Monocrystalline silicon photovoltaic luminescent solar concentrator with 4.2% power conversion efficiency

NARCIS (Netherlands)

Desmet, L.; Ras, A.J.M.; Boer, de D.K.G.; Debije, M.G.

2012-01-01

We report conversion efficiencies of experimental single and dual light guide luminescent solar concentrators. We have built several 5¿¿cm×5¿¿cm and 10¿¿cm×10¿¿cm luminescent solar concentrator (LSC) demonstrators consisting of c-Si photovoltaic cells attached to luminescent light guides of Lumogen

Novel Sr{sub 2}LuF{sub 7}–SiO{sub 2} nano-glass-ceramics: Structure and up-conversion luminescence

Energy Technology Data Exchange (ETDEWEB)

Yanes, A.C.; Castillo, J. del, E-mail: fjvargas@ull.edu.es; Luis, D.; Puentes, J.

2016-02-15

Novel transparent nano-glass-ceramics comprising RE-doped Sr{sub 2}LuF{sub 7} nanocrystals have been obtained by thermal treatment of precursor sol–gel glasses. The precipitated Sr{sub 2}LuF{sub 7} nanocrystals with sizes from 4.5 to 11.5 nm, confirmed by X-Ray Diffraction and Transmission Electron Microscopy images, show a cubic phase structure. The luminescent features of Eu{sup 3+} ions, used as structural probes, evidence the distribution of RE ions into the fluoride nanocrystals. Under 980 nm laser excitation, intense UV, vis and NIR up-conversion emissions were observed and studied in Yb{sup 3+}–Tm{sup 3+}, Yb{sup 3+}–Er{sup 3+} and Yb{sup 3+}–Ho{sup 3+} co-doped nano-glass-ceramics. These results suggest considering these nano-glass-ceramics for potential optical applications as high efficient UV up-conversion materials in UV solid state lasers, infrared tuneable phosphors and photonic integrated devices. - Highlights: • Novel sol-gel glass-ceramics with RE{sup 3+}-Sr{sub 2}LuF{sub 7} doped nanocrystals were obtained. • Eu{sup 3+} probe ion was used to distinguish between amorphous and crystalline environments. • The incorporation of an important fraction of RE ions into nanocrystals was confirmed. • Under 980 nm excitation, intense UV-vis-NIR up-conversion emissions were observed.

Color-tunable up-conversion emission of luminescent-plasmonic, core/shell nanomaterials – KY{sub 3}F{sub 10}:Yb{sup 3+},Tm{sup 3+}/SiO{sub 2}-NH{sub 2}/Au

Energy Technology Data Exchange (ETDEWEB)

Runowski, Marcin, E-mail: runowski@amu.edu.pl

2017-06-15

Multifunctional luminescent-plasmonic KY{sub 3}F{sub 10}:Yb{sup 3+},Tm{sup 3+}/SiO{sub 2}-NH{sub 2}/Au nanomaterials were successfully obtained. The lanthanide-doped fluoride nanoparticles (NPs), synthesized under hydrothermal conditions exhibited bright blue up-conversion luminescence (λ{sub ex}=980 nm). Such lanthanide nanocrystals (20–40 nm) were coated with amine modified silica shell, forming core/shell nanostructures. Their surface was further uniformly covered with ultra-small gold NPs (4–7 nm). The as-prepared luminescent-plasmonic core/shell nanomaterials exhibited tunable up-conversion emission, due to the interactions between plasmonic and luminescent phases. The emission of Tm{sup 3+} ion was affected by the surface Au NPs, which exhibited strong plasmonic absorption in the visible range (450–650 nm). The increasing amount of the surface Au NPs, led to the significant alterations in a ratio of the Tm{sup 3+} emission bands. The NIR band ({sup 3}H{sub 4}→{sup 3}H{sub 6}) was unchanged, whereas the ratio and relative intensity of the bands in a visible range ({sup 1}G{sub 4}→{sup 3}H{sub 6} and {sup 1}G{sub 4}→{sup 3}F{sub 4}) was altered. This led to the significant change of the emission spectra shape and influenced color of emission, tuning it from bright blue to blue-violet. The products obtained were characterized by transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX), powder X-ray diffraction (XRD), UV–vis absorption spectroscopy and luminescence spectroscopy (excitation/emission spectra and luminescence decay curves).

Luminescence properties in the visible of Dy:YAG/YAG planar waveguides

Energy Technology Data Exchange (ETDEWEB)

Klimczak, M., E-mail: m.klimczak@elka.pw.edu.p [Institute of Microelectronics and Optoelectronics, Koszykowa 75, 00-662 Warsaw (Poland); Malinowski, M. [Institute of Microelectronics and Optoelectronics, Koszykowa 75, 00-662 Warsaw (Poland); Institute of Electronic Materials Technology, Wolczynska 133, 01-919 Warsaw (Poland); Sarnecki, J. [Institute of Electronic Materials Technology, Wolczynska 133, 01-919 Warsaw (Poland); Piramidowicz, R. [Institute of Microelectronics and Optoelectronics, Koszykowa 75, 00-662 Warsaw (Poland); Telekomunikacja Polska Research and Development Centre, Obrzezna 7, 02-691 Warsaw (Poland)

2009-12-15

In this work, we investigate visible emission properties of dysprosium-doped yttrium aluminum garnet (YAG) waveguides prepared by the liquid phase epitaxy (LPE) method, which allowed obtaining samples of activator concentrations ranging from 0.2 at% up to ca. 18 at%. This unique set of Dy:YAG/YAG waveguides has been carefully examined by means of highly resolved laser spectroscopy to explore the luminescence properties in the visible (yellow-blue) part of spectrum. In particular, the low-temperature absorption spectra have been recorded and analyzed, giving a more detailed information on energy levels' positions in these crystals. The concentration-dependant emission spectra and fluorescence dynamics profiles have been collected under direct excitation, enabling analysis of multi-ion processes responsible for concentration quenching. This, in turn, enabled optimization of activator concentration with respect to yellow emission efficiency. Additionally, the possible IR to visible up-conversion pathways have been discussed, giving a starting point for further investigations.

Synthesis and luminescent properties of PEO/lanthanide oxide nanoparticle hybrid films

International Nuclear Information System (INIS)

Goubard, F.; Vidal, F.; Bazzi, R.; Tillement, O.; Chevrot, C.; Teyssie, D.

2007-01-01

In this study, we investigate the optical properties of lanthanide oxide nanoparticles dispersed in poly(ethylene oxide) (PEO) network as thermally stable polymeric films. The aim of this work is both to keep a good optical transparency in the visible domain and to obtain luminescent materials after incorporation of nanoparticles. For this purpose, we develop luminescent nanocrystals of oxides containing terbium ion as a doping element in Gd 2 O 3 . These sub-5-nm lanthanide oxides nanoparticles have been prepared by direct oxide precipitation in high-boiling polyalcohol solutions and characterized by luminescence spectroscopy. PEO/lanthanide oxide nanohybrid films are prepared by radical polymerization of poly(ethylene glycol) methacrylate after introduction of lanthanide oxide particles. As a first result; the obtained films present interesting luminescence properties with a very low lanthanide oxide content (up to 0.29 wt%). Furthermore, these films are still transparent and keep their original mechanical properties. Prior to describe the specific applications to optical use, we report here the dynamic mechanical analysis (DMA), X-ray diffraction (XRD) analysis, transmission electron microscopy (TEM), and luminescent properties of. nanohybrid films

Down- and up-conversion luminescent carbon dot fluid: inkjet printing and gel glass fabrication

Science.gov (United States)

Wang, Fu; Xie, Zheng; Zhang, Bing; Liu, Yun; Yang, Wendong; Liu, Chun-Yan

2014-03-01

Room temperature liquid-like nanoparticles have emerged as an exciting new research and development area, because their properties could be tailored over a broad range by manipulating geometric and chemical characteristics of the inorganic core and organic canopy. However, related applications are rarely reported due to the multi-step synthesis process and potential toxicity of cadmium based nanomaterials. In this study, we prepared inexpensive and eco-friendly carbon dot fluid by the direct thermal decomposition method. The carbon dot fluid can be excited from UV to near infrared light, and can be prepared as highly concentrated luminescent ink or incorporated into sol-gel derived organically modified silicate glass, suggesting that it has great application potential in the field of printable electronics, solid state lighting and so on.Room temperature liquid-like nanoparticles have emerged as an exciting new research and development area, because their properties could be tailored over a broad range by manipulating geometric and chemical characteristics of the inorganic core and organic canopy. However, related applications are rarely reported due to the multi-step synthesis process and potential toxicity of cadmium based nanomaterials. In this study, we prepared inexpensive and eco-friendly carbon dot fluid by the direct thermal decomposition method. The carbon dot fluid can be excited from UV to near infrared light, and can be prepared as highly concentrated luminescent ink or incorporated into sol-gel derived organically modified silicate glass, suggesting that it has great application potential in the field of printable electronics, solid state lighting and so on. Electronic supplementary information (ESI) available: Details of FTIR, XRD and DLS of CDF, optical properties of CDF, TEM images of other obtained products, luminescent spectra of CDF at different temperatures, and the optical photographs of CDF inks and silica glasses with different concentrations

Recombination luminescence from H centers and conversion of H centers into I centers in alkali iodides

International Nuclear Information System (INIS)

Berzina, B.J.

1981-01-01

The study is aimed at the search for H-plus-electron centers of luminescence and the investigation of the conversion of H- into I centers by the luminescence of H-plus-electron centers in alkali iodide crystals. KI, RbI and NaI crystals were studied at 12 K. H and F centers were created by irradiation with ultraviolet light corresponding to the absorption band of anion excitons. Then the excitation of electron centers by red light irradiation was followed. The spectra of stimulated recombination luminescence were studied. The luminescence of H-plus- electron centers had been observed and the conclusion was made that this center was formed on immobile H centers. In case of stable H centers the optically stimulated conversion of H centers into I centers occurs. The assumption is advanced on the spontaneous annihilation of near placed unstable F, H centers which leads to the creation of H-plus-electron luminescence centers and to the spontaneous H-I-centers conversion [ru

Synthesis and luminescent properties of PEO/lanthanide oxide nanoparticle hybrid films

Energy Technology Data Exchange (ETDEWEB)

Goubard, F. [LPPI, Universite de Cergy-Pontoise, 5 Mail Gay-Lussac, Neuville-sur-Oise, 95031 Cergy-Pontoise cedex (France)]. E-mail: fabrice.goubard@u-cergy.fr; Vidal, F. [LPPI, Universite de Cergy-Pontoise, 5 Mail Gay-Lussac, Neuville-sur-Oise, 95031 Cergy-Pontoise cedex (France); Bazzi, R. [LPCML, Universite Lyon 1, 43 Bd. du 11 Novembre 1918, 69622 Villeurbanne (France); Tillement, O. [LPCML, Universite Lyon 1, 43 Bd. du 11 Novembre 1918, 69622 Villeurbanne (France); Nano-H, 23 rue Royal, 69001 Lyon (France); Chevrot, C. [LPPI, Universite de Cergy-Pontoise, 5 Mail Gay-Lussac, Neuville-sur-Oise, 95031 Cergy-Pontoise cedex (France); Teyssie, D. [LPPI, Universite de Cergy-Pontoise, 5 Mail Gay-Lussac, Neuville-sur-Oise, 95031 Cergy-Pontoise cedex (France)

2007-10-15

In this study, we investigate the optical properties of lanthanide oxide nanoparticles dispersed in poly(ethylene oxide) (PEO) network as thermally stable polymeric films. The aim of this work is both to keep a good optical transparency in the visible domain and to obtain luminescent materials after incorporation of nanoparticles. For this purpose, we develop luminescent nanocrystals of oxides containing terbium ion as a doping element in Gd{sub 2}O{sub 3}. These sub-5-nm lanthanide oxides nanoparticles have been prepared by direct oxide precipitation in high-boiling polyalcohol solutions and characterized by luminescence spectroscopy. PEO/lanthanide oxide nanohybrid films are prepared by radical polymerization of poly(ethylene glycol) methacrylate after introduction of lanthanide oxide particles. As a first result; the obtained films present interesting luminescence properties with a very low lanthanide oxide content (up to 0.29 wt%). Furthermore, these films are still transparent and keep their original mechanical properties. Prior to describe the specific applications to optical use, we report here the dynamic mechanical analysis (DMA), X-ray diffraction (XRD) analysis, transmission electron microscopy (TEM), and luminescent properties of. nanohybrid films.

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) ...

Tm2+ luminescent materials for solar radiation conversion devices

NARCIS (Netherlands)

Van der Kolk, E.

2015-01-01

A solar radiation conversion device is described that comprises a luminescent Tm 2+ inorganic material for converting solar radiation of at least part of the UV and/or visible and/or infra red solar spectrum into infrared solar radiation, preferably said infrared solar radiation having a wavelength

Conversion of invisible metal-organic frameworks to luminescent perovskite nanocrystals for confidential information encryption and decryption.

Science.gov (United States)

Zhang, Congyang; Wang, Bo; Li, Wanbin; Huang, Shouqiang; Kong, Long; Li, Zhichun; Li, Liang

2017-10-31

Traditional smart fluorescent materials, which have been attracting increasing interest for security protection, are usually visible under either ambient or UV light, making them adverse to the potential application of confidential information protection. Herein, we report an approach to realize confidential information protection and storage based on the conversion of lead-based metal-organic frameworks (MOFs) to luminescent perovskite nanocrystals (NCs). Owing to the invisible and controlled printable characteristics of lead-based MOFs, confidential information can be recorded and encrypted by MOF patterns, which cannot be read through common decryption methods. Through our conversion strategy, highly luminescent perovskite NCs can be formed quickly and simply by using a halide salt trigger that reacts with the MOF, thus promoting effective information decryption. Finally, through polar solvents impregnation and halide salt conversion, the luminescence of the perovskite NCs can be quenched and recovered, leading to reversible on/off switching of the luminescence signal for multiple information encryption and decryption processes.

The effect of intentional potassium co-doping on the luminescent properties of Yb3+ and Tm3+ doped α-NaYF4 core and core–shell nanoparticles

International Nuclear Information System (INIS)

Misiak, Małgorzata; Stręk, Wiesław; Arabasz, Sebastian; Bednarkiewicz, Artur

2016-01-01

Simple and effective ways to circumvent limited luminescence efficiency of up-converting nanoparticles (UCNPs) are sought. One of the methods relays on distorting the crystallographic structure of host material by co-doping the nanocrystals with optically inactive co-dopants. Here we study the influence of K + doping and surface passivation on the up-converting properties of the α-NaYF 4 nanocrystals co-doped with 20% Yb 3+ and 0.1 or 2% Tm 3+ . The intentionally chosen concentrations of K + ions, which were meant to replaced sodium ions were fixed to 0, 5, 10, 20 to 30%. Potassium ions modified the spectroscopic properties of both core and core–shell NPs, but the differences were noticed between samples doped with 0.1% Tm 3+ and 2% Tm 3+ ions. Replacement of sodium by potassium ions decreased up-conversion luminescence intensity as well as shortened thulium excited states lifetimes in the samples doped with 0.1% Tm 3+ , while the opposite behavior was found in the samples co-doped with higher 2% thulium concentration. - Highlights: • We studied the influence of K + doping on luminescent properties of α-NaYF 4 :YbTm. • The 0.1 and 2% Tm doped core and core–shell samples were investigated. • K + -doping influence on UC properties was different in low and highly Tm doped NPs. • The explanations of the observed variations were proposed.

Hydrothermal synthesis, characterization and luminescent ...

Indian Academy of Sciences (India)

Home; Journals; Bulletin of Materials Science; Volume 39; Issue 4. Hydrothermal synthesis, characterization and luminescent properties of lanthanide-doped NaLaF 4 nanoparticles. JIGMET LADOL HEENA KHAJURIA SONIKA KHAJURIA ... Keywords. Citric acid; X-ray diffraction; down-conversion emission; energy transfer.

Photon up-conversion production in Tb{sup 3+}–Yb{sup 3+} co-doped CaF{sub 2} phosphors prepared by combustion synthesis

Energy Technology Data Exchange (ETDEWEB)

Rakov, Nikifor, E-mail: nikifor.gomez@univasf.edu.br [PG—Ciência dos Materiais, Universidade Federal do Vale do São Francisco, 48902-300 Juazeiro, BA (Brazil); Guimarães, Renato B. [Instituto de Física, Universidade Federal Fluminense, 24210-346 Niterói, RJ (Brazil); Maciel, Glauco S., E-mail: glauco@if.uff.br [Instituto de Física, Universidade Federal Fluminense, 24210-346 Niterói, RJ (Brazil)

2016-02-15

Graphical abstract: Up-conversion luminescence from Tb{sup 3+} obtained by energy transfer from Yb{sup 3+} pairs in CaF{sub 2} powder prepared by combustion synthesis. - Highlights: • Calcium fluoride (CaF{sub 2}) powders were prepared by combustion synthesis. • Rare-earth ions doped in this material were found in interstitial sites. • Cooperative up-conversion was observed in Tb{sup 3+}:Yb{sup 3+}:CaF{sub 2} powder. • Energy transfer between Tb{sup 3+} and pairs of Yb{sup 3+} was analyzed using rate equations. - Abstract: Calcium fluoride (CaF{sub 2}) crystalline powders were successfully prepared by the combustion synthesis method. The powder material containing luminescent rare-earth ions, more specifically terbium (Tb{sup 3+}) and ytterbium (Yb{sup 3+}), was studied by X-ray diffraction, scanning electronic microscopy and optical spectroscopy. These ions are allocated in charge compensated interstitial positions of tetragonal (C{sub 4v}) and trigonal (C{sub 3v}) symmetry sites of the cubic (O{sub h}) CaF{sub 2} lattice. Up-conversion (UC) luminescence in Tb{sup 3+} was achieved using a low power diode laser operating at 975 nm. Tb{sup 3+} is insensitive to near-infrared radiation but UC can be achieved via energy transfer from pairs of Yb{sup 3+} ions to Tb{sup 3+} ions. The UC luminescence dynamics of Tb{sup 3+} was used to study the energy transfer mechanism.

Luminescence properties of some food dye-stuffs

International Nuclear Information System (INIS)

Astanov, S.Kh.; Muminova, Z.A.; Urunov, R.G.

2004-01-01

The luminescence properties of the natural food dye-stuffs and vitamins in temperature range of 300-5.2 K are studied. On the basis of experimental data on quantum yields of the fluorescence, trans-cis-isomerization and luminescence of the molecular oxygen the main ways of the inactivation of electronic excitations in researching compounds have been defined. (author)

Infrared up-conversion microscope

DEFF Research Database (Denmark)

2014-01-01

There is presented an up-conversion infrared microscope (110) arranged for imaging an associated object (130), wherein the up-conversion infrared microscope (110) comprises a non-linear crystal (120) arranged for up-conversion of infrared electromagnetic radiation, and wherein an objective optical...

Infrared up-conversion telescope

DEFF Research Database (Denmark)

2014-01-01

There is presented to an up-conversion infrared telescope (110) arranged for imaging an associated scene (130), wherein the up-conversion infrared telescope (110) comprises a non-linear crystal (120) arranged for up-conversion of infrared electromagnetic radiation, and wherein a first optical...

Luminescence properties of a nanoporous freshwater diatom.

Science.gov (United States)

Goswami, Bondita; Choudhury, Amarjyoti; Buragohain, Alak K

2012-01-01

Freshwater diatom frustules show special optical properties. In this paper we observed luminescence properties of the freshwater diatom Cyclotella meneghiniana. To confirm the morphological properties we present scanning electron microscopy (SEM) images. X-ray diffraction (XRD) studies were carried out to visualize the structural properties of the frustules, confirming that silica present in diatom frustules crystallizes in an α-quartz structure. Study of the optical properties of the silica frustules of diatoms using ultra-violet-visible (UV-vis) spectroscopy and photoluminescence spectroscopy confirmed that the diatom C. meneghiniana shows luminescence in the blue region of the electromagnetic spectrum when irradiated with UV light. This property of diatoms can be exploited to obtain many applications in day-to-day life. Also, using time-resolved photoluminescence spectroscopy (TRPL) it was confirmed that this species of diatom shows bi-exponential decay. Copyright © 2011 John Wiley & Sons, Ltd.

Luminescence and the light emitting diode the basics and technology of leds and the luminescence properties of the materials

CERN Document Server

Williams, E W; Pamplin, BR

2013-01-01

Luminescence and the Light Emitting Diode: The Basics and Technology of LEDS and the Luminescence Properties of the Materials focuses on the basic physics and technology of light emitting diodes (LEDS) and pn junction lasers as well as their luminescence properties. Optical processes in semiconductors and the useful devices which can be made are discussed. Comprised of 10 chapters, this book begins with an introduction to the crystal structure and growth, as well as the optical and electrical properties of LED materials. The detailed fabrication of the LED is then considered, along with the lu

Luminescence properties of Tm3+ ions single-doped YF3 materials in an unconventional excitation region.

Science.gov (United States)

Chen, Yuan; Liu, Qing; Lin, Han; Yan, Xiaohong

2018-05-01

According to the spectral distribution of solar radiation at the earth's surface, under the excitation region of 1150 to 1350 nm, the up-conversion luminescence of Tm 3+ ions was investigated. The emission bands were matched well with the spectral response region of silicon solar cells, achieved by Tm 3+ ions single-doped yttrium fluoride (YF 3 ) phosphor, which was different from the conventional Tm 3+ /Yb 3+ ion couple co-doped materials. Additionally, the similar emission bands of Tm 3+ ions were achieved under excitation in the ultraviolet region. It is expected that via up-conversion and down-conversion routes, Tm 3+ -sensitized materials could convert photons to the desired wavelengths in order to reduce the energy loss of silicon solar cells, thereby enhancing the photovoltaic efficiency. Copyright © 2018 John Wiley & Sons, Ltd.

Highly uniform up-converting nanoparticles: Why you should control your synthesis even more

International Nuclear Information System (INIS)

Palo, Emilia; Tuomisto, Minnea; Hyppänen, Iko; Swart, Hendrik C.; Hölsä, Jorma; Soukka, Tero; Lastusaari, Mika

2017-01-01

Luminescent β-NaYF 4 :Yb 3+ ,Er 3+ (x Yb : 0.17, x Er : 0.03) nanomaterials were synthesized for use as labels for biomedical applications with high temperature co-precipitation synthesis in 1-octadecene and oleic acid. The effect of the synthesis conditions (e.g. argon flow, cooling and stirring rates) on the products’ up-conversion luminescence intensity, particle size and morphology were studied. The factors contributing to these properties were analysed. It was observed that an efficient inert gas flow is essential to the formation of the preferred highly-luminescent hexagonal structure. Furthermore, the flow rate, together with the stirring rate, crucially affect the Er:Yb molar ratio of the products. The optimization of this ratio is essential when strong up-conversion emission is required from small particles, whereas the morphology and uniformity of the nanoparticles can be controlled with the cooling rate. These results emphasize the importance of controlling the synthesis conditions, especially when nanoparticles need to have a specific morphology because of their use e.g. as luminescent labels in medical diagnostics.

Highly uniform up-converting nanoparticles: Why you should control your synthesis even more

Energy Technology Data Exchange (ETDEWEB)

Palo, Emilia, E-mail: ekharj@utu.fi [University of Turku, Department of Chemistry, FI-20014 Turku (Finland); University of Turku Graduate School (UTUGS), Doctoral Programme in Physical and Chemical Sciences, Turku (Finland); Turku University Centre for Materials and Surfaces (MatSurf), Turku (Finland); Tuomisto, Minnea [University of Turku, Department of Chemistry, FI-20014 Turku (Finland); University of Turku Graduate School (UTUGS), Doctoral Programme in Physical and Chemical Sciences, Turku (Finland); Turku University Centre for Materials and Surfaces (MatSurf), Turku (Finland); Hyppänen, Iko [University of Turku, Department of Chemistry, FI-20014 Turku (Finland); Turku University Centre for Materials and Surfaces (MatSurf), Turku (Finland); Swart, Hendrik C.; Hölsä, Jorma [University of the Free State, Department of Physics, Bloemfontein ZA-9300 (South Africa); Soukka, Tero [University of Turku, Department of Biochemistry, FI-20014 Turku (Finland); Lastusaari, Mika [University of Turku, Department of Chemistry, FI-20014 Turku (Finland); Turku University Centre for Materials and Surfaces (MatSurf), Turku (Finland)

2017-05-15

Luminescent β-NaYF{sub 4}:Yb{sup 3+},Er{sup 3+} (x{sub Yb}: 0.17, x{sub Er}: 0.03) nanomaterials were synthesized for use as labels for biomedical applications with high temperature co-precipitation synthesis in 1-octadecene and oleic acid. The effect of the synthesis conditions (e.g. argon flow, cooling and stirring rates) on the products’ up-conversion luminescence intensity, particle size and morphology were studied. The factors contributing to these properties were analysed. It was observed that an efficient inert gas flow is essential to the formation of the preferred highly-luminescent hexagonal structure. Furthermore, the flow rate, together with the stirring rate, crucially affect the Er:Yb molar ratio of the products. The optimization of this ratio is essential when strong up-conversion emission is required from small particles, whereas the morphology and uniformity of the nanoparticles can be controlled with the cooling rate. These results emphasize the importance of controlling the synthesis conditions, especially when nanoparticles need to have a specific morphology because of their use e.g. as luminescent labels in medical diagnostics.

Luminescence properties of uranyl-acetate species

Energy Technology Data Exchange (ETDEWEB)

Brinkmann, Hannes; Moll, Henry [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Inst. of Resource Ecology; Stumpf, Thorsten [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Biogeochemistry

2017-06-01

Time-resolved laser-induced fluorescence spectroscopy (TRLFS) was applied to characterize uranium(VI)- acetate species based on their luminescence properties. In contrast to previous interpretations, no indications were detected for the existence of the 1: 3 complex.

Novel lanthanide doped micro- and mesoporous solids. Characterization of ion-host-interactions, species distribution and luminescence properties using time-resolved luminescence spectroscopy

International Nuclear Information System (INIS)

Gessner, Andre

2010-12-01

easily accessible for water and thus show shorter luminescence decay times and a more symmetrical coordination sphere, which is mostly made up by water molecules. Another investigated aspect was the influence of surface modifications on the luminescence behavior of the lanthanide ions inside the material. Here we could show, that surface modifications hydrophobize the material and thus are able to protect the lanthanide ions from water, which is important for the conservation of the luminescence properties. Concerning the mesoporous silicates, again a heterogeneous distribution of the lanthanide ions in the pore system was found. A part of the lanthanide ions interacts with the pore wall, while the other part is located in the aqueous phase inside the pores. Surface modification led to a interaction of the lanthanide ions with the modification. This was reflected in the luminescence properties depending on the structure of the modification and the surface loading.

Characterization and luminescent properties of thermally annealed olivines

International Nuclear Information System (INIS)

Colin-Garcia, Maria; Correcher, Virgilio; Garcia-Guinea, Javier; Heredia-Barbero, Alejandro; Roman-Lopez, Jesus; Ortega-Gutierrez, Fernando; Negron-Mendoza, Alicia; Ramos-Bernal, Sergio

2013-01-01

Olivine is an iron-magnesium solid solution silicate (Mg,Fe) 2 SiO 4 and it is probably one of the most abundant mineral phase in the Solar System, it is present in the primitive carbonaceous meteorites (i.e Allende), and in ordinary chondritic meteorite, comets or terrestrial planets. The olivine grains in those bodies have been exposed to different radiation sources like UV, electrons, cosmic radiation, etc. Here, we explore the effect of ionizing and non ionizing radiation on the luminescence emission of the two well-characterised olivine samples from Mexico and Spain by means of cathodoluminescence and thermoluminescence. The analyses by X-ray dispersive energies in the scanning electron microscopy show differences between the samples in the amount of iron and magnesium and also show traces of rare elements. Olivine exhibits spectral cathodoluminescence emissions of low intensity, explained for the quenching of the luminescence of the iron, and sharp signals assigned as impurities. Cathodoluminescence and thermoluminescence glow curves of the natural, and UV induced olivine samples were obtained. Our results show that thermal treatments at 1100 °C change the mineral molecular structure and the luminescence properties of this mineral phase. These results confirm an active participation of physical factors influencing the luminescent properties of olivine. -- Highlights: ► Luminescent properties of two olivines samples (Mexican and Spanish) were explored. ► EDS show different iron and magnesium content and traces of rare elements on both. ► Olivine exhibits spectral CL emissions of low intensity due to the quenching of iron. ► Treatments at 1100 °C change the mineral structure and its response to UV radiation

Hydrothermal synthesis, characterization and luminescent ...

Indian Academy of Sciences (India)

that nanoparticles have cylindrical shape and crystalline nature of nanoparticles was confirmed by SAED patterns. Down- conversion (DC) luminescent properties of doped NaLaF4 were also .... Figure 1 shows the XRPD patterns of undoped NaLaF4 and .... which can be assigned to the transitions from the 7F6 ground.

Luminescence properties of Yb:Nd:Tm:KY3F10 nanophosphor and thermal treatment effects

International Nuclear Information System (INIS)

Gomes, Laércio; Linhares, Horácio Marconi da Silva M.D.; Ichikawa, Rodrigo Uchida; Martinez, Luis Gallego; Ranieri, Izilda Marcia

2015-01-01

In this work, we present the spectroscopic properties of KY 3 F 10 (KY3F) nanocrystals activated with thulium and codoped with ytterbium and neodymium ions. The most important processes that lead to the thulium upconversion emissions in the blue region were identified. A time-resolved luminescence spectroscopy technique was employed to measure the luminescence decays and to determine the most important mechanisms involved in the upconversion process that populates 1 G 4 (Tm 3+ ) excited states. Analysis of the energy-transfer processes dynamics using selective pulsed-laser excitations in Yb:Nd:Tm, Nd:KY3F nanocrystals shows that the direct energy transfer from Nd 3+ to Tm 3+ ions is the mechanism responsible for the 78% of the blue upconversion luminescence in the Yb:Nd:Tm:KY3F when compared with the Yb:Nd:Tm:KY3F bulk crystal for an laser excitation at 802 nm. An investigation of the 1 G 4 level luminescence kinetic of Tm 3+ in Yb/Nd/Tm system revealed that the luminescence efficiency ( 1 G 4 ) starts with a very low value (0.38%) for the synthesized nanocrystal (as grown) and strongly increases to 97% after thermal treatment at 550 °C for 6 h under argon flow. As a consequence of the thermal treatment at T=550 °C, the contributions of the (Nd×Tm) (Up 1 ) and (Nd×Yb×Tm) (Up 2 ) upconversion processes to the 1 G 4 luminescence are 33% (Up 1 ) and 67% for Up 2 . Up 2 process represented by Nd 3+ ( 4 F 3/2 )→Yb 3+ ( 2 F 7/2 ) followed by Yb 3+ ( 2 F 5/2 )→Tm ( 3 H 4 )→Tm 3+ ( 1 G 4 ) was previously reported as the main mechanism to produce the blue luminescence in Yb:Nd:Tm:YLiF 4 and KY 3 F 10 bulk crystals. Results of X-ray diffraction analysis of nanopowder using the Rietveld method reveled that crystallite sizes remain unchanged (12–14 nm) after thermal treatments with T≤400 °C, while the 1 G 4 luminescence efficiency strongly increases from 0.38% (T=25 °C) to 12% (T=400 °C). Results shown that the Nd 3+ ions distribution has a concentration

Preparation and up-conversion luminescence of SrAlF{sub 5}:Yb{sup 3+}/Er{sup 3+} nanorods

Energy Technology Data Exchange (ETDEWEB)

Zhao, Jun [College of Life Science, Dalian Nationalities University, Dalian, Liaoning 116600 (China); Department of Physics, Dalian Maritime University, Dalian, Liaoning 116026 (China); Hua, Ruinian, E-mail: rnhua@dlnu.edu.cn [College of Life Science, Dalian Nationalities University, Dalian, Liaoning 116600 (China); Zhang, Wei; Feng, Zhiqing; Tang, Dongxin; Na, Liyan [College of Life Science, Dalian Nationalities University, Dalian, Liaoning 116600 (China); Chen, Baojiu, E-mail: chenmbj@sohu.com [Department of Physics, Dalian Maritime University, Dalian, Liaoning 116026 (China)

2014-03-05

Graphical abstract: The SrAlF{sub 5} nanorods co-doped with various Yb{sup 3+}/Er{sup 3+} concentrations was synthetized via a microemulsion-hydrothermal process for the first time. It was found that the optimum doping concentration of Yb{sup 3+} and Er{sup 3+} in SrAlF{sub 5} matrix was about 4 mol%. Furthermore, the temperature effect of upconversion luminescence was investigated. It was also found that the post heat-treatment could greatly improve upconversion luminescence. Highlights: • SrAlF{sub 5}:Yb{sup 3+}/Er{sup 3+} nanorods were synthesized via a microemulsion-hydrothermal process. • Crystal structure and morphology were characterized by using XRD and FESEM. • The upconversion luminescence intensity depend on LD working current was studied. • The post heat-treatment could greatly improve upconversion luminescence. -- Abstract: Yb{sup 3+} and Er{sup 3+} co-doped SrAlF{sub 5} nanorods with average diameter of 35 nm and average length of 400 nm were synthesized via a microemulsion-hydrothermal process, and their crystal structure and morphology were characterized by using X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM), respectively. The optimum doping concentration of Yb{sup 3+}/Er{sup 3+} in SrAlF{sub 5} matrix was about 4 mol%. The upconversion luminescence intensity dependence on the laser diode (LD) working current was studied and the possible upconversion mechanism was analyzed. Furthermore, the temperature effect of upconversion luminescence was investigated. It was also found that the post heat-treatment could greatly improve upconversion luminescence.

Construction of a system for up-conversion detection in vitroceramics doped with rare earths

International Nuclear Information System (INIS)

Santa Cruz, P.A.; Azevedo, W.M. de; Sa, G.F. de

1983-01-01

A system capable of detecting up-conversion processes by energy transference or cooperative luminescence was developed. Pulverized vitroceramic samples containing PbF 2 and GeO 2 , doped with Yb 2 O 3 as sensitizer and Tm 2 O 3 or Er 2 O 3 as activator, were used. A diagram of the detection system, as well as graphs showing the variation of the emission intensity of these doped vitroceramics as a function of excitation intensity (970 mn), are presented. (C.L.B.) [pt

Fabrication and Spectral Properties of Wood-Based Luminescent Nanocomposites

Directory of Open Access Journals (Sweden)

Xianjun Li

2014-01-01

Full Text Available Pressure impregnation pretreatment is a conventional method to fabricate wood-based nanocomposites. In this paper, the wood-based luminescent nanocomposites were fabricated with the method and its spectral properties were investigated. The results show that it is feasible to fabricate wood-based luminescent nanocomposites using microwave modified wood and nanophosphor powders. The luminescent strength is in positive correlation with the amount of phosphor powders dispersed in urea-formaldehyde resin. Phosphors absorb UV and blue light efficiently in the range of 400–470 nm and show a broad band of bluish-green emission centered at 500 nm, which makes them good candidates for potential blue-green luminescent materials.

Improved luminescence properties of nanocrystalline silicon based electroluminescent device by annealing

International Nuclear Information System (INIS)

Sato, Keisuke; Hirakuri, Kenji

2006-01-01

We report an annealing effect on electrical and luminescence properties of a red electroluminescent device consisting of nanocrystalline silicon (nc-Si). The red luminescence was generated by flowing the forward current into the device at a low threshold direct current (DC) forward voltage with a rise of annealing temperature up to 500 deg. C. Moreover, the luminescence of the device annealed at 500 deg. C was more intense than that of the device annealed at 200 deg. C or less under the same forward current density, because of the injection of a large quantity of carriers to the radiative recombination centers at the nc-Si surface vicinity. These were attained by a low resistivity of indium tin oxide (ITO) electrode and good contact at the ITO electrode/luminous layer interface region by the annealing treatment. The above results indicated that the annealing treatment of the device is effective for the realization of high luminance due to the improvement in the injection efficiency of carriers to the radiative recombination centers

Photoluminescence, reddish orange long persistent luminescence and photostimulated luminescence properties of praseodymium doped CdGeO3 phosphor

International Nuclear Information System (INIS)

Jin, Yahong; Hu, Yihua; Chen, Li; Fu, Yinrong; Mu, Zhongfei; Wang, Tao; Lin, Jun

2014-01-01

Highlights: • A novel phosphor CdGeO 3 :Pr 3+ was synthesized successfully. • The persistent luminescence properties of CdGeO 3 :Pr 3+ were studied. • The photostimulated luminescence properties of CdGeO 3 :Pr 3+ were investigated. • The persistent and photostimulated luminescence mechanisms were discussed in detail. - Abstract: Praseodymium doped CdGeO 3 phosphors were prepared successfully by a conventional high temperature solid-state reaction method. It showed reddish orange long persistent luminescence (LPL) after the short UV-irradiation. The reddish orange photostimulated luminescence (PSL) was also observed upon near infrared stimulation at 980 nm after per-exposure into UV light. The origin of LPL and PSL was identified with the emission from Pr 3+ ions with the aid of traps in host lattice. The optimal concentration of Pr 3+ ions for the brightest photoluminescence (PL) emission and the best LPL characteristic were experimentally to be about 3% and 0.5 mol%, respectively. The trapping and de-trapping processes of charge carriers between shallower and deep traps were illustrated. A model was proposed on the basis of experimental results to study the mechanisms of LPL and PSL

Visible and near infrared up-conversion luminescence in Yb3+/Tm3+ co-doped yttria-alumino-silicate glass based optical fibers

International Nuclear Information System (INIS)

Halder, Arindam; Chandra Paul, Mukul; Wadi Harun, Sulaiman; Kumar Bhadra, Shyamal; Bysakh, Sandip; Das, Shyamal; Pal, Mrinmay

2013-01-01

We report blue light up-conversion (UC) emission in Yb–Tm co-doped nano-phase separated yttria-alumino-silicate (YAS) glass based D-shaped with low-index cladding optical fibers. Y 2 O 3 creates an environment of nano structured YAS glass phases with Yb and Tm rich zone into the core glass which confirmed from TEM analyses. This kind of glass host assists in distributing of Yb and Tm rich zone uniformly throughout the core region. Yb and Tm doped regions exist mainly into nano YAS phases, defined as RE rich nano YAS-RE phases. All samples exhibit UC luminescence peaks at 483 nm, 650 nm and 817 nm for Tm 3+ and 1044 nm for Yb 3+ under excitation by 975 nm laser light. In such type of nano-engineered glass–ceramic based host, almost all the Yb ions transferred its energy to the nearer Tm ions. In particular 483 nm emission is attributed to 1 G 4 → 3 H 6 transition through a three step resonance energy transfer (ET) from excited Yb 3+ . The highest emission intensity is obtained with a concentration of 0.5 wt% Tm 3+ and 2.0 wt% Yb 3+ . The ET between Yb 3+ and Tm 3+ is increased with increase of Yb 3+ concentration with respect to Tm 3+ . The experimental fluorescence life-times of Tm 3+ upconversion emission at visible wavelengths into such kind of fiber is reported under 975 nm pump excitation. The present study is important for development of an efficient tunable 483 nm fluorescence light source. -- Highlights: • We report nano-phase separated YAS glass host based Yb–Tm co-doped optical fibers. • Almost all the Yb transferred its energy to the neighboring Tm ions. • We report strong UC luminescence peaks at 483 nm and 817 nm wavelengths. • We report third ET coefficient as 1.6723 Hz for such kind of Yb–Tm codoped fiber. • We report suitable fiber as an efficient tunable 483 nm fluorescence light source

The effect of thermal oxidation on the luminescence properties of nanostructured silicon.

Science.gov (United States)

Liu, Lijia; Sham, Tsun-Kong

2012-08-06

Herein is reported a detailed study of the luminescence properties of nanostructured Si using X-ray excited optical luminescence (XEOL) in combination with X-ray absorption near-edge structures (XANES). P-type Si nanowires synthesized via electroless chemical etching from Si wafers of different doping levels and porous Si synthesized using electrochemical method are examined under X-ray excitation across the Si K-, L(3,2) -, and O K-edges. It is found that while as-prepared Si nanostructures are weak light emitters, intense visible luminescence is observed from thermally oxidized Si nanowires and porous Si. The luminescence mechanism of Si upon oxidation is investigated by oxidizing nanostructured Si at different temperatures. Interestingly, the two luminescence bands observed show different response with the variation of absorption coefficient upon Si and O core-electron excitation in elemental silicon and silicon oxide. A correlation between luminescence properties and electronic structures is thus established. The implications of the finding are discussed in terms of the behavior of the oxygen deficient center (OCD) and non-bridging oxygen hole center (NBOHC). Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Luminescent and structural properties of Zn_xMg_1_-_xWO_4 mixed crystals

International Nuclear Information System (INIS)

Krutyak, N.; Nagirnyi, V.; Spassky, D.; Tupitsyna, I.; Dubovik, A.; Belsky, A.

2016-01-01

The structural and luminescent properties of perspective scintillating Zn_xMg_1_-_xWO_4 mixed crystals were studied. The following characteristics were found to depend linearly on x value: the energy of several vibrational modes detected by Raman spectroscopy, the bandgap width deduced from the shift of the excitation spectrum onset of a self-trapped exciton (STE) emission, the position of thermally stimulated luminescence peaks. It is also shown that the thermal stability of the STE luminescence decreases gradually when x decreases. These data indicate that each Zn_xMg_1_-_xWO_4 mixed crystal is not a mixture of two constituents, but possesses its original crystalline structure, as well as optical and luminescent properties. - Highlights: • The structural and luminescent properties of Zn_xMg_1_-_xWO_4 were studied. • The energy of Raman modes, the bandgap width, TSL peak position linearly depend on x. • Each Zn_xMg_1_-_xWO_4 possesses its original crystalline structure.

Enhancing and quenching luminescence with gold nanoparticle films: the influence of substrate on the luminescent properties

International Nuclear Information System (INIS)

Guidelli, Eder José; Baffa, Oswaldo; Ramos, Ana Paula

2016-01-01

Gold nanoparticle (AuNP) films were sputtered over glass and aluminum substrates to enhance optically stimulated luminescence (OSL), a luminescent technique employed for radiation detection, from x-ray irradiated NaCl nanocrystals. The AuNP films deposited over glass led to enhanced-OSL emission, whereas the AuNP films deposited on aluminum substrates quenched the OSL emission. The enhanced-OSL intensity is proportional to the optical density of the film's plasmon resonance band at the stimulation wavelength. For the case of the AuNP/aluminum films, the luminescence quenching diminishes, and OSL intensity partially recovers upon increasing the distance between the AuNPs and the aluminum substrates, and between the luminescent nanocrystals and the AuNP films. These results suggest that plasmonic interactions between the emitter nanocrystals, the localized surface plasmons (LSP) of the AuNPs, and the substrate are responsible for the OSL enhancement and quenching. In this sense, the substrate dictates whether LSP relaxation occurs by radiative or non-radiative transisitions, leading to enhanced or quenched OSL, respectively. Therefore, besides showing that AuNP films can enhance and/or tune the sensitivity of luminescent radiation detectors, and demonstrating OSL as a new technique to investigate mechanisms of plasmon-enhanced luminescence, these results bring insights on how substrates strongly modify the optical properties of AuNP films. (paper)

Luminescence properties of Yb:Nd:Tm:KY{sub 3}F{sub 10} nanophosphor and thermal treatment effects

Energy Technology Data Exchange (ETDEWEB)

Gomes, Laércio, E-mail: lgomes@ipen.br [Centro de Lasers e Aplicações, Instituto de Pesquisas Energéticas e Nucleares, IPEN-CNEN/SP, Butantã, P.O. Box 11049, São Paulo, SP o5422-970 (Brazil); Linhares, Horácio Marconi da Silva M.D. [Centro de Lasers e Aplicações, Instituto de Pesquisas Energéticas e Nucleares, IPEN-CNEN/SP, Butantã, P.O. Box 11049, São Paulo, SP o5422-970 (Brazil); Ichikawa, Rodrigo Uchida; Martinez, Luis Gallego [Departamento de Ciências dos Materiais, Instituto de Pesquisas Energéticas e Nucleares (Brazil); Ranieri, Izilda Marcia [Centro de Lasers e Aplicações, Instituto de Pesquisas Energéticas e Nucleares, IPEN-CNEN/SP, Butantã, P.O. Box 11049, São Paulo, SP o5422-970 (Brazil)

2015-01-15

In this work, we present the spectroscopic properties of KY{sub 3}F{sub 10} (KY3F) nanocrystals activated with thulium and codoped with ytterbium and neodymium ions. The most important processes that lead to the thulium upconversion emissions in the blue region were identified. A time-resolved luminescence spectroscopy technique was employed to measure the luminescence decays and to determine the most important mechanisms involved in the upconversion process that populates {sup 1}G{sub 4} (Tm{sup 3+}) excited states. Analysis of the energy-transfer processes dynamics using selective pulsed-laser excitations in Yb:Nd:Tm, Nd:KY3F nanocrystals shows that the direct energy transfer from Nd{sup 3+} to Tm{sup 3+} ions is the mechanism responsible for the 78% of the blue upconversion luminescence in the Yb:Nd:Tm:KY3F when compared with the Yb:Nd:Tm:KY3F bulk crystal for an laser excitation at 802 nm. An investigation of the {sup 1}G{sub 4} level luminescence kinetic of Tm{sup 3+} in Yb/Nd/Tm system revealed that the luminescence efficiency ({sup 1}G{sub 4}) starts with a very low value (0.38%) for the synthesized nanocrystal (as grown) and strongly increases to 97% after thermal treatment at 550 °C for 6 h under argon flow. As a consequence of the thermal treatment at T=550 °C, the contributions of the (Nd×Tm) (Up{sub 1}) and (Nd×Yb×Tm) (Up{sub 2}) upconversion processes to the {sup 1}G{sub 4} luminescence are 33% (Up{sub 1}) and 67% for Up{sub 2}. Up{sub 2} process represented by Nd{sup 3+} ({sup 4}F{sub 3/2})→Yb{sup 3+} ({sup 2}F{sub 7/2}) followed by Yb{sup 3+} ({sup 2}F{sub 5/2})→Tm ({sup 3}H{sub 4})→Tm{sup 3+} ({sup 1}G{sub 4}) was previously reported as the main mechanism to produce the blue luminescence in Yb:Nd:Tm:YLiF{sub 4} and KY{sub 3}F{sub 10} bulk crystals. Results of X-ray diffraction analysis of nanopowder using the Rietveld method reveled that crystallite sizes remain unchanged (12–14 nm) after thermal treatments with T≤400 °C, while the

Ligand-assisted fabrication, structure, and luminescence properties of Fe:ZnSe quantum dots

International Nuclear Information System (INIS)

Xie, Ruishi; Zhang, Xingquan; Liu, Haifeng

2014-01-01

Highlights: • A green route is developed for synthesis of water-soluble and fluorescent Fe:ZnSe quantum dots. • Tunable luminescence intensity can be realized with different ligand-to-Zn molar ratios. • The obtained quantum dots are in the so-called “quantum confinement regime”. -- Abstract: Here, we report a synthetic route for highly emissive Fe:ZnSe quantum dots in aqueous media using the mercaptoacetic acid ligand as stabilizing agent. The structural, morphological, componential, and optical properties of the resulting quantum dots were explored by the X-ray diffraction, transmission electron microscopy, energy-dispersive X-ray spectroscopy, inductively coupled plasma mass spectrometry, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, photoluminescence and UV–visible absorption spectroscopies. The average crystallite size was calculated to be about ca., 4.0 nm using the Scherrer equation, which correlates well with the value obtained from the transmission electron microscopy analysis. The obtained water-soluble Fe:ZnSe quantum dots in the so-called “quantum confinement regime” are spherical shaped, possess the cubic sphalerite crystal structure, and exhibit tunable luminescence properties. The presence of mercaptoacetic acid on the surface of Fe:ZnSe quantum dots was confirmed by the Fourier transform infrared spectroscopy measurements. As the ligand/Zn molar ratio increases from 1.3 to 2.8, there is little shift in the absorption peak of the Fe:ZnSe sample, indicating that the particle size of the obtained quantum dots is not changed during the synthetic process. The photoluminescence quantum yield of the as-prepared water-soluble Fe:ZnSe quantum dots can be up to 39%. The molar ratio of ligand-to-Zn plays a crucial role in determining the final luminescence properties of the resulting quantum dots, and the maximum PL intensity appears as the ligand-to-Zn molar ratio is 2.2. In addition, the underlying mechanism for

Ligand-assisted fabrication, structure, and luminescence properties of Fe:ZnSe quantum dots

Energy Technology Data Exchange (ETDEWEB)

Xie, Ruishi, E-mail: rxie@foxmail.com; Zhang, Xingquan; Liu, Haifeng

2014-03-15

Highlights: • A green route is developed for synthesis of water-soluble and fluorescent Fe:ZnSe quantum dots. • Tunable luminescence intensity can be realized with different ligand-to-Zn molar ratios. • The obtained quantum dots are in the so-called “quantum confinement regime”. -- Abstract: Here, we report a synthetic route for highly emissive Fe:ZnSe quantum dots in aqueous media using the mercaptoacetic acid ligand as stabilizing agent. The structural, morphological, componential, and optical properties of the resulting quantum dots were explored by the X-ray diffraction, transmission electron microscopy, energy-dispersive X-ray spectroscopy, inductively coupled plasma mass spectrometry, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, photoluminescence and UV–visible absorption spectroscopies. The average crystallite size was calculated to be about ca., 4.0 nm using the Scherrer equation, which correlates well with the value obtained from the transmission electron microscopy analysis. The obtained water-soluble Fe:ZnSe quantum dots in the so-called “quantum confinement regime” are spherical shaped, possess the cubic sphalerite crystal structure, and exhibit tunable luminescence properties. The presence of mercaptoacetic acid on the surface of Fe:ZnSe quantum dots was confirmed by the Fourier transform infrared spectroscopy measurements. As the ligand/Zn molar ratio increases from 1.3 to 2.8, there is little shift in the absorption peak of the Fe:ZnSe sample, indicating that the particle size of the obtained quantum dots is not changed during the synthetic process. The photoluminescence quantum yield of the as-prepared water-soluble Fe:ZnSe quantum dots can be up to 39%. The molar ratio of ligand-to-Zn plays a crucial role in determining the final luminescence properties of the resulting quantum dots, and the maximum PL intensity appears as the ligand-to-Zn molar ratio is 2.2. In addition, the underlying mechanism for

Luminescence properties of red-emitting M2Si5N8:Eu2+ (M = Ca, Sr, Ba) LED conversion phosphors

NARCIS (Netherlands)

Li, Y.Q.; Steen, van J.E.J.; Krevel, van J.W.H.; Botty, G.; Delsing, A.C.A.; DiSalvo, F.J.; With, de G.; Hintzen, H.T.J.M.

2006-01-01

The influence of the type of the alkaline-earth ion and the Eu2+ concentration on the luminescence properties of Eu2+-doped M2Si5N8 (M = Ca, Sr, Ba) has been investigated. XRD analysis shows that Eu2+-doped Ca2Si5N8 forms a limited solid solution with a maximum solubility of about 7 mol% having a

Optical and luminescence properties of zinc oxide (Review)

Science.gov (United States)

Rodnyi, P. A.; Khodyuk, I. V.

2011-11-01

We generalize and systematize basic experimental data on optical and luminescence properties of ZnO single crystals, thin films, powders, ceramics, and nanocrystals. We consider and study mechanisms by which two main emission bands occur, a short-wavelength band near the fundamental absorption edge and a broad long-wavelength band, the maximum of which usually lies in the green spectral range. We determine a relationship between the two luminescence bands and study in detail the possibility of controlling the characteristics of ZnO by varying the maximum position of the short-wavelength band. We show that the optical and luminescence characteristics of ZnO largely depend on the choice of the corresponding impurity and the parameters of the synthesis and subsequent treatment of the sample. Prospects for using zinc oxide as a scintillator material are discussed. Additionally, we consider experimental results that are of principal interest for practice.

Local symmetric distortion boosted photon up-conversion and thermometric sensitivity in lanthanum oxide nanospheres.

Science.gov (United States)

Suo, Hao; Zhao, Xiaoqi; Zhang, Zhiyu; Shi, Rui; Wu, Yanfang; Xiang, Jinmeng; Guo, Chongfeng

2018-05-17

It is essential to simultaneously boost the luminescence intensity and thermometric sensitivity of up-converted optical thermometers towards potential biomedical sensing applications. Herein, the effects of local site symmetry on the up-conversion (UC) emission and thermal sensing ability in trigonal-phased La2O3:Er3+/Yb3+ nanospheres were qualitatively explored using cubic-phased Lu2O3 and Y2O3 with a similar shape and phonon energy as contrasts. Under 980 nm light excitation, much stronger UC emissions were detected in La2O3 samples than that in cubic Lu2O3 and Y2O3 samples, and the possible mechanisms were elaborately proposed using Eu3+ as a luminescent probe. Thermo-responsive emission intensity from 2H11/2/4S3/2 levels was monitored to evaluate the absolute sensitivity of three samples, which strongly depends on the dopant-induced local site symmetric distortions according to the Judd-Ofelt theory. The potentiality of La2O3:Er3+/Yb3+ for sub-tissue thermometry was also validated by ex vivo experiments. Results open a promising avenue for realizing highly sensitive thermometry with a large signal-to-noise ratio in sub-tissues via finely tailoring the local site symmetry.

Luminescence properties of Si-containing porous matrix–PbS nanoparticle systems

International Nuclear Information System (INIS)

Tarasov, S. A.; Aleksandrova, O. A.; Lamkin, I. A.; Maksimov, A. I.; Maraeva, E. V.; Mikhailov, I. I.; Moshnikov, V. A.; Musikhin, S. F.; Nalimova, S. S.; Permyakov, N. V.; Spivak, Yu. M.; Travkin, P. G.

2015-01-01

The luminescence properties of systems that contain lead-sulfide nanoparticles deposited onto substrates fabricated from porous silicon, oxidized porous silicon, and porous (tin-oxide)–(silicon-oxide) layers are studied. It is shown that the structure and composition of the matrix induce a strong effect on the luminescence spectra of colloidal quantum dots, defining their emission wavelength

Luminescence Properties of Self-Aggregating TbIII-DOTA-Functionalized Calix[4]arenes

Science.gov (United States)

Mayer, Florian; Tiruvadi Krishnan, Sriram; Schühle, Daniel T.; Eliseeva, Svetlana V.; Petoud, Stéphane; Tóth, Éva; Djanashvili, Kristina

2018-01-01

Self-aggregating calix[4]arenes carrying four DOTA ligands on the upper rim for stable complexation of paramagnetic GdIII-ions have already been proposed as MRI probes. In this work, we investigate the luminescence properties of TbIII-DOTA-calix[4]arene-4OPr containing four propyl-groups and compare them with those of the analogue substituted with a phthalimide chromophore (TbIII-DOTA-calix[4]arene-3OPr-OPhth). We show that, given its four aromatic rings, the calix[4]arene core acts as an effective sensitizer of Tb-centered luminescence. Substituents on the lower rim can modulate the aggregation behavior, which in turn determines the luminescence properties of the compounds. In solid state, the quantum yield of the phthalimide derivative is almost three times as high as that of the propyl-functionalized analogue demonstrating a beneficial role of the chromophore on Tb-luminescence. In solution, however, the effect of the phthalimide group vanishes, which we attribute to the large distance between the chromophore and the lanthanide, situated on the opposite rims of the calix[4]arene. Both quantum yields and luminescence lifetimes show clear concentration dependence in solution, related to the strong impact of aggregation on the luminescence behaviour. We also evidence the variability in the values of the critical micelle concentration depending on the experimental technique. Such luminescent calix[4]arene platforms accommodating stable lanthanide complexes can be considered valuable building blocks for the design of dual MR/optical imaging probes.

Nanoscale luminescent lanthanide-based metal–organic frameworks: properties, synthesis, and applications

Energy Technology Data Exchange (ETDEWEB)

Hu, Dongqin; Song, Yonghai; Wang, Li, E-mail: lwanggroup@aliyun.com [Jiangxi Normal University, Key Laboratory of Functional Small Organic Molecule, Ministry of Education, Key Laboratory of Chemical Biology, Jiangxi Province, College of Chemistry and Chemical Engineering (China)

2015-07-15

Nanoscale luminescent lanthanide-based metal–organic frameworks (NLLn-MOFs) possess superior optical and physical properties such as higher luminescent lifetime, quantum yield, high stability, high surface area, high agent loading, and intrinsic biodegradability, and therefore are regarded as a novel generation of luminescent material compared with bulk lanthanide-based metal–organic frameworks (Ln-MOFs). Traditional luminescent Ln-MOFs have been well studied; however, NLLn-MOFs taking the advantages of nanomaterials have attracted extensive investigations for applications in optical imaging in living cells, light-harvesting, and sensing. In this review, we provide a survey of the latest progresses made in developing NLLn-MOFs, which contains the fundamental optical features, synthesis, and their potential applications. Finally, the future prospects and challenges of the rapidly growing field are summarized.

Luminescence properties of Y3Al5O12:Ce nanoceramics

International Nuclear Information System (INIS)

Zorenko, Yu.; Voznyak, T.; Gorbenko, V.; Zych, E.; Nizankovski, S.; Dan'ko, A.; Puzikov, V.

2011-01-01

Comparative analysis of the luminescent properties of Y 3 Al 5 O 12 :Ce (YAG:Ce) transparent optical ceramics (OS) with those of single crystal (SC) and single crystalline film (SCF) analogues has been performed under excitation by pulsed synchrotron radiation in the fundamental absorption range of YAG host. It has been shown that the properties of YAG:Ce OC are closer to the properties of the SCF counterpart, where Y Al antisite defects are completely absent, rather than to the properties of SC of this garnet with large concentration of Y Al antisite defects. At the same time, the luminescence spectra of YAG:Ce OC show weak emission bands in the 200-470 nm range related to Y Al antisite defects and charged oxygen vacancies (F + and F centers). YAG:Ce OS also possesses significantly larger contribution of slow components in the Ce 3+ luminescence decay under high-energy excitation in comparison with SC and SCF of this garnet due to the involvement of antisite defects, charged oxygen vacancies as well as boundaries of grains in the energy transfer processes from the host to the Ce 3+ ions.

Handbook of luminescent semiconductor materials

CERN Document Server

Bergman, Leah

2011-01-01

Photoluminescence spectroscopy is an important approach for examining the optical interactions in semiconductors and optical devices with the goal of gaining insight into material properties. With contributions from researchers at the forefront of this field, Handbook of Luminescent Semiconductor Materials explores the use of this technique to study semiconductor materials in a variety of applications, including solid-state lighting, solar energy conversion, optical devices, and biological imaging. After introducing basic semiconductor theory and photoluminescence principles, the book focuses

Investigation on the effect of Tb(dbm)3phen on the luminescent properties of Eu(dbm)3phen-containing mesoporous silica nanoparticles

International Nuclear Information System (INIS)

Moretti, E.; Bellotto, L.; Basile, M.; Malba, C.; Enrichi, F.; Benedetti, A.; Polizzi, S.

2013-01-01

Eu(dbm) 3 phen and Tb(dbm) 3 phen complexes (tris(dibenzoylmethane) mono(1,10-phenantroline) Ln(III)) were impregnated in ordered mesoporous silica nanoparticles (MSNs) with an average size of 50–70 nm and a pore diameter centred at 2.8 nm, with the aim of increasing the luminescence by avoiding concentration quenching and having mainly in mind the application as down-shifter for multi-crystalline solar cells. The morphological, structural, textural and luminescent properties of the synthesized samples were characterized by N 2 adsorption–desorption, X-ray diffraction (XRD), transmission electron microscopy (TEM), UV–visible spectroscopy and photoluminescence measurements. It is demonstrated that inclusion in the MSNs allows one to use much higher loadings (23 wt%) of the Eu-complex than in other matrices, and that co-doping with Tb(dbm) 3 phen improves luminescence for samples with Eu(dbm) 3 phen content lower than about 10 wt%. Results are interpreted by using a simple sphere of action model adapted to the case of a pore-limited system. - Graphical abstract: Sensitization of the antenna effect (down-conversion of UV radiation to red light) by the presence of Tb(dbm) 3 phen in the cavities of mesoporous silica nanoparticles containing Eu(dbm) 3 phen. - Highlights: • Detailed study of Eu(dbm) 3 phen-doped mesoporous silica nanoparticles luminescence. • Inclusion of up to 23 wt% of Eu(dbm) 3 phen without concentration quenching. • Detailed study of the role of the Tb(dbm) 3 phen co-dopant. • Co-doping effective for Eu 3+ (dbm) 3 phen loadings lower than about 10 wt%

Luminescence properties of KCl:Ag{sup -} crystals excited near the fundamental absorption edge

Energy Technology Data Exchange (ETDEWEB)

Kawai, Taketoshi, E-mail: buri@p.s.osakafu-u.ac.jp [Department of Physical Science, Graduate School of Science, Osaka Prefecture University, Gakuen-cho 1-1, Naka-ku, Sakai, Osaka 599-8531 (Japan); Hirai, Takeshi [Department of Physical Science, Faculty of Science and Engineering, Ritsumeikan University, Noji Higashi 1-1-1, Kusatsu, Shiga 525-8577 (Japan)

2012-02-15

Luminescence properties of KCl single crystals doped with Ag{sup -} centers have been investigated under various excitation energies around the fundamental absorption edge at low temperatures. Under the excitation at 6.89 eV, which is lower than the intrinsic exciton energy by 0.87 eV, the A Prime luminescence band due to the intraionic transition in the Ag{sup -} ion is dominantly observed at 2.91 eV. On the other hand, the excitation at 6.66 eV induces a broad luminescence band at 2.60 eV in addition to the A Prime luminescence band. From the comparison with the localized excitons in KCl:I crystals, the 2.60 eV luminescence band is attributed to the two-center type localized exciton related with the Ag{sup -} ion. The adiabatic potential energy surfaces of the excited states in the Ag{sup -} center and the localized exciton in KCl:Ag{sup -} are discussed. - Highlights: Black-Right-Pointing-Pointer We study the luminescence properties of KCl single crystals doped with Ag{sup -} ions. Black-Right-Pointing-Pointer The excitation around the absorption edge induces a broad luminescence at 2.60 eV. Black-Right-Pointing-Pointer The 2.60 eV luminescence is attributed to the exciton localized at the Ag{sup -} ion. Black-Right-Pointing-Pointer The localized exciton has the two-center type configuration of the relaxed exciton.

