, and sulfur sources. The well-isolated NSCDs not only exhibit an enhanced fluorescent efficiency with a relatively high quantum yield up to 17.6%, but also show potential use as a multi-sensing platform based on their fluorescence “on-off-on” and color changing behaviors. The NSCDs can be directly used for the selective determination of mercury cations without any functionalization. The detection limit is approximately calculated as 0.18 μM and linear range is 0–20 μM. The sensing mechanism is proposed as coordination reaction induced by oligomers upon the carbon core. Furthermore, in the presence of cyanide anions, the fluorescence shows linear recovery associated with the concentration of cyanide, indicating its potential usage for the detection of cyanide ion. The optimized pH range for such fluorescence “on-off-on” sensing system is investigated as pH 6–8, suggesting potential applications in bio-sensing and imaging area. In addition, by adding hydrosulfide anion to NSCDs@Hg 2+ complex, a notable color change could be clearly observed due to the formation of fuscous HgS. In application, a handy test paper for direct and rapid detection of Hg 2+ is manufactured for the evaluation of usage of NSCDs in the real circumstance. - Highlights: • NSCDs were synthesized by using citric acid and rubeanic acid. • NSCDs exhibited an enhanced fluorescent efficiency with high QY up to 17.6%. • NSCDs presented good sensing performance to mercury ions. • NSCDs showed potential use as a multi-sensing platform

  18. Highly luminescent N, S- Co-doped carbon dots and their direct use as mercury(II) sensor

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yu [Key Lab of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China); Department of Advanced Organic Materials Science and Engineering, Kyungpook National University, Daegu, 702-701 (Korea, Republic of); Kim, Sung-Hoon, E-mail: shokim@knu.ac.kr [Department of Advanced Organic Materials Science and Engineering, Kyungpook National University, Daegu, 702-701 (Korea, Republic of); Feng, Liang, E-mail: fengl@dicp.ac.cn [Key Lab of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China)

    2015-08-26

    Heteroatom doping has been proven as an efficient way to improve the fluorescent efficiency of carbon dots. Co-doping with heteroatoms may introduce more active sites to carbon dots, which would broaden applications of CDs in sensing. In this work, highly luminescent nitrogen and sulfur co-doped carbon dots (NSCDs) were synthesized through a facile one-step microwave assisted method by using citric acid and rubeanic acid as carbon, nitrogen, and sulfur sources. The well-isolated NSCDs not only exhibit an enhanced fluorescent efficiency with a relatively high quantum yield up to 17.6%, but also show potential use as a multi-sensing platform based on their fluorescence “on-off-on” and color changing behaviors. The NSCDs can be directly used for the selective determination of mercury cations without any functionalization. The detection limit is approximately calculated as 0.18 μM and linear range is 0–20 μM. The sensing mechanism is proposed as coordination reaction induced by oligomers upon the carbon core. Furthermore, in the presence of cyanide anions, the fluorescence shows linear recovery associated with the concentration of cyanide, indicating its potential usage for the detection of cyanide ion. The optimized pH range for such fluorescence “on-off-on” sensing system is investigated as pH 6–8, suggesting potential applications in bio-sensing and imaging area. In addition, by adding hydrosulfide anion to NSCDs@Hg{sup 2+} complex, a notable color change could be clearly observed due to the formation of fuscous HgS. In application, a handy test paper for direct and rapid detection of Hg{sup 2+} is manufactured for the evaluation of usage of NSCDs in the real circumstance. - Highlights: • NSCDs were synthesized by using citric acid and rubeanic acid. • NSCDs exhibited an enhanced fluorescent efficiency with high QY up to 17.6%. • NSCDs presented good sensing performance to mercury ions. • NSCDs showed potential use as a multi-sensing platform.

  19. New infrared transmitting material via inverse vulcanization of elemental sulfur to prepare high refractive index polymers.

    Science.gov (United States)

    Griebel, Jared J; Namnabat, Soha; Kim, Eui Tae; Himmelhuber, Roland; Moronta, Dominic H; Chung, Woo Jin; Simmonds, Adam G; Kim, Kyung-Jo; van der Laan, John; Nguyen, Ngoc A; Dereniak, Eustace L; Mackay, Michael E; Char, Kookheon; Glass, Richard S; Norwood, Robert A; Pyun, Jeffrey

    2014-05-21

    Polymers for IR imaging: The preparation of high refractive index polymers (n = 1.75 to 1.86) via the inverse vulcanization of elemental sulfur is reported. High quality imaging in the near (1.5 μm) and mid-IR (3-5 μm) regions using high refractive index polymeric lenses from these sulfur materials was demonstrated. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Luminescent tracks of high-energy photoemitted electrons accelerated by plasmonic fields

    Directory of Open Access Journals (Sweden)

    Di Vece Marcel

    2015-12-01

    Full Text Available The emission of an electron from a metal nanostructure under illumination and its subsequent acceleration in a plasmonic field forms a platform to extend these phenomena to deposited nanoparticles, which can be studied by state-of-the-art confocal microscopy combined with femtosecond optical excitation. The emitted and accelerated electrons leave defect tracks in the immersion oil, which can be revealed by thermoluminescence. These photographic tracks are read out with the confocal microscope and have a maximum length of about 80 μm, which corresponds to a kinetic energy of about 100 keV. This energy is consistent with the energy provided by the intense laser pulse combined with plasmonic local field enhancement. The results are discussed within the context of the rescattering model by which electrons acquire more energy. The visualization of electron tracks originating from plasmonic field enhancement around a gold nanoparticle opens a new way to study with confocal microscopy both the plasmonic properties of metal nano objects as well as high energy electron interaction with matter.

  1. Pure Cs4PbBr6: Highly Luminescent Zero-Dimensional Perovskite Solids

    KAUST Repository

    Saidaminov, Makhsud I.

    2016-09-26

    So-called zero-dimensional perovskites, such as Cs4PbBr6, promise outstanding emissive properties. However, Cs4PbBr6 is mostly prepared by melting of precursors that usually leads to a coformation of undesired phases. Here, we report a simple low-temperature solution-processed synthesis of pure Cs4PbBr6 with remarkable emission properties. We found that pure Cs4PbBr6 in solid form exhibits a 45% photoluminescence quantum yield (PLQY), in contrast to its three-dimensional counterpart, CsPbBr3, which exhibits more than 2 orders of magnitude lower PLQY. Such a PLQY of Cs4PbBr6 is significantly higher than that of other solid forms of lower-dimensional metal halide perovskite derivatives and perovskite nanocrystals. We attribute this dramatic increase in PL to the high exciton binding energy, which we estimate to be ∼353 meV, likely induced by the unique Bergerhoff–Schmitz–Dumont-type crystal structure of Cs4PbBr6, in which metal-halide-comprised octahedra are spatially confined. Our findings bring this class of perovskite derivatives to the forefront of color-converting and light-emitting applications.

  2. High pressure study of viscosity effects on the luminescence of tetracyanobenzene EDA complexes

    Science.gov (United States)

    Thomas, Michele Moisio; Drickamer, H. G.

    1981-03-01

    High pressure fluorescence studies fron 0-10 kbar have been performed on electron donor-acceptor (EDA) complexes of s-tetracyanobenzene (TCNB) with a series of aromatic hydrocarbons. Four solvents were used, 2,2,4,4,6,8,8 heptamethylnonane (HMN), methylcyclohexane (MCH), 2,6,10,14 tetramethylpentadecane (TMPD), and a mixture of MCH and HMN. A viscosity range from 0.006 to 10 000 poise was covered at constant temperature. As pressure (viscosity) increased the fluorescence spectrum shifted from one dominated by emission from the equilibrium (EQ) excited singlet state to one dominated by Franck-Condon (FC) singlet emission. Lifetime measurements for the complexes of o-xylene and p-xylene with TCNB as well as one mesitylene complex yielded the two radiative rates (kEQ and kFC) as well as the rate of internal conversion from FC to the EQ excited state to (kIC). The results are discussed in terms of the rate of relaxation of the solvent compared with the rate kFC. It was found that kIC correlated very well with the solvent viscosity.

  3. Three d10 coordination polymers assembled from 3,5-bis(imidazole-1-yl)pyridine and different polycarboxylates: Syntheses, structures and luminescence properties

    Science.gov (United States)

    Pan, Jie; Zhang, Di; Xue, Zhen-Zhen; Wei, Li; Han, Song-De; Wang, Guo-Ming

    2017-11-01

    Three novel Zn(II)/Cd(II) coordination polymers, [Cd2(bip)2(m-bdc)2(H2O)2·3H2O]n (1), [Zn2(bip)2(p-bdc)2·2.5H2O]n (2) and [Zn(bip) (p-bdc)·3H2O]n (3), where bip = 3,5-bis(imidazole-1-yl)pyridine, m-H2bdc = 1,3-benzenedicarboxylic acid, p-H2bdc = 1,4-benzenedicarboxylic acid, have been successfully synthesized under solvothermal conditions. The linkage of different ligands with Cd(II) ions in compound 1 affords a (3,5)-connected layer. Furthermore, 2D→3D parallel polycatenation occurs wherein the layers are polycatenated with the adjacent two parallel layers to form a 3D framework. In 2 and 3, the polycarboxylates act as pillars to combine the metal-bip chains, yielding the layered structures. These 2D networks are extended to the final 3D supramolecular architectures by π-π stacking interactions. The results show that bip can act as a versatile building block for the construction of various coordination polymers. Moreover, the fluorescent properties of 1-3 in the solid state at room temperature have been investigated.

  4. Mercury coordination polymers with flexible ethane-1,2-diyl-bis-(pyridyl-3-carboxylate): Synthesis, structures, thermal and luminescent properties

    Energy Technology Data Exchange (ETDEWEB)

    Vallejos, Javier [Departamento de Química, Universidad Católica del Norte, Av. Angamos 0610, Antofagasta (Chile); Brito, Iván, E-mail: ivanbritob@yahoo.com [Departamento de Quimica, Universidad de Antofagasta, Av. Angamos 601, Antofagasta (Chile); Cárdenas, Alejandro [Departamento de Física, Universidad de Antofagasta, Av. Angamos 601, Antofagasta (Chile); Llanos, Jaime [Departamento de Química, Universidad Católica del Norte, Av. Angamos 0610, Antofagasta (Chile); Bolte, Michael [Institut für Anorganische Chemie der Goethe—Universität Frankfurt, Max-von-Laue-Strasse 7, D-60438 Frankfurt am Main (Germany); López-Rodríguez, Matías [Instituto de Bio-Orgánica “Antonio González”, Universidad de La Laguna, Astrofísico Francisco Sánchez N° 2, La Laguna, Tenerife (Spain)

    2015-03-15

    The reaction of the flexible ligand, ethane-1,2-diyl-bis-(pyridyl-3-carboxylate), (L) with HgI{sub 2} and HgBr{sub 2} salts under the same experimental conditions leads to the formation of two coordination polymers with different motifs: ([Hg(L)(Br{sub 2})]){sub n}(1) and ([Hg(L)(I{sub 2})]){sub n}(2). In both compounds, the ligand, (L) acts in a μ2-N:N′-bidentate fashion to link HgBr{sub 2} and HgI{sub 2} units to form a linear and helical chain motif, along [1 0 0] for (1) and [0 0 1] for (2). The ethylene moiety of (L) has gauche and trans conformation in compounds (1) and (2), respectively. The flexible conformation of L produces differences in the optical and crystal properties of the two compounds. - Graphical abstract: This work demonstrates how the HgX{sub 2} units are coordinates by bi-dentate ligand forming polymeric coordination complexes by self-assembly of both chemical units.- Highlights: • News 1-D d{sup 10} transition metal coordination polymers. • The photoluminescent properties have been measured. • The thermal properties have been measured.

  5. High-Permeability Magnetic Polymer Additives for Lightweight Electromagnetic Shielding

    Science.gov (United States)

    2015-08-01

    incorporation) or chemical incorporation as part of the polymer chain backbone or linked as pendant groups.13 Many transition-metal organometallic...10.1002/9781119951438. 15. Poli R. Open-shell organometallics as a bridge between Werner-type and low-valent organometallic complexes: the effect

  6. Polymer supported sulphanilic acid: A highly efficient and recyclable ...

    Indian Academy of Sciences (India)

    The resulting chloromethylated styrene- divinylbenzene copolymer beads were designated as. P2 and analysed for chlorine content by Stepnow method.37. 2.3 Procedure for polymer supported sulphanilic acid (P3). P2 (5 gm) were dispersed in methanol (15 ml) and allowed to swell for 2 h. To the swollen bead, aque-.

  7. Electrolyte penetration into high energy ion irradiated polymers

    Czech Academy of Sciences Publication Activity Database

    Fink, D.; Petrov, A.; Müller, M.; Asmus, T.; Hnatowicz, Vladimír; Vacík, Jiří; Červená, Jarmila

    158/159 (2002), s. 228-233 ISSN 0257-8972 R&D Projects: GA AV ČR KSK1010104; GA ČR GA102/01/1324 Keywords : polymers * ion bombardment * defects * diffusion * nanostructrure Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.267, year: 2002

  8. High Thermal Conductivity Polymer Composites for Low Cost Heat Exchangers

    Energy Technology Data Exchange (ETDEWEB)

    None

    2017-08-01

    This factsheet describes a project that identified and evaluated commercially available and state-of-the-art polymer-based material options for manufacturing industrial and commercial non-metallic heat exchangers. A heat exchanger concept was also developed and its performance evaluated with heat transfer modeling tools.

  9. Strategies for dispersing carbon nanotubes in highly viscous polymers

    NARCIS (Netherlands)

    Grossiord, N.; Loos, J.; Koning, C.E.

    2005-01-01

    We describe a new technique based on latex technology, which allows the production of conductive composites with potential applications in electronics. These composites consist of exfoliated single-wall nanotubes in a polymer matrix of choice, with very low percolation threshold.

  10. Strategies, linkers and coordination polymers for high-performance sorbents

    Science.gov (United States)

    Matzger, Adam J.; Wong-Foy, Antek G.; Lebel, Oliver

    2015-09-15

    A linking ligand compound includes three bidentate chemical moieties distributed about a central chemical moiety. Another linking ligand compound includes a bidentate linking ligand and a monodentate chemical moiety. Coordination polymers include a plurality of metal clusters linked together by residues of the linking ligand compounds.

  11. Single photon detection and signal analysis for high sensitivity dosimetry based on optically stimulated luminescence with beryllium oxide

    Science.gov (United States)

    Radtke, J.; Sponner, J.; Jakobi, C.; Schneider, J.; Sommer, M.; Teichmann, T.; Ullrich, W.; Henniger, J.; Kormoll, T.

    2018-01-01

    Single photon detection applied to optically stimulated luminescence (OSL) dosimetry is a promising approach due to the low level of luminescence light and the known statistical behavior of single photon events. Time resolved detection allows to apply a variety of different and independent data analysis methods. Furthermore, using amplitude modulated stimulation impresses time- and frequency information into the OSL light and therefore allows for additional means of analysis. Considering the impressed frequency information, data analysis by using Fourier transform algorithms or other digital filters can be used for separating the OSL signal from unwanted light or events generated by other phenomena. This potentially lowers the detection limits of low dose measurements and might improve the reproducibility and stability of obtained data. In this work, an OSL system based on a single photon detector, a fast and accurate stimulation unit and an FPGA is presented. Different analysis algorithms which are applied to the single photon data are discussed.

  12. Synthesis and thermal properties of a novel high temperature alkyl-center-trisphenolic-based phthalonitrile polymer

    International Nuclear Information System (INIS)

    Sheng, Haitong; Peng, Xuegang; Guo, Hui; Yu, Xiaoyan; Tang, Chengchun; Qu, Xiongwei; Zhang, Qingxin

    2013-01-01

    A novel alkyl-center-trisphenolic-based high-temperature phthalonitrile monomer, namely, 1,1,1-tris-[4-(3,4-dicyanophenoxy)phenyl]ethane (TDPE), was synthesized from 1,1,1-tris-(4-hydroxyphenyl)ethane (THPE) via a facile nucleophilic displacement of a nitro-substituent from 4-nitrophthalonitrile (NPN). The structure of TDPE monomer was characterized by Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance spectroscopy ( 1 H and 13 C NMR), elemental analysis (EA). Curing behaviors of TDPE with 4-(aminophenoxy)phthalonitrile (APPH) were recorded by differential scanning calorimetric (DSC) and it showed a large processing window (122 °C) which is favorable to processing TDPE polymers. The structure of TDPE polymer was discussed and the thermal stabilities of TDPE polymer were evaluated by thermogravimetric analysis (TGA). The TDPE polymer exhibits excellent thermal stability, and mechanism of thermal decompositions was explored. Dynamic mechanical analysis (DMA) revealed that the TDPE polymer has high storage modulus and high glass transition temperature (T g > 380 °C). - Highlights: • A novel high-temperature phthalonitrile polymer was synthesized. • Polymerization mechanism was explored. • The polymer shows excellent thermal stability. • Outstanding mechanical properties was achieved: storage modulus = 3.7 GPa, T g > 380 °C. • Thermal decomposition mechanism was discussed

  13. Novel Stable Gel Polymer Electrolyte: Toward a High Safety and Long Life Li-Air Battery.

    Science.gov (United States)

    Yi, Jin; Liu, Xizheng; Guo, Shaohua; Zhu, Kai; Xue, Hailong; Zhou, Haoshen

    2015-10-28

    Nonaqueous Li-air battery, as a promising electrochemical energy storage device, has attracted substantial interest, while the safety issues derived from the intrinsic instability of organic liquid electrolytes may become a possible bottleneck for the future application of Li-air battery. Herein, through elaborate design, a novel stable composite gel polymer electrolyte is first proposed and explored for Li-air battery. By use of the composite gel polymer electrolyte, the Li-air polymer batteries composed of a lithium foil anode and Super P cathode are assembled and operated in ambient air and their cycling performance is evaluated. The batteries exhibit enhanced cycling stability and safety, where 100 cycles are achieved in ambient air at room temperature. The feasibility study demonstrates that the gel polymer electrolyte-based polymer Li-air battery is highly advantageous and could be used as a useful alternative strategy for the development of Li-air battery upon further application.

  14. Highly ductile UV-shielding polymer composites with boron nitride nanospheres as fillers.

    Science.gov (United States)

    Fu, Yuqiao; Huang, Yan; Meng, Wenjun; Wang, Zifeng; Bando, Yoshio; Golberg, Dmitri; Tang, Chengchun; Zhi, Chunyi

    2015-03-20

    Polymer composites with enhanced mechanical, thermal or optical performance usually suffer from poor ductility induced by confined mobility of polymer chains. Herein, highly ductile UV-shielding polymer composites are successfully fabricated. Boron nitride (BN) materials, with a wide band gap of around ∼6.0 eV, are used as fillers to achieve the remarkably improved UV-shielding performance of a polymer matrix. In addition, it is found that spherical morphology BN as a filler can keep the excellent ductility of the composites. For a comparison, it is demonstrated that traditional fillers, including conventional BN powders can achieve the similar UV-shielding performance but dramatically decrease the composite ductility. The mechanism behind this phenomenon is believed to be lubricant effects of BN nanospheres for sliding of polymer chains, which is in consistent with the thermal analyses. This study provides a new design to fabricate UV-shielding composite films with well-preserved ductility.

  15. Peptides Displayed as High Density Brush Polymers Resist Proteolysis and Retain Bioactivity

    Science.gov (United States)

    2015-01-01

    We describe a strategy for rendering peptides resistant to proteolysis by formulating them as high-density brush polymers. The utility of this approach is demonstrated by polymerizing well-established cell-penetrating peptides (CPPs) and showing that the resulting polymers are not only resistant to proteolysis but also maintain their ability to enter cells. The scope of this design concept is explored by studying the proteolytic resistance of brush polymers composed of peptides that are substrates for either thrombin or a metalloprotease. Finally, we demonstrate that the proteolytic susceptibility of peptide brush polymers can be tuned by adjusting the density of the polymer brush and offer in silico models to rationalize this finding. We contend that this strategy offers a plausible method of preparing peptides for in vivo use, where rapid digestion by proteases has traditionally restricted their utility. PMID:25314576

  16. Investigation into scanning tunnelling luminescence microscopy

    International Nuclear Information System (INIS)

    Manson-Smith, S.K.

    2001-01-01

    This work reports on the development of a scanning tunnelling luminescence (STL) microscope and its application to the study of Ill-nitride semiconductor materials used in the production of light emitting devices. STL microscopy is a technique which uses the high resolution topographic imaging capabilities of the scanning tunnelling microscope (STM) to generate high resolution luminescence images. The STM tunnelling current acts as a highly localised source of electrons (or holes) which generates luminescence in certain materials. Light generated at the STM tunnelling junction is collected concurrently with the height variation of the tunnelling probe as it is scanned across a sample surface, producing simultaneous topographic and luminescence images. Due to the very localised excitation source, high resolution luminescence images can be obtained. Spectroscopic resolution can be obtained by using filters. Additionally, the variation of luminescence intensity with tunnel current and with bias voltage can provide information on recombination processes and material properties. The design and construction of a scanning tunnelling luminescence microscope is described in detail. Operating under ambient conditions, the microscope has several novel features, including a new type of miniature inertial slider-based approach motor, large solid-angle light collection optical arrangement and a tip-height regulation system which requires the minimum of operator input. (author)

  17. Highly sensitive sorption-luminescence determination of trace europium with preconcentration on silica chemically modified with iminodiacetic acid

    International Nuclear Information System (INIS)

    Voronina, R.D.; Zorov, N.B.

    2007-01-01

    Features of a sorption-luminescence method for the determination of trace europium were studied. The method includes the preliminary sorption of europium at pH 7.1 from solutions with silica chemically modified with iminodiacetic acid, the subsequent treatment of the sorbent with 2-thenoyltrifluoroacetone at pH 8.0, and the measurement of the intensity of luminescence of the surface three-component europium complex at 613 nm. The effect of moisture as the quencher of luminescence of the surface europium complex was studied, and techniques for its removal were proposed. Sorption in the static mode provides the detection limit of europium of 7 x 10 -5 g/ml. The calibration plot is linear in the range of two orders of magnitude of europium concentration in solutions. The relative standard deviation in the determination of 1.5 x 10 -2 μg/ml europium is 5%. In the dynamic mode of sorption from 1000 ml of an analyzed solution with the use of sorption-desorption, the detection limit of europium of 8 x 10 -7 μg/ml was attained [ru

  18. Polymorphism of a polymer precursor: metastable glycolide polymorph recovered via large scale high-pressure experiments

    DEFF Research Database (Denmark)

    Hutchison, Ian B.; Delori, Amit; Wang, Xiao

    2015-01-01

    Using a large volume high-pressure press a new polymorph of an important precursor for biomedical polymers was isolated in gram quantities and used to seed crystallisation experiments at ambient pressure....

  19. Azaisoindigo conjugated polymers for high performance n-type and ambipolar thin film transistor applications

    KAUST Repository

    Yue, Wan

    2016-09-28

    Two new alternating copolymers, PAIIDBT and PAIIDSe have been prepared by incorporating a highly electron deficient azaisoindigo core. The molecular structure and packing of the monomer is determined from the single crystal X-ray diffraction. Both polymers exhibit high EAs and highly planar polymer backbones. When polymers are used as the semiconducting channel for solution-processed thin film transistor application, good properties are observed. A–A type PAIIDBT exhibits unipolar electron mobility as high as 1.0 cm2 V−1 s−1, D–A type PAIIDSe exhibits ambipolar charge transport behavior with predominately electron mobility up to 0.5 cm2 V−1 s−1 and hole mobility to 0.2 cm2 V−1 s−1. The robustness of the extracted mobility values are also commented on in detail. Molecular orientation, thin film morphology and energetic disorder of both polymers are systematically investigated.

  20. Highly red-shifted NIR emission from a novel anthracene conjugated polymer backbone containing Pt( ii ) porphyrins

    KAUST Repository

    Freeman, D. M. E.; Minotto, A.; Duffy, Warren; Fallon, K. J.; McCulloch, Iain; Cacialli, F.; Bronstein, H.

    2015-01-01

    -monomer is not limited to exclusively highly solubilising moieties. Interestingly, the polymer shows a red-shifted elecroluminescence maximum (510 nm) when compared to its photoluminescence maximum (450 nm) which we attribute to excimer formation. The novel polymer

  1. A highly selective and non-reaction based chemosensor for the detection of Hg2+ ions using a luminescent iridium(III complex.

    Directory of Open Access Journals (Sweden)

    Daniel Shiu-Hin Chan

    Full Text Available We report herein a novel luminescent iridium(III complex with two hydrophobic carbon chains as a non-reaction based chemosensor for the detection of Hg(2+ ions in aqueous solution (<0.002% of organic solvent attributed to the probe solution. Upon the addition of Hg(2+ ions, the emission intensity of the complex was significantly enhanced and this change could be monitored by the naked eye under UV irradiation. The iridium(III complex shows high specificity for Hg(2+ ions over eighteen other cations. The system is capable of detecting micromolar levels of Hg(2+ ions, which is within the range of many chemical systems.

  2. Polymer electronics

    CERN Document Server

    Hsin-Fei, Meng

    2013-01-01

    Polymer semiconductor is the only semiconductor that can be processed in solution. Electronics made by these flexible materials have many advantages such as large-area solution process, low cost, and high performance. Researchers and companies are increasingly dedicating time and money in polymer electronics. This book focuses on the fundamental materials and device physics of polymer electronics. It describes polymer light-emitting diodes, polymer field-effect transistors, organic vertical transistors, polymer solar cells, and many applications based on polymer electronics. The book also disc

  3. Carbon-13 Labeling Used to Probe Cure and Degradation Reactions of High- Temperature Polymers

    Science.gov (United States)

    Meador, Mary Ann B.; Johnston, J. Christopher

    1998-01-01

    High-temperature, crosslinked polyimides are typically insoluble, intractible materials. Consequently, in these systems it has been difficult to follow high-temperature curing or long-term degradation reactions on a molecular level. Selective labeling of the polymers with carbon-13, coupled with solid nuclear magnetic resonance spectrometry (NMR), enables these reactions to be followed. We successfully employed this technique to provide insight into both curing and degradation reactions of PMR-15, a polymer matrix resin used extensively in aircraft engine applications.

  4. Lignin-based monomers: Utilization in high-performance polymers and the effects of their structures on polymer properties

    Science.gov (United States)

    Stanzione, Joseph F., III

    With the uncertainty of petroleum reserves and future crude oil prices, lignocellulosic biomass is becoming an increasingly valuable resource for the sustainable development of fuels, chemicals, and materials, including vinyl ester resins (VERs). Petroleum-based VERs are used to produce polymer composites for a wide variety of commercial applications. Although possessing relatively high moduli, strengths, and glass transition temperatures, commercial VERs typically contain high concentrations of a reactive diluent, such as styrene. However, these reactive diluents are often considered hazardous air pollutants (HAPs), volatile organic compounds (VOCs), and anticipated carcinogens. Moreover, bisphenol-A, which has gained considerable attention due to potential associated health-related issues, is utilized as a precursor in the synthesis of VERs. A green chemistry and engineering approach in the development of new VERs and renewable reactive diluents that are based on lignin is presented in this dissertation. Lignin, which is currently an abundant, renewable waste product of the paper and pulping industry, is primarily burned as a low value fuel. However, lignin has the potential to be a low cost feedstock in future lignocellulosic biorefineries that could yield highly valuable aromatic chemicals (lignin model compounds, LMCs) when strategically depolymerized. The incorporation of aromaticity in a resin's chemical structure is known to improve overall polymer composite performance and the high aromatic content found in lignin is ideal for novel resin development. Highlighted in this dissertation are three projects: (1) the synthesis and characterization of a lignin-based bio-oil resin/reactive diluent, (2) the use of functionalized LMCs as styrene replacements in VERs, and (3) the synthesis and characterization of a vanillin-based resin. Through the use of traditional and new polymer theory coupled with spectroscopic, thermal, and mechanical techniques, structure

  5. Deformation and degradation of polymers in ultra-high-pressure liquid chromatography.

    Science.gov (United States)

    Uliyanchenko, Elena; van der Wal, Sjoerd; Schoenmakers, Peter J

    2011-09-28

    Ultra-high-pressure liquid chromatography (UHPLC) using columns packed with sub-2 μm particles has great potential for separations of many types of complex samples, including polymers. However, the application of UHPLC for the analysis of polymers meets some fundamental obstacles. Small particles and narrow bore tubing in combination with high pressures generate significant shear and extensional forces in UHPLC systems, which may affect polymer chains. At high stress conditions flexible macromolecules may become extended and eventually the chemical bonds in the molecules can break. Deformation and degradation of macromolecules will affect the peak retention and the peak shape in the chromatogram, which may cause errors in the obtained results (e.g. the calculated molecular-weight distributions). In the present work we explored the limitations of UHPLC for the analysis of polymers. Degradation and deformation of macromolecules were studied by collecting and re-injecting polymer peaks and by off-line two-dimensional liquid chromatography. Polystyrene standards with molecular weight of 4 MDa and larger were found to degrade at UHPLC conditions. However, for most polymers degradation could be avoided by using low linear velocities. No degradation of 3-MDa PS (and smaller) was observed at linear velocities up to 7 mm/s. The column frits were implicated as the main sources of polymer degradation. The extent of degradation was found to depend on the type of the column and on the column history. At high flow rates degradation was observed without a column being installed. We demonstrated that polymer deformation preceded degradation. Stretched polymers eluted from the column in slalom chromatography mode (elution order opposite to that in SEC or HDC). Under certain conditions we observed co-elution of large and small PS molecules though a convolution of slalom chromatography and hydrodynamic chromatography. Copyright © 2011 Elsevier B.V. All rights reserved.