Luminescence properties of Ce3+ doped gadolinium-calcium-silicaborate glass scintillator

International Nuclear Information System (INIS)

Park, J.M.; Ha, D.H.; Kaewjeang, S.; Maghanemi, U.; Kothan, S.; Kaewkhao, J.; Kim, H.J.

2016-01-01

In this work, the Ce 3+ doped gadolinium-calcium-silicaborate glass scintillators of the composition ratio 25Gd 2 O 3 :10CaO:10SiO 2 :(55−x)B 2 O 3 :xCeF 3 , have been fabricated by using the melt-quenching technique. The doping concentration of the Ce 3+ was varied from 0.05 mol% to 2.5 mol%. The 4f-5d transition of the Ce 3+ allowed scintillation with a fast decay time. The absorption spectrum, X-ray induced emission spectrum, photo luminescence spectrum, laser luminescence spectrum and decay time of the scintillators were measured for studying the luminescence properties. From the X-ray induced emission spectrum result, we checked the trend between doping concentration and light yield. The laser induced luminescence spectrum was measured while changing the temperature from 300 K to 10 K. We also measured the decay time by using the laser excitation of the 0.15 mol% Ce 3+ doped glass scintillator. - Highlights: • Ce 3+ doped gadolinium-calcium-silicaborate glass scintillators were developed. • Glass is easily fabricated with large sizes and various doping materials. • The luminescence properties are studied by using various radiation sources. • The light yield and decay time were measured at low temperature. • One decay time component is found.

Luminescence Properties of Self-Aggregating TbIII-DOTA-Functionalized Calix[4]arenes

Directory of Open Access Journals (Sweden)

Florian Mayer

2018-01-01

Full Text Available Self-aggregating calix[4]arenes carrying four DOTA ligands on the upper rim for stable complexation of paramagnetic GdIII-ions have already been proposed as MRI probes. In this work, we investigate the luminescence properties of TbIII-DOTA-calix[4]arene-4OPr containing four propyl-groups and compare them with those of the analog substituted with a phthalimide chromophore (TbIII-DOTA-calix[4]arene-3OPr-OPhth. We show that, given its four aromatic rings, the calix[4]arene core acts as an effective sensitizer of Tb-centered luminescence. Substituents on the lower rim can modulate the aggregation behavior, which in turn determines the luminescence properties of the compounds. In solid state, the quantum yield of the phthalimide derivative is almost three times as high as that of the propyl-functionalized analog demonstrating a beneficial role of the chromophore on Tb-luminescence. In solution, however, the effect of the phthalimide group vanishes, which we attribute to the large distance between the chromophore and the lanthanide, situated on the opposite rims of the calix[4]arene. Both quantum yields and luminescence lifetimes show clear concentration dependence in solution, related to the strong impact of aggregation on the luminescence behavior. We also evidence the variability in the values of the critical micelle concentration depending on the experimental technique. Such luminescent calix[4]arene platforms accommodating stable lanthanide complexes can be considered valuable building blocks for the design of dual MR/optical imaging probes.

Luminescent properties of Al2O3: Tb powders

International Nuclear Information System (INIS)

Esparza G, A.E.; Garcia, M.; Falcony, C.; Azorin N, J.

2000-01-01

In this work the photo luminescent and cathode luminescent characteristics of aluminium oxide (Al 2 O 3 ) powders impurified with terbium (Tb) were studied for their use in dosimetry. The optical, structural, morphological characteristics of the powders as function of variation in the impurity concentration and the annealing temperature will be presented. As regards the optical properties of powders (photoluminescence and cathode luminescence) it was observed a characteristic emission associated with radiative transitions between electron energy levels of terbium, the spectra associated with this emission consists of several peaks associated with such transitions. In the structural and morphological characterization (X-ray diffraction and scanning electron microscopy) it was appreciated that in accordance the annealing temperature of powders is augmented it is evident the apparition of certain crystalline phases. The results show that this is a promissory material for radiation dosimetry. (Author)

Spectral conversion for thin film solar cells and luminescent solar concentrators

NARCIS (Netherlands)

Sark, van W.G.J.H.M.; Wild, de J.; Krumer, Z.; Mello Donegá, de C.; Schropp, R.E.I.; Nozik, A.J.; Beard, M.C.; Conibeer, G.

2014-01-01

Full spectrum absorption combined with effective generation and collection of charge carriers is a prerequisite for attaining high efficiency solar cells. Two examples of spectral conversion are treated in this chapter, i.e., up-conversion and down-shifting. Up-conversion is applied to thin film

Assembly and luminescence properties of lanthanide-polyoxometalates/polyethyleneimine/SiO{sub 2} particles with core–shell structure

Energy Technology Data Exchange (ETDEWEB)

Wang, Jun, E-mail: junwang924@yahoo.com.cn; Fan, Shaohua; Zhao, Weiqian; Zhang, Hongyan

2013-01-01

In this paper, two lanthanide-polyoxometalate (LnW{sub 10}) complexes were bonded on the surface of the polyethyleneimine (PEI)-modified silica nanoparticles with different sizes, resulting in the formation of LnW{sub 10}/PEI/SiO{sub 2} particles. The hybrid core–shell particles were characterized by infrared, luminescent spectra, scanning electronic microscope, and transmission electronic microscope. The particles obtained exhibit the fine spherical core–shell structure and the excellent luminescence properties. The luminescence spectra studies revealed that the formation of LnW{sub 10}/PEI/SiO{sub 2} particles and the size of particle have an influence on the luminescence properties of lanthanide ions. - Highlights: ► SiO{sub 2}/polyethyleneimine (PEI) shows the chemisorption for Ln-polyoxometalates (LnW{sub 10}). ► The core-shell LnW{sub 10}/PEI/SiO{sub 2} nanoparticles with different sizes were fabricated. ► The hybrid particles exhibit the excellent luminescence properties. ► The sizes of particles affect the luminescence properties of lanthanide ions.

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.

Synthesis, characterization and properties of novel amide derivatives based open-chain crown ether and their Tb (III) complexes

International Nuclear Information System (INIS)

Liu, Yanhong; He, Wei; Yang, Zehui; Chen, Yanwen; Wang, Xinwei; Guo, Dongcai

2015-01-01

Six amide-based open-chain crown ether and their solid complexes with terbium nitrates were synthesized. The target complexes were characterized by elemental analysis, mass spectra, EDTA titrimetric analysis, thermal analysis, molar conductivity, infrared spectra and UV–vis spectra. Luminescence properties of the ligands and the corresponding complexes in solid were studied. The results showed that the introduction of electron-donating group to the ligand enhanced the luminescence intensity of the corresponding complex, but electron-withdrawing group conversely. Meanwhile, among all complexes, the luminescence quantum yield of the complex Tb(NO 3 ) 3 Y 1 was highest up to 0.76. Electrochemical properties were also investigated, and the results showed that the introduction of electron-donating group to the ligand enhanced the highest occupied molecular orbit (HOMO) and the lowest unoccupied molecular orbit (LUMO) energy level, but electron-withdrawing group conversely. And these target complexes may possibly be useful for studying in organic light-emitting devices field. - Highlights: • Novel amide derivatives based open-chain crown ether and their Tb (III) complexes were prepared and characterized. • The target complexes presented high thermodynamic stability. • Influence of the substituent on luminescence intensity and electrochemical property were discussed

Visible luminescence peculiar to sintered silica nanoparticles: Spectral and decay properties

Energy Technology Data Exchange (ETDEWEB)

Vaccaro, L. [Dipartimento di Fisica e Chimica, Università di Palermo, Via Archirafi 36, I-90123 Palermo (Italy); Cannas, M., E-mail: marco.cannas@unipa.it [Dipartimento di Fisica e Chimica, Università di Palermo, Via Archirafi 36, I-90123 Palermo (Italy); Cangialosi, C. [Dipartimento di Fisica e Chimica, Università di Palermo, Via Archirafi 36, I-90123 Palermo (Italy); Laboratoire H. Curien, UMR CNRS 5516, Université St-Etienne, St-Etienne F-42000 (France); Spallino, L.; Gelardi, F.M. [Dipartimento di Fisica e Chimica, Università di Palermo, Via Archirafi 36, I-90123 Palermo (Italy)

2015-10-15

We report that the sintering at 1000 °C of silica nanoparticles (an average diameter of 14 nm) produces a transparent sample that exhibits a bright visible emission under UV excitation. The use of time resolved luminescence spectroscopy and a tunable laser source allows us to single out three contributions centered at 1.96 eV, 2.41 eV and 3.43 eV. The excitation spectra of these emissions evidence bell shaped bands consistent with transitions between localized defects’ states. For each emission we study the intensity and the lifetime in the temperature range from 300 K down to 10 K, thus evidencing the competition between radiative and non-radiative processes in the optical cycle of luminescent centers. The comparison with the luminescence properties of silica, both nanoparticles and bulk, points out that the observed emissions are peculiar to the sintered silica network. - Highlights: • Solid-phase sintering at 1000 °C of silica nanoparticles produces a transparent sample. • Sintered silica nanoparticles emit a bright luminescence under UV excitation. • Three emissions, centered around 2.0 V, 2.4 eV and 3.4 eV, are distinguished on the basis of the excitation and decay properties. • The observed excitation/emission bands originate from localized defect states peculiar to the sintered silica network. • The luminescence efficiency decreases with temperature due to the activation of non-radiative channels.

Mechanical, spectral, and luminescence properties of ZnS:Mn doped PDMS

Energy Technology Data Exchange (ETDEWEB)

Fontenot, Ross S. [University of Louisiana at Lafayette, Department of Physics, PO Box 44210, Lafayette, LA 70504 (United States); Allison, Stephen W., E-mail: steve.allison@emergingmeasurements.com [Emerging Measurements, Collierville, TN 38017 (United States); Lynch, Kyle J, E-mail: kjlynch@memphis.edu [Department of Physics, University of Memphis, Memphis, TN 38152 (United States); Hollerman, William A. [University of Louisiana at Lafayette, Department of Physics, PO Box 44210, Lafayette, LA 70504 (United States); Sabri, Firouzeh, E-mail: fsabri@memphis.edu [Department of Physics, University of Memphis, Memphis, TN 38152 (United States)

2016-02-15

Zinc sulfide doped with manganese (ZnS:Mn) is one of the brightest triboluminescent materials known and has been studied for a variety of applications. The powder form of this material restricts its safe handling and utilization, which limits the range of applications that can take advantage of its unique properties. In this study, the tribo- and photo-luminescent properties as well as the mechanical properties of ZnS:Mn encapsulated in an inert and optically transparent elastomer – Sylgard 184, have been investigated and fully characterized. ZnS:Mn particles of 8.5 µm diameter were incorporated into the Sylgard 184 polymer matrix prior to the curing stage with increasing amounts targeting a final (mass) concentration of 5%, 15%, and 50%. Additionally, the effect of the ZnS:Mn particles on the overall surface properties of the encapsulating elastomer was investigated and reported here. It was observed that the triboluminescent emission from impact scales with phosphor concentration and was not affected by the encapsulating medium. - Highlights: • Polymer encapsulation effects on the luminescent properties of ZnS:Mn was investigated. • Sylgard 184 encapsulated with ZnS:Mn (5, 15, 50 wt%) were characterized. • The triboluminescent emission from impact, scales with phosphor concentration. • Effect of the elastomeric medium on luminescent properties of ZnS:Mn was determined. • The work presented here demonstrates the feasibility of ZnS:Mn-based flexible sensors.

Influence of Nanosized Silicon Oxide on the Luminescent Properties of ZnO Nanoparticles

Directory of Open Access Journals (Sweden)

Vitaliy Shvalagin

2016-01-01

Full Text Available For practical use of nanosized zinc oxide as the phosphor its luminescence quantum yields should be maximized. The aim of this work was to enhance luminescent properties of ZnO nanoparticles and obtain high-luminescent ZnO/SiO2 composites using simpler approaches to colloidal synthesis. The luminescence intensity of zinc oxide nanoparticles was increased about 3 times by addition of silica nanocrystals to the source solutions during the synthesis of ZnO nanoparticles. Then the quantum yield of luminescence of the obtained ZnO/SiO2 composites is more than 30%. Such an impact of silica is suggested to be caused by the distribution of ZnO nanocrystals on the surface of silica, which reduces the probability of separation of photogenerated charges between the zinc oxide nanoparticles of different sizes, and as a consequence, there is a significant increase of the luminescence intensity of ZnO nanoparticles. This way of increasing nano-ZnO luminescence intensity facilitates its use in a variety of devices, including optical ultraviolet and visible screens, luminescent markers, antibacterial coatings, luminescent solar concentrators, luminescent inks for security printing, and food packaging with abilities of informing consumers about the quality and safety of the packaged product.

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)

Study of the luminescence properties of a natural amazonite

Energy Technology Data Exchange (ETDEWEB)

Correcher, V., E-mail: v.correcher@ciemat.es [CIEMAT, Av. Complutense 22, Madrid 28040 (Spain); Garcia-Guinea, J. [Museo Nacional de Ciencias Naturales, CSIC, C/Jose Gutierrez Abascal 2, Madrid 28006 (Spain)

2011-09-15

Most gemstones, being natural materials (silicates, carbonates, phosphates, etc.), exhibit luminescence emission. This property could be potentially employed for personal dosimetry in the case of radiation accident or radiological terrorism where conventional monitoring has not been established. We, herein, report on the thermoluminescence (TL), radioluminescence (RL) and infra-red stimulated luminescence (IRSL) response of a well-characterised natural amazonite (KAlSi{sub 3}O{sub 8}) that, due to its bright blue-green colour when polished, is used as a gemstone. The luminescence emission wavelengths, intensities and thermal kinetics of the amazonite luminescence curves reveal that the ultraviolet band measured on amazonite aliquots is similar to other common K-rich feldspars. On this basis, one can conclude (i) association between twinning and the UV-blue TL emission can be related to structural defects located in the twin-domain boundaries where ionic alkali-self-diffusion, irreversible water losses and irreversible dehydroxylation processes can be involved. (ii) Amazonite exhibits a complex structure with several planar defects (twinning and exsolution interphases which can hold hydroxyl groups, water molecules, etc.) and point defects (impurities, Na, Pb, Mn, etc.) that can act as luminescence centres, and in fact, green and red emissions are respectively associated with the presence of Mn and Fe impurities. Finally, (iv) the thermal stability tests performed on the TL emission of the amazonite confirm a continuum in the trap distribution, i.e. progressive changes in the glow curve shape, intensity and temperature position of the maximum peak.

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.

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

Benefits of Silica Core-Shell Structures on the Temperature Sensing Properties of Er,Yb:GdVO4 Up-Conversion Nanoparticles.

Science.gov (United States)

Savchuk, Oleksandr A; Carvajal, Joan J; Cascales, C; Aguiló, M; Díaz, F

2016-03-23

We studied the temperature-dependent luminescence of GdVO4 nanoparticles co-doped with Er(3+) (1 mol %) and Yb(3+) (20 mol %) and determined their thermal sensing properties through the fluorescence intensity ratio (FIR) technique. We also analyzed how a silica coating, in a core-shell structure, affects the temperature sensing properties of this material. Spectra were recorded in the range of biological temperatures (298-343 K). The absolute sensitivity for temperature determination calculated for the core-shell nanoparticles is double the one calculated for bare nanoparticles, achieving a thermal resolution of 0.4 K. Moreover, silica-coated nanoparticles show good dispersibility in different solvents, such as water, DMSO, and methanol. Also, they show good luminescence stability without interactions with solvent molecules. Furthermore, we also observed that the silica coating shell prevents progressive heating of the nanoparticles during prolonged excitation periods with the 980 nm laser, preventing effects on their thermometric applications.

Influence of Nano sized Silicon Oxide on the Luminescent Properties of Zn O Nanoparticles

International Nuclear Information System (INIS)

Shvalagin, V.; Grodziuk, G.; Kurmach, M.; Granchak, V.; Sarapulova, O.; Sherstiuk, V.

2016-01-01

For practical use of nano sized zinc oxide as the phosphor its luminescence quantum yields should be maximized. The aim of this work was to enhance luminescent properties of Zn O nanoparticles and obtain high-luminescent Zn O/SiO 2 composites using simpler approaches to colloidal synthesis. The luminescence intensity of zinc oxide nanoparticles was increased about 3 times by addition of silica nano crystals to the source solutions during the synthesis of Zn O nanoparticles. Then the quantum yield of luminescence of the obtained Zn O/SiO 2 composites is more than 30%. Such an impact of silica is suggested to be caused by the distribution of Zn O nano crystals on the surface of silica, which reduces the probability of separation of photo generated charges between the zinc oxide nanoparticles of different sizes, and as a consequence, there is a significant increase of the luminescence intensity of Zn O nanoparticles. This way of increasing nano-Zn O luminescence intensity facilitates its use in a variety of devices, including optical ultraviolet and visible screens, luminescent markers, antibacterial coatings, luminescent solar concentrators, luminescent inks for security printing, and food packaging with abilities of informing consumers about the quality and safety of the packaged product.

Luminescent chiral ionic Ir(III) complexes: Synthesis and photophysical properties

Energy Technology Data Exchange (ETDEWEB)

Ricciardi, Loredana, E-mail: loredana.ricciardi@unical.it [CNR NANOTEC-Istituto di Nanotecnologia U.O.S. Cosenza, 87036 Arcavacata di Rende (CS) (Italy); La Deda, Massimo; Ionescu, Andreea; Godbert, Nicolas; Aiello, Iolinda; Ghedini, Mauro [MAT-INLAB (Laboratorio di Materiali Molecolari Inorganici), LASCAMM and CR INSTM, Unità INSTM della Calabria, Dipartimento di Chimica e Tecnologie Chimiche, Università della Calabria, 87036 Arcavacata di Rende (CS) (Italy); Fusè, Marco, E-mail: marco.fuse@unimi.it [Dipartimento di Scienze Farmaceutiche, Università di Milano, Via Golgi 19, 20133 Milano (Italy); Rimoldi, Isabella; Cesarotti, Edoardo [Dipartimento di Scienze Farmaceutiche, Università di Milano, Via Golgi 19, 20133 Milano (Italy)

2016-02-15

Three homologous series of luminescent octahedral ionic Ir(III) complexes (1–12) with a dual stereogenic center of general formula {sup Δ,Λ} {sup (R,S)}[(ppy){sub 2}Ir(R-campy)]X, where ppy=2-phenylpyridine, R-campy=2-methyl-5,6,7,8-tetrahydroquinolin-8-amine (Me-campy) or 8-amino-5,6,7,8-tetrahydroquinolines (H-campy) and as counterions X{sup −}=Cl{sup −} or CH{sub 3}COO{sup −} have been synthesized and characterized. The NMR characterization of each complex highlighted the diastereoisomeric purity and the absolute configuration has been confirmed by Electronic Circular Dichroism spectroscopy. The absorption and the luminescence properties of the compounds in solution and in solid state have been investigated by UV–vis, steady-state emission and time-correlated single-photon counting spectroscopy. The obtained results from the 12 compounds highlight the difficult to correlate photophysical properties in solution to the stereochemistry, while excited states decay studies of the solid state samples indicate a correlation between photophysics and packing mode which is affected by the different stereochemistry. - Highlights: • Luminescent chiral ionic Ir(III) complexes have been synthesized and characterized. • Presence in the same structure of two stereogenic centers. • Use of camphorsulfonate as resolving anion to obtain enantiomerically pure samples. • Stereoisomers produce aggregates with different emitting properties. • Lifetimes from solid samples show the presence of AIPE.

Fabrication and characterization of dual-functional ultrafine composite fibers with phase-change energy storage and luminescence properties.

Science.gov (United States)

Xi, Peng; Zhao, Tianxiang; Xia, Lei; Shu, Dengkun; Ma, Menjiao; Cheng, Bowen

2017-01-09

Ultrafine composite fibers consisting of a thermoplastic polyurethane solid-solid phase-change material and organic lanthanide luminescent materials were prepared through a parallel electrospinning technique as an innovative type of ultrafine, dual-functional fibers containing phase-change and luminescent properties. The morphology and structure, thermal energy storage, and luminescent properties of parallel electrospun ultrafine fibers were investigated. Scanning electron microscopy (SEM) images showed that the parallel electrospun ultrafine fibers possessed the desired morphologies with smaller average fiber diameters than those of traditional mixed electrospun ultrafine fibers. Transmission electron microscopy (TEM) images revealed that the parallel electrospun ultrafine fibers were composed of two parts. Polymeric phase-change materials, which can be directly produced and spun, were used to provide temperature stability, while a mixture of polymethyl methacrylate and an organic lanthanide complex acted as the luminescent unit. Differential scanning calorimetry (DSC) and luminescence measurements indicated that the unique structure of the parallel electrospun ultrafine fibers provides the products with good thermal energy storage and luminescence properties. The fluorescence intensity and the phase-change enthalpy values of the ultrafine fibers prepared by parallel electrospinning were respectively 1.6 and 2.1 times those of ultrafine fibers prepared by mixed electrospinning.

New Sr{sub 1−x−z}R{sub x}(NH{sub 4}){sub z}F{sub 2+x−z} (R = Yb, Er) solid solution as precursor for high efficiency up-conversion luminophor and optical ceramics on the base of strontium fluoride

Energy Technology Data Exchange (ETDEWEB)

Rozhnova, Yu. A. [N.E. Bauman Moscow State Technical University, Moscow (Russian Federation); A.M. Prokhorov General Physics Institute, RAS, Moscow (Russian Federation); Kuznetsov, S.V. [A.M. Prokhorov General Physics Institute, RAS, Moscow (Russian Federation); Luginina, A.A. [All-Russian Institute for Scientific and Technical Information (VINITI), Moscow (Russian Federation); Voronov, V.V.; Ryabova, A.V.; Pominova, D.V.; Ermakov, R.P. [A.M. Prokhorov General Physics Institute, RAS, Moscow (Russian Federation); Usachev, V.A.; Kononenko, N.E. [N.E. Bauman Moscow State Technical University, Moscow (Russian Federation); Baranchikov, A.E.; Ivanov, V.K. [N.S. Kurnakov Institute of General and Inorganic Chemistry, RAS, Moscow (Russian Federation); Fedorov, P.P., E-mail: ppfedorov@yandex.ru [A.M. Prokhorov General Physics Institute, RAS, Moscow (Russian Federation)

2016-04-01

In this paper, we describe the use of self-fluorinating conditions for the thermal treatment of Sr{sub 1−x−y−z}Yb{sub x}Er{sub y}(NH{sub 4}){sub z}F{sub 2+x+y−z} precursor for the preparation of high-efficiency SrF{sub 2}:Yb:Er up-converter powders. We report actual SrF{sub 2}:Yb:Er compositions with up-conversion efficiencies exceeding 4% (pumping power 1 W/cm{sup 2} at 974 nm wavelength) and describe the synthesis of ceramics with higher than 80% transmittance at 0.42–7.0 μm. The latter ceramics can be used as a potential IR radiation visualizer. For the first time, we present an analysis of correlation between up-conversion luminescence energy yield and specimen composition for SrF{sub 2}:Yb:Er nanopowders. Taking into account the observed erbium ion up-conversion luminescence in the red part of the visible spectrum, we recommend certain SrF{sub 2}:Yb:Er compositions for practical application in photodynamic cancer therapy. - Highlights: • SrF{sub 2}:Yb/Er luminophor nanopowders were precipitated from aqueous solutions. • Precipitation of Sr{sub 1−x−y−z}Yb{sub x}Er{sub y}(NH{sub 4}){sub z}F{sub 2+x+y−z} solid solution has been proved. • Up-conversion luminescence energy yield luminophors of more than 4% were obtained. • Optical ceramics with 80% transmittance in 0.42–7.0 μm range was synthesized.

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

Photon up-conversion increases biomass yield in Chlorella vulgaris.

Science.gov (United States)

Menon, Kavya R; Jose, Steffi; Suraishkumar, Gadi K

2014-12-01

Photon up-conversion, a process whereby lower energy radiations are converted to higher energy levels via the use of appropriate phosphor systems, was employed as a novel strategy for improving microalgal growth and lipid productivity. Photon up-conversion enables the utilization of regions of the solar spectrum, beyond the typical photosynthetically active radiation, that are usually wasted or are damaging to the algae. The effects of up-conversion of red light by two distinct sets of up-conversion phosphors were studied in the model microalgae Chlorella vulgaris. Up-conversion by set 1 phosphors led to a 2.85 fold increase in biomass concentration and a 3.2 fold increase in specific growth rate of the microalgae. While up-conversion by set 2 phosphors resulted in a 30% increase in biomass and 12% increase in specific intracellular neutral lipid, while the specific growth rates were comparable to that of the control. Furthermore, up-conversion resulted in higher levels of specific intracellular reactive oxygen species in C. vulgaris. Up-conversion of red light (654 nm) was shown to improve biomass yields in C. vulgaris. In principle, up-conversion can be used to increase the utilization range of the electromagnetic spectrum for improved cultivation of photosynthetic systems such as plants, algae, and microalgae. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Luminescent properties of terbium complexes with catecholamines and their application in analysis

International Nuclear Information System (INIS)

Kravchenko, T.B.; Bel'tyukova, S.V.; Kononenko, L.I.; Poluehktov, N.S.

1982-01-01

Tb complexing with a representative of catecholamines - adrenaline - is studied using the luminescence method. It is found, that the complexing takes place in alkaline medium (pH 12.0). To prevent from compound oxidation with air oxygen and to create the necessary pH in solution sodium borohydride is used. The highest luminescence intensity is achieved when the reaction occurs in aqueous-isopropanol solutions. It is established that in the complexes formed the ratio of components is the following: Tb:adrenaline=1:3. Luminescent properties of Tb complex with adrenaline are used to determine the latter. The least detectable amount of adrenaline constitutes 0.02 μg, the determination error does not exceed 5.5% [ru

The thermoluminescence and optically stimulated luminescence properties of Cr-doped alpha alumina transparent ceramics

International Nuclear Information System (INIS)

Liu, Qiang; Yang, Qiu Hong; Zhao, Guang Gen; Lu, Shen Zhou; Zhang, Hao Jia

2013-01-01

Highlights: •Polycrystalline Cr:α-Al 2 O 3 transparent ceramics were obtained with vacuum sintering method. •The influence of different concentration of Cr 2 O 3 on the thermoluminescence and optical stimulated luminescence properties of Cr:α-Al 2 O 3 transparent ceramics was studied. •It had a main peak at 503 K of very high intensity and linear concentration dependence up to high concentration. •It showed so interesting results with high TL sensitivity and high stability of OSL signal that Cr:α-Al 2 O 3 transparent ceramics might be a promising material in TL dosimetry and replace Cr:α-Al 2 O 3 crystals. -- Abstract: Polycrystalline Cr:α-Al 2 O 3 transparent ceramics were fabricated by conventional solid-state processing under vacuum condition. The SEM microstructure photographs of Cr:α-Al 2 O 3 transparent ceramics doped with different content of Cr 2 O 3 were investigated. The absorption, emission spectra, thermoluminescence and optical stimulated luminescence of Cr:α-Al 2 O 3 transparent ceramics were comparable to those of Cr:α-Al 2 O 3 crystals. The influence of different concentration of Cr 2 O 3 on the thermoluminescence and optical stimulated luminescence properties of Cr:α-Al 2 O 3 transparent ceramics was discussed. It showed so interesting results with high TL sensitivity and high stability of OSL signal that Cr:α-Al 2 O 3 transparent ceramics might be a promising material in TL dosimetry and replace Cr:α-Al 2 O 3 crystals

The luminescence properties of the octahedral uranate group in oxides with perovskite structure, ch. 3

International Nuclear Information System (INIS)

Hair, J.Th.W. de

1976-01-01

This chapter describes how the luminescence properties of the octahedral uranate group are influenced by the chemical constitution of its environment. Especially the quenching temperature of the emission is very sensitive. It is stronger influenced by the nature of the neighbouring B cations in the [100] direction than by the A cations in the [111] direction. This variation of the quenching temperature as a function of the chemical constitution of the host lattice is discussed in terms of a configurational coordinate model. The luminescence properties of uranium-activated oxides A 2+ La 3+ B + B'O 6 are also discussed. Remarkably enough in SrLaNaWO 6 -U the luminescence originates from UO 2 2+ groups. (Auth.)

The down-conversion and up-conversion photoluminescence properties of Na0.5Bi0.5TiO3:Yb3+/Pr3+ ceramics

International Nuclear Information System (INIS)

Huang, Yinpeng; Luo, Laihui; Wang, Jia; Zuo, Qianghui; Yao, Yongjie; Li, Weiping

2015-01-01

Na 0.5 Bi 0.5−x−y Yb x Pr y TiO 3 (NBT:xYb/yPr) ceramics with different Yb and Pr contents are prepared. Both the down-conversion (DC) and up-conversion (UC) photoluminescence (PL) of the ceramics via 453 and 980 nm excitation, respectively, are investigated. The effect of Yb 3+ and Pr 3+ doping contents on the DC and UC PL is significantly different from each other. Furthermore, the UC PL of the ceramics as a function of temperatures is measured to investigate the UC process in detail. Based on energy level diagram of Pr 3+ and Yb 3+ ions and the DC and UC PL spectra, the DC and UC PL mechanisms of Pr 3+ and Yb 3+ ions are discussed. Especially, the UC PL mechanism is clarified, which is different from the previously reported literature. Also, the temperature sensing properties of the ceramics are studied based on the photoluminescence ratio technique, using the thermal coupling energy levels of Pr 3+

Down-conversion luminescence and its temperature-sensing properties from Er3+-doped sodium bismuth titanate ferroelectric thin films

Science.gov (United States)

Wang, Shanshan; Zheng, Shanshan; Zhou, Hong; Pan, Anlian; Wu, Guangheng; Liu, Jun-ming

2015-11-01

Here, we demonstrate outstanding temperature-sensing properties from Na0.5Bi0.49Er0.01TiO3 (NBT:Er) thin films. The perovskite phase for them is stable in the temperature range from 80 to 440 K. Interestingly, the Er doping enhances the ferroelectric polarization and introduces local dipolar, which are positive for temperature sensing. Pumped by a 488-nm laser, the NBT:Er thin films show strong green luminescence with two bands around 525 and 548 nm. The intensity ratio I 525/ I 548 can be used for temperature sensing, and the maximum sensitivity is about 2.3 × 10-3 K-1, higher than that from Er-doped silicon oxide. These suggest NBT:Er thin film is a promising candidate for temperature sensor.

Luminescent properties of Y3Al5−xGaxO12:Ce crystals

International Nuclear Information System (INIS)

Zorenko, Yu.; Zorenko, T.; Malinowski, P.; Sidletskiy, O.; Neicheva, S.

2014-01-01

Absorption, luminescent and scintillation properties of Ce 3+ doped Y 3 Al 5−x Ga x O 12 crystals with Ga content in the x=1–5 range were investigated in this work and compared with the properties of YAG:Ce crystals. Apart from the traditional spectral methods (absorption, cathodoluminescence and light yield measurements), the intrinsic and Ce 3+ related luminescence of Y 3 Al 5−x Ga x O 12 :Ce solid-solution were also investigated using the luminescent spectroscopy under excitation by synchrotron radiation in the 3.7–25 eV range. We show that the optical properties Y 3 Al 5−x Ga x O 12 :Ce garnets monotonically change with increasing the Ga content in the x=0–3 range due to preferable localization of Ga ions in the tetrahedral position of the garnet lattice. At the highest Ga concentration (x>3) the deviation of the optical properties of Y 3 Al 5−x Ga x O 12 :Ce garnets is observed from the respective properties of these crystals with Ga content in the x=0–3 range due to occupation by Ga ions of the octahedral position in the garnet host. - Highlights: • Different dependence of optical properties of Y 3 Al 5−x Ga x O 12 :Ce crystals on Ga content in x=0–3 and 3–5 ranges. • Elimination of the luminescence of Y Al antisite defects in Y 3 Al 5−x Ga x O 12 :Ce crystals at x>2. • Significant improvement of the scintillation properties of Y 3 Al 5−x Ga x O 12 :Ce crystals at x=2 and 3 in comparison with YAG:Ce

LUMINESCENT PROPERTIES OF SILICATE GLASSES WITH CERIUM IONS AND ANTIMONY

Directory of Open Access Journals (Sweden)

A. M. Klykova

2014-05-01

Full Text Available The paper deals with the results of an experimental study of luminescence excitation spectra and luminescence of silicate glasses containing cerium ions and antimony. The aim of this work was to study the features of the luminescence and the effect of UV irradiation and heat treatment on luminescence and the state of cerium ions and antimony in glass. We investigated glass system Na2O-ZnO-Al2O3-SiO2-NaF-NaBr with additives CeO2 and Sb2O3. Synthesis was carried out in platinum crucibles in the air at 14500C. The samples were polished glass plates with a thickness of 0.5-1 mm. UV irradiation was carried out with a mercury lamp having a wide range of radiation in the spectral range 240-390 nm. It was conducted in a Nabertherm muffle furnaces. Luminescence spectra and excitation spectra were measured using a spectrofluorimeter MPF-44A (PerkinElmer at the room temperature. Measured luminescence spectra were corrected in view of the spectral sensitivity of the photodetector for spectrofluorimeter. Adjustment of the excitation spectra for the spectral dependence of the intensity of the excitation source was not carried out. During the experiments it was found that in silicate glasses Sb3+ ions can exist in two energy states, which corresponds to a different environment with oxygen ions. Heat treatment of these glasses in an oxidizing atmosphere leads to an increase in ion concentration of Sb3+ ions with a greater amount of oxygen in the environment. In glasses containing antimony and cerium ions, ultraviolet irradiation causes a change in the valence of cerium ions and antimony, which is accompanied by luminescence quenching. Subsequent heat treatment of glass leads to the inverse processes and restore luminescence excitation spectra. The study of fluorescent properties of silicate glasses with cerium and antimony ions led to the conclusion of the practical significance of this work. Promising multifunctional materials can be created on the basis of

Spectroscopic properties of Yb3+ and Er3+ ions in heavy metal glasses

International Nuclear Information System (INIS)

Pisarski, Wojciech A.; Grobelny, Lukasz; Pisarska, Joanna; Lisiecki, Radoslaw; Ryba-Romanowski, Witold

2011-01-01

Highlights: → Heavy metal glasses doubly doped with Yb 3+ and Er 3+ were examined. → NIR luminescence at about 1530 nm and green and red up-conversion spectra were detected. → The unusual large spectral linewidth nearly close to 110 nm for 4 I 13/2 - 4 I 15/2 transition of Er 3+ ions in Yb-Er co-doped lead borate glass was obtained. → Long-lived NIR luminescence was detected in lead germanate glass. → The NIR luminescence and up-conversion phenomena strongly depend on stretching vibrations of glass host. - Abstract: Selected heavy metal glasses containing Yb 3+ and Er 3+ ions have been studied. Near-infrared luminescence spectra at 1.53 μm and up-conversion spectra of Er 3+ ions were registered under excitation of Yb 3+ ions by 975 nm diode laser line. The luminescence bands correspond to 4 I 13/2 - 4 I 15/2 (NIR), 4 S 3/2 - 4 I 15/2 (green) and 4 F 9/2 - 4 I 15/2 (red) transitions of Er 3+ , respectively. The optical transitions of rare earth ions have been examined as a function of glass host. The unusual large spectral linewidth nearly close to 110 nm for 4 I 13/2 - 4 I 15/2 transition of Er 3+ ions in Yb-Er co-doped lead borate glass was obtained, whereas long-lived NIR luminescence at 1.53 μm was detected in lead germanate glass. The NIR luminescence and up-conversion phenomena strongly depend on stretching vibrations of glass host, which was confirmed by FT-IR spectroscopy.

An estimate of spherical impactor energy transfer for mechanical frequency up-conversion energy harvester

Directory of Open Access Journals (Sweden)

L. R. Corr

2016-08-01

Full Text Available Vibration energy harvesters, which use the impact mechanical frequency up-conversion technique, utilize an impactor, which gains kinetic energy from low frequency ambient environmental vibrations, to excite high frequency systems that efficiently convert mechanical energy to electrical energy. To take full advantage of the impact mechanical frequency up-conversion technique, it is prudent to understand the energy transfer from the low frequency excitations, to the impactor, and finally to the high frequency systems. In this work, the energy transfer from a spherical impactor to a multi degree of freedom spring / mass system, due to Hertzian impact, is investigated to gain insight on how best to design impact mechanical frequency up-conversion energy harvesters. Through this academic work, it is shown that the properties of the contact (or impact area, i.e., radius of curvature and material properties, only play a minor role in energy transfer and that the equivalent mass of the target system (i.e., the spring / mass system dictates the total amount of energy transferred during the impact. The novel approach of utilizing the well-known Hertzian impact methodology to gain an understanding of impact mechanical frequency up-conversion energy harvesters has made it clear that the impactor and the high frequency energy generating systems must be designed together as one system to ensure maximum energy transfer, leading to efficient ambient vibration energy harvesters.

Polymethylmethacrylate-based luminescent solar concentrators with bottom-mounted solar cells

International Nuclear Information System (INIS)

Zhang, Yi; Sun, Song; Kang, Rui; Zhang, Jun; Zhang, Ningning; Yan, Wenhao; Xie, Wei; Ding, Jianjun; Bao, Jun; Gao, Chen

2015-01-01

Graphical abstract: - Highlights: • Bottom-mounted luminescent solar concentrators on dye-doped plates were studied. • The mechanism of transport process was proposed. • The fabricated luminescent solar concentrator achieved a gain of 1.38. • Power conversion efficiency of 5.03% was obtained with cell area coverage of 27%. • The lowest cost per watt of $1.89 was optimized with cell area coverage of 18%. - Abstract: Luminescent solar concentrators offer an attractive approach to concentrate sunlight economically without tracking, but the narrow absorption band of luminescent materials hinders their further development. This paper describes bottom-mounted luminescent solar concentrators on dye-doped polymethylmethacrylate plates that absorb not only the waveguided light but also the transmitted sunlight and partial fluorescent light in the escape cone. A series of bottom-mounted luminescent solar concentrators with size of 78 mm × 78 mm × 7 mm were fabricated and their gain and power conversion efficiency were investigated. The transport process of the waveguided light and the relationship between the bottom-mounted cells were studied to optimize the performance of the device. The bottom-mounted luminescent solar concentrator with cell area coverage of 9% displayed a cell gain of 1.38, to our best knowledge, which is the highest value for dye-doped polymethylmethacrylate plate luminescent solar concentrators. Power conversion efficiency as high as 5.03% was obtained with cell area coverage of 27%. Furthermore, the bottom-mounted luminescent solar concentrator was found to have a lowest cost per watt of $1.89 with cell area coverage of 18%. These results suggested that the fabricated bottom-mounted luminescent solar concentrator may have a potential in low-cost building integrated photovoltaic application

Phase transition and luminescence properties from vapor etched silicon

International Nuclear Information System (INIS)

Aouida, S.; Saadoun, M.; Ben Saad, K.; Bessais, B.

2006-01-01

In this work, we present a study on the structure and photoluminescence (PL) properties of a non-conventional ammonium hexafluorosilicate (NH 4 ) 2 SiF 6 (white powder) obtained from HNO 3 /HF chemical vapor etching (CVE) of silicon wafers. The CVE method leads either to the formation of luminescent Porous Silicon (PS) or SiO x /Si-containing (NH 4 ) 2 SiF 6 depending on the experimental conditions. At specific conditions (i.e., HNO 3 / HF volume ratio > 1 / 4), the CVE technique can generate instead of PS, a (NH 4 ) 2 SiF 6 phase where SiO x /Si particles are embedded. The (NH 4 ) 2 SiF 6 marketed powder is not luminescent, while that obtained from silicon vapor-etching presents a noticeable intense and stable photoluminescence (PL), which was found to have mainly two shoulders at 1.98 and 2.1 eV. Two processes have been proposed to explain this PL property. First, the visible luminescence around 1.98 eV would come from silicon nanoparticles embedded in the powder, having a distribution size that does not allow SiO x species to influence their own PL. Second, the PL shoulder around 2.1 eV would originate from small silicon nanoparticles trapped in SiO x features, leading to oxide related states that may trap electrons or excitons, depending on the silicon nanoparticle size, wherein radiative recombination occurs. The PL shoulder could become broader at low temperatures suggesting the existence of radiative recombination in SiO x related defects

Bottom-up synthesis of up-converting submicron-sized Er3+-doped LiNbO3 particles

International Nuclear Information System (INIS)

Jardiel, T.; Caballero, A.C.; Marín-Dobrincic, M.; Cantelar, E.; Cussó, F.

2012-01-01

A new and simple wet chemical synthesis method is proposed to prepare submicron-sized Erbium-doped LiNbO 3 powders. The synthesis procedure comprises the co-precipitation of lithium and erbium ions from common precursors and their subsequent reaction with niobium ethoxide. A systematic characterization by means of X-Ray Diffraction (XRD), X-ray Fluorescence (XRF), Inductively Coupled Plasma (ICP-OES), Atomic Absorption (AAS), Field Emission Scanning Electron Microscopy (FE-SEM), as well as by the examination of the luminescence properties, evidence that with this method a congruent Er 3+ -doped LiNbO 3 single phase material can be obtained without using complex and time-consuming processing steps. The synthesized powders exhibit efficient IR to VIS up-conversion emissions under 974 nm pumping. -- Highlights: ► A novel chemical route to the preparation of LiNbO 3 powders has been developed. ► This process avoids complex and time-consuming processing steps. ► A congruent Er 3+ -doped LiNbO 3 single phase material can be obtained by this way. ► The luminescence properties are the expected for this composition.

Optical and luminescence properties of hydrogenated amorphous carbon

International Nuclear Information System (INIS)

Rusli

1996-03-01

In this thesis, the optical and luminescence properties of hydrogenated amorphous carbon(a - C:H) thin films deposited using a Plasma Enhanced Chemical Vapour Deposition (PECVD) system are studied. A photoluminescence (PL) measuring system with a wavelength range of 300nm to 900nm, used for the above study, has been set up as a main part of the research. Firstly, a simple yet powerful method developed to solve for the optical constants and thickness of a - C : H deposited on Si is presented. This is followed by an investigation into the optical properties of band gap modulated a - C : H thin films superlattice structures. a - C : H films, obtained from a wide range of deposition conditions, are then characterised in terms of their optical absorption, infrared absorption, Raman scattering, fraction of sp 2 to sp 3 bondings and unpaired electron spin density. Their PL characteristics, such as the peak emission energy, spectral bandwidth, quantum efficiency, fatigue and polarisation memory are investigated in relation to their microstructure. The results, taken together with those obtained from photoconductivity study and electric field quenching of PL, are used to understand the origin of the strong PL in a - C : H. Preliminary work on a - C : H electroluminescent celbis also presented. (author)

A New Generation of Luminescent Materials Based on Low-Dimensional Perovskites

KAUST Repository

Pan, Jun

2017-06-02

Low-dimensional perovskites with high luminescence properties are promising materials for optoelectronic applications. In this article, properties of two emerging types of low-dimensional perovskites are discussed, including perovskite quantum dots CsPbX3 (X = Cl, Br or I) and zero-dimensional perovskite Cs4PbBr6. Moreover, their application for light down conversion in LCD backlighting systems and in visible light communication are also presented. With their superior optical properties, we believe that further development of these materials will potentially open more prospective applications, especially for optoelectronics devices.

Up-conversion mechanisms in Er{sup 3+} doped YbAG crystals

Energy Technology Data Exchange (ETDEWEB)

Kaczkan, Marcin; Borowska, Maja [Institute of Microelectronics and Optoelectronics PW, Warsaw (Poland); Malinowski, Michal [Institute of Microelectronics and Optoelectronics PW, Warsaw (Poland); Institute of Electronic Materials Technology, Warsaw (Poland); Lukasiewicz, Tadeusz; Kolodziejak, Katarzyna [Institute of Electronic Materials Technology, Warsaw (Poland)

2009-07-15

Up-conversion phenomena leading to the red, green and violet emissions in erbium doped ytterbium-aluminum garnet (YbAG) are investigated. Absorption and emission spectra and luminescence dynamics from various excited states of YbAG:Er{sup 3+} were registered. The low temperature absorption spectra were used to determine Stark levels energies of Er{sup 3+} ion in the investigated host. Emissions from the high lying excited states {sup 2}G{sub 9/2}, {sup 4}S{sub 3/2} and {sup 4}F{sub 9/2} of Er{sup 3+} were characterized under pulsed multi-photon IR excitation in the region of wavelength corresponding to the strong {sup 2}F{sub 7/2} {yields} {sup 2}F{sub 5/2} absorption transition of Yb{sup 3+} ions. Using the rate equations formalism the dynamics of the observed emissions were modeled. From the comparison of the measured and calculated decays the energy transfer rates between Yb{sup 3+} and Er{sup 3+} ions were evaluated. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Paleodosimetrical properties of sodium alkali feldspars and problems of luminescence dating of sediments

International Nuclear Information System (INIS)

Huett, Galina; Jaek, Ivar

1996-01-01

Emission spectra of natural alkali feldspars extracted from sediments are studied using a CCD-camera based high sensitivity spectrometer. Applying a semiconductor laser (860± 1 nm), two dominant emission bands, blue (410 nm) and orange (570 nm), are revealed in infrared optically stimulated luminescence (IROSL) spectra for the most of the sediments from Scandinavian sections. Luminescence and dosimetric al properties of the hole traps, the induced orange emission band typical of sodium alkali feldspars are studied. As a result, high light bleach ability but low stability of the dosimetric al information lit sodium alkali feldspars are established. Problems of luminescence dating of sediments based on the mixture of potassium-sodium alkali feldspars are discussed. (author)

Up-conversion luminescence application in Er3+: TiO2 thin film prepared by dip coating sol-gel route

International Nuclear Information System (INIS)

Badr, Y.; Battisha, I.K.; Salah, A.; Salem, M.A.

2008-01-01

Sol-gel derived nano-crystalline titanium dioxide films doped with 1 up to 5% Er 3+ ions were prepared by dip coating sol-gel method. The coating sol was obtained by hydrolysis of Ti(OC 4 H 9 ) 4 in ethanol/HCI solution. The FT-Raman and the X-ray diffraction (XRD) were carried out to determine the crystal structure of the prepared samples. The morphology SEM and the cross-sectional of the film were used to characterize the microstructure and the thickness of the prepared film. It is shown that relative homogeneous, crack-free and transparent film was achieved via dipping process at 500 deg C. After the excitation with laser diode at wavelength 808 nm, visible (Vis) and infrared (IR) up-conversion emissions were evidenced in the thin film samples under investigation. The up-conversion was found to depend strongly on the Er 3+ ion concentrations. The visible emission was found to be at 540, 560, 590 and 640 nm for thin film. They are attributed to intra-4f transition of Er 3+ ions and assigned to the ( 2 H 11/2 + 4 S 3/2 ) and 4 F 9/2 , which are populated through excited state absorption (ESA) for 808 nm excitation. (author)

Luminescent and scintillation properties of Bi{sup 3+} doped Y{sub 2}SiO{sub 5} and Lu{sub 2}SiO{sub 5} single crystalline films

Energy Technology Data Exchange (ETDEWEB)

Zorenko, Yu., E-mail: zorenko@ukw.edu.pl [Institute of Physics, Kazimierz Wielki University in Bydgoszcz, 85-090 Bydgoszcz (Poland); Gorbenko, V.; Zorenko, T. [Institute of Physics, Kazimierz Wielki University in Bydgoszcz, 85-090 Bydgoszcz (Poland); Laboratory for Optoelectronic Materials (LOM), Department of Electronics of Ivan Franko National University of Lviv, 79017 Lviv (Ukraine); Malinowski, P. [Institute of Physics, Kazimierz Wielki University in Bydgoszcz, 85-090 Bydgoszcz (Poland); Jary, V.; Kucerkova, R.; Beitlerova, A.; Mares, J.A.; Nikl, M. [Institute of Physics AS CR, Cukrovarnicka 10, 16253 Prague (Czech Republic); Fedorov, A. [Institute for Single Crystals NAS of Ukraine, 60 Lenin ave., 61001 Kharkiv (Ukraine)

2014-10-15

In this paper we report our follow-up research on the Bi{sup 3+} luminescence in orthosilicate compounds, focusing on absorption, luminescent and scintillation properties of YSO:Bi and LSO:Bi SCFs with the Bi concentration ranging from 0.05 to 0.18 at%. For purpose of this research, single crystalline films (SCF) of Y{sub 2}SiO{sub 5}:Bi and Lu{sub 2}SiO{sub 5}:Bi have been grown by the LPE method onto YSO and LSO substrates from the melt-solution based on Bi{sub 2}O{sub 3} flux. - Highlights: • YSO:Bi and LSO:Bi films have been grown by liquid phase epitaxy. • Bi{sup 3+} absorption and luminescence depends on Bi concentration. • Scintillation properties of YSO:Bi and LSO:Bi films have been studied.

3D Rare earth porous coordination frameworks with formamide generated in situ syntheses: Crystal structure and down- and up-conversion luminescence

Energy Technology Data Exchange (ETDEWEB)

Ma, Xue [Department of Chemistry, Capital Normal University, Beijing 100048 (China); Tian, Jing [Department of Chemistry, Capital Normal University, Beijing 100048 (China); Experiment and Teaching Resource Management Centre, Yibin University, Yibin, 644000 (China); Yang, Hong-Y.; Zhao, Kai [Department of Chemistry, Capital Normal University, Beijing 100048 (China); Li, Xia, E-mail: xiali@mail.cnu.edu.cn [Department of Chemistry, Capital Normal University, Beijing 100048 (China)

2013-05-01

The reaction of RE(NO)₃·6H₂O and formamide yielded the coordination polymers, [RE(HCOO)₄]⁻[NH₂CHNH₂]⁺ (RE=Y 1, Eu 2, Gd 3, Tb 4, Dy 5, Er 6, and Yb 7). They possess 3D porous frameworks with the 1D rhombic channels occupied by [NH₂CHNH₂]⁺ cations. Complexes 2 and 4 display the characteristic down-conversion emissions corresponding to ⁵D₀→⁷F_J (J=1–4) transitions of Eu(III) ion and ⁵D₄→⁷F_J (J=6–3) transitions of Tb(III) ion, respectively. Longer lifetime values of 2.128±0.002 ms (⁵D₀) for 2 and 2.132±0.002 ms (⁵D₄) for 4 have been observed. The up-conversion spectra of the Y:Yb,Er and Gd:Yb,Er codoped complexes exhibit three emission bands around 410 (⁴H_9/2→⁴I_15/2, blue), 518–570 (⁴S_3/2, ²H_11/2→⁴I_15/2, green), and 655 nm (⁴F_9/2→⁴I_15/2, red). - Graphical Abstract: The complexes [RE(HCOO)₄]⁻[NH₂CHNH₂]⁺ possess 3D porous frameworks. Eu(III) and Tb(III) complexes show characteristic emission of Ln(III) ions. The up-conversion emission of the Y:Yb,Er and Gd:Yb,Er codoped complexes was observed. Highlights: •The reaction of RE(NO)₃·6H₂O and formamide produced complexes [RE(HCOO)₄]⁻[NH₂CHNH₂]⁺. • The complexes possess 3D frameworks with the 1D channels occupied by [NH₂CHNH₂]⁺ cations. • Eu(III)/Tb(III) complexes display the characteristic down-conversion emission of Ln(III) ions. • The Y:Yb,Er and Gd:Yb,Er doped complexes exhibit the up-conversion emission.

Conversion of the luminescence of laser dyes in opal matrices to stimulated emission

International Nuclear Information System (INIS)

Alimov, O K; Basiev, T T; Orlovskii, Yu V; Osiko, V V; Samoilovich, M I

2008-01-01

The luminescence and laser characteristics of a synthetic opal matrix filled with organic dyes are studied upon excitation by nanosecond laser pulses. The appearance of stimulated emission in a partially ordered scattering medium is investigated. It is shown that if the luminescence spectrum of a dye (oxazine-17) is located far outside the photonic bandgap of the opal matrix, stimulated emission along a preferential direction in the (111) plane is observed when pumping exceeds a threshold even without an external optical cavity. The stimulated emission spectrum is considerably narrower than the luminescence spectrum and consists of several narrow lines located within the dye luminescence band. If the luminescence spectrum of a dye (rhodamine 6G) overlaps with the photonic bandgap of the opal matrix, a different picture is observed. The loss of radiation in the matrix leads to the red shift of the luminescence spectrum, while the stimulated emission as in the case of oxazine-17 lies is observed within the luminescence band. (active media, lasers, and amplifiers)

Study of the luminescence properties of dental materials for their use in accidental dosimetry

International Nuclear Information System (INIS)

Veronese, Ivan; Cantone, Marie C.; Guzzi, Gianpaolo

2008-01-01

Full text: The current social and political situation in many world areas and the increasing hostilities between countries and cultures have accentuated the risk of a malicious use of ionising radiations. Terrorist attacks with the intentional disseminations of radioactive materials in urban settlements may involve a large number of persons, and a rapid estimation of the severity of the exposure is required for undertaking suitable protective actions and supporting decision making. Promising methodologies for a prompt dose evaluation, are those exploiting the luminescence and dosimetric properties of objects and materials which can be easily found in the contaminated area. Among these objects, dental materials have the advantage to be on contact with human body and they could therefore represent individual dosimeters in case of accidental exposure to ionising radiation. The interest in the use of dental ceramics for dosimetric purposes dates back to late 1970, however, it is only through the use of high-sensitive experimental techniques and instrumentation today available, that the potentiality of such materials as accidental dosimeters can be exploited. Moreover, innovative materials are being continuously introduced into the market, containing new additives and pigments with peculiar optical properties. In this study, Thermally Stimulated Luminescence (TSL) and Optically Stimulated Luminescence (OSL) techniques are applied to investigate the luminescence and dosimetric properties of several dental materials, including resins, glass and feldspatic ceramics, and also zirconia and alumina based ceramics, being their use widely increased in the recent years in substitution of metal cores. (author)

Mixing up-conversion excitation behaviors in Er3+/Yb3+-codoped aluminum germanate glasses for visible waveguide devices

International Nuclear Information System (INIS)

Gong, H.; Lin, L.; Zhao, X.; Pun, E.Y.B.; Yang, D.L.; Lin, H.

2010-01-01

A mixing up-conversion excitation phenomenon in Er 3+ /Yb 3+ -codoped aluminum germanate (Na 2 O-MgO-Al 2 O 3 -GeO 2 , NMAG for short) glasses for K + -Na + ion-exchanged waveguides was observed and characterized. The green and red up-conversion luminescence of Er 3+ is due to a two-photon excitation process under low-power excitation of a 974 nm diode laser, however, with increasing the pumping power, the green emission turns to follow a combination of two- and three-photon excitation effects while the red one still agrees with a two-photon excitation law. Under high-power pumping, owing to potential thermal effect, the population ratio between the 2 H 11/2 and 4 S 3/2 levels adjusts acutely, which results in a distinct exhibition in 2 H 11/2 → 4 I 15/2 and 4 S 3/2 → 4 I 15/2 emission transitions. Green transmission trace has been observed in K + -Na + ion-exchanged Er 3+ /Yb 3+ -codoped NMAG glass waveguide and it provides an original reference in developing visible waveguide amplifiers and lasers.

Magnetic-luminescent spherical particles synthesized by ultrasonic spray pyrolysis

International Nuclear Information System (INIS)

Michel, Norma L; Hirata, Gustavo A; Flores, Dora L

2015-01-01

The combination of magnetic and luminescent properties in a single particle system, opens-up a wide range of potential applications in biotechnology and biomedicine. In this work, we performed the synthesis of magnetic-luminescent Gd 2 O 3 :Eu 3+ @Fe 2 O 3 particles by ultrasonic spray pyrolysis performed in a tubular furnace. In order to achieve the composite formation, commercial superparamagnetic Fe 3 O 4 nanoparticles were coated with a luminescent Eu 3+ -doped Gd 2 O 3 shell in a low-cost one-step process. The spray pyrolysis method yields deagglomerated spherical shape magneto/luminescent particles. The photoluminescence spectra under UV excitation (λ Exc = 265 nm) of the magnetic Gd 2 O 3 :Eu 3+ @Fe 2 O 3 compound showed the characteristic red emission of Eu 3+ (λ Em = 612 nm). This magneto/luminescent system will find applications in biomedicine and biotechnology. (paper)

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.

Magnetic and luminescent properties of vanadium-doped ZnSe crystals

Energy Technology Data Exchange (ETDEWEB)

Radevici, Ivan, E-mail: ivarad@utu.fi [Wihuri Physical Laboratory, Department of Physics and Astronomy, University of Turku, FI-20014 Turku (Finland); Faculty of Physics and Engineering, Moldova State University, 60 A. Mateevici str., MD-2009 Chisinau (Moldova, Republic of); Nedeoglo, Natalia; Sushkevich, Konstantin [Faculty of Physics and Engineering, Moldova State University, 60 A. Mateevici str., MD-2009 Chisinau (Moldova, Republic of); Huhtinen, Hannu [Wihuri Physical Laboratory, Department of Physics and Astronomy, University of Turku, FI-20014 Turku (Finland); Nedeoglo, Dmitrii [Faculty of Physics and Engineering, Moldova State University, 60 A. Mateevici str., MD-2009 Chisinau (Moldova, Republic of); Paturi, Petriina [Wihuri Physical Laboratory, Department of Physics and Astronomy, University of Turku, FI-20014 Turku (Finland)

2016-12-15

Magnetic and photoluminescence properties of vanadium-doped ZnSe crystals with impurity concentrations varied by changing the V amount in the source material from 0.03 to 0.30 at% are studied in 5–300 K temperature range. Investigation of magnetic properties shows that the studied concentrations of vanadium impurity that should not disturb crystal lattice are insignificant for observing ferromagnetic behaviour even at low temperatures. The contribution of V impurity to edge emission and its influence on infra-red emission are discussed. Similarities of magnetic and luminescent properties induced by vanadium and other transition metal impurities are discussed.

Highly photoluminescent and photostable CdSe quantum dot-nylon hybrid composites for efficient light conversion applications

Energy Technology Data Exchange (ETDEWEB)

Yuan Ying; Riehle, Frank-Stefan [Freiburg Materials Research Centre (FMF), University of Freiburg, Stefan-Meier-Str. 21, D-79104 Freiburg (Germany); Department of Microsystems Engineering (IMTEK), Georg Koehler Allee 103, University of Freiburg, D-79110 Freiburg (Germany); Nitschke, Roland [Life Imaging Center, Centre of Systems Biology, University of Freiburg Habsburgerstr. 49, D-79104 Freiburg (Germany); Centre for Biological Signalling Studies (BIOSS), University of Freiburg (Germany); Krueger, Michael, E-mail: michael.krueger@fmf.uni-freiburg.de [Freiburg Materials Research Centre (FMF), University of Freiburg, Stefan-Meier-Str. 21, D-79104 Freiburg (Germany); Department of Microsystems Engineering (IMTEK), Georg Koehler Allee 103, University of Freiburg, D-79110 Freiburg (Germany)

2012-02-15

Highlights: Black-Right-Pointing-Pointer A novel in situ synthesis approach for highly luminescent CdSe core QDs-nylon hybrid materials. Black-Right-Pointing-Pointer Potential applications for light and energy conversion are demonstrated. Black-Right-Pointing-Pointer Three dimensional structures out of this hybrid material are available. - Abstract: Highly photoluminescent hexadecylamine (HDA) capped core CdSe quantum dots (QDs) with fluorescent quantum yields (QYs) up to 60% were synthesized using a hot injection method and directly incorporated into nylon polymer. For the incorporation of crude CdSe QDs into nylon a simple reproducible and upscalable one pot approach was developed without the need of further purification steps. The photoluminescence (PL) properties of the core QDs and the resulting QD-polymer hybrid composites were investigated and compared. Red emitting hybrid materials exhibit a QY of 60% with a high potential for applications in direct light and energy conversion. The hybrid materials could be successfully utilized as LED conversion layers. By avoiding exposure to oxygen the hybrid films can be kept for a month without detecting a significant decrease in luminescence. Various three dimensional structures are easily available opening doors for further applications such as novel materials for fluorescence standard development in laser scanning microscopy (LSM).

Characterization and luminescent properties of Eu3+ doped Gd2Zr2O7 nanopowders

International Nuclear Information System (INIS)

Rabasovic, M.S.; Sevic, D.; Krizan, J.; Terzic, M.; Mozina, J.; Marinkovic, B.P.; Savic-Sevic, S.; Mitric, M.; Rabasovic, M.D.; Romcevic, N.

2015-01-01

Highlights: • Nanopowders Gd 2 Zr 2 O 7 doped by europium ions (Eu 3+ ) have been synthesized. • Their luminescence properties have been measured at room temperature. • The temporal evolution of laser induced phenomena are presented using time-resolved technique. • Lifetime analysis for luminescence bands in emission spectra has been done. - Abstract: Nanopowders based on gadolinium zirconium oxide (Gd 2 Zr 2 O 7 ) doped by europium ions (Eu 3+ ) were successfully prepared using a flame combustion method. This material is suitable for various optical devices. The structure of prepared materials has been confirmed and characterized using X-ray powder diffraction (XRD), scanning electron microscope (SEM) and photoluminescence (PL) techniques. The luminescence properties of synthesized nanopowders were characterized by emission spectra and luminescence lifetimes by using the streak camera system. PL spectra were obtained at three different excitation wavelengths (Optical Parametric Oscilator (OPO) at 360 nm, laser diode at 365 nm and Ar laser line at 514.5 nm). The strong emission lines at 611 nm and 630 nm corresponding to the 5 D 0 → 7 F 2 long lived transition could be used as a new red light source in optical devices

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

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.

Synthesis and luminescence properties of europium and terbium complexes with pyridine- or bipyridine-linked oligothiophene ligand

International Nuclear Information System (INIS)

Liu Ping; Huang Mingsheng; Pan Wanzhang; Zhang Yamin; Hu Jianhua; Deng Wenji

2006-01-01

With an aim to develop novel luminescence materials, europium and terbium complexes of 2,5-(2-thiophene)-pyridine (TPY) and 5,5'-bis(5-(2,2'-bithiophene))-2,2'-bipyridine (B2TBPY) were synthesized, and their luminescence properties studied. The complexes exhibit ligand-sensitized emission, which is typical of Eu(III) and Tb(III) ions

X-ray photoemission spectroscopy investigation of CaTiO3:Eu for luminescence property: effect of Eu3+ ion

International Nuclear Information System (INIS)

Wang, Kaichen; Zhao, Baijun; Gao, Lu

2016-01-01

Graphical abstract: The influence on the photoluminescent performance due to the electronic structure change in Eu-doped CaTiO 3 of the specific core-level and valence band spectrum via X-ray photoemission spectroscopy were characterized. - Highlights: • Single phase CaTiO 3 and CaTiO 3 : Eu crystals were prepared under mild hydrothermal method. • Crystal structure, doping level and the relations to their luminescent property were discussed. • Charge compensation mechanism was discussed via valance band spectrum by XPS. - Abstract: Charge compensation of on-site Eu 4f–5d transition that determines the luminescent performance was confirmed with valance band spectrum. Influence of photoelectrons from CaTiO 3 : Eu to the corresponding luminescent performance was discussed based on the crystal structure, doping level and the relations to their luminescent property. This paper is important to further optimize the luminescent performance for improving the efficiency and reducing the cost in light emitting diode industry.

Supramolecular assembly of borate with quaternary ammonium: Crystal structure and tunable luminescent properties

Energy Technology Data Exchange (ETDEWEB)

Liang, Jie; Wang, Yong-gang [Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China); Wang, Ying-xia, E-mail: wangyx@pku.edu.cn [Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China); Liao, Fu-hui [Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China); Lin, Jian-hua, E-mail: jhlin@pku.edu.cn [Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China)

2013-04-15

A new borate [C{sub 6}H{sub 16}N][B{sub 5}O{sub 6}(OH){sub 4}] (1) is synthesized hydrothermally by the reaction of isopropyltrimethylammonium hydroxide with boric acid. It crystallizes in the triclinic space group P-1 with the parameters a=9.1578(10) Å, b=9.372(9) Å, c=9.9812(10) Å, α=66.508(2)°, β=74.751(2)°, γ=81.893(2)°. The [B{sub 5}O{sub 6}(OH){sub 4}]{sup −} anions are interlinked via hydrogen bonding forming a 3D supramolecular network containing large cavities, where reside the (CH{sub 3}){sub 3}(i-C{sub 3}H{sub 7}) N{sup +} cations. This borate shows tunable luminescent properties with temperature, heating-treatment, exciting-light, and solvents. The fluorescent intensity of 1 enhances 6-fold with decreasing the temperature from 25 K to 78 K. By treatment under different temperatures, the luminescence of 1 shifted from blue to white and the sample treated at 230 °C emits bright white light to naked eyes. The hybrid borate can disperse in different solvents, and shows a red-shifted and intense emission in polar solvents. - Graphical abstract: The new quaternary ammonium borate [C{sub 6}H{sub 17}N][B{sub 5}O{sub 6}(OH){sub 4}] contains a 3D supramolecular network formed by hydrogen bond linked [B{sub 5}O{sub 6}(OH){sub 4}]{sup −} anions and shows tunable luminescent properties with temperature, excitation light, and solvents. Highlights: ► A novel quaternary ammonium borate was synthesized. ► It possesses a supramolecular network fomed by H-bonded [B{sub 5}O{sub 6}(OH){sub 4}]{sup −} anions. ► This borate shows tunable luminescent properties with temperature, heating treatment, excitation light, and solvents.

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.

Silver Clusters in Zeolites: From Self-Assembly to Ground-Breaking Luminescent Properties.

Science.gov (United States)

Coutiño-Gonzalez, Eduardo; Baekelant, Wouter; Steele, Julian A; Kim, Cheol Woong; Roeffaers, Maarten B J; Hofkens, Johan

2017-09-19

Interest for functional silver clusters (Ag-CLs) has rapidly grown over years due to large advances in the field of nanoscale fabrication and materials science. The continuous development of strategies to fabricate small-scale silver clusters, together with their interesting physicochemical properties (molecule-like discrete energy levels, for example), make them very attractive for a wide variety of applied research fields, from biotechnology and the environmental sciences to fundamental chemistry and physics. Apart from useful catalytic properties, silver clusters (Ag n , n counterbalancing ions, silver loading, and zeolite topology, and cannot be overlooked. This Account is intended to shed light on the current state-of-the-art of luminescent Ag-CLs confined in zeolitic matrices, emphasizing the use of combinatorial approaches to overcome problems associated with the correct characterization and correlation of their structural, electronic, and photoluminescence properties, all to establish the important design principles for developing functional silver-zeolite-based materials. Additionally, examples of emerging applications and future perspectives for functional luminescent Ag-zeolite materials are addressed in this Account.

Scale-up of a Luminescent Solar Concentrator-Based Photomicroreactor via Numbering-up.

Science.gov (United States)

Zhao, Fang; Cambié, Dario; Janse, Jeroen; Wieland, Eric W; Kuijpers, Koen P L; Hessel, Volker; Debije, Michael G; Noël, Timothy

2018-01-02

The use of solar energy to power chemical reactions is a long-standing dream of the chemical community. Recently, visible-light-mediated photoredox catalysis has been recognized as the ideal catalytic transformation to convert solar energy into chemical bonds. However, scaling photochemical transformations has been extremely challenging due to Bouguer-Lambert-Beer law. Recently, we have pioneered the development of luminescent solar concentrator photomicroreactors (LSC-PMs), which display an excellent energy efficiency. These devices harvest solar energy, convert the broad solar energy spectrum to a narrow-wavelength region, and subsequently waveguide the re-emitted photons to the reaction channels. Herein, we report on the scalability of such LSC-PMs via a numbering-up strategy. Paramount in our work was the use of molds that were fabricated via 3D printing. This allowed us to rapidly produce many different prototypes and to optimize experimentally key design aspects in a time-efficient fashion. Reactors up to 32 parallel channels have been fabricated that display an excellent flow distribution using a bifurcated flow distributor (standard deviations below 10%). This excellent flow distribution was crucial to scale up a model reaction efficiently, displaying yields comparable to those obtained in a single-channel device. We also found that interchannel spacing is an important and unique design parameter for numbered-up LSC-PMs, which influences greatly the photon flux experienced within the reaction channels.

Spectroscopic properties of rare earths in optical materials

CERN Document Server

Parisi, Jürgen; Osgood, R; Warlimont, Hans; Liu, Guokui; Jacquier, Bernard

2005-01-01

Aimed at researchers and graduate students, this book provides up-to-date information for understanding electronic interactions that impact the optical properties of rare earth ions in solids. Its goal is to establish a connection between fundamental principles and the materials properties of rare-earth activated luminescent and laser optical materials. The theoretical survey and introduction to spectroscopic properties include electronic energy level structure, intensities of optical transitions, ion-phonon interactions, line broadening, and energy transfer and up-conversion. An important aspect of the book lies in its deep and detailed discussions on materials properties and the potential of new applications such as optical storage, information processing, nanophotonics, and molecular probes that have been identified in recent experimental studies. This volume will be a valuable reference book on advanced topics of rare earth spectroscopy and materials science.

Novel lanthanide doped micro- and mesoporous solids. Characterization of ion-host-interactions, species distribution and luminescence properties using time-resolved luminescence spectroscopy; Neuartige Lanthanoid-dotierte mikro- und mesoporoese Feststoffe. Charakterisierung von Ion-Wirt-Wechselwirkungen, Speziesverteilung und Lumineszenzeigenschaften mittels zeitaufgeloester Lumineszenzspektroskopie

Energy Technology Data Exchange (ETDEWEB)

Gessner, Andre

2010-12-15

mesopores. Lanthanide ions located here, are easily accessible for water and thus show shorter luminescence decay times and a more symmetrical coordination sphere, which is mostly made up by water molecules. Another investigated aspect was the influence of surface modifications on the luminescence behavior of the lanthanide ions inside the material. Here we could show, that surface modifications hydrophobize the material and thus are able to protect the lanthanide ions from water, which is important for the conservation of the luminescence properties. Concerning the mesoporous silicates, again a heterogeneous distribution of the lanthanide ions in the pore system was found. A part of the lanthanide ions interacts with the pore wall, while the other part is located in the aqueous phase inside the pores. Surface modification led to a interaction of the lanthanide ions with the modification. This was reflected in the luminescence properties depending on the structure of the modification and the surface loading.

MOlecular MAterials Property Prediction Package (MOMAP) 1.0: a software package for predicting the luminescent properties and mobility of organic functional materials

Science.gov (United States)

Niu, Yingli; Li, Wenqiang; Peng, Qian; Geng, Hua; Yi, Yuanping; Wang, Linjun; Nan, Guangjun; Wang, Dong; Shuai, Zhigang

2018-04-01

MOlecular MAterials Property Prediction Package (MOMAP) is a software toolkit for molecular materials property prediction. It focuses on luminescent properties and charge mobility properties. This article contains a brief descriptive introduction of key features, theoretical models and algorithms of the software, together with examples that illustrate the performance. First, we present the theoretical models and algorithms for molecular luminescent properties calculation, which includes the excited-state radiative/non-radiative decay rate constant and the optical spectra. Then, a multi-scale simulation approach and its algorithm for the molecular charge mobility are described. This approach is based on hopping model and combines with Kinetic Monte Carlo and molecular dynamics simulations, and it is especially applicable for describing a large category of organic semiconductors, whose inter-molecular electronic coupling is much smaller than intra-molecular charge reorganisation energy.

Principal and secondary luminescence lifetime components in annealed natural quartz

International Nuclear Information System (INIS)

Chithambo, M.L.; Ogundare, F.O.; Feathers, J.

2008-01-01

Time-resolved luminescence spectra from quartz can be separated into components with distinct principal and secondary lifetimes depending on certain combinations of annealing and measurement temperature. The influence of annealing on properties of the lifetimes related to irradiation dose and temperature of measurement has been investigated in sedimentary quartz annealed at various temperatures up to 900 deg. C. Time-resolved luminescence for use in the analysis was pulse stimulated from samples at 470 nm between 20 and 200 deg. C. Luminescence lifetimes decrease with measurement temperature due to increasing thermal effect on the associated luminescence with an activation energy of thermal quenching equal to 0.68±0.01eV for the secondary lifetime but only qualitatively so for the principal lifetime component. Concerning the influence of annealing temperature, luminescence lifetimes measured at 20 deg. C are constant at about 33μs for annealing temperatures up to 600 0 C but decrease to about 29μs when the annealing temperature is increased to 900 deg. C. In addition, it was found that lifetime components in samples annealed at 800 deg. C are independent of radiation dose in the range 85-1340 Gy investigated. The dependence of lifetimes on both the annealing temperature and magnitude of radiation dose is described as being due to the increasing importance of a particular recombination centre in the luminescence emission process as a result of dynamic hole transfer between non-radiative and radiative luminescence centres

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.

Bottom-up synthesis of up-converting submicron-sized Er{sup 3+}-doped LiNbO{sub 3} particles

Energy Technology Data Exchange (ETDEWEB)

Jardiel, T., E-mail: jardiel@icv.csic.es [Departamento de Electroceramica, Instituto de Ceramica y Vidrio-CSIC, Kelsen 5, 28049 Madrid (Spain); Caballero, A.C. [Departamento de Electroceramica, Instituto de Ceramica y Vidrio-CSIC, Kelsen 5, 28049 Madrid (Spain); Marin-Dobrincic, M.; Cantelar, E.; Cusso, F. [Departamento de Fisica de Materiales, C-04, Facultad de Ciencias, Universidad Autonoma de Madrid, Avda. Francisco Tomas y Valiente 7, 28049 Madrid (Spain)

2012-08-15

A new and simple wet chemical synthesis method is proposed to prepare submicron-sized Erbium-doped LiNbO{sub 3} powders. The synthesis procedure comprises the co-precipitation of lithium and erbium ions from common precursors and their subsequent reaction with niobium ethoxide. A systematic characterization by means of X-Ray Diffraction (XRD), X-ray Fluorescence (XRF), Inductively Coupled Plasma (ICP-OES), Atomic Absorption (AAS), Field Emission Scanning Electron Microscopy (FE-SEM), as well as by the examination of the luminescence properties, evidence that with this method a congruent Er{sup 3+}-doped LiNbO{sub 3} single phase material can be obtained without using complex and time-consuming processing steps. The synthesized powders exhibit efficient IR to VIS up-conversion emissions under 974 nm pumping. -- Highlights: Black-Right-Pointing-Pointer A novel chemical route to the preparation of LiNbO{sub 3} powders has been developed. Black-Right-Pointing-Pointer This process avoids complex and time-consuming processing steps. Black-Right-Pointing-Pointer A congruent Er{sup 3+}-doped LiNbO{sub 3} single phase material can be obtained by this way. Black-Right-Pointing-Pointer The luminescence properties are the expected for this composition.

Spectral, luminescent and lasing properties of pyran derivatives

International Nuclear Information System (INIS)

Kopylova, T N; Svetlichnyi, Valerii A; Samsonova, L G; Svetlichnaya, N N; Reznichenko, A V; Ponomareva, O V; Komlev, I V

2003-01-01

The spectral, luminescent and lasing properties of eight organic molecules, substituted pyrans (DCM), are studied upon pumping by an exciplex XeCl laser at 308 nm and by the second harmonic from a Nd:YAG laser at 532 nm. These molecules exhibit lasing in the red spectral region between 600 and 780 nm with the efficiency of 45%. Lasing was also obtained in bis-substituted pyrans having the quantum yield of fluorescence equal to 0.01. The possibility of preparation of solid active media for tunable lasers based on polymer matrices doped with substituted pyrans is discussed. (active media. lasers)

Heterogeneously Nd3+ doped single nanoparticles for NIR-induced heat conversion, luminescence, and thermometry.

Science.gov (United States)

Marciniak, Lukasz; Pilch, Aleksandra; Arabasz, Sebastian; Jin, Dayong; Bednarkiewicz, Artur

2017-06-22

The current frontier in nanomaterials engineering is to intentionally design and fabricate heterogeneous nanoparticles with desirable morphology and composition, and to integrate multiple functionalities through highly controlled epitaxial growth. Here we show that heterogeneous doping of Nd 3+ ions following a core-shell design already allows three optical functions, namely efficient (η > 72%) light-to-heat conversion, bright NIR emission, and sensitive (S R > 0.1% K -1 ) localized temperature quantification, to be built within a single ca. 25 nm nanoparticle. Importantly, all these optical functions operate within the transparent biological window of the NIR spectral region (λ exc ∼ 800 nm, λ emi ∼ 860 nm), in which light scattering and absorption by tissues and water are minimal. We find NaNdF 4 as a core is efficient in absorbing and converting 808 nm light to heat, while NaYF 4 :1%Nd 3+ as a shell is a temperature sensor based on the ratio-metric luminescence reading but an intermediate inert spacer shell, e.g. NaYF 4 , is necessary to insulate the heat convertor and thermometer by preventing the possible Nd-Nd energy relaxation. Moreover, we notice that while temperature sensitivity and luminescence intensity are optically stable, increased excitation intensity to generate heat above room temperature may saturate the sensing capacity of temperature feedback. We therefore propose a dual beam photoexcitation scheme as a solution for possible light-induced hyperthermia treatment.

Implementation of a Monte Carlo method to model photon conversion for solar cells

International Nuclear Information System (INIS)

Canizo, C. del; Tobias, I.; Perez-Bedmar, J.; Pan, A.C.; Luque, A.

2008-01-01

A physical model describing different photon conversion mechanisms is presented in the context of photovoltaic applications. To solve the resulting system of equations, a Monte Carlo ray-tracing model is implemented, which takes into account the coupling of the photon transport phenomena to the non-linear rate equations describing luminescence. It also separates the generation of rays from the two very different sources of photons involved (the sun and the luminescence centers). The Monte Carlo simulator presented in this paper is proposed as a tool to help in the evaluation of candidate materials for up- and down-conversion. Some application examples are presented, exploring the range of values that the most relevant parameters describing the converter should have in order to give significant gain in photocurrent

Luminescent properties of fluorophosphate glasses with lead chalcogenides molecular clusters

International Nuclear Information System (INIS)

Kolobkova, E.V.; Kukushkin, D.S.; Nikonorov, N.V.; Shakhverdov, T.A.; Sidorov, A.I.; Vasiliev, V.N.

2015-01-01

Fluorophosphate glasses containing lead, selenium, and sulfur exhibit an intense luminescence in the 400–620 nm spectral region when excited by the 240–420 nm radiation. This luminescence is due to the presence of (PbSe) n and/or (PbS) n molecular clusters in the glasses, which appear in the as-prepared glasses before quantum dots formation. The thermal treatment at temperatures less than the glass transition temperature results in the red-shift of the luminescence bands and in an increase in the luminescence intensity. Heating the thermally treated glass samples leads to the reversible thermal quenching of the luminescence. - Highlights: • Fluorophosphate glasses with Pb, Se, and S ions contain (PbSe) n or (PbS) n molecular clusters. • (PbSe) n and (PbS) n molecular clusters possess luminescence in the visible with UV excitation. • Heating the glass leads to the reversible thermal quenching of the luminescence

Increasing conversion efficiency of two-step photon up-conversion solar cell with a voltage booster hetero-interface.

Science.gov (United States)

Asahi, Shigeo; Kusaki, Kazuki; Harada, Yukihiro; Kita, Takashi

2018-01-17

Development of high-efficiency solar cells is one of the attractive challenges in renewable energy technologies. Photon up-conversion can reduce the transmission loss and is one of the promising concepts which improve conversion efficiency. Here we present an analysis of the conversion efficiency, which can be increased by up-conversion in a single-junction solar cell with a hetero-interface that boosts the output voltage. We confirm that an increase in the quasi-Fermi gap and substantial photocurrent generation result in a high conversion efficiency.

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.

Luminescent properties in films of ZrO2: Dy

International Nuclear Information System (INIS)

Martinez, R. C.; Guzman, J.; Rivera, T.; Ceron, P.; Montes, E.; Guzman, D.; Garcia H, M.; Falcony, C.; Azorin, J.

2014-08-01

In this work the luminescent characterization of zirconium oxide (ZrO 2 ) films impure with dysprosium (Dy +3 ) is reported, obtained by means of the ultrasonics spray pyrolysis technique. The films were deposited on glass substrates (Corning), in a temperatures interval of 400 to 550 grades C, using as precursor elements Zirconium oxide chloride octahydrate (ZrOCl 2 ·8H 2 O) and Dysprosium tri-chloride (DyCl 3 ), dissolved in deionized water, varying the concentration of the contaminated from the 1 to 20 atomic % with relationship to the zirconium in solution. The luminescent characterization was analyzed by means of photoluminescence and thermoluminescence. The photoluminescence results showed a spectrum with three maxima which correspond to the electronic transitions 4 F 9/2 - 6 H 15/2 , 4 F 9/2 - 6 H 13/2 and 4 F 9/2 - 6 H 11/2 characteristics of the Dy 3+ ion. The thermoluminescence (Tl) response when being exposed to a monochrome UV beam in 240 nm showed a wide curve that exhibits a maxim centered in 200 grades C. The Tl response of ZrO 2 :Dy in function of the dose was shown lineal in the interval of 24 mJ/cm 2 to 432 mJ/cm 2 . A study of the repeatability and dissipation of the ZrO 2 :Dy Tl response is included. Considering the shown previous results we can conclude that the ZrO 2 in film form obtained by spray pyrolysis has luminescent properties in 240 nm. (Author)

Luminescence properties of tetravalent uranium in aqueous solution

International Nuclear Information System (INIS)

Kirishima, A.; Kimura, T.; Nagaishi, R.; Tochiyama, O.

2004-01-01

The luminescence spectra of U 4+ in aqueous solutions were observed in the UV-VIS region at ambient and liquid nitrogen temperatures. The excitation spectrum indicates that the luminescence is arising from the deexcitation of a 5f electron at the 1 S 0 level and no other emissions of U 4+ in aqueous solutions were detected for other f-f transitions. All the luminescence peaks were assigned to the transitions from 1 S 0 to lower 5f levels. To estimate the luminescence lifetime, luminescence decay curves were measured using time-resolved laser-induced fluorescence spectroscopy. At room temperature, the decay curve indicated that the lifetime was shorter than 20 ns. On the other hand, the frozen sample of U 4+ in aqueous solution at liquid nitrogen temperature showed the same emission spectrum as at room temperature and its lifetime was 149 ns in H 2 O system and 198 ns in D 2 O system. The longer lifetime at liquid nitrogen temperature made it possible to measure the spectrum of U 4+ at the concentration as low as 10 -6 M. The difference in the anion species (ClO 4 - , Cl - , SO 4 2- ) affected the structure of the emission spectrum to some extent. (orig.)

Luminescent properties of terbium complex with phenylanthranilic acid

International Nuclear Information System (INIS)

Alakaeva, L.A.; Kalazhokova, I.A.; Naurzhanova, F.Kh.

1990-01-01

Existence of terbium luminescence reaction in complex with phenanthranilic acid (FAA) is ascertained. The optimal conditions of terbium complexing with FAA are found. The ratio of components in the complex is 1:1. The influence of foreign rare earth in terbium luminescence intensity in complex with FAA is studied

Luminescent and magnetic properties of Fe{sub 3}O{sub 4}@SiO{sub 2}:phen:Eu{sup 3+}

Energy Technology Data Exchange (ETDEWEB)

Silva, Raphael Lucas de Sousa; Figueiredo, Alberthmeiry Teixeira de; Barrado, Cristiano Morita, E-mail: alberth@ufg.br [Universidade Federal de Goiás (UFG), Catalão, GO (Brazil). Departamento de Química; Sousa, Marcelo Henrique [Universidade de Brasília (UnB), DF (Brazil). Faculdade de Ceilândia

2017-10-15

Magnetite was doped with rare earth ions (europium) to produce core-shell materials with both magnetic and luminescent properties, i.e., a magnetic Fe{sub 3}O{sub 4} oxide core and a SiO{sub 2} :phen:Eu{sup 3+} shell. The resulting material was analyzed by X-ray powder diffraction and transmission electron microscopy, and subjected to magnetic and luminescence emission measurements. All the synthesized materials exhibited superparamagnetic behavior and luminescence emission. The magnetic behavior of Fe{sub 3}O{sub 4} and luminescence emission of SiO{sub 2} :phen:Eu{sup 3+} of the materials were compared to precursors. (author)

Phase transition control, melt growth of (Gd,RE)F{sub 3} single crystal and their luminescent properties

Energy Technology Data Exchange (ETDEWEB)

Yoshikawa, Akira, E-mail: yosikawa@tagen.tohoku.ac.j [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); New Industry Creation Hatchery Center (NICHe), Tohoku University, 6-6-10 Aoba, Aramaki, Aoba-ku, Sendai 980-8579 (Japan); Jouini, Anis [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); BerlinSolar GmbH, Magnusstrasse 11, D-12489 Berlin (Germany); Kamada, Kei [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Boulon, Georges [Physical Chemistry of Luminescent Materials, Claude Bernard/Lyon 1 University, UMR 5620 CNRS, Villeurbanne (France); Nikl, Martin [Institute of Physics AS CR, Cukrovarnicka 10, Prague 16253 (Czech Republic); Saito, Fumio [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan)

2009-12-15

Rare-earth sesquifluorides with no absorption in visible spectral region, such as LaF{sub 3}, GdF{sub 3}, LuF{sub 3}, YF{sub 3}, ScF{sub 3}, are the topic of intense study as a host for luminescence materials. However, except Nd:LaF{sub 3}, they are not studied as a host for laser materials. The main obstacle troubling further study of GdF{sub 3}, LuF{sub 3}, YF{sub 3}, ScF{sub 3} single crystal is the fact that there is first-order phase transition (LaF{sub 3} type{leftrightarrow}{beta}-YF{sub 3} type for GdF{sub 3}, {alpha}-YF{sub 3} type{leftrightarrow}{beta}-YF{sub 3} type for the rest) between the room and melting temperature.To prevent the phase transition, first of all, we have tried to make solid solution between GdF{sub 3} and YF{sub 3} in such a way that the average cation radii can be shifted to the size that does not have phase transition. Ce{sup 3+} perturbed luminescence was observed in the Ce- and Sr-codoped GdF{sub 3}-YF{sub 3} system. Similar solid solution concept was applied to the combination between GdF{sub 3} and YbF{sub 3}. The emission spectrum of Yb{sup 3+} that exhibits broad bands around 1 {mu}m was observed. Room temperature up-conversion luminescence spectra of Pr{sup 3+}-doped Gd{sub 1-x}Yb{sub x}F{sub 3} were studied and visible emission from Pr{sup 3+} was obtained under infrared laser pumping in the Yb{sup 3+} broad absorption band at 935.5 nm.

Near-infrared (NIR) optogenetics using up-conversion system

Science.gov (United States)

Hososhima, Shoko; Yuasa, Hideya; Ishizuka, Toru; Yawo, Hiromu

2015-03-01

Non-invasive remote control technologies designed to manipulate neural functions for a comprehensive and quantitative understanding of the neuronal network in the brain as well as for the therapy of neurological disorders have long been awaited. Recently, it has become possible to optically manipulate the neuronal activity using biological photo-reactive molecules such as channelrhodopsin-2 (ChR2). However, ChR2 and its relatives are mostly reactive to visible light which does not effectively penetrate through biological tissues. In contrast, near-infrared (NIR) light penetrates deep into the tissues because biological systems are almost transparent to light within this so-called `imaging window'. Here we used lanthanide nanoparticles (LNPs), which are composed of rare-earth elements, as luminous bodies to activate channelrhodopsins (ChRs) since they absorb low-energy NIR light to emit high-energy visible light (up-conversion). Neuron-glioma-hybrid ND-7/23 cells were cultured with LNP(NaYF4:Sc/Yb/Er) particles (peak emission, 543 nm) and transfected to express C1V1 (peak absorbance, 539 nm), a chimera of ChR1 and VChR1. The photocurrents were generated in response to NIR laser light (976 nm) to a level comparable to that evoked by a filtered Hg lamp (530-550 nm). NIR light pulses also evoked action potentials in the cultured neurons that expressed C1V1. It is suggested that the green luminescent light emitted from LNPs effectively activated C1V1 to generate the photocurrent. With the optimization of LNPs, acceptor photo-reactive biomolecules and optics, this system could be applied to non-invasively actuate neurons deep in the brain.

Luminescence Properties of Surface Radiation-Induced Defects in Lithium Fluoride

Science.gov (United States)

Voitovich, A. P.; Kalinov, V. S.; Martynovich, E. F.; Novikov, A. N.; Runets, L. P.; Stupak, A. P.

2013-11-01

Luminescence and luminescence excitation spectra are recorded for surface radiation-induced defects in lithium fluoride at temperatures of 77 and 293 K. The presence of three bands with relatively small intensity differences is a distinctive feature of the excitation spectrum. These bands are found to belong to the same type of defects. The positions of the peaks and the widths of the absorption and luminescence bands for these defects are determined. The luminescence decay time is measured. All the measured characteristics of these surface defects differ from those of previously known defects induced by radiation in the bulk of the crystals. It is found that the luminescence of surface defects in an ensemble of nanocrystals with different orientations is not polarized. The number of anion vacancies in the surface defects is estimated using the polarization measurements. It is shown that radiative scattering distorts the intensity ratios of the luminescence excitation bands located in different spectral regions.

Analysis of structure origin and luminescence properties of Yb(3+)-Er(3+) co-doped fluorophosphate glass.

Science.gov (United States)

Chen, Fangze; Jing, Xufeng; Wei, Tao; Wang, Fengchao; Tian, Ying; Xu, Shiqing

2014-08-14

The near infrared luminescence properties of Yb(3+)-Er(3+) co-doped fluorophosphate glasses have been investigated. The various effects on structure and 1.53 μm emission were analyzed as a function of Yb(3+) concentration. The energy transfer mechanism was proposed. High measured lifetime (10.75 ms), large effective full widths at half maximum (73.71 nm) and large gain per unit length (62.8 × 10(-)(24)cm(2)s) have been achieved in prepared glass. The present glass co-doped with 6mol% YbF3 and 2 mol% ErF3 showed magnificent luminescence properties for telecommunication application. Copyright © 2014 Elsevier B.V. All rights reserved.

Advantages and disadvantages of luminescence dosimetry

Energy Technology Data Exchange (ETDEWEB)

Olko, Pawel, E-mail: Pawel.Olko@ifj.edu.p [Institute of Nuclear Physics Polish Academy of Science (IFJ PAN), Krakow (Poland)

2010-03-15

Owing to their excellent dosimetric properties, luminescence detectors of ionizing radiation are now extensively applied in individual dosimetry services. The most frequently used personal dosemeters are based on Optically Stimulated Luminescence (OSL), radiophotoluminescence (RPL) or thermoluminescence (TL). Luminescence detectors have also found several applications in clinical dosimetry, especially around new radiation modalities in radiotherapy, such as Intensity Modulated Radiotherapy (IMRT) or ion beam radiotherapy. Requirements of luminescence detectors applied in individual and clinical dosimetry and some recent developments in luminescence of detectors and techniques leading to significant improvements of the functionality and accuracy of dosimetry systems are reviewed and discussed.

Light distribution system comprising spectral conversion means

DEFF Research Database (Denmark)

2012-01-01

, longer wavelength,a spectral conversion characteristics of the spectral conversion fibre being essentially determined by the spectral absorption and emission properties of the photoluminescent agent, the amount of photo- luminescent agent,and the distribution of the photoluminescent agent in the spectral......System (200, 300) for the distribution of white light, having a supply side (201, 301, 401) and a delivery side (202, 302, 402), the system being configured for guiding light with a multitude of visible wavelengths in a propagation direction P from the supply side to the distribution side...... of providing a light distribution system and a method of correcting the spectral transmission characteristics of a light distribution system are disclosed....

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.)

Luminescence properties of different Eu sites in LiMgPO4:Eu2+, Eu3+

International Nuclear Information System (INIS)

Baran, A; Mahlik, S; Grinberg, M; Cai, P; Kim, S I; Seo, H J

2014-01-01

The effect of temperature on the luminescence properties of LiMgPO 4 doped with Eu 3+ and Eu 2+ are presented. Depending on the excitation wavelength, luminescence spectra consist of two distinct broad emission bands peaking at 380 nm and 490 nm related to 4f 6 5d 1  → 4f 7 ( 8 S 7/2 ) luminescence of Eu 2+ and to europium-trapped exciton, respectively, and/or several sharp lines between the 580 nm and 710 nm region, ascribed to the 5 D 0  →  7 F J (J = 0, 1, 2, 3 and 4) transitions in Eu 3+ . To explain all the features of the Eu 2+ and Eu 3+ luminescence we discussed the existence of two different Eu sites substituting for Li + , with short and long distance compensation. The evident effect of increasing the intensity of the Eu 2+ luminescence with increasing temperature was observed. It was considered that the charge compensation mechanism for Eu 3+ and Li + as well as Eu 2+ replacing Li + in the LiMgPO 4 is a long distance compensation that allows for the existence of some of the europium ions either as Eu 3+ at low temperature or as Eu 2+ at high temperature. We concluded that Eu 2+ in the Li + site with long distance compensation yields only 4f 6 5d 1  → 4f 7 luminescence, whereas Eu 2+ in the Li + site with short distance compensation yields 4f 6 5d 1  → 4f 7 luminescence and europium-trapped exciton emission. (paper)

Synthesis, crystal structures and luminescent properties of zinc(II) metal–organic frameworks constructed from terpyridyl derivative ligand

International Nuclear Information System (INIS)

Yang, Xiao-Le; Shangguan, Yi-Qing; Hu, Huai-Ming; Xu, Bing; Wang, Bao-Cheng; Xie, Juan; Yuan, Fei; Yang, Meng-Lin; Dong, Fa-Xin; Xue, Gang-Lin

2014-01-01

Five zinc(II) metal–organic frameworks, [Zn 3 (344-pytpy) 2 Cl 6 ] n ·n(H 2 O) (1), [Zn(344-pytpy)(ox)] n (2), [Zn 2 (344-pytpy)(bdc) 2 ] n ·1.5n(H 2 O) (3), [Zn 2 (344-pytpy) 2 (sfdb) 2 ] n ·1.5n(H 2 O) (4) and [Zn 3 (344-pytpy) 2 (btc) 2 ] n ·2n(H 2 O) (5), (344-pytpy=4′-(3-pyridyl)-4,2′:6′,4″-terpyridine, H 2 ox=oxalic acid, H 2 bdc=1,4-benzenedi-carboxylic acid, H 2 sfdb=4,4′-sulfonyldibenzoic acid and H 3 btc=1,3,5-benzene-tricarboxylic acid) have been prepared by hydrothermal reactions. Compound 1 is a 1D chain structure, in which 344-pytpy ligand links three Zn II centers through three of terminal N-donors. Compound 2 is a 4-connected 3D framework with the dia topological net and the Schläfli symbol of 6 6 . Compound 3 displays a unusual 3-fold interpenetrating 3D coordination network which exhibits a new intriguing (3,3,4)-connected topological net with the Schläfli symbol of (4.8 2 )(4.8 5 )(8 3 ). Compound 4 features a two-fold interpenetrating 4-connected 2D framework with the sql topological net and the Schläfli symbol of (4 4 .6 2 ). Compound 5 is a new self-interpenetrating (3,3,4,4)-connected topological net with the Schläfli symbol of (6.8 2 ) 2 (6 2 .8 2 .10.12)(6 2 .8 3 .10) 2 (6 2 .8) 2 . The luminescence properties of 1–5 have been investigated by emission spectra and they possess great thermal stabilities which can be stable up to around 400 °C. - Graphical abstract: Five new Zn(II) metal–organic frameworks based on dicarboxylate and terpyridyl derivative ligands have been synthesized by hydrothermal reactions, giving networks from 1D to 3D structures. The thermal stability and luminescent property have been investigated. - Highlights: • Five zinc(II) metal–organic frameworks have been prepared under hydrothermal conditions. • Their crystal and topological structures have been investigated. • The luminescent properties have been investigated. • They possess great thermal stabilities which can be stable up to

Synthesis and luminescence properties of Eu"2"+ doped CaSO_4 phosphor

International Nuclear Information System (INIS)

Aghalte, G.A.; Dhoble, S.J.; Pawar, N.R.

2016-01-01

Eu"2"+ doped CaSO_4 Phosphor were synthesized by precipitation method. PL analysis of Eu"2"+ activated CaSO_4 phosphor exhibited characteristic emission properties; CaSO_4:Eu Phosphor has received considerable attention because of its high sensitivity to X-ray and λ ray irradiation. CaSO_4:Eu phosphor powder was successfully synthesized by the wet chemical co-precipitation method. The structure morphology and luminescent properties of the phosphor were characterized by X-ray diffraction, scanning electron microscopy and photoluminescence spectroscopy

Violet stimulated luminescence dating of quartz from Luochuan (Chinese loess plateau): Agreement with independent chronology up to ∼600 ka

DEFF Research Database (Denmark)

Ankjærgaard, C.; Guralnik, B.; Buylaert, Jan-Pieter

2016-01-01

Luminescence dating at the Luochuan loess type (China) section is at present limited to ∼0.1 Ma using quartz blue light stimulated luminescence (BLSL), but can be extended back in time to ∼0.5 Ma by resorting to the more developmental post-infrared infrared stimulated luminescence (post-IR IRSL...... demonstrate that the Multi-Aliquot Additive-Dose (MAAD) protocol produces a VSL chronology at Luochuan which is in agreement with independent ages up to ∼0.6 Ma. For a more representative environmental dose rate of ∼2 Gy/ka (∼35% lower than at Luochuan), the documented range of MAAD-VSL sensitivity (200...

Synthesis and luminescence properties of erbium silicate thin films

International Nuclear Information System (INIS)

Miritello, Maria; Lo Savio, Roberto; Iacona, Fabio; Franzo, Giorgia; Bongiorno, Corrado; Priolo, Francesco

2008-01-01

We have studied the structure and the room temperature luminescence of erbium silicate thin films deposited by rf magnetron sputtering. Films deposited on silicon oxide layers are characterized by good structural properties and excellent stability. The optical properties of these films are strongly improved by rapid thermal annealing processes performed in the range of temperature 800-1250 deg. C. In fact through the reduction of the defect density of the material, a very efficient room temperature photoluminescence at 1535 nm is obtained. We have also investigated the influence of the annealing ambient, by finding that treatments in O 2 atmosphere are significantly more efficient in improving the optical properties of the material with respect to processes in N 2 . Upconversion effects become effective only when erbium silicate is excited with high pump powers. The evidence that all Er atoms (about 10 22 cm -3 ) in erbium silicate films are optically active suggests interesting perspectives for optoelectronic applications of this material

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)

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)

X-ray excited luminescence of polystyrene composites loaded with SrF{sub 2} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Demkiv, T.M.; Halyatkin, O.O.; Vistovskyy, V.V. [Ivan Franko National University of Lviv, 8a Kyryla i Mefodiya St., 79005 Lviv (Ukraine); Hevyk, V.B. [Ivano-Frankivsk National Technical University of Oil and Gas, 15 Karpatska St., 76019 Ivano-Frankivsk (Ukraine); Yakibchuk, P.M. [Ivan Franko National University of Lviv, 8a Kyryla i Mefodiya St., 79005 Lviv (Ukraine); Gektin, A.V. [Institute for Scintillation Materials, NAS of Ukraine, 60 Lenina Ave, 61001 Kharkiv (Ukraine); Voloshinovskii, A.S. [Ivan Franko National University of Lviv, 8a Kyryla i Mefodiya St., 79005 Lviv (Ukraine)

2017-03-01

The polystyrene film nanocomposites of 0.3 mm thickness with embedded SrF{sub 2} nanoparticles up to 40 wt% have been synthesized. The luminescent and kinetic properties of the polystyrene composites with embedded SrF{sub 2} nanoparticles upon the pulse X-ray excitation have been investigated. The luminescence intensity of the pure polystyrene scintillator film significantly increases when it is loaded with the inorganic SrF{sub 2} nanoparticles. The film nanocomposites show fast (∼2.8 ns) and slow (∼700 ns) luminescence decay components typical for a luminescence of polystyrene activators (p-Terphenyl and POPOP) and SrF{sub 2} nanoparticles, respectively. It is revealed that the fast decay luminescence component of the polystyrene composites is caused by the excitation of polystyrene by the photoelectrons escaped from the nanoparticles due to photoeffect, and the slow component is caused by reabsorption of the self-trapped exciton luminescence of SrF{sub 2} nanoparticles by polystyrene.

Luminescence sensitivity changes in quartz

CERN Document Server

Wintle, A G

1999-01-01

In the luminescence dating of sedimentary or heated quartz, some heat treatment is usually applied to the sample immediately prior to the measurement of the optically stimulated luminescence. In this paper we report experiments on a 30,000-year-old sedimentary quartz, in which we use the luminescence response to a test dose to monitor the changes in sensitivity that are caused by holding the quartz at temperatures from 160 to 280 deg. C for times from 10 s to 22 h. For an optically bleached sample, the monitoring is by both optically stimulated luminescence and the 110 deg. C TL peak; both luminescence signals are shown to have the same sensitisation (i.e. activation energy) characteristics. For natural or laboratory irradiated samples only the 110 deg. C TL peak can be used; sensitivity increases of up to a factor of 1.3 and 3 are observed for the natural and laboratory irradiated aliquots, respectively. Up to four exponential components are used to deconvolve the sensitivity change data; the dominant compon...

Effect of structure, size and copper doping on the luminescence properties of ZnS

Energy Technology Data Exchange (ETDEWEB)

Kamal, Ch. Satya [Crystal Growth and Nanoscience Research Centre, Government College (A), Rajahmundry, Andhra Pradesh 533 105 (India); Mishra, R.K. [Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Patel, Dinesh K. [Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Casali Center for Applied Chemistry, The Hebrew University of Jerusalem, 9190401 (Israel); Rao, K. Ramachandra, E-mail: drkrcr@gmail.com [Crystal Growth and Nanoscience Research Centre, Government College (A), Rajahmundry, Andhra Pradesh 533 105 (India); Sudarsan, V., E-mail: vsudar@barc.gov.in [Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Vatsa, R.K. [Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

2016-09-15

Highlights: • Blue and green emission intensity form ZnS is sensitive to crystallographic form. • For ZnS nanoparticles, emission characteristics are not affected by copper doping. • Cu solubility poor in ZnS nanoparticles compared to corresponding bulk. - Abstract: Luminescence properties of wurtzite and cubic forms of bulk ZnS have been investigated in detail and compared with that of ZnS nanoparticles. Blue emission observed in both hexagonal and cubic forms of undoped bulk ZnS is explained based on electron–hole recombination involving electron in conduction band and hole trapped in Zn{sup 2+} vacancies where as green emission arises due to electron hole recombination from Zn{sup 2+} and S{sup 2−} vacancies. Conversion of wurtzite form to cubic form is associated with relative increase in intensity of green emission due to increased defect concentration brought about by high temperature heat treatment. Copper doping in ZnS, initially leads to formation of both Cu{sub Zn} and Cu{sub i} (interstitial copper) centers, and latter to mainly Cu{sub Zn} centers as revealed by variation in relative intensities of blue and green emission from the samples.

Effects of nanostructuring on luminescence properties of SrS:Ce,Sm phosphor: An experimental and phenomenological study

Science.gov (United States)

Yazdanmehr, Mohsen; Sadeghi, Hossein; Tehrani, Masoud Kavosh; Hashemifar, Seyed Javad; Mahdavi, Mohammad

2018-01-01

In this work, we employ various experimental techniques to illustrate the effects of nanostructuring on improvement of the luminescence properties of the polycrystalline SrS co-activated by cerium and samarium dopants (SrS : Ce , Sm). The nano and microstructure SrS : Ce , Sm powders were synthesized by the co-precipitation and solid state diffusion methods, respectively, followed by the spark plasma sintering (SPS) process to densify powders into pellet shape. It is observed that the photo-luminescence (PL), radio-luminescence (RL), and optically stimulated luminescence (OSL) emission intensity of the nanostructure samples are significantly improved with respect to the microstructure samples. Moreover, by using an accurate photomultiplier tube, we measured the CW-OSL decay curves of the samples to demonstrate much higher and faster sensitivity of the nanostructure SrS : Ce , Sm for in-flight and online OSL radiation dosimetry. The obtained absorption and emission spectra are used for phenomenology of the electronic band structure of the SrS : Ce , Sm micro and nano-phosphors inside the band gap. The proposed phenomenological electronic structures are then used to clarify the role of Ce3+ and Sm3+ localized energy levels in the luminescence properties of the nano and microstructure samples. It is argued that electronic transitions from the 2T2g state of Ce3+ and the 4G5/2 state of Sm3+ have strong contribution to the PL and RL emission spectra, while in the OSL mechanism, the Sm3+ 4G5/2 state is mainly responsible for electrons trapping.

Luminescent properties of Ln3+ doped tellurite glasses containing AlF3

Science.gov (United States)

Walas, Michalina; Pastwa, Agata; Lewandowski, Tomasz; Synak, Anna; Gryczyński, Ignacy; Sadowski, Wojciech; Kościelska, Barbara

2016-09-01

The low-phonon energy tellurite glasses TeO2-BaO-Bi2O3 and TeO2-BaO-Bi2O3-AlF3 triply doped with Eu3+, Tb3+, Tm3+ ions in two different molar ratios were synthesized using melt-quenching technique. Their structure and luminescence properties were widely investigated by X-ray Diffraction (XRD), Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR) and Photoluminescence Spectroscopy (PL). The luminescence spectra of Eu3+, Tb3+, Tm3+ co-doped glasses show apart of the bands corresponding to the 4f-4f transitions of lanthanide ions also band corresponding to glass matrix. AlF3 doping increases emission intensity, although to improve overall emission color further studies on molar composition of samples and the molar ratio of the components should be carried out.

Luminescence properties of isomeric and tautomeric lanthanide pyridinedicarboxylates

International Nuclear Information System (INIS)

Puntus, L.N.; Zolin, V.F.; Babushkina, T.A.; Kutuza, I.B.

2004-01-01

The luminescence and PMR spectra of europium salts of six isomers of 2,3-, 2,4-, 2,5-, 2,6-, 3,4-, and 3,5-pyridinedicarboxylic acids (PDA) had been studied. The distribution of the effective charge in the nearest surroundings of the Eu 3+ ion in these salts was evaluated from Stark splittings of electronic transitions. The values of relative integral intensities of electronic transitions 5 D 0 - 7 F J (J=0-4) in the luminescence spectra were reported. Compounds investigated were divided into three subgroups taking into account the details of the structure of the ligands and details of the luminescence spectra. The ligand coordination manners as well as the strength of interaction between lanthanide ion and ligands were confirmed by data of the PMR and IR spectroscopy

Luminescence in Sulfides: A Rich History and a Bright Future

Directory of Open Access Journals (Sweden)

Philippe F. Smet

2010-04-01

Full Text Available Sulfide-based luminescent materials have attracted a lot of attention for a wide range of photo-, cathodo- and electroluminescent applications. Upon doping with Ce3+ and Eu2+, the luminescence can be varied over the entire visible region by appropriately choosing the composition of the sulfide host. Main application areas are flat panel displays based on thin film electroluminescence, field emission displays and ZnS-based powder electroluminescence for backlights. For these applications, special attention is given to BaAl2S4:Eu, ZnS:Mn and ZnS:Cu. Recently, sulfide materials have regained interest due to their ability (in contrast to oxide materials to provide a broad band, Eu2+-based red emission for use as a color conversion material in white-light emitting diodes (LEDs. The potential application of rare-earth doped binary alkaline-earth sulfides, like CaS and SrS, thiogallates, thioaluminates and thiosilicates as conversion phosphors is discussed. Finally, this review concludes with the size-dependent luminescence in intrinsic colloidal quantum dots like PbS and CdS, and with the luminescence in doped nanoparticles.

The nature of unusual luminescence in natural calcite, CaCO3

Energy Technology Data Exchange (ETDEWEB)

Gaft, M.; Nagli, L.; Panczer, G.; Waychunas, G.; Porat, N.

2008-11-01

The unusual luminescence of particular varieties of natural pink calcite (CaCO{sub 3}) samples was studied by laser-induced time-resolved luminescence spectroscopy at different temperatures. The luminescence is characterized by intense blue emission under short-wave UV lamp excitation with an extremely long decay time, accompanied by pink-orange luminescence under long wave UV excitation. Our investigation included optical absorption, natural thermostimulated luminescence (NTL) and Laser-Induced Breakdown Spectroscopy (LIBS) studies. Two luminescence centers were detected: a narrow violet band, with {lambda}{sub max} = 412 nm, {Delta} = 45 nm, two decay components of {tau}{sub 1} = 5 ns and {tau}{sub 2} = 7.2 ms, accompanied by very long afterglow, and an orange emission band with {lambda}{sub max} = 595 nm, {Delta} = 90 nm and {tau} = 5 ns. Both luminescence centers are thermally unstable with the blue emission disappearing after heating at 500 C, and the orange emission disappearing after heating at different temperatures starting from 230 C, although sometimes it is stable up to 500 C in different samples. Both centers have spectral-kinetic properties very unusual for mineral luminescence, which in combination with extremely low impurity concentrations, prevent their identification with specific impurity related emission. The most likely explanation of these observations may be the presence of radiation-induced luminescence centers. The long violet afterglow is evidently connected with trapped charge carrier liberation, with their subsequent migration through the valence band and ultimate recombination with a radiation-induced center responsible for the unusual violet luminescence.

Comparison of the luminescent properties of Lu3Al5O12:Pr crystals and films under synchrotron radiation excitation

International Nuclear Information System (INIS)

Zorenko, Yu.; Gorbenko, V.; Zorenko, T.; Voznyak, T.; Nizankovskiy, S.

2016-01-01

The work is dedicated to comparative investigation of the luminescent properties of Lu 3 Al 5 O 12 :Pr(LuAG:Pr) single crystals and single crystalline films using excitation by synchrotron radiation with an energy of 3.7–25 eV in the exciton range of LuAG host. We have found that the differences in the excitation spectra and luminescence decay kinetics of LuAG:Pr crystals and films are caused by involving the LuAl antisite defects and oxygen vacancies in the crystals and Pb 2+ flux related dopants in the films in the excitation processes of the Pr 3+ luminescence. Taking into account these differences, we have determined the energy structure of the Pr 3+ ions in LuAG host and estimated the differences in the energies of creation of excitons bound with the isolated Pr 3+ ions in LuAG:Pr films and the dipole Pr–LuAl antisite defect centers in the crystal counterpart. - Highlights: • Comparison of the luminescent properties of LuAG:Pr single crystals and films. • Superposition of the Pr 3+ and defect centers luminescence of LuAG:Pr crystal. • Different creation energies of an excitons bound with the Pr 3+ in LuAG:Pr crystals and films. • More faster decay kinetics of the Pr 3+ luminescence in LuAG:Pr films. • Low content of slow emission component in LuAG:Pr films.

Temperature-dependent luminescence and temperature-stimulated NIR-to-VIS up-conversion in Nd3+-doped La2O3-Na2O-ZnO-TeO2 glasses

Science.gov (United States)

Sobczyk, Marcin

2013-04-01

Telluride glasses of the composition xNd2O3-(7-x)La2O3-3Na2O-25ZnO-65TeO2, where (0≤x≤7) were prepared by the melt quench technique. Some physical and optical properties of the glasses were evaluated. The thermal behavior i.e. glass transition and crystallization temperatures were studied by using TGA-DTA technique. Optical properties of Nd3+-doped telluride glasses were investigated between 298 and 700 K. Basing on the obtained values of J-O parameter values (×10-20 cm2: Ω2=4.49±0.84, Ω4=5.03±0.61, Ω6=4.31±0.73), the radiative transition probabilities (AT), radiative lifetimes (τR), fluorescence branching ratios (β) and emission cross-sections (σem) were calculated for the 4F3/2→4IJ/2 (where J=9, 11 and 13) transitions of Nd3+ ions. The τR value of the 4F3/2 level amount to 164 μs and is slightly higher than the measured decay time of 162 μs. With the increasing of Nd2O3 concentration from 0.5 to 7.0 mol% the experimental lifetime of the fluorescent level decreases from 162 to 5.6 μs. The estimated quantum efficiency amount to 100%, based on a comparison of τR and the experimental decay time of a slightly doped Nd3+ telluride glass. An analysis of the non-radiative decay was based on the cross-relaxation mechanisms. The 4F3/2→4I9/2 and 4F5/2→4I9/2 transitions were analyzed with respect to the fluorescence intensity ratio (FIR) and were found to be temperature dependent. Infrared-to-visible up-conversion emissions with a maximum at 603.0 and 635.3 nm were observed at high temperatures using the 804 nm excitation and are due to the 4G5/2→4I9/2 and 4G5/2→4I11/2 transitions of Nd3+ ions, respectively. The near quadratic dependence of fluorescence on excitation laser power confirms that two photons contribute to up-conversion of the orange emissions. The temperature-stimulated up-conversion excitation processes have been analyzed in detail. The optical results indicate that the investigated glasses are potentially applicable as a 1063 nm

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

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

Luminescent and scintillation properties of the Ce3+ doped Y3−xLuxAl5O12:Ce single crystalline films

International Nuclear Information System (INIS)

Zorenko, Yu.; Gorbenko, V.; Zorenko, T.; Popielarski, P.; Mosińska, L.; Fedorov, A.

2016-01-01

The work is related to the investigation of scintillation and luminescent properties of single crystalline films (SCF) of solid solutions of Ce 3+ doped Y 3−x Lu x Al 5 O 12 :Ce garnets with x value in the 0–3 range. We have shown a possibility of realization of high-energy shift of the Ce 3+ ion emission spectrum in these garnets up to 22 nm. We have also found that the light yield of the radioluminescence under α-particle excitation of LuAG:Ce SCF can exceed by 1.3 times the corresponding values for the YAG:Ce SCF counterpart. For investigation of the luminescent properties of Y 3−x Lu x Al 5 O 12 :Ce SCF at different x values the luminescent spectroscopy of these SCFs under excitation by synchrotron radiation in the VUV range was performed. - Highlights: • Single crystalline films of Y 3−x Lu x Al 5 O 12 garnets at x=0–3.0 were grown by LPE method onto YAG substrates. • Lattice constant of Y 3−x Lu x Al 5 O 12 :Ce film and the film/substrate misfit changed linearly with increasing of Lu content in the x=0–3.0 range. • High-energy shift of the Ce 3+ emission up to 22 nm in Y 3−x Lu x Al 5 O 12 film with increasing of Lu content in the x=0–3.0 range. • Light yield of Y 3−x Lu x Al 5 O 12 :Ce film decreases in the x=0–1.8 range and increases in the x=1.8–3.0 range. • Scintillation LY of Lu 3 Al 5 O 12 :Ce film can exceed by 1.3 times the LY for YAG:Ce film counterpart.

Enhanced performance of dye-sensitized solar cells based on TiO{sub 2} with NIR-absorption and visible upconversion luminescence

Energy Technology Data Exchange (ETDEWEB)

Liang, Li [Department of Chemistry, Harbin Institute of Technology, Harbin 150001 (China); Yulin, Yang, E-mail: ylyang@hit.edu.cn [Department of Chemistry, Harbin Institute of Technology, Harbin 150001 (China); Mi, Zhou; Ruiqing, Fan; LeLe, Qiu [Department of Chemistry, Harbin Institute of Technology, Harbin 150001 (China); Xin, Wang [Department of Chemistry, Harbin Institute of Technology, Harbin 150001 (China); Department of Food and Environmental Engineering, Heilongjiang, East University, Harbin 150086 (China); Lingyun, Zhang [Department of Chemistry, Harbin Institute of Technology, Harbin 150001 (China); School of Chemical Engineering, Northeast Dianli University, Jilin 132012 (China); Xuesong, Zhou; Jianglong, He [Department of Chemistry, Harbin Institute of Technology, Harbin 150001 (China)

2013-02-15

TiO{sub 2} with NIR-absorption and visible upconversion luminescence (UC-TiO{sub 2}) is prepared by a sol-gel method and calcined at 700 Degree-Sign C for 6 h. The material broadens the response region of dye sensitized solar cells (DSSCs) from an ultraviolet-visible region to the whole region of the solar spectrum. It shifts NIR sunlight to visible light which matches the strong absorbing region of the dye (N719). DSSCs based on UC-TiO{sub 2} achieved higher conversion efficiency than that on raw TiO{sub 2}. UC-TiO{sub 2} was mixed with commercial raw TiO{sub 2} as additive, and the short-circuit current density, open-circuit voltage and conversion efficiency of the DSSC reached to the optimum values 13.38 mA/cm{sup 2}, 0.78 V and 6.63% (AM1.5 global), comparing with the blank values: 7.99 mA/cm{sup 2}, 0.75 V and 4.07%, respectively. Also the mechanisms of upconversion by multiphoton absorption and energy transfer processes are interpreted in this paper. - Graphical abstract: By introducing TiO{sub 2} with NIR-absorption and visible up-conversion luminescence into DSSC, a signal reflection was explored from ultra-violet region to visible region, and to near-IR region. Highlights: Black-Right-Pointing-Pointer TiO{sub 2} with NIR-absorption and visible up-conversion luminescence (UC-TiO{sub 2}) was prepared by a sol-gel method. Black-Right-Pointing-Pointer A systematic characterization and analysis was carried out to discuss the mechanism. Black-Right-Pointing-Pointer A significantly enhanced performance of DSSC was explored by using UC-TiO{sub 2} as an additive.

Luminescent properties of BaCl2-Eu microcrystals embedded in a CsI matrix

International Nuclear Information System (INIS)

Pushak, A.; Vistovskyy, V.; Voloshinovskii, A.; Savchyn, P.; Antonyak, O.; Demkiv, T.; Dacyuk, Yu.; Myagkota, S.; Gektin, A.

2013-01-01

The spectral-luminescent properties of CsI-BaCl 2 (1 mol%)-Eu(0.02 mol%) crystalline system are studied. Europium ion doped BaCl 2 microcrystals embedded in a CsI matrix are revealed on CsI-BaCl 2 (1 mol%)-Eu(0.02 mol%) freshly cleaved surface by the scanning electron microscopy. The size of microcrystals is shown to be within 0.5–5 microns. The luminescent parameters of the BaCl 2 -Eu 2+ microcrystals are shown to be similar to ones of a single crystal analogue. The 4f → 5d absorption transitions in europium ions and the reabsorption of the intrinsic emission of the CsI host are the main excitation mechanisms of europium luminescence in the BaCl 2 microcrystals. -- Highlights: ► The formation of chloride BaCl 2 :Eu microcrystals in the case of BaCl 2 doped CsI crystal has been revealed. ► The observed size of microcrystals at BaCl 2 concentration of 1% is about 0.5–5 μm. ► Majority of Eu 2+ ions in CsI-BaCl 2 -EuCl 3 crystalline system enters into BaCl 2 microcrystals. ► The luminescent parameters of the BaCl 2 :Eu 2+ microcrystals and its bulk analogue are similar

Luminescence properties of the Sm-doped borate glasses

International Nuclear Information System (INIS)

Kindrat, I.I.; Padlyak, B.V.; Drzewiecki, A.

2015-01-01

The optical absorption and photoluminescence (emission and excitation) spectra as well as decay kinetics of a series of the Sm-doped glasses with Li 2 B 4 O 7 , LiKB 4 O 7 , CaB 4 O 7 , and LiCaBO 3 compositions were investigated and analysed. The Li 2 B 4 O 7 :Sm, LiKB 4 O 7 :Sm, CaB 4 O 7 :Sm, and LiCaBO 3 :Sm glasses of high optical quality have been obtained from the corresponding polycrystalline compounds in the air atmosphere, using a standard glass technology. On the basis of electron paramagnetic resonance (EPR) and optical spectra analysis it was shown that the samarium impurity is incorporated into the glass network as Sm 3+ (4f 5 , 6 H 5/2 ) ions, exclusively. All observed 4f – 4f transitions of the Sm 3+ centres in the optical absorption and luminescence spectra of the investigated glasses are identified. Most intense emission band of the Sm 3+ ions peaked about 598 nm ( 4 G 5/2 → 6 H 7/2 transition) is characterised by a single exponential decay with typical lifetime values, which depend on the basic glass composition as well as concentration and local structure of the Sm 3+ luminescence centres. The quantum efficiency has been evaluated for observed transitions of the Sm 3+ centres using obtained experimental lifetimes and radiative lifetimes calculated by Judd–Ofelt theory. The calculated high quantum efficiencies and measured quantum yields of luminescence show that the investigated borate glasses are perspective luminescence materials. Energy transfer from the Ce 3+ non-controlled impurity and intrinsic luminescence centres to the Sm 3+ centres has been observed. Peculiarities of the Sm 3+ local structure in the network of investigated glasses have been discussed based on the obtained spectroscopic results and structural data. - Highlights: • The Sm-doped Li 2 B 4 O 7 , LiKB 4 O 7 , CaB 4 O 7 , and LiCaBO 3 glasses of high quality were obtained. • EPR, optical absorption and luminescence spectra of Sm 3+ ions in obtained glasses were

Growth and luminescence properties of Pr3+-doped single crystalline films of garnets and perovskites

International Nuclear Information System (INIS)

Gorbenko, V.; Zorenko, Yu.; Savchyn, V.; Zorenko, T.; Pedan, A.; Shkliarskyi, V.

2010-01-01

Peculiarities of growth of single crystalline films (SCF) of Pr 3+ doped Y 3 Al 5 O 12 and Lu 3 Al 5 O 12 garnets and YAlO 3 and LuAlO 3 perovskites by the liquid phase epitaxy method from melt-solutions based on PbO-B 2 O 3 flux as well as luminescent and scintillation properties of these SCFs were studied in this work. Dependence the intensity of the Pr 3+ d-f and f-f-luminescence on the activator concentration and influence of Pb 2+ flux dopant on the light yield of SCFs of the mentioned garnets and perovskites were analyzed.

Zero-reabsorption doped-nanocrystal luminescent solar concentrators.

Science.gov (United States)

Erickson, Christian S; Bradshaw, Liam R; McDowall, Stephen; Gilbertson, John D; Gamelin, Daniel R; Patrick, David L

2014-04-22

Optical concentration can lower the cost of solar energy conversion by reducing photovoltaic cell area and increasing photovoltaic efficiency. Luminescent solar concentrators offer an attractive approach to combined spectral and spatial concentration of both specular and diffuse light without tracking, but they have been plagued by luminophore self-absorption losses when employed on practical size scales. Here, we introduce doped semiconductor nanocrystals as a new class of phosphors for use in luminescent solar concentrators. In proof-of-concept experiments, visibly transparent, ultraviolet-selective luminescent solar concentrators have been prepared using colloidal Mn(2+)-doped ZnSe nanocrystals that show no luminescence reabsorption. Optical quantum efficiencies of 37% are measured, yielding a maximum projected energy concentration of ∼6× and flux gain for a-Si photovoltaics of 15.6 in the large-area limit, for the first time bounded not by luminophore self-absorption but by the transparency of the waveguide itself. Future directions in the use of colloidal doped nanocrystals as robust, processable spectrum-shifting phosphors for luminescent solar concentration on the large scales required for practical application of this technology are discussed.

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.

Violet and visible up-conversion emission in Yb{sup 3+}-Ho{sup 3+} co-doped germanium-borate glasses

Energy Technology Data Exchange (ETDEWEB)

Yang Yanmin, E-mail: mihuyym@163.co [College of Physics Science and Technology, Hebei University, Baoding 071002 (China); Zhang Meixin [Forensic Science Lab, Hebei University, Baoding 071002 (China); Yang Zhiping [College of Physics Science and Technology, Hebei University, Baoding 071002 (China); Fu Zuoling [Key Laboratory of Coherent Light, Atomic and Molecular Spectroscopy, College of physics, Jilin University, Ministry of Education, Changchun 130023 (China)

2010-10-15

The up-conversion emission properties of Yb{sup 3+}-Ho{sup 3+} co-doped germanium-borate glasses have been investigated with 980 nm excitation. The violet, blue, green and red emission bands at about 350, 485, 544 and 653 nm can be identified, respectively. Experimental results indicated that the relative intensity ratios of the peaks I{sub Red}/I{sub Green} increased with increasing B{sub 2}O{sub 3} concentration, which led to changing color of up-conversion emission from green at x=0 to yellow at x=40, to red at x=60. The violet emission at 350 nm was first reported in germanium-borate glass host and up-conversion mechanisms of the emissions were discussed. The Yb{sup 3+}-Ho{sup 3+} co-doped germanium-borate glasses could be an alternative for the generation of violet and primary colors for application in solid-state displays.