  6. Design and synthesis of polymer, carbon and composite electrodes for high energy and high power supercapacitors

    Science.gov (United States)

    Arcila Velez, Margarita Rosa

    Supercapacitors (SCs) are promising energy storage devices because they deliver energy faster than Li-ion batteries and store larger amounts of charge compared to dielectric capacitors. SCs are classified in electrical double layer capacitors (EDLCs) and pseudocapacitors, based on their charge storage mechanism. EDLCs store charge electrostatically, i.e. by physical charge separation. This mechanism limits the storable amount of energy to the available surface area of the electrode, typically made of carbon materials, but grants good cycling stability of the SC device. Pseudocapacitor electrodes, commonly made of conducting polymers or metal oxides, store charge faradaically, i.e. through redox reactions throughout the bulk material, which allows them to store significantly larger amounts of energy than EDLCs, but their stability is compromised due to the partial irreversibility of the faradaic processes. To accomplish the commercialization of SCs, devices must show a combination of high charge storage capacities and long-term stability, besides being cost-effective. To tackle the current issues of SCs, this field of study has taken mainly two directions: 1) the development of new architectures and nanostructures of the active materials, which has shown to increase the surface area, enhance stability, and facilitate ion diffusion; and 2) fabrication of composites between non-faradaic (carbon), faradaic materials, and/or redox-active components to achieve a balance between the amount of energy stored and the stability. Following the first approach, a continuous process to grow vertically aligned carbon nanotubes (VACNTs) on cost-effective aluminum foil was developed. The resulting electrodes were analyzed as SC electrodes and in symmetric cells, and the influence of the arrangement of the nanotubes and the synthesis conditions was studied. The performance of the VACNTs produced continuously showed similar performance to the VACNTs produced stationarily and the

  7. Luminescence and energy transfer

    Energy Technology Data Exchange (ETDEWEB)

    Blasse, G; Bleijenberg, K C; Powell, R C

    1980-01-01

    This paper deals with the luminescence of uranate centres in solids. The luminescence properties are influenced by the coordination number of the hexavalent uranium ion and by the crystallographic surroundings of the uranate centre. Transitions playing a role in the luminescence processes within the octahedral UO/sub 6//sup 6 -/ group are discussed using the results from both theoretical and experimental studies on another octahedral uranium complex: UF/sub 6/. The luminescence of the octahedral uranate group in oxidic compounds is discussed. Attention is paid to the vibrational structure, which is observed in the luminescence spectra at low temperatures and to the temperature quenching of the luminescence. The temperature quenching of the uranate luminescence in uranium-doped tungstates with ordered perovskite structure can be described in terms of a three state single configurational coordinate diagram. The complicated luminescence spectra of uranium-activated sodium fluoride (NaF-U) crystals have been unraveled using chemical variation of the crystal compositions and using site selective laser excitation techniques. Four different luminescent uranate centres have been observed in NaF-U. A model for the configurations of the luminescent centres has been deduced using the results from ionic conductivity experiments.

  8. Highly sensitive urea sensing with ion-irradiated polymer foils

    International Nuclear Information System (INIS)

    Fink, Dietmar; Muñoz Hernandez, Gerardo; Alfonta, Lital

    2012-01-01

    Recently we prepared urea-sensors by attaching urease to the inner walls of etched ion tracks within thin polymer foil. Here, alternative track-based sensor configurations are examined where the enzyme remained in solution. The conductivities of systems consisting of two parallel irradiated polymer foils and confining different urea/urease mixtures in between were examined. The correlations between conductivity and urea concentration differed strongly for foils with unetched and etched tracks, which points at different sensing mechanisms – tentatively attributed to the adsorption of enzymatic reaction products on the latent track entrances and to the enhanced conductivity of reaction product-filled etched tracks, respectively. All examined systems enable in principle, urea sensing. They point at the possibility of sensor cascade construction for more sensitive or selective sensor systems.

  9. High efficiency polymer solar cells with vertically modulated nanoscale morphology

    International Nuclear Information System (INIS)

    Kumar, Ankit; Hong Ziruo; Yang Yang; Li Gang

    2009-01-01

    Nanoscale morphology has been shown to be a critical parameter governing charge transport properties of polymer bulk heterojunction (BHJ) solar cells. Recent results on vertical phase separation have intensified the research on 3D morphology control. In this paper, we intend to modify the distribution of donors and acceptors in a classical BHJ polymer solar cell by making the active layer richer in donors and acceptors near the anode and cathode respectively. Here, we chose [6,6]-phenyl- C 61 -butyric acid methyl ester (PCBM) to be the acceptor material to be thermally deposited on top of [poly(3-hexylthiophene)] P3HT: the PCBM active layer to achieve a vertical composition gradient in the BHJ structure. Here we report on a solar cell with enhanced power conversion efficiency of 4.5% which can be directly correlated with the decrease in series resistance of the device.

  10. High elastic modulus polymer electrolytes suitable for preventing thermal runaway in lithium batteries

    Science.gov (United States)

    Mullin, Scott; Panday, Ashoutosh; Balsara, Nitash Pervez; Singh, Mohit; Eitouni, Hany Basam; Gomez, Enrique Daniel

    2014-04-22

    A polymer that combines high ionic conductivity with the structural properties required for Li electrode stability is useful as a solid phase electrolyte for high energy density, high cycle life batteries that do not suffer from failures due to side reactions and dendrite growth on the Li electrodes, and other potential applications. The polymer electrolyte includes a linear block copolymer having a conductive linear polymer block with a molecular weight of at least 5000 Daltons, a structural linear polymer block with an elastic modulus in excess of 1.times.10.sup.7 Pa and an ionic conductivity of at least 1.times.10.sup.-5 Scm.sup.-1. The electrolyte is made under dry conditions to achieve the noted characteristics. In another aspect, the electrolyte exhibits a conductivity drop when the temperature of electrolyte increases over a threshold temperature, thereby providing a shutoff mechanism for preventing thermal runaway in lithium battery cells.

  11. Integrated Modeling of Polymer Composites Under High Energy Laser Irradiation

    Science.gov (United States)

    2015-10-30

    Toyota , K.; Fukuda, R.; Hasegawa, J.; Ishida, M.; Nakajima, T.; Honda, Y.; Kitao, O.; Nakai, H.; Vreven, T.; Montgomery, J. A., Jr.; Peralta, J. E...Resolution Mapping of Thermal History in Polymer Nanocomposites: Gold Nanorods as Microscale Temperature Sensors W. Joshua Kennedy,†,‡ Keith A. Slinker...of the AuNRs will not be strongly dependent on temperature history . Thus, the final aspect ratio of the AuNRs after heating in a given environment is

  12. Anthracene-containing wide-band-gap conjugated polymers for high-open-circuit-voltage polymer solar cells.

    Science.gov (United States)

    Gong, Xue; Li, Cuihong; Lu, Zhen; Li, Guangwu; Mei, Qiang; Fang, Tao; Bo, Zhishan

    2013-07-25

    The synthesis, characterization, and photophysical and photovoltaic properties of two anthracene-containing wide-band-gap donor and acceptor (D-A) alternating conjugated polymers (P1 and P2) are described. These two polymers absorb in the range of 300-600 nm with a band gap of about 2.12 eV. Polymer solar cells with P1:PC71 BM as the active layer demonstrate a power conversion efficiency (PCE) of 2.23% with a high Voc of 0.96 V, a Jsc of 4.4 mA cm(-2) , and a comparable fill factor (FF) of 0.53 under simulated solar illumination of AM 1.5 G (100 mW cm(-2) ). In addition, P2:PC71 BM blend-based solar cells exhibit a PCE of 1.42% with a comparable Voc of 0.89 V, a Jsc of 3.0 mA cm(-2) , and an FF of 0.53. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Novel polybenzimidazole derivatives for high temperature polymer electrolyte membrane fuel cell applications

    Science.gov (United States)

    Xiao, Lixiang

    Recent advances have made polymer electrolyte membrane fuel cells (PEMFCs) a leading alternative to internal combustion engines for both stationary and transportation applications. In particular, high temperature polymer electrolyte membranes operational above 120°C without humidification offer many advantages including fast electrode kinetics, high tolerance to fuel impurities and simple thermal and water management systems. A series of polybenzimidazole (PBI) derivatives including pyridine-based PBI (PPBI) and sulfonated PBI (SPBI) homopolymers and copolymers have been synthesized using polyphosphoric acid (PPA) as both solvent and polycondensation agent. High molecular weight PBI derivative polymers were obtained with well controlled backbone structures in terms of pyridine ring content, polymer backbone rigidity and degree of sulfonation. A novel process, termed the PPA process, has been developed to prepare phosphoric acid (PA) doped PBI membranes by direct-casting of the PPA polymerization solution without isolation or re-dissolution of the polymers. The subsequent hydrolysis of PPA to PA by moisture absorbed from the atmosphere usually induced a transition from the solution-like state to a gel-like state and produced PA doped PBI membranes with a desirable suite of physiochemical properties characterized by the PA doping levels, mechanical properties and proton conductivities. The effects of the polymer backbone structure on the polymer characteristics and membrane properties, i.e., the structure-property relationships of the PBI derivative polymers have been studied. The incorporation of additional basic nitrogen containing pyridine rings and sulfonic acid groups enhanced the polymer solubility in acid and dipolar solvents while retaining the inherently high thermal stability of the PBI heteroaromatic backbone. In particular, the degradation of the SPBI polymers with reasonable high molecular weights commenced above 450°C, notably higher than other

  14. Towards understanding hydrophobic recovery of plasma treated polymers: Storing in high polarity liquids suppresses hydrophobic recovery

    International Nuclear Information System (INIS)

    Bormashenko, Edward; Chaniel, Gilad; Grynyov, Roman

    2013-01-01

    The phenomenon of hydrophobic recovery was studied for cold air plasma treated polyethylene films. Plasma-treated polymer films were immersed into liquids with very different polarities such as ethanol, acetone, carbon tetrachloride, benzene and carbon disulphide. Hydrophobic recovery was studied by measurement of contact angles. Immersion into high polarity liquids slows markedly the hydrophobic recovery. We relate this slowing to dipole–dipole interaction of polar groups of the polymer with those of the liquids. This kind of interaction becomes decisive when polar groups of polymer chains are at least partially spatially fixed.

  15. Defining Allowable Physical Property Variations for High Accurate Measurements on Polymer Parts

    DEFF Research Database (Denmark)

    Mohammadi, Ali; Sonne, Mads Rostgaard; Madruga, Daniel González

    2015-01-01

    Measurement conditions and material properties have a significant impact on the dimensions of a part, especially for polymers parts. Temperature variation causes part deformations that increase the uncertainty of the measurement process. Current industrial tolerances of a few micrometres demand...... high accurate measurements in non-controlled ambient. Most of polymer parts are manufactured by injection moulding and their inspection is carried out after stabilization, around 200 hours. The overall goal of this work is to reach ±5μm in uncertainty measurements a polymer products which...

  16. High performance all polymer solar cells fabricated via non-halogenated solvents (Presentation Recording)

    Science.gov (United States)

    Zhou, Yan; Bao, Zhenan

    2015-10-01

    The performance of organic solar cells consisting of a donor/acceptor bulk heterojunction (BHJ) has rapidly improved over the past few years.1. Major efforts have been focused on developing a variety of donor materials to gain access to different regions of the solar spectrum as well as to improve carrier transport properties.2 On the other hand, the most utilized acceptors are still restricted to the fullerene family, which includes PC61BM, PC71BM and ICBA.2b, 3 All-polymer solar cells, consisting of polymers for both the donor and acceptor, gained significantly increased interests recently, because of their ease of solution processing, potentially low cost, versatility in molecular design, and their potential for good chemical and morphological stability due to entanglement of polymers. Unlike small molecular fullerene acceptors, polymer acceptors can benefit from the high mobility of intra-chain charge transport and exciton generation by both donor and acceptor. Despite extensive efforts on all-polymer solar cells in the past decade, the fundamental understanding of all-polymer solar cells is still in its inceptive stage regarding both the materials chemistry and structure physics.4 Thus, rational design rules must be utilized to enable fundamental materials understanding of the all polymer solar cells. We report high performance all-polymer solar cells employing polymeric donors based on isoindigo and acceptor based on perylenedicarboximide. The phase separation domain length scale correlates well with the JSC and is found to be highly sensitive to the aromatic co-monomer structures used in the crystalline donor polymers. With the PS polymer side chain engineering, the phase separation domain length scale decreased by more than 45%. The PCE and JSC of the devices increased accordingly by more than 20%. A JSC as high as 10.0 mA cm-2 is obtained with the donor-acceptor pair despite of a low LUMO-LUMO energy offset of less than 0.1 eV. All the factors such as

  17. Three coordination polymers based on a star-like geometry 4, 4', 4'' -nitrilotribenzoic acid ligand and their framework dependent luminescent properties

    Science.gov (United States)

    Hu, Zhiyong; Zhao, Meng; Su, Jian; Xu, Shasha; Hu, Lei; Liu, Hui; Zhang, Qiong; Zhang, Jun; Wu, Jieying; Tian, Yupeng

    2018-02-01

    Three novel coordination polymers, [Zn(μ2-HTCA)(Phen)]n (1), {[Cd(μ3-HTCA)(Phen)]·2H2O}n (2), [Mn(μ2-HTCA)(Phen)(H2O)]n (3) were prepared by hydrothermal synthesis from the 4, 4', 4''-nitrilotribenzoicacid (H3TCA) and 1, 10-phenanthroline monohydrate (Phen) with different transition metal salts, which were characterized by elemental analysis, IR spectra, powder and single-crystal X-ray diffraction and thermogravimetric analysis. The photophysical properties of the complexes were investigated by solid-state diffuse reflectance spectra, photoluminescent properties, lifetime and quantum yield. For these complexes, it was found that the band gaps follow the order: 3 < 2 < 1 < 2.80 eV, fluorescence intensity order: 1 > H3TCA > 2 > 3; quantum yield order: H3TCA > 1 > 2 > 3; while the lifetime order: 1 > 2 > H3TCA > 3.

  18. Theoretical and Experimental Studies of New Polymer-Metal High-Dielectric Constant Nanocomposites

    Science.gov (United States)

    Ginzburg, Valeriy; Elwell, Michael; Myers, Kyle; Cieslinski, Robert; Malowinski, Sarah; Bernius, Mark

    2006-03-01

    High-dielectric-constant (high-K) gate materials are important for the needs of electronics industry. Most polymers have dielectric constant in the range 2 materials with K > 10 it is necessary to combine polymers with ceramic or metal nanoparticles. Several formulations based on functionalized Au-nanoparticles (R ˜ 5 -— 10 nm) and PMMA matrix polymer are prepared. Nanocomposite films are subsequently cast from solution. We study the morphology of those nanocomposites using theoretical (Self-Consistent Mean-Field Theory [SCMFT]) and experimental (Transmission Electron Microscopy [TEM]) techniques. Good qualitative agreement between theory and experiment is found. The study validates the utility of SCMFT as screening tool for the preparation of stable (or at least metastable) polymer/nanoparticle mixtures.

  19. Bipolar and Unipolar Silylene-Diphenylene σ-π Conjugated Polymer Route for Highly Efficient Electrophosphorescence

    Science.gov (United States)

    Chang, Yao-Tang; Sharma, Sunil; Hung, Miao-Ken; Lee, Yu-Hsuan; Chen, Show-An

    2016-12-01

    σ-π conjugated polymer strategy is proposed for designing electroluminescent host polymers with silylene-diphenylene as the backbone repeat unit giving a high triplet energy (ET = 2.67 eV). By incorporation of high ET (3.0 eV) electron (oxadiazole, OXD) and hole (triphenyl amine, TPA) transport moieties, or TPA alone (in this case, the main chain acts as electron transport channel) as side arms on the silylene, the high ET bipolar and unipolar polymers are formed, allowing a use of iridium green phosphor (Ir(ppy)2(acac), Ir-G) (ET = 2.40 eV) as the dopant. The matching of energy levels of the dopant with the hosts, leading to charge trapping into it; and singlets and triplets of the exciplex and excimer can be harvested via energy transfer to the dopant. Using these host-guest systems as the emitting layer, chlorinated indium-tin-oxide (Cl-ITO) as the anode, and benzimidazole derivative (TPBI) as the electron transport layer, this two-layer device gives the high luminance efficiency 80.1 cd/A and external quantum efficiency 21.2%, which is the best among the report values for polymer light emitting diode (PLED) in the literatures. This example manifests that σ-π conjugated polymer strategy is a promising route for designing polymer host for efficient electrophosphorescence.

  20. LUMINESCENCE DIAGNOSTICS OF TUMORS WITH UPCONVERSION NANOPARTICLES

    Directory of Open Access Journals (Sweden)

    V. V. Rocheva

    2016-01-01

    Full Text Available Background: To improve quality of surgery in oncology, it is necessary to completely remove the tumor, including its metastases, to minimize injury to normal tissues and to reduce duration of an intervention. Modern methods of detection based on radiological computerized tomography and magnetic resonance imaging can identify a tumor after its volume has become big enough, i.e. it contains more than 10 billion cells. Therefore, an improvement of sensitivity and resolution ability of diagnostic tools to identify early stages of malignant neoplasms seems of utmost importance. Aim: To demonstrate the potential of a new class of anti-Stokes luminescence nanoparticles for deep optical imaging with high contrast of malignant tumors. Materials and methods: Upconversion nanoparticles with narrow dispersion and a  size of 70 to 80  nm, with a  core/shell structure of NaYF4:Yb3+:Tm3+/NaYF4 were used in the study. The nanoparticles have an intensive band of anti-Stokes photoluminescence at a wavelength of 800  nm under irradiation with a  wavelength of 975  nm (both wavelengths are within the transparency window for biological tissues. The conversion coefficient of the excitation radiation into the anti-Stokes luminescence was 9%. To increase the time during which nanoparticles can circulate in blood flow of small animals, the nanoparticles were covered by a  biocompatible amphiphilic polymer shell. As a  tumor model we used Lewis epidermoid carcinoma transfected to mice. Results: We were able to obtain stable water colloids of nanoparticles covered with amphiphilic polymer that could preserve their initial size at least for one month. The use of upconversion nanoparticles with a  hydrophilic shell made of intermittent maleic anhydride and octadecene co-polymer with subsequent coating with diglycidyl polyethylene glycol ether allowed for reduction of non-specific reaction of nanoparticles with plasma proteins. In its turn, it resulted in an

  1. High-resolution stratigraphy and multiple luminescence dating techniques to reveal the paleoseismic history of the central Dead Sea fault (Yammouneh fault, Lebanon)

    Science.gov (United States)

    Le Béon, Maryline; Tseng, Ya-Chu; Klinger, Yann; Elias, Ata; Kunz, Alexander; Sursock, Alexandre; Daëron, Mathieu; Tapponnier, Paul; Jomaa, Rachid

    2018-07-01

    Continuous sedimentation and detailed stratigraphy are key parameters for a complete paleo-earthquake record. Here, we present a new paleoseismological study across the main strike-slip fault branch of the Dead Sea fault in Lebanon. We aim to expand the current knowledge on local paleoseismicity and seismic behavior of strike-slip plate boundary faults and to explore the limitations of paleoseismology and dating methods. The trench, dug in the Jbab el-Homr basin, reveals a succession of remarkable, very thin (0.1 to 5 cm) palustrine and lacustrine layers, ruptured by at least 17 earthquakes. Absolute ages of 4 samples are obtained from three luminescence-dating techniques targeting fine-grain minerals. Blue-green stimulated luminescence (BGSL) on quartz and post-infrared infrared-stimulated luminescence at 225 °C on polymineral aliquots led to consistent ages, while ages from infrared-stimulated luminescence at 50 °C on polymineral aliquots appeared underestimated. The quartz BGSL ages are 26.9 ± 2.3 ka at 0.50 m depth and 30.8 ± 2.9 ka at 3.65 m depth. During this time period of 3.9 ka ([0; 9.1 ka]), 14 surface-rupturing events occurred with a mean return time of 280 years ([0; 650 years]) and probable clustering. This return time is much shorter than the 1127 ± 135 years return time previously determined at the Yammouneh site, located 30 km south. Although fault segmentation and temporal variations in the earthquake cycle remain possible causes for such different records, we argue that the high-resolution stratigraphy in Jbab is the main factor, enabling us to record small deformations related to smaller-magnitude events that may have been missed in the rougher strata of Yammouneh. Indeed, focusing only on larger events of Jbab, we obtain a mean return time of 720 years ([0; 1670 years]) that is compatible with the Yammouneh record.

  2. Highly Luminescent 2D-Type Slab Crystals Based on a Molecular Charge-Transfer Complex as Promising Organic Light-Emitting Transistor Materials.

    Science.gov (United States)

    Park, Sang Kyu; Kim, Jin Hong; Ohto, Tatsuhiko; Yamada, Ryo; Jones, Andrew O F; Whang, Dong Ryeol; Cho, Illhun; Oh, Sangyoon; Hong, Seung Hwa; Kwon, Ji Eon; Kim, Jong H; Olivier, Yoann; Fischer, Roland; Resel, Roland; Gierschner, Johannes; Tada, Hirokazu; Park, Soo Young

    2017-09-01

    A new 2:1 donor (D):acceptor (A) mixed-stacked charge-transfer (CT) cocrystal comprising isometrically structured dicyanodistyrylbenzene-based D and A molecules is designed and synthesized. Uniform 2D-type morphology is manifested by the exquisite interplay of intermolecular interactions. In addition to its appealing structural features, unique optoelectronic properties are unveiled. Exceptionally high photoluminescence quantum yield (Φ F ≈ 60%) is realized by non-negligible oscillator strength of the S 1 transition, and rigidified 2D-type structure. Moreover, this luminescent 2D-type CT crystal exhibits balanced ambipolar transport (µ h and µ e of ≈10 -4 cm 2 V -1 s -1 ). As a consequence of such unique optoelectronic characteristics, the first CT electroluminescence is demonstrated in a single active-layered organic light-emitting transistor (OLET) device. The external quantum efficiency of this OLET is as high as 1.5% to suggest a promising potential of luminescent mixed-stacked CT cocrystals in OLET applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Highly sensitive and selective cartap nanosensor based on luminescence resonance energy transfer between NaYF4:Yb,Ho nanocrystals and gold nanoparticles.

    Science.gov (United States)

    Wang, Zhijiang; Wu, Lina; Shen, Baozhong; Jiang, Zhaohua

    2013-09-30

    Fluorescent detection is an attractive method for the detection of toxic chemicals. However, most chemosensors that are currently utilized in fluorescent detection are based on organic dyes or quantum dots, which suffer from instability, high background noise and interference from organic impurities in solution, which can also be excited by UV radiation. In the present research, we developed a novel NaYF4:Yb,Ho/Au nanocomposite-based chemosensor with high sensitivity (10 ppb) and selectivity over competing analytes for the detection of the insecticide cartap. This nanosensor is excited with a 970-nm laser instead of UV radiation to give an emission peak at 541 nm. In the presence of cartap, the nanocomposites aggregate, resulting in enhanced luminescence resonance energy transfer between the NaYF4:Yb,Ho nanocrystals and the gold nanoparticles, which decreases the emission intensity at 541 nm. The relative luminescence intensity at 541 nm has a linear relationship with the concentration of cartap in the solution. Based on this behavior, the developed nanosensor successfully detected cartap in farm produce and water samples with satisfactory results. Copyright © 2013 Elsevier B.V. All rights reserved.

  4. The local free volume and its correlation with the structural, chemical and dynamic properties of branched polymers, polymer electrolytes, highly oriented polyethylene fibres and other polymers

    International Nuclear Information System (INIS)

    Bamford, David

    2002-01-01

    frequently observed levelling off of the expansion of the hole volume at high temperatures is proposed in terms of increased thermal motions of the polymer chain segments on a time scale comparable to the o-Ps lifetime. The ionic conductivity of all the samples was found to follow both the Cohen-Turnbull and Vogel Tamman Fulcher theories over changes in the conductivity of several orders of magnitude demonstrating a direct link between the average free volume hole size and the ionic conductivity. Surprisingly, no clear differences were observed between the single ion and mixed ion conductors, showing the conduction mechanism to be independent of the specific interactions between the ions and the polymer chains. At temperatures near or below the glass transition, a change in the ion transport mechanism from a random redistribution of free volume in the rubbery phase to a thermally activated hopping in the glassy phase is observed. The anisotropic 'free volume hole' shape in highly oriented polyethylene fibres is studied using 2-Dimensional Angular Correlation of Annihilation Radiation spectroscopy and a new method of analysing the data is proposed. The average shape of these holes is determined and bears a remarkable similarity to the expected shape of chain fold defects in the crystalline phase. Finally, the potential use of Doppler Broadening of Annihilation Radiation DBAR spectroscopy as a probe of the chemical surroundings of free volume holes in polymers is assessed. Several series of fluorinated polymers are studied using PALS and DBAR spectroscopy and a linear decrease in the S-parameter of the annihilation peak is observed with increasing fluorine content. Using a new coincidence DBAR spectrometer it was found that the presence of oxygen, fluorine or chlorine in polymers could be identified from subtle but characteristic changes in the shape of the annihilation peak. (author)

  5. Broadband luminescence in liquid-solid transition

    CERN Document Server

    Achilov, M F; Trunilina, O V

    2002-01-01

    Broadband luminescence (BBL) intensity behavior in liquid-solid transition in polyethyleneglycol-600 has been established. Oscillation of BBL intensity observed in liquid-polycrystal transition are not found to observed in liquid-amorphous solid transition. It is shown that application of the theory of electron state tails to interpretation of BBL spectral properties in liquids demands restriction. BBL spectroscopy may be applied for optimization of preparation of polymers with determined properties. (author)

  6. Metal-Organic Framework Nanosheets for Fast-Response and Highly Sensitive Luminescent Sensing of Fe3+

    DEFF Research Database (Denmark)

    Xu, Hui; Iversen, Bo Brummerstedt

    of graphene, Since the discovery of graphene, series of two-dimensional (2-D) nanosheets materials such as metal oxides, metal hydroxides, transition metal chalcogenides (TMDs), boron nitride (BN) and black phosphorus have been of great interests, and have been extensively investigated for applications...... in electronics, lithium-ion batteries, catalysis and mechanical properties, etc. 2-D MOF nanosheets materials, as a new member of the 2-D nanomaterials family, are still at the very early stage. However, to the best of our knowledge, the 2-D MOF nanosheets materials for luminescent sensing have been rarely...

  7. Luminescent beam stop

    Energy Technology Data Exchange (ETDEWEB)

    Bryant, Diane; Morton, Simon A.

    2017-10-25

    This disclosure provides systems, methods, and apparatus related to beam stops. In one aspect, a device comprises a luminescent material, a beam stop plate, and an optical fiber. The luminescent material is a parallelepiped having a first side and a second side that are squares and having a third side that is a rectangle or a square. The first side and the second side are perpendicular to the third side. The beam stop plate is attached to the first side of the luminescent material. The optical fiber has a first end and a second end, with the first end of the optical fiber attached to the third side of the luminescent material.

  8. Luminescence detection of shellfish

    International Nuclear Information System (INIS)

    Sanderson, D.C.W.; Carmichael, L.A.; Spencer, J.Q.; Naylor, J.D.

    1996-01-01

    The Scottish Universities Research and Reactor Centre (SURRC) has been active in the development and application of luminescence techniques in the detection of irradiated foods, in support of UK legislation. Thermoluminescence (TL), photostimulated luminescence (PSL) and photo-transfer luminescence (PTTL) are radiation-specific phenomena which arise due to energy stored by trapped charge carriers following irradiation. The energy released following stimulation is accompanied by detectable luminescence. The TL method involves preparation of pure silicate extracts from the sample and subsequent TL analysis, whereas PSL uses stimulation by electromagnetic radiation (visible, or near visible wavelengths) thus avoiding heating the sample. (author)

  9. Recent developments in luminescent solar concentrators

    Science.gov (United States)

    van Sark, W. G. J. H. M.

    2014-10-01

    High efficiency photovoltaic devices combine full solar spectrum absorption and effective generation and collection of charge carriers, while commercial success depends on cost effectiveness in manufacturing. Spectrum modification using down shifting has been demonstrated in luminescent solar concentrators (LSCs) since the 1970s, as a cheap alternative for standard c-Si technology. LSCs consist of a highly transparent plastic plate, in which luminescent species are dispersed, which absorb incident light and emit light at a red-shifted wavelength, with high quantum efficiency. Material issues have hampered efficiency improvements, in particular re-absorption of light emitted by luminescent species and stability of these species. In this contribution, approaches are reviewed on minimizing re-absorption, which should allow surpassing the 10% luminescent solar concentrator efficiency barrier.

  10. Ultra-high polarity ceramics induced extrinsic high permittivity of polymers contributing to high permittivity of 2-2 series composites

    Science.gov (United States)

    Feng, Yefeng; Zhang, Jianxiong; Hu, Jianbing; Peng, Cheng; He, Renqi

    2018-01-01

    Induced polarization at interface has been confirmed to have significant impact on the dielectric properties of 2-2 series composites bearing Si-based semi-conductor sheet and polymer layer. By compositing, the significantly elevated high permittivity in Si-based semi-conductor sheet should be responsible for the obtained high permittivity in composites. In that case, interface interaction could include two aspects namely a strong electrostatic force from high polarity polymeric layer and a newborn high polarity induced in Si-based ceramic sheet. In this work, this class of interface induced polarization was successfully extended into another 2-2 series composite system made up of ultra-high polarity ceramic sheet and high polarity polymer layer. By compositing, the greatly improved high permittivity in high polarity polymer layer was confirmed to strongly contribute to the high permittivity achieved in composites. In this case, interface interaction should consist of a rather large electrostatic force from ultra-high polarity ceramic sheet with ionic crystal structure and an enhanced high polarity induced in polymer layer based on a large polarizability of high polarity covalent dipoles in polymer. The dielectric and conductive properties of four designed 2-2 series composites and their components have been detailedly investigated. Increasing of polymer inborn polarity would lead to a significant elevating of polymer overall polarity in composite. Decline of inherent polarities in two components would result in a mild improving of polymer total polarity in composite. Introducing of non-polarity polymeric layer would give rise to a hardly unaltered polymer overall polarity in composite. The best 2-2 composite could possess a permittivity of ˜463 at 100 Hz 25.7 times of the original permittivity of polymer in it. This work might offer a facile route for achieving the promising composite dielectrics by constructing the 2-2 series samples from two high polarity

  11. High Efficiency Polymer Solar Cells with Long Operating Lifetimes

    KAUST Repository

    Peters, Craig H.; Sachs-Quintana, I. T.; Kastrop, John P.; Beaupré , Serge; Leclerc, Mario; McGehee, Michael D.

    2011-01-01

    Organic bulk-heterojunction solar cells comprising poly[N-9'-hepta-decanyl- 2,7-carbazole-alt-5,5-(4',7'-di-2-thienyl-2', 1',3'-benzothiadiazole) (PCDTBT) are systematically aged and demonstrate lifetimes approaching seven years, which is the longest reported lifetime for polymer solar cells. An experimental set-up is described that is capable of testing large numbers of solar cells, holding each device at its maximum power point while controlling and monitoring the temperature and light intensity. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. High Efficiency Polymer Solar Cells with Long Operating Lifetimes

    KAUST Repository

    Peters, Craig H.

    2011-04-20

    Organic bulk-heterojunction solar cells comprising poly[N-9\\'-hepta-decanyl- 2,7-carbazole-alt-5,5-(4\\',7\\'-di-2-thienyl-2\\', 1\\',3\\'-benzothiadiazole) (PCDTBT) are systematically aged and demonstrate lifetimes approaching seven years, which is the longest reported lifetime for polymer solar cells. An experimental set-up is described that is capable of testing large numbers of solar cells, holding each device at its maximum power point while controlling and monitoring the temperature and light intensity. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Recyclable Cu(II)-Coordination Crosslinked Poly(benzimidazolyl pyridine)s as High-Performance Polymers.

    Science.gov (United States)

    Wang, Cheng; Yang, Li; Chang, Guanjun

    2018-03-01

    Crosslinked high-performance polymers have many industrial applications, but are difficult to recycle or rework. A novel class of recyclable crosslinking Cu(II)-metallo-supramolecular coordination polymers are successfully prepared, which possess outstanding thermal stability and mechanical property. More importantly, the Cu 2+ coordination interactions can be further removed via external pyrophosphate to recover the linear polymers, which endow the crosslinking polymers with recyclability. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Precisely Controlled Ultrathin Conjugated Polymer Films for Large Area Transparent Transistors and Highly Sensitive Chemical Sensors.

    Science.gov (United States)

    Khim, Dongyoon; Ryu, Gi-Seong; Park, Won-Tae; Kim, Hyunchul; Lee, Myungwon; Noh, Yong-Young

    2016-04-13

    A uniform ultrathin polymer film is deposited over a large area with molecularlevel precision by the simple wire-wound bar-coating method. The bar-coated ultrathin films not only exhibit high transparency of up to 90% in the visible wavelength range but also high charge carrier mobility with a high degree of percolation through the uniformly covered polymer nanofibrils. They are capable of realizing highly sensitive multigas sensors and represent the first successful report of ethylene detection using a sensor based on organic field-effect transistors. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Prediction and correlation of high-pressure gas solubility in polymers with simplified PC-SAFT

    DEFF Research Database (Denmark)

    von Solms, Nicolas; Michelsen, Michael Locht; Kontogeorgis, Georgios

    2005-01-01

    Using simplified PC-SAFT we have modeled gas solubilities at high temperatures and pressures for the gases methane and carbon dioxide in each of the three polymers high-density polyethylene (HDPE), nylon polyamide-11 (PA-11), and poly(vinylidene fluoride) (PVDF). In general the results are satisf......Using simplified PC-SAFT we have modeled gas solubilities at high temperatures and pressures for the gases methane and carbon dioxide in each of the three polymers high-density polyethylene (HDPE), nylon polyamide-11 (PA-11), and poly(vinylidene fluoride) (PVDF). In general the results...

  16. Doped polymer electrodes for high performance ferroelectric capacitors on plastic substrates

    KAUST Repository

    Khan, M. A.

    2012-10-03

    Flexible ferroelectric capacitors with doped polymer electrodes have been fabricated on plastic substrates with performance as good as metal electrodes. The effect of doping on the morphology of polymer electrodes and its impact on device performance have been studied. Improved fatigue characteristics using doped and undoped poly (3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) electrodes versus metal electrodes are observed. It is shown that the polymer electrodes follow classical ferroelectric and dielectric responses, including series resistance effects. The improved device characteristics obtained using highly conducting doped PEDOT:PSS suggest that it may be used both as an electrode and as global interconnect for all-polymer transparent circuits on flexible substrates.

  17. Photo-degradation of high efficiency fullerene-free polymer solar cells.

    Science.gov (United States)

    Upama, Mushfika Baishakhi; Wright, Matthew; Mahmud, Md Arafat; Elumalai, Naveen Kumar; Mahboubi Soufiani, Arman; Wang, Dian; Xu, Cheng; Uddin, Ashraf

    2017-12-07

    Polymer solar cells are a promising technology for the commercialization of low cost, large scale organic solar cells. With the evolution of high efficiency (>13%) non-fullerene polymer solar cells, the stability of the cells has become a crucial parameter to be considered. Among the several degradation mechanisms of polymer solar cells, burn-in photo-degradation is relatively less studied. Herein, we present the first systematic study of photo-degradation of novel PBDB-T:ITIC fullerene-free polymer solar cells. The thermally treated and as-prepared PBDB-T:ITIC solar cells were exposed to continuous 1 sun illumination for 5 hours. The aged devices exhibited rapid losses in the short-circuit current density and fill factor. The severe short-circuit current and fill factor burn in losses were attributed to trap mediated charge recombination, as evidenced by an increase in Urbach energy for aged devices.

  18. Controlled fabrication of luminescent and magnetic nanocomposites

    Science.gov (United States)

    Ma, Yingxin; Zhong, Yucheng; Fan, Jing; Huang, Weiren

    2018-03-01

    Luminescent and magnetic multifunctional nanocomposite is in high demand and widely used in many scales, such as drug delivery, bioseparation, chemical/biosensors, and so on. Although lots of strategies have been successfully developed for the demand of multifunctional nanocomposites, it is not easy to prepare multifunctional nanocomposites by using a simple method, and satisfy all kinds of demands simultaneously. In this work, via a facile and versatile method, luminescent nanocrystals and magnetic nanoparticles were successfully synthesized through self-assembly under vigorous stirring and ultrasonic treatment. These multifunctional nanocomposites are not only water stable but also find wide application such as magnetic separation and concentration with a series of moderate speed, multicolor fluorescence at different emission wavelength, high efficiency of the excitation and emission, and so on. By changing different kinds of luminescent nanocrystals and controlling the amount of luminescent and magnetic nanoparticles, a train of multifunctional nanocomposites was successfully fabricated via a versatile and robust method.

  19. Catalytic phosphonation of high performance polymers and POSS. Novel components for polymer blend and nanocomposite fuel cell membranes

    Energy Technology Data Exchange (ETDEWEB)

    Bock, T.R.

    2006-10-15

    Aim of this thesis was the preparation and evaluation of phosphonated high performance (HP) polyelectrolytes and polyhedral oligomeric silsesquioxanes (POSS) for polyelectrolyte membrane fuel cell (PEMFC) application. Brominated derivatives of the commercial high performance (HP) polymers poly(ethersulfone) (PES), poly(etheretherketone) (PEEK), poly(phenylsulfone) (PPSu), poly(sulfone) (PSU) and of octaphenyl-POSS of own production were phosphonated by Ni-catalysed Arbuzov reaction. Phosphonated PSU was cast into pure and blend films with sulfonated PEEK (s-PEEK) to investigate H+-conductivity, water uptake and film morphology. Blend films' properties were referenced to films containing unmodified blend partners. Solution-compounding of phosphonated octaphenyl-POSS and s-PEEK was used to produce novel nanocomposite films. An in-situ zirconisation method was assessed as convenient strategy for novel ionically crosslinked membranes of enhanced swelling resistance. Dibromo isocyanuric acid (DBI) and N-bromo succinimide (NBS) as brominating agents allowed polymer analogous preparation of the novel brominated PES and PEEK with precise reaction control. A random distribution of functional groups, i.e. polyelectrolytes' microstructural homogeneity was revealed as decisive factor concerning solubility of phosphonated PSU. Brominated phT8 was prepared with Br2 by a high temperature approach in tetrachloroethane (TCE). Brominated polymers were phosphonated by Ni-catalysis in non-coordinating high temperature solvents, such as diphenylether, benzophenone and diphenylsulfone without notable solvent influence. The lack of solvent - catalyst complexes and high reaction temperatures of 180-200 C led to halogen-free phosphonates with unprecedented high functionalities. Polymer analogous application of P(OSiMe3)3 offered a novel direct access to easily cleavable disilyl ester derivatives. These were obtained from PEEK and PSU in near quantitative yields at NiCl2-loads as

  20. Analytical Modeling of the High Strain Rate Deformation of Polymer Matrix Composites

    Science.gov (United States)

    Goldberg, Robert K.; Roberts, Gary D.; Gilat, Amos

    2003-01-01

    The results presented here are part of an ongoing research program to develop strain rate dependent deformation and failure models for the analysis of polymer matrix composites subject to high strain rate impact loads. State variable constitutive equations originally developed for metals have been modified in order to model the nonlinear, strain rate dependent deformation of polymeric matrix materials. To account for the effects of hydrostatic stresses, which are significant in polymers, the classical 5 plasticity theory definitions of effective stress and effective plastic strain are modified by applying variations of the Drucker-Prager yield criterion. To verify the revised formulation, the shear and tensile deformation of a representative toughened epoxy is analyzed across a wide range of strain rates (from quasi-static to high strain rates) and the results are compared to experimentally obtained values. For the analyzed polymers, both the tensile and shear stress-strain curves computed using the analytical model correlate well with values obtained through experimental tests. The polymer constitutive equations are implemented within a strength of materials based micromechanics method to predict the nonlinear, strain rate dependent deformation of polymer matrix composites. In the micromechanics, the unit cell is divided up into a number of independently analyzed slices, and laminate theory is then applied to obtain the effective deformation of the unit cell. The composite mechanics are verified by analyzing the deformation of a representative polymer matrix composite (composed using the representative polymer analyzed for the correlation of the polymer constitutive equations) for several fiber orientation angles across a variety of strain rates. The computed values compare favorably to experimentally obtained results.

  1. High-performance polymer waveguide devices via low-cost direct photolithography process

    Science.gov (United States)

    Wang, Jianguo; Shustack, Paul J.; Garner, Sean M.

    2002-09-01

    All-optical networks provide unique opportunities for polymer waveguide devices because of their excellent mechanical, thermo-optic, and electro-optic properties. Polymer materials and components have been viewed as a viable solution for metropolitan and local area networks where high volume and low cost components are needed. In this paper, we present our recent progress on the design and development of photoresist-like highly fluorinated maleimide copolymers including waveguide fabrication and optical testing. We have developed and synthesized a series of thermally stable, (Tg>150 oC, Td>300 oC) highly fluorinated (>50%) maleimide copolymers by radical co-polymerization of halogenated maleimides with various halogenated co-monomers. A theoretical correlation between optical loss and different co-polymer structures has been quantitatively established from C-H overtone analysis. We studied this correlation through design and manipulation of the copolymer structure by changing the primary properties such as molecular weight, copolymer composition, copolymer sequence distribution, and variations of the side chain including photochemically functional side units. Detailed analysis has been obtained using various characterization methods such as (H, C13, F19) NMR, UV-NIR, FTIR, GPC and so forth. The co-polymers exhibit excellent solubility in ketone solvents and high quality thin films can be prepared by spin coating. The polymer films were found to have a refractive index range of 1.42-1.67 and optical loss in the range of 0.2 to 0.4 dB/cm at 1550nm depending on the composition as extrapolated from UV-NIR spectra. When glycidyl methacrylate is incorporated into the polymer backbone, the material behaves like a negative photoresist with the addition of cationic photoinitiator. The final crosslinked waveguides show excellent optical and thermal properties. The photolithographic processing of the highly fluorinated copolymer material was examined in detail using in

  2. Design, fabrication and characterization of an arrayable all-polymer microfluidic valve employing highly magnetic rare-earth composite polymer

    International Nuclear Information System (INIS)

    Rahbar, Mona; Gray, Bonnie L; Shannon, Lesley

    2016-01-01

    We present a new magnetically actuated microfluidic valve that employs a highly magnetic composite polymer (M-CP) containing rare-earth hard-magnetic powder for its actuating element and for its valve seat. The M-CP offers much higher magnetization compared to the soft-magnetic, ferrite-based composite polymers typically used in microfluidic applications. Each valve consists of a permanently magnetized M-CP flap and valve seat mounted on a microfluidic channel system fabricated in poly(dimethylsiloxane) (PDMS). Each valve is actuated under a relatively small external magnetic field of 80 mT provided by a small permanent magnet mounted on a miniature linear actuator. The performance of the valve with different flap thicknesses is characterized. In addition, the effect of the magnetic valve seat on the valve’s performance is also characterized. It is experimentally shown that a valve with a 2.3 mm flap thickness, actuated under an 80 mT magnetic field, is capable of completely blocking liquid flow at a flow rate of 1 ml min −1 for pressures up to 9.65 kPa in microfluidic channels 200 μ m wide and 200 μ m deep. The valve can also be fabricated into an array for flow switching between multiple microfluidic channels under continuous flow conditions. The performance of arrays of valves for flow routing is demonstrated for flow rates up to 5 ml min −1 with larger microfluidic channels of up to 1 mm wide and 500 μ m deep. The design of the valves is compatible with other commonly used polymeric microfluidic components, as well as other components that use the same novel permanently magnetic composite polymer, such as our previously reported cilia-based mixing devices. (paper)

  3. Europium enabled luminescent nanoparticles for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Syamchand, S.S., E-mail: syamchand.ss@gmail.com; Sony, G., E-mail: emailtosony@gmail.com

    2015-09-15

    Lanthanide based nanoparticles are receiving great attention ought to their excellent luminescent and magnetic properties and find challenging biomedical applications. Among the luminescent lanthanide NPs, europium based NPs (Eu-NPs) are better candidates for immunoassay and imaging applications. The Eu-NPs have an edge over quantum dots (QDs) by means of their stable luminescence, long fluorescence lifetime, sharp emission peaks with narrow band width, lack of blinking and biocompatibility. This review surveys the synthesis and properties of a variety of Eu-NPs consolidated from different research articles, for their applications in medicine and biology. The exquisite luminescent properties of Eu-NPs are explored for developing biomedical applications such as immunoassay and bioimaging including multimodal imaging. The biomedical applications of Eu-NPs are mostly diagnostic in nature and mainly focus on various key analytes present in biological systems. The luminescent properties of europium enabled NPs are influenced by a number of factors such as the site symmetry, the metal nanoparticles, metal ions, quantum dots, surfactants, morphology of Eu-NPs, crystal defect, phenomena like antenna effect and physical parameters like temperature. Through this review we explore and assimilate all the factors which affect the luminescence in Eu-NPs and coil a new thread of parameters that control the luminescence in Eu-NPs, which would provide further insight in developing Eu-based nanoprobes for future biomedical prospects. - Highlights: • The review describes 14 major factors that influence the luminescence properties of europium enabled luminescent nanoparticles (Eu-NPs). • Surveys different types of europium containing nanoparticles that have been reported for their biomedical applications. • Eu-NPs are conveniently divided into four different categories, based on the type of the substrates involved. The four categories are (1) virgin Eu-substrate based NPs; (2

  4. Europium enabled luminescent nanoparticles for biomedical applications

    International Nuclear Information System (INIS)

    Syamchand, S.S.; Sony, G.

    2015-01-01

    Lanthanide based nanoparticles are receiving great attention ought to their excellent luminescent and magnetic properties and find challenging biomedical applications. Among the luminescent lanthanide NPs, europium based NPs (Eu-NPs) are better candidates for immunoassay and imaging applications. The Eu-NPs have an edge over quantum dots (QDs) by means of their stable luminescence, long fluorescence lifetime, sharp emission peaks with narrow band width, lack of blinking and biocompatibility. This review surveys the synthesis and properties of a variety of Eu-NPs consolidated from different research articles, for their applications in medicine and biology. The exquisite luminescent properties of Eu-NPs are explored for developing biomedical applications such as immunoassay and bioimaging including multimodal imaging. The biomedical applications of Eu-NPs are mostly diagnostic in nature and mainly focus on various key analytes present in biological systems. The luminescent properties of europium enabled NPs are influenced by a number of factors such as the site symmetry, the metal nanoparticles, metal ions, quantum dots, surfactants, morphology of Eu-NPs, crystal defect, phenomena like antenna effect and physical parameters like temperature. Through this review we explore and assimilate all the factors which affect the luminescence in Eu-NPs and coil a new thread of parameters that control the luminescence in Eu-NPs, which would provide further insight in developing Eu-based nanoprobes for future biomedical prospects. - Highlights: • The review describes 14 major factors that influence the luminescence properties of europium enabled luminescent nanoparticles (Eu-NPs). • Surveys different types of europium containing nanoparticles that have been reported for their biomedical applications. • Eu-NPs are conveniently divided into four different categories, based on the type of the substrates involved. The four categories are (1) virgin Eu-substrate based NPs; (2

  5. Experimental Performance Study of a High Speed Oil Lubricated Polymer Thrust Bearing

    Directory of Open Access Journals (Sweden)

    Jie Zhou

    2015-01-01

    Full Text Available With the demand for turbomachinery to operate at higher speeds, loads, and power, fluid film bearings that support turbomachinery must be capable of operating in these more demanding applications. Thrust bearings operating at high speeds and loads can experience high surface temperatures and thin fluid film thickness. Typically, babbitt (white metal is the bearing lining material for most turbomachinery bearings but is limited in operating temperature and allowable film thickness. Polymer based materials are alternative materials that can operate at high temperatures and with thin films and have been in use for many decades in high load applications, such as electric submersible pumps (ESP. Test results of polymer lined thrust bearings subjected to modern turbomachinery speeds and loads are presented and compared to babbitt lined bearings of the same design and under similar conditions. The test results show polymer lined thrust bearings can operate at higher bearing unit loads than babbitt.

  6. Synthesis and chemical recycling of high polymers using C1 compounds; C1 kagobutsu ni yoru kobunshi no chemical recycle

    Energy Technology Data Exchange (ETDEWEB)

    Masuda, T. [National Institute of Materials and Chemical Research, Tsukuba (Japan)

    1997-09-01

    The paper outlined a study of the synthesis of high polymers using C1 compounds which are continuously usable chemical materials and the related compounds such as the derivatives, and also the chemical recycle. In the case of waste plastics mixed in urban refuse, effective is the chemical recycle where C1 compounds obtained by gasifying the mixed waste are used as high polymer material. For the synthesis and recycle of high polymers using C1 compounds, there are three routes: Route A (recycle via high polymer materials), Route B (recycle via C1 compounds and high polymer materials), and Route C including global-scale carbon recycle (recycle via carbon dioxide from biodegradable plastics using microorganism). Among high polymers, those that can be synthesized from C1 compounds, for example, polymethylene, polyacetal and polyketone can be chemically recycled by Route B. 30 refs., 2 figs., 1 tab.

  7. Highly luminescent core-shell InP/ZnX (X = S, Se) quantum dots prepared via a phosphine synthetic route.

    Science.gov (United States)

    Mordvinova, Natalia; Vinokurov, Alexander; Kuznetsova, Tatiana; Lebedev, Oleg I; Dorofeev, Sergey

    2017-01-24

    Here we report a simple method for the creation of highly luminescent core-shell InP/ZnX (X = S, Se) quantum dots (QDs) on the basis of a phosphine synthetic route. In this method a Zn precursor was added to the reaction mixture at the beginning of the synthesis to form an In(Zn)P alloy structure, which promoted the formation of a ZnX shell. Core-shell InP/ZnX QDs exhibit highly intensive emission with a quantum yield over 50%. The proposed method is primarily important for practical applications. Advantages of this method compared to the widely used SILAR technique are discussed. We further demonstrate that the SILAR approach consisting of consequent addition of Zn and chalcogen precursors to pre-prepared non-doped InP colloidal nanoparticles is not quite suitable for shell growth without the addition of special activator agents or the use of very reactive precursors.

  8. gamma. -relaxation process in crystallizable polymers

    Energy Technology Data Exchange (ETDEWEB)

    Mindiyarov, Kh G; Zelenev, Yu V; Bartenev, G M [Birskij Gosudarstvennyj Pedagogicheskij Inst. (USSR)

    1975-07-01

    In the present paper, with the aid of radiothermoluminescence technique ..gamma..-relaxation processes are investigated, which are conditioned by molecular mobility and are associated with defects in the crystalline structure of polymers PEh, PP, and elastomers PIB, NK, SKD, SKI exposed to ..gamma..-rays of Co/sup 60/ at a dose rate of 1 Mrad. The shape of the thermoluminescence curve, i.e. the luminescence intensity in the ..cap alpha.. - ..gamma..-maxima, their relationship, position with respect to temperature are strongly dependent on the degree of crystallinity, on the thermal and mechanical prehistory. In highly crystalline samples of PEh and PP ..cap alpha..-maximum may be absent. Dependence has been studied of the luminescence intensity in the ..cap alpha..- and ..gamma..-maxima (Isub(..cap alpha..)/Isub(..gamma..)) on the crystallization temperature; the curve passes through the minimum when the crystallization rate is maximum. The relationship Isub(..gamma..)re of crystallinity degree.

  9. Significantly High Thermal Rectification in an Asymmetric Polymer Molecule Driven by Diffusive versus Ballistic Transport.

    Science.gov (United States)

    Ma, Hao; Tian, Zhiting

    2018-01-10

    Tapered bottlebrush polymers have novel nanoscale polymer architecture. Using nonequilibrium molecular dynamics simulations, we showed that these polymers have the unique ability to generate thermal rectification in a single polymer molecule and offer an exceptional platform for unveiling different heat conduction regimes. In sharp contrast to all other reported asymmetric nanostructures, we observed that the heat current from the wide end to the narrow end (the forward direction) in tapered bottlebrush polymers is smaller than that in the opposite direction (the backward direction). We found that a more disordered to less disordered structural transition within tapered bottlebrush polymers is essential for generating nonlinearity in heat conduction for thermal rectification. Moreover, the thermal rectification ratio increased with device length, reaching as high as ∼70% with a device length of 28.5 nm. This large thermal rectification with strong length dependence uncovered an unprecedented phenomenon-diffusive thermal transport in the forward direction and ballistic thermal transport in the backward direction. This is the first observation of radically different transport mechanisms when heat flow direction changes in the same system. The fundamentally new knowledge gained from this study can guide exciting research into nanoscale organic thermal diodes.

  10. Solution-processable ambipolar diketopyrrolopyrrole-selenophene polymer with unprecedentedly high hole and electron mobilities.

    Science.gov (United States)

    Lee, Junghoon; Han, A-Reum; Kim, Jonggi; Kim, Yiho; Oh, Joon Hak; Yang, Changduk

    2012-12-26

    There is a fast-growing demand for polymer-based ambipolar thin-film transistors (TFTs), in which both n-type and p-type transistor operations are realized in a single layer, while maintaining simplicity in processing. Research progress toward this end is essentially fueled by molecular engineering of the conjugated backbones of the polymers and the development of process architectures for device fabrication, which has recently led to hole and electron mobilities of more than 1.0 cm(2) V(-1) s(-1). However, ambipolar polymers with even higher performance are still required. By taking into account both the conjugated backbone and side chains of the polymer component, we have developed a dithienyl-diketopyrrolopyrrole (TDPP) and selenophene containing polymer with hybrid siloxane-solubilizing groups (PTDPPSe-Si). A synergistic combination of rational polymer backbone design, side-chain dynamics, and solution processing affords an enormous boost in ambipolar TFT performance, resulting in unprecedentedly high hole and electron mobilities of 3.97 and 2.20 cm(2) V(-1) s(-1), respectively.

  11. Liquid immersion thermal crosslinking of 3D polymer nanopatterns for direct carbonisation with high structural integrity

    Science.gov (United States)

    Kang, Da-Young; Kim, Cheolho; Park, Gyurim; Moon, Jun Hyuk

    2015-12-01

    The direct pyrolytic carbonisation of polymer patterns has attracted interest for its use in obtaining carbon materials. In the case of carbonisation of nanopatterned polymers, the polymer flow and subsequent pattern change may occur in order to relieve their high surface energies. Here, we demonstrated that liquid immersion thermal crosslinking of polymer nanopatterns effectively enhanced the thermal resistance and maintained the structure integrity during the heat treatment. We employed the liquid immersion thermal crosslinking for 3D porous SU8 photoresist nanopatterns and successfully converted them to carbon nanopatterns while maintaining their porous features. The thermal crosslinking reaction and carbonisation of SU8 nanopatterns were characterised. The micro-crystallinity of the SU8-derived carbon nanopatterns was also characterised. The liquid immersion heat treatment can be extended to the carbonisation of various polymer or photoresist nanopatterns and also provide a facile way to control the surface energy of polymer nanopatterns for various purposes, for example, to block copolymer or surfactant self-assemblies.

  12. Entropy driven spontaneous formation of highly porous films from polymer-nanoparticle composites

    International Nuclear Information System (INIS)

    Korampally, Venumadhav; Yun, Minseong; Rajagopalan, Thiruvengadathan; Gangopadhyay, Keshab; Gangopadhyay, Shubhra; Dasgupta, Purnendu K

    2009-01-01

    Nanoporous materials have become indispensable in many fields ranging from photonics, catalysis and semiconductor processing to biosensor infrastructure. Rapid and energy efficient process fabrication of these materials is, however, nontrivial. In this communication, we describe a simple method for the rapid fabrication of these materials from colloidal dispersions of Polymethyl Silsesquioxane nanoparticles. Nanoparticle-polymer composites above the decomposition temperature of the polymer are examined and the entropic gain experienced by the nanoparticles in this rubric is harnessed to fabricate novel highly porous films composed of nanoparticles. Optically smooth, hydrophobic films with low refractive indices (as low as 1.048) and high surface areas (as high as 1325 m 2 g -1 ) have been achieved with this approach. In this communication we address the behavior of such systems that are both temperature and substrate surface energy dependent. The method is applicable, in principle, to a variety of nanoparticle-polymer systems to fabricate custom nanoporous materials.

  13. High actuation properties of shape memory polymer composite actuator

    International Nuclear Information System (INIS)

    Basit, A; L’Hostis, G; Durand, B

    2013-01-01

    The shape memory polymers (SMPs) possess two shapes: permanent shape and temporary shape. This property leads to replacement of shape memory alloys by SMPs in various applications. In this work, two properties, namely structure activeness and the shape memory property of ‘controlled behavior composite material (CBCM)’ plate and its comparison with the conventional symmetrical composite plate (SYM), are studied. The SMPC plates (CBCM and SYM) are manufactured using epoxy resin with a thermal glass transition temperature (T g ) of 130 °C. The shape memory properties of these composites are investigated (under three-point bending test) and compared by deforming them to the same displacement. Three types of recoveries are conducted: unconstrained recovery, constrained recovery, and partial recovery under load. It is found that by coupling the structure activeness (due to its asymmetry) and its shape memory property, higher activated displacement is obtained during the unconstrained recovery. Also, at a lower recovery temperature (90 °C) than the fixing temperature, a recovery close to 100% is obtained for CBCM, whereas for SYM it is only 25%. During constrained recovery, CBCM produces five times larger recovery force than SYM. In addition, higher actuation properties are demonstrated by calculating recovered work and recovery percentages during partial recovery under load. (paper)

  14. Electrostatic probes in luminescent discharges

    International Nuclear Information System (INIS)

    Cunha Raposo, C. da.