Luminescent properties of Y{sub 3}Al{sub 5−x}Ga{sub x}O{sub 12}:Ce crystals

Energy Technology Data Exchange (ETDEWEB)

Zorenko, Yu., E-mail: zorenko@ukw.edu.pl [Institute of Physics, Kazimierz Wielki University in Bydgoszcz, Powstańców Wielkopolskich No 2, 85-090 Bydgoszcz (Poland); Zorenko, T. [Institute of Physics, Kazimierz Wielki University in Bydgoszcz, Powstańców Wielkopolskich No 2, 85-090 Bydgoszcz (Poland); Department of Electronics, Ivan Franko National University of Lviv, Gen. Tarnavskyj str. 107, 70017 Lviv (Ukraine); Malinowski, P. [Institute of Physics, Kazimierz Wielki University in Bydgoszcz, Powstańców Wielkopolskich No 2, 85-090 Bydgoszcz (Poland); Sidletskiy, O.; Neicheva, S. [Institute for Scintillation Materials, National Academy of Sciences of Ukraine, Lenina pr. 60, 61001 Kharkiv (Ukraine)

2014-12-15

Absorption, luminescent and scintillation properties of Ce{sup 3+} doped Y{sub 3}Al{sub 5−x}Ga{sub x}O{sub 12} crystals with Ga content in the x=1–5 range were investigated in this work and compared with the properties of YAG:Ce crystals. Apart from the traditional spectral methods (absorption, cathodoluminescence and light yield measurements), the intrinsic and Ce{sup 3+} related luminescence of Y{sub 3}Al{sub 5−x}Ga{sub x}O{sub 12}:Ce solid-solution were also investigated using the luminescent spectroscopy under excitation by synchrotron radiation in the 3.7–25 eV range. We show that the optical properties Y{sub 3}Al{sub 5−x}Ga{sub x}O{sub 12}:Ce garnets monotonically change with increasing the Ga content in the x=0–3 range due to preferable localization of Ga ions in the tetrahedral position of the garnet lattice. At the highest Ga concentration (x>3) the deviation of the optical properties of Y{sub 3}Al{sub 5−x}Ga{sub x}O{sub 12}:Ce garnets is observed from the respective properties of these crystals with Ga content in the x=0–3 range due to occupation by Ga ions of the octahedral position in the garnet host. - Highlights: • Different dependence of optical properties of Y{sub 3}Al{sub 5−x}Ga{sub x}O{sub 12}:Ce crystals on Ga content in x=0–3 and 3–5 ranges. • Elimination of the luminescence of Y{sub Al} antisite defects in Y{sub 3}Al{sub 5−x}Ga{sub x}O{sub 12}:Ce crystals at x>2. • Significant improvement of the scintillation properties of Y{sub 3}Al{sub 5−x}Ga{sub x}O{sub 12}:Ce crystals at x=2 and 3 in comparison with YAG:Ce.

Preparation and luminescence properties of Eu{sup 2+}doped {gamma}-aluminum oxynitride transparent ceramics

Energy Technology Data Exchange (ETDEWEB)

Zhang, Fang; Yuan, Xianyuan; Wang, Shaohua [Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai (China); Wang, Shiwei, E-mail: swwang51@mail.sic.ac.cn [Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai (China)

2013-01-15

Eu{sup 2+} doped {gamma}-AlON transparent ceramics have been prepared by the solid-state reaction sintering method. The influences of Eu concentration on both strength, transparency and luminescence properties of the as-prepared samples were discussed. The strength and transparency decreased as Eu content increased. Two bands were observed in the emission spectrum of each sample. One (B{sub 1}) was narrow and centered at around 401 nm, the other (B{sub 2}) was comparatively broader, and the location of its center as well as the intensity ratio of peak values of B{sub 2} to that of B{sub 1} varied with Eu content. - Highlights: Black-Right-Pointing-Pointer Eu{sub 2}O{sub 3} was an effective sintering aid in fabrication of transparent {gamma}-AlON ceramics. Black-Right-Pointing-Pointer Eu-doped transparent {gamma}-AlON ceramics exhibited broad emission spectra composed of two bands. Black-Right-Pointing-Pointer The relationship between crystal position of Eu{sup 2+} ions and luminescent properties was given.

Luminescence properties of copper(I), zinc(II) and cadmium(II) coordination compounds with picoline ligands

Energy Technology Data Exchange (ETDEWEB)

Małecki, Jan Grzegorz, E-mail: gmalecki@us.edu.pl; Maroń, Anna

2017-06-15

Mononuclear coordination compounds of copper(I) – [Cu(PPh{sub 3}){sub 2}(picoline)(NO{sub 3})], zinc(II) – [ZnCl{sub 2}(picoline){sub 2}] (picoline=3– and 4–methylpyridine) and polymeric cadmium(II) – [CdCl{sub 2}(β-picoline){sub 2}]{sub n} were prepared and their luminescence properties in solid state and acetonitrile solutions were determined. Single crystal X-ray crystallography revealed distorted tetrahedral geometry around the central ions of the compounds. The compounds exhibit green photoluminescence in solid state and in acetonitrile solutions. The emission of copper(I) compounds originated from metal-to-ligand charge transfer state combined with nitrato-to-picoline charge transfer state i.e. ({sup 1}(M+X)LCT). The presence of nitrato ligand in the coordination sphere of copper(I) compounds quenches the emission. Luminescence of zinc(II) and cadmium(II) compounds results from chloride-to-picoline charge transfer state and the quantum efficiency in the case of the polymeric Cd(II) compound reaches 39%. The photoluminescence quantum yields of the mononuclear zinc(II) compounds vary from 10 to 16% depending on the conditions (solid state, solution). - Graphical abstract: Coordination compounds of copper(I), zinc(II) and polymeric cadmium(II) with picoline ligands were prepared and their luminescence properties in solid state and acetonitrile solutions were determined. The compounds exhibit green photoluminescence in solid state and in acetonitrile solutions. Emission of copper(I) compounds originated from {sup 1}(M+X)LCT state. Luminescence of zinc(II) and cadmium(II) compounds results from chloride-to-picoline charge transfer state and the quantum efficiency in the case of the polymeric Cd(II) compound reaches 39%. The photoluminescence quantum yields of the mononuclear zinc(II) compounds vary from 10 to 16% depending on the conditions (solid state, solution).

Luminescence properties of the Sm-doped borate glasses

Energy Technology Data Exchange (ETDEWEB)

Kindrat, I.I. [University of Zielona Góra, Institute of Physics, Division of Spectroscopy of Functional Materials, 4a Szafrana Street, 65-516 Zielona Góra (Poland); Padlyak, B.V., E-mail: B.Padlyak@if.uz.zgora.pl [University of Zielona Góra, Institute of Physics, Division of Spectroscopy of Functional Materials, 4a Szafrana Street, 65-516 Zielona Góra (Poland); Vlokh Institute of Physical Optics, 23 Dragomanov Street, 79-005 Lviv (Ukraine); Drzewiecki, A. [University of Zielona Góra, Institute of Physics, Division of Spectroscopy of Functional Materials, 4a Szafrana Street, 65-516 Zielona Góra (Poland)

2015-10-15

The optical absorption and photoluminescence (emission and excitation) spectra as well as decay kinetics of a series of the Sm-doped glasses with Li{sub 2}B{sub 4}O{sub 7}, LiKB{sub 4}O{sub 7}, CaB{sub 4}O{sub 7}, and LiCaBO{sub 3} compositions were investigated and analysed. The Li{sub 2}B{sub 4}O{sub 7}:Sm, LiKB{sub 4}O{sub 7}:Sm, CaB{sub 4}O{sub 7}:Sm, and LiCaBO{sub 3}:Sm glasses of high optical quality have been obtained from the corresponding polycrystalline compounds in the air atmosphere, using a standard glass technology. On the basis of electron paramagnetic resonance (EPR) and optical spectra analysis it was shown that the samarium impurity is incorporated into the glass network as Sm{sup 3+} (4f{sup 5}, {sup 6}H{sub 5/2}) ions, exclusively. All observed 4f – 4f transitions of the Sm{sup 3+} centres in the optical absorption and luminescence spectra of the investigated glasses are identified. Most intense emission band of the Sm{sup 3+} ions peaked about 598 nm ({sup 4}G{sub 5/2} → {sup 6}H{sub 7/2} transition) is characterised by a single exponential decay with typical lifetime values, which depend on the basic glass composition as well as concentration and local structure of the Sm{sup 3+} luminescence centres. The quantum efficiency has been evaluated for observed transitions of the Sm{sup 3+} centres using obtained experimental lifetimes and radiative lifetimes calculated by Judd–Ofelt theory. The calculated high quantum efficiencies and measured quantum yields of luminescence show that the investigated borate glasses are perspective luminescence materials. Energy transfer from the Ce{sup 3+} non-controlled impurity and intrinsic luminescence centres to the Sm{sup 3+} centres has been observed. Peculiarities of the Sm{sup 3+} local structure in the network of investigated glasses have been discussed based on the obtained spectroscopic results and structural data. - Highlights: • The Sm-doped Li{sub 2}B{sub 4}O{sub 7}, LiKB{sub 4}O{sub 7}, Ca

Luminescent properties of CaTiO3:Pr thin-film phosphor deposited on ZnO/ITO/glass substrate

International Nuclear Information System (INIS)

Chung, Sung Mook; Han, Sang Hyuk; Song, Kuk Hyun; Kim, Eung Soo; Kim, Young Jin

2005-01-01

Red-emitting CaTiO 3 :Pr phosphor thin films were deposited on glass, ZnO/ITO/glass, and ITO/glass substrates by RF magnetron sputtering. The effects of various substrates and heat treatment on the structural and luminous properties were investigated. The films deposited on ZnO/ITO/glass exhibited superior crystallinity and more enhanced PL and CL properties compared with those on ITO/glass. The intermediate ZnO layer between phosphor film and ITO contributed to the growing behaviors and the roughening of CaTiO 3 :Pr phosphor thin films, and consequently, to the excellent luminescence. The luminescent properties of the films were improved by following heat-treatment due to a combination of factors, namely the transformation from amorphous to poly crystalline phases, the activation of the activators, and the elimination of microdefects

Characterization and luminescent properties of Eu{sup 3+} doped Gd{sub 2}Zr{sub 2}O{sub 7} nanopowders

Energy Technology Data Exchange (ETDEWEB)

Rabasovic, M.S., E-mail: majap@ipb.ac.rs [Institute of Physics, University of Belgrade (Serbia); Sevic, D. [Institute of Physics, University of Belgrade (Serbia); Krizan, J. [Faculty for Mechanical Engineering, University of Ljubljana (Slovenia); Terzic, M. [Faculty of Science, University of Novi Sad (Serbia); Mozina, J. [Faculty for Mechanical Engineering, University of Ljubljana (Slovenia); Marinkovic, B.P.; Savic-Sevic, S. [Institute of Physics, University of Belgrade (Serbia); Mitric, M. [Vinča Institute of Nuclear Science, University of Belgrade, P.O. Box 522, 11001 Belgrade (Serbia); Rabasovic, M.D.; Romcevic, N. [Institute of Physics, University of Belgrade (Serbia)

2015-02-15

Highlights: • Nanopowders Gd{sub 2}Zr{sub 2}O{sub 7} doped by europium ions (Eu{sup 3+}) have been synthesized. • Their luminescence properties have been measured at room temperature. • The temporal evolution of laser induced phenomena are presented using time-resolved technique. • Lifetime analysis for luminescence bands in emission spectra has been done. - Abstract: Nanopowders based on gadolinium zirconium oxide (Gd{sub 2}Zr{sub 2}O{sub 7}) doped by europium ions (Eu{sup 3+}) were successfully prepared using a flame combustion method. This material is suitable for various optical devices. The structure of prepared materials has been confirmed and characterized using X-ray powder diffraction (XRD), scanning electron microscope (SEM) and photoluminescence (PL) techniques. The luminescence properties of synthesized nanopowders were characterized by emission spectra and luminescence lifetimes by using the streak camera system. PL spectra were obtained at three different excitation wavelengths (Optical Parametric Oscilator (OPO) at 360 nm, laser diode at 365 nm and Ar laser line at 514.5 nm). The strong emission lines at 611 nm and 630 nm corresponding to the {sup 5}D{sub 0} → {sup 7}F{sub 2} long lived transition could be used as a new red light source in optical devices.

Luminescent properties of the potassium zinc phosphates of composition K1-xTlxZn(PO3)3

International Nuclear Information System (INIS)

El Abiad, A.; Mesnaoui, M.; Maazaz, M.; Parent, C.; Le Flem, G.

2003-01-01

Crystalline and glassy K 1-x Tl x Zn(PO 3 ) 3 polyphosphates have been synthesized and characterized. UV-visible spectroscopy was systematically used in order to analyze the optical properties of Tl + ions both in crystalline and glassy forms with the similar compositions. The investigated polyphosphates can be considered as a model system since the spectroscopic properties of Tl + ions in the glasses could be deduced by comparison with those in crystals. From structural point of view, in the crystalline forms the thallium ions are six-fold coordinated in a dissymmetrical oxygenated sites. Three luminescences (α, A X , A T ) have been then observed and were attributed to the isolated Tl + ions. In the glassy forms, an additional luminescence (D) has been detected in the low-energy range and was assigned to the Tl + pairs formation. The relationship between the Tl + site symmetry and its optical properties is discussed in the context of the Fukuda's model

Hydrothermal synthesis and upconversion luminescent properties of YVO4:Yb3+,Er3+ nanoparticles

International Nuclear Information System (INIS)

Liang, Yanjie; Chui, Pengfei; Sun, Xiaoning; Zhao, Yan; Cheng, Fuming; Sun, Kangning

2013-01-01

Graphical abstract: YVO 4 :Yb 3+ ,Er 3+ nanoparticles have been successfully prepared via a facile hydrothermal technique in the presence of citric acid as a complexing agent followed by a subsequent heat treatment process. The PL intensity of the sample increases with the increase of annealing temperature and excitation power. Under the excitation of a 980 nm diode laser, the samples show bright green luminescence. Highlights: ► YVO 4 :Yb 3+ ,Er 3+ nanoparticles were prepared by a hydrothermal approach. ► Bright green luminescence is observed under the excitation of a 980 nm laser diode. ► The PL intensity increases with the increase of annealing temperature. ► Energy transfer properties between Yb 3+ ion and Er 3+ ion were analyzed. -- Abstract: In this paper, YVO 4 :Yb 3+ ,Er 3+ nanoparticles have been successfully prepared via a facile hydrothermal technique in the presence of citric acid as a complexing agent followed by a subsequent heat treatment process. The nanostructures, morphologies and upconversion luminescent properties of the as-prepared YVO 4 :Yb 3+ ,Er 3+ upconverting nanoparticles were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM) and photoluminescent (PL) spectra. XRD results indicate that all the diffraction peaks of samples can be well indexed to the tetragonal phase of YVO 4 . TEM images demonstrate that the samples synthesized hydrothermally consist of granular-like nanoparticles ranging in size from about 30 to 50 nm. After being calcined at 500–800 °C for 2 h, the grain sizes of nanoparticles increase slightly. Additionally, the as-prepared nanoparticles show bright green luminescence corresponding to the 2 H 11/2 → 4 I 15/2 and 4 S 3/2 → 4 I 15/2 transitions of Er 3+ ions under the excitation of a 980 nm diode laser, which might find potential applications in fields such as phosphor powders, infrared detection and display devices

Influence of silver and copper doping on luminescent properties of zinc-phosphate glasses after x-ray irradiation

Science.gov (United States)

Murashov, Alexander A.; Sidorov, Alexander I.; Shakhverdov, Teimur A.; Stolyarchuk, Maxim V.

2017-11-01

It is shown, experimentally, that in silver- and copper-containing zinc-phosphate glasses, metal molecular clusters are formed during the glass synthesis. X-ray irradiation of these glasses led to the considerable increase of its luminescence in visible spectral range. This effect is caused by the transformation of the charged metal molecular clusters into the neutral state. Luminescence and excitation spectra of the glass, doped with silver and copper simultaneously, change significantly in comparison with the spectra of glasses doped with one metal. The reason for this can be the formation of hybrid AgnCum molecular clusters. The computer simulation of the structure and optical properties of such clusters by the time-dependent density functional theory method is presented. It is shown that the optimal luminescent material for photonics application, in comparison with other studied materials, is glass, containing hybrid molecular clusters.

Spectroscopic and visible luminescence properties of rare earth ions in lead fluoroborate glasses

Energy Technology Data Exchange (ETDEWEB)

Anjaiah, G. [Department of Physics, Osmania University, Hyderabad 500007 (India); Nayab Rasool, SK. [Department of Physics, Sri Venkateswara University, Tirupati 517502 (India); Kistaiah, P., E-mail: pkistaiah@yahoo.com [Department of Physics, Osmania University, Hyderabad 500007 (India)

2015-03-15

The lanthanide doped lead lithium calcium zinc fluoroborate glasses (LLCZFB:Ln) of composition 20PbF{sub 2}+10Li{sub 2}O+5Cao+5ZnO+59B{sub 2}O{sub 3}+1Ln{sub 2}O{sub 3} (where Ln=Sm, Eu and Dy in mol%) were prepared by conventional melt quench technique. The amorphous nature of these glasses was confirmed by X-ray diffraction studies. The glass transition temperatures (T{sub g}) were studied by DSC analysis. The glass structure and spectroscopic properties were investigated using optical absorption, vibrational and fluorescence spectra. The FT-IR spectra and Raman spectra reveal the presence of BO{sub 3}, BO{sub 4} and non-bridging oxygen's. The Judd–Ofelt intensity parameters Ω{sub λ} (λ=2, 4, 6) were determined from the spectral intensities of absorption bands. These parameters were used to calculate the radiative parameters such as radiative transition probability (A{sub R}), radiative life time (τ{sub R}) and branching ratio (β{sub r}) for various excited luminescent states of rare earth ions. The visible emission spectra for different rare earth ions were recorded by exciting the samples at different wavelengths and the decay rates for the different rare earth ions were measured. Using the emission spectra, full width half maxima (FWFM), stimulated emission cross section (σ{sup E}{sub p}) were evaluated. The nature of decay profiles of {sup 4}F{sub 9/2}, {sup 4}G{sub 5/2} and {sup 5}D{sub 0} states of Dy, Sm and Eu ions respectively are analyzed. Comparison of luminescence features of these glasses and also with those reported for different glass hosts indicates that the LLCZFB:Dy glass has strong luminescence in the visible region. - Highlights: • LLCZFB:Ln glasses are prepared with Ln: Sm, Eu and Dy. • Glasses are characterized by XRD, FTIR, Raman, absorption and emission spectra. • J–O theory is used to calculate different radiative properties. • Green, yellow and red emissions are observed. • Glasses are useful for the development

Optical filtering and luminescence property of some molybdates prepared by combustion synthesis

Energy Technology Data Exchange (ETDEWEB)

Yadav, P. J., E-mail: yadav.pooja75@yahoo.in [Department of Electronics, RTM Nagpur University, Nagpur (India); Joshi, C. P. [Physics Department, RCOEM, Nagpur (India); Moharil, S. V., E-mail: svmoharil@yahoo.com [Physics Department, RTM Nagpur University, Nagpur (India)

2014-10-15

As an important class of lanthanide inorganic compounds, rare earth ions doped molybdates have gained much attention due to their attractive luminescence and structural properties, supporting various promising applications as phosphor materials in the fields such as white light-emitting diodes, optical fibers, biolabel, lasers, and so on. The molybdate family has promising trivalent cation conducting properties and most of the optical properties result from electron transitions of the 4f shell, which are greatly affected by the composition and structures of rare-earth compounds. In this paper we report the molybdate CaMoO{sub 4}:Eu{sup 3+} for red SSL and Bi{sub 1.4}Y{sub 0.6}MoO{sub 6}, Y{sub 6}MoO{sub 12} for optical filtering, prepared by one step combustion synthesis.

Luminescence properties of glaciofluvial sediments from the Bavarian Alpine Foreland

International Nuclear Information System (INIS)

Klasen, N.; Fiebig, M.; Preusser, F.; Radtke, U.

2006-01-01

Dose recovery tests highlight the variation of luminescence properties for samples from different sites and sediment sources within a region. It is hence necessary to adjust parameters of the single-aliquot regenerative dose protocol for different samples to ensure complete dose recovery. Bleaching experiments demonstrate an initially faster bleaching of the quartz optical signal compared to feldspar. However, complete resetting of the optical signal of both quartz and feldspar minerals occurred within approximately the same time. Moreover, samples from different sites show significant differences in bleaching characteristics. Investigations on thermal transfer point out that potential age overestimation due to charge transfer can apparently be neglected for the samples under consideration

Light up conversion effects in Erbium doped CaBi4Ti4O15 ceramics

International Nuclear Information System (INIS)

Bokolia, Renuka; Sreenivas, K.

2013-01-01

In recent years the rare earth doped bismuth layered structured ferroelectric (BLSF) compositions such as CaBi 4 Ti 4 O 15 , SrBi 4 Ti 4 O 15 and BaBi 4 Ti 4 O 15 ceramics have shown interesting light up-conversion emission effects. The observation of such novel effects has generated a lot of scientific interest, and there is a need to further improve their dielectric, piezoelectric and light up-conversion properties. In the present study, Erbium doped CaBi 4 Ti 4 O 15 (CBT), and SrBi 4 Ti 4 O 15 (SBT) ferroelectric ceramic have been prepared by the conventional solid state reaction method. Formation of single phase material is confirmed by X-Ray Diffraction (XRD), and changes occurring in the lattice parameters with Erbium dopant are analysed. Room temperature dielectric studies and ferroelectric studies will be discussed. (author)

Fingermark detection on non-porous and semi-porous surfaces using YVO4:Er,Yb luminescent upconverting particles.

Science.gov (United States)

Ma, Rongliang; Shimmon, Ronald; McDonagh, Andrew; Maynard, Philip; Lennard, Chris; Roux, Claude

2012-04-10

This article describes the use of an anti-Stokes luminescent material (upconverter), yttrium vanadate doped with ytterbium and erbium (YVO(4):Er,Yb), for the development of latent fingermarks on a range of non-porous surfaces. Anti-Stokes luminescent materials emit light at shorter wavelengths than the excitation wavelength. This property is unusual in both natural and artificial materials commonly found as exhibits in forensic science casework. As a result, fingermark detection techniques based on anti-Stokes luminescence are potentially extremely sensitive and selective. Latent fingermarks on non-luminescent and inherently luminescent substrates, including Australian polymer banknotes (a well-known 'difficult' surface), were developed with YVO(4):Er,Yb by dry powder and wet powder techniques. The effectiveness of YVO(4):Er,Yb for fingermark detection was compared with that of cyanoacrylate fuming and of sodium yttrium tetrafluoride doped with ytterbium and erbium (NaYF(4):Er,Yb). The results illustrate some benefit of luminescent up-converting phosphors over traditional luminescence techniques for the detection of latent fingermarks. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Luminescence in medical image science

Energy Technology Data Exchange (ETDEWEB)

Kandarakis, I.S., E-mail: kandarakis@teiath.gr

2016-01-15

Radiation detection in Medical Imaging is mostly based on the use of luminescent materials (scintillators and phosphors) coupled to optical sensors. Materials are employed in the form of granular screens, structured (needle-like) crystals and single crystal transparent blocks. Storage phosphors are also incorporated in some x-ray imaging plates. Description of detector performance is currently based on quality metrics, such as the Luminescence efficiency, the Modulation Transfer Function (MTF), the Noise Power Spectrum (NPS) and the Detective Quantum Efficiency (DQE) can be defined and evaluated. The aforementioned metrics are experimental evaluated for various materials in the form of screens. A software was designed (MINORE v1) to present image quality measurements in a graphical user interface (GUI) environment. Luminescence efficiency, signal and noise analysis are valuable tools for the evaluation of luminescent materials as candidates for medical imaging detectors. - Highlights: • Luminescence based medical imaging detectors. • Image science: MTF, NPS, DQE. • Phosphors screens light emission efficiency experimental evaluation. • Theoretical models for estimation of phosphor screen properties. • Software for medical image quality metrics.

Effect of annealing on structural and luminescence properties of Eu3+ doped NaYF4 phosphor

Science.gov (United States)

Pathak, Trilok K.; Kumar, Ashwini; Swart, H. C.; Kroon, R. E.

2018-04-01

Eu3+ doped NaYF4 phosphors have been synthesized by the combustion method. The effect of annealing on the structural, morphological and luminescence properties has been investigated. X-ray diffraction analysis revealed that the Eu3+ doped NaYF4 phosphors consisted of mixed phases: α-phase and β-phase which were affected by the annealing of the phosphor. The surface morphology showed a significant change with annealing in the Eu3+ doped NaYF4 phosphors. The elemental mapping and energy dispersive X-ray spectroscopy spectra proved the formation of the desired materials. The photoluminescence spectra illustrated the optical properties of Eu3+ in the as-prepared and annealed Eu3+ doped NaYF4 phosphors. The intensity of the peaks 5D0 → 7F2 and 5D0 → 7F1 varied in as-prepared and annealed samples. The lifetime of the Eu3+ luminescence at 615 nm was also weakly affected by the Eu3+ doping and annealing temperature.

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.

Synthesis, characterization and luminescent properties of lanthanide complexes with an unsymmetrical tripodal ligand

Energy Technology Data Exchange (ETDEWEB)

Yan Zhenzhong [State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000 (China); Tang Yu [State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000 (China)], E-mail: tangyu@lzu.edu.cn; Liu Weisheng; Tan Minyu [State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000 (China)

2008-09-15

Solid complexes of lanthanide nitrates with a new unsymmetrical tripodal ligand, bis[(2'-benzylaminoformyl)phenoxyl)ethyl](ethyl)amine (L) have been synthesized and characterized by elemental analysis, infrared spectra and molar conductivity measurements. At the same time, the luminescent properties of the Sm(III), Eu(III), Tb(III) and Dy(III) nitrate complexes in solid state were also investigated. Under the excitation of UV light, these complexes exhibited characteristic emission of central metal ions.

Recent Advances on Luminescent Enhancement-Based Porous Silicon Biosensors.

Science.gov (United States)

Jenie, S N Aisyiyah; Plush, Sally E; Voelcker, Nicolas H

2016-10-01

Luminescence-based detection paradigms have key advantages over other optical platforms such as absorbance, reflectance or interferometric based detection. However, autofluorescence, low quantum yield and lack of photostability of the fluorophore or emitting molecule are still performance-limiting factors. Recent research has shown the need for enhanced luminescence-based detection to overcome these drawbacks while at the same time improving the sensitivity, selectivity and reducing the detection limits of optical sensors and biosensors. Nanostructures have been reported to significantly improve the spectral properties of the emitting molecules. These structures offer unique electrical, optic and magnetic properties which may be used to tailor the surrounding electrical field of the emitter. Here, the main principles behind luminescence and luminescence enhancement-based detections are reviewed, with an emphasis on europium complexes as the emitting molecule. An overview of the optical porous silicon microcavity (pSiMC) as a biosensing platform and recent proof-of-concept examples on enhanced luminescence-based detection using pSiMCs are provided and discussed.

Luminescence and scintillation properties of LuPO4-Ce nanoparticles

International Nuclear Information System (INIS)

Vistovskyy, V.; Malyy, T.; Pushak, A.; Vas’kiv, A.; Shapoval, A.; Mitina, N.; Gektin, A.; Zaichenko, A.; Voloshinovskii, A.

2014-01-01

Study of the spectral-luminescence parameters of LuPO 4 -Ce nanoparticles upon the excitation by X-ray quanta and synchrotron radiation with photon energies of 4–25 eV was performed. Nanoparticles with mean size about a=35 nm and nanoparticles with size less than 12 nm reveal the different structures of cerium centers. Luminescence efficiency of LuPO 4 -Ce nanoparticles of a 4 -Ce nanoparticles studied using synchrotron and X-ray excitation. • Different structure of Ce 3+ -centers has been revealed for LuPO 4 -Ce nanoparticles. • Luminescence of LuPO 4 -Ce with size less than 12 nm is strongly quenched upon the X-ray excitation

Control of spontaneous emission rate in luminescent resonant diamond particles

Science.gov (United States)

Savelev, R.; Zalogina, A.; Kudryashov, S.; Ivanova, A.; Levchenko, A.; Makarov, S.; Zuev, D.; Shadrivov, I.

2018-01-01

We study the properties of luminescent diamond particles of different sizes (up to ~1.5 μm) containing multiple NV-centers. We theoretically predict that the average liftetime in such particles is decreased by several times as compared to optically small subwavelength nanodiamonds. In our experiments, samples were obtained by milling the plasma-enhanced chemical vapor deposited diamond film, and characterized by Raman spectroscopy and dark- field spectroscopy methods. Time-resolved luminescence measurements of the excited state of NV-centers showed that their average lifetime varies from 10 to 17 ns in different samples. By comparing this data to the values of the lifetime of the NV-centers in optically small nanodiamonds, known from literature, we confirm a severalfold decrease of the lifetime in resonant particles.

Structural and luminescence properties of europium(III)-doped zirconium carbonates and silica-supported Eu3+-doped zirconium carbonate nanoparticles

International Nuclear Information System (INIS)

Sivestrini, S.; Riello, P.; Freris, I.; Cristofori, D.; Enrichi, F.; Benedetti, A.

2010-01-01

The synthesis, morphology and luminescence properties of europium(III)-doped zirconium carbonates prepared as bulk materials and as silica-supported nanoparticles with differing calcination treatments are reported. Transmission electron microscopy and X-ray diffraction analyses have, respectively, been used to study the morphology and to quantify the atomic amount of europium present in the optically active phases of the variously prepared nanomaterials. Rietveld analysis was used to quantify the constituting phases and to determinate the europium content. Silica particles with an approximate size of 30 nm were coated with 2 nm carbonate nanoparticles, prepared in situ on the surface of the silica core. Luminescence measurements revealed the role of different preparation methods and of europium-doping quantities on the optical properties observed.

Dependence of the thermal influence on luminescence lifetimes from quartz on the duration of optical stimulation

International Nuclear Information System (INIS)

Chithambo, M.L.

2003-01-01

Time-resolved luminescence spectra may be measured from quartz at various stages of continuous optical stimulation in order to investigate properties of the spectra associated with the 'fast', 'medium', and 'slow' components of continuous optically stimulated luminescence (OSL). In this work, temperature related changes of luminescence lifetimes and luminescence intensity, both evaluated from time-resolved luminescence spectra recorded in the 'fast' 'medium' and 'slow' component regions of quartz OSL, have been investigated. The luminescence, stimulated at 525 nm, and measured at intervals between 20 deg. C and 200 deg. C reaches maximum intensity at 100 deg. C and decreases thereafter up to 200 deg. C, the maximum temperature of the investigations. Luminescence lifetimes, on the other hand, remain constant within 40±3 μs between 20 deg. C and 100 deg. C and then decrease down to about μs at 200 deg. C. The initial increase of luminescence intensity with temperature between 20 deg. C and 100 deg. C is discussed in terms of thermal assistance to luminescence stimulation. Beyond 100 deg. C, radiative recombination is affected by quenching of luminescence and reduction in luminescence lifetimes. The activation energy for thermal quenching was evaluated to be in the range 0.63±0.07 eV at all stimulation times and that of thermal assistance was evaluated to be about 0.06 eV for the 'fast' and 'medium' component regions and about 0.1 eV for the 'slow' component region of the OSL

Investigations of gamma irradiation on the properties of luminescent films of polycarbonate(PC) matrix doped with europium complex [Eu(tta)3(H2O)2

International Nuclear Information System (INIS)

Forster, Pedro L.; Lugao, Ademar B.; Martins, Natalia A.; Egute, Nayara S.; Parra, Duclerc F.; Brito, Hermi F.

2009-01-01

Luminescent lanthanide complexes have attracted much recent interest for their application as luminescent materials. The combination of unique spectroscopic properties from rare earth complexes associated to physical and chemical intrinsic properties of polymers became more attractive in the last years. A number of advantages of these substances have been reported or realized over the much studied conjugated polymers and nonlanthanide. Luminescent films composed by diaquatris(thenoyltrifluoroacetonate)europium(III) complex [Eu(tta) 3 (H 2 O) 2 ] doped into a polycarbonate (PC) matrix were prepared and irradiated at gamma radiation with 5, 10, and 20 kGy. The PC polymer was doped with 1% (w/w) of the Eu 3+ complex. The thermal properties was investigated by utilization of differential scanning calorimeter (DSC) changes in thermal stability was observed due to the addition of doping agent into the polycarbonate matrix. Changes in photophysical properties due of gamma radiation was observed by emission, excitation spectra and fourier transformed infrared spectra (FTIR). Based on the emission spectra of PC:1% Eu(tta)3 film were observed the characteristic bands arising from the 5 D 0 7 F J transitions of Eu 3+ ion (J=0-4), indicating the ability to obtain the luminescence films. (author)

Controlled synthesis of different multilayer architectures of GdBO{sub 3}:Eu{sup 3+} phosphors and shape-dependent luminescence properties

Energy Technology Data Exchange (ETDEWEB)

Leng, Zhihua; Zhang, Nannan; Liu, Yali; Li, Linlin; Gan, Shucai, E-mail: gansc@jlu.edu.cn

2015-03-01

Graphical abstract: - Highlights: • Pancake-like/flower-like/leaf-like GdBO{sub 3} were obtained via a hydrothermal method. • Gd(OH){sub 3} nanorods and borates were used as the precursors for the first time. • A dissolution and recrystallization process was happened induced by the excess borax. • Three products have the similar stacked arrangements to reduce the surface energy. • The luminescence properties of GdBO{sub 3}:Eu{sup 3+} are related to shape and crystallinity. - Abstract: Monodisperse pancake-like/flower-like/leaf-like GdBO{sub 3} samples have been successfully synthesized via a designed hydrothermal conversion method using H{sub 3}BO{sub 3}, Na{sub 2}B{sub 4}O{sub 7}·10H{sub 2}O, or NaBO{sub 2}·4H{sub 2}O as boron sources, respectively. It was found that different boron sources have crucial influences on the formation and morphology of the products. The Gd(OH){sub 3} nanorods precursors were prepared through a simple hydrothermal process, which then served as sacrificial templates for the fabrication of GdBO{sub 3} micropancakes/microflowers/microleaves via a hydrothermal conversion process. FT-IR spectra confirm that vaterite-type GdBO{sub 3} can be synthesized by this method. The possible formation mechanisms for different microstructures were put forward on the basis of a series of time-dependent control experiments. The products have similar stacked arrangements driven by the minimization of the interfacial and surface energy of the hydrothermal system. An investigation on the photoluminescence (PL) properties of GdBO{sub 3}:Eu{sup 3+} samples with different morphologies indicates that the PL properties of as-obtained GdBO{sub 3}:Eu{sup 3+} phosphors are strongly dependent on their morphology and crystallinity. The flower-like structure exhibits the strongest red emission.

Synthesis and luminescence properties of cinnamide based nanohybrid materials containing Eu (II) ions

Science.gov (United States)

Kiran Kumar, A. B. V.; Jayasimhadri, M.; Cha, Hyeongrae; Chen, Kuangcai; Lim, Jae-Min; Lee, Yong-Ill

2011-07-01

In the present work, the cinnamide based organic-inorganic hybrid luminescent materials were prepared by using sol-gel technique, in which both the components are covalently linked via Si-C bonds. The organic precursor N-(3-(triethoxysilyl)propyl)cinnamide (Cn-Si) was synthesized by (3-aminopropyl) triethoxysilane being reacted with cinnamoyal chloride. Finally, novel hybrid materials were prepared successfully through hydrolysis and polycondensation processes between the alkoxide groups of precursors Cn-Si and tetraethylorthosilane (TEOS) in the presence of europium nitrate. We have characterized thoroughly the prepared samples using FT-IR, thermal analysis (TGA/DTA), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), energy-dispersive spectroscopy (EDS) and photoluminescence (PL) spectroscopy. The results indicate that these materials exhibit the excellent thermal stability up to 350 °C. The X-ray diffraction patterns confirmed the amorphous nature of the developed materials. The rare-earth doped hybrid materials have exhibited an intense green emission at 530 nm with CIE chromaticity coordinates (0.4801, 0.4669). Whereas, the un-doped one gives some remarkable blue emission properties under UV excitation.

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)

Gadolinium oxysulfide nanoprobes with both persistent luminescent and magnetic properties for multimodal imaging

OpenAIRE

ROSTICHER , C.; Viana , Bruno; Fortin , M.-A.; Lagueux , J.; Faucher , L.; Chanéac , Corinne

2016-01-01

International audience; Persistent luminescence and magnetic properties of Gd2O2S: Eu 3+ , Ti 4+ , Mg 2+ nanoparticles have been studied to attest the relevance of such nanoparticles as nanoprobes for multimodal imaging. The development of new imaging tools is required to improve the quality of medical images and then to diagnose some disorders as quickly as possible in order to ensure more effective treatment. Multimodal imaging agents here developed combine the high resolution abilities of ...

Spectral-converting behaviors of Er{sup 3+} and Er{sup 3+}–Yb{sup 3+} doped YOCl phosphors

Energy Technology Data Exchange (ETDEWEB)

Park, Sangmoon, E-mail: spark@silla.ac.kr [Center for Green Fusion Technology and Department of Engineering in Energy and Applied Chemistry, Silla University, Busan 617-736 (Korea, Republic of); Cho, So-Hye [Center for Materials Architecturing, Institute of Multidisciplinary Convergence of Materials, Korea Institute of Science and Technology, Seoul 130-650 (Korea, Republic of)

2014-01-25

Highlights: • Luminescent materials of YOCl:Er,Yb were prepared using NH{sub 4}Cl flux. • Interesting spectral-converting behaviors were observed in the phosphors. • 980 or 1550 nm diode laser was irradiated for up-converting study. • A multi-photon process in the phosphors was calculated. -- Abstract: Luminescent materials composed of Y{sub 1−m−n}Er{sub m}Yb{sub n}OCl (m = 0.001–0.1, n = 0.005–0.1) were prepared via a solid-state reaction using NH{sub 4}Cl flux. Photoluminescence spectra, the dependence of the luminescent intensity as a function of Er{sup 3+} content, and their CIE coordinates of the Er{sup 3+}-doped layered YOCl compounds were also investigated under near-ultraviolet (NUV) and visible lights. The spectral up-converting properties of Er{sup 3+} and Er{sup 3+}–Yb{sup 3+} in YOCl phosphors were elucidated under 980 and 1550 nm diode laser irradiations. This up-conversion emission spectra and the pump power dependence versus emission intensity observed in the Y{sub 0.9}Er{sub 0.1}OCl up-conversion phosphors gave rise to one- and two-photon processes. The up-conversion mechanism of Er{sup 3+} and Yb{sup 3+} ions in YOCl was described by a schematic energy-level diagram. Through the use of these up-conversion luminescent materials, the desired emitting lights throughout the orange and red regions of the spectra were achieved.

Luminescence properties of oxide films formed by anodization of aluminum in 12-tungstophosphoric acid

International Nuclear Information System (INIS)

Stojadinovic, S.; Vasilic, R.; Petkovic, M.; Nedic, Z.; Kasalica, B.; Belca, I.; Zekovic, Lj.

2010-01-01

In this paper, we have investigated luminescence properties of oxide films formed by anodization of aluminum in 12-tungstophosphoric acid. For the first time we have measured weak luminescence during anodization of aluminum in this electrolyte (so-called galvanoluminescence GL) and showed that there are wide GL bands in the visible region of the spectrum and observed two dominant spectral peaks. The first one is at about 425 nm, and the second one shifts with anodization voltage. As the anodization voltage approaches the breakdown voltage, a large number of sparks appear superimposed on the anodic GL. Several intensive band peaks were observed under breakdown caused by electron transitions in W, P, Al, O, H atoms. Furthermore, photoluminescence (PL) of anodic oxide films and anodic-spark formed oxide coatings were performed. In both cases wide PL bands in the range from 320 nm to 600 nm were observed.

Langmuir–Blodgett films based on poly(p-phenylene vinylene) and protein-stabilised palladium nanoparticles: Implications in luminescent and conducting properties

Energy Technology Data Exchange (ETDEWEB)

Goto, Thiago E.; Sakai, Andrei [Institute of Environmental, Chemical and Pharmaceutical Sciences, Federal University of São Paulo, Diadema, SP 09972-270 (Brazil); Iost, Rodrigo M. [Institute of Chemistry of de São Carlos, University of São Paulo, São Carlos, SP 13560-970 (Brazil); Silva, Welter C. [Center of Nature Sciences, Federal University of Piauí, Teresina, PI 64049-550 (Brazil); Crespilho, Frank N. [Institute of Chemistry of de São Carlos, University of São Paulo, São Carlos, SP 13560-970 (Brazil); Péres, Laura O. [Institute of Environmental, Chemical and Pharmaceutical Sciences, Federal University of São Paulo, Diadema, SP 09972-270 (Brazil); Caseli, Luciano, E-mail: lcaseli@unifesp.br [Institute of Environmental, Chemical and Pharmaceutical Sciences, Federal University of São Paulo, Diadema, SP 09972-270 (Brazil)

2013-07-01

In this paper, poly(p-phenylene vinylene) block copolymers (PPV) were immobilised in stearic acid (HSt) Langmuir–Blodgett (LB) films, and their conducting and luminescent properties were enhanced by the incorporation of palladium nanoparticles stabilised by glucose oxidase (GOx-PdNPs). The nanobiocomposite, based on HSt, PPV, and GOx-PdNPs, was transferred from the air-water interface onto solid supports using the LB technique. The films were characterised by surface pressure–area isotherms, polarisation modulation infrared reflection–absorption spectroscopy, fluorescence spectroscopy, and conductivity measurements. The results indicated that the incorporation of GOx-PdNPs in PPV-HSt LB films enhances the luminescence and conducting properties of the PPV. Based on the higher conductivity and emission obtained with the hybrid LB films and the ability to tune the molecular-level interactions between the film components by changing the experimental conditions, thus allowing for further optimisation, one may envisage applications for these films in optical and electronic devices, such as organic light-emitting diodes. - Highlights: • Palladium nanoparticles were introduced in conducting polymer-fatty acid monolayers. • Hybrid films were characterised with tensiometry and infrared spectroscopy. • Films were transferred to solid supports with the Langmuir–Blodgett technique. • Nanoparticles enhanced luminescence and conducting properties.

The influence of silver-ion doping using ion implantation on the luminescence properties of Er–Yb silicate glasses

Energy Technology Data Exchange (ETDEWEB)

Stanek, S., E-mail: stanislav.stanek@vscht.cz [Department of Inorganic Chemistry, Faculty of Chemical Technology, University of Chemistry and Technology, Technicka 5, 16628 Prague (Czech Republic); Nekvindova, P.; Svecova, B.; Vytykacova, S.; Mika, M. [Department of Inorganic Chemistry, Faculty of Chemical Technology, University of Chemistry and Technology, Technicka 5, 16628 Prague (Czech Republic); Oswald, J. [Institute of Physics, Academy of Science of the Czech Republic, Cukrovarnicka 10/112, 162 00 Prague (Czech Republic); Mackova, A.; Malinsky, P. [Nuclear Physics Institute, Academy of Sciences of the Czech Republic, 25068 Rez (Czech Republic); Department of Physics, Faculty of Science, J.E. Purkinje University, Ceske mladeze 8, 40096 Usti nad Labem (Czech Republic); Spirkova, J. [Department of Inorganic Chemistry, Faculty of Chemical Technology, University of Chemistry and Technology, Technicka 5, 16628 Prague (Czech Republic)

2016-03-15

A set of zinc-silicate glasses with different ratios of erbium and ytterbium was fabricated. To achieve Ag-rich thin films in a sub-surface layer, ion-implantation technique at an energy of 1.2 MeV and 1.7 MeV with a fluence of 1 × 10{sup 16} cm{sup −2} was used. Post-implantation annealing was also applied. Changes in the spectroscopic and lasing properties of erbium ions as a function of implantation fluence of silver were studied with the aim to assess the positive effect of silver as a sensitiser of erbium luminescence. Therefore, absorption spectra in the visible range as well as luminescence spectra in the near-infrared range were measured and partially also the {sup 4}I{sub 11/2}–{sup 4}I{sub 15/2} transition of the erbium ion was studied. The results showed that silver positively influenced luminescence intensity at 1530 nm by increasing it almost three times. The biggest increase was achieved in glass with the highest concentration of erbium. Luminescence lifetime was not significantly influenced by the presence of silver and still remained around 10 ms.

Enhancing solar cell efficiency: the search for luminescent materials as spectral converters.

Science.gov (United States)

Huang, Xiaoyong; Han, Sanyang; Huang, Wei; Liu, Xiaogang

2013-01-07

Photovoltaic (PV) technologies for solar energy conversion represent promising routes to green and renewable energy generation. Despite relevant PV technologies being available for more than half a century, the production of solar energy remains costly, largely owing to low power conversion efficiencies of solar cells. The main difficulty in improving the efficiency of PV energy conversion lies in the spectral mismatch between the energy distribution of photons in the incident solar spectrum and the bandgap of a semiconductor material. In recent years, luminescent materials, which are capable of converting a broad spectrum of light into photons of a particular wavelength, have been synthesized and used to minimize the losses in the solar-cell-based energy conversion process. In this review, we will survey recent progress in the development of spectral converters, with a particular emphasis on lanthanide-based upconversion, quantum-cutting and down-shifting materials, for PV applications. In addition, we will also present technical challenges that arise in developing cost-effective high-performance solar cells based on these luminescent materials.

Luminescence characteristics of dental ceramics for retrospective dosimetry: a preliminary study

International Nuclear Information System (INIS)

Bailiff, I.K.; Correcher, V.; Delgado, A.; Goksu, Y.; Huebner, S.

2002-01-01

Ceramic materials that are widely employed in dental prosthetics and repairs exhibit luminescent properties. Because of their use in the body, these materials are potentially of interest in situations where retrospective dosimetry for individuals is required but where monitoring was not planned. The luminescent properties of dental ceramics obtained in Germany, Spain and the UK were examined. Linear dose-response characteristics were obtained in the range <100 mGy to 10 Gy using thermoluminescence (TL), optically stimulated luminescence and infrared-stimulated luminescence measurement techniques. Measurements of time-resolved luminescence were also performed to examine the nature of the luminescence recombination under visible (470 nm) and IR (855 nm) stimulation. The results obtained by TL and optically stimulated techniques suggest that there may be deeper traps than previously observed in certain types of dental ceramic. Such traps may be less susceptible to optical and athermal fading than was reported in earlier studies. (author)

Facile Template-Free Fabrication of the hollow sea cucumber-like TbF{sub 3} and luminescent properties

Energy Technology Data Exchange (ETDEWEB)

Gao, Yu, E-mail: gaoy777@126.com [College of Materials Science and Engineering, Shenyang University of Chemical Technology, Shenyang, 100142 (China); Shi, Shan; Fang, Qinghong; Yang, Feng [College of Materials Science and Engineering, Shenyang University of Chemical Technology, Shenyang, 100142 (China); Xu, Zhenhe [College of Applied Chemistry, Shenyang University of Chemical Technology, Shenyang, 100142 (China)

2014-12-15

Graphical abstract: Hollow sea cucumber-like TbF{sub 3} has been prepared via a facile hydrothermal route. The possible growth mechanism and the luminescent properties of the as-prepared sample have been discussed. - Highlights: • TbF3 particles were prepared by a facile hydrothermal route. • TbF3 product show strong green emission. • This method may be more widely applicable in the design of other rare-earth compounds. - Abstract: Hollow sea cucumber-like TbF{sub 3} was successfully fabricated by a self-assembled hydrothermal method. The crystal structure, morphology and photoluminescence properties of the as-prepared TbF{sub 3} crystals were investigated. The results revealed that the as-prepared TbF{sub 3} sample has orthorhombic structure and composed of monodispersed 3D hollow sea cucumber-like particles. The possible formation mechanism for sea cucumber-like TbF{sub 3} is presented in detail. Additionally, the as-prepared sample possesses property of down-conversion photoluminescence. The excitation spectrum of TbF{sub 3} sample was obtained by monitoring the emission of Tb{sup 3+} at 545 nm was composed of the characteristics f–f transition lines within the Tb{sup 3+} 4f{sup 8} configuration. Under the UV light irradiation, the emission spectrum exhibited four obvious lines centered at 491, 545, 588, and 620 nm, which was corresponding to the {sup 5}D{sub 4} → {sup 7}F{sub J} (J = 6, 5, 4, 3) transitions of the Tb{sup 3+} ions in the TbF{sub 3} nanoparticles.

Optically stimulated luminescence (OSL) and some other luminescence images from granite slices exposed with radiations

International Nuclear Information System (INIS)

Hashimoto, T.; Notoya, S.; Ojima, T.; Hoteida, M.

1995-01-01

Optically stimulated luminescence (OSL) images of some X- and γ-irradiated granite slices were obtained using photon detection through a 570 nm bandpass filter with diode-laser excitation of 910 nm. Alternative photo-induced phosphorescence (PIP) images, which were colour photographed immediately after the sunlight exposure of slice samples, were also found to be helpful in the observation of the luminescence properties and to filter selection for OSL measurements. These OSL and PIP images were compared with some other colour luminescence images, including thermoluminescence images (TLCI) and after-glow images (AGCI). It was obvious that there exists a variety of coloured emissions derived mainly from feldspar constituents and these were found to be dependent on the geological history or metamorphism of the granites. (Author)

Structural and luminescence properties of GaN nanowires grown using cobalt phthalocyanine as catalyst

Science.gov (United States)

Yadav, Shivesh; Rodríguez-Fernández, Carlos; de Lima, Mauricio M.; Cantarero, Andres; Dhar, Subhabrata

2015-12-01

Catalyst free methods have usually been employed to avoid any catalyst induced contamination for the synthesis of GaN nanowires with better transport and optical properties. Here, we have used a catalytic route to grow GaN nanowires, which show good optical quality. Structural and luminescence properties of GaN nanowires grown by vapor-liquid-solid technique using cobalt phthalocyanine as catalyst are systematically investigated as a function of various growth parameters such as the growth temperature and III/V ratio. The study reveals that most of the nanowires, which are several tens of microns long, grow along [ 10 1 ¯ 0 ] direction. Interestingly, the average wire diameter has been found to decrease with the increase in III/V ratio. It has also been observed that in these samples, defect related broad luminescence features, which are often present in GaN, are completely suppressed. At all temperatures, photoluminescence spectrum is found to be dominated only by a band edge feature, which comprises of free and bound excitonic transitions. Our study furthermore reveals that the bound excitonic feature is associated with excitons trapped in certain deep level defects, which result from the deficiency of nitrogen during growth. This transition has a strong coupling with the localized vibrational modes of the defects.

Redox reactions and mechanism of luminescence in BaFCl:Eu

CERN Document Server

Upadeo, S V; Gundurao, T K

1998-01-01

The phenomenon of stimulable luminescence of phosphors pre-irradiated with high-energy radiation is widely used in the field of imaging. Phosphors such as BaFX:Eu (X = Cl, Br) are extensively used in x-ray screens for digital image processing. There is, however, divided opinion regarding the mechanism responsible for the luminescence process in these materials. In this paper we have discussed the role of Eu sup 3 sup +reversible Eu sup 2 sup + conversion in BaFCl:Eu phosphor using PL, TL, TL emission and ESR techniques. (author)

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.

Retrospective individual dosimetry using luminescence and EPR after radiation accidents

International Nuclear Information System (INIS)

Goeksu, H.Y.; Wieser, A.; Ulanovsky, A.

2007-01-01

In areas where radiation dose monitoring has not been performed, it is essential to use material available in the environment be able to rapidly assess doses to individuals for immediate emergency medical care or for general estimation of the radiological consequences. It was shown that certain types of telephone cards containing microchips have the potential to be used as individual radiation dosimeters in emergency situations to detect doses over 250 mGy by luminescence measurements. In order to understand the dosimetric properties of chip cards, the components obtained from INFINIEON Company at various stages of production were used for luminescence measurements. It is found that the protecting layer used above the chips so called 'globe top' is the main source of radiation induced signal in chip cards. The globe top produced by INFINIEON at that stage is found to contain SiO2 and Epoxy. In order to improve the dosimetric properties of the chip cards, the raw material of the globe top is mixed with phosphorous material. The variation of the dose response and the detection limit with respect to the amount and the type of the phosphor added to the globe top is investigated using thermo luminescence (TL) and infrared stimulated luminescence (IRSL). Taking into account the rapid changes in chip card producing technology such as material properties, size of the globe top, a special-purpose software tool has been developed to calculate integral free-in-air kerma or organ dose for a given energy dose response of the card and irradiation conditions (photon fluence spectrum and irradiation geometry). It is also shown that adding phosphors powders such as Al2O3:C, LiF:Cu or BeO to SiO2/epoxy mixture of the globe top material, radiation detection limit of chip cards can be reduced as low as a few mGy but the presence of an initial signal in UV cured material as well as gradual increase of the signal are found to be the main limiting factors for detection of low doses

Additives and solvents-induced phase and morphology modification of NaYF_4 for improving up-conversion emission

International Nuclear Information System (INIS)

Zhuang, Jianle; Yang, Xianfeng; Wang, Jing; Lei, Bingfu; Liu, Yingliang; Wu, Mingmei

2016-01-01

Both cubic and hexagonal NaYF_4 were synthesized in different reaction systems via hydro/solvo-thermal route. The effects of reaction temperature, solvents, and additives on the synthesis of NaYF_4 have been studied in detail. It has been shown that phase transformation from cubic NaYF_4 to hexagonal NaYF_4 always occurred. The sequence of the ability for inducing the phase transformation was ethanol>H_2O>acetic acid. It is found that ethanol can not only facilitate the formation of hexagonal NaYF_4 but also control the growth of the crystal. This is quite unusual for the growth of H-NaYF_4. The up-conversion emission properties of Yb/Er co-doped NaYF_4 have also been investigated and the results demonstrated some general principles for improving up-conversion emission. - Graphical abstract: Additives and solvents can induce the phase transformation of NaYF_4, typically the use of organic sodium salt and ethanol. - Highlights: • The effect of additives and solvents on the synthesis of NaYF_4 was studied in detail. • Ethanol can facilitate the formation of H-NaYF_4 while acetic acid restrain it. • Three general principles for improving up-conversion emission were summarized.

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)

Structure and luminescence properties of Dy2O3 doped bismuth-borate glasses

International Nuclear Information System (INIS)

Mugoni, Consuelo; Gatto, C.; Pla-Dalmau, A.; Siligardi, C.

2017-01-01

In this study heavy bismuth-borate glasses were studied as host matrices of Dy 2 O 3 rare earth, for potential application as scintillator materials in high energy physics experiments and in general radiation detection systems. Glass matrices were prepared from 20BaO-xBi 2 O 3 -(80-x)B 2 O 3 (x = 20, 30, 40 mol%) ternary systems and synthesized by the melt-quenching method at different temperatures in order to obtain high density and high transparency in the UV/Vis range. Particularly, the glass manifesting the higher transparency and with sufficiently high density was doped with Dy 2 O 3 (2.5 and 5 mol%) in order to induce the luminescence characteristics. The effects of Bi 2 O 3 and Dy 2 O 3 on density, thermal behaviour, transmission as well as luminescence properties under UV excitation, were investigated. The experimental results show that the synthesized glasses can be considered promising candidate materials as dense scintillators, due to the Dy 3+ centres emission.

Ab initio calculations of cross luminescence materials

International Nuclear Information System (INIS)

Kanchana, V.

2016-01-01

Abintio calculations have been performed to study the structural, electronic, and optical properties of ABX 3 (A=alkali, B=alkaline-earth, and X=halide) compounds. The ground state properties are calculated using the pseudopotential method with the inclusion of van der Waals interaction, which we find inevitable in reproducing the experimental structure properties in alkali iodides because of its layered structure. All calculations were performed using the Full-Potential Linearized Augmented Plane Wave method. The band structures are plotted with various functionals and we find the newly developed Tran and Blaha modified Becke-Johnson potential to improve the band gap significantly. The optical properties such as complex dielectric function, refractive index, and absorption spectra are calculated which clearly reveal the optically isotropic nature of these materials though being structurally anisotropic, which is the key requirement for ceramic scintillators. Cross luminescence materials are very interesting because of its fast decay. One of the major criteria for the cross luminescence to happen is the energy difference between valence band and next deeper core valence band being lesser when compared to energy gap of the compound, so that radiative electronic transition may occur between valence band and core valence band. We found this criteria to be satisfied in all the studied compounds leading to cross luminescence except for KSrI 3 , RbSrI 3 . The present study suggest that among the six compounds studied, CsSrI 3 , CsMgCl 3 , CsCaCl 3 , and CsSrCl 3 compounds are cross luminescence materials, which is well explained from the band structure, optical properties calculations. Chlorides are better scintillators that iodides and CsMgCl 3 is found to be promising one among the studied compounds. Apart from these materials we have also discussed electronic structure and optical properties of other scintillator compounds. (author)

Experimental and first principle study of the structure, electronic, optical and luminescence properties of M-type GdNbO4 phosphor

Science.gov (United States)

Ding, Shoujun; Zhang, Haotian; Zhang, Qingli; Chen, Yuanzhi; Dou, Renqin; Peng, Fang; Liu, Wenpeng; Sun, Dunlu

2018-06-01

In this work, GdNbO4 polycrystalline with monoclinic phase was prepared by traditional high-temperature solid-state reaction. Its structure was determined by X-ray diffraction and its unit cell parameters were obtained with Rietveld refinement method. Its luminescence properties (including absorbance, emission and luminescence lifetime) were investigated with experiment method and the CIE chromaticity coordinate was presented. Furthermore, a systematic theoretical calculation (including band gap, density of states and optical properties) based on the density function theory methods was performed on GdNbO4. Lastly, a comparison between experiment and calculated results was conducted. The calculated and experiment results obtained in this work can provide an essential understanding of GdNbO4 material.

Optical and luminescent properties of the lead and barium molybdates

Energy Technology Data Exchange (ETDEWEB)

Spassky, D.A. E-mail: dima@opts.phys.msu.ru; Ivanov, S.N.; Kolobanov, V.N.; Mikhailin, V.V.; Zemskov, V.N.; Zadneprovski, B.I.; Potkin, L.I

2004-12-01

Time-resolved luminescence as well as excitation and reflectivity spectra of the oriented lead and barium molybdate single crystals were studied using synchrotron radiation. Features in reflectivity spectra in the fundamental absorption region were analyzed. The contribution of electronic states of lead cation to the formation of the bandgap in PbMoO{sub 4} is supposed. The role of lead states in the intrinsic luminescence of PbMoO{sub 4} is discussed.

Chemisorptive luminescence on γ-irradiated magnesium oxide

International Nuclear Information System (INIS)

Breakspere, R.J.; Read, R.L.

1976-01-01

The intensity of a chemisorptive luminescence produced on MgO by oxygen at room temperature is increased by prior γ-irradiation of the MgO, under vacuum, before adsorption. This enhancement of the luminescence increases with radiation dose up to 1.9 x 10 6 rad and is attributed to the interaction between the F + sub (s) centres produced by the radiation and oxygen molecules arriving at the surface from the gas phase. In this work, the spectrum of the emitted luminescence could not be measured. (author)

Luminescent properties of LuPO4-Pr and LuPO4-Eu nanoparticles

International Nuclear Information System (INIS)

Vistovskyy, V.; Malyi, T.; Vas’kiv, A.; Chylii, M.; Mitina, N.; Zaichenko, A.; Gektin, A.; Voloshinovskii, A.

2016-01-01

Spectral-luminescence parameters of LuPO 4 -Eu and LuPO 4 -Pr nanoparticles of different sizes are studied upon excitation by the synchrotron radiation with photon energies 4–40 eV. Influence of the nanoparticle size on Eu 3+ and Pr 3+ impurity luminescence is analyzed for intracenter and recombination excitation. It is shown that the luminescence intensity of impurities in the case of recombination excitation significantly stronger decreases with decreasing of nanoparticle size compared to intracenter excitation. This feature is explained by the influence of thermalization length to nanoparticle size ratio on the recombination luminescence. Electron recombination luminescence inherent for LuPO 4 -Eu nanoparticles shows a weaker dependence on the nanoparticle size than the hole one in LuPO 4 -Pr nanoparticles. The difference between energy states of praseodymium impurity ions in nanoparticles of different sizes is revealed.

Luminescence properties of Eu2+ - activated alkaline-earth silicon-oxynitride MSi2O2-deltaN2+2/3delta (M = Ca, Sr, Ba) : A promising class of novel LED conversion phosphors

NARCIS (Netherlands)

Li, Y.Q.; Delsing, A.C.A.; With, de G.; Hintzen, H.T.J.M.

2005-01-01

The luminescence properties of Eu2+-activated alk.-earth Si-oxynitrides were studied. In the BaO-SiO2-Si3N4 system, a new BaSi2O2N2 compd. was obtained having the monoclinic structure with lattice parameters a 14.070(4), b 7.276(2), c 13.181(3) .ANG., b 107.74(6)°. All MSi2O2-dN2+2/3d:Eu2+ (M = Ca,

Sol-gel synthesis and luminescent properties of red-emitting Y(P,V)O4:Eu(3+) phosphors.

Science.gov (United States)

Zhang, Xinguo; Zhou, Fangxiang; He, Pei; Zhang, Min; Gong, Menglian

2016-02-01

Eu(3+)-activated Y(P,V)O4 phosphors were prepared by the EDTA sol-gel method, and the corresponding morphologies and luminescent properties were investigated. The sample particles were relatively spheroid with size of 2-3 µm and had a smooth surface. The excitation spectra for Y(P,V)O4:Eu(3+) consisted of three strong excitation bands in the 200-350 nm range, which were attributed to a Eu(3+)- O(2-) charge-transfer band and (1)A1-(1) T1/(1) T2 transitions in VO4(3-). The as-synthesized phosphors exhibited a highly efficient red luminescence at 613 nm due to the Eu(3+5) D0-(7) F2 electric dipole transition. With the increase in the V(5+)/P(5+) ratio, the luminescence intensity of the red phosphor under UV excitation was greatly improved due to enhanced VO4(3-) → Eu(3+) energy transfer. Copyright © 2015 John Wiley & Sons, Ltd.

Luminescence property and emission enhancement of YbAlO3:Mn4+ red phosphor by Mg2+ or Li+ ions

Science.gov (United States)

Cao, Renping; Luo, Wenjie; Xu, Haidong; Luo, Zhiyang; Hu, Qianglin; Fu, Ting; Peng, Dedong

2016-03-01

YbAlO3:Mn4+, YbAlO3:Mn4+, Li+, and YbAlO3:Mn4+, Mg2+ phosphors are synthesized by high temperature solid-state reaction method in air. Their crystal structures and luminescence properties are investigated. Photoluminescence excitation (PLE) spectrum monitored at 677 nm contains broad PLE band with three PLE peaks located at ∼318, 395, and 470 nm within the range 220-600 nm. Emission spectra with excitation 318 and 470 nm exhibit three emission band peaks located at ∼645, 677, and 700 nm in the range of 610-800 nm and their corresponding chromaticity coordinates are about (x = 0.6942, y = 0.3057). The possible luminous mechanism of Mn4+ ion is analyzed by the simple energy level diagram of Mn4+ ion. The optimum Mn4+-doped concentration in YbAlO3:Mn4+ phosphor is about 0.4 mol% and the luminescence lifetime of YbAlO3:0.4%Mn4+ phosphor is ∼0.59 ms. Emission intensity of YbAlO3:0.4%Mn4+ phosphor can be enhanced ∼6 times after Mg2+ ion is co-doped and it is ∼2 times when Li+ ion is co-doped. The content in the paper is useful to research new Mn4+-doped luminescence materials and improve luminescence property of other Mn4+-doped phosphors.