    1980-01-01

    A system to produce luminescent type plasma by continuos discharge and ionization by high frequency was constructed. The ionization was done in the air and in the argon under pressures from 3 to 10 mmHg. The parameters of a non magnetized collisional plasma and the parameters of a magnetized plasma such as, density, eletron temperature and potential, using a Langmuir probe with plane geometry, were determined. (M.C.K.) [pt

  15. Highly efficient inverted polymer solar cells based on a cross-linkable water-/alcohol-soluble conjugated polymer interlayer.

    Science.gov (United States)

    Zhang, Kai; Zhong, Chengmei; Liu, Shengjian; Mu, Cheng; Li, Zhengke; Yan, He; Huang, Fei; Cao, Yong

    2014-07-09

    A cross-linkable water/alcohol soluble conjugated polymer (WSCP) material poly[9,9-bis(6'-(N,N-diethylamino)propyl)-fluorene-alt-9,9-bis(3-ethyl(oxetane-3-ethyloxy)-hexyl) fluorene] (PFN-OX) was designed. The cross-linkable nature of PFN-OX is good for fabricating inverted polymer solar cells (PSCs) with well-defined interface and investigating the detailed working mechanism of high-efficiency inverted PSCs based on poly[4,8-bis(2-ethylhexyloxyl)benzo[1,2-b:4,5-b']dithio-phene-2,6-diyl-alt-ethylhexyl-3-fluorothithieno[3,4-b]thiophene-2-carboxylate-4,6-diyl] (PTB7) and (6,6)-phenyl-C71-butyric acid methyl ester (PC71BM) blend active layer. The detailed working mechanism of WSCP materials in high-efficiency PSCs were studied and can be summarized into the following three effects: a) PFN-OX tunes cathode work function to enhance open-circuit voltage (Voc); b) PFN-OX dopes PC71BM at interface to facilitate electron extraction; and c) PFN-OX extracts electrons and blocks holes to enhance fill factor (FF). On the basis of this understanding, the hole-blocking function of the PFN-OX interlayer was further improved with addition of a ZnO layer between ITO and PFN-OX, which led to inverted PSCs with a power conversion efficiency of 9.28% and fill factor high up to 74.4%.

  16. Luminescence and scintillation of Ce.sup.3+./sup.-doped oxide glass with high Gd.sub.2./sub.O.sub.3./sub. concentration

    Czech Academy of Sciences Publication Activity Database

    Chewpraditkul, W.; He, X.; Chen, D.; Shen, Y.; Sheng, Q.; Yu, B.; Nikl, Martin; Kučerková, Romana; Beitlerová, Alena; Wanarak, C.; Phunpueok, A.

    2011-01-01

    Roč. 208, č. 12 (2011), s. 2830-2832 ISSN 1862-6300 R&D Projects: GA MŠk(CZ) ME10084 Institutional research plan: CEZ:AV0Z10100521 Keywords : Ce 3+ * light yield * luminescence * oxide glasses * scintillation * time-resolved luminescence Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.463, year: 2011

  17. Luminescence of high density electron-hole plasma in CdS and CdSe in a wide temperature range

    International Nuclear Information System (INIS)

    Yoshida, H.; Shionoya, S.

    1983-01-01

    Time-resolved spectra of the spontaneous luminescence of the high density electron-hole plasma (EHP) in CdS and CdSe are observed in a wide range of temperature which is surely higher than the calculated critical temperature for electron-hole liquid formation, in order to carry forward discussion on dynamic nature of the EHP previously observed in 4.2 K experiments. Spectra in the late stage are analyzed, and obtained values of the reduced bandgap energy and chemical potential are compared with those theoretically calculated for higher temperatures. The aspects of the change of the spectral shape in the late stage are hard to understand. Unfortunately no clear conclusion is drawn on the nature of the EHP produced at 4.2 K. The only thing one can say is that the condensed electron-hole liquid state, which is in equilibrium with the exciton state, is not realized. (author)

  18. 1,2,4-Triazines in the Synthesis of Bipyridine Bisphenolate ONNO Ligands and Their Highly Luminescent Tetradentate Pt(II) Complexes for Solution-Processable OLEDs.

    Science.gov (United States)

    Pander, Piotr; Bulmer, Rachel; Martinscroft, Ross; Thompson, Stuart; Lewis, Frank W; Penfold, Thomas J; Dias, Fernando B; Kozhevnikov, Valery N

    2018-04-02

    This article describes a convenient method for the synthesis of ONNO-type tetradentate 6,6'-bis(2-phenoxy)-2,2'-bipyridine (bipyridine bisphenolate, BpyBph) ligands and their platinum(II) complexes. The methodology includes the synthesis of 1,2,4-triazine precursors followed by their transformation to functionalized pyridines by the Boger reaction. Two complementary routes employing 3,3'- and 5,5'-bis-triazines allow a modification of the central pyridine rings in different positions, which was exemplified by the introduction of cyclopentene rings. The new ligands were used to prepare highly luminescent ONNO-type Pt(II) complexes. The position of the cyclopentene rings significantly influences the solubility and photophysical properties of these complexes. Derivatives with closely positioned cyclopentene rings are soluble in organic solvents and proved to be the best candidate for solution-processable organic light-emitting devices (OLEDs), showing efficient single-dopant candlelight electroluminescence.

  19. Polymer waveguides for electro-optical integration in data centers and high-performance computers.

    Science.gov (United States)

    Dangel, Roger; Hofrichter, Jens; Horst, Folkert; Jubin, Daniel; La Porta, Antonio; Meier, Norbert; Soganci, Ibrahim Murat; Weiss, Jonas; Offrein, Bert Jan

    2015-02-23

    To satisfy the intra- and inter-system bandwidth requirements of future data centers and high-performance computers, low-cost low-power high-throughput optical interconnects will become a key enabling technology. To tightly integrate optics with the computing hardware, particularly in the context of CMOS-compatible silicon photonics, optical printed circuit boards using polymer waveguides are considered as a formidable platform. IBM Research has already demonstrated the essential silicon photonics and interconnection building blocks. A remaining challenge is electro-optical packaging, i.e., the connection of the silicon photonics chips with the system. In this paper, we present a new single-mode polymer waveguide technology and a scalable method for building the optical interface between silicon photonics chips and single-mode polymer waveguides.

  20. Luminescence studies of molecular materials

    International Nuclear Information System (INIS)

    Miller, P.F.

    2000-01-01

    Molecular materials have been widely studied for their potential uses in novel semiconductor devices. They occupy the intellectually interesting area between molecular and bulk descriptions of matter, and as such often have unique and useful characteristics. The design and engineering of these structures is inter-disciplinary in its nature, embracing the fields of physics, electrical engineering and both synthetic and physical chemistry. In this thesis luminescence studies of molecular materials will be presented that probe the nature of the excited states in two promising semiconductor systems. Luminescence techniques provide a powerful and sensitive tool in the investigation of kinetic pathways of radiative and non-radiative emission from these samples. This is particularly appropriate here, as the materials being studied are of potential use in electroluminescent devices. The suitability of photoluminescence techniques comes from both the electroluminescence and photoluminescence sharing the same emitting state. The first class of material studied here is an organic semiconducting polymer, cyano-substituted polyphenylenevinylene (CN-PPV). Conjugated polymers combine semiconducting electronic properties with favourable processing properties and offer the possibility of tuning their optical and electronic properties chemically. The cyanosubstitution increases the electron affinity of the polymer backbone, facilitating electron injection in light-emitting diodes. The polymers are soluble in solvents such as toluene and chloroform due the presence of alkoxy sidegroups. CdSe semiconductor nanocrystals are the other class of material characterised in this work. Semiconductor nanocrystals exhibit interesting size-tunable optical properties due to the confinement of the electronic wave functions. Characterisation of samples produced by different synthetic routes has been carried out to demonstrate the advantages of a novel synthetic method in terms of physical and

  1. High-Throughput Fabrication of Nanocone Substrates through Polymer Injection Moulding For SERS Analysis in Microfluidic Systems

    DEFF Research Database (Denmark)

    Viehrig, Marlitt; Matteucci, Marco; Thilsted, Anil H.

    analysis. Metal-capped silicon nanopillars, fabricated through a maskless ion etch, are state-of-the-art for on-chip SERS substrates. A dense cluster of high aspect ratio polymer nanocones was achieved by using high-throughput polymer injection moulding over a large area replicating a silicon nanopillar...... structure. Gold-capped polymer nanocones display similar SERS sensitivity as silicon nanopillars, while being easily integrable into a microfluidic chips....

  2. Investigation of polymer derived ceramics cantilevers for application of high speed atomic force microscopy

    Science.gov (United States)

    Wu, Chia-Yun

    High speed Atomic Force Microscopy (AFM) has a wide variety of applications ranging from nanomanufacturing to biophysics. In order to have higher scanning speed of certain AFM modes, high resonant frequency cantilevers are needed; therefore, the goal of this research is to investigate using polymer derived ceramics for possible applications in making high resonant frequency AFM cantilevers using complex cross sections. The polymer derived ceramic that will be studied, is silicon carbide. Polymer derived ceramics offer a potentially more economic fabrication approach for MEMS due to their relatively low processing temperatures and ease of complex shape design. Photolithography was used to make the desired cantilever shapes with micron scale size followed by a wet etching process to release the cantilevers from the substrates. The whole manufacturing process we use borrow well-developed techniques from the semiconducting industry, and as such this project also could offer the opportunity to reduce the fabrication cost of AFM cantilevers and MEMS in general. The characteristics of silicon carbide made from the precursor polymer, SMP-10 (Starfire Systems), were studied. In order to produce high qualities of silicon carbide cantilevers, where the major concern is defects, proper process parameters needed to be determined. Films of polymer derived ceramics often have defects due to shrinkage during the conversion process. Thus control of defects was a central issue in this study. A second, related concern was preventing oxidation; the polymer derived ceramics we chose is easily oxidized during processing. Establishing an environment without oxygen in the whole process was a significant challenge in the project. The optimization of the parameters for using photolithography and wet etching process was the final and central goal of the project; well established techniques used in microfabrication were modified for use in making the cantilever in the project. The techniques

  3. Plasmon-enhanced optically stimulated luminescence

    Energy Technology Data Exchange (ETDEWEB)

    Guidelli, E. J.; Baffa, O. [Universidade de Sao Paulo, Faculdade de Filosofia, Ciencias e Letras de Ribeirao Preto, Departamento de Fisica, Av. Bandeirantes 3900, 14040-901 Ribeirao Preto, Sao Paulo (Brazil); Ramos, A. P., E-mail: ederguidelli@gmail.com [Universidade de Sao Paulo, Faculdade de Filosofia, Ciencias e Letras de Ribeirao Preto, Departamento de Quimica, Av. Bandeirantes 3900, 14040-901 Ribeirao Preto, Sao Paulo (Brazil)

    2015-10-15

    Full text: Optically Stimulated Luminescence dosimeters (OSLD) have been largely used for personal, medical, and industrial radiation dosimetry. Developing highly sensitive and small-sized radiation detectors and dosimeters is essential for improving spatial resolution and consequently diagnosis quality and treatment efficacy in the case of applications in radiodiagnosis and radiation therapy, for instance. Conventional methods to improve the OSLD sensitivity consist of doping and co-doping the host materials with atoms of other elements, thereby increasing the amount of trapping and/or luminescent centers. Our group is researching on the use of the plasmon properties of noble metal nanoparticles to increase OSL intensity. Upon incidence of a light beam with appropriate resonant wavelengths, the oscillation of the free electrons at the nanoparticle surface originates the Localized Surface Plasmons (LSP) and the consequent plasmon resonance band. The interaction between the LSP and the surrounding luminescent material leads to new optical properties largely employed for enhancing several luminescent processes. Here we will show our results regarding the use of LSP to increase OSLD sensitivity. The interaction between the traps/luminescent centers and the plasmons depends on the distance between them, on the plasmon resonance band intensity and position, as well as on the surrounding medium. Therefore, the plasmon-enhanced luminescence is a promising tool to develop more sensitive and miniaturized OSLD. (Author)

  4. Plasmon-enhanced optically stimulated luminescence

    International Nuclear Information System (INIS)

    Guidelli, E. J.; Baffa, O.; Ramos, A. P.

    2015-10-01

    Full text: Optically Stimulated Luminescence dosimeters (OSLD) have been largely used for personal, medical, and industrial radiation dosimetry. Developing highly sensitive and small-sized radiation detectors and dosimeters is essential for improving spatial resolution and consequently diagnosis quality and treatment efficacy in the case of applications in radiodiagnosis and radiation therapy, for instance. Conventional methods to improve the OSLD sensitivity consist of doping and co-doping the host materials with atoms of other elements, thereby increasing the amount of trapping and/or luminescent centers. Our group is researching on the use of the plasmon properties of noble metal nanoparticles to increase OSL intensity. Upon incidence of a light beam with appropriate resonant wavelengths, the oscillation of the free electrons at the nanoparticle surface originates the Localized Surface Plasmons (LSP) and the consequent plasmon resonance band. The interaction between the LSP and the surrounding luminescent material leads to new optical properties largely employed for enhancing several luminescent processes. Here we will show our results regarding the use of LSP to increase OSLD sensitivity. The interaction between the traps/luminescent centers and the plasmons depends on the distance between them, on the plasmon resonance band intensity and position, as well as on the surrounding medium. Therefore, the plasmon-enhanced luminescence is a promising tool to develop more sensitive and miniaturized OSLD. (Author)

  5. Preparation and characterization of high performance Schiff-base liquid crystal diepoxide polymer

    International Nuclear Information System (INIS)

    Liu Huan; Fu Zien; Xu Kai; Cai Hualun; Liu Xin; Chen Mingcai

    2012-01-01

    Graphical abstract: The specific effects of highly conjugated Schiff-base moiety on thermal properties of the Schiff-base epoxy polymer were proposed first by us. From the point of view of structure-properties relationship, it can be considered that owing to the presence of the Schiff-base group, the high performance liquid crystal diepoxide polymer displayed improved thermal stability. Highlights: ► In this work, we first proposed that specific effects of highly conjugated Schiff-base moiety on thermal properties of the Schiff-base epoxy polymer. ► As one aim of this study, the thermal and thermal-oxidative stabilities of the thermosets were studied by TGA under nitrogen and under air. ► The second aim of this study was to further understand the thermal degradation mechanism. ► For thermal degradation mechanism of this polymer under nitrogen, TG-IR was used to investigate volatile components, and SEM/EDS was used to explore morphologies and chemical components of the residual char. ► From the point of view of structure-properties relationship, it can be considered that owing to the presence of the Schiff-base group, the high performance liquid crystal diepoxide polymer displayed the improved thermal stability. - Abstract: A novel Schiff-base liquid crystal diepoxide polymer was prepared via a thermal copolymerization of a Schiff-base epoxy monomer (PBMBA) with a diamine co-monomer (MDA). We first proposed that specific effects of highly conjugated Schiff-base moiety on thermal properties of the Schiff-base epoxy polymer (PBMBA/MDA). Thermal degradation behavior of the polymer was characterized using thermogravimetric analysis (TGA) under nitrogen and under air, respectively. Thermogravimetric data obtained from TGA under nitrogen and under air reveal that PBMBA/MDA exhibits higher thermal stability compared with bisphenol-A type epoxy polymer (DGEBA/MDA) and other mesogene-containing epoxy polymer. It is worth pointing out that the outstanding residual

  6. Near-Infrared Quantum Cutting Long Persistent Luminescence

    OpenAIRE

    Zou, Zehua; Feng, Lin; Cao, Cheng; Zhang, Jiachi; Wang, Yuhua

    2016-01-01

    By combining the unique features of the quantum cutting luminescence and long persistent luminescence, we design a new concept called ?near-infrared quantum cutting long persistent luminescence (NQPL)?, which makes it possible for us to obtain highly efficient (>100%) near-infrared long persistent luminescence in theory. Guided by the NQPL concept, we fabricate the first NQPL phosphor Ca2Ga2GeO7:Pr3+,Yb3+. It reveals that both the two-step energy transfer of model (I) and the one-step energy ...

  7. VARTM Processing of High Temperature Polymer Matrix Composites

    National Research Council Canada - National Science Library

    Criss, Jr, Jim M

    2008-01-01

    The overall technical objective of the Phase 1 effort was to extend and advance the state the-art in high temperature composite fabrication techniques by developing a High Tempera Vacuum Assisted Resin Transfer Molding (VARTM...

  8. High Temperature Degradation Mechanisms in Polymer Matrix Composites

    Science.gov (United States)

    Cunningham, Ronan A.

    1996-01-01

    Polymer matrix composites are increasingly used in demanding structural applications in which they may be exposed to harsh environments. The durability of such materials is a major concern, potentially limiting both the integrity of the structures and their useful lifetimes. The goal of the current investigation is to develop a mechanism-based model of the chemical degradation which occurs, such that given the external chemical environment and temperatures throughout the laminate, laminate geometry, and ply and/or constituent material properties, we can calculate the concentration of diffusing substances and extent of chemical degradation as functions of time and position throughout the laminate. This objective is met through the development and use of analytical models, coupled to an analysis-driven experimental program which offers both quantitative and qualitative information on the degradation mechanism. Preliminary analyses using a coupled diffusion/reaction model are used to gain insight into the physics of the degradation mechanisms and to identify crucial material parameters. An experimental program is defined based on the results of the preliminary analysis which allows the determination of the necessary material coefficients. Thermogravimetric analyses are carried out in nitrogen, air, and oxygen to provide quantitative information on thermal and oxidative reactions. Powdered samples are used to eliminate diffusion effects. Tests in both inert and oxidative environments allow the separation of thermal and oxidative contributions to specimen mass loss. The concentration dependency of the oxidative reactions is determined from the tests in pure oxygen. Short term isothermal tests at different temperatures are carried out on neat resin and unidirectional macroscopic specimens to identify diffusion effects. Mass loss, specimen shrinkage, the formation of degraded surface layers and surface cracking are recorded as functions of exposure time. Geometry effects

  9. High-Throughput” Evaluation of Polymer-Supported Triazolic Appendages for Metallic Cations Extraction

    Directory of Open Access Journals (Sweden)

    Riadh Slimi

    2015-03-01

    Full Text Available The aim of this work was to find and use a low-cost high-throughput method for a quick primary evaluation of several metal extraction by substituted piperazines appendages as chelatants grafted onto Merrifield polymer using click-chemistry by the copper (I-catalyzed Huisgen’s reaction (CuAAC The polymers were tested for their efficiency to remove various metal ions from neutral aqueous solutions (13 cations studied: Li+, Na+, K+, Mn2+, Fe3+, Co2+, Ni2+, Cu2+, Cd2+, Ba2+, Ce3+, Hg+ and Pb2+ using the simple conductimetric measurement method. The polymers were found to extract all metals with low efficiencies ≤40%, except for Fe3+ and Hg+, and sometimes Pb2+. Some polymers exhibited a selectively for K+, Cd2+ and Ba2+, with good efficiencies. The values obtained here using less polymer, and a faster method, are in fair correspondence (average difference ±16% with another published evaluation by atomic absorption spectroscopy (AAS.

  10. High resolution optical spectroscopy of air-induced electrical instabilities in n-type polymer semiconductors.

    Science.gov (United States)

    Di Pietro, Riccardo; Sirringhaus, Henning

    2012-07-03

    We use high-resolution charge-accumulation optical spectroscopy to measure charge accumulation in the channel of an n-type organic field-effect transistor. We monitor the degradation of device performance in air, correlate the onset voltage shift with the reduction of charge accumulated in the polymer semiconductor, and explain the results in view of the redox reaction between the polymer, water and oxygen in the accumulation layer. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Fast prototyping of conducting polymer microelectrodes using resistance-controlled high precision drilling

    DEFF Research Database (Denmark)

    Kafka, Jan Robert; Geschke, Oliver; Skaarup, Steen

    2011-01-01

    We present a straightforward method for fast prototyping of microelectrode arrays in the highly conductive polymer poly(3,4-ethylenedioxythiophene) (PEDOT). Microelectrode arrays were produced by electrical resistance-controlled microdrilling through an insulating polymer layer (TOPAS® 5013...... approach the steady state currents predicted from modeling, but at a much slower rate than expected. This is shown to be caused by the use of electroactive PEDOT electrodes. Subtraction of the latter contribution gives approach to steady state currents within a few seconds, which is in very good agreement...

  12. A possible recycling method for high grade steels EAFD in polymer composites.

    Science.gov (United States)

    Niubó, M; Fernández, A I; Chimenos, J M; Haurie, L

    2009-11-15

    This work evaluates the feasibility of incorporating electric arc furnace dust (EAFD), as filler in a polymer matrix, to obtain a moldable heavyweight sheet, useful for acoustic insulation in automotive industry. For this purpose EAFD from a steel factory that manufactures high quality steels, was characterized and different formulations of composites were prepared. Physical and mechanical properties, as well as fire behaviour were tested and compared with a polymer composite compounded with common mineral fillers. Optimum formulation with 25% EAFD fulfils the RoHs Directive used by automotive industry to regulate heavy metals content. Leaching test was also performed on prepared composites to classify the material after use.

  13. Small-bandgap semiconducting polymers with high near-infrared photoresponse

    NARCIS (Netherlands)

    Hendriks, K.H.; Li, W.; Wienk, M.M.; Janssen, R.A.J.

    2014-01-01

    Lowering the optical bandgap of conjugated polymers while maintaining a high efficiency for photoinduced charge transfer to suitable electron acceptors such as fullerene has remained a formidable challenge in the area of organic photovoltaics. Here we present the synthesis and application of a

  14. High quality ion channels recordings on an injection molded polymer chip

    DEFF Research Database (Denmark)

    Tanzi, Simone

    In this thesis we demonstrate high quality recordings of the ion channel activity across the cell membrane in a biological cell by employing the so called patch clamping technique on an injection molded polymer microfluidic device. Such recordings are traditionally made using glass micropipettes,...

  15. Polybenzimidazole and sulfonated polyhedral oligosilsesquioxane composite membranes for high temperature polymer electrolyte membrane fuel cells

    DEFF Research Database (Denmark)

    Aili, David; Allward, Todd; Alfaro, Silvia Martinez

    2014-01-01

    Composite membranes based on poly(2,2′(m-phenylene)-5,5́bibenzimidazole) (PBI) and sulfonated polyhedral oligosilsesquioxane (S-POSS) with S-POSS contents of 5 and 10wt.% were prepared by solution casting as base materials for high temperature polymer electrolyte membrane fuel cells. With membranes...

  16. A new modified-serpentine flow field for application in high temperature polymer electrolyte fuel cell

    DEFF Research Database (Denmark)

    Singdeo, Debanand; Dey, Tapobrata; Gaikwad, Shrihari

    2017-01-01

    field design is proposed and its usefulness for the fuel cell applications are evaluated in a high-temperature polymer electrolyte fuel cell. The proposed geometry retains some of the features of serpentine flow field such as multiple bends, while modifications are made in its in-plane flow path...

  17. Label-free biosensing with high sensitivity in dual-core microstructured polymer optical fibers

    DEFF Research Database (Denmark)

    Markos, Christos; Yuan, Wu; Vlachos, Kyriakos

    2011-01-01

    We present experimentally feasible designs of a dual-core microstructured polymer optical fiber (mPOF), which can act as a highly sensitive, label-free, and selective biosensor. An immobilized antigen sensing layer on the walls of the holes in the mPOF provides the ability to selectively capture...

  18. High-throughput experimentation in synthetic polymer chemistry: From RAFT and anionic polymerizations to process development

    NARCIS (Netherlands)

    Guerrero-Sanchez, C.A.; Paulus, R.M.; Fijten, M.W.M.; Mar, de la M.J.; Hoogenboom, R.; Schubert, U.S.

    2006-01-01

    The application of combinatorial and high-throughput approaches in polymer research is described. An overview of the utilized synthesis robots is given, including different parallel synthesizers and a process development robot. In addition, the application of the parallel synthesis robots to

  19. High-quality graphene flakes exfoliated on a flat hydrophobic polymer

    DEFF Research Database (Denmark)

    Pedrinazzi, Paolo; Caridad, José M.; Mackenzie, David M. A.

    2018-01-01

    the environment of the graphene flake is completely changed, by encapsulating preselected flakes between hexagonal boron nitride layers. The exfoliation of clean, pristine graphene layers directly on flat polymer substrates enables high performance, supported, and non-encapsulated graphene devices for flexible...

  20. Positron-Induced Luminescence

    Science.gov (United States)

    Stenson, E. V.; Hergenhahn, U.; Stoneking, M. R.; Pedersen, T. Sunn

    2018-04-01

    We report on the observation that low-energy positrons incident on a phosphor screen produce significantly more luminescence than electrons do. For two different wide-band-gap semiconductor phosphors (ZnS:Ag and ZnO:Zn), we compare the luminescent response to a positron beam with the response to an electron beam. For both phosphors, the positron response is significantly brighter than the electron response, by a factor that depends strongly on incident energy (0-5 keV). Positrons with just a few tens of electron-volts of energy (for ZnS:Ag) or less (for ZnO:Zn) produce as much luminescence as is produced by electrons with several kilo-electron-volts. We attribute this effect to valence band holes and excited electrons produced by positron annihilation and subsequent Auger processes. These results demonstrate a valuable approach for addressing long-standing questions about luminescent materials.

  1. Catalysis and luminescence in mechanically activated polymers

    NARCIS (Netherlands)

    Jakobs, R.T.M.

    2013-01-01

    Mechanochemistry refers to chemical reactions that are induced by the direct absorption of mechanical energy. In this respect, mechanical energy can be seen as an alternative method of supplying energy to promote chemical reactions, alongside thermal energy, electrical energy and (photo)chemical

  2. High resolution scanning optical imaging of a frozen planar polymer light-emitting electrochemical cell: an experimental and modelling study

    Institute of Scientific and Technical Information of China (English)

    Faleh AlTal; Jun Gao

    2017-01-01

    Light-emitting electrochemical cells (LECs) are organic photonic devices based on a mixed electronic and ionic conductor.The active layer of a polymer-based LEC consists of a luminescent polymer,an ion-solvating/transport polymer,and a compatible salt.The LEC p-n or p-i-n junction is ultimately responsible for the LEC performance.The LEC junction,however,is still poorly understood due to the difficulties of characterizing a dynamic-junction LEC.In this paper,we present an experimental and modeling study of the LEC junction using scanning optical imaging techniques.Planar LECs with an interelectrode spacing of 560 μm have been fabricated,activated,frozen and scanned using a focused laser beam.The optical-beam-induced-current (OBIC) and photoluminescence (PL) data have been recorded as a function of beam location.The OBIC profile has been simulated in COMSOL that allowed for the determination of the doping concentration and the depletion width of the LEC junction.

  3. Vacuum-integrated electrospray deposition for highly reliable polymer thin film.

    Science.gov (United States)

    Park, Soohyung; Lee, Younjoo; Yi, Yeonjin

    2012-10-01

    Vacuum electrospray deposition (ESD) equipment was designed to prepare polymer thin films. The polymer solution can be injected directly into vacuum system through multi-stage pumping line, so that the solvent residues and ambient contaminants are highly reduced. To test the performance of ESD system, we fabricated organic photovoltaic cells (OPVCs) by injecting polymer solution directly onto the substrate inside a high vacuum chamber. The OPVC fabricated has the structure of Al∕P3HT:PCBM∕PEDOT:PSS∕ITO and was optimized by varying the speed of solution injection and concentration of the solution. The power conversion efficiency (PCE) of the optimized OPVC is 3.14% under AM 1.5G irradiation without any buffer layer at the cathode side. To test the advantages of the vacuum ESD, we exposed the device to atmosphere between the deposition steps of the active layer and cathode. This showed that the PCE of the vacuum processed device is 24% higher than that of the air exposed device and confirms the advantages of the vacuum prepared polymer film for high performance devices.

  4. High strength films from oriented, hydrogen-bonded "graphamid" 2D polymer molecular ensembles.

    Science.gov (United States)

    Sandoz-Rosado, Emil; Beaudet, Todd D; Andzelm, Jan W; Wetzel, Eric D

    2018-02-27

    The linear polymer poly(p-phenylene terephthalamide), better known by its tradename Kevlar, is an icon of modern materials science due to its remarkable strength, stiffness, and environmental resistance. Here, we propose a new two-dimensional (2D) polymer, "graphamid", that closely resembles Kevlar in chemical structure, but is mechanically advantaged by virtue of its 2D structure. Using atomistic calculations, we show that graphamid comprises covalently-bonded sheets bridged by a high population of strong intermolecular hydrogen bonds. Molecular and micromechanical calculations predict that these strong intermolecular interactions allow stiff, high strength (6-8 GPa), and tough films from ensembles of finite graphamid molecules. In contrast, traditional 2D materials like graphene have weak intermolecular interactions, leading to ensembles of low strength (0.1-0.5 GPa) and brittle fracture behavior. These results suggest that hydrogen-bonded 2D polymers like graphamid would be transformative in enabling scalable, lightweight, high performance polymer films of unprecedented mechanical performance.

  5. NanoComposite Polymers for High Resolution Near Infrared Detectors

    Data.gov (United States)

    National Aeronautics and Space Administration — Develop nanocomposite materials with tuned refractive index in the near infra red spectral range as an index-matched immersion lens for high resolution infra-red...

  6. A thin layer fiber-coupled luminescence dosimeter based on Al2O3:C

    DEFF Research Database (Denmark)

    Klein, F.A.; Greilich, Steffen; Andersen, Claus Erik

    2011-01-01

    In this paper we present a fiber-coupled luminescent Al2O3:C dosimeter probe with high spatial resolution (0.1 mm). It is based on thin layers of Al2O3:C crystal powder and a UV-cured acrylate monomer composition. The fabrication of the thin layers is described in detail. No influence of the intr......In this paper we present a fiber-coupled luminescent Al2O3:C dosimeter probe with high spatial resolution (0.1 mm). It is based on thin layers of Al2O3:C crystal powder and a UV-cured acrylate monomer composition. The fabrication of the thin layers is described in detail. No influence...... of the introduced polymer host matrix on the dosimetric properties was observed. Depth-dose measurements with the new detectors in a 142.66 MeV proton and 270.55 MeV/u carbon ion beam are presented as example applications. We used an RL protocol with saturated crystals allowing for time-effective measurements...... without sensitivity corrections. For protons, a relative luminescence efficiency hHCP of 0.715 0.014 was found in the Bragg peak. For carbon ions, a value of 0.498 0.001 was found in the entrance channel, 0.205 0.015 in the Bragg peak, and a mean of 0.413 0.050 in the tail region. The mean range...

  7. Thieno[3,4-c]Pyrrole-4,6-Dione-Based Polymer Acceptors for High Open-Circuit Voltage All-Polymer Solar Cells

    KAUST Repository

    Liu, Shengjian

    2017-04-20

    While polymer acceptors are promising fullerene alternatives in the fabrication of efficient bulk heterojunction (BHJ) solar cells, the range of efficient material systems relevant to the “all-polymer” BHJ concept remains narrow, and currently limits the perspectives to meet the 10% efficiency threshold in all-polymer solar cells. This report examines two polymer acceptor analogs composed of thieno[3,4-c]pyrrole-4,6-dione (TPD) and 3,4-difluorothiophene ([2F]T) motifs, and their BHJ solar cell performance pattern with a low-bandgap polymer donor commonly used with fullerenes (PBDT-TS1; taken as a model system). In this material set, the introduction of a third electron-deficient motif, namely 2,1,3-benzothiadiazole (BT), is shown to (i) significantly narrow the optical gap (Eopt) of the corresponding polymer (by ≈0.2 eV) and (ii) improve the electron mobility of the polymer by over two orders of magnitude in BHJ solar cells. In turn, the narrow-gap P2TPDBT[2F]T analog (Eopt = 1.7 eV) used as fullerene alternative yields high open-circuit voltages (VOC) of ≈1.0 V, notable short-circuit current values (JSC) of ≈11.0 mA cm−2, and power conversion efficiencies (PCEs) nearing 5% in all-polymer BHJ solar cells. P2TPDBT[2F]T paves the way to a new, promising class of polymer acceptor candidates.

  8. Ratiometric highly sensitive luminescent nanothermometers working in the room temperature range. Applications to heat propagation in nanofluids

    Science.gov (United States)

    Brites, Carlos D. S.; Lima, Patrícia P.; Silva, Nuno J. O.; Millán, Angel; Amaral, Vitor S.; Palacio, Fernando; Carlos, Luís D.

    2013-07-01

    There is an increasing demand for accurate, non-invasive and self-reference temperature measurements as technology progresses into the nanoscale. This is particularly so in micro- and nanofluidics where the comprehension of heat transfer and thermal conductivity mechanisms can play a crucial role in areas as diverse as energy transfer and cell physiology. Here we present two luminescent ratiometric nanothermometers based on a magnetic core coated with an organosilica shell co-doped with Eu3+ and Tb3+ chelates. The design of the hybrid host and chelate ligands permits the working of the nanothermometers in a nanofluid at 293-320 K with an emission quantum yield of 0.38 +/- 0.04, a maximum relative sensitivity of 1.5% K-1 at 293 K and a spatio-temporal resolution (constrained by the experimental setup) of 64 × 10-6 m/150 × 10-3 s (to move out of 0.4 K - the temperature uncertainty). The heat propagation velocity in the nanofluid, (2.2 +/- 0.1) × 10-3 m s-1, was determined at 294 K using the nanothermometers' Eu3+/Tb3+ steady-state spectra. There is no precedent of such an experimental measurement in a thermographic nanofluid, where the propagation velocity is measured from the same nanoparticles used to measure the temperature.There is an increasing demand for accurate, non-invasive and self-reference temperature measurements as technology progresses into the nanoscale. This is particularly so in micro- and nanofluidics where the comprehension of heat transfer and thermal conductivity mechanisms can play a crucial role in areas as diverse as energy transfer and cell physiology. Here we present two luminescent ratiometric nanothermometers based on a magnetic core coated with an organosilica shell co-doped with Eu3+ and Tb3+ chelates. The design of the hybrid host and chelate ligands permits the working of the nanothermometers in a nanofluid at 293-320 K with an emission quantum yield of 0.38 +/- 0.04, a maximum relative sensitivity of 1.5% K-1 at 293 K and a spatio

  9. Enhancing the efficiency of thiomers: Utilizing a highly mucoadhesive polymer as backbone for thiolation and preactivation.

    Science.gov (United States)

    Prüfert, Felix; Bonengel, Sonja; Menzel, Claudia; Bernkop-Schnürch, Andreas

    2017-01-01

    The objective of this study was to develop a novel thiomer with enhanced mucoadhesive properties using a highly mucoadhesive polymeric backbone. Fixomer™ A-30 (poly(methacrylic acid-co-sodium acrylamidomethyl propane sulfonate)), exhibiting a mucoadhesive strength superior to that of all other polymers, was thiolated by conjugation with l-cysteine and furthermore preactivated with 2-mercaptonicotinic acid (MNA). The resulting derivatives Fix-SH and Fix-S-MNA exhibited coupling rates of 755μmol thiol groups and 304μmol MNA per gram polymer, respectively. The mucoadhesive profile was evaluated with three different methods: tensile studies, rotating cylinder and rheological synergism. In tensile studies, a total work of adhesion of above 500μJ was determined for the unmodified polymer that increased to around 750μJ after thiolation and around 1500μJ after preactivation. The adhesion time of Fix-SH on the rotating cylinder was 3.7-fold and that of Fix-S-MNA 6.8-fold longer compared to the unmodified polymer. A rheological synergism was observed for the unmodified polymer as well as the derivatives with a non-significant difference for Fix-SH but a 5.44-fold improvement for Fix-S-MNA. Fix-S-MNA showed a significantly improved swelling behavior with a water-uptake up to the 30-fold of its initial weight over >50h whereas thiolation showed only slight improvements. Derivatization had no significant influence on cell viability. According to the results, Fix-S-MNA seems to be a suitable polymer for mucoadhesive drug delivery systems. Copyright © 2016. Published by Elsevier B.V.

  10. Processing and Characterization of Basalt Fiber Reinforced Ceramic Composites for High Temperature Applications Using Polymer Precursors

    Science.gov (United States)

    Cox, Sarah B.; Lui, Donovan; Gou, Jihua

    2014-01-01

    The development of high temperature structural composite materials has been very limited due to the high cost of the materials and the processing needed. Polymer Derived Ceramics (PDCs) begin as a polymer matrix, which allows a shape to be formed prior to the cure, and is then pyrolized in order to obtain a ceramic with the associated thermal and mechanical properties. The two PDCs used in this development are polysiloxane and polycarbosilane. Basalt fibers are used for the reinforcement in the composite system. The use of basalt in structural and high temperature applications has been under development for over 50 years, yet there has been little published research on the incorporation of basalt fibers as a reinforcement in composites. Continuous basalt fiber reinforced PDCs have been fabricated and tested for the applicability of this composite system as a high temperature structural composite material.

  11. A simple two-step method to fabricate highly transparent ITO/polymer nanocomposite films

    International Nuclear Information System (INIS)

    Liu, Haitao; Zeng, Xiaofei; Kong, Xiangrong; Bian, Shuguang; Chen, Jianfeng

    2012-01-01

    Highlights: ► A simple two-step method without further surface modification step was employed. ► ITO nanoparticles were easily to be uniformly dispersed in polymer matrix. ► ITO/polymer nanocomposite film had high transparency and UV/IR blocking properties. - Abstract: Transparent functional indium tin oxide (ITO)/polymer nanocomposite films were fabricated via a simple approach with two steps. Firstly, the functional monodisperse ITO nanoparticles were synthesized via a facile nonaqueous solvothermal method using bifunctional chemical agent (N-methyl-pyrrolidone, NMP) as the reaction solvent and surface modifier. Secondly, the ITO/acrylics polyurethane (PUA) nanocomposite films were fabricated by a simple sol-solution mixing method without any further surface modification step as often employed traditionally. Flower-like ITO nanoclusters with about 45 nm in diameter were mono-dispersed in ethyl acetate and each nanocluster was assembled by nearly spherical nanoparticles with primary size of 7–9 nm in diameter. The ITO nanoclusters exhibited an excellent dispersibility in polymer matrix of PUA, remaining their original size without any further agglomeration. When the loading content of ITO nanoclusters reached to 5 wt%, the transparent functional nanocomposite film featured a high transparency more than 85% in the visible light region (at 550 nm), meanwhile cutting off near-infrared radiation about 50% at 1500 nm and blocking UV ray about 45% at 350 nm. It could be potential for transparent functional coating materials applications.

  12. Nanostructured Block Polymer Membranes as High Capacity Adsorbers for the Capture of Metal Ions from Water

    Science.gov (United States)

    Boudouris, Bryan; Weidman, Jacob; Mulvenna, Ryan; Phillip, William

    The efficient removal of metal ions from aqueous streams is of significant import in applications ranging from industrial waste treatment to the purification of drinking water. An emerging paradigm associated with this separation is one that utilizes membrane adsorbers as a means by which to bind metal salt contaminants. Here, we demonstrate that the casting of an A-B-C triblock polymer using the self-assembly and non-solvent induced phase separation (SNIPS) methodology results in a nanoporous membrane geometry. The nature of the triblock polymer affords an extremely high density of binding sites within the membrane. As such, we demonstrate that the membranes with binding capacities equal to that of state-of-the-art packed bed columns. Moreover, because the affinity of the C moiety can be tuned, highly selective binding events can occur based solely on the chemistry of the block polymer and the metal ions in solution (i.e., in a manner that is independent of the size of the metal ions). Due to these combined facts, these membranes efficiently remove heavy metal (e.g., lead- and cadmium-based) salts from contaminated water streams with greater than 95% efficiency. Finally, we show that the membranes can be regenerated through a simple treatment in order to provide long-lasting adsorber systems as well. Thus, it is anticipated that these nanostructured triblock polymer membranes are a platform by which to obtain next-generation water purification processes.

  13. A Facile and General Approach to Recoverable High-Strain Multishape Shape Memory Polymers.

    Science.gov (United States)

    Li, Xingjian; Pan, Yi; Zheng, Zhaohui; Ding, Xiaobin

    2018-03-01

    Fabricating a single polymer network with no need to design complex structures to achieve an ideal combination of tunable high-strain multiple-shape memory effects and highly recoverable shape memory property is a great challenge for the real applications of advanced shape memory devices. Here, a facile and general approach to recoverable high-strain multishape shape memory polymers is presented via a random copolymerization of acrylate monomers and a chain-extended multiblock copolymer crosslinker. As-prepared shape memory networks show a large width at the half-peak height of the glass transition, far wider than current classical multishape shape memory polymers. A combination of tunable high-strain multishape memory effect and as high as 1000% recoverable strain in a single chemical-crosslinking network can be obtained. To the best of our knowledge, this is the first thermosetting material with a combination of highly recoverable strain and tunable high-strain multiple-shape memory effects. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. High mobility polymer gated organic field effect transistor using zinc ...

    Indian Academy of Sciences (India)

    Organic thin film transistors were fabricated using evaporated zinc phthalocyanine as the active layer. Parylene film ... At room temperature, these transistors exhibit p-type conductivity with field-effect ... Keywords. Organic semiconductor; field effect transistor; phthalocyanine; high mobility. ... The evaporation rate was kept at ...

  15. New frontiers in Combinatorial and High-Throughput Materials and Polymer Research: 3rd DPI workshop on automated synthesis and high-throughput experimentation in Polymer and Materials Research at the Eindhoven University of Technology

    NARCIS (Netherlands)

    Adams, N.; Schubert, U.S.

    2005-01-01

    The Third International Workshop on Combinatorial and High-Throughput Materials and Polymer Research, sponsored and organized by the Dutch Polymer Institute (DPI), took place at the Eindhoven University of Technol., The Netherlands, on May 26 - 27, 2004. The workshop's purpose is two-fold: its

  16. Conductive polymer/high-TC superconductor sandwich structures: An example of a molecular switch for controlling superconductivity

    International Nuclear Information System (INIS)

    McDevitt, J.T.; Haupt, S.G.; Lo, R.K.

    1994-01-01

    The preparation of a hybrid conducting polymer/high-temperature superconductor device consisting of a polypyrrole coated YBa 2 Cu 3 O 7-x microbridge is reported. Electrochemical techniques are exploited to alter the oxidation state of the polymer and, in doing so, it is found for the first time that superconductivity can be modulated in a controllable and reproducible fashion by a polymer layer. Whereas the neutral (insulating) polypyrrole only slightly influences the electrical properties of the underlying YBa 2 Cu 3 O 7- film, the oxidized (conductive) polymer depresses T c by up to 50K. In a similar fashion, the oxidation state of the polymer is found to modulate reversibly the magnitude of J c , the superconducting critical current. Thus, a new type of molecular switch for controlling superconductivity is demonstrated. Electrochemical, resistance vs. temperature, atomic force microscopy and scanning electron microscopy measurements are utilized to explore the polymer/superconductor interactions

  17. Novel Semiconducting Polymers for Highly Efficient Solar Energy Harvesting

    Science.gov (United States)

    2014-03-11

    we have developed an effective approach to enhance PCE and achieved an unprecedented high PCE value around 9.4%. S SS S X O O S SO OS S X S S X...Address: 128.135.225.61 Language: English (en-us,en;q=0.7,zh-cn;q=0.3) User Agent: Mozilla/5.0 (Windows NT 5.1; rv:27.0) Gecko/20100101 Firefox /27.0 Http

  18. Multifunctional Optical Sensors for Nanomanometry and Nanothermometry: High-Pressure and High-Temperature Upconversion Luminescence of Lanthanide-Doped Phosphates-LaPO4/YPO4:Yb3+-Tm3.

    Science.gov (United States)

    Runowski, Marcin; Shyichuk, Andrii; Tymiński, Artur; Grzyb, Tomasz; Lavín, Víctor; Lis, Stefan

    2018-05-23

    Upconversion luminescence of nano-sized Yb 3+ and Tm 3+ codoped rare earth phosphates, that is, LaPO 4 and YPO 4 , has been investigated under high-pressure (HP, up to ∼25 GPa) and high-temperature (293-773 K) conditions. The pressure-dependent luminescence properties of the nanocrystals, that is, energy red shift of the band centroids, changes of the band ratios, shortening of upconversion lifetimes, and so forth, make the studied nanomaterials suitable for optical pressure sensing in nanomanometry. Furthermore, thanks to the large energy difference (∼1800 cm -1 ), the thermalized states of Tm 3+ ions are spectrally well-separated, providing high-temperature resolution, required in optical nanothermometry. The temperature of the system containing such active nanomaterials can be determined on the basis of the thermally induced changes of the Tm 3+ band ratio ( 3 F 2,3 → 3 H 6 / 3 H 4 → 3 H 6 ), observed in the emission spectra. The advantage of such upconverting optical sensors is the use of near-infrared light, which is highly penetrable for many materials. The investigated nanomanometers/nanothermometers have been successfully applied, as a proof-of-concept of a novel bimodal optical gauge, for the determination of the temperature of the heated system (473 K), which was simultaneously compressed under HP (1.5 and 5 GPa).

  19. Investigation of polymer composite for high dose dosimetry

    International Nuclear Information System (INIS)

    Pereira, E.L.M.; Batista, A.S.M.; Ribeiro, F.A.S.; Santos, A.P.; Faria, L.O.; Oliveira, A.H.

    2017-01-01

    Introduction: This paper presents the efficacy evaluation of PVDF and nanocomposites of the PVDF films for high gamma dosimetry. Our scope in this first part of our studies is the selection of the most promising film for future dosimetry trials, where the proportionality of response of the selected material will be investigated over a large range of doses and dose rates. Methods: Was prepared nanocomposites made by mixing Poly(vinylidene fluoride) (PVDF), zirconium oxide (ZrO 2 ) and multi-walled carbon nanotubes (MWCNTs) aiming to find dosimetric properties for applications in high dose dosimetry. The samples were irradiated with a Co-60 source at constant dose rate (16.7 kGy/h), with doses ranging from 100 to 2750 kGy. The UV-Vis and FTIR spectrophotometry have been used to monitor the appearing of C=C conjugated bonds and radio-oxidation of carbon (C=O). Results: FTIR spectrometry has that the absorbance intensities at 1715 cm -1 and 1730 cm -1 can be used for high dosimetry purposes for gamma doses ranging from 400 to 2750 kGy. In this range, it is possible to observe a linear relationship between Abs & Dose. Fading of signal was evaluated for one month and reproducibility in 2000 kGy dose. Conclusion: FTIR spectroscopic data revealed two optical absorption bands at 1715 cm -1 and 1730 cm -1 whose intensities are unambiguously related to gamma delivered dose ranging from 400 kGy to 2750 kGy. (author)

  20. Investigation of polymer composite for high dose dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, E.L.M.; Batista, A.S.M., E-mail: adriananuclear@yahoo.com.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil); Ribeiro, F.A.S.; Santos, A.P.; Faria, L.O.; Oliveira, A.H. [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2017-07-01

    Introduction: This paper presents the efficacy evaluation of PVDF and nanocomposites of the PVDF films for high gamma dosimetry. Our scope in this first part of our studies is the selection of the most promising film for future dosimetry trials, where the proportionality of response of the selected material will be investigated over a large range of doses and dose rates. Methods: Was prepared nanocomposites made by mixing Poly(vinylidene fluoride) (PVDF), zirconium oxide (ZrO{sub 2}) and multi-walled carbon nanotubes (MWCNTs) aiming to find dosimetric properties for applications in high dose dosimetry. The samples were irradiated with a Co-60 source at constant dose rate (16.7 kGy/h), with doses ranging from 100 to 2750 kGy. The UV-Vis and FTIR spectrophotometry have been used to monitor the appearing of C=C conjugated bonds and radio-oxidation of carbon (C=O). Results: FTIR spectrometry has that the absorbance intensities at 1715 cm{sup -1} and 1730 cm{sup -1} can be used for high dosimetry purposes for gamma doses ranging from 400 to 2750 kGy. In this range, it is possible to observe a linear relationship between Abs & Dose. Fading of signal was evaluated for one month and reproducibility in 2000 kGy dose. Conclusion: FTIR spectroscopic data revealed two optical absorption bands at 1715 cm{sup -1} and 1730 cm{sup -1} whose intensities are unambiguously related to gamma delivered dose ranging from 400 kGy to 2750 kGy. (author)

  1. Near-Field Scanning Optical Microscope for the Study of Polymer-Nanotube Interactions

    National Research Council Canada - National Science Library

    Carroll, David

    2000-01-01

    ... optical properties in comparison to the intrinsic polymers Recent absorption and luminescence studies of carbon nanotube composites based on electro-optic polymer hosts such as MEH-PPV, have revealed...

  2. Polymer-free Drug-Coated Coronary Stents in Patients at High Bleeding Risk

    DEFF Research Database (Denmark)

    Urban, Philip; Meredith, Ian T; Abizaid, Alexandre

    2015-01-01

    BACKGROUND: Patients at high risk for bleeding who undergo percutaneous coronary intervention (PCI) often receive bare-metal stents followed by 1 month of dual antiplatelet therapy. We studied a polymer-free and carrier-free drug-coated stent that transfers umirolimus (also known as biolimus A9......), a highly lipophilic sirolimus analogue, into the vessel wall over a period of 1 month. METHODS: In a randomized, double-blind trial, we compared the drug-coated stent with a very similar bare-metal stent in patients with a high risk of bleeding who underwent PCI. All patients received 1 month of dual...... ratio, 0.50; 95% CI, 0.37 to 0.69; Pbleeding who underwent PCI, a polymer-free umirolimus-coated stent was superior to a bare-metal stent with respect to the primary safety and efficacy end points when used with a 1-month course of dual antiplatelet...

  3. Further Improvement and System Integration of High Temperature Polymer Electrolyte Membrane Fuel Cells

    DEFF Research Database (Denmark)

    Li, Qingfeng; Jensen, Jens Oluf

    The new development in the field of polymer electrolyte membrane fuel cell (PEMFC) is high temperature PEMFC for operation above 100°C, which has been successfully demonstrated through the previous EC Joule III and the 5th framework programme. New challenges are encountered, bottlenecks for the new...... technology have been identified, and new concepts and solutions have been provisionally identified. FURIM is directed at tackling these key issues by concentrating on the further materials development, compatible technologies, and system integration of the high temperature PEMFC. The strategic developments...... of the FURIM are in three steps: (1) further improvement of the high temperature polymer membranes and related materials; (2) development of technological units including fuel cell stack, hydrocarbon reformer and afterburner, that are compatible with the HT-PEMFC; and (3) integration of the HT-PEMFC stack...

  4. High renewable content sandwich structures based on flax-basalt hybrids and biobased epoxy polymers

    Science.gov (United States)

    Colomina, S.; Boronat, T.; Fenollar, O.; Sánchez-Nacher, L.; Balart, R.

    2014-05-01

    In the last years, a growing interest in the development of high environmental efficiency materials has been detected and this situation is more accentuated in the field of polymers and polymer composites. In this work, green composite sandwich structures with high renewable content have been developed with core cork materials. The base resin for composites was a biobased epoxy resin derived from epoxidized vegetable oils. Hybrid basalt-flax fabrics have been used as reinforcements for composites and the influence of the stacking sequence has been evaluated in order to optimize the appropriate laminate structure for the sandwich bases. Core cork materials with different thickness have been used to evaluate performance of sandwich structures thus leading to high renewable content composite sandwich structures. Results show that position of basalt fabrics plays a key role in flexural fracture of sandwich structures due to differences in stiffness between flax and basalt fibers.

  5. Highly processable method for the construction of miniature conducting polymer moisture sensors

    Science.gov (United States)

    McGovern, Scott T.; Spinks, Geoffrey M.; Wallace, Gordon G.

    2005-02-01

    A polymer blend incorporating polyaniline (PAn) was used as a sensing medium in the construction of a resistance based humidity sensor. Aniline monomer was polymerised to PAn emeraldine salt (ES) in the presence of poly (butyl acrylate-co-vinyl acetate) and the processable blend was developed by redissolving 1-2 w/w% of the resulting sensing polymer residue in dichloromethane (DCM). Some of this residue was washed in ammonia solution to de-dope the PAn to emeraldine base (EB) to act as a protective layer on the surface of the sensing polymer. This residue was then washed with distilled water until a neutral pH was realised with the waste water, dried and redissolved in DCM at 1-2 w/w% to create a processable blend barrier polymer solution. The final sensor design utilised 125μm polyester insulated platinum wire as conducting electrodes that were dip coated in the PAn ES blend solution and dried in a desiccator. A protective coating was then applied by dip coating in the EB blend solution. The sensors had an overall final thickness of less than 200μm and showed high sensitivity to humidity, low resistance, and good reversibility without hysteresis. The EB protective layer was shown to give more stable and predictable responses to the sensors when placed inside curing epoxies. Polymer based thin film humidity sensors have the advantage that the high processability of the material allows for simple fabrication of a range of geometries including smaller sensor designs. Such sensors may find uses in detecting water content in a number of areas including composite materials, electronic textiles, food/electronics packaging and corrosion detection.

  6. Silicon-Polymer Encapsulation of High-Level Calcine Waste for Transportation or Disposal

    International Nuclear Information System (INIS)

    Loomis, G.G.; Miller, C.M.; Giansiracusa, J.A.; Kimmel, R.; Prewett, S.V.

    2000-01-01

    This report presents the results of an experimental study investigating the potential uses for silicon-polymer encapsulation of High Level Calcine Waste currently stored within the Idaho Nuclear Technology and Engineering Center (INTEC) at the Idaho National Engineering and Environmental Laboratory (INEEL). The study investigated two different applications of silicon polymer encapsulation. One application uses silicon polymer to produce a waste form suitable for disposal at a High Level Radioactive Waste Disposal Facility directly, and the other application encapsulates the calcine material for transportation to an offsite melter for further processing. A simulated waste material from INTEC, called pilot scale calcine, which contained hazardous materials but no radioactive isotopes was used for the study, which was performed at the University of Akron under special arrangement with Orbit Technologies, the originators of the silicon polymer process called Polymer Encapsulation Technology (PET). This document first discusses the PET process, followed by a presentation of past studies involving PET applications to waste problems. Next, the results of an experimental study are presented on encapsulation of the INTEC calcine waste as it applies to transportation or disposal of calcine waste. Results relating to long-term disposal include: (1) a characterization of the pilot calcine waste; (2) Toxicity Characteristic Leaching Procedure (TCLP) testing of an optimum mixture of pilot calcine, polysiloxane and special additives; and, (3) Material Characterization Center testing MCC-1P evaluation of the optimum waste form. Results relating to transportation of the calcine material for a mixture of maximum waste loading include: compressive strength testing, 10-m drop test, melt testing, and a Department of Transportation (DOT) oxidizer test

  7. High yield silicon carbide pre-ceramic polymers

    International Nuclear Information System (INIS)

    Baney, R.H.

    1982-01-01

    Polysilanes which are substituted with (CH 3 ) 3 SiO-groups are useful for the preparation in high yields of fine grained silicon carbide ceramic materials. They consist of 0 to 60 mole % (CH 3 ) 2 Si units and 100 to 40 mole % CH 3 Si units, all Si valences not satisfied by CH 3 groups or Si atoms being directed to groups (CH 3 ) 3 SiO-, which siloxane groups amount to 23 to 61 weight % of the polysilane. They are prepared by reaction of the corresponding chloro- or bromo-methyl polysilanes with at least the stoichiometric amounts of (CH 3 ) 3 SiOSi(CH 3 ) 3 and water in the presence of a strong acid. (author)

  8. A high voltage DC-DC converter driving a Dielectric Electro Active Polymer actuator for wind turbine flaps

    DEFF Research Database (Denmark)

    Thummala, Prasanth; Zhang, Zhe; Andersen, Michael A. E.

    2012-01-01

    The Dielectric Electro Active Polymer (DEAP) material is a very thin (~80 μm) silicone elastomer film with a compliant metallic electrode layer on both sides. The DEAP is fundamentally a capacitor that is capable of very high strain. The property that the polymer changes its shape, as a result...

  9. A novel and high-effective redox-mediated gel polymer electrolyte for supercapacitor

    International Nuclear Information System (INIS)

    Ma, Guofu; Feng, Enke; Sun, Kanjun; Peng, Hui; Li, Jiajia; Lei, Ziqiang

    2014-01-01

    Graphical abstract: - Highlights: • Alkali and P-phenylenediamine doped polyvinyl alcohol gel electrolyte is prepared. • The PVA-KOH-PPD gel electrolyte can also be used as separator. • The introduction of PPD increases the ionic conductivity of electrolyte. • The supercapacitor exhibits flexible and high energy density. - Abstract: A supercapacitor utilize a novel redox-mediated gel polymer (PVA-KOH-PPD) as electrolyte and separator, and activated carbon as electrodes is assembled. The PVA-KOH-PPD gel polymer as potential electrolyte for supercapacitor is investigated by cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy techniques. It is found that the supercapacitor exhibits high ionic conductivity (25 mS cm −1 ), large electrode specific capacitance (611 F g −1 ) and high energy density (82.56 Wh kg −1 ). The high performance is attributed to the addition of quick redox reactions at the electrolyte|electrode interface as PPD undergoes a two-proton/two-electron reduction and oxidation during cycling. Furthermore, the supercapacitor with PVA-KOH-PPD gel polymer shows excellent charge-discharge stability, after 1000 charge-discharge cycles, the supercapacitor still retains a high electrode specific capacitance of 470 F g −1 . It is believed that the idea using redox mediator has a good prospect for improving the performances of supercapacitors

  10. Synthesis of polymer gel electrolyte with high molecular weight poly(methyl methacrylate)-clay nanocomposite

    International Nuclear Information System (INIS)

    Meneghetti, Paulo; Qutubuddin, Syed; Webber, Andrew

    2004-01-01

    Polymer nanocomposite gel electrolytes consisting of high molecular weight poly(methyl methacrylate) PMMA-clay nanocomposite, ethylene carbonate (EC)/propylene carbonate (PC) as plasticizer, and LiClO 4 electrolyte are reported. Montmorillonite clay was ion exchanged with a zwitterionic surfactant (octadecyl dimethyl betaine) and dispersed in methyl methacrylate, which was then polymerized to synthesize PMMA-clay nanocomposites. The nanocomposite was dissolved in a mixture of EC/PC with LiClO 4 , heated and pressed to obtain polymer gel electrolyte. X-ray diffraction (XRD) of the gels indicated intercalated clay structure with d-spacings of 2.85 and 1.40 nm. In the gel containing plasticizer, the clay galleries shrink suggesting intercalation rather than partial exfoliation observed in the PMMA-clay nanocomposite. Ionic conductivity varied slightly and exhibited a maximum value of 8 x 10 -4 S/cm at clay content of 1.5 wt.%. The activation energy was determined by modeling the conductivity with a Vogel-Tamman-Fulcher expression. The clay layers are primarily trapped inside the polymer matrix. Consequently, the polymer does not interact significantly with LiClO 4 electrolyte as shown by FTIR. The presence of the clay increased the glass transition temperature (Tg) of the gel as determined by differential scanning calorimetry. The PMMA nanocomposite gel electrolyte shows a stable lithium interfacial resistance over time, which is a key factor for use in electrochemical applications

  11. Full Polymer Dielectric Elastomeric Actuators (DEA Functionalised with Carbon Nanotubes and High-K Ceramics

    Directory of Open Access Journals (Sweden)

    Tilo Köckritz

    2016-09-01

    Full Text Available Dielectric elastomer actuators (DEA are special devices which have a simple working and construction principle and outstanding actuation properties. The DEAs consist of a combination of different materials for the dielectric and electrode layers. The combination of these layers causes incompatibilities in their interconnections. Dramatic differences in the mechanical properties and bad adhesion of the layers are the principal causes for the reduction of the actuation displacement and strong reduction of lifetime. Common DEAs achieve actuation displacements of 2% and a durability of some million cycles. The following investigations represent a new approach to solving the problems of common systems. The investigated DEA consists of only one basic raw polymer, which was modified according to the required demands of each layer. The basic raw polymer was modified with single-walled carbon nanotubes or high-k ceramics, for example, lead magnesium niobate-lead titanate. The development of the full polymer DEA comprised the development of materials and technologies to realise a reproducible layer composition. It was proven that the full polymer actuator worked according to the theoretical rules. The investigated system achieved actuation displacements above 20% regarding thickness, outstanding interconnections at each layer without any failures, and durability above 3 million cycles without any indication of an impending malfunction.