Up-conversion emission of Er{sup 3+}/Yb{sup 3+}co-doped BaBi{sub 2}Nb{sub 2}O{sub 9} (BBN) phosphors

Energy Technology Data Exchange (ETDEWEB)

Façanha, M.X., E-mail: marcello.facanha@uece.br [Departamento de Química, Centro de Ciências, Universidade Federal do Ceará (UFC), Fortaleza, Ceará (Brazil); Faculdade de Educação de Crateús (FAEC), Universidade Estadual do Ceará (UECE), Fortaleza, Ceará (Brazil); Laboratório de Telecomunicações e Ciências e Engenharia de Materiais (LOCEM), Universidade Federal do Ceará (UFC), Fortaleza, Ceará (Brazil); Nascimento, J.P.C. do [Departamento de Química, Centro de Ciências, Universidade Federal do Ceará (UFC), Fortaleza, Ceará (Brazil); Laboratório de Telecomunicações e Ciências e Engenharia de Materiais (LOCEM), Universidade Federal do Ceará (UFC), Fortaleza, Ceará (Brazil); Silva, M.A.S., E-mail: marceloassilva@yahoo.com.br [Laboratório de Telecomunicações e Ciências e Engenharia de Materiais (LOCEM), Universidade Federal do Ceará (UFC), Fortaleza, Ceará (Brazil); and others

2017-03-15

On this paper, polycrystalline samples of the tetragonal systems BaBi{sub 2}Nb{sub 2}O{sub 9} (BBN) and BBN co-doped with Er{sup 3+}/Yb{sup 3+} (BBN: 0.04Er{sup 3+}yYb{sup 3+}, where y=0.02, 0.04, 0.06 and 0.08 mol%) were synthesized by the solid state method. The crystalline structure and photoluminescent properties of the ceramic phosphors were investigated by powder X-ray diffraction (PXRD), Raman spectroscopy and spectral analysis of up-conversion (UC) emission. The results reveal that all compositions crystallize in the I4/mmm space group at room temperature, and show UC green emissions (centered at 525 nm and 550 nm) and red (around 660 nm) coming from ({sup 2}H{sub 11/2}, {sup 4}S{sub 3/2}→{sup 4}I{sub 15/2}) and ({sup 4}F{sub 9/2}→{sup 4}I{sub 15/2}) transitions, respectively, under excitation at 980 nm. Increasing variations of the Yb{sup 3+} sensitizer concentration in the host BBN, lead to a significant intensity increase in both UC emissions due to the efficiency of the energy-transfer process. The BBN: 0.04 mol%Er{sup 3+}0.08 mol%Yb{sup 3+} composition showed the higher intensity bands, thus establishing the BBN as an alternative host material for luminescent centers.

Effect of structural packing on the luminescence properties in tungsten bronze compounds M{sub 2}KNb{sub 5}O{sub 15} (M=Ca, Sr, Ba)

Energy Technology Data Exchange (ETDEWEB)

Yin Xin; Shi Liu [State Key Laboratory of High Performance Ceramics and Superfine Microstructures and CAS Key Laboratory of Materials for Energy Conversion, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Wei Ang, E-mail: iamawei@njupt.edu.cn [Key Laboratory for Organic Electronics and Information Displays, 9 Wenyuan Road, Nanjing 210046 (China); Wan Dongyun; Wang Yaoming [State Key Laboratory of High Performance Ceramics and Superfine Microstructures and CAS Key Laboratory of Materials for Energy Conversion, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Huang Fuqiang, E-mail: huangfq@mail.sic.ac.cn [State Key Laboratory of High Performance Ceramics and Superfine Microstructures and CAS Key Laboratory of Materials for Energy Conversion, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China)

2012-08-15

Tungsten bronze compounds M{sub 2}KNb{sub 5}O{sub 15} (M=Ca, Sr, Ba) were successfully synthesized, and the luminescence properties were investigated. Among the three compounds, Ca{sub 2}KNb{sub 5}O{sub 15} showed an obviously broad band of host luminescence at 460 nm with exciting at 269 nm. By doping Eu{sup 3+} into the M sites, Ca{sub 2}KNb{sub 5}O{sub 15}:Eu{sup 3+} displayed strong red emission from Eu{sup 3+} ions characteristic transitions, nearly four times higher than Sr{sub 2}KNb{sub 5}O{sub 15}:Eu{sup 3+} and seven times higher than Ba{sub 2}KNb{sub 5}O{sub 15}:Eu{sup 3+}. Crystal packing factor (PF) was introduced to account for this luminescence difference, lower PF being correlated to higher luminescence intensity for perovskite-related structure. Both the as-prepared compounds and the literature examples were proved to fit this correlation. This can be explained through the influence of the structural packing on the environment distortion and crystal field splitting of the doping site. - Graphical abstract: Tungsten bronze compounds M{sub 2}KNb{sub 5}O{sub 15} (M=Ca, Sr, Ba) show the dependence of luminescence properties on structural packing, among which Ca{sub 2}KNb{sub 5}O{sub 15} has the superior luminescence. Highlights: Black-Right-Pointing-Pointer Tungsten bronze compounds were synthesized by solid state reaction. Black-Right-Pointing-Pointer Ca{sub 2}KNb{sub 5}O{sub 15} displayed remarkably blue host luminescence. Black-Right-Pointing-Pointer Ca{sub 2}KNb{sub 5}O{sub 15}:Eu{sup 3+} showed more intense red emission than M{sub 2}KNb{sub 5}O{sub 15}:Eu{sup 3+} (M=Sr, Ba). Black-Right-Pointing-Pointer The relationship between crystal packing factor and luminescence was obtained.

Luminescence properties of engineered nitrogen vacancy centers in a close surface proximity

Czech Academy of Sciences Publication Activity Database

Petráková, V.; Nesládek, M.; Taylor, Andrew; Fendrych, František; Cígler, Petr; Ledvina, Miroslav; Vacík, Jiří; Štursa, Jan; Kučka, Jan

2011-01-01

Roč. 208, č. 9 (2011), s. 2051-2056 ISSN 1862-6300 R&D Projects : GA AV ČR KAN200100801; GA AV ČR KAN301370701; GA AV ČR(CZ) KAN400480701; GA MŠk(CZ) LD11076 EU Projects : European Commission(XE) 245122 - DINAMO Grant - others:GA MŠk(CZ) LD11078; European RD projects (XE) 238201-MATCON Institutional research plan: CEZ:AV0Z40550506; CEZ:AV0Z10100520; CEZ:AV0Z10480505 Keywords : diamond * luminescence properties * nitrogen-vacancy * surface proximity Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.463, year: 2011

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.

Luminescence properties of undoped CsCaCl3 and CsSrCl3 crystalline scintillators

International Nuclear Information System (INIS)

Fujimoto, Yutaka; Saeki, Keiichiro; Koshimizu, Masanori; Asai, Keisuke; Yanagida, Takayuki

2015-01-01

Intrinsic luminescence properties of undoped CsCaCl 3 and CsSrCl 3 crystalline scintillators were studied. The crystal samples were grown by a vertical Bridgman method. Photoluminescence spectra of the crystals showed Auger-free luminescence (AFL) at 310 nm and self-trapped emission (STE) at 400 nm for CsCaCl 3 and 465 nm for CsSrCl 3 , when vacuum ultraviolet (VUV) light at 84 nm and 160 nm excited the crystals. X-ray excited radioluminescence spectra of the crystals showed some emission bands in the 280-600 nm wavelength range, which are owing to AFL, STE, and other origins such as lattice defects and impurities. Scintillation light yield was 400-300 ph/MeV, and the principal scintillation decay time about 2.5 ns and 12 ns for CsCaCl 3 and 1.8 ns and 13 ns for CsSrCl 3 . (author)

Luminescence evolution of porous GaN thin films prepared via UV-assisted electrochemical etching

International Nuclear Information System (INIS)

Cheah, S.F.; Lee, S.C.; Ng, S.S.; Yam, F.K.; Abu Hassan, H.; Hassan, Z.

2015-01-01

Porous gallium nitride (GaN) thin films with different surface morphologies and free carriers properties were fabricated from Si-doped GaN thin films using ultra-violet assisted electrochemical etching approach under various etching voltages. Fluctuation of luminescence signals was observed in the photoluminescence spectra of porous GaN thin films. Taking advantage of the spectral sensitivity of infrared attenuated total reflection spectroscopy on semiconductor materials, roles of free carriers and porous structure in controlling luminescence properties of GaN were investigated thoroughly. The results revealed that enhancement in luminescence signal is not always attained upon porosification. Although porosification is correlated to the luminescence enhancement, however, free carrier is the primary factor to enhance luminescence intensity. Due to unavoidable significant reduction of free carriers from Si-doped GaN in the porosification process, control of etching depth (i.e., thickness of porous layer formed from the Si-doped layer) is critical in fabricating porous GaN thin film with enhanced luminescence response. - Highlights: • Various pore morphologies with free carrier properties are produced by Si-doped GaN. • Free carriers are important to control the luminescence signal of porous GaN. • Enhancement of luminescence signal relies on the pore depth of Si-doped layer

Optical and luminescence properties of Dy3+ doped sodium silicate glass

Science.gov (United States)

Srisittipokakun, N.; Kaewkhao, J.

2017-07-01

The aim of the present work is to study the optical and luminescence properties of Dy2O3 doped Na2O-BaO-Bi2O3-SiO2 glasses. The Dy3+ ion is chosen as dopant because it emits three visible bands, blue (470-485 nm; 4F9/2→6H15/2), yellow (570-580 nm; 4F9/2→6H13/2) and red (640-655 nm; 4F9/2→6H11/2) luminescence and finds its applications in the fields of laser, white LEDs, telecommunication technology and display devices. NaBaBiSiDy glasses with the compositions of (30-x)SiO2: 10Bi2O3: 30Na2O: 30BaO: xDy2O3 where x=0.0, 0.1, 0.5, 1.0, 1.5 and 2.0 mol% were prepared by melt-quenching technique and characterized by using density, optical absorption photoluminescence (PL) and decay rate measurements as function of different concentrations. The density (ρ), molar volume (VM) and refractive index obtained were found to increase with increase in the concentration of Dy2O3 in the glass matrix. The chromaticity coordinates were calculated from emission spectra and analyzed with CIE color diagram and appear in the white light region under ultraviolet excitation.

Maximizing and stabilizing luminescence from halide perovskites with potassium passivation

Science.gov (United States)

Abdi-Jalebi, Mojtaba; Andaji-Garmaroudi, Zahra; Cacovich, Stefania; Stavrakas, Camille; Philippe, Bertrand; Richter, Johannes M.; Alsari, Mejd; Booker, Edward P.; Hutter, Eline M.; Pearson, Andrew J.; Lilliu, Samuele; Savenije, Tom J.; Rensmo, Håkan; Divitini, Giorgio; Ducati, Caterina; Friend, Richard H.; Stranks, Samuel D.

2018-03-01

Metal halide perovskites are of great interest for various high-performance optoelectronic applications. The ability to tune the perovskite bandgap continuously by modifying the chemical composition opens up applications for perovskites as coloured emitters, in building-integrated photovoltaics, and as components of tandem photovoltaics to increase the power conversion efficiency. Nevertheless, performance is limited by non-radiative losses, with luminescence yields in state-of-the-art perovskite solar cells still far from 100 per cent under standard solar illumination conditions. Furthermore, in mixed halide perovskite systems designed for continuous bandgap tunability (bandgaps of approximately 1.7 to 1.9 electronvolts), photoinduced ion segregation leads to bandgap instabilities. Here we demonstrate substantial mitigation of both non-radiative losses and photoinduced ion migration in perovskite films and interfaces by decorating the surfaces and grain boundaries with passivating potassium halide layers. We demonstrate external photoluminescence quantum yields of 66 per cent, which translate to internal yields that exceed 95 per cent. The high luminescence yields are achieved while maintaining high mobilities of more than 40 square centimetres per volt per second, providing the elusive combination of both high luminescence and excellent charge transport. When interfaced with electrodes in a solar cell device stack, the external luminescence yield—a quantity that must be maximized to obtain high efficiency—remains as high as 15 per cent, indicating very clean interfaces. We also demonstrate the inhibition of transient photoinduced ion-migration processes across a wide range of mixed halide perovskite bandgaps in materials that exhibit bandgap instabilities when unpassivated. We validate these results in fully operating solar cells. Our work represents an important advance in the construction of tunable metal halide perovskite films and interfaces that can

Structural, morphological and luminescence properties of nanocrystalline up-converting Y{sub 1.89}Yb{sub 0.1}Er{sub 0.01}O{sub 3} phosphor particles synthesized through aerosol route

Energy Technology Data Exchange (ETDEWEB)

Lojpur, V.; Mancic, L. [Institute of Technical Sciences of the Serbian Academy of Sciences and Arts, K. Mihailova 35/IV, 11000 Belgrade (Serbia); Rabanal, M.E. [University Carlos III of Madrid, Avd. Universidad 30, 28911 Leganes, Madrid (Spain); Dramicanin, M.D. [Vinca Institute of Nuclear Science, University of Belgrade, P.O. Box 522, Belgrade (Serbia); Tan, Z.; Hashishin, T.; Ohara, S. [JWRI, Osaka University, 11-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Milosevic, O., E-mail: olivera.milosevic@itn.sanu.ac.rs [Institute of Technical Sciences of the Serbian Academy of Sciences and Arts, K. Mihailova 35/IV, 11000 Belgrade (Serbia)

2013-12-15

Highlights: •The Y{sub 1.89}Yb{sub 0.1}Er{sub 0.01}O{sub 3} phosphor particles are synthesized via aerosol route. •We report influence of process parameters on the particle structure and morphology. •Spherical, submicronic size and nano-crystalline particle morphology are confirmed. •The particles show improved luminescence properties and decay time. •Synthesized powders exhibit the temperature dependant up-conversion emission. -- Abstract: Nanocrystalline up-converting Y{sub 2}O{sub 3}:Yb{sup 3+}, Er{sup 3+} phosphor particles were processed in a dispersed system-aerosol, generated ultrasonically at 1.3 MHz from common nitrate precursor solution having fixed ytterbium-to-erbium concentration ratio. The appropriate process parameters: residence time 21 s, carrier gas (air) flow rate 1.6 dm{sup 3}/min, synthesis temperature 900 °C, led to the formation of un-agglomerated spherical nanostructured secondary particles, having mean particle size of approx 450 nm, composed of primary nanoscaled (20 nm) subunits. In order to reach targeting phase crystallinity, the as-prepared particles were additionally annealed at 1100 °C in air for 12, 24 and 48 h, respectively. Particle structure, morphology and purity were analyzed by X-ray powder diffraction (XRPD), scanning electron microscopy (FESEM/SEM), analytical and high resolution transmission electron microscopy (TEM/HRTEM) in combination with energy dispersive X-ray analysis and Fourier Transform Infrared Spectroscopy (FTIR). All samples crystallized in a cubic bixbyte-structure, space group Ia-3. The crystallite size changed with annealing time from 30 nm in as-prepared sample to 135 nm in sample annealed for 48 h, respectively. Emission spectra were assigned to the following trivalent erbium f–f electronic transitions: {sup 2}H{sub 9/2} → {sup 4}I{sub 15/2} (blue: 407–420 nm), ({sup 2}H{sub 11/2}, {sup 4}S{sub 3/2}) → {sup 4}I{sub 15/2} (green: 510–590 nm), and {sup 4}F{sub 9/2} → {sup 4}I{sub 15

Contribution to numerical radiology. Study of a bidimensional imaging device that use Electrically Stimulated Luminescence. The case of mammography

International Nuclear Information System (INIS)

Ayral, Jean-Luc

1990-01-01

Projection radiography is in a fast change period. This work describes the study and demonstration of a new type of 2D flat X-Ray sensor for mammography and delivering a digital signal. X-ray transmission study of breast tissues leads to: a- definition of X-Ray photons properties for optimized signal-to-noise ratio, and b-specifications of a 2D X-Ray sensor such as mean exposure, dynamic range and pixel size. Then the X-Ray detection processes using a direct or a delayed luminescence mechanism are reviewed. The detailed analysis of the different ways for detecting visible photons is combined with the System specifications (pixel size, image reading time) in order to characterize (from a signal-to-noise ratio aspect) an X-Ray imaging system integrating a delayed luminescence property. The imaging plate and associated luminescent material are specified by their minimum X-Ray absorption and conversion gain. The Gudden- Pohl effect, or Electrically Stimulated Luminescence (ESL) is experimentally studied and quantified under X-Ray excitation in ZnCdS: Cu, Al materials. An original UV sensitization technique opens us the way to highly reproducible results and large sensitivity. The obtained information storage time in the material is compatible with a delayed image reading. These results allow the achievement of an X-Ray imaging demonstrator integrating the ESL imaging plate, an intensified CCD sensor and the sensitization technique. First images are obtained. Further conception of real dimension X-Ray imaging System for mammography is described. (author) [fr

Solubility limit and luminescence properties of Eu{sup 3+} ions in Al{sub 2}O{sub 3} powder

Energy Technology Data Exchange (ETDEWEB)

Onishi, Yuya; Nakamura, Toshihiro, E-mail: tnakamura@gunma-u.ac.jp; Adachi, Sadao, E-mail: adachi@gunma-u.ac.jp

2016-08-15

Al–Eu–O compounds are synthesized from Al{sub 2}O{sub 3}:Eu{sub 2}O{sub 3}=(1–x):x mixtures (x=0–0.15) by the metal organic decomposition method and subsequently calcined at various temperatures from T{sub c}=750 to 1200 °C in dry O{sub 2} atmosphere. The structural and luminescence properties of these compounds are investigated using X-ray diffraction analysis, photoluminescence (PL) analysis, PL excitation spectroscopy, and luminescence lifetime measurements. The present study focuses on the effects of the Eu{sub 2}O{sub 3} addition (x) on the material and phosphor properties of Al{sub 2}O{sub 3}:Eu{sup 3+}. The stable phase of α-Al{sub 2}O{sub 3} is synthesized at T{sub c}>1100 °C and cubic γ-Al{sub 2}O{sub 3} phase at T{sub c}≤1100 °C. The calcination temperature dependence of the PL intensity yields an activation of E{sub a}~0.8 eV for Eu{sup 3+} ions in the Al{sub 2}O{sub 3} host. The luminescence decay time is determined to be ~0.8 ms, independent of x. Temperature dependence of the PL intensity at T=20–450 K exhibits thermal quenching behavior with energies of 17 meV and 0.28 eV at low (<200 K) and high temperatures (>200 K), respectively. The solubility limit of Eu{sup 3+} ions in α-Al{sub 2}O{sub 3} is determined to be ~1%. The schematic energy-level diagram of Eu{sup 3+} in α-Al{sub 2}O{sub 3} is also proposed for the sake of a better understanding of the luminescence process of this phosphor system.

Synthesis and luminescence properties of novel LiSrPO{sub 4}:Dy{sup 3+} phosphor

Energy Technology Data Exchange (ETDEWEB)

Sun, Jiayue, E-mail: jiayue_sun@126.com [School of Science, Beijing Technology and Business University, Beijing 100048 (China); Zhang, Xiangyan [School of Science, Beijing Technology and Business University, Beijing 100048 (China); Xia, Zhiguo, E-mail: xiazg426@yahoo.com.cn [School of Materials Sciences and Technology, China University of Geosciences, Beijing 100083 (China); Du, Haiyan [School of Science, Beijing Technology and Business University, Beijing 100048 (China)

2011-11-15

Graphical abstract: Novel LiSrPO4:Dy{sup 3+} phosphors were synthesized by solid-state reaction, and Dy{sup 3+}-doped concentration dependent luminescence properties, concentration quenching effect and the decay times were investigated in detail. Highlights: {yields} LiSrPO{sub 4}:Dy{sup 3+} could be excited by UV light and exhibited blue and yellow emission. {yields} Concentration quenching effect of LiSrPO{sub 4}:Dy{sup 3+} samples were investigated in detail. {yields} Decay times are estimated to be 0.57-0.89 ms for Dy{sup 3+} in LiSrPO{sub 4} host. -- Abstract: Novel LiSrPO{sub 4}:Dy{sup 3+} phosphors for white light-emitting diodes (w-LEDs) were synthesized by the conventional solid-state reaction. X-ray powder diffraction (XRD) analysis confirmed the phase formation of LiSrPO{sub 4}:Dy{sup 3+} materials. Luminescence properties results showed that the phosphor could be efficiently excited by the UV-vis light region from 250 to 460 nm, and it exhibited blue (483 nm) and yellow (574 nm) emission corresponding to {sup 4}F{sub 9/2} {yields} {sup 6}H{sub 15/2} transitions and {sup 4}F{sub 9/2} {yields} {sup 6}H{sub 13}/{sub 2} transitions, respectively. The luminescence intensity of LiSrPO{sub 4}:xDy{sup 3+} phosphor firstly increased and then decreased with increasing Dy{sup 3+} concentration, and reached the maximum at x = 0.03. It was found that concentration quenching occurred as a result of dipole-dipole interaction according to the Dexter's theory. The decay time was also determined for various concentrations of Dy{sup 3+} in LiSrPO{sub 4}.

Enhanced luminescence from silver nanoparticles integrated Er{sup 3+}-doped boro-tellurite glasses: Impact of annealing temperature

Energy Technology Data Exchange (ETDEWEB)

Said Mahraz, Zahra Ashur; Sahar, M.R., E-mail: mrahim057@gmail.com; Ghoshal, S.K.

2015-11-15

Considerable enhancement of rare earth ions luminescence intensity stimulated via metal nanoparticles (NPs) inclusion inside inorganic glass matrix opened a new avenue to achieving efficient lasing glass media. Tuning the localised surface plasmon resonance (LSPR) band of noble metal NPs through their precise size manipulation is demonstrated to be the key for such accomplishment. We report the influences of annealing (heat treatment) temperature (AT) on the down-conversion luminescence features of erbium (Er{sup 3+}) doped zinc-boro-tellurite (ZBT) glasses containing silver NPs. The AT dependent (between 390 and 450 °C) variations in refractive index and density are ascribed to the generation of non-bridging oxygen (NBO) ions. X-ray diffraction pattern confirmed the amorphous nature of the melt-quenched synthesized glass samples. TEM micrograph revealed the nucleation of Ag NPs inside the glass matrix having average diameter between 8.4 (un-annealed sample) to 11.8 nm (annealed). The UV–Vis spectra exhibited seven absorption bands corresponding to {sup 4}f–{sup 4}f transitions of Er{sup 3+} ions. Annealed samples displayed a red shift of SPR bands positioned at 550 and 580 nm. Judd–Ofelt theory is used to evaluate the intensity parameters for radiative transitions within 4f{sup n} configuration of Er{sup 3+} ion. Annealing up to 410 °C is found to stimulate the plasmonic effect through the enlargement of NPs. Consequently, the PL intensity is enhanced by a factor of 3.23 ({sup 2}H{sub 11/2} → {sup 4}I{sub 15/2}), 4.10 ({sup 4}S{sub 3/2} → {sup 4}I{sub 15/2}), and 3.79 ({sup 4}F{sub 9/2} → {sup 4}I{sub 15/2}). This achieved excellent down-conversion luminescence efficiency of proposed glasses shows their potential implementation in photonic devices and solid state lasers. - Highlights: • The changes in the physical properties are ascribed to the generation of NBO. • TEM images confirmed the presence of Ag NPs in the glass matrix. • The achieved

Luminescence spectroscopy with synchrotron radiation: History, highlights, future

International Nuclear Information System (INIS)

Zimmerer, Georg

2006-01-01

Luminescence spectroscopy and the investigation of dynamical processes with synchrotron radiation (SR) started about 35 years ago in nearly all SR laboratories existing at that time. In the present paper, the pioneering experiments are particularly emphasized. The exciting development is illustrated presenting highlights for the whole period from the beginning to the present day. The highlights are taken from fields like exciton self-trapping, inelastic electron-electron scattering, optically stimulated desorption, cross luminescence, or probing of cluster properties with luminescence spectroscopic methods. More technological aspects play a role in present day's experiments, like quantum cutting in rare-earth-doped insulators. Promising two-photon excitation and light amplification experiments with SR will be included, as well as the first results obtained in a luminescence experiment with selective Vaccum ultraviolet-free electron laser excitation. Finally, a few ideas concerning the future development of luminescence spectroscopy with SR will be sketched

Effect of ultrasound treatment on the morpho-structural and luminescent characteristics of cerium doped yttrium silicate phosphors

Energy Technology Data Exchange (ETDEWEB)

Muresan, L.E., E-mail: laura_muresan2003@yahoo.com [“Raluca Ripan” Institute for Research in Chemistry, Babeş Bolyai University, Fântânele 30, 400294 Cluj-Napoca (Romania); Cadis, A.I.; Perhaita, I. [“Raluca Ripan” Institute for Research in Chemistry, Babeş Bolyai University, Fântânele 30, 400294 Cluj-Napoca (Romania); Silipas, D.T. [National Institute for R& D of Isotopic and Molecular Technologies, Donath 67-103, 400293 Cluj-Napoca (Romania); Tudoran, L. Barbu [Electronic Microscopy Centre, Babeş Bolyai University, Clinicilor 37, 400006 Cluj-Napoca (Romania)

2015-08-15

Highlights: • Y{sub 2}SiO{sub 5}:Ce is prepared by gel combustion in ultrasound conditions (US). • Morpho-structural characteristics are revealed based on FTIR, SEM, XRD, BET. • Incorporation of Ce{sup 3+} in X1/X2 type centers depends on preparative conditions. • US treatment increases the luminescent performances up to 151%. - Abstract: Cerium activated yttrium silicate (Y{sub 2}SiO{sub 5}:Ce) phosphors were prepared by gel-combustion, using yttrium–cerium nitrate as oxidizer, aspartic acid as fuel and TEOS as source of silicon. Two modalities for samples preparation were approached namely: the classical gel-combustion and sonication gel-combustion. The ultrasound treatment during the gelling stage has a positive effect on the structural and luminescent characteristics of the final product. Therefore, a well crystallized single X2–Y{sub 2}SiO{sub 5} phase phosphor was obtained at 1200 °C. Based on FT-IR and XRD investigations, conversion of X1 to X2–Y{sub 2}SiO{sub 5} phases is observed as the firing temperature is varied (1100 °C, 1200 °C, 1300 °C 1400 °C). The ultrasound treatment leads to smaller particle size and enhances the luminescent performances up to 151% in comparison with samples prepared by classical way.

Electrical, luminescent, and deep trap properties of Si doped n-GaN grown by pendeo epitaxy

Energy Technology Data Exchange (ETDEWEB)

Polyakov, A. Y. [National University of Science and Technology MISiS, Leninskiy pr. 4, Moscow 119049 (Russian Federation); Smirnov, N. B. [National University of Science and Technology MISiS, Leninskiy pr. 4, Moscow 119049 (Russian Federation); Institute of Rare Metals, B. Tolmachevsky, 5, Moscow 119017 (Russian Federation); Yakimov, E. B. [National University of Science and Technology MISiS, Leninskiy pr. 4, Moscow 119049 (Russian Federation); Institute of Microelectronics Technology and High Purity Materials, Russian Academy of Science, 6, Academician Ossipyan str., Chernogolovka, Moscow Region 142432 (Russian Federation); Lee, In-Hwan, E-mail: ihlee@jbnu.ac.kr [School of Advanced Materials Engineering and Research Center of Advanced Materials Development, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Pearton, S. J. [University of Florida, Gainesville, Florida 32611 (United States)

2016-01-07

Electrical and luminescent properties and deep trap spectra of Si doped GaN films grown by maskless epitaxial lateral overgrowth (MELO) are reported. The dislocation density in the wing region of the structure was 10{sup 6 }cm{sup −2}, while in the seed region it was 10{sup 8 }cm{sup −2}. The major electron traps present had activation energy of 0.56 eV and concentrations in the high 10{sup 15 }cm{sup −3} range. A comparison of diffusion length values and 0.56 eV trap concentration in MELO GaN and epitaxial lateral overgrowth (ELOG) GaN showed a good correlation, suggesting these traps could be effective in carrier recombination. The doped MELO films were more uniform in their electrical properties than either ELOG films or undoped MELO films. We also discuss the differences in deep trap spectra and luminescence spectra of low-dislocation-density MELO, ELOG, and bulk n-GaN samples grown by hydride vapor phase epitaxy. It is suggested that the observed differences could be caused by the differences in oxygen and carbon contamination levels.

Study on the light-color mixing of rare earth luminescent materials for anti-counterfeiting application

Science.gov (United States)

Zhang, Jishu; Zhang, Yingzi; Tao, Jin; Zhu, Yanan

2018-04-01

In order to find out the light color mixing mechanism of rare earth luminescent materials used in anti-counterfeiting fibers, we prepared three kinds of rare earth luminescent materials according to RGB tri-primary color, and mixed it together to form different mixtures in certain proportion. The phase structures of the luminescent material monomers were measured by x-ray diffractometer. The photochromic properties of the luminescent materials were tested and analyzed by fluorescence spectrophotometer. The results show that the light color mixing was consistent with the blending principle of additive color, but not the same because of the photochromic properties of rare earth luminescent materials, and we explored the reasons in the light wavelength and intensity. It was found that the enhancement of the luminescence intensity of the mixture on account of the superimposing of luminescence.

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

Phase transformation, morphology evolution and luminescence property variation in Y2O3: Eu hollow microspheres

International Nuclear Information System (INIS)

Wang, Qin; Guo, Jing; Jia, Wenjing; Liu, Baocang; Zhang, Jun

2012-01-01

Highlights: ► We report a general and facile method for the synthesis of Y 2 O 3 : Eu hollow microspheres. ► This method may be of great significance in the synthesis of many other hollow spherical materials. ► Phase, morphology and luminescence property were found to be strongly dependent on temperature and pH. ► The evolution process under various temperatures and pH values were discussed. ► The sample shows a strong red emission under short UV irradiation, and the lifetime is determined to be 7.0 ms. - Abstract: Y 2 O 3 : Eu hollow microspheres with average size of 500–600 nm have been successfully synthesized via a solvothermal method in the presence of sodium citrate as surfactant followed by a subsequent heat treatment process. High polymer F127(EO 106 PO 70 EO 106 ) served as a soft template in the formation of as prepared hollow microspheres. It is found that the pH values and the reaction temperature are two crucial factors in determining the phase, morphology and luminescence properties of the Y 2 O 3 : Eu hollow microspheres. Morphology evolution can be achieved by changing the pH and the reaction temperature. The properties of the Eu 3+ -doped Y 2 O 3 : Eu nanocrystals were characterized by XRD, FE-SEM, HR-TEM and UV–vis spectroscopy.

Synthesis of in-situ luminescent ZnS nanoparticles facile with CTAB micelles and their properties study

Energy Technology Data Exchange (ETDEWEB)

Shukla, Vaishali [Centre for Nanoscience, Central University of Gujarat, Gandhinagar (India); Singh, Man [School of Chemical Sciences, Central University of Gujarat, Gandhinagar, India Telephone: 079-23260210, fax: 079-23260076 (India)

2016-04-13

Currently, the development of micelles route is thrust area of research in nanoscience for the control particle size and remarkable properties through chemical co-precipitation method. A 0.9 mM aqueous CTAB micellar solution plays a role as capping agent in the homogeneous solution of 0.5 M ZnSO{sub 4} and 0.5 M Na{sub 2}S for synthesis, further precipitates purified with centrifugation in cold ethanol and millipore water to remove unreacted reagents and ionic salt particles. A resultant, white colored luminescent ZnS nanoparticle out with ∼95% yield is reported. The ZnS nanoparticles have been examined by their luminescence properties, optical properties and crystal structure. The mean particle size of ZnS nanoparticles is found to be ∼10 nm in various technical results and UV-absorption was 80 nm blue shifts moved from 345 nm (bulk material) to 265 nm, showing a quantum size impact. The X-ray diffraction (XRD) pattern shows the immaculate cubic phase. Photoluminescence (PL) investigates the recombination mechanism with blue emission from shallow electron traps at 490 nm in ZnS nanoparticles. An FTIR spectrum and Thermal gravimetric analysis (TGA) gives confirmation of CTAB – cationic surfactant on surface of ZnS nanoparticle as capping agent as well thermal stability of CTAB capped ZnS nanoparticles with respect to temperature.

Improvement of conversion efficiency of silicon solar cells using up-conversion molybdate La2Mo2O9:Yb,R (R=Er, Ho) phosphors

Institute of Scientific and Technical Information of China (English)

Yen-Chi Chen; Teng-Ming Chen

2011-01-01

The goal of this work was aimed to improve the power conversion efficiency of single crystalline silicon-based photovoltaic cells by using the solar spectral conversion principle,which employs an up-conversion phosphor to convert a low energy infrared photon to the more energetic visible photons to improve the spectral response.In this study,the surface of multicrystalline silicon solar cells was coated with an up-conversion molybdate phosphor to improve the spectral response of the solar cell in the ncar-infiared spectral range.The short circuit current (Isc),open circuit voltage (Voc),and conversion efficiency (η) of spectral conversion cells were measured.Preliminary experimental results revealed that the light conversion efficiency of a 1.5％-2.7％ increase in Si-based cell was achieved.

Anodic luminescence, structural, photoluminescent, and photocatalytic properties of anodic oxide films grown on niobium in phosphoric acid

Energy Technology Data Exchange (ETDEWEB)

Stojadinović, Stevan, E-mail: sstevan@ff.bg.ac.rs [University of Belgrade, Faculty of Physics, Studentski trg 12-16, 11000 Belgrade (Serbia); Tadić, Nenad [University of Belgrade, Faculty of Physics, Studentski trg 12-16, 11000 Belgrade (Serbia); Radić, Nenad [University of Belgrade, Institute of Chemistry, Technology and Metallurgy, Department of Catalysis and Chemical Engineering, Njegoševa 12, 11000 Belgrade (Serbia); Stefanov, Plamen [Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Block 11, 1113 Sofia (Bulgaria); Grbić, Boško [University of Belgrade, Institute of Chemistry, Technology and Metallurgy, Department of Catalysis and Chemical Engineering, Njegoševa 12, 11000 Belgrade (Serbia); Vasilić, Rastko [University of Belgrade, Faculty of Physics, Studentski trg 12-16, 11000 Belgrade (Serbia)

2015-11-15

Graphical abstract: - Highlights: • Anodic luminescence is correlated to the existence of morphological defects in the oxide. • Spectrum under spark discharging reveals only oxygen and hydrogen lines. • Oxide films formed under spark discharging are crystallized and composed of Nb{sub 2}O{sub 5}. • Photocatalytic activity and photoluminescence of Nb{sub 2}O{sub 5} films increase with time. - Abstract: This article reports on properties of oxide films obtained by anodization of niobium in phosphoric acid before and after the dielectric breakdown. Weak anodic luminescence of barrier oxide films formed during the anodization of niobium is correlated to the existence of morphological defects in the oxide layer. Small sized sparks generated by dielectric breakdown of formed oxide film cause rapid increase of luminescence intensity. The luminescence spectrum of obtained films on niobium under spark discharging is composed of continuum radiation and spectral lines caused by electronic spark discharging transitions in oxygen and hydrogen atoms. Oxide films formed before the breakdown are amorphous, while after the breakdown oxide films are partly crystalline and mainly composed of Nb{sub 2}O{sub 5} hexagonal phase. The photocatalytic activity of obtained oxide films after the breakdown was investigated by monitoring the degradation of methyl orange. Increase of the photocatalytic activity with time is related to an increase of oxygen vacancy defects in oxide films formed during the process. Also, higher concentration of oxygen vacancy defects in oxide films results in higher photoluminescence intensity.

Luminescence properties of Sm"3"+ doped YPO_4: Effect of solvent, heat-treatment, Ca"2"+/W"6"+-co-doping and its hyperthermia application

International Nuclear Information System (INIS)

Dutta, Dimple P.; Ningthoujam, R. S.; Tyagi, A. K.

2012-01-01

Sm"3"+ doped YPO_4 spherical nanoparticles are prepared by wet chemical route. Pure YPO_4 shows the tetragonal phase, which is stable up to 900 °C, whereas pure SmPO_4 shows the phase transition from hexagonal to monoclinic when heated above 800 °C. The (2-10 at.%) Sm"3"+ doped YPO_4 shows the mixture of phases of tetragonal and hexagonal, which transform to the tetragonal phase above 800 °C. Infra-red study could distinguish confined water in the pore of hexagonal phase from water present on the surface of particles. Luminescence intensities of Sm"3"+ at 564, 601 and 645 nm are weak in case of as-prepared samples because of high non-radiative rate arising from the H_2O molecules present in pores of hexagonal lattice. The intensities increase for samples heated up to 900 °C because of increase of extent of radiative rate. Luminescence lifetime increases with increase of heat-treatment up to 900 °C. When solvent of as-prepared sample was changed from the H_2O to D_2O, 5 times enhancement in luminescence intensity is observed, which can be ascribed to the lower vibration energy of D-O over H-O, which is near to Sm"3"+. When Y"3"+ and P"5"+ ions are substituted by Ca"3"+ and W"3"+ up to 3 at.%, there is an enhancement of luminescence. In order to use them as bio-labeling in drug delivery for hyperthermia applications, hybrid of Fe_3O_4@YPO_4:7Sm is prepared and heating up to 45 °C is observed under AC magnetic field.

Oxygen influence on luminescence properties of rare-earth doped NaLaF{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Tuomela, A., E-mail: anu.tuomela@oulu.fi [Research Center of Molecular Materials, University of Oulu, P.O. Box 3000, FIN-90014 (Finland); Pankratov, V., E-mail: vladimirs.pankratovs@oulu.fi [Research Center of Molecular Materials, University of Oulu, P.O. Box 3000, FIN-90014 (Finland); Sarakovskis, A.; Doke, G.; Grinberga, L. [Institute of Solid State Physics, University of Latvia, 8 Kengaraga, LV-1063 Riga (Latvia); Vielhauer, S. [Institute of Physics, University of Tartu, Riia 142, Tartu 51014 (Estonia); Huttula, M. [Research Center of Molecular Materials, University of Oulu, P.O. Box 3000, FIN-90014 (Finland)

2016-11-15

Luminescence properties of erbium and europium doped NaLaF{sub 4} with different oxygen content have been studied. Vacuum ultraviolet (VUV) excitation luminescence spectroscopy technique has been applied by using synchrotron radiation excitation. It was found that oxygen impurity leads to significant degradation of Er{sup 3+} or Eu{sup 3+} emission under VUV excitation. The intensive O{sup 2−}–Er{sup 3+} charge transfer excitation band has been detected from oxygen abundant NaLaF{sub 4} in the 150–165 nm spectral range. This band reveals a competing absorption mechanism in oxygen containing NaLaF{sub 4}. It is clearly demonstrated that one reason for the Er{sup 3+} emission degradation in oxygen abundant NaLaF{sub 4} is strong suppression of 4f–5d transitions in Er{sup 3+} ion. The degradation of the Eu{sup 3+} emission under VUV excitation was explained by diminishing of F{sup −}–Eu{sup 3+} charge transfer absorption band as well as by competing relaxation centers in the oxygen abundant NaLaF{sub 4}.

Luminescence and Luminescence Quenching of K2Bi(PO4)(MoO4):Eu3+ Phosphors with Efficiencies Close to Unity.

Science.gov (United States)

Grigorjevaite, Julija; Katelnikovas, Arturas

2016-11-23

A very good light emitting diode (LED) phosphor must have strong absorption, high quantum efficiency, high color purity, and high quenching temperature. Our synthesized K 2 Bi(PO 4 )(MoO 4 ):Eu 3+ phosphors possess all of the mentioned properties. The excitation of these phosphors with the near-UV or blue radiation results in a bright red luminescence dominated by the 5 D 0 → 7 F 2 transition at ∼615 nm. Color coordinates are very stable when changing Eu 3+ concentration or temperature in the range of 77-500 K. Furthermore, samples doped with 50% and 75% Eu 3+ showed quantum efficiencies close to 100% which is a huge benefit for practical application. Temperature dependent luminescence measurements showed that phosphor performance increases with increasing Eu 3+ concentration. K 2 Eu(PO 4 )(MoO 4 ) sample at 400 K lost only 20% of the initial intensity at 77 K and would lose half of the intensity only at 578 K. Besides, the ceramic disks with thicknesses of 0.33 and 0.89 mm were prepared from K 2 Eu(PO 4 )(MoO 4 ) powder, and it turned out that they efficiently converted the radiation of 375 nm LED to the red light. The conversion of 400 nm LED radiation to the red light was not complete; thus, the light sources with various tints of purple color were obtained. The combination of ceramic disks with 455 nm LED yielded the light sources with tints of blue color due to the low absorption of ceramic disk in this spectral range. In addition, these phosphors possess a very unique emission spectra; thus, they could also be applied in luminescent security pigments.

Silica-modified luminescent LaPO4 :Eu@LaPO4 @SiO2 core/shell nanorods: Synthesis, structural and luminescent properties.

Science.gov (United States)

Ansari, Anees A

2018-02-01

Monoclinic-type tetragonal LaPO 4 :Eu (core) and LaPO 4 :Eu@LaPO 4 (core/shell) nanorods (NRs) were successfully prepared using a urea-based co-precipitation process under ambient conditions. An amorphous silica layer was coated around the luminescent core/shell NRs via the sol-gel process to improve their solubility and colloidal stability in aqueous and non-aqueous media. The prepared nano-products were systematically characterized by X-ray diffraction pattern, transmission electron microscopy, energy dispersive X-ray analysis, and FTIR, UV/Vis, and photoluminescence spectroscopy to examine their phase purity, crystal phase, surface chemistry, solubility and luminescence characteristics. The length and diameter of the nano-products were in the range 80-120 nm and 10-15 nm, respectively. High solubility of the silica-modified core/shell/Si NRs was found for the aqueous medium. The luminescent core NRs exhibited characteristic excitation and emission transitions in the visible region that were greatly affected by surface growth of insulating LaPO 4 and silica layers due to the multiphonon relaxation rate. Our luminescence spectral results clearly show a distinct difference in intensities for core, core/shell, and core/shell/Si NRs. Highly luminescent NRs with good solubility could be useful candidates for a variety of photonic-based biomedical applications. Copyright © 2017 John Wiley & Sons, Ltd.

Contribution to digital radiography. Study of a 2D X-ray sensor for mammography using the electrically-stimulated-luminescence effect

International Nuclear Information System (INIS)

Ayral, Jean-Luc

1990-01-01

Radiography is in a fast change period. This work describes the study and demonstration of a new type of 2D flat X-Ray sensor for mammography and delivering a digital signal. X-ray transmission study of breast tissues leads to: a-definition of X-Ray photons properties for optimized signal-to-noise ratio, and b-specifications of a 2D X-Ray sensor such as mean exposure, dynamic range and pixel size. Then the X-Ray detection processes using a direct or a delayed luminescence mechanism are reviewed. The detailed analysis of the different ways for detecting visible photons is combined with the system specifications (pixel size, image reading time) in order to characterize (from a signal-to-noise ratio aspect) an X-Ray imaging system integrating a delayed luminescence property. The imaging plate and associated luminescent material are specified by their minimum X-Ray absorption and conversion gain. The Gudden-Pohl effect, or Electrically Stimulated Luminescence (ESL) is experimentally studied and quantified under X-Ray excitation in ZnCdS: Cu, Al materials. An original UV sensitization technique opens us the way to highly reproducible results and large sensitivity. The obtained information storage time in the material is compatible with a delayed image reading. These results allow the achievement of an X-Ray imaging demonstrator integrating the ESL imaging plate, an intensified CCD sensor and the sensitization technique. First images are obtained. Further conception of real dimension X-Ray imaging system for mammography is described. (author) [fr

A facile synthesis approach and impact of shell formation on morphological structure and luminescent properties of aqueous dispersible NaGdF{sub 4}:Yb/Er upconversion nanorods

Energy Technology Data Exchange (ETDEWEB)

Ansari, Anees A., E-mail: aneesaansari@gmail.com [King Saud University, King Abdullah Institute for Nanotechnology (Saudi Arabia); Yadav, Ranvijay; Rai, S. B. [Banaras Hindu University, Department of Physics (India)

2016-12-15

A general facile synthesis approach was used for fabrication of highly emissive aqueous dispersible hexagonal phase upconversion luminescent NaGdF{sub 4}:Yb/Er nanorods (core NRs) through metal complex decomposition process. An inert NaGdF{sub 4} and porous silica layers were grafted surrounding the surface of each and every NRs to enhance their luminescence efficiency and colloidal dispersibility in aqueous environment. Optical properties in terms of band gap energy of core, core/shell, and silica-coated core/shell/SiO{sub 2} nanorods were observed to investigate the influence of surface coating, which was gradually decreased after surface coating because of increase crystalline size after growth of inert and silica shells. The inert shell formation before silica surface grafting, upconversion luminescence intensity was greatly improved by about 20 times, owing to the effective surface passivation of the seed core and, therefore, protection of Er{sup 3+} ion in the core from the nonradiative decay caused by surface defects. Moreover, after silica coating, core/shell nanorods shows strong upconversion luminescence property similar to the hexagonal upconversion core NRs. It is expected that these NaGdF{sub 4}:Yb/Er@NaGdF{sub 4}@SiO{sub 2} (core/shell/SiO{sub 2}) NRs including highly upconversion emissive and aqueous dispersible properties make them an ideal materials for various photonic-based potential applications such as in upconversion luminescent bioimaging, magnetic resonance imaging, and photodynamic therapy.

Development and measurement of luminescence properties of Ce-doped Cs2LiGdBr6 crystals irradiated with X-ray, γ-ray and proton beam

Science.gov (United States)

Jang, Jonghun; Kim, H. J.; Rooh, Gul; Kim, Sunghwan

2017-12-01

The effect of higher Ce-concentration on the luminescence and scintillation properties of Cs2LiGdBr6 single crystals are studied. We used the Bridgman method for the growth of Ce-doped Cs2LiGdBr6 single crystals. Luminescence properties of the grown crystals are measured by X-ray and proton excitations. We measured the pulse height and fluorescence decay time spectra of Cs2LiGdBr6:Ce3+ with a bi-alkali photo multiplier tube (PMT) under γ-ray excitation from 137Cs source. Improvements in the scintillation properties are observed with the increase of Ce-concentration in the lattice. Detailed procedure of the crystal growth is also discussed.

Spatially-resolved luminescence spectroscopy of CdSe quantum dots synthesized in ionic liquid crystal matrices

Energy Technology Data Exchange (ETDEWEB)

Magaryan, K.A., E-mail: xmagaros@gmail.com [Moscow State Pedagogical University, 29 Malaya Pirogovskaya Str., Moscow 119992 (Russian Federation); Mikhailov, M.A. [Moscow State Pedagogical University, 29 Malaya Pirogovskaya Str., Moscow 119992 (Russian Federation); Karimullin, K.R. [Moscow State Pedagogical University, 29 Malaya Pirogovskaya Str., Moscow 119992 (Russian Federation); Institute for Spectroscopy of RAS, 5 Fizicheskaya Str., Troitsk, Moscow 142190 (Russian Federation); E.K. Zavoyski Kazan Physical-Technical Institute of RAS, 10/7 Sibirski trakt Str., Kazan 420029 (Russian Federation); Knyazev, M.V.; Eremchev, I.Y. [Institute for Spectroscopy of RAS, 5 Fizicheskaya Str., Troitsk, Moscow 142190 (Russian Federation); Naumov, A.V. [Moscow State Pedagogical University, 29 Malaya Pirogovskaya Str., Moscow 119992 (Russian Federation); Institute for Spectroscopy of RAS, 5 Fizicheskaya Str., Troitsk, Moscow 142190 (Russian Federation); Vasilieva, I.A. [Moscow State Pedagogical University, 29 Malaya Pirogovskaya Str., Moscow 119992 (Russian Federation); Klimusheva, G.V. [Institute of Physics, NAS of Ukraine, 46 Prospect Nauki, Kiev 03028 (Ukraine)

2016-01-15

The paper is devoted to investigation of luminescence properties of new quantum dot (QD)-doped materials. We studied CdSe QDs (1.8 nm and 2.3 nm) grown inside of a liquid crystalline cadmium alcanoate matrix. Temperature dependence of parameters of fluorescence spectra obtained in a wide temperature range using epi-luminescence microscopy technique was analyzed. Spatially-resolved luminescence images were measured for the areas of the samples of 150×150 µm{sup 2}. Strong correlation between fluorescence spectra and sample structure was observed. - Highlights: • Glassy matrix with CdSe quantum dots inside fabricated in liquid crystalline mesophase. • Study of luminescence properties in a wide range of low temperatures. • Strong dependence of the luminescence spectra on spatial inhomogeneities. • Spatially-resolved luminescence imaging of quantum dots in liquid crystalline matrix.

Spatially-resolved luminescence spectroscopy of CdSe quantum dots synthesized in ionic liquid crystal matrices

International Nuclear Information System (INIS)

Magaryan, K.A.; Mikhailov, M.A.; Karimullin, K.R.; Knyazev, M.V.; Eremchev, I.Y.; Naumov, A.V.; Vasilieva, I.A.; Klimusheva, G.V.

2016-01-01

The paper is devoted to investigation of luminescence properties of new quantum dot (QD)-doped materials. We studied CdSe QDs (1.8 nm and 2.3 nm) grown inside of a liquid crystalline cadmium alcanoate matrix. Temperature dependence of parameters of fluorescence spectra obtained in a wide temperature range using epi-luminescence microscopy technique was analyzed. Spatially-resolved luminescence images were measured for the areas of the samples of 150×150 µm 2 . Strong correlation between fluorescence spectra and sample structure was observed. - Highlights: • Glassy matrix with CdSe quantum dots inside fabricated in liquid crystalline mesophase. • Study of luminescence properties in a wide range of low temperatures. • Strong dependence of the luminescence spectra on spatial inhomogeneities. • Spatially-resolved luminescence imaging of quantum dots in liquid crystalline matrix.

Cooperative loading of multisite receptors with lanthanide containers: an approach for organized luminescent metallopolymers.

Science.gov (United States)

Babel, Lucille; Guénée, Laure; Besnard, Céline; Eliseeva, Svetlana V; Petoud, Stéphane; Piguet, Claude

2018-01-14

Metal-containing (bio)organic polymers are materials of continuously increasing importance for applications in energy storage and conversion, drug delivery, shape-memory items, supported catalysts, organic conductors and smart photonic devices. The embodiment of luminescent components provides a revolution in lighting and signaling with the ever-increasing development of polymeric light-emitting devices. Despite the unique properties expected from the introduction of optically and magnetically active lanthanides into organic polymers, the deficient control of the metal loading currently limits their design to empirical and poorly reproducible materials. We show here that the synthetic efforts required for producing soluble multi-site host systems L k are largely overcome by the virtue of reversible thermodynamics for mastering the metal loading with the help of only two parameters: (1) the affinity of the luminescent lanthanide container for a single binding site and (2) the cooperative effect which modulates the successive fixation of metallic units to adjacent sites. When unsymmetrical perfluorobenzene-trifluoroacetylacetonate co-ligands (pbta - ) are selected for balancing the charge of the trivalent lanthanide cations, Ln 3+ , in six-coordinate [Ln(pbta) 3 ] containers, the explored anti-cooperative complexation processes induce nearest-neighbor intermetallic interactions twice as large as thermal energy at room temperature ( RT = 2.5 kJ mol -1 ). These values have no precedent when using standard symmetrical containers and they pave the way for programming metal alternation in luminescent lanthanidopolymers.

Optically stimulated luminescence of natural NaCl mineral from Dead Sea exposed to gamma radiation

International Nuclear Information System (INIS)

Roman L, J.; Cruz Z, E.; Pina L, Y. I.; Marcazzo, J.

2016-10-01

Luminescence properties such as radioluminescence, thermoluminescence and optically stimulated luminescence have been studied on natural sodium chloride (NaCl) for dosimetric purposes in retrospective dosimetry (Timar-Gabor et al., 2013; Druzhyna et al., 2016). In this work, the optically stimulated luminescence (Cw-OSL) emissions of natural salt minerals, collected from Dead Sea in summer of 2015, were studied. The Cw-OSL dose response of natural salt was analyzed in the range between 0.2 and 10 Gy gamma dose of "6"0Co. Samples exposed at 3 Gy exhibited good repeatability with a variation coefficient of 4.6%. The thermal stability of the Cw-OSL response was analyzed to different temperatures from 50 up to 250 degrees Celsius using a heating rate of 5 degrees Celsius. The results showed that the natural Dead Sea salt minerals could be applied as natural dosimeter of gamma radiation. (Author)

Optically stimulated luminescence of natural NaCl mineral from Dead Sea exposed to gamma radiation

Energy Technology Data Exchange (ETDEWEB)

Roman L, J.; Cruz Z, E. [UNAM, Instituto de Ciencias Nucleares, Ciudad Universitaria, 04510 Ciudad de Mexico (Mexico); Pina L, Y. I. [UNAM, Facultad de Ciencias, Ciudad Universitaria, 04510 Ciudad de Mexico (Mexico); Marcazzo, J., E-mail: jesus.roman@nucleares.unam.mx [Instituto de Fisica Arroyo Seco - UNICEN, Pinto 399, 7000 Tandil (Argentina)

2016-10-15

Luminescence properties such as radioluminescence, thermoluminescence and optically stimulated luminescence have been studied on natural sodium chloride (NaCl) for dosimetric purposes in retrospective dosimetry (Timar-Gabor et al., 2013; Druzhyna et al., 2016). In this work, the optically stimulated luminescence (Cw-OSL) emissions of natural salt minerals, collected from Dead Sea in summer of 2015, were studied. The Cw-OSL dose response of natural salt was analyzed in the range between 0.2 and 10 Gy gamma dose of {sup 60}Co. Samples exposed at 3 Gy exhibited good repeatability with a variation coefficient of 4.6%. The thermal stability of the Cw-OSL response was analyzed to different temperatures from 50 up to 250 degrees Celsius using a heating rate of 5 degrees Celsius. The results showed that the natural Dead Sea salt minerals could be applied as natural dosimeter of gamma radiation. (Author)

Luminescence properties of Si-capped β-FeSi{sub 2} nanodots epitaxially grown on Si(001) and (111) substrates

Energy Technology Data Exchange (ETDEWEB)

Amari, Shogo; Ichikawa, Masakazu [Department of Applied Physics, Graduate School of Engineering, The University of Tokyo, Bunkyo-ku, Tokyo 113-8656 (Japan); Nakamura, Yoshiaki, E-mail: nakamura@ee.es.osaka-u.ac.jp [Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama-cho, Toyonaka, Osaka 560-8531 (Japan); PRESTO, JST, 4-1-8 Honcho Kawaguchi, Saitama 332-0012 (Japan)

2014-02-28

We studied the luminescence properties of Si-capped β-FeSi{sub 2} nanodots (NDs) epitaxially grown on Si substrates by using photoluminescence (PL) and electroluminescence (EL) spectroscopies. Codepositing Fe and Si on ultrathin SiO{sub 2} films induced the self-assembly of epitaxial β-FeSi{sub 2} NDs. The PL spectra of the Si/β-FeSi{sub 2} NDs/Si structure depended on the crystal orientation of the Si substrate. These structures exhibited a broad PL peak near 0.8 eV on both Si(001) and (111) substrates. The PL intensity depended on the shape of the β-FeSi{sub 2} NDs. For the flat NDs, which exhibited higher PL intensity, we also recorded EL spectra. We explained the luminescence properties of these structures by the presence of nanostructured Si offering radiative electronic states in the Si cap layers, generated by nano-stressors for upper Si layer: the strain-relaxed β-FeSi{sub 2} NDs.

Spectrally shaped broadband study of up-conversion in Y2O3:Er3+

International Nuclear Information System (INIS)

Lytle, A.L.; Gagnon, E.; Tulchinsky, L.; Krebs, J.K.

2014-01-01

We present a novel scheme for studying up-conversion through excited state absorption (ESA) by using a broadband excitation source with spectral shaping capabilities. Up-conversion processes have typically been investigated using a single, narrowband excitation source, when the two steps of the process are coincident in frequency, which is often made possible by broadening mechanisms of the intermediate excited state manifolds. Thus, narrowband sources are limited in the systems they can excite and what material information they can provide. With broadband light, we are able to drive up-conversion with non-coincident frequencies as well. Finally, by windowing the spectrum, we determine the optimal excitation bandwidth for low-concentration (1%) Y 2 O 3 :Er 3+ nanocrystals. - Highlights: • Broadband excitation light is used to drive up-conversion in Y 2 O 3 :Er 3+ . • Broadband light excites all available transitions in the two-photon process. • A spectral shaping technique is used to alter the excitation frequencies present. • The optimal excitation bandwidth is measured by windowing the spectrum. • Broadband excitation reveals information inaccessible by narrowband sources

Luminescent properties of europium different-ligand complexes with cyclic. beta. -diketones and diantipyrylalkanes

Energy Technology Data Exchange (ETDEWEB)

Ul' yanova, T M; Gerasimenko, G N; Tishchenko, M A; Vitkun, R A [AN Ukrainskoj SSR, Odessa. Fiziko-Khimicheskij Inst.

1983-03-01

Using luminescence method different-ligand complexing of europium ions with diantipyrylalkanes and cyclic ..beta..-diketones: 2-acetyl- and 2-benzoyl-1.3-indandions, has been studied. The optimum conditions of the formation of different-ligand complexes and the ratio of components in it are determined. Effect of alien lanthanides and diantipyrylmethane derivatives on the luminescence intensity of europium complexes is clarified. A correlation between the ratio of the luminescence intensity bands of europium complexes and the values of oscillator strengths of supersensitive transitions of neodymium and erbium absorption bands is established.

Luminescent properties and quenching effects of Pr3+ co-doping in SiO2:Tb3+/Eu3+ nanophosphors

CSIR Research Space (South Africa)

Mhlongo, GH

2014-02-01

Full Text Available Luminescence properties of Pr(sup3+) single doped SiO2 and Pr(sup3+) co-doped SiO(sub2):Tb(sup3+)/Eu(sup3+) nanophosphors synthesized using sol–gel method were investigated. X-ray diffraction (XRD), and scanning electron microscope (SEM) were used...

Luminescence mechanisms of organic/inorganic hybrid organic light-emitting devices fabricated utilizing a Zn2SiO4:Mn color-conversion layer

International Nuclear Information System (INIS)

Choo, D.C.; Ahn, S.D.; Jung, H.S.; Kim, T.W.; Lee, J.Y.; Park, J.H.; Kwon, M.S.

2010-01-01

Zn 2 SiO 4 :Mn phosphor layers used in this study were synthesized by using the sol-gel method and printed on the glass substrates by using a vehicle solution and a heating process. Organic/inorganic hybrid organic light-emitting devices (OLEDs) utilizing a Zn 2 SiO 4 :Mn color-conversion layer were fabricated. X-ray diffraction data for the synthesized Zn 2 SiO 4 :Mn phosphor films showed that the Zn ions in the phosphor were substituted into Mn ions. The electroluminescence (EL) spectrum of the deep blue OLEDs showed that a dominant peak at 461 nm appeared. The photoluminescence spectrum for the Zn 2 SiO 4 :Mn phosphor layer by using a 470 nm excitation source showed that a dominant peak at 527 nm appeared, which originated from the 4 T 1 - 6 A 1 transitions of Mn ions. The appearance of the peak around 527 nm of the EL spectra for the OLEDs fabricated utilizing a Zn 2 SiO 4 :Mn phosphor layer demonstrated that the emitted blue color from the deep blue OLEDs was converted into a green color due to the existence of the color-conversion layer. The luminescence mechanisms of organic/inorganic hybrid OLEDs fabricated utilizing a Zn 2 SiO 4 :Mn color-conversion layer are described on the basis of the EL and PL spectra.

Temperature, stress, and annealing effects on the luminescence from electron-irradiated silicon

Science.gov (United States)

Jones, C. E.; Johnson, E. S.; Compton, W. D.; Noonan, J. R.; Streetman, B. G.

1973-01-01

Low-temperature photoluminescence spectra are presented for Si crystals which have been irradiated with high-energy electrons. Studies of isochronal annealing, stress effects, and the temperature dependences of the luminescence are used to discuss the nature of the luminescent transitions and the properties of defects. Two dominant bands present after room-temperature anneal of irradiated material are discussed, and correlations of the properties of these bands are made with known Si defects. A band between 0.8 and 1.0 eV has properties which are related to those of the divacancy, and a band between 0.6 and 0.8 eV has properties related to those of the Si-G15(K) center. Additional peaks appear in the luminescence after high-temperature anneal; the influence of impurities and the effects of annealing of these lines are discussed.

Additives and solvents-induced phase and morphology modification of NaYF{sub 4} for improving up-conversion emission

Energy Technology Data Exchange (ETDEWEB)

Zhuang, Jianle, E-mail: zhuangjianle@126.com [Guangdong Provincial Engineering Technology Research Center for Optical Agriculture, College of Materials and Energy, South China Agricultural University, Guangzhou 510642 (China); MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou 510275 (China); Yang, Xianfeng; Wang, Jing [MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou 510275 (China); Lei, Bingfu; Liu, Yingliang [Guangdong Provincial Engineering Technology Research Center for Optical Agriculture, College of Materials and Energy, South China Agricultural University, Guangzhou 510642 (China); Wu, Mingmei, E-mail: ceswmm@mail.sysu.edu.cn [MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou 510275 (China)

2016-01-15

Both cubic and hexagonal NaYF{sub 4} were synthesized in different reaction systems via hydro/solvo-thermal route. The effects of reaction temperature, solvents, and additives on the synthesis of NaYF{sub 4} have been studied in detail. It has been shown that phase transformation from cubic NaYF{sub 4} to hexagonal NaYF{sub 4} always occurred. The sequence of the ability for inducing the phase transformation was ethanol>H{sub 2}O>acetic acid. It is found that ethanol can not only facilitate the formation of hexagonal NaYF{sub 4} but also control the growth of the crystal. This is quite unusual for the growth of H-NaYF{sub 4}. The up-conversion emission properties of Yb/Er co-doped NaYF{sub 4} have also been investigated and the results demonstrated some general principles for improving up-conversion emission. - Graphical abstract: Additives and solvents can induce the phase transformation of NaYF{sub 4}, typically the use of organic sodium salt and ethanol. - Highlights: • The effect of additives and solvents on the synthesis of NaYF{sub 4} was studied in detail. • Ethanol can facilitate the formation of H-NaYF{sub 4} while acetic acid restrain it. • Three general principles for improving up-conversion emission were summarized.

Luminescence and photosensitivity of PbI2 crystals

International Nuclear Information System (INIS)

Novosad, S.S.; Novosad, I.S.; Matviishin, I.M.

2002-01-01

One studied effect of temperature treatment and storage conditions on spectra features of PbI 2 crystals grown by the Bridgman-Stockbarger method from salt additionally purified by directed crystallization. Spectra of X-ray luminescence, photoluminescence and thermostimulated luminescence were investigated within 85-295 K temperature range under stationary X-ray excitation and emission of N 2 -laser. One studied photoelectret properties of those crystals under 85 K. Luminescence of PbI 2 crystals with maximum within 595 nm region observed following their thermal annealing under 475-495 K temperature and typical for near-the-surface section of specimens may be caused by oxygen-containing centres [ru

The exploration and characterization of an orange emitting long persistent luminescence phosphor LiSr4(BO3)3:Eu2+

International Nuclear Information System (INIS)

Jin, Yahong; Hu, Yihua; Wu, Haoyi; Chen, Li; Wang, Xiaojuan

2016-01-01

An orange emitting long persistent phosphor LiSr 4 (BO 3 ) 3 :Eu 2+ was prepared successfully using a conventional solid state reaction method. The luminescent and persistent luminescence properties were studied using fluorescence spectra, decay curves, persistent luminescence spectra and thermoluminescence (TL) glow curves. The effects on the fluorescence and persistent luminescence properties by the dosage of Li 2 CO 3 were explored. The relationship between the Eu 2+ contents and persistent luminescence properties were studied. The optimal doping concentration of Eu 2+ was experimentally to be 1 mol%. The detailed processes and a possible mechanism were also discussed. - Highlights: • Li 2 CO 3 plays a critical role in producing persistent luminescence. • 40 % excess of Li 2 CO 3 makes the largest enhancement on persistent luminescence. • The optimal doping concentration of Eu 2+ was experimentally to be 1mol %. • Possible mechanism for persistent luminescence was discussed.

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)

Luminescence and energy transfer processes in rare earth compounds

International Nuclear Information System (INIS)

Vliet, J.P.M. van.

1989-01-01

In this thesis some studies are presented of the luminescence and energy transfer in compounds containing Eu 3+ , Pr 3+ and Gd 3+ ions. Ch. 2 deals with the energy migration in the system Gd 1 - xEu x(IO 3) 3. In ch 3 the luminescence properties of the Pr 3+ ion in the system La 1 - xPr xMgAl 1 10 1 9 are reported. Ch. 4 discusses the luminescence properties of alkali europium double tungstates and molybdates AEuW 20 8 and AEuMo 20 * (A + = alkali metal atom). The luminiscence and energy migration characteristics of the isostructural system LiGd 1 - xEu xF 4 and Gd 1 - xEu xNbO 4 are reported in ch. 5. In ch. 6 the mechanism of energy migration in (La,Gd)AlO 3 and (Gd,Eu)AlO 3 is discussed. Ch. 7 deals with the system Na 5(Gd,Eu) (WO 4) 4. In ch. 8 the luminescence and energy transfer properties of two europium tellurite anti-glass phases are reported. The two phases are Eu 1 . 7 9TeO x, which has a pseudotetragonal structure, and Eu 1 . 0 6TeO x, which has a monoclinic, ordered structure. (author). 201 refs.; 39 figs.; 8 tabs

Analyzing Rumors, Gossip, and Urban Legends through Their Conversational Properties

Science.gov (United States)

Guerin, Bernard; Miyazaki, Yoshihiko

2006-01-01

A conversational approach is developed to explain the ubiquitous presence of rumors, urban legends, and gossip as arising from their conversational properties rather than from side effects of cognitive processing or "effort after meaning." It is suggested that the primary function of telling rumors, gossip, and urban legends is not to impart…

Efficient green luminescence of terbium oxalate crystals: A case study with Judd-Ofelt theory and single crystal structure analysis and the effect of dehydration on luminescence

Science.gov (United States)

Alexander, Dinu; Joy, Monu; Thomas, Kukku; Sisira, S.; Biju, P. R.; Unnikrishnan, N. V.; Sudarsanakumar, C.; Ittyachen, M. A.; Joseph, Cyriac

2018-06-01

Design and synthesis of Lanthanide based metal organic framework is a frontier area of research owing to their structural diversity enabling specific applications. The luminescence properties of rare earths, tuned by the structural features of Ln-MOFs are investigated extensively. Rare earth oxalates which can be synthesized in a facile method, ensuring the structural features of MOFs with excellent photoluminescence characteristics deserves much attention. This work is the first time report on the single crystal structure and Judd-Ofelt (JO) theoretical analysis - their correlation with the intense and sharp green luminescence of Terbium oxalate crystals. The intense green luminescence observed for Terbium oxalate crystals for a wide range of excitation from DUV to visible region despite the luminescence limiting factors are discussed. The absence of concentration quenching and lifting up of forbidden nature of f-f transitions, allowing direct excitation of Terbium ions is analysed with the help of JO theory and single crystal structure analysis. The JO analysis predicted the asymmetry of Terbium sites, allowing the electric dipole transitions and from the JO intensity parameters, promising spectroscopic parameters - emission cross section, branching ratio, gain band width and gain coefficient of the material were calculated. The single crystal structure analysis revealed the asymmetry of Tb sites and structure of Terbium oxalate is formed by the hydrogen bonded stacking of overlapped six Terbium membered rings connected by the oxalate ligands. The molecularly thick layers thus formed on the crystal surface are imaged by the atomic force microscopy. The presence of water channels in the structure and the effect of lattice water molecules on the luminescence intensity are also investigated.

Examination of the picture properties of luminescence memory foils

International Nuclear Information System (INIS)

Ewert, U.; Heine, S.; Nockemann, C.; Stade, J.; Tillack, G.R.; Wessel, H.; Zscherpel, U.; Mattis, A.

1995-01-01

Luminescence memory foils are a new medium for radiography without films. They are known by the name of image plates or digital memory foils. The suitability of such systems for industrial radiography is examined. (orig.) [de

8 nm nanodiamonds as markers for 2 photon excited luminescent microscopy

International Nuclear Information System (INIS)

Kharin, A; Rogov, A; Bonacina, L; Geloen, A; Lysenko, V

2016-01-01

Structural and luminescent properties of stable suspensions of fluorescent nanodiamonds were investigated. Measurement of the effective hydrodynamic radius yields particles less than 30 nm diameter, while the TEM measurements made on the same particles shows average diameter about 8 nm. It was found that NDs have relatively low toxicity. Upon incubation, 3T3-L1 cells spontaneously take up nanodiamonds that uniformly distribute in cells cytoplasm. The possibility of fluorescent imaging using both single ore two-photon excitation was shown. (paper)

Cooperative up-conversion processes in SrAl{sub 4}O{sub 7}:Yb and SrAl{sub 4}O{sub 7}:Yb,Tb and their dependence on charge compensation by Na

Energy Technology Data Exchange (ETDEWEB)

Puchalska, M., E-mail: malgorzata.puchalska@chem.uni.wroc.pl [Faculty of Chemistry, University of Wroclaw, 14, F. Joliot-Curie Street, 50-383 Wroclaw (Poland); Zych, E. [Faculty of Chemistry, University of Wroclaw, 14, F. Joliot-Curie Street, 50-383 Wroclaw (Poland); Watras, A. [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, 2 Okólna Street, 50-422 Wrocław (Poland)

2017-03-15

A detailed analysis of the luminescence behaviour of Yb{sup 3+}-doped and Yb{sup 3+}-Tb{sup 3+} co-doped strontium aluminates powders: Sr{sub 1-x}Yb{sub x}Al{sub 4}O{sub 7} (x=0.002–0.07) and Sr{sub 1-x-y}Yb{sub x}Tb{sub y}Al{sub 4}O{sub 7} (x=0.03; y=0.002–0.02) were performed. The studies of singly doped samples show that direct excitation of Yb{sup 3+} by means of {sup 2}F{sub 7/2}-{sup 2}F{sub 5/2} absorption at 900–980 nm leads to Stokes Yb{sup 3+} emission in the range of 970–1130 nm as well as bluish-green Yb{sup 3+} cooperative luminescence (CL) whose energy doubles that of the NIR one. The effect of activator concentration and charge compensation through Na{sup +} co-doping on both Yb{sup 3+} emissions were also studied. It was found that Na{sup +} addition enhanced Stokes Yb{sup 3+} photoluminescence brightness, while the cooperative emission intensity appeared to be lower. In doubly Yb{sup 3+}-Tb{sup 3+} doped materials excitation at 980 nm led to cooperative sensitization of the Tb{sup 3+} {sup 5}D{sub 4} level giving rise to its green {sup 5}D{sub 4}→{sup 7}F{sub J} (J={sup 7}F{sub 6}-{sup 7}F{sub 3}) up-conversion luminescence with the dominant component around 542 nm. The cooperative energy transfer (CET) mechanism was proposed basing on the results obtained from emission and absorption spectra, decay kinetics as well as the dependence of UC luminescence intensity on NIR excitation power.

Mesoporous material grafted with luminescent molecules for the design of selective metal ion chemosensor

International Nuclear Information System (INIS)

Zhang Huidong; Zhang Ping; Ye Kaiqi; Sun Yinghui; Jiang Shimei; Wang Yue; Pang Wenqin

2006-01-01

Luminescent Schiff-base groups have been successfully grafted on the surface of mesoporous material MCM-48. The grafted Schiff-base groups were employed to prepare luminescent Schiff-base-Zn complex that was covalently bound to the MCM-48 surface. These luminescent mesoporous materials were characterized with X-ray, UV-VIS and emission spectroscopic methods. Experimental results demonstrated that MCM-48 modified with functional groups exhibited novel luminescent property. The chemosensing property of modified MCM-48 sample was investigated. It was demonstrated that the fluorescence of MCM-48 solid with Schiff-base groups could be completely quenched by Cu 2+ cation and this mesoporous material was suitable for sensing Cu 2+ cation in aqueous media

f-state luminescence of lanthanide and actinide ions in solution

International Nuclear Information System (INIS)

Beitz, J.V.

1993-01-01

Detailed studies of the luminescence of aquated Am 3+ are presented in the context of prior lanthanide and actinide ion work. The luminescing state of aquated Am 3+ is confirmed to be 5 D l based on observed emission and excitation spectra. The luminescence lifetime of Am 3+ in H 2 O solution is (22 ± 3) ns and (155 ± 4) ns in D 2 O solution at 295 K. Judd-Ofelt transition intensity theory qualitatively describes the observed Am 3+ relative integrated fluorescence intensities. Recent luminescence studies on complexed trivalent f-element ions in solution are reviewed as to the similarities and differences between lanthanide ion 4f state and actinide ion 5f state properties

Thermo-optical properties of optically stimulated luminescence in feldspars

DEFF Research Database (Denmark)

Poolton, N.R.J.; Bøtter-Jensen, L.; Johnsen, O.

1995-01-01

Optically stimulated luminescence processes in feldspars are subject to competing thermal enhancement and quenching processes: this article describes the thermal enhancement effects for orthoclase, albite and plagioclase feldspars. It is demonstrated that certain lattice vibrational modes can be ...

Investigation of InGaN/GaN laser degradation based on luminescence properties

Energy Technology Data Exchange (ETDEWEB)

Wen, Pengyan; Zhang, Shuming, E-mail: smzhang2010@sinano.ac.cn; Liu, Jianping; Li, Deyao; Zhang, Liqun; Sun, Qian; Tian, Aiqin; Zhou, Kun; Yang, Hui [Key Laboratory of Nanodevices and Applications, Chinese Academy of Sciences, Suzhou 215123 (China); Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123 (China); Zhou, Taofei [Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123 (China)

2016-06-07

Degradation of InGaN/GaN laser diode (LD) is investigated based on the luminescence properties. Gradual degradation of the LD is presented with the threshold current increase and the slope efficiency decrease. The cathodoluminescence and photoluminescence characterizations of the LD show a dislocation independent degradation of the active region under the ridge. Detailed studies on the temperature-dependent micro-photoluminescence and the electroluminescence indicate that the degradation of the LD is attributed to the generation of non-radiative recombination centers in the local multiple quantum well regions with lower indium content. The activation energy of the non-radiative recombination centers is about 10.2 meV.

Luminescence properties of LiPrxCe1-xP4O12

International Nuclear Information System (INIS)

Shalapska, T.; Stryganyuka, G.; Trotsc, D.; Demkiv, T.; Gektin, A.; Voloshinovskii, A.; Dorenbos, P.

2010-01-01

LiPr 1-x Ce x P 4 O 12 (x=0, 0.002, 0.02; 0.1) powder samples were prepared using the melt solution technique. Luminescent parameters of LiPr 1-x Ce x P 4 O 12 phosphors have been investigated under ultraviolet-vacuum ultraviolet (3-12 eV) synchrotron radiation and X-rays excitation at room and near liquid He temperatures. Excitation luminescence spectra of Ce 3+ emission, luminescent spectra and decay curves from the lower excited state levels of the 4f 1 5d 1 and 5d 1 electronic configuration of the Pr 3+ and Ce 3+ , respectively, clearly indicate energy transfer from Pr 3+ to Ce 3+ . Energy migration proceeds via the Pr-sublattice followed by nonradiation transfer from Pr 3+ to Ce 3+ ions.

Defect-Induced Luminescence of a Self-Activated Borophosphate Phosphor

Science.gov (United States)

Han, Bing; Liu, Beibei; Dai, Yazhou; Zhang, Jie

2018-05-01

A self-activated borophosphate phosphor Ba3BPO7 was prepared via typical solid-state reaction in thermal-carbon reduction atmosphere. The structural and luminescence properties were investigated using x-ray powder diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, and photoluminescence spectroscopy. Upon excitation with ultraviolet (UV) light, the as-prepared phosphor shows bright greenish-yellow emission with a microsecond-level fluorescence lifetime, which could result from the oxygen vacancies produced in the process of solid-state synthesis. The possible luminescence mechanism is proposed. Through the introduction of defects in the host, this work realizes visible luminescence in a pure borophosphate compound that does not contain any rare earth or transition metal activators, so it is helpful to develop defect-related luminescent materials in view of energy conservation and environmental protection for sustainable development.

Construction of order mesoporous (Eu–La)/ZnO composite material and its luminescent characters

Energy Technology Data Exchange (ETDEWEB)

Bao, Na; Liu, Yu; Li, Zi-Wei [School of Chemistry & Environmental Engineering, Changchun University of Science and Technology, Changchun 130022 (China); Yu, Hui, E-mail: yh2001101@163.com [School of Chemistry & Environmental Engineering, Changchun University of Science and Technology, Changchun 130022 (China); Bai, Hao-tian [School of Chemistry & Environmental Engineering, Changchun University of Science and Technology, Changchun 130022 (China); Xia, Long, E-mail: xialong_aron@163.com [School of Materials Science and Engineering, Harbin Institute of Technology at Weihai, Weihai 264209 (China); Feng, Da-wei [Changchun University of Science and Technology Science Park, Changchun 130022 (China); Guangdong College of Business and Technology, Zhaoqing 526020 (China); Zhang, Hong-bo; Dong, Xiang-ting; Wang, Tian-yang; Han, Ji; Wu, Rong-yi; Zhang, Qi [School of Chemistry & Environmental Engineering, Changchun University of Science and Technology, Changchun 130022 (China)

2016-09-15

For the first time, the order mesoporous zinc oxide was synthesized by a soft template synthesis method. The Eu and La phosphate were introduced into the prepared mesoporous zinc oxide by the high temperature solid phase method, and got the mesoporous rare earth/zinc oxide composite materials. The luminescence characters of the materials were studied. The influences of La to Eu luminescent properties had been studied, and the optimum proportion of Eu and La was discussed. The influences of La and Eu to ZnO luminescence properties were also been studied. La phosphate had the large influence to Eu luminescent. ZnO had a strong emission peak at 469 nm, which overlapped with the {sup 7}F{sub 0}–{sup 5}D{sub 2} transition excitation peak of Eu at 465 nm. It indicated that the effective energy transfer happened between ZnO and Eu, which strongly enhanced the luminescence intensity of Eu. At the same time, the Eu and La phosphates could regulate the defect density of ZnO, which could regulate the luminescent intensity of ZnO, and realized the adjustment of luminescent color between green and red light.

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)

Luminescence properties of Ce3+-activated alkaline earth silicon nitride M2Si5N8 (M = Ca, Sr, Ba) materials

NARCIS (Netherlands)

Li, Y.Q.; With, de G.; Hintzen, H.T.J.M.

2006-01-01

The luminescence properties of Ce3+, Li+ or Na+ co-doped alkaline-earth silicon nitride M2Si5N8 (M=Ca, Sr, Ba) are reported. The solubility of Ce3+ and optical properties of M2-2xCexLixSi5N8 (x0.1) materials have been investigated as function of the cerium concentration by X-ray powder diffraction

Optical wavelength conversion by cross-phase modulation of data signals up to 640 Gb/s

DEFF Research Database (Denmark)

Galili, Michael; Oxenløwe, Leif Katsuo; Mulvad, Hans Christian Hansen

2008-01-01

In this paper, all-optical wavelength conversion by cross-phase modulation in a highly nonlinear fiber is investigated. Regenerative properties of the wavelength converter are demonstrated, and the effect of adding Raman gain to enhance the performance of the wavelength converter is shown. The wa....... The wavelength conversion scheme is demonstrated at the record-high bit rate of 640 Gb/s.......In this paper, all-optical wavelength conversion by cross-phase modulation in a highly nonlinear fiber is investigated. Regenerative properties of the wavelength converter are demonstrated, and the effect of adding Raman gain to enhance the performance of the wavelength converter is shown...

Luminescence properties of novel red-emitting phosphor InNb1-xPxO4:Eu3+ for white light emitting-diodes

Directory of Open Access Journals (Sweden)

Tang An

2015-06-01

Full Text Available InNb1-xPxO4:Eu3+ red phosphors were synthesized by solid-state reaction and their luminescence properties were also studied through photoluminescence spectra. The excitation and emission spectra make it clear that the as-prepared phosphors can be effectively excited by near-ultraviolet (UV 394 nm light and blue 466 nm light to emit strong red light located at 612 nm, due to the Eu3+ transition of 5D0 → 7F2. The luminescence intensity is dependent on phosphorus content, and it achieves the maximum at x = 0.4. Excessive phosphorus in the phosphors can result in reduction of luminescence intensity owing to concentration quenching.With the increasing content of phosphorus, the phosphors are prone to emit pure red light. This shows that the InNb1.6P0.4O4:0.04Eu3+ phosphor may be a potential candidate as a red component for white light emitting-diodes.

Luminescence and circularly polarized luminescence of macrocyclic Eu(III) and Tb(III) complexes embedded in xerogel and sol-gel SiO2 glasses

International Nuclear Information System (INIS)

Morita, M.; Rau, D.; Kai, T.

2002-01-01

Luminescence, time-resolved luminescence, circularly polarized luminescence (CPL) and decay profiles of Ln(III)(15-crownether-5) (Ln=Ce, Sm, Eu, Tb) and Tb(III)-(R),(S)-cyclen derivative complexes doped in xerogel and sol-gel silica glasses are measured at temperatures down to 10 K to characterize luminescence properties and the electronic structure in the excited states. Luminescence spectral profiles and calculation of crystal field parameters (B 0 (2) ,B 2 (2) ) in the 5 D 0 → 7 F J (J=1,2) transition give evidence of the fact that the pentagonal and planar structure of Eu(III) (15-crownether-5) does hold in xerogel and sol-gel glasses prepared at temperatures below 100 deg. C. As annealing temperatures are increased from 80 deg. C to 750 deg. C, Eu(III) complexes in sol-gel glasses are found to decompose gradually to SiO 2 :Eu 3+ . Tb(III)-(R) and (S)-cyclen derivative complexes in xerogel reveal at room temperature and 10 K sharp CPL spectra with luminescence dissymmetry factors g lum =-0.1 and 0.1, respectively. These complexes doped in sol-gel glasses represent luminescence characteristics of rare earth ions encapsulated in the nano-porous host

Spectral luminescence and geochemistry of coral aragonite: Effects of whole-core treatment

NARCIS (Netherlands)

Nagtegaal, R.; Grove, C.A.; Kasper, S.; Zinke, J.; Brummer, G.J.A.

2012-01-01

Luminescent and geochemical properties of coral skeletons are increasingly used for time-series analysis to resolve past and ongoing changes in environmental and climatic conditions. Corals also contain non-skeletal matter which not only quenches luminescence but is also reported to compromise

Spectral properties and anti-Stokes luminescence of TeO2-BaF2:Ho3+, Ho3+/Yb3+ ceramics and glass excited by 1.9-μm radiation of a Tm:LiYF4 laser

Science.gov (United States)

Savikin, A. P.; Egorov, A. S.; Budruev, A. V.; Perunin, I. Yu.; Krasheninnikova, O. V.; Grishin, I. A.

2017-07-01

We demonstrate the up-conversion of Tm:LiYF4 infrared (IR) laser radiation with 1908-nm wavelength into visible light with a spectral maximum at 650 nm by ceramics with a composition of (100 - x)TeO2- xBaF2 - 1 wt % HoF3- yYbF3, where x = 20, 30, or 40 mol % and y = 0 or 0.5 wt %. The samples of 60TeO2-40BaF2 - 1 wt % HoF3 - 0.5 wt % YbF3 exhibited anti-Stokes luminescence at a threshold radiation power density of 1.0-1.5 W cm-2.

Enhanced Power Conversion Efficiency of Perovskite Solar Cells with an Up-Conversion Material of Er3+-Yb3+-Li+ Tri-doped TiO2.

Science.gov (United States)

Zhang, Zhenlong; Qin, Jianqiang; Shi, Wenjia; Liu, Yanyan; Zhang, Yan; Liu, Yuefeng; Gao, Huiping; Mao, Yanli

2018-05-11

In this paper, Er 3+ -Yb 3+ -Li + tri-doped TiO 2 (UC-TiO 2 ) was prepared by an addition of Li + to Er 3+ -Yb 3+ co-doped TiO 2 . The UC-TiO 2 presented an enhanced up-conversion emission compared with Er 3+ -Yb 3+ co-doped TiO 2 . The UC-TiO 2 was applied to the perovskite solar cells. The power conversion efficiency (PCE) of the solar cells without UC-TiO 2 was 14.0%, while the PCE of the solar cells with UC-TiO 2 was increased to 16.5%, which presented an increase of 19%. The results suggested that UC-TiO 2 is an effective up-conversion material. And this study provided a route to expand the spectral absorption of perovskite solar cells from visible light to near-infrared using up-conversion materials.

Synthesis and luminescent properties of two Schiff-base boron complexes

Energy Technology Data Exchange (ETDEWEB)

Hou Qiufei [Key Lab for Supramolecular Structure and Materials of Ministry of Education, Jilin University, 2699 Qianjin Street, Changchun 130012 (China); Zhao Liyan [Key Lab for Supramolecular Structure and Materials of Ministry of Education, Jilin University, 2699 Qianjin Street, Changchun 130012 (China); Zhang Hongyu [Key Lab for Supramolecular Structure and Materials of Ministry of Education, Jilin University, 2699 Qianjin Street, Changchun 130012 (China); Wang Yue [Key Lab for Supramolecular Structure and Materials of Ministry of Education, Jilin University, 2699 Qianjin Street, Changchun 130012 (China); Jiang Shimei [Key Lab for Supramolecular Structure and Materials of Ministry of Education, Jilin University, 2699 Qianjin Street, Changchun 130012 (China)]. E-mail: smjiang@jlu.edu.cn

2007-10-15

Schiff bases N,N'-o-phenylenebis (salicylideneimine) (H{sub 2} L{sup 1} ), N,N'-p-phenylenebis (salicylideneimine) (H{sub 2} L{sup 2} ) and their corresponding boron complexes (BF{sub 2}){sub 2} L{sup 1} (BF{sub 2}){sub 2} L{sup 2} were synthesized, respectively. The two boron complexes have been characterized by {sup 1}H NMR, mass spectrometry and elemental analysis, while the luminescent properties of them were investigated with UV-VIS spectroscopy and photoluminescence spectroscopy. Then the three-layer devices [ITO/NPB (60 nm)/(BF{sub 2}){sub 2} L{sup 1} (50 nm)/Alq3 (20 nm)/LiF (1 nm)/Al (200 nm)] (device I) and [ITO/NPB (60 nm)/(BF{sub 2}){sub 2} L{sup 2} (50 nm)/Alq3 (20 nm)/LiF (1 nm)/Al (200 nm)] (device II) were fabricated by vacuum deposition. These two devices both exhibited blue green emission at 500 nm, but showed different luminances and efficiencies.

Viscometric and Pulsed Photostimulated Luminescence Properties of Irradiated Glutinous Rice

International Nuclear Information System (INIS)

Yang, J.S.; Yi, S.D.; Chang, K.S.; Oh, M.J.

2004-01-01

This study was carried out to establish a method for the detection of irradiated glutinous rice by measuring pulsed photostimulated luminescence (PPSL) and viscometric properties. Viscosity was determined using a Brookfield DV-III rotation viscometer at 3 deg. C and measured at 30, 60, 90, 120, 150, 180, and 210 rpm. All irradiated samples indicated a decrease in viscosity with increasing stirring speeds (rpm) and irradiation doses. Treatments with 2∼5 kGy significantly decreased the viscosity. The photon counts of the irradiated glutinous rice were measured by PPSL and the photon counts of the non-irradiated and irradiated glutinous rice measured immediately after irradiation exhibited an increase with increasing irradiation dose. The photon counts of irradiated glutinous rice almost disappeared with the lapse of time when stored under normal room conditions, but was still possible to detect after 12 months of darkroom storage. Consequently, these results indicate that the detection of irradiated glutinous rice is possible by both viscometric and PPSL methods

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)

Up-conversion in an Er-containing nanocomposite and microlasers based on it

Science.gov (United States)

Sobeshchuk, N. O.; Denisyuk, I. Yu.

2017-06-01

The results of an investigation of three-dimensional polymer microcavities doped with inorganic luminescent particles are presented. Microlasers in the form of rectangular parallelepipeds were fabricated based on the SU8 2025 photoresist by means of compact UV lithography. Luminescent particles containing erbium oxide were obtained by low-temperature synthesis of the corresponding chlorides in a nonaqueous medium. The obtained spectra confirm the presence of a narrowband laser radiation exhibiting a Stokes shift.

Luminescent Metal Nanoclusters for Potential Chemosensor Applications

Directory of Open Access Journals (Sweden)

Muthaiah Shellaiah

2017-12-01

Full Text Available Studies of metal nanocluster (M-NCs-based sensors for specific analyte detection have achieved significant progress in recent decades. Ultra-small-size (<2 nm M-NCs consist of several to a few hundred metal atoms and exhibit extraordinary physical and chemical properties. Similar to organic molecules, M-NCs display absorption and emission properties via electronic transitions between energy levels upon interaction with light. As such, researchers tend to apply M-NCs in diverse fields, such as in chemosensors, biological imaging, catalysis, and environmental and electronic devices. Chemo- and bio-sensory uses have been extensively explored with luminescent NCs of Au, Ag, Cu, and Pt as potential sensory materials. Luminescent bi-metallic NCs, such as Au-Ag, Au-Cu, Au-Pd, and Au-Pt have also been used as probes in chemosensory investigations. Both metallic and bi-metallic NCs have been utilized to detect various analytes, such as metal ions, anions, biomolecules, proteins, acidity or alkalinity of a solution (pH, and nucleic acids, at diverse detection ranges and limits. In this review, we have summarized the chemosensory applications of luminescent M-NCs and bi-metallic NCs.

Luminescence properties of pure and Eu-doped SrI{sub 2} crystals purified by a “Liquinert” process and grown by vertical Bridgman method

Energy Technology Data Exchange (ETDEWEB)

Kawai, Taketoshi, E-mail: buri@p.s.osakafu-u.ac.jp [Osaka Prefecture University, Gakuen-cho 1-1, Naka-ku, Sakai, Osaka 599-8531 (Japan); Sakuragi, Shiro; Hashimoto, Satoshi [Union Materials Inc. 1640 Oshido, Tone-machi, Ibaraki 300-1602 (Japan)

2016-08-15

We have prepared high quality crystals of pure SrI{sub 2} and Eu-doped SrI{sub 2} by our original “Liquinert” process and investigated their luminescence properties. Under the excitation with the 193 nm light of an ArF excimer laser, which corresponds to the wavelength above the bandgap of SrI{sub 2} bulk crystals, the pure and Eu doped SrI{sub 2} crystals exhibit no luminescence band related to defects or impurities around 560 nm. This fact indicates that the crystals prepared by the “Liquinert” process contain lower defects and/or impurities. When the Eu-doped SrI{sub 2} crystals are excited with the 325 nm light of a He–Cd laser, only the luminescence band due to the 5d→4f transition in the Eu{sup 2+} ions is observed around 425 nm. The 425 nm band observed at a forward configuration exhibits the shift to the longer wavelength side and the decrease of the luminescence intensity with increasing Eu concentration. The Eu concentration dependences of the peak wavelength and luminescence intensity are simulated on the basis of a simple self-absorption model. - Highlights: • Our original “Liquinert” process allows us to prepare high quality crystals of SrI{sub 2}. • No luminescence band related with impurities and/or defects is observed. • The 425 nm luminescence bands due to Eu{sup 2+} ions are affected by a self-absorption. • A simple self-absorption model reproduces the changes of the 425 nm bands.

Synthesis, structure and luminescence properties of lanthanide complex with a new tetrapodal ligand featuring salicylamide arms

International Nuclear Information System (INIS)

Song Xueqin; Wen Xiaoguang; Liu Weisheng; Wang Daqi

2010-01-01

A new tetrapodal ligand 1,1,1-tetrakis{[(2'-(2-furfurylaminoformyl))phenoxyl]methyl}methane (L) has been prepared and their coordination chemistry with Ln III ions has been investigated. The structure of {[Ln 4 L 3 (NO 3 ) 12 ].H 2 O} ∞ (Ln=Nd, Eu)] shows the binodal 4,3-connected three-dimensional interpenetration coordination polymers with topology of a (8 6 ) 3 (8 3 ) 4 notation. [DyL(NO 3 ) 3 (H 2 O) 2 ].0.5CH 3 OH and [ErL(NO 3 ) 3 (H 2 O) (CH 3 OH)].CH 3 COCH 3 is a 1:1 mononuclear complex with interesting supramolecular features. The structure of [NdL(H 2 O) 6 ].3ClO 4 .3H 2 O is a 2:1 mononuclear complex which further self-assembled through hydrogen bond to form a three-dimensional supramolecular structures. The result presented here indicates that both subtle variation of the terminal group and counter anions can be applied in the modulation of the overall molecular structures of lanthanide complex of salicylamide derivatives due to the structure specialties of this type of ligand. The luminescence properties of the Eu III complex are also studied in detail. - Grapical Abstract: We present here a series of zero- to three-dimensional lanthanide coordination structures and luminescence properties of Eu(III) complex of a new tetrapodal ligand.

Structural, vibrational and luminescence properties of the (1−x)CaWO{sub 4}−xCdWO{sub 4} system

Energy Technology Data Exchange (ETDEWEB)

Taoufyq, A. [Institut Matériaux Microélectronique et Nanosciences de Provence, Aix Marseille Université, CNRS, Université de Toulon, IM2NP UMR 7334, 83957, La Garde (France); Laboratoire Matériaux et Environnement LME, Faculté des Sciences, Université Ibn Zohr, BP 8106, Cité Dakhla, Agadir, Maroc (Morocco); CEA/DEN, Département d’Études des Réacteurs, Laboratoire Dosimétrie Capteurs Instrumentation, CEA Cadarache, 13108, Saint-Paul-lez-Durance (France); Société CESIGMA, Signals and Systems, 1576 Chemin de La Planquette, 83130 La Garde (France); Guinneton, F.; Valmalette, J-C.; Arab, M. [Institut Matériaux Microélectronique et Nanosciences de Provence, Aix Marseille Université, CNRS, Université de Toulon, IM2NP UMR 7334, 83957, La Garde (France); Benlhachemi, A.; Bakiz, B. [Laboratoire Matériaux et Environnement LME, Faculté des Sciences, Université Ibn Zohr, BP 8106, Cité Dakhla, Agadir, Maroc (Morocco); Villain, S. [Institut Matériaux Microélectronique et Nanosciences de Provence, Aix Marseille Université, CNRS, Université de Toulon, IM2NP UMR 7334, 83957, La Garde (France); and others

2014-11-15

In the present work, we investigate the structural, microstructural, vibrational and luminescence properties of the system (1−x)CaWO{sub 4}−xCdWO{sub 4} with x ranging between 0 and 1. Polycrystalline samples were elaborated using a coprecipitation technique followed by thermal treatment at 1000 °C. The samples were then characterized using X-ray diffraction, scanning electron microscopy, Raman spectroscopy and luminescence analyses. X-ray diffraction profile analyses using Rietveld method showed that two kinds of solid solutions Ca{sub 1−x}Cd{sub x}WO{sub 4} having scheelite and wolframite structures, with respectively tetragonal and monoclinic crystal cells, were observed, with a biphasic system for compositions x=0.6 and 0.7. The scanning electron microscopy experiments showed a complex evolution of morphologies and crystallite sizes as x increased. The vibration modes of Raman spectra were characteristic of composition-dependent disordered solid solutions with decreasing wavenumbers as x increased. Luminescence experiments were performed under UV-laser light irradiation. The energies of emission bands increased linearly with cadmium composition x. The integrated intensity of luminescence reached a maximum value for the substituted wolframite phase with composition x=0.8. - Graphical abstract: Luminescence on UV excitation (364.5 nm) of (1−x)CaWO{sub 4−x}CdWO{sub 4} system, elaborated from coprecipitation technique at 1000 °C, with 0luminescence intensity for the composition x=0.8. - Highlights: • Solid solutions Ca{sub 1−x}Cd{sub x}WO{sub 4} are elaborated from coprecipitation technique. • The structures of two types of solid solutions are refined using Rietveld method. • A maximum of luminescence is obtained for an intermediate composition x=0.8.

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.

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.

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

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.

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

Luminescent properties of Al{sub 2}O{sub 3}: Tb powders; Propiedades luminiscentes de polvos de Al{sub 2}O{sub 3}: Tb

Energy Technology Data Exchange (ETDEWEB)

Esparza G, A.E.; Garcia, M.; Falcony, C.; Azorin N, J. [CICATA-IPN, Legaria 694, Col. Irrigacion, 11500 Mexico D.F. (Mexico)

2000-07-01

In this work the photo luminescent and cathode luminescent characteristics of aluminium oxide (Al{sub 2}O{sub 3}) powders impurified with terbium (Tb) were studied for their use in dosimetry. The optical, structural, morphological characteristics of the powders as function of variation in the impurity concentration and the annealing temperature will be presented. As regards the optical properties of powders (photoluminescence and cathode luminescence) it was observed a characteristic emission associated with radiative transitions between electron energy levels of terbium, the spectra associated with this emission consists of several peaks associated with such transitions. In the structural and morphological characterization (X-ray diffraction and scanning electron microscopy) it was appreciated that in accordance the annealing temperature of powders is augmented it is evident the apparition of certain crystalline phases. The results show that this is a promissory material for radiation dosimetry. (Author)

Influence of surface functionalization on structural and photo-luminescence properties of CeF{sub 3}:Tb nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Ansari, Anees A., E-mail: aneesaansari@gmail.com

2017-07-01

Graphical abstract: We designed highly aqueous dispersible CeF{sub 3}:Tb@LaF{sub 3}@SiO{sub 2} nanoparticles. The epitaxial growth of inert LaF{sub 3} shell and further amorphous silica, respectively, enhanced their optical and luminescence properties, which is highly usable for luminescent biolabeling, and optical bio-probe etc. - Abstract: Highly luminescent and aqueous soluble CeF{sub 3}:Tb (core),CeF{sub 3}:Tb@LaF{sub 3}(core/shell) and CeF{sub 3}:Tb@LaF{sub 3}@ SiO{sub 2} (core/shell/Si) nanoparticles(NPs) with mean particle size 12 nm were prepared by co-precipitation method at low temperature. X-ray diffraction pattern verified the phase purity, high crystallinity of hexagonal structure. The TEM image and SAED pattern revealed the single phase polycrystalline nature, well-dispersed irregular shaped hexagonal structure. FTIR spectra show the characteristic infrared peaks of silica, it suggests the successful silica surface coating around the core/shell NPs. The excitation and emission intensity of core/shell NPs were remarkably increased then their counterpart core NPs. It implies that a significant amount of nonradiative transition centers existing on the surface of core NPs has been eliminated due to the formation of passivated LaF{sub 3} layer. The silica surface modification over the core/shell NPs strikingly enhanced the solubility character in an aqueous environment.

An optically stimulated luminescence study of porcelain related to radiation dosimetry

DEFF Research Database (Denmark)

Poolton, N.R.J.; Bøtter-Jensen, L.; Jungner, H.

1995-01-01

Stokes and anti-Stokes shifted in energy. Glazing is shown in some cases to be considerably more sensitive as a radiation dosemeter than the main porcelain ceramic. By comparison with the properties of artifical phosphors, the principal luminescent matrix is identified as being Al2O3......This article describes the essential features regarding the photo-stimulated luminescence of porcelain: both the main ceramic and glazing materials are studied. In each case, radiation dose dependent signals are observed, superimposed on dose independent luminescence transitions that are both...

Metal-enhanced fluorescence of mixed coumarin dyes by silver and gold nanoparticles: Towards plasmonic thin-film luminescent solar concentrator

Energy Technology Data Exchange (ETDEWEB)

El-Bashir, S.M., E-mail: elbashireg@yahoo.com [Department of Physics and Astronomy, Science College, King Saud University, Riyadh, KSA (Saudi Arabia); Department of Physics Faculty of Science, Benha University (Egypt); Barakat, F.M.; AlSalhi, M.S. [Department of Physics and Astronomy, Science College, King Saud University, Riyadh, KSA (Saudi Arabia)

2013-11-15

Poly(methyl methacrylate) (PMMA) nanocomposite films doped with mixed coumarin dyestuffs and noble metal nanoparticles (60 nm silver and 100 nm gold) were prepared by spin coating technique. The effect of silver and gold nanoparticles on the film properties was studied by Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), transmission electron microscopy (TEM), scanning electron microscopy (SEM), UV–vis absorption and fluorescence spectroscopy measurements. DSC measurements indicated the increase of the glass transition temperature of the films by increasing nanogold concentration, recommending their promising thermal stability towards hot climates. It was found that the fluorescence signals of the mixed coumarin dyes were amplified by 5.4 and 7.15 folds as a result of metal enhanced fluorescence (MEF). The research outcomes offered a potential application of these films in solar energy conversion by plasmonic thin film luminescent solar concentrator (PTLSC). -- Graphical abstract: Plasmonic thin film luminescent solar concentrators. Highlights: • Metal enhanced fluorescence was achieved for mixed coumarin dyes doped in PMMA nanocomposite films. • The amplification of the fluorescence signals is dependent on the concentration of silver and gold nanoparticles. • These films is considered as potential candidates for plasmonic thin film luminescent solar concentrators (PTLSCs)

Investigation of electro-optical properties for electrochemical luminescence device with a new electrode structure

Science.gov (United States)

Ok, Jung-Woo; Pooyodying, Pattarapon; Anuntahirunrat, Jirapat; Sung, Youl-Moon

2018-04-01

In this paper, we investigate electrochemical luminescent (ECL) device with a new structure and the ECL cell device with proposed electrode configuration works reliably at AC voltage. In particular, the conventional ECL cell has counter electrodes in which a cathode and an anode are opposed to each other, whereas the proposed structure has parallel electrodes in which a cathode and an anode are arranged on a single substrate. The proposed electrode configuration has a structural feature that electric short-circuiting is less likely to occur during bending than the conventional electrode configuration. The electro-optical characteristics of the new electrode configuration such as the current density, the light emission intensity, and the time evolution of the emission are investigated. The proposed ECL device exhibited higher light emitting efficiency than the conventional structure. Especially, at AC operation mode, the new structure showed the distinctive luminescence characteristic which is combined the first luminescence near the surface of electrode with the delayed second luminescence near the center of between electrodes. It was closely related to the behavior of luminescent particles. The proposed the ECL cell structure is expected to be utilized as a flexible display device by taking advantage of its characteristics and practicality.

Versatile lanthanide-azide complexes with azide/carboxylate/hydroxy mixed bridged chain exhibiting magnetic and luminescent properties

International Nuclear Information System (INIS)

Wang Haichao; Xue Min; Guo Qian; Zhao Jiongpeng; Liu Fuchen; Ribas, Joan

2012-01-01

Two new lanthanide-azide complexes, [Ln 2 (N 3 )(isonic) 2 (OH) 3 (Hisonic)(H 2 O)] n (Ln=Yb for 1 and Tb for 2, isonic=isonicotinate), were obtained in hydrothermal condition. X-ray diffraction analysis indicated the two complexes are isomorphic chain structure in which the Ln III ions are mixed bridged by the azide anions, hydroxyl anions and carboxylate groups of the isonicotinate ligands. Further studies indicated weak antiferromagnetic interactions between the Ln III ions in 1 and 2, and complex 2 exhibit green sensitized Luminescent character of Tb III ion. - Graphical abstract: Two new 1D lanthanide-azide complexes, [Ln 2 (N 3 )(isonic) 2 (OH) 3 (Hisonic)(H 2 O)] n (Ln=Yb III for 1 and Tb III for 2, isonic=isonicotinate), were synthesized by hydrothermal reaction and exhibit interesting magnetism and fluorescence properties. Highlights: ► The research provided a new method for synthesizing lanthanide-azide complexes. ► The complexes have an interesting azide/hydroxyl/carboxylate mixed bridged1D chain structure. ► The antiferromagnetic coupling between the complexes and 2 displays green luminescence.

Parametric study of up-conversion efficiency in Er-doped ceria nanoparticles under 780 nm excitation

International Nuclear Information System (INIS)

Shehata, N.; Kandas, I.; Samir, E.; Meehan, K.; Aldacher, M.

2016-01-01

This paper presents a new parametric study of the optical up-conversion process in ceria nanoparticles doped with erbium (Er-CeO 2 NPs). Under 780 nm excitation, both the possible transitions that occur between Er 3+ ions and up-conversion rate model simulation are presented. Ceria nanoparticles (CeO 2 NPs) doped with erbium are experimentally synthesized using chemical precipitation technique with post-annealing up to 900 °C with different weight ratios of erbium dopant. We found that the synthesized nanoparticles can emit both green and red emissions under 780 nm laser excitation via two-photon absorption mechanism. Then, the quantum efficiencies of both colored emissions are theoretically investigated with different parameters related to the optical conversion process and the studied material. In addition, this work offer suggested ranges for the optimum values of the studied parameters which could improve the quantum yield efficiency. Einstein coefficients for erbium hosted in ceria are discussed in details using Judd–Ofelt analysis. This promising study could be helpful in improving the up-conversion efficiency of Er-ceria nanoparticles for applications such as bio-imaging and optical-based sensors.

Preparation, characterization and luminescence of nanocrystalline Y2O3:Ho

International Nuclear Information System (INIS)

Biljan, Tomislav; Gajovic, Andreja; Meic, Zlatko; Mestrovic, Ernest

2007-01-01

Nanocrystalline Y 2 O 3 :Ho was synthesized by solution combustion method with ethylene glycol as fuel. Material was characterized using powder X-ray diffraction and transmission electron microscopy (TEM). X-ray diffraction and TEM showed that the material is nanostructured. Luminescence properties were studied using Raman spectrometers with excitation in near infrared (NIR) and visible regions. The visible and NIR luminescence spectra of nanocrystalline Y 2 O 3 :Ho show some important differences from those of bulk material. The convenience of using Raman instruments for studying luminescence of lanthanide ions is demonstrated

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.

Luminescent, magnetic and ferroelectric properties of noncentrosymmetric chain-like complexes composed of nine-coordinate lanthanide ions.

Science.gov (United States)

Li, Xi-Li; Chen, Chun-Lai; Xiao, Hong-Ping; Wang, Ai-Ling; Liu, Cai-Ming; Zheng, Xianjun; Gao, Li-Jun; Yang, Xiao-Gang; Fang, Shao-Ming

2013-11-21

Reaction of the chiral ligand (-)-4,5-pinenepyridyl-2-pyrazine (L) with Ln(hfac)3·2H2O precursors [hfac(-) = 1,1,1,5,5,5-hexafluoroacetylacetonate, Ln = Sm(3+) (1), Eu(3+) (2), Tb(3+) (3) and Dy(3+) (4)] in methanol solution led to the formation of four noncentrosymmetric lanthanide complexes with the general formula [Ln(hfac)3L]n·H2O. The single-crystal X-ray diffraction analyses revealed that they are isostructural and take a one-dimensional (1D) chain structure based on the Ln(hfac)3L repeating units, in which the nine-coordinate Ln(3+) ions reside in a tricapped trigonal prism (TTP) environment never reported in previous 1D chain lanthanide complexes. The investigations of their photophysical properties showed that complexes 1, and 3 exhibit characteristic emissions of Sm(3+), Eu(3+) and Tb(3+) ions with respective luminescent lifetime values of 0.065, 1.066 and 0.129 ms, while complex 4 does not display any emission. The different luminescent intensities and lifetimes among them were further discussed in detail. Moreover, the magnetic properties of complexes 1-4 were assessed with a special emphasis on the Dy(3+) complex 4. Alternating-current (ac) magnetic susceptibility measurements indicated that field-induced two-step slow magnetic relaxation processes were observed in 4, indicating the single-molecule magnet (SMM) behavior of 4. In addition, the noncentrosymmetric complexes 1-4 crystallizing in the same polar point group (Cs) exhibit both ferroelectric and nonlinear optical properties at room temperature. All these features make them multifunctional crystalline molecule materials.

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)

Luminescent properties of praseodymium in some fluorides

International Nuclear Information System (INIS)

Potapov, A.S.; Rodnyj, P.A.; Mikhrin, S.B.; Magunov, I.R.

2005-01-01

Influence of diverse factors on efficiency of the Pr 3+ cascade emission in BaF 2 : Pr and SrAlF 5 : Pr. The effect of the environment of the luminescence center on the mutual position of the lowest 5d and the 4f level 1 S 0 of Pr 3+ ion is considered. PrF 3 clustering in BaF 2 is observed at a high praseodymium concentration. The promising potential of magnesium as a charge compensator for praseodymium in SrAlF 5 is demonstrated [ru

Co-precipitation synthesis and upconversion luminescence ...

Indian Academy of Sciences (India)

Introduction. Researches of rare-earth-doped upconversion (UC) materials as fluorescent labels, temperature-sensing probes, solid-state lasers and new generation television screens have recently started to be considered1,2 due to their enhanced luminescent properties induced by the small size. UC process is the gener-.

On the correlation between annealing and variabilities in pulsed-luminescence from quartz

International Nuclear Information System (INIS)

Chithambo, M.L.

2006-01-01

Properties of luminescence lifetimes in quartz related to annealing between 500 and 900 deg. C have been investigated. The luminescence was pulse-stimulated at 470nm from sets of granular quartz annealed at 500, 600, 700, 800, and 900 deg. C. The lifetimes decrease with annealing temperature from about 42 to 33μs when the annealing temperature is increased from 500 to 900 deg. C. Luminescence lifetimes are most sensitive to duration of annealing at 600 deg. C, decreasing from 40.2+/-0.7μs by as much as 7μs when the duration of annealing is changed from 10 to 60min. However, at 800-900 deg. C lifetimes are essentially independent of annealing temperature at about 33μs. Increasing the exciting beta dose causes an increase in the lifetimes of the stimulated luminescence in the sample annealed at 800 deg. C but not in those annealed at either 500 or 600 deg. C. The temperature-resolved distribution of luminescence lifetimes is affected by thermal quenching of luminescence. These features may be accounted for with reference to two principal luminescence centres involved in the luminescence emission process

Negative luminescence and devices based on this phenomenon

International Nuclear Information System (INIS)

Ivanov-Omskii, V. I.; Matveev, B. A.

2007-01-01

Recent publications concerned with infrared emitters whose electrical modulation results in absorption of radiation detected as negative luminescence are reviewed. The main properties of the devices based on this phenomenon are analyzed

Negative luminescence and devices based on this phenomenon

Energy Technology Data Exchange (ETDEWEB)

Ivanov-Omskii, V I; Matveev, B. A. [Russian Academy of Sciences, Ioffe Physicotechnical Institute (Russian Federation)], E-mail: bmat@iropt3.ioffe.rssi.ru

2007-03-15

Recent publications concerned with infrared emitters whose electrical modulation results in absorption of radiation detected as negative luminescence are reviewed. The main properties of the devices based on this phenomenon are analyzed.

Advances in luminescence instrument systems

DEFF Research Database (Denmark)

Bøtter-Jensen, L.; Bulur, E.; Duller, G.A.T.

2000-01-01

We report on recent advances in the development of luminescence measurement systems and techniques at Riso. These include: (1) optical stimulation units based on new-generation powerful blue light (470 nm) emitting diodes providing up to 28 mW/cm(2) for OSL measurements; (2) an infrared (830 nm...

Dosimetry based on thermally and optically stimulated luminescence

International Nuclear Information System (INIS)

Agersnap Larsen, Niels

1999-01-01

Thermally Stimulated Luminescence (TL) and Optically Stimulated Luminescence (OSL) properties of quartz and α-Al 2 O 3 have been investigated. Anneling-induced OSL and TL sensitivity changes in quartz has been investigated by experiments and modelling. This study does not support a pre-dose effect to account for the observed annealing-induced sensitivity change. The experimental data indicates a more simple mechanism that involves alteration of the concentration of the defect centers. Results from modelling of removal or creation of defect centers comparing well with experimentally obtained data. Thermal quenching of luminescence for the main emission center, the F-center, in α-Al 2 O 3 :C has been investigated by analysing TL curves obtained at different heating rates. The thermal quenching dependence of luminescence is found to follow the classical Mott-Seitz expression. Basic investigations of OSL properties of αAl 2 O 3 :C, including: the thermal depth of the OSL traps, the temperature dependence of OSL, and the OSL stimulation spectra. Simultaneous measurements of TL and thermally stimulated conductivity (TSC) are presented for γ-irradiated αAl 2 O 3 :C. Activation energy analysis of the data reveals a superposition of several first-order TL and TSC peaks caused by release of charge carriers from a distribution of trapping states. Furthermore a description of an experimental method developed to determine the sign of the thermally released charge carriers has been presented. (au)

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.

Luminescent lanthanide reporters: new concepts for use in bioanalytical applications

International Nuclear Information System (INIS)

Vuojola, Johanna; Soukka, Tero

2014-01-01

Lanthanides represent the chemical elements from lanthanum to lutetium. They intrinsically exhibit some very exciting photophysical properties, which can be further enhanced by incorporating the lanthanide ion into organic or inorganic sensitizing structures. A very popular approach is to conjugate the lanthanide ion to an organic chromophore structure forming lanthanide chelates. Another approach, which has quickly gained interest, is to incorporate the lanthanide ions into nanoparticle structures, thus attaining improved specific activity and a large surface area for biomolecule immobilization. Lanthanide-based reporters, when properly shielded from the quenching effects of water, usually express strong luminescence emission, multiple narrow emission lines covering a wide wavelength range, and exceptionally long excited state lifetimes enabling time-gated luminescence detection. Because of these properties, lanthanide-based reporters have found widespread applications in various fields of life. This review focuses on the field of bioanalytical applications. Luminescent lanthanide reporters and assay formats utilizing these reporters pave the way for increasingly sensitive, simple, and easily automated bioanalytical applications. (topical review)

Non-Enzymatic-Browning-Reaction: A Versatile Route for Production of Nitrogen-Doped Carbon Dots with Tunable Multicolor Luminescent Display

Science.gov (United States)

Wei, Weili; Xu, Can; Wu, Li; Wang, Jiasi; Ren, Jinsong; Qu, Xiaogang

2014-01-01

The non-enzymatic browning, namely Maillard reaction is commonly invoked to account for abiotic chemical transformations of organic matter. Here we report a new reaction pathway via the Maillard reaction to systematically synthesize a series of nitrogen-doped carbon dots (C-dots) with superhigh quantum yield (QY) and tunable multicolor luminescent displayment. The starting materials are glucose and the serial amino acid analogues which allow systemically controlling luminescent and physicochemical properties of C-dots at will. Unexpectedly, the as-prepared C-dots possess bright photoluminescence with QY up to 69.1% which is almost the highest ever reported, favorable biocompatibility, excellent aqueous and nonaqueous dispersibility, ultrahigh photostability, and readily functionalization. We have demonstrated that they are particularly suitable for multicolor luminescent display and long-term and real-time cellular imaging. Furthermore, the methodology is readily scalable to large yield, and can provide sufficient amount of C-dots for practical demands.

Luminescent properties of (Y,Gd)BO3:Bi3+,RE3+ (RE=Eu, Tb) phosphor under VUV/UV excitation

International Nuclear Information System (INIS)

Zeng Xiaoqing; Im, Seoung-Jae; Jang, Sang-Hun; Kim, Young-Mo; Park, Hyoung-Bin; Son, Seung-Hyun; Hatanaka, Hidekazu; Kim, Gi-Young; Kim, Seul-Gi

2006-01-01

Bi 3+ - and RE 3+ -co-doped (Y,Gd)BO 3 phosphors were prepared and their luminescent properties under vacuum ultraviolet (VUV)/UV excitation were investigated. Strong red emission for (Y,Gd)BO 3 :Bi 3+ ,Eu 3+ and strong green emission for (Y,Gd)BO 3 :Bi 3+ ,Tb 3+ are observed under VUV excitation from 147 to 200 nm with a much broader excitation region than that of single Eu 3+ -doped or Tb 3+ -doped (Y,Gd)BO 3 phosphor. Strong emissions are also observed under UV excitation around 265 nm where as nearly no luminescence is observed for single Eu 3+ -doped or Tb 3+ -doped (Y,Gd)BO 3 . The luminescence enhancement of Bi 3+ - and RE 3+ -co-doped (Y,Gd)BO 3 phosphors is due to energy transfer from Bi 3+ ion to Eu 3+ or Tb 3+ ion not only in the VUV region but also in the UV region. Besides, host sensitization competition between Bi 3+ and Eu 3+ or Tb 3+ is also observed. The investigated phosphors may be preferable for devices with a VUV light 147-200 nm as an excitation source such as PDP or mercury-free fluorescent lamp

Identifying and selecting edible luminescent probes as sensors of food quality

Directory of Open Access Journals (Sweden)

Maria G. Corradini

2016-06-01

Full Text Available Foods contain a plethora of aromatic molecules—natural colors, synthetic dyes, flavors, vitamins, antioxidants, etc.—that are luminescent, exhibiting prompt fluorescence or delayed phosphorescence. Although food autofluorescence has been used to detect specific contaminants (e.g., aflatoxins or to authenticate specific foods (olive oil, much of the potential of using the optical luminescence of intrinsic molecules for sensing properties of foods is unrealized. We summarize here work characterizing the photophysical properties of some edible, and potentially GRAS (generally-recognized-as-safe, chromophores and especially their sensitivity to, and thus potential for sensing, various physical—viscosity, mobility/rigidity—or chemical—polarity, pH—properties of food known to reflect or be indicative of food quality, stability, and safety. A thorough-going characterization of and robust protocols for interpretation of the luminescent signals from edible chromophores can expand the repertoire of analytical techniques available to monitor quality, and even safety, of the food supply at various stages of production, distribution and storage or even at point of sale.

Luminescence properties of lustre decorated majolica

Science.gov (United States)

Galli, A.; Martini, M.; Sibilia, E.; Padeletti, G.; Fermo, P.

Luminescence measurements have been performed on several Italian Renaissance ceramic shards produced in central Italy, as well as on some others from Hispano-Moresque and Fatimid periods. The aim of this study was the characterisation of the raw materials used to manufacture lustre decorated majolica. At first, the thermoluminescence (TL) dating of all ceramic bodies was performed, because the shards lacked sure chronological attribution, having been provided by private collectors, or found during emergency restoration works or archaeological surveys. To characterise the defects and the recombination centers of the different components of the ceramics (ceramic body, glaze, glaze, and lustre), radioluminescence (RL) measurements have been performed on samples representative of each historical period. The dating results are reported, as well as the preliminary RL results.

Two luminescent frameworks constructed from lead(II) salts with carboxylate ligands containing dinuclear lead(II) units

International Nuclear Information System (INIS)

Zhu Xiandong; Li Xiaoju; Liu Qingyan; Lue Jian; Guo Zhengang; He Jinrun; Li Yafeng; Cao Rong

2007-01-01

Two luminescent Pb(II) coordination frameworks containing dinuclear lead(II) units, [Pb(PYDC)(H 2 O)] n (1) and [Pb(HPHT)] n (2) have been prepared by the self-assembly of lead(II) salts with pyridinecarboxylate and benzenecarboxylate. Single-crystal X-ray diffraction analyses reveal that compound 1 is a three-dimensional architecture consisting of Pb 2 O 2 dimeric building units, whereas compound 2 is a two-dimensional layer structure containing one-dimensional lead-oxide chains. The luminescent properties of 1 and 2 have been investigated in the solid state at room temperature, indicating structure-dependent photoluminescent properties of the coordination frameworks. - Graphical abstract: Two luminescent Pb(II) coordination frameworks, [Pb(PYDC)(H 2 O)] n (1) and [Pb(HPHT)] n (2) have been prepared. Single-crystal analyses reveal that compound 1 is a three-dimensional architecture consisting of Pb 2 O 2 dimeric building units, whereas compound 2 is a two-dimensional layer structure containing one-dimensional lead-oxide chains. The luminescent properties have been investigated, indicating structure-dependent photoluminescent properties of the coordination frameworks

Growth and luminescent properties of Li2B4O7 single crystal doped with Cu

International Nuclear Information System (INIS)

Bui The Huy; Bui Minh Ly; Vu Xuan Quang; Huynh Ky Hanh; Doan Phan Thao Tien; Vinh Hao; Tran Ngoc

2009-01-01

The authors have primarily succeeded in the study of the technology for growing single crystal Li 2 B 4 O 7 doped with Cu ions by Bridgman technique. The TL-3D spectra show peaks at around 375 nm (3d 9 4s → 3d 10 radiative excitation transition). This success opened up an opportunity in the radiotherapy to manufacture scintillators for neutron detection. The kinetic parameters of thermal stimulation luminescence were investigated by the three point method.

The morphology, microstructure, and luminescent properties of CdS/CdTe films

Energy Technology Data Exchange (ETDEWEB)

Al-Jassim, M.M.; Dhere, R.G.; Jones, K.M.; Hasoon, F.S.; Sheldon, P. [National Renewable Energy Lab., Golden, CO (United States)

1998-09-01

This paper is concerned with the characterization of CdS/CdTe polycrystalline thin films for solar cells. The morphology, microstructure, and luminescent properties are studied by a powerful array of characterization techniques. The presence of pinholes in 100-nm thick CdS is observed. The microstructure of CdS and CdTe films is shown to be heavily faulted polycrystalline. The effect of deposition temperature on the grain size and the microstructure is investigated. The interdiffusion of sulfur and tellurium at the CdS/CdTe interface is studied for the first time by a nanoprobe technique. Considerable amount of sulfur is detected in CdTe in the vicinity of the interface of samples deposited at 625 C. The recombination behavior of grain boundaries and intragrain defects is investigated in as-deposited and heat-treated samples.

Synthesis, Structure, and Luminescent Properties of Europium-Doped Hydroxyapatite Nanocrystalline Powders

Directory of Open Access Journals (Sweden)

Carmen Steluta Ciobanu

2012-01-01

Full Text Available The luminescent europium-doped hydroxyapatite (Eu:HAp, Ca10−xEux(PO46(OH2 with 0≤x≤0.2 nanocrystalline powders was synthesized by coprecipitation. The structural, morphological, and textural properties were well characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The vibrational studies were performed by Fourier transform infrared, Raman, and photoluminescence spectroscopies. The X-ray diffraction analysis revealed that hydroxyapatite is the unique crystalline constituent of all the samples, indicating that Eu has been successfully inserted into the HAp lattice. Eu doping inhibits HAp crystallization, leading to a decrease of the average crystallite size from around 20 nm in the undoped sample to around 7 nm in the sample with the highest Eu concentration. Furthermore, the samples show the characteristic 5D0→7F0 transition observed at 578 nm related to Eu3+ ions distributed on Ca2+ sites of the apatitic structure.

Synthesis, Structure, and Luminescent Properties of Europium-Doped Hydroxyapatite Nanocrystalline Powders

International Nuclear Information System (INIS)

Ciobanu, C.S.; Iconaru, S.L.; Predoi, D.; Massuyeau, F.; Constantin, L.V.; Costescu, A.

2012-01-01

The luminescent europium-doped hydroxyapatite (Eu:HAp, Ca 10-x Eu x (PO 4 ) 6 (OH) 2 ) with 0>x>0.2 nanocrystalline powders was synthesized by coprecipitation. The structural, morphological, and textural properties were well characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The vibrational studies were performed by Fourier transform infrared, Raman, and photoluminescence spectroscopies. The X-ray diffraction analysis revealed that hydroxyapatite is the unique crystalline constituent of all the samples, indicating that Eu has been successfully inserted into the HAp lattice. Eu doping inhibits HAp crystallization, leading to a decrease of the average crystallite size from around 20 nm in the undoped sample to around 7 nm in the sample with the highest Eu concentration. Furthermore, the samples show the characteristic 5 D 0 → 7 F 0 transition observed at 578 nm related to Eu 3+ ions distributed on Ca 2+ sites of the apatitic structure

Magnetic enhancement of photoluminescence from blue-luminescent graphene quantum dots

Science.gov (United States)

Chen, Qi; Shi, Chentian; Zhang, Chunfeng; Pu, Songyang; Wang, Rui; Wu, Xuewei; Wang, Xiaoyong; Xue, Fei; Pan, Dengyu; Xiao, Min

2016-02-01

Graphene quantum-dots (GQDs) have been predicted and demonstrated with fascinating optical and magnetic properties. However, the magnetic effect on the optical properties remains experimentally unexplored. Here, we conduct a magneto-photoluminescence study on the blue-luminescence GQDs at cryogenic temperatures with magnetic field up to 10 T. When the magnetic field is applied, a remarkable enhancement of photoluminescence emission has been observed together with an insignificant change in circular polarization. The results have been well explained by the scenario of magnetic-field-controlled singlet-triplet mixing in GQDs owing to the Zeeman splitting of triplet states, which is further verified by temperature-dependent experiments. This work uncovers the pivotal role of intersystem crossing in GQDs, which is instrumental for their potential applications such as light-emitting diodes, photodynamic therapy, and spintronic devices.