  12. A new three-dimensional bis(benzimidazole)-based cadmium(II) coordination polymer

    Science.gov (United States)

    Hao, Shao Yun; Hou, Suo Xia; Hao, Zeng Chuan; Cui, Guang Hua

    2018-01-01

    A new coordination polymer (CP), formulated as [Cd(L)(DCTP)]n (1) (L = 1,1‧-(1,4-butanediyl)bis(2-methylbenzimidazole), H2DCTP = 2,5-dichloroterephthalic acid), was synthesized under hydrothermal conditions and the performance as luminescent probe was also investigated. Single-crystal X-ray diffraction reveals CP 1 is a 3D 3-fold interpenetrated dia network with large well-defined pores. It is found that CP 1 revealed highly sensitive luminescence sensing for Fe3 + ions in acetonitrile solution with a high quenching efficiency of KSV = 2541.238 L·mol- 1 and a low detection limit of 3.2 μM (S/N = 3). Moreover, the photocatalytic efficiency of 1 for degradation of methylene blue could reach 82.8% after 135 min. Therefore, this coordination polymer could be viewed as multifunctional material for selectively sensing Fe3 + ions and effectively degrading dyes.

  13. Study of Polymeric Luminescent Blend (PC/PMMA) Doped with Europium Complex under Gamma-Iradiation

    International Nuclear Information System (INIS)

    Parra, D. F.

    2006-01-01

    Spectroscopic properties of blends formed by bisphenol-A polycarbonate (PC) and poly(methyl methacrylate) (PMMA) doped with europium in organic complex were studied. Polymeric luminescent blends are potential materials for many applications; however, little information has been reported concerning the stability under thermal and radiation conditions. Luminescent films were synthesized from europium thenoyltrifluoroacetonate at different concentrations doped in PC/PMMA blends. Films produced of the luminescent polymer blend were irradiated in a 60 C o source. Their luminescent properties, in the solid state, as well as, the thermal oxidative resistance after gamma irradiation was investigated. These systems were characterized by elemental analysis, thermogravimetry (TGA), differential scanning calorimetry (DSC) and infrared spectroscopy (FTIR). Based on TGA data, the thermal stability of PC/PMMA:(tta)3 system is higher than the polymer blend. The DSC results indicated that those new systems are chemically stables. The emission spectra of the Eu 3 +-tta complex doped in the PC/PMMA recorded at 298 and 77 K exhibited the characteristic bands arising from the 5 D 0 →7 F J transitions (J = 0-6). The luminescence intensity decreases with increasing of precursor concentration in the doped polymer obtained by chemical reaction. This result is different from that of samples obtained by physical method in melting doping. The blend was irradiated under ionizing radiation of 60 C o source. After irradiation of the luminescent films the physical properties of luminescence, thermal and oxidative stability were evaluated.(Fapesp and Cnpq financial support)

  14. Microwave-assisted synthesis of highly luminescent N- and S-co-doped carbon dots as a ratiometric fluorescent probe for levofloxacin.

    Science.gov (United States)

    Li, Huiyu; Xu, Yuan; Ding, Jie; Zhao, Li; Zhou, Tianyu; Ding, Hong; Chen, Yanhua; Ding, Lan

    2018-01-10

    Uniform N- and S-co-doped carbon dots (NSCDs) with fluorescence quantum yields of up to 64% were synthesized via a one-step microwave-assisted method. Ammonium citrate and L-cysteine act as precursors, and synthesis is completed in 2.5 min using a 750 W microwave oven to give a 62% yield. The NSCDs show bright blue fluorescence (with excitation/emission peaks at 353/426 nm) and have narrow size distribution. On exposure to levofloxacin (LEV), the emission maximum shifts to 499 nm. This effect was used to design ratiometric (2-wavelength) assays for LEV. The fluorometric method (based on measurement of the fluorescence intensity ratio at 499 and 426 nm) has a detection limit of 5.1 μg·L -1 (3σ/k) and a linear range that extends from 0.01 to 70 mg·L -1 . The method was applied to the determination of LEV in three kinds of spiked water samples and has recoveries in the range from 98.6 to 106.8%. The fluorescent probe described here is highly selective and sensitive. Graphical Abstract Highly luminescent N- and S-co-doped carbon dots were synthesized using AC (ammonium citrate) and Cys (L-cysteine) by microwave-assisted method, and were applied to the visual and ratiometric fluorescence determination of LEV (levofloxacin).

  15. Processing and Characterization of Basalt Fiber Reinforced Ceramic Composites for High Temperature Applications Using Polymer Precursors

    Science.gov (United States)

    Cox, Sarah B.; Lui, Donovan; Wang, Xin; Gou, Jihua

    2014-01-01

    The development of high temperature structural composite materials has been very limited due to the high cost of the materials and the processing needed. Ceramics can take much higher temperatures, but they are difficult to produce and form in bulk volumes. Polymer Derived Ceramics (PDCs) begin as a polymer matrix, allowing a shape to be formed and cured and then to be pyrolized in order to obtain a ceramic with the associated thermal and mechanical properties. The two PDCs used in this development are polysiloxane and polycarbosilane. Polysiloxanes contain a silicon oxycarbide backbone when pyrolized up to 1000 deg C. Polycarbosilane, an organosilicon polymer, contain a silicon-carbon backbone; around 1200 deg C, Beta-SiC begins to crystallize. The use of basalt in structural and high temperature applications has been under development for over 50 years, yet there has been little published research on the incorporation of basalt fibers as a reinforcement in composites. Basalt is a naturally occurring material found in volcanic rock. Continuous basalt fiber reinforced PDCs have been fabricated and tested for the applicability of this composite system as a high temperature structural composite material. Thermal and mechanical testing includes oxyacetylene torch testing and three point bend testing.

  16. Processing and Characterization of Basalt Fiber Reinforced Ceramic Composites for High Temperature Applications Using Polymer Precursors

    Science.gov (United States)

    Cox, Sarah B.; Lui, Donovan; Gou, Jihua

    2014-01-01

    The development of high temperature structural composite materials has been very limited due to the high cost of the materials and the processing needed. Ceramics can take much higher temperatures, but they are difficult to produce and form in bulk volumes. Polymer Derived Ceramics (PDCs) begin as a polymer matrix, allowing a shape to be formed and cured and then to be pyrolized in order to obtain a ceramic with the associated thermal and mechanical properties. The two PDCs used in this development are polysiloxane and polycarbosilane. Polysiloxanes contain a silicon oxycarbide backbone when pyrolized up to 1000C. Polycarbosilane, an organosilicon polymer, contain a silicon-carbon backbone; around 1200C, beta-SiC begins to crystallize. The use of basalt in structural and high temperature applications has been under development for over 50 years, yet there has been little published research on the incorporation of basalt fibers as a reinforcement in composites. Basalt is a naturally occurring material found in volcanic rock. Continuous basalt fiber reinforced PDCs have been fabricated and tested for the applicability of this composite system as a high temperature structural composite material. Thermal and mechanical testing includes oxyacetylene torch testing and three point bend testing.

  17. Laser generated ultrasound sources using polymer nanocomposites for high frequency metrology

    KAUST Repository

    Rajagopal, Srinath

    2017-11-22

    Accurate characterization of ultrasound fields generated by diagnostic and therapeutic transducers is critical for patient safety. This requires hydrophones calibrated to a traceable standard and currently the upper calibration frequency range available to the user community is limited to a frequency of 40 MHz. However, the increasing use of high frequencies for both imaging and therapy necessitates calibrations to frequencies well beyond this range. For this to be possible, a source of high amplitude, broadband, quasi-planar and stable ultrasound fields is required. This is difficult to achieve using conventional piezoelectric sources, but laser generated ultrasound is a promising technique in this regard. In this study, various polymer-carbon nanotube nanocomposites (PNC) were fabricated and tested for their suitability for such an application by varying the polymer type, carbon nanotubes weight content in the polymer, and PNC thickness. A broadband hydrophone was used to measure the peak pressure and bandwidth of the laser generated ultrasound pulse. Peak-positive pressures of up to 8 MPa and −6dB bandwidths of up to 40 MHz were recorded. There is a nonlinear dependence of the peak pressure on the laser fluence and the bandwidth scales inversely proportionally to the peak pressure. The high-pressure plane waves generated from this preliminary investigation has demonstrated that laser generated ultrasound sources are a promising technique for high frequency calibration of hydrophones.

  18. Luminescence imaging using radionuclides: a potential application in molecular imaging

    International Nuclear Information System (INIS)

    Park, Jeong Chan; Il An, Gwang; Park, Se-Il; Oh, Jungmin; Kim, Hong Joo; Su Ha, Yeong; Wang, Eun Kyung; Min Kim, Kyeong; Kim, Jung Young; Lee, Jaetae; Welch, Michael J.; Yoo, Jeongsoo

    2011-01-01

    Introduction: Nuclear and optical imaging are complementary in many aspects and there would be many advantages when optical imaging probes are prepared using radionuclides rather than classic fluorophores, and when nuclear and optical dual images are obtained using single imaging probe. Methods: The luminescence intensities of various radionuclides having different decay modes have been assayed using luminescence imaging and in vitro luminometer. Radioiodinated Herceptin was injected into a tumor-bearing mouse, and luminescence and microPET images were obtained. The plant dipped in [ 32 P]phosphate solution was scanned in luminescence mode. Radio-TLC plate was also imaged in the same imaging mode. Results: Radionuclides emitting high energy β + /β - particles showed higher luminescence signals. NIH3T6.7 tumors were detected in both optical and nuclear imaging. The uptake of [ 32 P]phosphate in plant was easily followed by luminescence imaging. Radio-TLC plate was visualized and radiochemical purity was quantified using luminescence imaging. Conclusion: Many radionuclides with high energetic β + or β - particles during decay were found to be imaged in luminescence mode due mainly to Cerenkov radiation. 'Cerenkov imaging' provides a new optical imaging platform and an invaluable bridge between optical and nuclear imaging. New optical imaging probes could be easily prepared using well-established radioiodination methods. Cerenkov imaging will have more applications in the research field of plant science and autoradiography.

  19. Highly efficient Cu(In,Ga)Se2 solar cells grown on flexible polymer films.

    Science.gov (United States)

    Chirilă, Adrian; Buecheler, Stephan; Pianezzi, Fabian; Bloesch, Patrick; Gretener, Christina; Uhl, Alexander R; Fella, Carolin; Kranz, Lukas; Perrenoud, Julian; Seyrling, Sieghard; Verma, Rajneesh; Nishiwaki, Shiro; Romanyuk, Yaroslav E; Bilger, Gerhard; Tiwari, Ayodhya N

    2011-09-18

    Solar cells based on polycrystalline Cu(In,Ga)Se(2) absorber layers have yielded the highest conversion efficiency among all thin-film technologies, and the use of flexible polymer films as substrates offers several advantages in lowering manufacturing costs. However, given that conversion efficiency is crucial for cost-competitiveness, it is necessary to develop devices on flexible substrates that perform as well as those obtained on rigid substrates. Such comparable performance has not previously been achieved, primarily because polymer films require much lower substrate temperatures during absorber deposition, generally resulting in much lower efficiencies. Here we identify a strong composition gradient in the absorber layer as the main reason for inferior performance and show that, by adjusting it appropriately, very high efficiencies can be obtained. This implies that future manufacturing of highly efficient flexible solar cells could lower the cost of solar electricity and thus become a significant branch of the photovoltaic industry.

  20. Micro-machinable polymer-derived ceramic sensors for high-temperature applications

    Science.gov (United States)

    Liu, Jian; Xu, Chengying; An, Linan

    2010-04-01

    Micro-sensors are highly desired for on-line temperature/pressure monitoring in turbine engines to improve their efficiency and reduce pollution. The biggest challenge for developing this type of sensors is that the sensors have to sustain at extreme environments in turbine engine environments, such as high-temperatures (>800 °C), fluctuated pressure and oxidation/corrosion surroundings. In this paper, we describe a class of sensors made of polymer-derived ceramics (PDCs) for such applications. PDCs have the following advantages over conventional ceramics, making them particularly suitable for these applications: (i) micromachining capability, (ii) tunable electric properties, and (iii) hightemperature capability. Here, we will discuss the materials and their properties in terms of their applications for hightemperature micro-sensors, and microfabrication technologies. In addition, we will also discuss the design of a heat-flux sensor based on polymer-derived ceramics.

  1. Life cycle assessment of Mexican polymer and high-durability cotton paper banknotes.

    Science.gov (United States)

    Luján-Ornelas, Cristina; Mancebo Del C Sternenfels, Uriel; Güereca, Leonor Patricia

    2018-02-23

    This study compares the environmental performance of Mexican banknotes printed on high-durability cotton paper (HD paper) and thermoplastic polymer (polymer) through a life cycle assessment to appraise the environmental impacts from the extraction of raw materials to the final disposal of the banknotes. The functional unit was defined considering the next parameters: 1) lifespan of the banknotes, stablished in 31.5 and 54months for HD paper and polymer, respectively; 2) denomination, selecting $200 pesos banknotes; 3) a 5year time frame and 4) a defined amount of money, in this case stablished as the monthly cash supply of an average Mexican household, equaling $12,708 pesos. Accordingly, 121 pieces for the HD paper and 71 pieces for the polymer banknotes were analyzed. The results favor the banknotes printed on polymer substrate primarily because of the longer lifespan of this type of material; however, there is a considerable environmental impact in the stages of distribution, followed by the extraction of the raw materials (crude oil) during manufacturing. Regarding the HD cotton paper, the major impact corresponds to extraction of the raw materials, followed by the distribution of the banknotes. The inclusion of the automatic teller machines (ATMs) in the life cycle assessment of banknotes shows that the electricity required by these devices became the largest contributor to the environmental impacts. Additionally, the sensitivity analysis that the average lifetime of the banknotes is a determining factor for the environmental impacts associated with the whole life cycle of this product. The life cycle stages that refer to the extraction of the raw materials, combined with the average lifetime of the banknotes and the electricity required during the usage stage, are determining factors in the total environmental impact associated with Mexican banknotes. Copyright © 2018 Elsevier B.V. All rights reserved.

  2. Highly red-shifted NIR emission from a novel anthracene conjugated polymer backbone containing Pt( ii ) porphyrins

    KAUST Repository

    Freeman, D. M. E.

    2015-11-30

    © The Royal Society of Chemistry 2016. We present the synthesis of a novel diphenylanthracene (DPA) based semiconducting polymer. The polymer is solubilised by alkoxy groups attached directly to a DPA monomer, meaning the choice of co-monomer is not limited to exclusively highly solubilising moieties. Interestingly, the polymer shows a red-shifted elecroluminescence maximum (510 nm) when compared to its photoluminescence maximum (450 nm) which we attribute to excimer formation. The novel polymer was utilised as a host for a covalently-linked platinum(ii) complexed porphyrin dopant. Emission from these polymers was observed in the NIR and again showed almost a 100 nm red shift from photoluminescence to electroluminescence. This work demonstrates that utilising highly aggregating host materials is an effective tool for inducing red-shifted emission in OLEDs.

  3. Application of radiation grafting techniques to prepare the high molecular weight water-soluble polymer

    International Nuclear Information System (INIS)

    Le Hai; Nguyen Quoc Hien; Nguyen Tan Man; Truong Thi Hanh; Le Huu Tu; Tran Thi Tam; Pham Thi Sam; Pham Anh Tuan; Le Dinh Lang

    2003-01-01

    The results of the study on the preparation of the high molecular weight water-soluble polymers by radiation grafting and their properties is presented as follows: 1/ by radiation grafting, the molecular weight of PVA was increased 20 times and PAM was increased only 3 times; 2/ the thermal and medium stability of poly(vinyl alcohol) grafted with acrylamide was obviously improved. (LH)

  4. High resolution neutron imaging of water in the polymer electrolyte fuel cell membrane

    Energy Technology Data Exchange (ETDEWEB)

    Mukherjee, Partha P [Los Alamos National Laboratory; Makundan, Rangachary [Los Alamos National Laboratory; Spendelow, Jacob S [Los Alamos National Laboratory; Borup, Rodney L [Los Alamos National Laboratory; Hussey, D S [NIST; Jacobson, D L [NIST; Arif, M [NIST

    2009-01-01

    Water transport in the ionomeric membrane, typically Nafion{reg_sign}, has profound influence on the performance of the polymer electrolyte fuel cell, in terms of internal resistance and overall water balance. In this work, high resolution neutron imaging of the Nafion{reg_sign} membrane is presented in order to measure water content and through-plane gradients in situ under disparate temperature and humidification conditions.

  5. The Mechanism of Burn-in Loss in a High Efficiency Polymer Solar Cell

    KAUST Repository

    Peters, Craig H.

    2011-10-11

    Degradation in a high efficiency polymer solar cell is caused by the formation of states in the bandgap. These states increase the energetic disorder in the system. The power conversion efficiency loss does not occur when current is run through the device in the dark but occurs when the active layer is photo-excited. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Thermally Activated Delayed Fluorescence in Polymers: A New Route toward Highly Efficient Solution Processable OLEDs.

    Science.gov (United States)

    Nikolaenko, Andrey E; Cass, Michael; Bourcet, Florence; Mohamad, David; Roberts, Matthew

    2015-11-25

    Efficient intermonomer thermally activated delayed fluorescence is demonstrated for the first time, opening a new route to achieving high-efficiency solution processable polymer light-emitting device materials. External quantum efficiency (EQE) of up to 10% is achieved in a simple fully solution-processed device structure, and routes for further EQE improvement identified. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. High temperature polymer film dielectrics for aerospace power conditioning capacitor applications

    Energy Technology Data Exchange (ETDEWEB)

    Venkat, Narayanan, E-mail: venkats3@gmail.co [University of Dayton Research Institute (UDRI), Dayton, OH 45469 (United States); Dang, Thuy D. [Air Force Research Laboratory-Nanostructured and Biological Materials Branch (AFRL/RXBN) (United States); Bai Zongwu; McNier, Victor K. [University of Dayton Research Institute (UDRI), Dayton, OH 45469 (United States); DeCerbo, Jennifer N. [Air Force Research Laboratory-Electrical Technology Branch (AFRL/RZPE), Wright-Patterson Air Force Base, OH 45433 (United States); Tsao, B.-H. [University of Dayton Research Institute (UDRI), Dayton, OH 45469 (United States); Stricker, Jeffery T. [Air Force Research Laboratory-Electrical Technology Branch (AFRL/RZPE), Wright-Patterson Air Force Base, OH 45433 (United States)

    2010-04-15

    Polymer dielectrics are the preferred materials of choice for capacitive energy-storage applications because of their potential for high dielectric breakdown strengths, low dissipation factors and good dielectric stability over a wide range of frequencies and temperatures, despite having inherently lower dielectric constants relative to ceramic dielectrics. They are also amenable to large area processing into films at a relatively lower cost. Air Force currently has a strong need for the development of compact capacitors which are thermally robust for operation in a variety of aerospace power conditioning applications. While such applications typically use polycarbonate (PC) dielectric films in wound capacitors for operation from -55 deg. C to 125 deg. C, future power electronic systems would require the use of polymer dielectrics that can reliably operate up to elevated temperatures in the range of 250-350 deg. C. The focus of this research is the generation and dielectric evaluation of metallized, thin free-standing films derived from high temperature polymer structures such as fluorinated polybenzoxazoles, post-functionalized fluorinated polyimides and fluorenyl polyesters incorporating diamond-like hydrocarbon units. The discussion is centered mainly on variable temperature dielectric measurements of film capacitance and dissipation factor and the effects of thermal cycling, up to a maximum temperature of 350 deg. C, on film dielectric performance. Initial studies clearly point to the dielectric stability of these films for high temperature power conditioning applications, as indicated by their relatively low temperature coefficient of capacitance (TCC) (approx2%) over the entire range of temperatures. Some of the films were also found to exhibit good dielectric breakdown strengths (up to 470 V/mum) and a film dissipation factor of the order of <0.003 (0.3%) at the frequency of interest (10 kHz) for the intended applications. The measured relative dielectric

  8. Theory of the high-frequency limiting viscosity of a dilute polymer solution. Pt. 2

    Energy Technology Data Exchange (ETDEWEB)

    Doi, M; Nakajima, H; Wada, Y

    1976-06-01

    High-frequency limiting viscosities of dilute polymer solutions are calculated on the basis of the author's previous theory for (1) necklace model of a chain with constant bond length and bond angle under a hindering rotational potential, and (2) broken rod model consisting of N rods with equal length connected by universal joints. Exact treatment is possible for a once-broken rod model, but the Monte Carlo method is used in the other calculations.

  9. Design, Synthesis, and Characterization of High Performance Polymer Electrolytes for Printed Electronics and Energy Storage

    Science.gov (United States)

    2016-03-31

    cross- linked , reversible ion gels exhibit among the highest ionic conductivities (>10 –2 S/cm) of known solvent-free, non-aqueous polymer...TFSA], the styrene domains were cross- linked by annealing at elevated temperature for ca. 20 min. The high ionic conductivity (ca. 10 mS/cm) of the...main innovations were the development of ion gels, materials that combine an ionic liquid with a gelating block copolymer to give mechanical strength

  10. Hydrogen bond based smart polymer for highly selective and tunable capture of multiply phosphorylated peptides.

    Science.gov (United States)

    Qing, Guangyan; Lu, Qi; Li, Xiuling; Liu, Jing; Ye, Mingliang; Liang, Xinmiao; Sun, Taolei

    2017-09-06

    Multisite phosphorylation is an important and common mechanism for finely regulating protein functions and subsequent cellular responses. However, this study is largely restricted by the difficulty to capture low-abundance multiply phosphorylated peptides (MPPs) from complex biosamples owing to the limitation of enrichment materials and their interactions with phosphates. Here we show that smart polymer can serve as an ideal platform to resolve this challenge. Driven by specific but tunable hydrogen bonding interactions, the smart polymer displays differential complexation with MPPs, singly phosphorylated and non-modified peptides. Importantly, MPP binding can be modulated conveniently and precisely by solution conditions, resulting in highly controllable MPP adsorption on material surface. This facilitates excellent performance in MPP enrichment and separation from model proteins and real biosamples. High enrichment selectivity and coverage, extraordinary adsorption capacities and recovery towards MPPs, as well as high discovery rates of unique phosphorylation sites, suggest its great potential in phosphoproteomics studies.Capture of low-abundance multiply phosphorylated peptides (MPPs) is difficult due to limitation of enrichment materials and their interactions with phosphates. Here the authors show, a smart polymer driven by specific but tunable hydrogen bonding interactions can differentially complex with MPPs, singly phosphorylated and non-modified peptides.

  11. Quantitative analysis of the gas evolved from high polymers in γ-irradiation

    International Nuclear Information System (INIS)

    Arakawa, Kazuo; Hayakawa, Naohiro; Kuriyama, Isamu

    1977-09-01

    Polymers are used as insulator of cables in nuclear-reactor radiation field. To estimate the evolution of gases when irradiated, total gas yield and composition were measured for variety of polymers. Samples were irradiated at room temperature in vacuo with 60 Co-γ rays. For ethylene propylene rubber (EPR), irradiation in high-temperature steam was also made. Composition of the gas was determined with a mass spectrometer. G-value of the total gaseous product was 3.2 to 3.4 for low-density polyethylene (LDPE) and 2.5 to 2.7 for high-density polyethylene (HDPE). In both polyethylene, hydrogen gas predominated. When an anti-radiation oil was added to LDPE, gas evolution was reduced drastically. For chloro-sulfonated PE (Hypalon), SO 2 gas was one of the major products even when the polymer contained only about 1% of sulfonyl groups. G-value of the total gas for EPR irradiated in high-temperature steam was 3.1, regardless of the temperature. (auth.)

  12. Morphology control in polymer blend fibers—a high throughput computing approach

    Science.gov (United States)

    Sesha Sarath Pokuri, Balaji; Ganapathysubramanian, Baskar

    2016-08-01

    Fibers made from polymer blends have conventionally enjoyed wide use, particularly in textiles. This wide applicability is primarily aided by the ease of manufacturing such fibers. More recently, the ability to tailor the internal morphology of polymer blend fibers by carefully designing processing conditions has enabled such fibers to be used in technologically relevant applications. Some examples include anisotropic insulating properties for heat and anisotropic wicking of moisture, coaxial morphologies for optical applications as well as fibers with high internal surface area for filtration and catalysis applications. However, identifying the appropriate processing conditions from the large space of possibilities using conventional trial-and-error approaches is a tedious and resource-intensive process. Here, we illustrate a high throughput computational approach to rapidly explore and characterize how processing conditions (specifically blend ratio and evaporation rates) affect the internal morphology of polymer blends during solvent based fabrication. We focus on a PS: PMMA system and identify two distinct classes of morphologies formed due to variations in the processing conditions. We subsequently map the processing conditions to the morphology class, thus constructing a ‘phase diagram’ that enables rapid identification of processing parameters for specific morphology class. We finally demonstrate the potential for time dependent processing conditions to get desired features of the morphology. This opens up the possibility of rational stage-wise design of processing pathways for tailored fiber morphology using high throughput computing.

  13. Dye-Incorporated Polynaphthalenediimide Acceptor for Additive-Free High-Performance All-Polymer Solar Cells.

    Science.gov (United States)

    Chen, Dong; Yao, Jia; Chen, Lie; Yin, Jingping; Lv, Ruizhi; Huang, Bin; Liu, Siqi; Zhang, Zhi-Guo; Yang, Chunhe; Chen, Yiwang; Li, Yongfang

    2018-04-16

    All-polymer solar cells (all-PSCs) can offer unique advantages for applications in flexible devices, and naphthalene diimide (NDI)-based polymer acceptors are the widely used polymer acceptors. However, their power conversion efficiency (PCE) still lags behind that of state-of-the-art polymer solar cells, due to low light absorption, suboptimal energy levels and the strong aggregation of the NDI-based polymer acceptor. Herein, a rhodanine-based dye molecule was introduced into the NDI-based polymer acceptor by simple random copolymerization and showed an improved light absorption coefficient, an up-shifted lowest unoccupied molecular orbital level and reduced crystallization. Consequently, additive-free all-PSCs demonstrated a high PCE of 8.13 %, which is one of the highest performance characteristics reported for all-PSCs to date. These results indicate that incorporating a dye into the n-type polymer gives insight into the precise design of high-performance polymer acceptors for all-PSCs. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Naphthacenodithiophene Based Polymers-New Members of the Acenodithiophene Family Exhibiting High Mobility and Power Conversion Efficiency

    KAUST Repository

    Knall, Astrid Caroline; Ashraf, Raja Shahid; Nikolka, Mark; Nielsen, Christian B.; Purushothaman, Balaji; Sadhanala, Aditya; Hurhangee, Michael; Broch, Katharina; Harkin, David J.; Nová k, Jiří ; Neophytou, Marios; Hayoz, Pascal; Sirringhaus, Henning; McCulloch, Iain

    2016-01-01

    Wide-bandgap conjugated polymers with a linear naphthacenodithiophene (NDT) donor unit are herein reported along with their performance in both transistor and solar cell devices. The monomer is synthesized starting from 2,6-dihydroxynaphthalene with a double Fries rearrangement as the key step. By copolymerization with 2,1,3-benzothiadiazole (BT) via a palladium-catalyzed Suzuki coupling reaction, NDT-BT co-polymers with high molecular weights and narrow polydispersities are afforded. These novel wide-bandgap polymers are evaluated as the semiconducting polymer in both organic field effect transistor and organic photovoltaic applications. The synthesized polymers reveal an optical bandgap in the range of 1.8 eV with an electron affinity of 3.6 eV which provides sufficient energy offset for electron transfer to PC70BM acceptors. In organic field effect transistors, the synthesized polymers demonstrate high hole mobilities of around 0.4 cm2 V–1 s–1. By using a blend of NDT-BT with PC70BM as absorber layer in organic bulk heterojunction solar cells, power conversion efficiencies of 7.5% are obtained. This value is among the highest obtained for polymers with a wider bandgap (larger than 1.7 eV), making this polymer also interesting for application in tandem or multijunction solar cells. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

  15. Naphthacenodithiophene Based Polymers-New Members of the Acenodithiophene Family Exhibiting High Mobility and Power Conversion Efficiency

    KAUST Repository

    Knall, Astrid Caroline

    2016-08-18

    Wide-bandgap conjugated polymers with a linear naphthacenodithiophene (NDT) donor unit are herein reported along with their performance in both transistor and solar cell devices. The monomer is synthesized starting from 2,6-dihydroxynaphthalene with a double Fries rearrangement as the key step. By copolymerization with 2,1,3-benzothiadiazole (BT) via a palladium-catalyzed Suzuki coupling reaction, NDT-BT co-polymers with high molecular weights and narrow polydispersities are afforded. These novel wide-bandgap polymers are evaluated as the semiconducting polymer in both organic field effect transistor and organic photovoltaic applications. The synthesized polymers reveal an optical bandgap in the range of 1.8 eV with an electron affinity of 3.6 eV which provides sufficient energy offset for electron transfer to PC70BM acceptors. In organic field effect transistors, the synthesized polymers demonstrate high hole mobilities of around 0.4 cm2 V–1 s–1. By using a blend of NDT-BT with PC70BM as absorber layer in organic bulk heterojunction solar cells, power conversion efficiencies of 7.5% are obtained. This value is among the highest obtained for polymers with a wider bandgap (larger than 1.7 eV), making this polymer also interesting for application in tandem or multijunction solar cells. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

  16. Effect of In-situ Cure on Measurement of Glass Transition Temperatures in High-temperature Thermosetting Polymers

    Science.gov (United States)

    2015-01-01

    TEMPERATURES IN HIGH-TEMPERATURE THERMOSETTING POLYMERS 5a. CONTRACT NUMBER In-House 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S...illustrated the difficulties inherent in measurement of the glass transition temperature of this high-temperature thermosetting polymer via dynamic...copyright protection in the United States. EFFECT OF IN-SITU CURE ON MEASUREMENT OF GLASS TRANSITION TEMPERATURES IN HIGH-TEMPERATURE THERMOSETTING

  17. Cleavage Luminescence from Cleaved Indium Phosphide

    International Nuclear Information System (INIS)

    Dong-Guang, Li

    2008-01-01

    We outline the experiments performed to gain further information about the structure and properties of cleaved InP surfaces. The experiments involved detecting the luminescence produced after cleaving thin InP plates within a high vacuum, by a process of converting the luminescence to an electrical signal which could be amplified and measured accurately. The experimental results show that the detected luminescence durations from cleaved InP are usually only about 10μs. It is believed that this time represents the time of travel of the crack with the actual recombination time being much shorter. Strong signals could also be picked up from cleaved InP in air

  18. High Kinetic Energy Penetrator Shielding and High Wear Resistance Materials Fabricated with Boron Nitride Nanotubes (BNNTS) and BNNT Polymer Composites

    Science.gov (United States)

    Kang, Jin Ho (Inventor); Sauti, Godfrey (Inventor); Smith, Michael W. (Inventor); Jordan, Kevin C. (Inventor); Park, Cheol (Inventor); Bryant, Robert George (Inventor); Lowther, Sharon E. (Inventor)

    2015-01-01

    Boron nitride nanotubes (BNNTs), boron nitride nanoparticles (BNNPs), carbon nanotubes (CNTs), graphites, or combinations, are incorporated into matrices of polymer, ceramic or metals. Fibers, yarns, and woven or nonwoven mats of BNNTs are used as toughening layers in penetration resistant materials to maximize energy absorption and/or high hardness layers to rebound or deform penetrators. They can be also used as reinforcing inclusions combining with other polymer matrices to create composite layers like typical reinforcing fibers such as Kevlar.RTM., Spectra.RTM., ceramics and metals. Enhanced wear resistance and usage time are achieved by adding boron nitride nanomaterials, increasing hardness and toughness. Such materials can be used in high temperature environments since the oxidation temperature of BNNTs exceeds 800.degree. C. in air. Boron nitride based composites are useful as strong structural materials for anti-micrometeorite layers for spacecraft and space suits, ultra strong tethers, protective gear, vehicles, helmets, shields and safety suits/helmets for industry.

  19. A novel conductive-polymer-based integration process for high-performance flip-chip packages

    Science.gov (United States)

    Lohokare, Saurabh

    Conductive polymers have recently attracted considerable attention for low-temperature fabrication of lead-free, reworkable, and flexible flip-chip interconnects. Using these materials, I demonstrate in this thesis a process that enables low-cost and high-resolution flip-chip interconnects using conventional micro-fabrication techniques. This fabrication process offers improved performance as compared to conventional flip-chip techniques, such as screen-printing, and allows for definition of interconnects with excellent surface uniformity and control over the bump profile. In order to demonstrate the utility and wide applicability of this process, several test implementations that serve as case studies were investigated. Specifically, novel InGaAsSb avalanche photodiodes (APDs), operating around lambda = 2m and targeted for free-space communication and biomedical spectroscopy applications, were fabricated and flip-chip-integrated to test the static electrical characteristics of the polymer bumps. Additionally, the dynamic electrical performance characteristics of the polymer bumps were studied by using AlGaAsSb/AlGaSb p-i-n photodetectors as a case study. The fabrication of these photodetectors, operating around lambda = 1.55mum and targeted for optical communication applications, was accomplished using a customized inductively coupled plasma (ICP) etch process that resulted in a low dark current and excellent speed (3dB bandwidth of 10GHz) and, responsivity (60% external quantum efficiency) characteristics. Furthermore, flip-chip integration was used to demonstrate a three-dimensional, point-to-point micro-optical interconnect, which was 2.33mm-long in a system 15.27mm3 in volume. Lastly, high-speed parallel optical interconnects were demonstrated using polymer-flip-chip-integrated 10GHz vertical-cavity surface-emitting laser (VCSEL) and DOEs. Such interconnects offer the ability to alleviate the communication bottleneck that is projected to occur in future, high

  20. Optical radiative properties of ablating polymers exposed to high-power arc plasmas

    Science.gov (United States)

    Becerra, Marley; Pettersson, Jonas

    2018-03-01

    The radiative properties of polymers exposed to high-intensity radiation are of importance for the numerical simulation of arc-induced ablation. The paper investigates the optical properties of polymethylmethacrylate PMMA and polyamide PA6 films exposed to high-power arc plasmas, which can cause ablation of the material. A four-flux radiative approximation is first used to estimate absorption and scattering coefficients of the tested materials in the ultraviolet (UV) and in the visible (VIS) ranges from spectrophotometric measurements. The temperature-induced variation of the collimated transmissivity of the polymers is also measured from room temperature to the glass temperature of PMMA and the melting temperature of PA6. Furthermore, band-averaged absorption and scattering coefficients of non-ablating and ablating polymers are estimated from the UV to the short-wavelength infrared (SWIR), covering the range of interest for the simulation of arc-induced ablation. These estimates are obtained from collimated transmissivities measured with an additional in situ photometric system that uses a high-power, transient arc plasma to both illuminate the samples and to induce ablation. It is shown that the increase in the bulk temperature of PA6 leads to a strong reversible increase in collimated transmissivity, significantly reducing the absorption and scattering coefficients of the material. A weaker but opposite effect of temperature on the optical properties is found in PMMA. As a consequence, it is suggested that the absorption coefficient of polymers used for arc-induced ablation estimates should not be taken directly from direct collimated transmissivity measurements at room temperature. The band-averaged radiation measurements also show that the layer of products released by ablation of PMMA produces scattering radiation losses mainly in the VIS-SWIR ranges, which are only a small fraction of the total incident arc radiation. In a similar manner, the ablation layer

  1. Solution-processable MoOx nanocrystals enable highly efficient reflective and semitransparent polymer solar cells

    KAUST Repository

    Jagadamma, Lethy Krishnan

    2016-09-09

    Solution-manufacturing of organic solar cells with best-in-class power conversion efficiency (PCE) will require all layers to be solution-coated without compromising solar cell performance. To date, the hole transporting layer (HTL) deposited on top of the organic bulk heterojunction layer in the inverted architecture is most commonly an ultrathin (<10 nm) metal oxide layer prepared by vacuum-deposition. Here, we show that an alcohol-based nanocrystalline MoOx suspension with carefully controlled nanocrystal (NC) size can yield state of the art reflective and semitransparent solar cells. Using NCs smaller than the target HTL thickness (∼10 nm) can yield compact, pinhole-free films which result in highly efficient polymer:fullerene bulk heterojunction (BHJ) solar cells with PCE=9.5%. The solution processed HTL is shown to achieve performance parity with vacuum-evaporated HTLs for several polymer:fullerene combinations and is even shown to work as hole injection layer in polymer light emitting diodes (PLED). We also demonstrate that larger MoOx NCs (30–50 nm) successfully composite MoOx with Ag nanowires (NW) to form a highly conducting, transparent top anode with exceptional contact properties. This yields state-of-the-art semitransparent polymer: fullerene solar cells with PCE of 6.5% and overall transmission >30%. The remarkable performance of reflective and semitransparent OPVs is due to the uncommonly high fill factors achieved using a carefully designed strategy for implementation of MoOx nanocrystals as HTL materials. © 2016 Elsevier Ltd

  2. Sub-ppb level detection of uranium using ligand sensitized luminescence

    International Nuclear Information System (INIS)

    Kumar, Satendra; Maji, S.; Joseph, M.; Sankaran, K.

    2015-01-01

    Uranyl ion (UO 2 2+ ) is known to exhibit weak luminescence in aqueous medium due to poor molar absorptivity and low quantum yield. In order to enhance the luminescence of uranyl ion in aqueous medium, luminescence enhancing reagents such as H 3 PO 4 , H 2 SO 4 , HClO 4 have been widely used. Like lanthanides, uranyl luminescence can also be sensitized by using some organic ligands. Pyridine 2,6-dicarboxylic acid (PDA) has shown enhancement of luminescence of uranyl in aqueous medium. Enhancement in intensity is due to sensitization of uranyl luminescence by PDA. In order to see the effect of non-aqueous medium, in this work, luminescence of uranyl-PDA complex has been studied in acetonitrile medium. More than one order luminescence enhancement has been observed compared to UO 2 2+ - PDA complex in aqueous medium. The lifetime of uranyl luminescence of the complex in acetonitrile medium is 90 μs which is very high compared to 10 μs in aqueous medium, suggesting that the luminescence enhancement is a result of reduction in non-radiative decay channels in acetonitrile medium. The large enhancement of uranyl luminescence of uranyl-PDA complex in acetonitrile medium can be used for ultra-trace level detection of uranium. Linearity in the luminescence intensity has been observed over the uranium concentration range of 5 to 80 ppb and the detection limit calculated using the criterion of 3 σ is ~ 0.2 ppb. (author)

  3. Lifetime of anode polymer in magnetically insulated ion diodes for high-intensity pulsed ion beam generation

    International Nuclear Information System (INIS)

    Zhu, X. P.; Dong, Z. H.; Han, X. G.; Xin, J. P.; Lei, M. K.

    2007-01-01

    Generation of high-intensity pulsed ion beam (HIPIB) has been studied experimentally using polyethylene as the anode polymer in magnetically insulated ion diodes (MIDs) with an external magnetic field. The HIPIB is extracted from the anode plasma produced during the surface discharging process on polyethylene under the electrical and magnetic fields in MIDs, i.e., high-voltage surface breakdown (flashover) with bombardments by electrons. The surface morphology and the microstructure of the anode polymer are characterized using scanning electron microscopy and differential scanning calorimetry, respectively. The surface roughening of the anode polymer results from the explosive release of trapped gases or newly formed gases under the high-voltage discharging, leaving fractured surfaces with bubble formation. The polyethylene in the surface layer degrades into low-molecular-weight polymers such as polyethylene wax and paraffin under the discharging process. Both the surface roughness and the fraction of low molecular polymers apparently increase as the discharging times are prolonged for multipulse HIPIB generation. The changes in the surface morphology and the composition of anode polymer lead to a noticeable decrease in the output of ion beam intensity, i.e., ion current density and diode voltage, accompanied with an increase in instability of the parameters with the prolonged discharge times. The diode voltage (or surface breakdown voltage of polymer) mainly depends on the surface morphology (or roughness) of anode polymers, and the ion current density on the composition of anode polymers, which account for the two stages of anode polymer degradation observed experimentally, i.e., stage I which has a steady decrease of the two parameters and stage II which shows a slow decrease, but with an enhanced fluctuation of the two parameters with increasing pulses of HIPIB generation

  4. Disintegration and field evaporation of thiolate polymers in high electric fields

    International Nuclear Information System (INIS)

    Nickerson, B.S.; Karahka, M.; Kreuzer, H.J.

    2015-01-01

    High electrostatic fields cause major changes in polymers, structural (e.g. electrostriction) and electronic (e.g. reduction of the “band gap” with final metallization). Using density functional theory we have studied field effects on amino-alkane-thiols and perfluoro-alkane-thiols adsorbed on a metal substrate. Our results agree well with the APT fragmentation spectra obtained by Stoffers, Oberdorfer and Schmitz and shed light on disintegration pathways. We demonstrate that in SAMs the HOMO/LUMO gap is again reduced as a function of the field strength and vanishes at evaporation. We also follow the field dependence of the dielectric constant and polarizability. - Highlights: • Simple model of thiolate polymers is used to understand trends leading to field evaporation. • Potential energy curves followed by dipole moment, electric polarizability and dielectric constant are examined. • Features including coil, tilt and electrostriction are featured alongside evaporated species and HOMO/LUMO gap.

  5. Disintegration and field evaporation of thiolate polymers in high electric fields

    Energy Technology Data Exchange (ETDEWEB)

    Nickerson, B.S., E-mail: brenden.nickerson@dal.ca; Karahka, M.; Kreuzer, H.J.

    2015-12-15

    High electrostatic fields cause major changes in polymers, structural (e.g. electrostriction) and electronic (e.g. reduction of the “band gap” with final metallization). Using density functional theory we have studied field effects on amino-alkane-thiols and perfluoro-alkane-thiols adsorbed on a metal substrate. Our results agree well with the APT fragmentation spectra obtained by Stoffers, Oberdorfer and Schmitz and shed light on disintegration pathways. We demonstrate that in SAMs the HOMO/LUMO gap is again reduced as a function of the field strength and vanishes at evaporation. We also follow the field dependence of the dielectric constant and polarizability. - Highlights: • Simple model of thiolate polymers is used to understand trends leading to field evaporation. • Potential energy curves followed by dipole moment, electric polarizability and dielectric constant are examined. • Features including coil, tilt and electrostriction are featured alongside evaporated species and HOMO/LUMO gap.

  6. Ultra-low power, highly uniform polymer memory by inserted multilayer graphene electrode

    International Nuclear Information System (INIS)

    Jang, Byung Chul; Kim, Jong Yun; Koo, Beom Jun; Yang, Sang Yoon; Choi, Sung-Yool; Seong, Hyejeong; Im, Sung Gap; Kim, Sung Kyu

    2015-01-01

    Filament type resistive random access memory (RRAM) based on polymer thin films is a promising device for next generation, flexible nonvolatile memory. However, the resistive switching nonuniformity and the high power consumption found in the general filament type RRAM devices present critical issues for practical memory applications. Here, we introduce a novel approach not only to reduce the power consumption but also to improve the resistive switching uniformity in RRAM devices based on poly(1,3,5-trimethyl-3,4,5-trivinyl cyclotrisiloxane) by inserting multilayer graphene (MLG) at the electrode/polymer interface. The resistive switching uniformity was thereby significantly improved, and the power consumption was markedly reduced by 250 times. Furthermore, the inserted MLG film enabled a transition of the resistive switching operation from unipolar resistive switching to bipolar resistive switching and induced self-compliance behavior. The findings of this study can pave the way toward a new area of application for graphene in electronic devices. (paper)

  7. Damping behavior of polymer composites with high volume fraction of NiMnGa powders

    Science.gov (United States)

    Sun, Xiaogang; Song, Jie; Jiang, Hong; Zhang, Xiaoning; Xie, Chaoying

    2011-03-01

    Polymer composites inserted with high volume fraction (up to 70 Vol%) of NiMnGa powders were fabricated and their damping behavior was investigated by dynamic mechanical analysis. It is found that the polymer matrix has little influence on the transformation temperatures of NiMnGa powders. A damping peak appears for NiMnGa/epoxy resin (EP) composites accompanying with the martensitic transformation or reverse martensitic transformation of NiMnGa powders during cooling or heating. The damping capacity for NiMnGa/EP composites increases linearly with the increase of volume fraction of NiMnGa powders and, decreases dramatically as the test frequency increases. The fracture strain of NiMnGa/EP composites decrease with the increase of NiMnGa powders.

  8. High-Temperature Polymer Composites Tested for Hypersonic Rocket Combustor Backup Structure

    Science.gov (United States)

    Sutter, James K.; Shin, E. Eugene; Thesken, John C.; Fink, Jeffrey E.

    2005-01-01

    Significant component weight reductions are required to achieve the aggressive thrust-toweight goals for the Rocket Based Combined Cycle (RBCC) third-generation, reusable liquid propellant rocket engine, which is one possible engine for a future single-stage-toorbit vehicle. A collaboration between the NASA Glenn Research Center and Boeing Rocketdyne was formed under the Higher Operating Temperature Propulsion Components (HOTPC) program and, currently, the Ultra-Efficient Engine Technology (UEET) Project to develop carbon-fiber-reinforced high-temperature polymer matrix composites (HTPMCs). This program focused primarily on the combustor backup structure to replace all metallic support components with a much lighter polymer-matrixcomposite- (PMC-) titanium honeycomb sandwich structure.

  9. Gas Separation Membranes Derived from High-Performance Immiscible Polymer Blends Compatibilized with Small Molecules.

    Science.gov (United States)

    Panapitiya, Nimanka P; Wijenayake, Sumudu N; Nguyen, Do D; Huang, Yu; Musselman, Inga H; Balkus, Kenneth J; Ferraris, John P

    2015-08-26

    An immiscible polymer blend comprised of high-performance copolyimide 6FDA-DAM:DABA(3:2) (6FDD) and polybenzimidazole (PBI) was compatibilized using 2-methylimidazole (2-MI), a commercially available small molecule. Membranes were fabricated from blends of 6FDD:PBI (50:50) with and without 2-MI for H2/CO2 separations. The membranes demonstrated a matrix-droplet type microstructure as evident with scanning electron microscopy (SEM) imaging where 6FDD is the dispersed phase and PBI is the continuous phase. In addition, membranes with 2-MI demonstrated a uniform microstructure as observed by smaller and more uniformly dispersed 6FDD domains in contrast to 6FDD:PBI (50:50) blend membranes without 2-MI. This compatibilization effect of 2-MI was attributed to interfacial localization of 2-MI that lowers the interfacial energy similar to a surfactant. Upon the incorporation of 2-MI, the H2/CO2 selectivity improved remarkably, compared to the pure blend, and surpassed the Robeson's upper bound. To our knowledge, this is the first report of the use of a small molecule to compatibilize a high-performance immiscible polymer blend. This approach could afford a novel class of membranes in which immiscible polymer blends can be compatibilized in an economical and convenient fashion.

  10. Nano silver diffusion behaviour on conductive polymer during doping process for high voltage application

    Science.gov (United States)

    Mohammad, A.; Mahmood, A.; Chin, K. T.; Danquah, M. K.; van Stratan, S.

    2017-06-01

    Conductive polymer had opened a new era of engineering for microelectronics and semiconductor applications. However, it is still a challenge for high voltage applications due to lower electrical conductivity compare to metals. This results tremendous energy losses during transmission and restricts its usage. In order to address such problem a novel method was investigated using nano silver particle doped iodothiophene since silver is the highest electrical conductive material. The experiments were carried out to study the organometallic diffusion behaviour of nanosilver doped iodothiophene with different concentration of iodothiophene. Five different mixing ratio between nanosilver and the solution of iodothiophene dissolved in diethyl ether were used which are 1:1.25, 1:1.5, 1:2.5, 1:3 and l:5. It was revealed that there is an effective threshold concentration of which the nano silver evenly distributed and there was no coagulation observed. These parameters laid the foundation of better doping process between the nano silver and the polymer significantly which would contribute developing conductive polymer towards high voltage application for industries that are vulnerable to corrosive environment.

  11. High-throughput measurement of polymer film thickness using optical dyes

    Science.gov (United States)

    Grunlan, Jaime C.; Mehrabi, Ali R.; Ly, Tien

    2005-01-01

    Optical dyes were added to polymer solutions in an effort to create a technique for high-throughput screening of dry polymer film thickness. Arrays of polystyrene films, cast from a toluene solution, containing methyl red or solvent green were used to demonstrate the feasibility of this technique. Measurements of the peak visible absorbance of each film were converted to thickness using the Beer-Lambert relationship. These absorbance-based thickness calculations agreed within 10% of thickness measured using a micrometer for polystyrene films that were 10-50 µm. At these thicknesses it is believed that the absorbance values are actually more accurate. At least for this solvent-based system, thickness was shown to be accurately measured in a high-throughput manner that could potentially be applied to other equivalent systems. Similar water-based films made with poly(sodium 4-styrenesulfonate) dyed with malachite green oxalate or congo red did not show the same level of agreement with the micrometer measurements. Extensive phase separation between polymer and dye resulted in inflated absorbance values and calculated thickness that was often more than 25% greater than that measured with the micrometer. Only at thicknesses below 15 µm could reasonable accuracy be achieved for the water-based films.

  12. Effect of high-dose irradiation on the optically stimulated luminescence of Al{sub 2}O{sub 3}:C

    Energy Technology Data Exchange (ETDEWEB)

    Yukihara, E.G. E-mail: yukihara@thor.phy.okstate.edu; Whitley, V.H.; McKeever, S.W.S. E-mail: swsm@okstate.edu; Akselrod, A.E.; Akselrod, M.S

    2004-06-01

    This paper examines the effect of high-dose irradiation on the optically stimulated luminescence (OSL) of Al{sub 2}O{sub 3}:C, principally on the shape of the OSL decay curve and on the OSL sensitivity. The effect of the degree of deep trap filling on the OSL was also studied by monitoring the sensitivity changes after doses of beta irradiation and after step-annealing of samples previously irradiated with high doses. The OSL response to dose shows a linear-supralinear-saturation behavior, with a decrease in the response for doses higher than those required for saturation. This behavior correlates with the sensitivity changes observed in the samples annealed only to 773 K, which show sensitization for doses up to 20-50 Gy and desensitization for higher doses. Data from the step-annealing study leads to the suggestion that the sensitization is caused by the filling of deep electron traps, which become thermally unstable at 1100-1200 K, whereas the desensitization is caused by the filling of deep hole traps, which become thermally unstable at 800-875 K, along with a concomitant decrease in the concentration of recombination centers (F{sup +}-centers). Changes in the shape of the OSL decay curves are also observed at high doses, the decay becoming faster as the dose increases. These changes in the OSL decay curves are discussed in terms of multiple overlapping components, each characterized by different photoionization cross-sections. However, using numerical solutions of the rate equations for a simple model consisting of a main trap and a recombination center, it is shown that the kinetics of OSL process may also be partially responsible for the changes in the OSL curves at high doses in Al{sub 2}O{sub 3}:C. Finally, the implication of these results for the dosimetry of heavy charged particles is discussed.

  13. Polymetallic lanthanide (III) complexes for the design of new luminescent materials

    International Nuclear Information System (INIS)

    Marchal, C.

    2008-09-01

    The incorporation of f elements in highly organized polymetallic complexes is of great interest in supramolecular chemistry and allows the combination of their nano-scopic size with the magnetic or optical properties of the metal ions. However due to the difficulty in controlling the coordination environment of these ions, the assembly of lanthanide-based polynuclear architectures has lagged behind that of other systems. These factors make the rational design for the construction of supramolecular lanthanide complexes quite challenging. In order to better understand the factors determining the assembly of lanthanide-based polymetallic arrays, we designed two different types of organic ligands, which favor, in one case, formation of infinite polymetallic complexes (coordination polymers), and in the case the assembly of discrete polymetallic architectures. Thus, we show that the use of flexible and multi-dentate picolinate-derivative ligands enables the formation of infinite and luminescent infinite frameworks which display very interesting luminescent properties. Geometry of the ligand has a great influence on the final network architecture. Particularly, implementation of four picolinate units within a tetrapodal ligand results in the controlled assembly of 1-D coordination polymers. Conversely to favor the controlled assembly of discrete polymetallic arrays we use dissymmetric ligands which displays low denticity. Complexation studies of a tridentate 8- hydroxyquinoline-derivative ligand as well as a tetradentate ligand possessing an oxazoline ring are presented. (author)

  14. Rare earth niobate coordination polymers

    Science.gov (United States)

    Muniz, Collin N.; Patel, Hiral; Fast, Dylan B.; Rohwer, Lauren E. S.; Reinheimer, Eric W.; Dolgos, Michelle; Graham, Matt W.; Nyman, May

    2018-03-01

    Rare-earth (RE) coordination polymers are infinitely tailorable to yield luminescent materials for various applications. Here we described the synthesis of a heterometallic rare-earth coordination compound ((CH3)2SO)3(RE)NbO(C2O4)3((CH3)2SO) = dimethylsulfoxide, DMSO, (C2O2= oxalate), (RE=La, Ce, Pr, Nd, Sm, Eu, Gd, Tb). The structure was obtained from single crystal X-ray diffraction of the La analogue. The Nb˭O and DMSO terminal-bonding character guides assembly of an open framework structure with noncentrosymmetric RE-coordination geometry, and large spacing between the RE centers. A second structure was observed by PXRD for the smaller rare earths (Dy, Ho, Er, Yb); this structure has not yet been determined. The materials were further characterized using FTIR, and photoluminescence measurements. Characteristic excitation and emission transitions were observed for RE = Nd, Sm, Eu, and Tb. Quantum yield (QY) measurements were performed by exciting Eu and Tb analoges at 394 nm (QY 66%) and 464 nm (QY 71%) for Eu; and 370 nm (QY=40%) for Tb. We attribute the high QY and bright luminescence to two main structure-function properties of the system; namely the absence of water in the structure, and absence of concentration quenching.

  15. Morphology-Dependent Trap Formation in High Performance Polymer Bulk Heterojunction Solar Cells

    KAUST Repository

    Beiley, Zach M.

    2011-06-28

    Bulk heterojunction solar cells (BHJs) based on poly[N-9″-hepta- decanyl-2,7-carbazole- alt -5,5-(4′,7′-di-2-thienyl-2′, 1′,3′-benzothiadiazole)] (PCDTBT) can have internal quantum efficiencies approaching 100% but require active layers that are too thin to absorb more than ∼70% of the above band gap light. When the active layer thickness is increased so that the cell absorbs more light, the fi ll factor and open circuit voltage decrease rapidly, so that the overall power conversion efficiency decreases. We fi nd that hole-traps in the polymer, which we characterize using space-charge limited current measurements, play an important role in the performance of PCDTBT-based BHJs and may limit the active layer thickness. Recombination due to carrier trapping is not often considered in BHJs because it is not believed to be a dominant loss mechanism in the "fruit-fl y" P3HT system. Furthermore, we show that in contrast to P3HT, PCDTBT has only weak short-range molecular order, and that annealing at temperatures above the glass transition decreases the order in the π-π stacking. The decrease in structural order is matched by the movement of hole-traps deeper into the band gap, so that thermal annealing worsens hole transport in the polymer and reduces the efficiency of PCDTBTbased BHJs. These fi ndings suggest that P3HT is not prototypical of the new class of high efficiency polymers, and that further improvement of BHJ efficiencies will necessitate the study of high efficiency polymers with low structural order. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. High-Pressure CO2 Sorption in Polymers of Intrinsic Microporosity under Ultrathin Film Confinement.

    Science.gov (United States)

    Ogieglo, Wojciech; Ghanem, Bader; Ma, Xiaohua; Wessling, Matthias; Pinnau, Ingo

    2018-04-04

    Ultrathin microporous polymer films are pertinent to the development and further spread of nanotechnology with very promising potential applications in molecular separations, sensors, catalysis, or batteries. Here, we report high-pressure CO 2 sorption in ultrathin films of several chemically different polymers of intrinsic microporosity (PIMs), including the prototypical PIM-1. Films with thicknesses down to 7 nm were studied using interference-enhanced in situ spectroscopic ellipsometry. It was found that all PIMs swell much more than non-microporous polystyrene and other high-performance glassy polymers reported previously. Furthermore, chemical modifications of the parent PIM-1 strongly affected the swelling magnitude. By investigating the behavior of relative refractive index, n rel , it was possible to study the interplay between micropores filling and matrix expansion. Remarkably, all studied PIMs showed a maximum in n rel at swelling of 2-2.5% indicating a threshold point above which the dissolution in the dense matrix started to dominate over sorption in the micropores. At pressures above 25 bar, all PIMs significantly plasticized in compressed CO 2 and for the ones with the highest affinity to the penetrant, a liquidlike mixing typical for rubbery polymers was observed. Reduction of film thickness below 100 nm revealed pronounced nanoconfinement effects and resulted in a large swelling enhancement and a quick loss of the ultrarigid character. On the basis of the partial molar volumes of the dissolved CO 2 , the effective reduction of the T g was estimated to be ∼200 °C going from 128 to 7 nm films.