Synthesis and luminescence properties of KMgF{sub 3}:Tm{sup 3+} fluoro perovskite

Energy Technology Data Exchange (ETDEWEB)

Perez C, L.; Cruz Z, E. [UNAM, Instituto de Ciencias Nucleares, Circuito Exterior, Ciudad Universitaria, 04510 Mexico D. F. (Mexico); Marcazzo, J. [UNICEN, Instituto de Fisica Arroyo Seco, Gral. Pinto 399, B7000GHG Tandil (Argentina); Hernandez A, J. M.; Murrieta S, H., E-mail: ecruz@nucleares.unam.mx [UNAM, Instituto de Fisica, Circuito Exterior, Ciudad Universitaria, 04510 Mexico D. F. (Mexico)

2015-10-15

This paper presents the thermoluminescent (Tl) and radio luminescent (Rl) properties of the KMgF{sub 3} doped with Tm{sup 3+} ions at different concentration (0.05, 0.1, 0.2, 0.5 and 1.0 mol %). The KMgF{sub 3} binary compound was synthesized by solid state reaction. The characterization of the powder material was carried out by X-ray diffraction, scanning electron microscopy and by semiquantitative EDS analysis. The luminescence property of the powder and chips with Teflon samples was studied by thermoluminescence and radioluminescence phenomena. The Tl response as a function of the given dose was analyzed in the range between 0.5 Gy and 2500 Gy and a good linear response was obtained. Tl glow curves of KMgF{sub 3}:Tm show two overlapped peaks with maximums about 101, 146 degrees C and resolved peaks at 313 and 397 degrees C. The reproducibility of the Tl signal was tested and less than 5 % was obtained. The Tl signal decay was analyzed during a period of 33 days. Furthermore, the glow curve structure was studied by the thermal bleaching and the kinetics parameters values were obtained by a deconvolution process. On the other hand, the Rl response of different concentrations of thulium under beta irradiation was studied and the maximum of light output has been obtained for KMgF{sub 3} fluoro perovskite doped with 0.5 mol % of Tm{sup 3+} . The Rl spectrum showed the emission peaks at 455 and 360 nm, which can be ascribed to the {sup 1}D{sub 2}-{sup 3} F{sub 4} and {sup 1}D{sub 2}-{sup 3}H{sub 6} transitions of the Tm{sup 3+} ions. (Author)

Dose-dependent optically stimulated luminescence of synthetic quartz at room temperature

International Nuclear Information System (INIS)

Kale, Y.D.; Gandhi, Y.H.; Gartia, R.K.

2008-01-01

Physical conditions such as annealing temperature, duration of annealing, ionizing radiation, etc., play a significant role in the applications of optically stimulated luminescence (OSL) dating as well as OSL dosimetry. Many efforts are made to understand the effect of these physical parameters on quartz specimens owing to its use in such applications. Such factors induce changes in OSL decay pattern. The definite correlation between color centers and luminescence sensitivity can be established on account of such pre-treatments to the specimen. The purpose of present investigations is to study the effect of ionizing radiation under identical physical conditions on OSL properties measured at room temperature. The shapes of decay curve and dose-response data are considered for this purpose. This study can reveal the changes in color centers in response to the pre-conditions to the specimen. It was found that the OSL decay remains slow and OSL properties change systematically with the rise in beta dose up to a critical dose; however, it changes the pattern when the beta exposure to the specimen was increased higher than the critical dose. This critical dose was found to be different for different temperature of annealing. The shape of decay curve up to the critical dose was also studied by considering the difference of OSL intensities between two successive durations from the observed OSL decay data. The results are explained based on the changes in available shallow traps during OSL measurement at room temperature with changes in pre-conditions to the specimens. The results also have been confirmed with the corresponding changes in ESR signals

Luminescence of Ce doped oxygen crystalline compounds based on Hf and Ba

CERN Document Server

Borisevich, A E; Lecoq, P

2003-01-01

The luminescence properties of the Ce-doped hafnium and barium compounds have been investigated to determine their potential as heavy scintillation materials. Compounds have been prepared by solid state synthesis. All of them have shown a bright luminescence attributed to trivalent cerium. Emission bands are peaked in the 425-475nm spectral region at room temperature.

Preparation and photophysical properties of luminescent nanoparticles based on lanthanide doped fluorides (LaF3:Ce3+, Gd3+, Eu3+), obtained in the presence of different surfactants

International Nuclear Information System (INIS)

Runowski, Marcin; Lis, Stefan

2014-01-01

Highlights: • Synthesis of nanocrystalline lanthanide fluorides doped with Eu 3+ ions. • Inorganic nanomaterials exhibiting bright red luminescence. • Luminescence enhancement by energy transfer (ET) from Ce 3+ → Gd 3+ to Eu 3+ ions. • Decreased agglomeration and morphology control using organic modifiers/surfactants. • Absolute and relative quantum yield (QY) comparison. - Abstract: A series of nanomaterials composed of LaF 3 :Ce 3+ 10%, Gd 3+ 30%, Eu 3+ 1% was synthesized via a facile co-precipitation approach. The reaction between appropriate lanthanide (Ln 3+ ) and fluoride ions resulted in the formation of crystalline, Ln 3+ doped fluorides and was performed in the presence of a series of organic modifiers, acting as surfactants and anti-agglomeration agents. Modifiers such as polyacrylic acid (PAA), ethylenediaminetetraacetic acid (EDTA), citric acid and oleylamine most significantly influenced the morphology and spectroscopic properties of the products. The product obtained in the presence of PAA was composed of the smallest nanoparticles (ca. 5–6 nm), with narrow size/shape distribution. All fluorides synthesized exhibited intensive, bright red luminescence under UV irradiation (λ ex ≈ 250 nm), because of the presence of Eu 3+ ions in their structure. The efficient intensity of luminescence was a result of indirect excitation, via energy transfer (ET) phenomena occurring in the system (Ce 3+ → Gd 3+ → Eu 3+ ). The structure and morphology of the obtained nanomaterials were established by powder X-ray Diffraction (XRD) and Transmission Electron Microscopy (TEM) measurements. Optical properties of the obtained compounds were studied and discussed on the basis of excitation emission spectra and luminescence decay curves. On the basis of the performed measurements, luminescence quantum yield (absolute and relative) and radiative lifetimes were calculated and analyzed. FT-IR spectroscopy was applied to examine the presence of molecules of

Fingermark detection on non-porous and semi-porous surfaces using NaYF4:Er,Yb up-converter particles.

Science.gov (United States)

Ma, Rongliang; Bullock, Elicia; Maynard, Philip; Reedy, Brian; Shimmon, Ronald; Lennard, Chris; Roux, Claude; McDonagh, Andrew

2011-04-15

This article describes the first use of an anti-Stokes material, or up-converter, for the development of latent fingermarks on a range of non-porous surfaces. Anti-Stokes materials can absorb long-wavelength light and emit light at a shorter wavelength. This property is unusual in both natural and artificial materials and so fingermark detection techniques based on anti-Stokes luminescence are potentially sensitive and selective. Latent fingermarks on luminescent and non-luminescent substrates, including Australian polymer banknotes (a well-known 'difficult' surface), were developed with sodium yttrium tetrafluoride doped with erbium and ytterbium (NaYF(4):Er,Yb) by dry powder, wet powder, and cyanoacrylate staining techniques. This study illustrates the potential of up-converter phosphors for the detection of latent fingermarks. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Psychometric properties of Conversion Disorder Scale- Revised (CDS) for children.

Science.gov (United States)

Ijaz, Tazvin; Nasir, Attikah; Sarfraz, Naema; Ijaz, Shirmeen

2017-05-01

To revise conversion disorder scale and to establish the psychometric properties of the revised scale. This case-control study was conducted from February to June, 2014, at the Government College University, Lahore, Pakistan, and comprised schoolchildren and children with conversion disorder. In order to generate items for revised version of conversion disorder scale, seven practising mental health professionals were consulted. A list of 42 items was finalised for expert ratings. After empirical validation, a scale of 40 items was administered on the participants and factor analysis was conducted. Of the240 participants, 120(50%) were schoolchildren (controls group) and 120(50%)were children with conversion disorder (clinical group).The results of factor analysis revealed five factors (swallowing and speech symptoms, motor symptoms, sensory symptoms, weakness and fatigue, and mixed symptoms) and retention of all 40 items of revised version of conversion disorder scale. Concurrent validity of the revised scale was found to be 0.81 which was significantly high. Similarly, discriminant validity of the scale was also high as both clinical and control groups had significant difference (pconversion disorder scale was 76% sensitive to predicting conversion disorder while specificity showed that the scale was 73% accurate in specifying participants of the control group. The revised version of conversion disorder scale was a reliable and valid tool to be used for screening of children with conversion disorder.

Optically stimulated luminescence properties of Tm3+ doped KMgF3 fluoro perovskite

International Nuclear Information System (INIS)

Camargo, L.; Marcazzo, J.; Perez C, L.; Cruz Zaragoza, E.; Martinez O, S. A.

2017-10-01

In this work the optically stimulated luminescence (OSL) properties of undoped and Tm 3+ doped KMgF 3 fluoro perovskite have been investigated for the first time. OSL efficiency for stimulation with different wavelengths has been analyzed for each compound. The maximum OSL emission was found with blue light stimulation. The radioluminescence (Rl) spectra have shown two emission peaks at 455 and 360 nm, which can be ascribed to the 1 D 2 - 3 F 4 and 1 D 2 - 3 H 6 transitions of the Tm 3+ cations. It has been found that doping with Thulium 0.5 mol % renders the most intense OSL emission. Furthermore, several dosimetric properties such as OSL response as a function of dose, reproducibility of the OSL signal after several cycles of irradiation readout and the minimum detectable dose have been investigated. Finally, the OSL response of KMgF 3 : Tm 3+ has been compared to that of commercial Al 2 O 3 :C and the possible application of this fluoro perovskite to OSL dosimetry has been evaluated. (Author)

[Structure and luminescence properties of Ga2O3 : Cr3+ by Al doping].

Science.gov (United States)

Wang, Xian-Sheng; Wan, Min-Hua; Wang, Yin-Hai; Zhao, Hui; Hu, Zheng-Fa; Li, Hai-Ling

2013-11-01

The Al doping gallate phosphor (Ga(1-x)Al(x))2O3 : Cr3+ (x = 0, 0.1, 0.2, 0.3, 0.4, 0.5) was synthesized by a high temperature solid-state reaction method. The X-ray diffractions show that the phase of the phosphors remains to be Ga2 O3 structure with increase in the contents of Al3+ ion. Beside, the fact that the X-ray diffraction peak shifts towards big angles with increasing Al3+ ions content shows that Al3+ ions entered the Ga2 O3 lattice. The peaks of the excitation spectra located at 258, 300, 410 and 550 nm are attributed to the band to band transition of the matrix, charge transfer band transition, and 4A2 --> 4T1 and 4A2 --> 4T2 transition of Cr3+ ions, respectively. Those excitation spectrum peak positions show different degrees of blue shift with the increase in the Al3+ ions content. The blue shift of the first two peaks are due to the band gap energy of substrate and the electronegativity between Cr3+ ions and ligands increasing, respectively. The blue shift of the energy level transition of Cr3+ ion is attributed to crystal field strength increasing. The Cr3+ ion luminescence changes from a broadband emission to a narrow-band emission with Al3+ doping, because the emission of Cr3+ ion changed from 4 T2 --> 4A2 to 2E --> 4A2 transition with the crystal field change after Al3+ ions doping. The Al3+ ions doping improved the long afterglow luminescence properties of samples, and the sample showed a longer visible near infrared when Al3+ ions content reaches 0.5. The thermoluminescence curve shows the sample with suitable trap energy level, and this is also the cause of the long afterglow luminescence materials.

Persistent luminescence of Eu, Mn, Dy doped calcium phosphates for in-vivo optical imaging

Energy Technology Data Exchange (ETDEWEB)

Rosticher, Céline [UPMC Univ Paris 06, CNRS, UMR 7574, Chimie de la Matière Condensée de Paris, Collège de France, 11 place Marcelin Berthelot, 75231 Paris Cedex 05 (France); Viana, Bruno, E-mail: bruno.viana@chimie-paristech.fr [PSL Research University, Chimie ParisTech-CNRS, Institut de Recherche de Chimie Paris, 11 rue Pierre et Marie Curie, 75005 Paris (France); Maldiney, Thomas; Richard, Cyrille [Unité de Technologies Chimiques et Biologiques pour la Santé, CNRS, UMR 8258, Paris Cedex F-75270 (France); Inserm U1022, Paris Cedex F-75270 (France); Faculté des Sciences Pharmaceutiques et Biologiques, Université Paris Descartes, Sorbonne Paris Cité, Paris Cedex F-75270 (France); Chanéac, Corinne, E-mail: corinne.chaneac@upmc.fr [UPMC Univ Paris 06, CNRS, UMR 7574, Chimie de la Matière Condensée de Paris, Collège de France, 11 place Marcelin Berthelot, 75231 Paris Cedex 05 (France)

2016-02-15

Biocompatible nanoparticles possessing persistent luminescence properties offer attractive possibilities for in vivo imaging applications as it allows an excitation of the sensors outside the animal before injection and a long-lasting emission of light. Here we report the development of highly biocompatible calcium phosphate nanoparticles doped with europium, Mn{sup 2+} and Ln{sup 3+} (Ln{sup 3+}=Dy{sup 3+}, Pr{sup 3+}) ions synthesized by hydrothermal route and tailored to present red-near infrared persistent luminescence after UV excitation. Nanosize biphasic HAp/β-TCP compounds with sphere and rod-shaped were obtained. Two emission bands in the red-near infrared range were observed and attributed to {sup 4}T{sub 1}→{sup 6}A{sub 1} transitions of Mn{sup 2+} ions in HAp/β-TCP. An annealing treatment in reductive atmosphere post-synthesis was essential to reveal persistent luminescence properties. Indeed, such thermal treatment allows reducing Eu{sup 3+} ions in Eu{sup 2+} ions and generating required defaults as oxygen vacancies in the crystal necessary for red emission in accordance with persistent luminescence mechanism. These nanoparticles have been tested for the first time for in vivo imaging on small animal as proof of concept of prospective highly biocompatible nanoprobes. - Highlights: • Biocompatible HAp/b-TCP nanoparticles with persistent luminescence are investigated. • Reducing step induced persistent luminescence. • Nanoparticles have been tested for the first time for in vivo imaging. • Persistent luminescence is observed after 10 min in vivo.

Ion beam induced luminescence characterisation of CVD diamond films

Energy Technology Data Exchange (ETDEWEB)

Bettiol, A.A.; Gonon, P.; Jamieson, D.N. [Melbourne Univ., Parkville, VIC (Australia). School of Physics

1996-12-31

The characterisation of the band structure properties of materials and devices by ion microprobe techniques has been made possible at the Melbourne MeV ion microprobe facility with the development of Ion Beam Induced Luminescence (IBIL). A number of diamond films grown by Microwave Plasma Chemical Vapour Deposition (MPCVD) on silicon substrates are analysed. A preliminary study of the luminescence properties of these samples has revealed information not previously obtainable via traditional microprobe techniques. The optical effects of incorporating dopants during the deposition process is determined using IBIL. The presence of trace element impurities introduced during growth is examined by Particle Induced X-ray Emission (PIXE), and a measurement of the film thickness is made using Rutherford Backscattering Spectrometry (RBS). 7 refs., 2 figs.

Ion beam induced luminescence characterisation of CVD diamond films

Energy Technology Data Exchange (ETDEWEB)

Bettiol, A A; Gonon, P; Jamieson, D N [Melbourne Univ., Parkville, VIC (Australia). School of Physics

1997-12-31

The characterisation of the band structure properties of materials and devices by ion microprobe techniques has been made possible at the Melbourne MeV ion microprobe facility with the development of Ion Beam Induced Luminescence (IBIL). A number of diamond films grown by Microwave Plasma Chemical Vapour Deposition (MPCVD) on silicon substrates are analysed. A preliminary study of the luminescence properties of these samples has revealed information not previously obtainable via traditional microprobe techniques. The optical effects of incorporating dopants during the deposition process is determined using IBIL. The presence of trace element impurities introduced during growth is examined by Particle Induced X-ray Emission (PIXE), and a measurement of the film thickness is made using Rutherford Backscattering Spectrometry (RBS). 7 refs., 2 figs.

Dosimetry based on thermally and optically stimulated luminescence

Energy Technology Data Exchange (ETDEWEB)

Agersnap Larsen, Niels

1999-01-01

Thermally Stimulated Luminescence (TL) and Optically Stimulated Luminescence (OSL) properties of quartz and {alpha}-Al{sub 2}O{sub 3} have been investigated. Anneling-induced OSL and TL sensitivity changes in quartz has been investigated by experiments and modelling. This study does not support a pre-dose effect to account for the observed annealing-induced sensitivity change. The experimental data indicates a more simple mechanism that involves alteration of the concentration of the defect centers. Results from modelling of removal or creation of defect centers comparing well with experimentally obtained data. Thermal quenching of luminescence for the main emission center, the F-center, in {alpha}-Al{sub 2}O{sub 3}:C has been investigated by analysing TL curves obtained at different heating rates. The thermal quenching dependence of luminescence is found to follow the classical Mott-Seitz expression. Basic investigations of OSL properties of {alpha}Al{sub 2}O{sub 3}:C, including: the thermal depth of the OSL traps, the temperature dependence of OSL, and the OSL stimulation spectra. Simultaneous measurements of TL and thermally stimulated conductivity (TSC) are presented for {gamma}-irradiated {alpha}Al{sub 2}O{sub 3}:C. Activation energy analysis of the data reveals a superposition of several first-order TL and TSC peaks caused by release of charge carriers from a distribution of trapping states. Furthermore a description of an experimental method developed to determine the sign of the thermally released charge carriers has been presented. (au) 8 tabs., 59 ills., 90 refs.

Aspects of pre-dose and other luminescence phenomena in quartz absorbed dose estimation

International Nuclear Information System (INIS)

Adamiec, G.

2000-01-01

The understanding of all luminescence processes occurring in quartz is of paramount importance in the further development of robust absorbed dose estimation techniques (for the purpose of dating and retrospective dosimetry). The findings presented in this thesis, aid future improvements of absorbed dose estimation techniques using quartz by presenting investigations in the following areas: 1) interpretation of measurement results, 2) numerical modelling of luminescence in quartz, 3) phenomena needing inclusion in future physical models of luminescence. In the first part, the variability of properties of single quartz grains is examined. Through empirical and theoretical considerations, investigations are made of various problems of measurements of luminescence using multi-grain aliquots, and specifically areas where the heterogeneity of the sample at the inter-grain level may be misinterpreted at the multi-grain-aliquot level. The results obtained suggest that the heterogeneity of samples is often overlooked, and that such differences can have a profound influence on the interpretation of measurement results. Discussed are the shape of TL glow curves, OSL decay curves, dose response curves (including consequences for using certain signals as proxies for others), normalisation procedures and D E estimation techniques. Further, a numerical model of luminescence is proposed, which includes multiple R-centres and is used to describe the pre-dose sensitisation in quartz. The numerical model exhibits a broad-scale behaviour observed experimentally in a sample of annealed quartz. The shapes of TAC for lower (20 Gy) and higher doses (1 kGy) and the evolution with temperature of the isothermal sensitisation curves are qualitatively matched for the empirical and numerical systems. In the third area, a preliminary investigation of the properties of the '110 deg. C peak' in the 550 nm emission band, in annealed quartz is presented. These properties are in sharp contrast with

X-Ray Absorption Near-Edge Structure (XANES) of Calcium L3,2 Edges of Various Calcium Compounds and X-Ray Excited Optical Luminescence (XEOL) Studies of Luminescent Calcium Compounds

International Nuclear Information System (INIS)

Ko, J. Y. Peter; Zhou Xingtai; Sham, T.-K.; Heigl, Franziskus; Regier, Tom; Blyth, Robert

2007-01-01

X-ray absorption at calcium L3,2 edges of various calcium compounds were measured using a high resolution Spherical Grating Monochromator (SGM) at the Canadian Light Source (CLS). We observe that each compound has its unique fine structure of L3,2 edges. This uniqueness is due to differences in local structure of compounds. We also performed (X-ray Excited Optical Luminescence) XEOL of selected luminescent calcium compounds to investigate their optical properties. XEOL is a photon-in-photon-out technique in which the optical luminescence that is excited by tunable x-rays from a synchrotron light source is monitored. Depending on excitation energy of the x-ray, relative intensities of luminescence peaks vary. Recent findings of the results will be presented here

Phase transformation, morphology evolution and luminescence property variation in Y{sub 2}O{sub 3}: Eu hollow microspheres

Energy Technology Data Exchange (ETDEWEB)

Wang, Qin; Guo, Jing; Jia, Wenjing; Liu, Baocang [College of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot (China); Zhang, Jun, E-mail: cejzhang@sina.com [College of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot (China)

2012-11-25

Highlights: Black-Right-Pointing-Pointer We report a general and facile method for the synthesis of Y{sub 2}O{sub 3}: Eu hollow microspheres. Black-Right-Pointing-Pointer This method may be of great significance in the synthesis of many other hollow spherical materials. Black-Right-Pointing-Pointer Phase, morphology and luminescence property were found to be strongly dependent on temperature and pH. Black-Right-Pointing-Pointer The evolution process under various temperatures and pH values were discussed. Black-Right-Pointing-Pointer The sample shows a strong red emission under short UV irradiation, and the lifetime is determined to be 7.0 ms. - Abstract: Y{sub 2}O{sub 3}: Eu hollow microspheres with average size of 500-600 nm have been successfully synthesized via a solvothermal method in the presence of sodium citrate as surfactant followed by a subsequent heat treatment process. High polymer F127(EO{sub 106}PO{sub 70}EO{sub 106}) served as a soft template in the formation of as prepared hollow microspheres. It is found that the pH values and the reaction temperature are two crucial factors in determining the phase, morphology and luminescence properties of the Y{sub 2}O{sub 3}: Eu hollow microspheres. Morphology evolution can be achieved by changing the pH and the reaction temperature. The properties of the Eu{sup 3+}-doped Y{sub 2}O{sub 3}: Eu nanocrystals were characterized by XRD, FE-SEM, HR-TEM and UV-vis spectroscopy.

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

Luminescent Lanthanide Metal Organic Frameworks for cis-Selective Isoprene Polymerization Catalysis

Directory of Open Access Journals (Sweden)

Samantha Russell

2015-11-01

Full Text Available In this study, we are combining two areas of chemistry; solid-state coordination polymers (or Metal-Organic Framework—MOF and polymerization catalysis. MOF compounds combining two sets of different lanthanide elements (Nd3+, Eu3+/Tb3+ were used for that purpose: the use of neodymium was required due to its well-known catalytic properties in dienes polymerization. A second lanthanide, europium or terbium, was included in the MOF structure with the aim to provide luminescent properties. Several lanthanides-based MOF meeting these criteria were prepared according to different approaches, and they were further used as catalysts for the polymerization of isoprene. Stereoregular cis-polyisoprene was received, which in some cases exhibited luminescent properties in the UV-visible range.

Study of the absorption and energy transfer processes in inorganic luminescent materials in the UV and VUV region; Etude des processus d`absorption et de transfert d`energie au sein de materiaux inorganiques luminescents dans le domaine UV et VUV

Energy Technology Data Exchange (ETDEWEB)

Mayolet, A

1995-11-29

In order to find a green emitting phosphor showing high quantum efficiency and a short decay time which can be used in the color Plasma Display Panels developed by Thomson-TTE-TIV company, a VUV spectrophotometer built at IPN Orsay, using the synchrotron radiation from the SUPER-ACO storage ring as an excitation source, allow us the simultaneous recording of the luminescence excitation and diffuse reflectivity spectra of the inorganic compounds in the UV-VUV range. In addition, this experimental set-up enable us to determine the luminescence quantum efficiency of phosphors in the whole energy range of investigation. The chemical synthesis of rare-earth ortho-- and metaborate and rare-earth ortho- and metaphosphate doped with trivalent lanthanide ions cerium, praseodymium, europium and terbium have been made. The energy variation of the thresholds of the luminescence excitation mechanisms in function of the nature and the structure of the host matrix is discussed. We have determined the influence of the nephelauxetic effect and the crystal field intensity on the energy of the f-d inter-configuration transitions. The variation of the luminescence quantum efficiency of the dopant ion is interpreted through the `impurity bound exciton` model. The systematic comparison of the cerium and terbium trivalent ions spectroscopic properties in the Y(AG)G host lattice series stands to reason that the self-ionized state of the luminescent center plays an important role in the rate of the non radiative relaxation. It is the redox power of the host matrix which imposes to the luminescent center, the energy of this state. (author) 134 refs.

Cone Beam X-Ray Luminescence Tomography Imaging Based on KA-FEM Method for Small Animals.

Science.gov (United States)

Chen, Dongmei; Meng, Fanzhen; Zhao, Fengjun; Xu, Cao

2016-01-01

Cone beam X-ray luminescence tomography can realize fast X-ray luminescence tomography imaging with relatively low scanning time compared with narrow beam X-ray luminescence tomography. However, cone beam X-ray luminescence tomography suffers from an ill-posed reconstruction problem. First, the feasibility of experiments with different penetration and multispectra in small animal has been tested using nanophosphor material. Then, the hybrid reconstruction algorithm with KA-FEM method has been applied in cone beam X-ray luminescence tomography for small animals to overcome the ill-posed reconstruction problem, whose advantage and property have been demonstrated in fluorescence tomography imaging. The in vivo mouse experiment proved the feasibility of the proposed method.

Effect of biomass feedstock chemical and physical properties on energy conversion processes: Volume 1, Overview

Energy Technology Data Exchange (ETDEWEB)

Butner, R.S.; Elliott, D.C.; Sealock, L.J. Jr.; Pyne, J.W.

1988-12-01

Pacific Northwest Laboratory has completed an initial investigation of the effects of physical and chemical properties of biomass feedstocks relative to their performance in biomass energy conversion systems. Both biochemical conversion routes (anaerobic digestion and ethanol fermentation) and thermochemical routes (combustion, pyrolysis, and gasification) were included in the study. Related processes including chemical and physical pretreatment to improve digestibility, and size and density modification processes such as milling and pelletizing were also examined. This overview report provides background and discussion of feedstock and conversion relationships, along with recommendations for future research. The recommendations include (1) coordinate production and conversion research programs; (2) quantify the relationship between feedstock properties and conversion priorities; (3) develop a common framework for evaluating and characterizing biomass feedstocks; (4) include conversion effects as part of the criteria for selecting feedstock breeding programs; and (5) continue emphasis on multiple feedstock/conversion options for biomass energy systems. 9 refs., 3 figs., 2 tabs.

Luminescence of nanocrystalline ZnSe:Mn2+

NARCIS (Netherlands)

Suyver, J.F.; Wuister, S.F.; Kelly, J.J.; Meijerink, A.

2000-01-01

The luminescence properties of nanocrystalline ZnSe:Mn^(2+) prepared via an inorganic chemical synthesis are described. Photoluminescence spectra show distinct ZnSe and Mn^(2+) related emissions, both of which are excited via the ZnSe host lattice. The Mn^(2+) emission wavelength and the

Luminescence and scintillation properties of YAG:Ce single crystal and optical ceramics

CERN Document Server

Mihóková, E; Mareš, J A; Beitlerová, A; Vedda, A; Nejezchleb, K; Blažek, K; D’Ambrosio, C

2007-01-01

We use various techniques to study optical and scintillation properties of Ce-doped yttrium aluminum garnet, Y3Al5O12 (YAG:Ce), in the form of a high-quality industrial single crystal. This was compared to optical ceramics prepared from YAG:Ce nanopowders. We present experimental data in the areas of optical absorption, radioluminescence, scintillation decay, photoelectron yield, thermally stimulated luminescence and radiation-induced absorption. The results point to an interesting feature—the absence of antisite (YAl, i.e. Y at the Al site) defects in optical ceramics. The scintillation decay of the ceramics is faster than that of the single crystal, but its photoelectron yield (measured with 1 μs integration time) is about 30–40% lower. Apart from the photoelectron yield value the YAG:Ce optical ceramic is fully comparable to a high quality industrial YAG:Ce single crystal and can become a competitive scintillator material.

Luminescence studies on phosphor screens

International Nuclear Information System (INIS)

Panayiotakis, G.; Nomikos, C.; Bakas, A.; Proimos, B.

1994-01-01

We report our results on x-ray phosphor screens prepared of some new materials focusing attention on their efficiency under fluoroscopy conditions, on optimization conditions and on comparisons among the various materials. All data are presented in absolute values. A theoretical model is presented, that takes into account the granular structure of the screens, permitting the explanation and prediction of the luminescence properties of the screens. (authors)

Luminescent Properties of Sr4Si3O8Cl4:Eu2+, Bi3+ Phosphors for Near UV InGaN-Based Light-Emitting-Diodes

Directory of Open Access Journals (Sweden)

Wangqing Shen

2015-12-01

Full Text Available Sr4Si3O8Cl4 co-doped with Eu2+, Bi3+ were prepared by the high temperature reaction. The structure and luminescent properties of Sr4Si3O8Cl4:Eu2+, Bi3+ were investigated. With the introduction of Bi3+, luminescent properties of these phosphors have been optimized. Compared with Sr3.90Si3O8Cl4:0.10Eu2+, the blue-green phosphor Sr3.50Si3O8Cl4:0.10Eu2+, 0.40Bi3+ shows stronger blue-green emission with broader excitation in near-UV range. Bright blue-green light from the LED means this phosphor can be observed by the naked eye. Hence, it may have an application in near UV LED chips.

Synthesis and luminescence properties of novel Sr{sub 3}Gd(PO{sub 4}){sub 3}:Dy{sup 3+} phosphor

Energy Technology Data Exchange (ETDEWEB)

Xu, Qiguang; Sun, Jiayue, E-mail: Jiayue_sun@126.com; Cui, Dianpeng; Di, Qiumei; Zeng, Junhui

2015-02-15

Sr{sub 3}(Gd{sub 1−x}Dy{sub x})(PO{sub 4}){sub 3} phosphors for white light-emitting diodes (w-LEDs) were prepared by the conventional solid-state reaction. X-ray diffraction (XRD) and photoluminescence spectra were utilized to characterize the structure and luminescence properties of the as-synthesized phosphors. Luminescence properties shows that the phosphor can be efficiently excited by the ultraviolet visible light in the region from 300 to 450 nm, and it exhibits blue (483 nm) and yellow (575 nm) emission corresponding to {sup 4}F{sub 9/2}→{sup 6}H{sub 15/2} transition and {sup 4}F{sub 9/2}→{sup 6}H{sub 13/2} transition, respectively. It has been found that concentration quenching occurs via dipole–dipole interaction according to Dexter's theory. The temperature dependence of photoluminescence properties is investigated from 25 to 250 °C and the prepared Sr{sub 3}Gd(PO{sub 4}){sub 3}:Dy{sup 3+} phosphors show good thermal quenching properties. - Highlights: • Sr{sub 3}Gd(PO{sub 4}){sub 3}:Dy{sup 3+} phosphors were synthesized by a solid-state reaction method. • The phosphor could be efficiently excited by the UV–vis light region from 300 to 450 nm. • Sr{sub 3}Gd(PO{sub 4}){sub 3}:Dy{sup 3+} phosphors exhibited blue (483 nm) and yellow (575 nm) emission. • The Sr{sub 3}Gd(PO{sub 4}){sub 3}:Dy{sup 3+} phosphors concentration quenching occurred as a result of dipole–dipole interaction. • Sr{sub 3}Gd(PO{sub 4}){sub 3}:Dy{sup 3+} phosphors showed good thermal quenching properties.

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.

Terahertz-wave differential detection based on simultaneous dual-wavelength up-conversion

Directory of Open Access Journals (Sweden)

Yuma Takida

2017-03-01

Full Text Available We report a terahertz (THz-wave differential detection based on simultaneous dual-wavelength up-conversion in a nonlinear optical MgO:LiNbO3 crystal with optical and electronic THz-wave sources. The broadband parametric gain and noncollinear phase-matching of MgO:LiNbO3 provide efficient conversion from superposed THz waves to spatially distributed near-infrared (NIR beams to function as a dispersive THz-wave spectrometer without any additional dispersive element. We show that the μW-level THz waves from two independent sources, a 0.78-THz injection-seeded THz-wave parametric generator (is-TPG and a 1.14-THz resonant tunneling diode (RTD, are simultaneously up-converted to two NIR waves and then detected with two NIR photodetectors. By applying a balanced detection scheme to this dual-frequency detection, we demonstrate THz-wave differential imaging of maltose and polyethylene pellets in the transmission geometry. This dual-wavelength detection is applicable to more than three frequencies and broadband THz-wave radiation for real-time THz-wave spectroscopic detection and imaging.

The role of phosphate conversion coatings in make-up of casing connections

NARCIS (Netherlands)

Ernens, D; van Riet, E.J.; de Rooij, M.B.; Pasaribu, H.R.; van Haaften, W.M.; Schipper, D.J.

2017-01-01

Phosphate conversion coatings are widely used on (premium) casing connections for protection against corrosion. Next to that, in conjunction with the lubricant these coatings provide galling protection. The friction and wear that occurs during make-up and subsequent load cycling determines the

Sensitive luminescent determination of DNA using the terbium(III)-difloxacin complex

International Nuclear Information System (INIS)

Yegorova, Alla V.; Scripinets, Yulia V.; Duerkop, Axel; Karasyov, Alexander A.; Antonovich, Valery P.; Wolfbeis, Otto S.

2007-01-01

The interaction of the terbium-difloxacin complex (Tb-DFX) with DNA has been examined by using UV-vis absorption and luminescence spectroscopy. The Tb-DFX complex shows an up to 85-fold enhancement of luminescence intensity upon titration with DNA. The long decay times allow additional detection schemes like time-resolved measurements in microplate readers to enhance sensitivity by off-gating short-lived background luminescence. Optimal conditions are found at equimolar concentrations of Tb 3+ and DFX (0.1 or 1 μM) at pH 7.4. Under these conditions, the luminescence intensity is linearly dependent on the concentration of ds-DNAs and ss-DNA between 1-1500 ng mL -1 and 4.5-270 ng mL -1 , respectively. The detection limit is 0.5 ng mL -1 for ds-DNAs and 2 ng mL -1 for ss-DNA. The mechanism for the luminescence enhancement was also studied

Study of the absorption and energy transfer processes in inorganic luminescent materials in the UV and VUV region

International Nuclear Information System (INIS)

Mayolet, A.

1995-01-01

In order to find a green emitting phosphor showing high quantum efficiency and a short decay time which can be used in the color Plasma Display Panels developed by Thomson-TTE-TIV company, a VUV spectrophotometer built at IPN Orsay, using the synchrotron radiation from the SUPER-ACO storage ring as an excitation source, allow us the simultaneous recording of the luminescence excitation and diffuse reflectivity spectra of the inorganic compounds in the UV-VUV range. In addition, this experimental set-up enable us to determine the luminescence quantum efficiency of phosphors in the whole energy range of investigation. The chemical synthesis of rare-earth ortho-- and metaborate and rare-earth ortho- and metaphosphate doped with trivalent lanthanide ions cerium, praseodymium, europium and terbium have been made. The energy variation of the thresholds of the luminescence excitation mechanisms in function of the nature and the structure of the host matrix is discussed. We have determined the influence of the nephelauxetic effect and the crystal field intensity on the energy of the f-d inter-configuration transitions. The variation of the luminescence quantum efficiency of the dopant ion is interpreted through the 'impurity bound exciton' model. The systematic comparison of the cerium and terbium trivalent ions spectroscopic properties in the Y(AG)G host lattice series stands to reason that the self-ionized state of the luminescent center plays an important role in the rate of the non radiative relaxation. It is the redox power of the host matrix which imposes to the luminescent center, the energy of this state. (author)

Luminescent, Fire-Resistant, and Water-Proof Ultralong Hydroxyapatite Nanowire-Based Paper for Multimode Anticounterfeiting Applications.

Science.gov (United States)

Yang, Ri-Long; Zhu, Ying-Jie; Chen, Fei-Fei; Dong, Li-Ying; Xiong, Zhi-Chao

2017-08-02

Counterfeiting of valuable certificates, documents, and banknotes is a serious issue worldwide. As a result, the need for developing novel anticounterfeiting materials is greatly increasing. Herein, we report a new kind of ultralong hydroxyapatite nanowire (HAPNW)-based paper with luminescence, fire resistance, and waterproofness properties that may be exploited for anticounterfeiting applications. In this work, lanthanide-ion-doped HAPNWs (HAPNW:Ln 3+ ) with lengths over 100 μm have been synthesized and used as a raw material to fabricating a free-standing luminescent, fire-resistant, water-proof paper through a simple vacuum filtration process. It is interesting to find that the luminescence intensity, structure, and morphology of HAPNW:Ln 3+ highly depend on the experimental conditions. The as-prepared HAPNW:Ln 3+ paper has a unique combination of properties, such as high flexibility, good processability, writing and printing abilities, luminescence, tunable emission color, waterproofness, and fire resistance. In addition, a well-designed pattern can be embedded in the paper that is invisible under ambient light but viewable as a luminescent color under ultraviolet light. Moreover, the HAPNW:Ln 3+ paper can be well-preserved without any damage after being burned by fire or soaked in water. The unique combination of luminescence, fire resistance, and waterproofness properties and the nanowire structure of the as-prepared HAPNW:Ln 3+ paper may be exploited toward developing a new kind of multimode anticounterfeiting technology for various high-level security antiforgery applications, such as in making forgery-proof documents, certificates, labels, and tags and in packaging.

Scintillation and optical stimulated luminescence of Ce-doped CaF2

International Nuclear Information System (INIS)

Yanagida, Takayuki; Fujimoto, Yutaka; Watanabe, Kenichi; Fukuda, Kentaro; Kawaguchi, Noriaki; Miyamoto, Yuka; Nanto, Hidehito

2014-01-01

Scintillation and optical stimulated luminescence of Ce 0.1–20% doped CaF 2 crystals prepared by Tokuyama Corp. were investigated. In X-ray induced scintillation spectra, luminescence due to Ce 3+ 5d–4f transition appeared around 320 nm with typically 40 ns decay time. By 241 Am 5.5 MeV α-ray irradiation, 0.1% doped one showed the highest scintillation light yield and the light yield monotonically decreased with Ce concentrations. Optically stimulated luminescence after X-ray irradiation was observed around 320 nm under 550 or 830 nm stimulation in all samples. As a result, intensities of optically stimulated luminescence were proportional to Ce concentrations. Consequently, scintillation and optically stimulated luminescence resulted to have a complementary relation in Ce-doped CaF 2 system. - Highlights: • Optical, scintillation, and OSL properties of Ce 0.1–20% doped CaF 2 were studied. • Scintillation light yield exhibited inverse proportionality to Ce concentrations. • OSL intensities showed proportionality to Ce concentrations. • Complementary relation of scintillation and OSL was experimentally confirmed

Application of pulse spectro- zonal luminescent method for the rapid method of material analysis

International Nuclear Information System (INIS)

Lisitsin, V.M.; Oleshko, V.I.; Yakovlev, A.N.

2004-01-01

Full text: The scope of luminescent methods of the analysis covers enough a big around of substances as the luminescence can be excited in overwhelming majority of nonmetals. Analytical opportunities of luminescent methods can be essentially expanded by use of pulse excitation and registration of spectra of a luminescence with the time resolved methods. The most perspective method is to use pulses of high-current electron beams with the nanosecond duration for excitation from the following reasons: excitation is carried out ionizing, deeply enough by a penetrating radiation; the pulse of radiation has high capacity, up to 10 8 W, but energy no more than 1 J; the pulse of radiation has the nanosecond duration. Electrons with energy in 300-400 keV will penetrate on depth into some tenth shares of mm, i.e. they create volumetric excitation of a sample. Therefore the luminescence raised by an electronic beam has the information about volumetric properties of substance. High density of excitation allow to find out and study the centers (defects) having a small yield of a luminescence, to analyze the weakly luminescent objects. Occurrence of the new effects is possible useful to analyze of materials. There is an opportunity of reception of the information from change of spectral structure of a luminescence during the time after the ending of a pulse of excitation and kinetic characteristics of attenuation of luminescence. The matter is the energy of radiation is absorbed mainly by a matrix, then electronic excitations one is transferred the centers of a luminescence (defects) of a lattice. Therefore during the time after creation electronic excitations the spectrum of a luminescence can repeatedly change, transferring the information on the centers (defects) which are the most effective radiators at present time. Hence, the study of change of spectra of radiation during the time allows providing an additional way of discrimination of the information on the centers of a

Silica- and silylated europium-based luminescent hybrids: new analysis tools for biological environments

International Nuclear Information System (INIS)

Pereira Duarte, Adriana

2012-01-01

The association of the very interesting luminescence properties of the lanthanide chelates with the physicochemical properties of inorganic matrix such as silica is a promising way to obtain new probes or luminescent markers for biology analyses. In this idea, this work focuses on the preparation of new hybrid materials based on the grafting of new europium(III) complexes on silica nanoparticles. These europium complexes were developed in our group using bifunctional ligands containing both complexing and grafting sites. Intrinsic characteristic of the ligands gives us the ability to make a covalent bond between the material surface and the complex. Two different methodologies were used; the first one is the direct grafting reaction involving the complex and silica nanoparticles (i.e. dense or meso-porous particles). The second one is the Stoeber reaction, where the SiO 2 nanoparticles were prepared in presence of the europium complex. The last methodology has an additional difficult, because of the presence of silylated europium complex, it needs a closer control of the physicochemical conditions. The new organic-inorganic hybrid materials, obtained in this work, present an interesting luminescence behavior and this one is depending on the localization of the europium complex, i.e. on the surface or within the nanoparticles. In addition, the obtained hybrids present the nano-metric dimension and the complex is not leachable. Analyses were realized to describe the luminescence properties, beyond surface and structural characteristics. Initial results show that the new hybrids are promising candidates for luminescent bio-markers, particularly for the time-resolved analysis. (author) [fr

Time-resolved luminescence from quartz: An overview of contemporary developments and applications

Energy Technology Data Exchange (ETDEWEB)

Chithambo, M.L., E-mail: m.chithambo@ru.ac.za [Department of Physics and Electronics, Rhodes University, PO BOX 94, Grahamstown 6140 (South Africa); Ankjærgaard, C. [Soil Geography and Landscape Group, Wageningen University Netherlands Centre for Luminescence Dating, Droevendaalsesteeg 3, 6708 PB Wageningen, The Netherlands (Netherlands); Pagonis, V. [McDaniel College, Physics Department, Westminster, MD 21157 (United States)

2016-01-15

Time-resolved optical stimulation of luminescence has become established as a key method for measurement of optically stimulated luminescence from quartz, feldspar and α-Al{sub 2}O{sub 3}:C, all materials of interest in dosimetry. The aim of time-resolved optical stimulation is to separate in time the stimulation and emission of luminescence. The luminescence is stimulated from a sample using a brief light pulse and the emission monitored during stimulation in the presence of scattered stimulating light or after pulsing, over photomultiplier noise only. Although the use of the method in retrospective dosimetry has been somewhat limited, the technique has been successfully applied to study mechanisms in the processes leading up to luminescence emission. The main means for this has been the temperature dependence of the luminescence intensity as well as the luminescence lifetimes determined from time-resolved luminescence spectra. In this paper we review some key developments in theory and applications to quartz including methods of evaluating lifetimes, techniques of evaluating kinetic parameters using both the dependence of luminescence intensity and lifetime on measurement temperature, and of lifetimes on annealing temperature. We then provide an overview of some notable applications such as separation of quartz signals from a quartz–feldspar admixture and the utility of the dynamic throughput, a measure of luminescence measured as a function of the pulse width. The paper concludes with some suggestions of areas where further exploration would advance understanding of dynamics of luminescence in quartz and help address some outstanding problems in its application.

STUDIES ON BIOLUMINESCENCE : XVII. FLUORESCENCE AND INHIBITION OF LUMINESCENCE IN CTENOPHORES BY ULTRA-VIOLET LIGHT.

Science.gov (United States)

Harvey, E N

1925-01-20

1. Small dumps of the luminous cells of Mnemiopsis cannot readily be stimulated mechanically but will luminesce on treatment with saponin solution. Larger groups of luminous cells (such as are connected with two paddle plates) luminesce on mechanical stimulation. This suggests that mechanical stimulation to luminesce occurs chiefly through a nerve mechanism which has been broken up in the small dumps of luminous tissue. 2. The smallest bits of luminous tissue, even cells freed from the animal by agitation, that will pass through filter paper, lose their power to luminesce in daylight and regain it (at least partially) in the dark. 3. Luminescence of the whole animal and of individual cells is suppressed by near ultra-violet light (without visible light). 4. Inhibition in ultra-violet light is not due to stimulation (by the ultra-violet light) of the animal to luminesce, thereby using up the store of photogenic material. 5. Animals stimulated mechanically several times and placed in ultra-violet light show a luminescence along the meridians in the same positions as the luminescence that appears on stimulation. This luminescence in the ultra-violet or "tonic luminescence," is not obtained with light adapted ctenophores and is interpreted to be a fluorescence of the product of oxidation of the photogenic material. 6. Marked fluorescence of the luminous organ of the glowworm (Photuris) and of the luminous slime of Chatopterus may be observed in ultra-violet but no marked fluorescence of the luminous substances of Cypridina is apparent. 7. Evidence is accumulating to show a close relation between fluorescent and chemiluminescent substances in animals, similar to that described for unsaturated silicon compounds and the Grignard reagents.

Synthesis, crystal structures and luminescence properties of two metal carboxyphosphonates

Energy Technology Data Exchange (ETDEWEB)

Wang, Chaonan; Feng, Pingjing; Li, Jintang, E-mail: leejt@xmu.edu.cn; Luo, Xuetao

2017-05-15

Two metal carboxyphosphonates, [Co{sub 2}(OOCC{sub 5}H{sub 3}NPO{sub 3}){sub 2·}(H{sub 2}O){sub 3}] (Compound1) and Zn{sub 3}[OOCC{sub 6}H{sub 3}CH(OH)PO{sub 3}]{sub 2·}2H{sub 2}O (Compound2) were successfully synthesized under the hydrothermal reactions. In compound 1, two (Co1-NO{sub 5}) octahedra link the (CPO{sub 3}) by sharing the corner, which link the two (Co2-O{sub 6}) octahedra. From a-axis the six clusters form the layer. Each layer is linked through hydrogen bond. In compound 2, the (Zn-O{sub 4}) tetrahedron and (CPO{sub 3}) tetrahedron are corner-shared, which arrange in line. From a-axis, each line forms the columnar. The thermal and luminescence properties of these compounds were investigated. - Graphical abstract: The synthesis conditions of the two compounds and the crystal morphology. Compound 1 shows the layer and the compound 2 shows the pillared-layer. - Highlights: • Two new carboxyphosphonate ligands have been prepared. • Using the two ligands, two metal carboxyphosphonates have been synthesized. • The two MOFs may be candidates for fluorescent materials.

Multi-channel up-conversion infrared spectrometer and method of detecting a spectral distribution of light

DEFF Research Database (Denmark)

2015-01-01

A multi-channel infrared spectrometer for detecting an infrared spectrum of light received from an object. The spectrometer comprises a wavelength converter system comprising a nonlinear material and having an input side and an output side. The wavelength converter system comprises at least a first...... on the first side into light in a second output wavelength range output on the second side. The spectrometer further comprises a demultiplexer configured for demultiplexing light in the first up-conversion channel and light in the second up-conversion channel. The demultiplexer is located on the first side...

Structure, electronic properties, luminescence and chromaticity investigations of rare earth doped KMgBO{sub 3} phosphors

Energy Technology Data Exchange (ETDEWEB)

Zheng, Jianghui; Cheng, Qijin [School of Energy Research, Xiamen University, Xiamen 361005 (China); Wu, Shunqing [Department of Physics, Xiamen University, Xiamen, 361005 (China); Zhuang, Yixi [College of Materials, Xiamen University, Xiamen 361005 (China); Guo, Ziquan; Lu, Yijun [Department of Electronic Science, Fujian Engineering Research Center for Solid-state Lighting, Xiamen University, Xiamen 361005 (China); Chen, Chao, E-mail: cchen@xmu.edu.cn [School of Energy Research, Xiamen University, Xiamen 361005 (China); Department of Physics, Xiamen University, Xiamen, 361005 (China); Department of Electronic Science, Fujian Engineering Research Center for Solid-state Lighting, Xiamen University, Xiamen 361005 (China)

2015-09-01

In this work, the optimization of the geometry and the electronic properties of the host matrix KMgBO{sub 3} were investigated using density functional theory, and the comprehensive photoluminescence and chromaticity properties on five rare earth ion-doped (RE = Ce{sup 3+}, Tm{sup 3+}, Tb{sup 3+}, Eu{sup 3+}, Dy{sup 3+}) KMgBO{sub 3} phosphors were also studied. By introducing RE ions into the KMgBO{sub 3} host, excellent purple, blue, green, red and white emitting light could be obtained under the near-ultraviolet light excitation. The results suggest that rare earth doped KMgBO{sub 3} phosphors are potential luminescence materials for the application in the near-ultraviolet white light-emitting diodes. - Highlights: • The electronic properties of the host matrix KMgBO{sub 3} were investigated. • The PL properties on rare earth ions doped KMgBO{sub 3} phosphors were studied. • The chromaticity properties on rare earth ions doped KMgBO{sub 3} samples were studied. • Tm{sup 3+} and Eu{sup 3+} doped KMgBO{sub 3} samples show higher color purity than commercial phosphors.

Metal-enhanced luminescence: Current trend and future perspectives- A review

International Nuclear Information System (INIS)

Ranjan, Rajeev; Esimbekova, Elena N.; Kirillova, Maria A.; Kratasyuk, Valentina A.

2017-01-01

Optically enhanced biosensing strategies are prerequisites for developing miniature and highly sensitive multiplexed analytical platforms. Such smart biosensing systems are highly promising for use in the fields of biomedicine and environmental monitoring. Optical signal enhancement during bioassays is attributed to the complex opto-electronic interactions of incoming photonic signals at the nanomaterial interface. Research on the use of metals other than gold and silver for such purposes tends to extend the spectral window to observe luminescence enhancement effects. Such manifold increase in luminescence may be explained by the principles of plasmon coupling, directional emission led high collection efficiency, Rayleigh scattering and related opto-electronic events. The present review begins with a mechanistic description of important phenomena associated with metal-induced luminescence enhancement, particularly focusing on the origin of metal-enhanced luminescence. This review further analyses the hybrid nanostructure capabilities responsible for maintaining unique opto-electronic properties during bio-functionalisation. Current research trends in this area, future scope of this field for designing useful bioassays and concluding remarks are then discussed. - Highlights: • Nanomaterials significantly differ from their bulk counterparts. • Strong and pronounced photophysical effects at the metal surface provide opportunities for designing novel biosensors. • Metal-enhanced luminescence increases the quantum yield of luminescent reactions. • Under optimal conditions, plasmon coupling enhances the optical effects at the nanometal surface.

Metal-enhanced luminescence: Current trend and future perspectives- A review

Energy Technology Data Exchange (ETDEWEB)

Ranjan, Rajeev [Laboratory of Bioluminescent Biotechnologies, Department of Biophysics, Institute of Fundamental Biology and Biotechnology, Siberian Federal University, 79 Svobodny Prospect, Krasnoyarsk 660041 (Russian Federation); Esimbekova, Elena N., E-mail: esimbekova@yandex.ru [Laboratory of Bioluminescent Biotechnologies, Department of Biophysics, Institute of Fundamental Biology and Biotechnology, Siberian Federal University, 79 Svobodny Prospect, Krasnoyarsk 660041 (Russian Federation); Institute of Biophysics SB RAS, Federal Research Center “Krasnoyarsk Science Center SB RAS”, Akademgorodok 50/50, Krasnoyarsk 660036 (Russian Federation); Kirillova, Maria A. [Laboratory of Bioluminescent Biotechnologies, Department of Biophysics, Institute of Fundamental Biology and Biotechnology, Siberian Federal University, 79 Svobodny Prospect, Krasnoyarsk 660041 (Russian Federation); Kratasyuk, Valentina A. [Laboratory of Bioluminescent Biotechnologies, Department of Biophysics, Institute of Fundamental Biology and Biotechnology, Siberian Federal University, 79 Svobodny Prospect, Krasnoyarsk 660041 (Russian Federation); Institute of Biophysics SB RAS, Federal Research Center “Krasnoyarsk Science Center SB RAS”, Akademgorodok 50/50, Krasnoyarsk 660036 (Russian Federation)

2017-06-08

Optically enhanced biosensing strategies are prerequisites for developing miniature and highly sensitive multiplexed analytical platforms. Such smart biosensing systems are highly promising for use in the fields of biomedicine and environmental monitoring. Optical signal enhancement during bioassays is attributed to the complex opto-electronic interactions of incoming photonic signals at the nanomaterial interface. Research on the use of metals other than gold and silver for such purposes tends to extend the spectral window to observe luminescence enhancement effects. Such manifold increase in luminescence may be explained by the principles of plasmon coupling, directional emission led high collection efficiency, Rayleigh scattering and related opto-electronic events. The present review begins with a mechanistic description of important phenomena associated with metal-induced luminescence enhancement, particularly focusing on the origin of metal-enhanced luminescence. This review further analyses the hybrid nanostructure capabilities responsible for maintaining unique opto-electronic properties during bio-functionalisation. Current research trends in this area, future scope of this field for designing useful bioassays and concluding remarks are then discussed. - Highlights: • Nanomaterials significantly differ from their bulk counterparts. • Strong and pronounced photophysical effects at the metal surface provide opportunities for designing novel biosensors. • Metal-enhanced luminescence increases the quantum yield of luminescent reactions. • Under optimal conditions, plasmon coupling enhances the optical effects at the nanometal surface.

Luminescent Eosin Y–SiO2 hybrid nano and microrods prepared by sol–gel template method

International Nuclear Information System (INIS)

Secu, M.; Secu, C.E.; Sima, M.; Negrea, R.F.; Bartha, C.; Dinescu, M.; Damian, V.

2013-01-01

Sol–gel chemistry within the pores of a polycarbonate template membrane was used for the preparation of Eosin Y–SiO 2 hybrid nano- and microrods, using tetraethylorthosilicate [TEOS, Si(OC 2 H 5 ) 4 ] as the precursor in the presence of trifluoroacetic acid (TFA) catalyst. The ethanolic solution of Eosin-Y was added to the silica sol to trap dye molecules inside the SiO 2 gel network during the gelation. Structural and morphological characterization using scanning electron microscopy (SEM) and luminescence microscopy have shown the formation of rods with 200 nm and 1.2 μm diameter and about 30 μm length, exhibiting luminescence properties. Spectroscopic characterization has shown that the luminescence is due to Eosin-Y molecule in the xerogel porous network, surrounded by a solvation shell given mainly by the water. -- Highlights: • Sol–gel template method was used to prepare Eosin Y–SiO 2 hybrid rods-type structures. • Morphological characterization has shown nano- and microrods with luminescent properties. • Luminescence is due to Eosin-Y molecule surrounded by a solvation shell given by water

Scalable Direct Writing of Lanthanide-Doped KMnF3 Perovskite Nanowires into Aligned Arrays with Polarized Up-Conversion Emission.

Science.gov (United States)

Shi, Shuo; Sun, Ling-Dong; Xue, Ying-Xian; Dong, Hao; Wu, Ke; Guo, Shi-Chen; Wu, Bo-Tao; Yan, Chun-Hua

2018-05-09

The use of one-dimensional nano- and microstructured semiconductor and lanthanide materials is attractive for polarized-light-emission studies. Up-conversion emission from single-nanorod or anisotropic nanoparticles with a degree of polarization has also been discussed. However, microscale arrays of nanoparticles, especially well-aligned one-dimensional nanostructures as well as their up-conversion polarization characterization, have not been investigated yet. Herein, we present a novel and facile paradigm for preparing highly aligned arrays of lanthanide-doped KMnF 3 (KMnF 3 :Ln) perovskite nanowires, which are good candidates for polarized up-conversion emission studies. These perovskite nanowires, with a width of 10 nm and length of a few micrometers, are formed through the oriented attachment of KMnF 3 :Ln nanocubes along the [001] direction. By the employment of KMnF 3 :Ln nanowire gel as nanoink, a direct-writing method is developed to obtain diverse types of aligned patterns from the nanoscale to the wafer scale. Up-conversion emissions from the highly aligned nanowire arrays are polarized along the array direction with a polarization degree up to 60%. Taking advantage of microscopic nanowire arrays, these polarized up-conversion emissions should offer potential applications in light or information transportation.

On the role of non-bridging oxygen centers in the red luminescence emission from silicon nanocrystals

Energy Technology Data Exchange (ETDEWEB)

Borsella, Elisabetta; D' Amato, Rosaria; Fabbri, Fabio [ENEA, C. R. Frascati, via E. Fermi 45, 00044 Frascati, Roma (Italy); Falconieri, Mauro [ENEA, C. R. Casaccia, via Anguillarese 301, 00123 Roma (Italy); Trave, Enrico [Physical Chemistry Department, Universita Ca' Foscari Venezia, Dorsoduro 2137, 30123 Venezia (Italy); Bello, Valentina; Mattei, Giovanni [Physics Department, Universita degli Studi di Padova, Via Marzolo 8, 35131 Padova (Italy); Nie, Yaru; Wang, Dayang [Max Planck Institute of Colloids and Interfaces, 14424 Potsdam (Germany)

2011-03-15

The process responsible for visible-near infrared luminescence emission in Si nanostructures has been generating significant controversy for years. The debate has focused on whether light emission is originated by recombination of quantum confined excitons or by defects located at the surface. It is experimentally difficult to distinguish the two contributions since both are size-dependent. Moreover, all the studies were performed on different systems and consequently the comparisons were not free from ambiguities. Here we relate the spectroscopic properties of pyrolytic Si nanocrystals, aged in air, and after complete conversion to amorphous silica by alkali etching-assisted oxidation. The strong resemblance of the spectral and time decay behavior of the red PL emission in both systems (surface oxidized nanocrystalline Si and amorphous silica sample) indicates that this emission is dominated by defects in the silicon oxide. The strongly non-exponential time behavior of the photo-luminescence emission in both systems can be modeled as the sum of exponential decays from the emitting defects, thus ruling out the interpretation in terms of the so-called ''stretched exponential'' decay. Using this model we also obtained the emission energy and inhomogeneous linewidth of the luminescent defects, allowing us to identify them as the non-bridging oxygen hole centers. The emission energy of these defects depends strongly on their physical and chemical environment and can produce a shift apparently due to the size effect. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Amino-Functionalized Luminescent Metal-Organic Framework Test Paper for Rapid and Selective Sensing of SO2 Gas and Its Derivatives by Luminescence Turn-On Effect.

Science.gov (United States)

Wang, Meng; Guo, Lin; Cao, Dapeng

2018-03-06

Rapid and selective sensing of sulfur dioxide (SO 2 ) gas has attracted more and more attention because SO 2 not only causes environmental pollution but also severely affects the health of human beings. Here we report an amino-functionalized luminescent metal-organic framework (MOF) material (i.e., MOF-5-NH 2 ) and further investigate its sensing property for SO 2 gas and its derivatives as a luminescent probe. The results indicate that the MOF-5-NH 2 probe can selectively and sensitively sense SO 2 derivatives (i.e., SO 3 2- ) in real time by a luminescence turn-on effect with a lower detection limit of 0.168 ppm and a response time of less than 15 s. Importantly, the luminescence turn-on phenomenon can be observed by the naked eye. We also assembled MOF-5-NH 2 into a test paper to achieve the aim of portable detection, and the lower-limit concentration of the test paper for sensing SO 2 in real time was found to be about 0.05 ppm. Moreover, MOF-5-NH 2 also shows good anti-interference ability, strong luminescence stability, and reusability, which means that this material is an excellent sensing candidate. The amino functionalization may also provide a modification strategy to design luminescent sensors for other atmospheric pollutants.

Single fiber temperature probe configuration using anti-Stokes luminescence from Cr:GdAlO3

Science.gov (United States)

Eldridge, Jeffrey I.

2018-06-01

Single-photon excitation of anti-Stokes-shifted emission from a thermographic phosphor allows operation of a luminescence decay-based single fiber temperature probe with negligible interference from background fiber-generated Raman scattering. While single fiber probe configurations for luminescence-based fiber optic thermometers offer advantages of simple design, compactness, and superior emission light collection efficiency, their effective use has been limited by interference from Raman scattering in the fiber probe and excitation delivery fiber that produces distortion of the luminescence decay that follows the excitation pulse. The near elimination of interference by background fiber-generated Raman scattering was demonstrated by incorporating a Cr-doped GdAlO3 (Cr:GdAlO3) thermographic phosphor as the sensing element at the end of a single fiber luminescence decay-based thermometer and detecting anti-Stokes-shifted luminescence centered at 542 or 593 nm produced by 695 nm excitation. Measurements were performed using both silica (up to 1150 °C) and single-crystal YAG (up to 1200 °C) fiber-based thermometers. Selection of emission detection centered at 542 nm greatly benefited the YAG fiber probe measurements by practically eliminating detection of otherwise significant luminescence from Cr3+ impurities in the YAG fiber. For both the silica and YAG fiber probes, the relative benefit of adopting single-photon excitation of anti-Stokes-shifted luminescence was evaluated by comparison with results obtained by conventional 532 nm excitation of Stokes-shifted luminescence.