  17. End-anchored polymers in good solvents from the single chain limit to high anchoring densities.

    Science.gov (United States)

    Whitmore, Mark D; Grest, Gary S; Douglas, Jack F; Kent, Michael S; Suo, Tongchuan

    2016-11-07

    An increasing number of applications utilize grafted polymer layers to alter the interfacial properties of solid substrates, motivating refinement in our theoretical understanding of such layers. To assess existing theoretical models of them, we have investigated end-anchored polymer layers over a wide range of grafting densities, σ, ranging from a single chain to high anchoring density limits, chain lengths ranging over two orders of magnitude, for very good and marginally good solvent conditions. We compare Monte Carlo and molecular dynamics simulations, numerical self-consistent field calculations, and experimental measurements of the average layer thickness, h, with renormalization group theory, the Alexander-de Gennes mushroom theory, and the classical brush theory. Our simulations clearly indicate that appreciable inter-chain interactions exist at all simulated areal anchoring densities so that there is no mushroom regime in which the layer thickness is independent of σ. Moreover, we find that there is no high coverage regime in which h follows the predicted scaling, h ∼ Nσ 1/3 , for classical polymer brushes either. Given that no completely adequate analytic theory seems to exist that spans wide ranges of N and σ, we applied scaling arguments for h as a function of a suitably defined reduced anchoring density, defined in terms of the solution radius of gyration of the polymer chains and N. We find that such a scaling approach enables a smooth, unified description of h in very good solvents over the full range of anchoring density and chain lengths, although this type of data reduction does not apply to marginal solvent quality conditions.

  18. Morphology-Dependent Trap Formation in High Performance Polymer Bulk Heterojunction Solar Cells

    KAUST Repository

    Beiley, Zach M.; Hoke, Eric T.; Noriega, Rodrigo; Dacuñ a, Javier; Burkhard, George F.; Bartelt, Jonathan A.; Salleo, Alberto; Toney, Michael F.; McGehee, Michael D.

    2011-01-01

    Bulk heterojunction solar cells (BHJs) based on poly[N-9″-hepta- decanyl-2,7-carbazole- alt -5,5-(4′,7′-di-2-thienyl-2′, 1′,3′-benzothiadiazole)] (PCDTBT) can have internal quantum efficiencies approaching 100% but require active layers that are too thin to absorb more than ∼70% of the above band gap light. When the active layer thickness is increased so that the cell absorbs more light, the fi ll factor and open circuit voltage decrease rapidly, so that the overall power conversion efficiency decreases. We fi nd that hole-traps in the polymer, which we characterize using space-charge limited current measurements, play an important role in the performance of PCDTBT-based BHJs and may limit the active layer thickness. Recombination due to carrier trapping is not often considered in BHJs because it is not believed to be a dominant loss mechanism in the "fruit-fl y" P3HT system. Furthermore, we show that in contrast to P3HT, PCDTBT has only weak short-range molecular order, and that annealing at temperatures above the glass transition decreases the order in the π-π stacking. The decrease in structural order is matched by the movement of hole-traps deeper into the band gap, so that thermal annealing worsens hole transport in the polymer and reduces the efficiency of PCDTBTbased BHJs. These fi ndings suggest that P3HT is not prototypical of the new class of high efficiency polymers, and that further improvement of BHJ efficiencies will necessitate the study of high efficiency polymers with low structural order. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. High-Pressure CO2 Sorption in Polymers of Intrinsic Microporosity under Ultrathin Film Confinement

    KAUST Repository

    Ogieglo, Wojciech

    2018-03-12

    Ultrathin microporous polymer films are pertinent to the development and further spread of nanotechnology with very promising potential applications in molecular separations, sensors, catalysis, or batteries. Here, we report high-pressure CO2 sorption in ultrathin films of several chemically different polymers of intrinsic microporosity (PIMs), including the prototypical PIM-1. Films with thicknesses down to 7 nm were studied using interference-enhanced in situ spectroscopic ellipsometry. It was found that all PIMs swell much more than non-microporous polystyrene and other high-performance glassy polymers reported previously. Furthermore, chemical modifications of the parent PIM-1 strongly affected the swelling magnitude. By investigating the behavior of relative refractive index, nrel, it was possible to study the interplay between micropores filling and matrix expansion. Remarkably, all studied PIMs showed a maximum in nrel at swelling of 2-2.5% indicating a threshold point above which the dissolution in the dense matrix started to dominate over sorption in the micropores. At pressures above 25 bar, all PIMs significantly plasticized in compressed CO2 and for the ones with the highest affinity to the penetrant, a liquidlike mixing typical for rubbery polymers was observed. Reduction of film thickness below 100 nm revealed pronounced nanoconfinement effects and resulted in a large swelling enhancement and a quick loss of the ultrarigid character. On the basis of the partial molar volumes of the dissolved CO2, the effective reduction of the Tg was estimated to be ∼200 °C going from 128 to 7 nm films.

  20. High-Pressure CO2 Sorption in Polymers of Intrinsic Microporosity under Ultrathin Film Confinement

    KAUST Repository

    Ogieglo, Wojciech; Ghanem, Bader; Ma, Xiaohua; Wessling, Matthias; Pinnau, Ingo

    2018-01-01

    Ultrathin microporous polymer films are pertinent to the development and further spread of nanotechnology with very promising potential applications in molecular separations, sensors, catalysis, or batteries. Here, we report high-pressure CO2 sorption in ultrathin films of several chemically different polymers of intrinsic microporosity (PIMs), including the prototypical PIM-1. Films with thicknesses down to 7 nm were studied using interference-enhanced in situ spectroscopic ellipsometry. It was found that all PIMs swell much more than non-microporous polystyrene and other high-performance glassy polymers reported previously. Furthermore, chemical modifications of the parent PIM-1 strongly affected the swelling magnitude. By investigating the behavior of relative refractive index, nrel, it was possible to study the interplay between micropores filling and matrix expansion. Remarkably, all studied PIMs showed a maximum in nrel at swelling of 2-2.5% indicating a threshold point above which the dissolution in the dense matrix started to dominate over sorption in the micropores. At pressures above 25 bar, all PIMs significantly plasticized in compressed CO2 and for the ones with the highest affinity to the penetrant, a liquidlike mixing typical for rubbery polymers was observed. Reduction of film thickness below 100 nm revealed pronounced nanoconfinement effects and resulted in a large swelling enhancement and a quick loss of the ultrarigid character. On the basis of the partial molar volumes of the dissolved CO2, the effective reduction of the Tg was estimated to be ∼200 °C going from 128 to 7 nm films.

  1. Luminescence study of spodumene

    International Nuclear Information System (INIS)

    Isotani, S.; Fujii, A.T.; Antonini, R.; Pontuschka, W.M.; Rabani, S.R.; Furtado, W.W.

    1990-02-01

    A comparative study is made of the luminescence of five kinds of spodumene from Minas Gerais, Brazil, studied previously by optical absorption spectroscopy. Natural gemstones are used which, in the course of the experiments, were irradiated with X-rays. (L.C.) [pt

  2. Silicon: electrochemistry and luminescence

    NARCIS (Netherlands)

    Kooij, Ernst Stefan

    1997-01-01

    The electrochemistry of crystalline and porous silicon and the luminescence from porous silicon has been studied. One chapter deals with a model for the anodic dissolution of silicon in HF solution. In following chapters both the electrochemistry and various ways of generating visible

  3. Polarization memory of white luminescence of Ag nanoclusters dispersed in glass host.

    Science.gov (United States)

    Kuznetsov, A S; Tikhomirov, V K; Moshchalkov, V V

    2012-09-10

    A mechanism for white luminescence of Ag nanoclusters dispersed in oxyfluoride glass host has been revealed by studying a temperature dependence of its polarization memory. The spectral dependence of the polarization memory indicates the presence of a variety of Ag nanoclusters, particularly emitting in the blue, green and red. Temperature activated intercluster energy transfer has been found responsible for white luminescence. The means for increasing luminescence quantum yield have been suggested. This efficient white luminescence may be used in highly demanded devices, such as luminescent lamps, displays, color phosphors for LEDs, photovoltaic devices based on down shifting of solar spectrum.

  4. Polymer concrete composites for the production of high strength pipe and linings in high temperature corrosive environments

    Science.gov (United States)

    Zeldin, A.; Carciello, N.; Fontana, J.; Kukacka, L.

    High temperature corrosive resistant, non-aqueous polymer concrete composites are described. They comprise about 12 to 20% by weight of a water-insoluble polymer binder polymerized in situ from a liquid monomer mixture consisting essentially of about 40 to 70% by weight of styrene, about 25 to 45% by weight acrylonitrile and about 2.5 to 7.5% by weight acrylamide or methacrylamide and about 1 to 10% by weight of a crosslinking agent. This agent is selected from the group consisting of trimethylolpropane trimethacrylate and divinyl benzene; and about 80 to 88% by weight of an inert inorganic filler system containing silica sand and portland cement, and optionally Fe/sub 2/O/sub 3/ or carbon black or mica. A free radical initiator such as di-tert-butyl peroxide, azobisisobutyronitrile, benzoyl peroxide, lauryl peroxide, other organic peroxides and combinations thereof to initiate crosspolymerization of the monomer mixture in the presence of said inorganic filler.

  5. Highly stable and low loss electro-optic polymer waveguides for high speed microring modulators using photodefinition

    Science.gov (United States)

    Balakrishnan, M.; Diemeer, M. B. J.; Driessen, A.; Faccini, M.; Verboom, W.; Reinhoudt, D. N.; Leinse, A.

    2006-02-01

    Different electro-optic polymer systems are analyzed with respect to their electro-optic activity, glass transition temperature (T g) and photodefinable properties. The polymers tested are polysulfone (PS) and SU8. The electro-optic chromophore, tricyanovinylidenediphenylaminobenzene (TCVDPA), which was reported to have a high photochemical stability 1 has been employed in the current work. Tert-butyl-TCVDPA, having bulky side groups, was synthesized and a doubling of the electro-optic coefficient (r33) compared to the unmodified TCVDPA was shown. A microring resonator design was made based on the PS-TCVDPA system. SU8 (passive) and TCVDPA (active) channel waveguides were fabricated by the photodefinition technique and the passive waveguide losses were measured to be 5 dB/cm at 1550 nm.

  6. Core-satellite Ag@BaTiO3 nanoassemblies for fabrication of polymer nanocomposites with high discharged energy density, high breakdown strength and low dielectric loss.

    Science.gov (United States)

    Xie, Liyuan; Huang, Xingyi; Li, Bao-Wen; Zhi, Chunyi; Tanaka, Toshikatsu; Jiang, Pingkai

    2013-10-28

    Dielectric polymer nanocomposites with high dielectric constant have wide applications in high energy density electronic devices. The introduction of high dielectric constant ceramic nanoparticles into a polymer represents an important route to fabricate nanocomposites with high dielectric constant. However, the nanocomposites prepared by this method generally suffer from relatively low breakdown strength and high dielectric loss, which limit the further increase of energy density and energy efficiency of the nanocomposites. In this contribution, by using core-satellite structured ultra-small silver (Ag) decorated barium titanate (BT) nanoassemblies, we successfully fabricated high dielectric constant polymer nanocomposites with enhanced breakdown strength and lower dielectric loss in comparison with conventional polymer-ceramic particulate nanocomposites. The discharged energy density and energy efficiency are derived from the dielectric displacement-electric field loops of the polymer nanocomposites. It is found that, by using the core-satellite structured Ag@BT nanoassemblies as fillers, the polymer nanocomposites can not only have higher discharged energy density but also have high energy efficiency. The mechanism behind the improved electrical properties was attributed to the Coulomb blockade effect and the quantum confinement effect of the introduced ultra-small Ag nanoparticles. This study could serve as an inspiration to enhance the energy storage densities of dielectric polymer nanocomposites.

  7. High aspect ratio micro tool manufacturing for polymer replication using mu EDM of silicon, selective etching and electroforming

    DEFF Research Database (Denmark)

    Tosello, Guido; Bissacco, Giuliano; Tang, Peter Torben

    2008-01-01

    Mass fabrication of polymer micro components with high aspect ratio micro-structures requires high performance micro tools allowing the use of low cost replication processes such as micro injection moulding. In this regard an innovative process chain, based on a combination of micro electrical di...... discharge machining (mu EDM) of a silicon substrate, electroforming and selective etching was used for the manufacturing of a micro tool. The micro tool was employed for polymer replication by means of the injection moulding process....

  8. Effect of In-Situ Cure on Measurement of Glass Transition Temperatures in High-Temperature Thermosetting Polymers (Briefing Charts)

    Science.gov (United States)

    2015-05-20

    TEMPERATURES IN HIGH-TEMPERATURE THERMOSETTING POLYMERS 5a. CONTRACT NUMBER In-House 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d...temperature thermosetting polymer via dynamic mechanical analysis alone. These difficulties result from the residual cure of samples heated beyond their...98) Prescribed by ANSI Std. 239.18 Effect of In-Situ Cure on Measurement of Glass Transition Temperatures in High-Temperature Thermosetting

  9. High temperature polymer electrolyte membrane fuel cells: Approaches, status, and perspectives

    DEFF Research Database (Denmark)

    This book is a comprehensive review of high-temperature polymer electrolyte membrane fuel cells (PEMFCs). PEMFCs are the preferred fuel cells for a variety of applications such as automobiles, cogeneration of heat and power units, emergency power and portable electronics. The first 5 chapters...... of and motivated extensive research activity in the field. The last 11 chapters summarize the state-of-the-art of technological development of high temperature-PEMFCs based on acid doped PBI membranes including catalysts, electrodes, MEAs, bipolar plates, modelling, stacking, diagnostics and applications....

  10. On γ-relaxation process in crystallizable polymers

    International Nuclear Information System (INIS)

    Mindiyarov, Kh.G.; Zelenev, Yu.V.; Bartenev, G.M.

    1975-01-01

    In the present paper, with the aid of radiothermoluminescence technique γ-relaxation processes are investigated, which are conditioned by molecular mobility and are associated with defects in the crystalline structure of polymers PEh, PP, and elastomers PIB, NK, SKD, SKI exposed to γ-rays of Co 60 at a dose rate of 1 Mrad. The shape of the thermoluminescence curve, i.e. the luminescence intensity in the α - γ-maxima, their relationship, position with respect to temperature are strongly dependent on the degree of crystallinity, on the thermal and mechanical prehistory. In highly crystalline samples of PEh and PP α-maximum may be absent. Dependence has been studied of the luminescence intensity in the α- and γ-maxima (Isub(α)/Isub(γ)) on the crystallization temperature; the curve passes through the minimum when the crystallization rate is maximum. The relationship Isub(γ)re of crystallinity degree

  11. High-Speed 3D Printing of High-Performance Thermosetting Polymers via Two-Stage Curing.

    Science.gov (United States)

    Kuang, Xiao; Zhao, Zeang; Chen, Kaijuan; Fang, Daining; Kang, Guozheng; Qi, Hang Jerry

    2018-04-01

    Design and direct fabrication of high-performance thermosets and composites via 3D printing are highly desirable in engineering applications. Most 3D printed thermosetting polymers to date suffer from poor mechanical properties and low printing speed. Here, a novel ink for high-speed 3D printing of high-performance epoxy thermosets via a two-stage curing approach is presented. The ink containing photocurable resin and thermally curable epoxy resin is used for the digital light processing (DLP) 3D printing. After printing, the part is thermally cured at elevated temperature to yield an interpenetrating polymer network epoxy composite, whose mechanical properties are comparable to engineering epoxy. The printing speed is accelerated by the continuous liquid interface production assisted DLP 3D printing method, achieving a printing speed as high as 216 mm h -1 . It is also demonstrated that 3D printing structural electronics can be achieved by combining the 3D printed epoxy composites with infilled silver ink in the hollow channels. The new 3D printing method via two-stage curing combines the attributes of outstanding printing speed, high resolution, low volume shrinkage, and excellent mechanical properties, and provides a new avenue to fabricate 3D thermosetting composites with excellent mechanical properties and high efficiency toward high-performance and functional applications. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Direct Creation of Highly Conductive Laser-Induced Graphene Nanocomposites from Polymer Blends.

    Science.gov (United States)

    Yazdi, Alireza Zehtab; Navas, Ivonne Otero; Abouelmagd, Ahmed; Sundararaj, Uttandaraman

    2017-09-01

    The current state-of-the-art mixing strategies of nanoparticles with insulating polymeric components have only partially utilized the unique electrical conductivity of graphene in nanocomposite systems. Herein, this paper reports a nonmixing method of direct creation of polymer/graphene nanocomposites from polymer blends via laser irradiation. Polycarbonate-laser-induced graphene (PC-LIG) nanocomposite is produced from a PC/polyetherimide (PC/PEI) blend after exposure to commercially available laser scribing with a power of ≈6 W and a speed of ≈2 cm s -1 . Extremely high electrical conductivities are obtained for the PC-LIG nanocomposites, ranging from 26 to 400 S m -1 , depending on the vol% of the starting PEI phase in the blend. To the authors' knowledge, these conductivity values are at least one order of magnitude higher than the values that are previously reported for conductive polymer/graphene nanocomposites prepared via mixing strategies. The comprehensive microscopy and spectroscopy characterizations reveal a complete graphitization of the PEI phase with columnar microstructure embedded in the PC phase. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Polymer dots grafted TiO2 nanohybrids as high performance visible light photocatalysts.

    Science.gov (United States)

    Li, Gen; Wang, Feng; Liu, Peng; Chen, Zheming; Lei, Ping; Xu, Zhongshan; Li, Zengxi; Ding, Yanfen; Zhang, Shimin; Yang, Mingshu

    2018-04-01

    As a new member of carbon dots (CDs), Polymer dots (PDs) prepared by hydrothermal treatment of polymers, usually consist of the carbon core and the connected partially degraded polymer chains. This type of CDs might possess aqueous solubility, non-toxicity, excellent stability against photo-bleaching and high visible light activity. In this research, PDs were prepared by a moderate hydrothermal treatment of polyvinyl alcohol, and PDs grafted TiO 2 (PDs-TiO 2 ) nanohybrids with TiOC bonds were prepared by a facile in-situ hydrothermal treatment of PDs and Ti (SO 4 ) 2 . Under visible light irradiation, the PDs-TiO 2 demonstrate excellent photocatalytic activity for methyl orange degradation, and the photocatalytic rate constant of PDs-TiO 2 is 3.6 and 9.5 times higher than that of pure TiO 2 and commercial P25, respectively. In addition, the PDs-TiO 2 exhibit good recycle stability under UV-Vis light irradiation. The interfacial TiOC bonds and the π-conjugated structures in PDs-TiO 2 can act as the pathways to quickly transfer the excited electrons between PDs and TiO 2 , therefore contribute to the excellent photocatalytic activity. Copyright © 2018 Elsevier Ltd. All rights reserved.

  14. Polymer Surface Engineering for Efficient Printing of Highly Conductive Metal Nanoparticle Inks.

    Science.gov (United States)

    Agina, Elena V; Sizov, Alexey S; Yablokov, Mikhail Yu; Borshchev, Oleg V; Bessonov, Alexander A; Kirikova, Marina N; Bailey, Marc J A; Ponomarenko, Sergei A

    2015-06-10

    An approach to polymer surface modification using self-assembled layers (SALs) of functional alkoxysilanes has been developed in order to improve the printability of silver nanoparticle inks and enhance adhesion between the metal conducting layer and the flexible polymer substrate. The SALs have been fully characterized by AFM, XPS, and WCA, and the resulting printability, adhesion, and electrical conductivity of the screen-printed metal contacts have been estimated by cross-cut tape test and 4-point probe measurements. It was shown that (3-mercaptopropyl)trimethoxysilane SALs enable significant adhesion improvements for both aqueous- and organic-based silver inks, approaching nearly 100% for PEN and PDMS substrates while exhibiting relatively low sheet resistance up to 0.1 Ω/sq. It was demonstrated that SALs containing functional -SH or -NH2 end groups offer the opportunity to increase the affinity of the polymer substrates to silver inks and thus to achieve efficient patterning of highly conductive structures on flexible and stretchable substrates.

  15. Star Polymers.

    Science.gov (United States)

    Ren, Jing M; McKenzie, Thomas G; Fu, Qiang; Wong, Edgar H H; Xu, Jiangtao; An, Zesheng; Shanmugam, Sivaprakash; Davis, Thomas P; Boyer, Cyrille; Qiao, Greg G

    2016-06-22

    Recent advances in controlled/living polymerization techniques and highly efficient coupling chemistries have enabled the facile synthesis of complex polymer architectures with controlled dimensions and functionality. As an example, star polymers consist of many linear polymers fused at a central point with a large number of chain end functionalities. Owing to this exclusive structure, star polymers exhibit some remarkable characteristics and properties unattainable by simple linear polymers. Hence, they constitute a unique class of technologically important nanomaterials that have been utilized or are currently under audition for many applications in life sciences and nanotechnologies. This article first provides a comprehensive summary of synthetic strategies towards star polymers, then reviews the latest developments in the synthesis and characterization methods of star macromolecules, and lastly outlines emerging applications and current commercial use of star-shaped polymers. The aim of this work is to promote star polymer research, generate new avenues of scientific investigation, and provide contemporary perspectives on chemical innovation that may expedite the commercialization of new star nanomaterials. We envision in the not-too-distant future star polymers will play an increasingly important role in materials science and nanotechnology in both academic and industrial settings.

  16. Highly efficient polymer solar cells with printed photoactive layer: rational process transfer from spin-coating

    KAUST Repository

    Zhao, Kui

    2016-09-05

    Scalable and continuous roll-to-roll manufacturing is at the heart of the promise of low-cost and high throughput manufacturing of solution-processed photovoltaics. Yet, to date the vast majority of champion organic solar cells reported in the literature rely on spin-coating of the photoactive bulk heterojunction (BHJ) layer, with the performance of printed solar cells lagging behind in most instances. Here, we investigate the performance gap between polymer solar cells prepared by spin-coating and blade-coating the BHJ layer for the important class of modern polymers exhibiting no long range crystalline order. We find that thickness parity does not always yield performance parity even when using identical formulations. Significant differences in the drying kinetics between the processes are found to be responsible for BHJ nanomorphology differences. We propose an approach which benchmarks the film drying kinetics and associated BHJ nanomorphology development against those of the champion laboratory devices prepared by spin-coating the BHJ layer by adjusting the process temperature. If the optimization requires the solution concentration to be changed, then it is crucial to maintain the additive-to-solute volume ratio. Emulating the drying kinetics of spin-coating is also shown to help achieve morphological and performance parities. We put this approach to the test and demonstrate printed PTB7:PC71BM polymer solar cells with efficiency of 9% and 6.5% PCEs on glass and flexible PET substrates, respectively. We further demonstrate performance parity for two other popular donor polymer systems exhibiting rigid backbones and absence of a long range crystalline order, achieving a PCE of 9.7%, the highest efficiency reported to date for a blade coated organic solar cell. The rational process transfer illustrated in this study should help the broader and successful adoption of scalable printing methods for these material systems.

  17. Synthesis and optical properties of azo -dye-attached novel second-order NLO polymers with high thermal stability

    Science.gov (United States)

    Ushiwata, Takami; Okamoto, Etsuya; Komatsu, Kyoji; Kaino, Toshikuni

    2001-06-01

    Novel second order nonlinear optical (NLO) polymethacrylate or polyacrylate polymers with high glass transition temperatures containing an azo dye attached as side-chain have been prepared using a new approach from polymethacrylic acid or polyacrylic acid as starting materials. Glass transition temperatures of 150 approximately 170 degree Celsius were obtained for Disperse red 1 dye attached polymethacrylic acid. These are attributed to the hydrogen bonding between the residual carboxyl groups in the starting polymers. Poled films by corona poling exhibited large NLO susceptibilities, (chi) (2)33 up to 53 pm/V at a wavelength of 1.3 micrometer. Due to the high glass transition temperatures of the polymers, long-term stability of the optical nonlinearity at 100 degrees Celsius was observed for 200 hrs or more. However residual carboxyl groups caused absorbance decrease mainly by hydrolysis of the ester bonds of the polymers investigated by UV-Vis absorption measurement. The stability of induced polar order of the NLO polymer was enhanced by using aminoalkyl chromophore and imidizing it thermally to introduce imide structure into the polymer main-chain. This imidized polymer exhibited (chi) (2)33 of 45 pm/V at a wavelength of 1.3 micrometer and maintained about 90% of the initial value after 230 hrs or more at 100 degrees Celsius.

  18. Magnetic field control of fluorescent polymer nanorods

    International Nuclear Information System (INIS)

    Kim, Taehyung; He, Le; Bardeen, Christopher J; Morales, Jason R; Beyermann, W P

    2011-01-01

    Nanoscale objects that combine high luminescence output with a magnetic response may be useful for probing local environments or manipulating objects on small scales. Ideally, these two properties would not interfere with each other. In this paper, we show that a fluorescent polymer host material can be doped with high concentrations of 20–30 nm diameter magnetic γ-Fe 2 O 3 particles and then formed into 200 nm diameter nanorods using porous anodic alumina oxide templates. Two different polymer hosts are used: the conjugated polymer polydioctylfluorene and also polystyrene doped with the fluorescent dye Lumogen Red. Fluorescence decay measurements show that 14% by weight loading of the γ-Fe 2 O 3 nanoparticles quenches the fluorescence of the polydioctylfluorene by approximately 33%, but the polystyrene/Lumogen Red fluorescence is almost unaffected. The three-dimensional orientation of both types of nanorods can be precisely controlled by the application of a moderate strength (∼0.1 T) external field with sub-second response times. Transmission electron microscope images reveal that the nanoparticles cluster in the polymer matrix, and these clusters may serve both to prevent fluorescence quenching and to generate the magnetic moment that rotates in response to the applied magnetic field.

  19. Luminescent zinc(ii) and copper(i) complexes for high-performance solution-processed monochromic and white organic light-emitting devices.

    Science.gov (United States)

    Cheng, Gang; So, Gary Kwok-Ming; To, Wai-Pong; Chen, Yong; Kwok, Chi-Chung; Ma, Chensheng; Guan, Xiangguo; Chang, Xiaoyong; Kwok, Wai-Ming; Che, Chi-Ming

    2015-08-01

    The synthesis and spectroscopic properties of luminescent tetranuclear zinc(ii) complexes of substituted 7-azaindoles and a series of luminescent copper(i) complexes containing 7,8-bis(diphenylphosphino)-7,8-dicarba- nido -undecaborate ligand are described. These complexes are stable towards air and moisture. Thin film samples of the luminescent copper(i) complexes in 2,6-dicarbazolo-1,5-pyridine and zinc(ii) complexes in poly(methyl methacrylate) showed emission quantum yields of up to 0.60 (for Cu-3 ) and 0.96 (for Zn-1 ), respectively. Their photophysical properties were examined by ultrafast time-resolved emission spectroscopy, temperature dependent emission lifetime measurements and density functional theory calculations. Monochromic blue and orange solution-processed OLEDs with these Zn(ii) and Cu(i) complexes as light-emitting dopants have been fabricated, respectively. Maximum external quantum efficiency (EQE) of 5.55% and Commission Internationale de l'Eclairage (CIE) coordinates of (0.16, 0.19) were accomplished with the optimized Zn-1 -OLED while these values were, respectively 15.64% and (0.48, 0.51) for the optimized Cu-3 -OLED. Solution-processed white OLEDs having maximum EQE of 6.88%, CIE coordinates of (0.42, 0.44), and colour rendering index of 81 were fabricated by using these luminescent Zn(ii) and Cu(i) complexes as blue and orange light-emitting dopant materials, respectively.

  20. High-performance ferroelectric memory based on phase-separated films of polymer blends

    KAUST Repository

    Khan, Yasser; Bhansali, Unnat Sampatraj; Almadhoun, Mahmoud N.; Odeh, Ihab N.; Cha, Dong Kyu; Alshareef, Husam N.

    2013-01-01

    High-performance polymer memory is fabricated using blends of ferroelectric poly(vinylidene-fluoride-trifluoroethylene) (P(VDF-TrFE)) and highly insulating poly(p-phenylene oxide) (PPO). The blend films spontaneously phase separate into amorphous PPO nanospheres embedded in a semicrystalline P(VDF-TrFE) matrix. Using low molecular weight PPO with high miscibility in a common solvent, i.e., methyl ethyl ketone, blend films are spin cast with extremely low roughness (Rrms ≈ 4.92 nm) and achieve nanoscale phase seperation (PPO domain size < 200 nm). These blend devices display highly improved ferroelectric and dielectric performance with low dielectric losses (<0.2 up to 1 MHz), enhanced thermal stability (up to ≈353 K), excellent fatigue endurance (80% retention after 106 cycles at 1 KHz) and high dielectric breakdown fields (≈360 MV/m). © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.