Luminescence studies on phosphor screens

Energy Technology Data Exchange (ETDEWEB)

Panayiotakis, G; Nomikos, C; Bakas, A; Proimos, B [Medical Physics Department, University of Patras, 265 00 Patras, Greece (Greece)

1994-12-31

We report our results on x-ray phosphor screens prepared of some new materials focusing attention on their efficiency under fluoroscopy conditions, on optimization conditions and on comparisons among the various materials. All data are presented in absolute values. A theoretical model is presented, that takes into account the granular structure of the screens, permitting the explanation and prediction of the luminescence properties of the screens. (authors). 12 refs, 3 figs.

Improved ferroelectric/piezoelectric properties and bright green/UC red emission in (Li,Ho)-doped CaBi4Ti4O15 multifunctional ceramics with excellent temperature stability and superior water-resistance performance.

Science.gov (United States)

Xiao, Ping; Guo, Yongquan; Tian, Mijie; Zheng, Qiaoji; Jiang, Na; Wu, Xiaochun; Xia, Zhiguo; Lin, Dunmin

2015-10-21

Multifunctional materials based on rare earth ion doped ferro/piezoelectrics have attracted considerable attention in recent years. In this work, new lead-free multifunctional ceramics of Ca1-x(LiHo)x/2Bi4Ti4O15 were prepared by a conventional solid-state reaction method. The great multi-improvement in ferroelectricity/piezoelectricity, down/up-conversion luminescence and temperature stability of the multifunctional properties is induced by the partial substitution of (Li0.5Ho0.5)(2+) for Ca(2+) ions in CaBi4Ti4O15. All the ceramics possess a bismuth-layer structure, and the crystal structure of the ceramics is changed from a four layered bismuth-layer structure to a three-layered structure with the level of (Li0.5Ho0.5)(2+) increasing. The ceramic with x = 0.1 exhibits simultaneously, high resistivity (R = 4.51 × 10(11)Ω cm), good piezoelectricity (d33 = 10.2 pC N(-1)), high Curie temperature (TC = 814 °C), strong ferroelectricity (Pr = 9.03 μC cm(-2)) and enhanced luminescence. These behaviours are greatly associated with the contribution of (Li0.5Ho0.5)(2+) in the ceramics. Under the excitation of 451 nm light, the ceramic with x = 0.1 exhibits a strong green emission peak centered at 545 nm, corresponding to the transition of the (5)S2→(5)I8 level in Ho(3+) ions, while a strong red up-conversion emission band located at 660 nm is observed under the near-infrared excitation of 980 nm at room temperature, arising from the transition of (5)F5→(5)I8 levels in Ho(3+) ions. Surprisingly, the excellent temperature stability of ferroelectricity/piezoelectricity/luminescence and superior water-resistance behaviors of piezoelectricity/luminescence are also obtained in the ceramic with x = 0.1. Our study suggests that the present ceramics may have potential applications in advanced multifunctional devices at high temperature.

Luminescence and Magnetic Properties of Tb(III) Complexes with TETA and Synergistic Effect by 1,10-Phenanthroline

International Nuclear Information System (INIS)

Kang, Jung Youl; Shin, Su jeong; Kim, Jae Kwan; Park, Kyoung Chan

2016-01-01

Two Tb(III) complexes, [Tb(TETA)]− and [Tb(TETA)(phen)]− (TETA = 1,4,8,11-tetraazacyclotetradecane-1,4,8,11-tetraacetate and phen=1,10-phenanthroline), were synthesized and their luminescence ("5D_4 → "7F_=_0_-_6 transitions) and magnetic properties were examined. The photoluminescence (PL) quantum yield of [Tb(TETA)(phen)]− (Q = 0.47) was significantly higher than that of [Tb(TETA)]− (Q = 0.006). The dramatic increase (78 x) in green luminescence was attributed to intramolecular energy transfer from phen to Tb(III). The energy transfer rate according to Dexter theory was found to be approximately 1011s−1. The temperature dependence of the molar susceptibilities confirmed that the two complexes behave as paramagnets obeying the Curie–Weiss law. In addition, the field-dependent magnetization of the two complexes measured in the −70 to + 70 kOe range at T=1.8K fitted well with the Brillouin function with the following values: g _e_f_f=1.5, μ B =9.27×10−21 emu, and J=6. These results provide new insights into the development of lanthanide metal complexes with tetraaza

Luminescence and Magnetic Properties of Tb(III) Complexes with TETA and Synergistic Effect by 1,10-Phenanthroline

Energy Technology Data Exchange (ETDEWEB)

Kang, Jung Youl; Shin, Su jeong; Kim, Jae Kwan; Park, Kyoung Chan [Hanbat National University, Daejeon (Korea, Republic of)

2016-09-15

Two Tb(III) complexes, [Tb(TETA)]− and [Tb(TETA)(phen)]− (TETA = 1,4,8,11-tetraazacyclotetradecane-1,4,8,11-tetraacetate and phen=1,10-phenanthroline), were synthesized and their luminescence ({sup 5}D{sub 4} → {sup 7}F{sub =0-6} transitions) and magnetic properties were examined. The photoluminescence (PL) quantum yield of [Tb(TETA)(phen)]− (Q = 0.47) was significantly higher than that of [Tb(TETA)]− (Q = 0.006). The dramatic increase (78 x) in green luminescence was attributed to intramolecular energy transfer from phen to Tb(III). The energy transfer rate according to Dexter theory was found to be approximately 1011s−1. The temperature dependence of the molar susceptibilities confirmed that the two complexes behave as paramagnets obeying the Curie–Weiss law. In addition, the field-dependent magnetization of the two complexes measured in the −70 to + 70 kOe range at T=1.8K fitted well with the Brillouin function with the following values: g {sub eff}=1.5, μ B =9.27×10−21 emu, and J=6. These results provide new insights into the development of lanthanide metal complexes with tetraaza.

Luminescence properties and energy transfer processes in YAG:Yb,Er single crystalline films

International Nuclear Information System (INIS)

Zorenko, Yu.; Gorbenko, V.; Savchyn, V.; Batentschuk, M.; Osvet, A.; Brabec, C.

2013-01-01

The paper is dedicated to the study of the optical properties of YAG:Yb,Er single-crystalline films (SCF) grown by liquid phase epitaxy. The absorption, cathodoluminescence and time-resolved photoluminescence spectra and photoluminescence decay curves were measured for the SCFs with different doping levels of Er 3+ (from 0.6 to 4.2 at.%) and Yb 3+ (from 0.1 to 0.6 at.%). The spectra, excited by synchrotron radiation in the fundamental absorption range of the YAG and in the intraionic absorption bands of both dopants, reveal energy transfer from the YAG host to the Er 3+ and Yb 3+ ions and between these ions. -- Highlights: •Growth of YAG:Yb,Er single crystalline films by LPE method. •Peculiarities of luminescence of YAG:Yb,Er films with different Er–Yb content. •Yb–Er energy transfer processes in YAG hosts

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.

Defect-mediated photoluminescence up-conversion in cadmium sulfide nanobelts (Conference Presentation)

Science.gov (United States)

Morozov, Yurii; Kuno, Masaru K.

2017-02-01

The concept of optical cooling of solids has existed for nearly 90 years ever since Pringsheim proposed a way to cool solids through the annihilation of phonons via phonon-assisted photoluminescence (PL) up-conversion. In this process, energy is removed from the solid by the emission of photons with energies larger than those of incident photons. However, actually realizing optical cooling requires exacting parameters from the condensed phase medium such as near unity external quantum efficiencies as well as existence of a low background absorption. Until recently, laser cooling has only been successfully realized in rare earth doped solids. In semiconductors, optical cooling has very recently been demonstrated in cadmium sulfide (CdS) nanobelts as well as in hybrid lead halide perovskites. For the former, large internal quantum efficiencies, sub-wavelength thicknesses, which decrease light trapping, and low background absorption, all make near unity external quantum yields possible. Net cooling by as much as 40 K has therefore been possible with CdS nanobelts. In this study, we describe a detailed investigation of the nature of efficient anti-Stokes photoluminescence (ASPL) in CdS nanobelts. Temperature-dependent PL up-conversion and optical absorption studies on individual NBs together with frequency-dependent up-converted PL intensity spectroscopies suggest that ASPL in CdS nanobelts is defect-mediated through involvement of defect levels below the band gap.

Synthesis and luminescence in sol–gel auto-combustion ...

Indian Academy of Sciences (India)

2017-11-14

Nov 14, 2017 ... Eu-doped CaSnO3 showed broad blue emission centred about 434 nm, a ... symmetry [5]. Recently, luminescence properties of rare-earth-cation- ... able attention due to their abundant emission colours based on their 4f–4f or ...

OPTICAL AND DYNAMIC PROPERTIES OF UNDOPED AND DOPED SEMICONDUCTOR NANOSTRUCTURES

Energy Technology Data Exchange (ETDEWEB)

Grant, C D; Zhang, J Z

2007-09-28

This chapter provides an overview of some recent research activities on the study of optical and dynamic properties of semiconductor nanomaterials. The emphasis is on unique aspects of these properties in nanostructures as compared to bulk materials. Linear, including absorption and luminescence, and nonlinear optical as well as dynamic properties of semiconductor nanoparticles are discussed with focus on their dependence on particle size, shape, and surface characteristics. Both doped and undoped semiconductor nanomaterials are highlighted and contrasted to illustrate the use of doping to effectively alter and probe nanomaterial properties. Some emerging applications of optical nanomaterials are discussed towards the end of the chapter, including solar energy conversion, optical sensing of chemicals and biochemicals, solid state lighting, photocatalysis, and photoelectrochemistry.

Performance of Differential-Phase-Shift Keying Protocol Applying 1310 nm Up-Conversion Single-Photon Detector

International Nuclear Information System (INIS)

Chen-Xu, Feng; Rong-Zhen, Jiao; Wen-Han, Zhang

2008-01-01

The performance of the differential-phase-shift keying (DPSK) protocol applying a 1310 nm up-conversion single-photon detector is analysed. The error rate and the communication rate as a function of distance for three quantum key distribution protocols, the Bennett–Brassard 1984, the Bennett–Brassard–Mermin 1992, and the DPSK, are presented. Then we compare the performance of these three protocols using the 1310nm up-conversion detector. We draw the conclusion that the DPSK protocol applying the detector has significant advantage over the other two protocols. Longer transmission distance and lower error rate can be achieved. (general)

Fabrication of Up-Conversion Phosphor Films on Flexible Substrates Using a Nanostructured Organo-Silicon.

Science.gov (United States)

Jeon, Young-Sun; Kim, Tae-Un; Kim, Seon-Hoon; Lee, Young-Hwan; Choi, Pil-Son; Hwang, Kyu-Seog

2018-03-01

Up-conversion phosphors have attracted considerable attention because of their applications in solid-state lasers, optical communications, flat-panel displays, photovoltaic cells, and biological labels. Among them, NaYF4 is reported as one of the most efficient hosts for infrared to visible photon up-conversion of Yb3+ and Er3+ ions. However, a low-temperature method is required for industrial scale fabrication of photonic and optoelectronic devices on flexible organic substrates. In this study, hexagonal β-NaYF4: 3 mol% Yb3+, 3 mol% Er3+ up-conversion phosphor using Ca2+ was prepared by chemical solution method. Then, we synthesized a nanostructured organo-silicon compound from methyl tri-methoxysilane and 3-glycidoxy-propyl-trimethoxy-silane. The transmittance of the organo-silicon compound was found to be over 90% in the wavelength range of 400~1500 nm. Then we prepared a fluoride-based phosphor paste by mixing the organo-silicon compound with Na(Ca)YF4:Yb3+, Er3+. Subsequently, this paste was coated on polyethylene terephthalate, followed by heat-treatment at 120 °C. The visible emission of the infrared detection card was found to be at 655 nm and 661 nm an excitation wavelength of 980 nm.

A luminescent metal-organic framework for sensing methanol in ethanol solution.

Science.gov (United States)

Jin, Zhao; He, Hongming; Zhao, Huanyu; Borjigin, Tsolmon; Sun, Fuxing; Zhang, Daming; Zhu, Guangshan

2013-10-07

A new luminescent Zn-MOF has been synthesized under hydrothermal condition using a semi-rigid ligand H3pcoip (4-(2-carboxyphenoxy)isophthalic acid) is reported. The luminescence properties of 1 in methanol, ethanol, and water have been investigated. Interestingly, compound 1 has a unique response to methanol compared to ethanol and water. Moreover, 1 displays a turn-on switching property triggered by methanol solvent molecules and a high sensitivity towards methanol concentration as low as 2 × 10(-7) (V(MeOH)/V(total)) in ethanol solution. The results indicate that the Zn-MOF has potential application as a sensor for detecting methanol in ethanol solution with excellent selectivity and high sensitivity.

Recent Advance of Biological Molecular Imaging Based on Lanthanide-Doped Upconversion-Luminescent Nanomaterials

Directory of Open Access Journals (Sweden)

Yuanzeng Min

2014-02-01

Full Text Available Lanthanide-doped upconversion-luminescent nanoparticles (UCNPs, which can be excited by near-infrared (NIR laser irradiation to emit multiplex light, have been proven to be very useful for in vitro and in vivo molecular imaging studies. In comparison with the conventionally used down-conversion fluorescence imaging strategies, the NIR light excited luminescence of UCNPs displays high photostability, low cytotoxicity, little background auto-fluorescence, which allows for deep tissue penetration, making them attractive as contrast agents for biomedical imaging applications. In this review, we will mainly focus on the latest development of a new type of lanthanide-doped UCNP material and its main applications for in vitro and in vivo molecular imaging and we will also discuss the challenges and future perspectives.

Luminescence properties of common salt (NaCl available in Nigeria for use as accident dosimeter in radiological emergency situation

Directory of Open Access Journals (Sweden)

Janet Ayobami Ademola

2017-04-01

Full Text Available In the event of a radiological accident or attack, it is important to assess and quantify radiation dose to the population. This could be done using materials in the vicinity that are sensitive to ionizing radiation. Common salt (NaCl is known to be a sensitive thermoluminescence (TL phosphor. Luminescence properties of common salt (NaCl used in Nigeria were investigated using an automated luminescence reader Risø TL/OSL-DA-15, with attention focused more on the Optically Stimulated Luminescence (OSL. Strong radiation-induced TL and OSL signals were observed. The TL peaks occurred at about 100 °C, 240 °C and 280 °C. The dose response of both the TL and OSL signals showed a linear relationship. From the OSL pulse anneal curve with TL curve, a preheat temperature of 190 °C for 10 s was found adequate for the OSL measurements. There was no significant difference in the OSL decay for stimulation temperatures of 100 and 120 °C. Fading experiment over a storage period of 14 days showed about 13 and 3% decrease in the OSL signal of sample 1 and sample 2, respectively. The ratios of measured to given dose for dose recovery test were within ±19% of unity. Within the limit of error the samples could be used as a complementary emergency dosimeter in radiological accident situation.

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

Persistent luminescence and thermoluminescence of UV/VIS -irradiated SrAl2O4: Eu2+, Dy3+ phosphor

International Nuclear Information System (INIS)

Pereyda-Pierre, C.; Meléndrez, R.; García, R.; Pedroza-Montero, M.; Barboza-Flores, M.

2011-01-01

The persistent luminescence and thermoluminescence properties of SrAl 2 O 4 : Eu 2+ , Dy 3+ phosphors excited with UV–VIS light in the 200–500 nm region were investigated. The thermoluminescence glow curve was found to be composed of peaks around 70, 125 and 245 °C. The persistent luminescence and thermoluminescence excitation spectra exhibited a broad band around 300–500 nm centered at 400 and 420 nm respectively. A linear behavior of the integrated thermoluminescence intensity and persistent luminescence versus irradiation time was found for the first 60 s. The charge detrapping from the 70 °C trapping levels was the major contributor to the observed persistent luminescence at room temperature. The SrAl 2 O 4 : Eu 2+ , Dy 3+ phosphors have suitable properties to be applied as storage and persistent luminescence UV–VIS irradiation dose phosphor. -- Highlights: ► SrAl 2 O 4 :Eu 2+ , Dy 3+ persistent luminescence and thermoluminescence was measured. ► The phosphor was irradiated with UV–VIS photons in the 200–500 nm wavelength range. ► SrAl 2 O 4 :Eu 2+ , Dy 3+ behaves adequately as persistent and storage UV–VIS dosimeter. ► The persistent luminescence dosimetry does not require heat or light stimulation.

Systematic development of new thermoluminescence and optically stimulated luminescence materials

Energy Technology Data Exchange (ETDEWEB)

Yukihara, E.G., E-mail: eduardo.yukihara@okstate.edu [Physics Department, 145 Physical Sciences II, Oklahoma State University, Stillwater, OK 74078 (United States); Milliken, E.D.; Oliveira, L.C. [Physics Department, 145 Physical Sciences II, Oklahoma State University, Stillwater, OK 74078 (United States); Orante-Barron, V.R. [Departamento de Investigacion en Polimeros y Materiales, Universidad de Sonora, Hermosillo, Sonora 83000, Mexico (Mexico); Jacobsohn, L.G. [Center for Optical Materials Science and Engineering Technologies (COMSET), and School of Materials Science and Engineering, Clemson University, Clemson, SC (United States); Blair, M.W. [Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

2013-01-15

This paper presents an overview of a systematic study to develop new thermoluminescence (TL) and optically stimulated luminescence (OSL) materials using solution combustion synthesis (SCS) for applications such as personal OSL dosimetry, 2D dose mapping, and temperature sensing. A discussion on the material requirements for these applications is included. We present X-ray diffraction (XRD) data on single phase materials obtained with SCS, as well as radioluminescence (RL), TL and OSL data of lanthanide-doped materials. The results demonstrate the possibility of producing TL and OSL materials with sensitivity similar to or approaching those of commercial TL and OSL materials used in dosimetry (e.g., LiF:Mg,Ti and Al{sub 2}O{sub 3}:C) using SCS. The results also show that the luminescence properties can be improved by Li co-doping and annealing. The presence of an atypical TL background and anomalous fading are discussed and deserve attention in future investigations. We hope that these preliminary results on the use of SCS for production of TL and OSL materials are helpful to guide future efforts towards the development of new luminescence materials for different applications. - Highlights: Black-Right-Pointing-Pointer TL and OSL material produced with sensitivity similar to commercial materials. Black-Right-Pointing-Pointer Luminescence properties improved by Li co-doping and annealing. Black-Right-Pointing-Pointer The presence of atypical TL background and anomalous fading observed.

Photoelectric conversion and electrochromic properties of lutetium tetrakis(tert-butyl)bisphthalocyaninate

International Nuclear Information System (INIS)

Hu, Andrew Teh; Hu Tenyi; Liu Lungchang

2003-01-01

Both photoelectric and electrochromic effects on lutetium tetrakis(tert-butyl)bisphthalocyaninate (Lu(TBPc) 2 ) have been carried out in this study. Lu(TBPc) 2 is known for its electrochromic performance, but its photoelectric effect has not mentioned in the literature. The electrochromic properties of Lu(TBPc) 2 have been measured by cyclic voltammetry (CV) and UV-Vis spectrometer at the same time. It takes less than 1.5 s for the color to change from red to green under 0.9 V. Its cycle life is at least over 500 times. Furthermore, we also investigate its photoelectric conversion properties. Its photoelectric cell exhibits a positive photo-electricity conversion effect with a short-circuit photocurrent (46.4 μA/cm 2 ) under illumination of white light (1.201 mW/cm 2 )

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)

Mechanism of band-edge luminescence in cuprous iodide single crystals

International Nuclear Information System (INIS)

Gao, Pan; Gu, Mu; Liu, Xi; Liu, Bo; Zheng, Yan-Qing; Shi, Er-Wei; Shi, Jun-Yan; Zhang, Guo-bin

2014-01-01

Highlights: • The luminescence properties of CuI crystals are influenced by the quality of the as-grown crystals. • The emission peaks of free-exciton and bound-exciton are observed in the CuI single crystals. • The ultrafast component luminescence is warranted to the donor-acceptor pair recombination. • The exciton absorption and electron excitation multiplication processes were observed in CuI. - Abstract: The photoluminescence spectra of CuI crystals using synchrotron radiation as an excitation light source were obtained at 60 K. The emission peaks at 405, 415, 420 and 443 nm were observed. The possible origins of these peaks were discussed by the temperature dependence of luminescence spectra for CuI material. Meanwhile, the photoluminescence spectra of CuI powder with different excitation intensity were measured and the ultrafast luminescence component of CuI crystals was warranted to be attributed to the recombination of donor acceptor pair. Furthermore, the excitation process was studied by measuring the photoluminescence excitation spectra of CuI crystals and powder

Effect of microwave treatment on the luminescence properties of CdS and CdTe:Cl Single Crystals

International Nuclear Information System (INIS)

Red’ko, R. A.; Budzulyak, S. I.; Korbutyak, D. V.; Lotsko, A. P.; Vakhnyak, N. D.; Demchyna, L. A.; Kalytchuk, S. M.; Konakova, R. V.; Milenin, V. V.; Bykov, Yu. V.; Egorov, S. V.; Eremeev, A. G.

2015-01-01

The effect of microwave radiation on the luminescence properties of CdS and CdTe:Cl single crystals is studied. It is established that the exposure of these semiconductors to short-term (≤30 s) microwave radiation substantially modifies their impurity and defect structure. The mechanisms of transformation of the defect subsystem of II–VI single crystals upon microwave treatment are discussed. It is shown that the experimentally observed changes are defined by the nonthermal effects of microwave radiation at a power density of 7.5 W cm –2 ; at 90 W cm –2 , nonthermal effects are prevailing

Preparation and characterization of bifunctional dendrimer modified Fe{sub 3}O{sub 4}/CdTe nanoparticles with both luminescent and superparamagnetic properties

Energy Technology Data Exchange (ETDEWEB)

Wang, Xiuling, E-mail: wxling_self@163.com [Department of Chemical and Biological Engineering, Suzhou University of Science and Technology, Suzhou 215009 (China); Gu, Yinjun; Dong, Shuling [Department of Chemical and Biological Engineering, Suzhou University of Science and Technology, Suzhou 215009 (China); Zhao, Qin [School of Chemistry and Chemical Engineering, Nantong University, Nantong, Jiangsu 226019 (China); Liu, Yongjian [Department of Chemical and Biological Engineering, Suzhou University of Science and Technology, Suzhou 215009 (China)

2015-10-15

Highlights: • The fluorescent superparamagnetic dendrimeric Fe{sub 3}O{sub 4}/CdTe nanoparticles are synthesized in this paper. • The synthesized nanocomposites maintain excellent magnetic properties. • The synthesized nanocomposites maintain highly luminescent markers with narrow emission bands. - Abstract: Magnetic nanoparticles Fe{sub 3}O{sub 4} were prepared by hydrothermal coprecipitation of ferric and ferrous ions using NaOH. The surface modification of Fe{sub 3}O{sub 4} nanoparticle by dendrimers has rendered the nanoparticle surface with enriched amine groups which facilitated the adsorption and conjugation of thioglycolic acid (TGA) modified CdTe quantum dots to form a stable hybrid nanostructure. Three generations (first generation: G0F, second generation: G1F, third generation: G3F) of bifunctional dendrimeric Fe{sub 3}O{sub 4}/CdTe nanoparticles were successfully prepared using this technique and characterized by microscopy. The optical and magnetic properties of the dendrimeric Fe{sub 3}O{sub 4}/CdTe nanoparticle were also investigated. The microscopic study reveals 3 different sizes for 3 generations, 16 nm (G0F), 31 nm (G1F) and 47 nm (G3F). Among three generations of nanoparticles, the G1F has the best optical property with a luminescent quantum yield of 25.6% and the G0F has the best magnetic property with a saturation magnetization of 19.3 emμ/g.

Crack luminescence as an innovative method for detection of fatigue damage

Directory of Open Access Journals (Sweden)

R. Makris

2018-04-01

Full Text Available Conventional non-destructive testing methods for crack detection provide just a snapshot of fatigue crack evolution at a specific location in the moment of examination. The crack luminescence coating realizes a clear visibility of the entire crack formation. The coating consists of two layers with different properties and functions. The bottom layer emits light as fluorescence under UV radiation. The top layer covers the fluorescing one and prevents the emitting of light in case of no damage at the surface. Several different experiments show that due to the sensitive coating even the early stage of crack formation can be detected. That makes crack luminescence helpful for investigating the incipient crack opening behavior. Cracks can be detected and observed during operation of a structure, making it also very interesting for continuous monitoring. Crack luminescence is a passive method and no skilled professionals are necessary to detect cracks, as for conventional methods. The luminescent light is clearly noticeable by unaided eye observations and also by standard camera equipment, which makes automated crack detection possible as well. It is expected that crack luminescence can reduce costs and time for preventive maintenance and inspection.

On the luminescence of perovskite type rare earth gallates

International Nuclear Information System (INIS)

Jianmei, Y.; Qingyuan, W.; Shuzhen, L.; Lianren, S.; Mingyu, C.

1985-01-01

It has been reported that perovskite type lanthanum gallates may be a good host material for laser and luminescence, but in the rare earth gallates studied, the numbers of perovskite type are less than that of the garnet type and there is less report on their spectroscopic properties in the literature. In this paper synthesis and spectroscopic properties of these compounds are studied

Preparation and Luminescent Properties of the antibacterial materials of the La3+ Doped Sm3+-Hydroxyapatite

Science.gov (United States)

Lv, Yuguang; Shi, Qi; Jin, Yuling; Ren, Hengxin; Qin, Yushan; Wang, Bo; Song, Shanshan

2018-03-01

In this paper, the La3+-doped Sm3+ hydroxyapatite (La/Sm/HAP) complexes were prepared by a precipitation method. The sample was defined by IR spectra, fluorescence spectra and X ray diffraction analysis et al. The structure of complexes were discussed. The emission wavelength of heat treatment of Sm3+ do not change, but will affect the intensity of the peak Sm3+ luminescence properties and the occupy hydroxyapatite in the lattice Ca( II )and Ca( I ) loci with Sm3+ doped concentration and the proportion of the sintering temperature change and change: The nano hydroxyapatite complex of the La3+ doped samarium obtain the good fluorescence intensity, by La3+ doping content of Sm3+ were hydroxyapatite 6% (La3+, Sm3+ mole ratio) device. The complex of La3+ doped samarium HAP have Stable chemical property, fluorescence property and excellent biological activity. The ligand HAP absorbs energy or captures an electron-hole pair and then transfers it to the lanthanide ions. The catalytic activity influence of the La3+-doped Sm3+hydroxyapatite was discussed, the La/Sm/HAP had excellent antibacterial property, which used as potential biological antibacterial material.

NIR luminescent Er{sup 3+}/Yb{sup 3+} co-doped SiO{sub 2}-ZrO{sub 2} nanostructured planar and channel waveguides: Optical and structural properties

Energy Technology Data Exchange (ETDEWEB)

Cunha, Cesar dos Santos [Departamento de Quimica, Faculdade de Filosofia, Ciencias e Letras de Ribeirao Preto, Universidade de Sao Paulo, Av. Bandeirantes, 3900, 14040-901, Ribeirao Preto/SP (Brazil); Ferrari, Jefferson Luis [Grupo de Pesquisa em Quimica de Materiais - (GPQM), Departamento de Ciencias Naturais, Universidade Federal de Sao Joao Del Rei, Campus Dom Bosco, Praca Dom Helvecio, 74, 36301-160, Sao Joao Del Rei, MG (Brazil); Oliveira, Drielly Cristina de [Departamento de Quimica, Faculdade de Filosofia, Ciencias e Letras de Ribeirao Preto, Universidade de Sao Paulo, Av. Bandeirantes, 3900, 14040-901, Ribeirao Preto/SP (Brazil); Maia, Lauro June Queiroz [Grupo Fisica de Materiais, Instituto de Fisica, UFG, Campus Samambaia, Caixa Postal 131, 74001-970, Goiania/GO (Brazil); Gomes, Anderson Stevens Leonidas [Departamento de Fisica, Universidade Federal de Pernambuco, Cidade Universitaria, Recife/PE, 50670-901 (Brazil); Ribeiro, Sidney Jose Lima [Laboratorio de Materiais Fotonicos, Instituto de Quimica, UNESP, Caixa Postal 355, 14801-970, Araraquara/SP (Brazil); and others

2012-09-14

Optical and structural properties of planar and channel waveguides based on sol-gel Er{sup 3+} and Yb{sup 3+} co-doped SiO{sub 2}-ZrO{sub 2} are reported. Microstructured channels with high homogeneous surface profile were written onto the surface of multilayered densified films deposited on SiO{sub 2}/Si substrates by a femtosecond laser etching technique. The densification of the planar waveguides was evaluated from changes in the refractive index and thickness, with full densification being achieved at 900 Degree-Sign C after annealing from 23 up to 500 min, depending on the ZrO{sub 2} content. Crystal nucleation and growth took place together with densification, thereby producing transparent glass ceramic planar waveguides containing rare earth-doped ZrO{sub 2} nanocrystals dispersed in a silica-based glassy host. Low roughness and crack-free surface as well as high confinement coefficient were achieved for all the compositions. Enhanced NIR luminescence of the Er{sup 3+} ions was observed for the Yb{sup 3+}-codoped planar waveguides, denoting an efficient energy transfer from the Yb{sup 3+} to the Er{sup 3+} ion. Highlights: Black-Right-Pointing-Pointer Sol-gel high NIR luminescent nanostructured planar and channel waveguides. Black-Right-Pointing-Pointer Microstructured channels written by a femtosecond laser etching technique. Black-Right-Pointing-Pointer Transparent glass ceramic with rare earth-doped ZrO{sub 2} nanocrystals in a silica host. Black-Right-Pointing-Pointer Enhanced NIR luminescence, efficient energy transfer from the Yb{sup 3+} to the Er{sup 3+} ion. Black-Right-Pointing-Pointer New planar channel waveguides to be applied as EDWA in the C telecommunication band.

Luminescence performance of Eu -doped lead-free zinc phosphate ...

Indian Academy of Sciences (India)

luminescence properties in combination with its non-toxicity and non-hygroscopic nature ..... two colours will appear to the human eye as one colour and. Figure 10. ... [4] Mariappam C R, Govindaraj G, Rathan S V and Vijaya. Prakash G 2005 ...

Up-conversion routines of Er{sup 3+}–Yb{sup 3+} doped Y{sub 6}O{sub 5}F{sub 8} and YOF phosphors

Energy Technology Data Exchange (ETDEWEB)

Park, Sangmoon, E-mail: spark@silla.ac.kr [Center for Green Fusion Technology and Department of Engineering in Energy & Applied Chemistry, Silla University, Busan 617-736 (Korea, Republic of); Yang, Wonseok; Park, Chu-Young; Noh, Minhee; Choi, Seulki [Center for Green Fusion Technology and Department of Engineering in Energy & Applied Chemistry, Silla University, Busan 617-736 (Korea, Republic of); Park, Dahye; Jang, Ho Seong; Cho, So-Hye [Center for Materials Architecturing, Institute of Multidisciplinary Convergence of Materials, Korea Institute of Science and Technology, Seoul 130-650 (Korea, Republic of)

2015-11-15

Highlights: • Single-phase optical materials of Y{sub 6}O{sub 5}F{sub 8}:Er and YOF:Er were prepared. • Effective spectral converting properties were observed in Y{sub 6}O{sub 5}F{sub 8}:Er,Yb. • 980 nm diode laser was irradiated for up-converting analysis. • A multi-photon process in the phosphors was investigated. - Abstract: Optical materials composed of a Y{sub 6(1−p−q)}Er{sub 6p}Yb{sub 6q}O{sub 5}F{sub 8} (p = 0.001–0.1, q = 0.005–0.1) solid solution with Y{sub 0.99}Er{sub 0.01}OF were prepared via a solid-state reaction using excess NH{sub 4}F flux at 950 °C for 30 min. X-ray diffraction patterns of Y{sub 6(1−p−q)}Er{sub 6p}Yb{sub 6q}O{sub 5}F{sub 8} and Y{sub 0.99}Er{sub 0.01}OF were compared upon altering the synthesis temperature and the molar ratio of the NH{sub 4}F flux to the Y{sup 3+} (Er{sup 3+}, Yb{sup 3+}) ions. The effective spectral-conversion properties of Er{sup 3+} and Er{sup 3+}–Yb{sup 3+} ions in Y{sub 6}O{sub 5}F{sub 8} phosphors were monitored during excitation with a 980 nm wavelength diode-laser. Selection of appropriate Er{sup 3+} and/or Yb{sup 3+} concentrations in the Y{sub 6}O{sub 5}F{sub 8} structure led to achievement of the desired up-conversion emission, from the green to the red regions of the spectra. Furthermore, the mechanism of up-conversion in the phosphors was described by an energy-level schematic. Up-conversion emission spectra and the dependence of the emission intensity on pump power (between 193 and 310 mW) in the Y{sub 6(0.995−q)}Er{sub 0.03}Yb{sub 6q}O{sub 5}F{sub 8} phosphors were also investigated.

Yellow stimulated luminescence from potassium feldspar: Observations on its suitability for dating

International Nuclear Information System (INIS)

Lauer, T.; Krbetschek, M.; Mauz, B.; Frechen, M.

2012-01-01

Yellow stimulated luminescence (Y-OSL) is the light detected from potassium-rich feldspars at 410 nm under stimulation by a yellow light source emitting 590 nm. The investigation of this study aimed at understanding basic luminescence physics of Y-OSL in order to assess the suitability of the technique for dating. The Y-OSL signal properties tested were signal intensity, thermal assistance, thermal stability, sensitivity to daylight and the suitability of a single aliquot regenerative (SAR) protocol to be employed for equivalent dose (D e ) estimation. D e measurements were conducted on samples of Holocene, last glacial and Tertiary age. The tests were undertaken on sedimentary feldspar separates extracted from aeolian, fluvial and coastal deposits. Results from experiments show that the signal intensity increases by measuring Y-OSL at elevated temperature suggesting thermal assistance characteristics similar to infrared stimulated luminescence (IRSL). The yellow stimulated signal remains unaffected by preheat temperatures up to ∼200 °C suggesting higher thermal stability than the IRSL signal. The Y-OSL signal is less light sensitive than the IRSL signal and D e residuals obtained from modern samples are up to 7 Gy indicating suitability of the technique for ‘older’ and well-bleached sediments. The dose recovery tests successfully recovered the given dose if the specific light sensitivity of Y-OSL is taken into account. For every sample Y-OSL D e values obtained by a single aliquot regenerative dose protocol (SAR) are higher than those obtained by an IRSL SAR approach. From these results we infer high thermal stability and a minimal anomalous fading of the Y-OSL signal. We conclude that Y-OSL has a high potential to date Quaternary sediments that were sufficiently bleached in nature.

Luminescent hybrid materials based on (8-hydroxyquinoline)-substituted metal-organic complexes and lead-borate glasses

Science.gov (United States)

Petrova, Olga B.; Anurova, Maria O.; Akkuzina, Alina A.; Saifutyarov, Rasim R.; Ermolaeva, Ekaterina V.; Avetisov, Roman I.; Khomyakov, Andrew V.; Taydakov, Ilya V.; Avetissov, Igor Ch.

2017-07-01

Novel luminescent organic-inorganic hybrid materials based on 8-hydroxyquinoline metal complexes (Liq, Kq, Naq, Rbq, Mgq2, Srq2, Znq2, Scq3, Alq3, Gaq3, and Inq3) have been synthesized by a high temperature exchange reaction with 80PbF2-20B2O3 inorganic low-melting glass. The mechanical and optical properties, transmission spectra, emission an excitation photoluminescence, and luminescence kinetic of hybrid materials were studied. All hybrid materials showed a wide luminescence band in the range 400-700 nm.

Biosynthesis of myristic acid in luminescent bacteria

International Nuclear Information System (INIS)

Byers, D.M.

1987-01-01

In vivo pulse-label studies have demonstrated that luminescent bacteria can provide myritic acid (14:0) required for the synthesis of the luciferase substrate myristyl aldehyde. Luminescent wild type Vibrio harveyi incubated with [ 14 C] acetate in a nutrient-depleted medium accumulated substantial tree [ 14 C]fatty acid (up to 20% of the total lipid label). Radio-gas chromatography revealed that > 75% of the labeled fatty acid is 14:0. No free fatty acid was detected in wild type cells labeled prior to the development of bioluminescence in the exponential growth phase, or in a dark mutant of V. harveyi (mutant M17) that requires exogenous 14:0 for light emission. The preferential accumulation of 14:0 was not observed when wild type cells were labeled with [ 14 C]acetate in regular growth medium. Moreover, all V. harveyi strains exhibited similar fatty acid mass compositions regardless of the state of bioluminescence. Since earlier work has shown that a luminescence-related acyltransferase (defective in the M17 mutant) can catalyze the deacylation of fatty acyl-acyl carrier protein in vitro, the present results are consistent with a model in which this enzyme diverts 14:0 to the luminescence system during fatty acid biosynthesis. Under normal conditions, the supply of 14:0 by this pathway is tightly regulated such that bioluminescence development does not significantly alter the total fatty acid composition

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.

Luminescence investigations of rare earth doped lead-free borate glasses modified by MO (M = Ca, Sr, Ba)

Energy Technology Data Exchange (ETDEWEB)

Janek, Joanna, E-mail: janek.joanna@gmail.com; Sołtys, Marta; Żur, Lidia; Pietrasik, Ewa; Pisarska, Joanna; Pisarski, Wojciech A.

2016-09-01

Series of lead-free borate glasses with different oxide modifiers and lanthanide ions were prepared. The effect of oxide modifiers MO (M = Ca, Sr, Ba) on spectroscopic properties of trivalent Ln{sup 3+} (Ln = Eu, Er, Pr) were systematically investigated. Especially, the luminescence spectra of Ln{sup 3+}-doped lead-free borate glasses are presented and discussed in relation to the impact of selective components (CaO, SrO and BaO). Several spectroscopic parameters, such as the fluorescence intensity ratio R/O (Eu{sup 3+}) and measured luminescence lifetimes for the {sup 5}D{sub 0} (Eu{sup 3+}), {sup 4}I{sub 13/2} (Er{sup 3+}) and {sup 1}D{sub 2} (Pr{sup 3+}) excited states of lanthanide ions were analyzed in details. The research proved that spectroscopic properties of trivalent Ln{sup 3+} depend significantly on kind of presence oxide modifiers MO (M = Ca, Sr, Ba) in glass host matrices. - Highlights: • Luminescence of Ln{sup 3+}-doped borate glasses was presented and discussed. • Effect of glass modifiers on spectroscopic properties of rare earths was studied. • Measured luminescence lifetimes of Ln{sup 3+} (Ln = Eu, Er, Pr) were analyzed. • Luminescence intensity ratios R/O (Eu{sup 3+}) were determined.

Synthesis and luminescent properties of Sr{sub 2}Gd{sub 6.8}Eu{sub 1.2}Si{sub 6(1−x)}P{sub 6x}O{sub 26} oxyapatites

Energy Technology Data Exchange (ETDEWEB)

Ishchenko, A.V., E-mail: a-v-i@mail.ru [Ural Federal University, 620002 Ekaterinburg (Russian Federation); Zuev, M.G. [Ural Federal University, 620002 Ekaterinburg (Russian Federation); Institute of Solid State Chemistry, Ural Branch of the Russian Academy of Sciences, 620990 Ekaterinburg (Russian Federation); Vasin, A.A. [Institute of Solid State Chemistry, Ural Branch of the Russian Academy of Sciences, 620990 Ekaterinburg (Russian Federation); Yagodin, V.V.; Viktorov, L.V.; Shulgin, B.V. [Ural Federal University, 620002 Ekaterinburg (Russian Federation)

2016-01-15

The solid solutions Sr{sub 2}Gd{sub 6.8}Eu{sub 1.2}Si{sub 6(1−x)}P{sub 6x}O{sub 26−δ} (where x=0–0.15 and δ is oxygen nonstoichiometry) were synthesized. The structural properties of the crystal lattice of the solid solutions and the peculiarities of Eu{sup 3+} and P{sup 5+} dopants substitution for matrix ions have been considered. The photo-, X-ray and pulsed cathode luminescence properties have been studied. It has been found that substitution of (SiO{sub 4}){sup 4−} by (PO{sub 4}){sup 3−} tetrahedron in Eu{sup 3+}-doped oxyapatites does not bring significant changes to bands structure Eu{sup 3+} in luminescence spectra under different excitation (UV, X-ray, pulse cathode beam). However, the increase of P{sup 5+} concentration in Sr{sub 2}Gd{sub 6.8}Eu{sub 1.2}Si{sub 6(1−x)}P{sub 6x}O{sub 26–δ} compounds leads to a decrease of integral intensity of Eu{sup 3+} luminescence bands due to local environment symmetry modifications and covalency degree changes. Two nonequivalent optical Eu{sup 3+} centers have been found. These compounds are of interest for efficient X-ray phosphors, display devices and LED engineering material creation. - Highlights: • The luminescence properties were studied upon UV, X-ray and pulse cathode beam. • P{sup 5+} doping of Sr{sub 2}Gd{sub 6.8}Eu{sub 1.2}Si{sub 6}O{sub 26} leads to luminescence intensity reduction. • At least two types of optical centers formed by Eu{sup 3+} ions were found. • The structural features of Sr{sub 2}Gd{sub 6.8}Eu{sub 1.2}Si{sub 6(1−x)}P{sub 6x}O{sub 26} were reported. • Partial replacement of Si by P does not change the Sr{sub 2}Gd{sub 6.8}Eu{sub 1.2}Si{sub 6}O{sub 26} structure.

Effect of particle size and morphology on the properties of luminescence in ZnWO4

International Nuclear Information System (INIS)

Lisitsyn, V.M.; Valiev, D.T.; Tupitsyna, I.A.; Polisadova, E.F.; Oleshko, V.I.; Lisitsyna, L.A.; Andryuschenko, L.A.; Yakubovskaya, A.G.; Vovk, O.M.

2014-01-01

We investigated pulsed photoluminescence and pulsed cathodoluminescence in ZnWO 4 crystals and composite materials based on dispersed powders of zinc tungstate in the polymer matrix. It is shown that the size of crystal particles affects the luminescence decay time in excitation by electron and laser radiation. The decay time obtained for the composite material with nanoparticles 25 nm and 100 nm in size is equal to 5 µs and 7 µs, respectively. Relative values of the light yield of composite containing zinc tungstate crystals in the form of rods are found to be larger in comparison with crystallites in the form of grains. The mechanisms of luminescence recombination in laser and electron excitation are discussed. - Highlights: • Pulsed photoluminescence and pulsed cathodoluminescence spectra and decay kinetics of nano- and microcrystals of zinc tungstate in the organosilicic matrix compared to a single crystal were studied. • The luminescence decay kinetics and life-time of the excited state depend on the size of particles in the composite materials and on the type of excitation. • The probability of excitation of luminescence centers responsible for the band at 490 nm is higher which is apparently due to the larger capture cross-section and quantum yield

On optically stimulated luminescence properties of household salt as a retrospective dosemeter

International Nuclear Information System (INIS)

Timar-Gabor, A.; Trandafir, O.

2013-01-01

Thermoluminescence (TL) and optically stimulated luminescence (OSL) in the UV (270-370 nm) spectral region have been investigated for five types of table salt (NaCl) available in Romanian supermarkets with a view to applying them in retrospective dosimetry. The salt samples gave bright TL signals with two main peaks at ∼ 100 deg. C and at 300 or 260 deg. C, depending on the origin of the salt and bright OSL signals under continuous stimulation with blue light. The OSL signal (stimulated at 100 deg. C after a pre-heat of 10 s at 150 deg. C) was used for investigations in a standard multiple aliquot procedure. The dose- response was found to be linear in the dose range investigated (up to ∼ 100 mGy) and the lower limit of detection for the samples varied from ∼ 0.01 to 14 mGy. These characteristics, along with the widespread abundance and low cost of household salt, confirm its potential as a retrospective dosemeter. (authors)

Optically stimulated luminescence dosimetry using natural and synthetic materials

DEFF Research Database (Denmark)

Bøtter-Jensen, L.; McKeever, S.W.S.

1996-01-01

The application of optically stimulated luminescence (OSL) for use in radiation dosimetry is reviewed. A broad description is given of OSL techniques developed at Riso National Laboratory and at Oklahoma State University, and recent collaborative investigations on the properties of a variety...

Luminescence from metals and insulators

International Nuclear Information System (INIS)

Crawford, O.H.

1985-01-01

The term luminescence is normally applied to light emission that is not explainable by the mechanisms discussed by the other speakers in this meeting. Specifically, it is not transition radiation, surface plasmon radiation, or bremsstrahlung. One normally thinks of luminescence as arising from one-electron transitions within a medium. This talk consists of an overview of luminescence from condensed matter under irradiation by either energetic particles or photons. The author begins with organic molecules, where luminescence is best understood, and then discusses inorganic insulators and metals. Finally, the dependence of yield upon projectile species and velocity is discussed, and predictions are made concerning the relative effectiveness of electrons, protons, and hydrogen atoms in exciting luminescence

Low temperature luminescence and charge carrier trapping in a cryogenic scintillator Li{sub 2}MoO{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Spassky, D.A., E-mail: deris2002@mail.ru [Institute of Physics, University of Tartu, Ravila 14c, 50411 Tartu (Estonia); Skobeltsyn Institute of Nuclear Physics, Moscow State University, 119991 Moscow (Russian Federation); Nagirnyi, V. [Institute of Physics, University of Tartu, Ravila 14c, 50411 Tartu (Estonia); Savon, A.E. [Skobeltsyn Institute of Nuclear Physics, Moscow State University, 119991 Moscow (Russian Federation); Kamenskikh, I.A. [Physics Faculty, Moscow State University, 119991 Moscow (Russian Federation); Barinova, O.P.; Kirsanova, S.V. [D. Mendeleyev University of Chemical Technology of Russia, 125047 Moscow (Russian Federation); Grigorieva, V.D.; Ivannikova, N.V.; Shlegel, V.N. [Nikolaev Institute of Inorganic Chemistry, SB RAS, 630090 Novosibirsk (Russian Federation); Aleksanyan, E. [Institute of Physics, University of Tartu, Ravila 14c, 50411 Tartu (Estonia); A.Alikhanyan National Science Laboratory, 2 Br. Alikhanyan Str., 0036 Yerevan (Armenia); Yelisseyev, A.P. [Sobolev Institute of Geology and Mineralogy, SB RAS, 630090 Novosibirsk (Russian Federation); Belsky, A. [Institute of Light and Matter, CNRS, University Lyon1, 69622 Villeurbanne (France)

2015-10-15

The luminescence and optical properties of promising cryogenic scintillator Li{sub 2}MoO{sub 4} were studied in the temperature region of 2–300 K. The data on luminescence spectra and decay characteristics, excitation spectra, thermostimulated luminescence curves and spectra as well as transmission and reflectivity spectra are presented for the single crystals grown by two different procedures, the conventional Czochralski method and the low-temperature gradient Czochralski technique. The bandgap of Li{sub 2}MoO{sub 4} is estimated from the analysis of transmission, luminescence excitation and reflectivity spectra. Up to three luminescence bands with the maxima at 1.98, 2.08 and 2.25 eV are detected in the emission spectra of crystals and their origin is discussed. In the thermoluminescence curves of both studied crystals, two high-intensity peaks were observed at 22 and 42 K, which are ascribed to the thermal release of self-trapped charge carriers. The coexistence of self-trapped electrons and holes allows one to explain the poor scintillation light yield of Li{sub 2}MoO{sub 4} at low temperatures. - Highlights: • Single crystals of Li{sub 2}MoO{sub 4} were grown by two methods. • The transparency cutoff (~4.3 eV) and bandgap values (<4.9 eV) are estimated. • The emission 2.08 eV is ascribed to self-trapped excitons and quenches at T>7 K. • Shallow traps considerably influence the energy transfer to emission centres. • Co-existence of self-trapped holes and electrons results in a low light yield.

Efficient and thermally stable red luminescence from nano-sized phosphor of Gd6MoO12:Eu3+

International Nuclear Information System (INIS)

Qin, Lin; Wei, Donglei; Huang, Yanlin; Kim, Sun Il; Yu, Young Moon; Seo, Hyo Jin

2013-01-01

A novel red-emitting nano-phosphor of Eu 3+ -doped Gd 6 MoO 12 was successfully synthesized by the Pechini method. The crystalline phase was confirmed by X-ray powder diffraction analysis. The morphology of the nano-phosphor was analyzed by scanning electron microscopy, indicating a good crystallization with particles smaller than 500 nm. The luminescence properties such as photoluminescence spectra and decay curves were investigated. The phosphors can be efficiently excited by near-ultraviolet (near-UV) light and exhibit a bright red luminescence around 613 nm ascribed to the forced electric dipole transition 5 D 0 → 7 F 2 of Eu 3+ ions. The thermal stabilities were investigated from the temperature-dependent luminescence decay curves (lifetimes) and spectra intensities. The luminescence properties in relation to applications in white light-emitting diodes (W-LEDs) such as the absolute luminescence quantum efficiency, excitation wavelength, and color coordinates were discussed. The Gd 6 MoO 12 :Eu 3+ nano-phosphor is a promising red-emitting candidate for the fabrication of W-LEDs with near-UV chips

Emission properties of polymer composites doped with Er3+:Y2O3 nanopowders

Science.gov (United States)

Anders, Krzysztof; Jusza, Anna; Baran, Magdalena; Lipińska, Ludwika; Piramidowicz, Ryszard

2012-10-01

In this work we report the recent results of our investigation on visible emission properties of the PMMA-based polymer nanocomposites doped with Er3+:Y2O3 nanopowders. The set of active nanopowders, and polymer films, differing in active ions concentration, was characterized with respect of their luminescent properties in the green spectral range, available to a limited extent for semiconductor lasers. In particular - the concentration dependent emission spectra and fluorescence dynamics profiles were measured under direct (single photon) and up-converted excitation, enabling the comparison of luminescent properties of developed nanocomposite materials and original nanopowders, optimization of erbium dopant concentration as well as discussion of excitation mechanisms and analysis of the efficiency of depopulation processes.

Structural and luminescence properties of Mn2+ ions doped calcium zinc borophosphate glasses

International Nuclear Information System (INIS)

Wan, Ming Hua; Wong, Poh Sum; Hussin, Rosli; Lintang, Hendrik O.; Endud, Salasiah

2014-01-01

Highlights: • FT-IR revealed that the network structures are from borate and phosphate network. • The PL spectrum exhibits a green emission band at 582 nm ( 4 T 1g → 6 A 1g ). • As the concentration of Mn 2+ ions is increased, the emission band had been red shifted. • These glasses are found to have potential applications as luminescent optical materials. - Abstract: Calcium zinc borophosphate glasses (CaZnBP) doped with various concentrations of Mn 2+ ions and borate and phosphate as variable were prepared using conventional melt quenching technique. The structure of obtained glasses were examined by means of use: X-ray diffraction (XRD) and fourier transform infrared (FT-IR). XRD analysis confirmed amorphous nature of glass samples. The FT-IR spectra reveals the presence of both borate and phosphate vibrational modes in the prepared glasses. The doping of Mn 2+ ions (2–10 mol%) shows no significant changes in the main IR vibrational bands. Optical properties were studied by measuring the near infrared photoluminescence (PL) spectra. CaZnBP glasses exhibited intense green emission peak (582 nm) (tetrahedral symmetry), which is assigned to a transition from the upper 4 T 1g → 6 A 1g ground state of Mn 2+ ions. As the concentration of Mn 2+ ions increases, the emission band increases from 582 nm to 650 nm and exhibited a red light emission (octahedral symmetry). The decay curves of 4 T 1g level were examined for all concentrations and the measured lifetimes are found to depend strongly on Mn 2+ concentrations. From the emission characteristic parameters of 6 A 1g (S) level, it shows that the CaZnBP glasses could have potential applications as luminescent optical materials, visible lasers and fluorescent display devices

The double luminescence of Color Centers

International Nuclear Information System (INIS)

Baldacchini, Giuseppe

2015-01-01

An experiment on the luminescence of Color Centers (CCs) carried out in 1987 at the ENEA Laboratories in Frascati had a negative result, but subsequent investigations showed that it was not a failure but rather a discovery of a new phenomenon. Since the coming of lasers, CCs in alkali halides have been successfully used as optically active materials, in particular FA Centers. One of these centers, well known for its medium infrared laser emission at 77 K, cooled further to 2 K emitted in the near infrared and without laser effect. Further investigations showed that the double luminescence was a fundamental property unknown until that time. This important discovery was achieved in Frascati because of the existence since 1973 of a solid and extensive expertise in the field of CCs, which continued over time and later on applied to the modern miniaturized photonic devices [it

Luminescence properties of In(Zn)P alloy core/ZnS shell quantum dots

Science.gov (United States)

Thuy, Ung Thi Dieu; Reiss, Peter; Liem, Nguyen Quang

2010-11-01

Chemically synthesized InP/ZnS core/shell quantum dots (QDs) are studied using time-resolved photoluminescence spectroscopy and x-ray diffraction. Zinc stearate, which is added during the synthesis of the InP core, significantly improves the optical characteristics of the QDs. The luminescence quantum yield (QY) reaches 60%-70% and the emission is tunable from 485 to 586 nm by varying the Zn2+:In3+ molar ratio and growth temperature. The observed increased Stokes shift, luminescence decay time, and QY in the presence of Zn are rationalized by the formation of an In(Zn)P alloy structure that causes band-edge fluctuation to enhance the confinement of the excited carriers.

Up-conversion and near infrared luminescence in Er3+/Yb3+ co-doped glass-ceramic containing MgGa2O4 nano-crystals

International Nuclear Information System (INIS)

Sun, Jiaju; Yu, Lixin; Li, Fuhai; Wei, Shuilin; Li, Songchu

2016-01-01

The MgO–Ga 2 O 3 –SiO 2 (MG-S) glasses and nanocrystalline glass-ceramics (GCs) containing MgGa 2 O 4 nanocrystals codoped with Er 3+ and Yb 3+ were prepared by a simple sol–gel method. The formation of MgGa 2 O 4 nanocrystals in the GCs was confirmed by the X-ray diffraction (XRD). Their morphology was investigated applying high-resolution transmission electron microscopy (HRTEM). Stark splitting of near infrared (NIR) and up-conversion (UC) emission implies that the Er 3+ is incorporated into MgGa 2 O 4 nanocrystals. The effect of the MgO, Ga 2 O 3 content and sintering temperature on the structure of the prepared samples was systematically studied. Under 980 nm excitation, intense UC and NIR emission (1530 nm) were observed in the MG-S GCs by efficient energy transfer from Yb 3+ to Er 3+ . The two-photon process was confirmed to be responsible for both the green and red UC emissions. - Highlights: • It is interesting that the CIE chromaticity coordinates of the several prepared CaMO 4 :Eu samples by a hydrothermal method are very close to the standard of white light.

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

Synthesis and luminescence properties of KSrPO{sub 4}:Eu{sup 2+} phosphor for radiation dosimetry

Energy Technology Data Exchange (ETDEWEB)

Palan, C. B., E-mail: chetanpalan27@yahoo.in [Department of Physics, Sant Gadge Baba Amravati University, Amravati-444602 (India); Bajaj, N. S. [Toshniwal ACS College, Sengaon, Hingoli-431542 (India); Omanwar, S. K.

2016-05-06

The KSrPO{sub 4}:Eu phosphor was synthesized via solid state method. The structural and morphological characterizations were done through XRD (X-ray diffraction) and SEM (Scanning Electronic Microscope). Additionally, the photoluminescence (PL), thermoluminescence (TL) and optically Stimulated luminescence (OSL) properties of powder KSrPO{sub 4}:Eu were studied. The PL spectra show blue emission under near UV excitation. It was advocated that KSrPO{sub 4}:Eu phosphor not only show OSL sensitivity (0.47 times) but also gives faster decay in OSL signals than that of Al{sub 2}O{sub 3}:C (BARC) phosphor. The TL glow curve consist of two shoulder peaks and the kinetics parameters such as activation energy and frequency factors were determined by using peak shape method and also photoionization cross-sections of prepared phosphor was calculated. The radiation dosimetry properties such as minimum detectable dose (MDD), dose response and reusability were reported.

Ion beam induced luminescence from diamond using an MeV ion microprobe

Energy Technology Data Exchange (ETDEWEB)

Bettiol, A.A.; Jamieson, D. N.; Prawer, S.; Allen, M.G. [Melbourne Univ., Parkville, VIC (Australia). School of Physics

1993-12-31

Analysis of the luminescence induced by a MeV ion beam offers the potential to provide useful information about the chemical properties of atoms in crystals to complement the information provided by more traditional Ion Beam Analysis (IBA) such as Rutherford Backscattering Spectrometry (RBS), ion channeling and Particle Induced X-ray Emission (PIXE). Furthermore, the large penetration depth of the MeV ion beam offers several advantages over the relatively shallow penetration of keV electrons typically employed in cathodoluminescence. An Ion Beam Induced Luminescence (IBIL) detection system was developed for the Melbourne microprobe that allows the spatial mapping of the luminescence signal along with the signals from RBS and PIXE. Homoepitaxial diamond growth has been studied and remarkable shifts in the characteristic blue luminescence of diamond towards the green were observed in the overgrowth. This has been tentatively identified as being due to transition metal inclusions in the epitaxial layers. 8 refs., 2 refs.

Ion beam induced luminescence from diamond using an MeV ion microprobe

Energy Technology Data Exchange (ETDEWEB)

Bettiol, A A; Jamieson, D N; Prawer, S; Allen, M G [Melbourne Univ., Parkville, VIC (Australia). School of Physics

1994-12-31

Analysis of the luminescence induced by a MeV ion beam offers the potential to provide useful information about the chemical properties of atoms in crystals to complement the information provided by more traditional Ion Beam Analysis (IBA) such as Rutherford Backscattering Spectrometry (RBS), ion channeling and Particle Induced X-ray Emission (PIXE). Furthermore, the large penetration depth of the MeV ion beam offers several advantages over the relatively shallow penetration of keV electrons typically employed in cathodoluminescence. An Ion Beam Induced Luminescence (IBIL) detection system was developed for the Melbourne microprobe that allows the spatial mapping of the luminescence signal along with the signals from RBS and PIXE. Homoepitaxial diamond growth has been studied and remarkable shifts in the characteristic blue luminescence of diamond towards the green were observed in the overgrowth. This has been tentatively identified as being due to transition metal inclusions in the epitaxial layers. 8 refs., 2 refs.

Optical stimulated luminescence (OSL) dating

International Nuclear Information System (INIS)

Banerjee, D.

1999-01-01

Since the pioneering work by Huntley et al. (1985), optical dating is being increasingly recognised as an important technique for establishing a time frame of deposition of sediments (Aitken, 1998). Optical dating differs from thermoluminescence (TL) dating in that visible/infrared light from lasers or LEDs (light-emitting-diodes) is used as a means of stimulation, in contrast to thermal stimulation. It has several advantages over TL dating: (i) the resetting of the OSL (optically stimulated luminescence) clock is more effective than that of TL clock; for sediments transported under water or in other situations where the sediment grains have undergone inhomogeneous bleaching, this property ensures that ages based on optical dating are generally more reliable than TL ages, (ii) the optical dating technique is non-destructive, and multiple readouts of the optical signal is possible; this feature has resulted in the development of single-aliquot and single-grain protocols (Murray and Wintle, 1999; Banerjee et al. 1999), (iii) the sample is not heated as in TL; thus, spurious luminescence is avoided and there is a significant reduction in blackbody radiation. Dating of materials which change phase on heating is also practical, and finally, (iv) thermal quenching of luminescence is negligible, allowing accurate estimation of kinetic parameters using standard techniques and providing access to deep OSL traps. This characteristic may be helpful in extending the limits of optical dating beyond the last 150 ka from a global point of view

Resonance-shifting luminescent solar concentrators

Energy Technology Data Exchange (ETDEWEB)

Giebink, Noel Christopher; Wiederrecht, Gary P.; Wasielewski, Michael R.

2018-01-23

An optical system and method to overcome luminescent solar concentrator inefficiencies by resonance-shifting, in which sharply directed emission from a bi-layer cavity into a glass substrate returns to interact with the cavity off-resonance at each subsequent reflection, significantly reducing reabsorption loss en route to the edges. In one embodiment, the system comprises a luminescent solar concentrator comprising a transparent substrate, a luminescent film having a variable thickness; and a low refractive index layer disposed between the transparent substrate and the luminescent film.

Sub-Band Gap Turn-On Near-Infrared-to-Visible Up-Conversion Device Enabled by an Organic-Inorganic Hybrid Perovskite Photovoltaic Absorber.

Science.gov (United States)

Yu, By Hyeonggeun; Cheng, Yuanhang; Li, Menglin; Tsang, Sai-Wing; So, Franky

2018-05-09

Direct integration of an infrared (IR) photodetector with an organic light-emitting diode (OLED) enables low-cost, pixel-free IR imaging. However, the operation voltage of the resulting IR-to-visible up-conversion is large because of the series device architecture. Here, we report a low-voltage near-IR (NIR)-to-visible up-conversion device using formamidinium lead iodide as a NIR absorber integrated with a phosphorescent OLED. Because of the efficient photocarrier injection from the hybrid perovskite layer to the OLED, we observed a sub-band gap turn-on of the OLED under NIR illumination. The device showed a NIR-to-visible up-conversion efficiency of 3% and a luminance on/off ratio of 10 3 at only 5 V. Finally, we demonstrate pixel-free NIR imaging using the up-conversion device.

The influence of Ag content and annealing time on structural and optical properties of SGS antimony-germanate glass doped with Er3+ ions

Science.gov (United States)

Zmojda, J.; Kochanowicz, M.; Miluski, P.; Baranowska, A.; Basa, A.; Jadach, R.; Sitarz, M.; Dorosz, D.

2018-05-01

A series of erbium doped SGS antimony-germanate glass embedding silver (Ag0) nanoparticles have been synthesized by a one-step melt-quench thermochemical reduction technique. The effect of NPs concentration and annealing time on the structural and photoluminescent (PL) properties were investigated. The Raman spectra as a function of temperature measured in-situ allow to determine the structural changes in vicinity of Ag+ ions and confirmed thermochemical reduction of Ag+ ions by Sb3+ ions. The surface plasmon resonance absorption band was evidenced near 450 nm. The impact of local field effect generated by Ag0 nanoparticles (NPs) and energy transfer from surface of silver NPs to trivalent erbium ions on near-infrared and up-conversion luminescence was described in terms of enhancement and quench phenomena.

Optically stimulated luminescence dosimetry performance of natural Brazilian topaz exposed to beta radiation

International Nuclear Information System (INIS)

Bernal, R.; Souza, D. N.; Valerio, M. E. G.; Cruz-Vazquez, C.; Barboza-Flores, M.

2006-01-01

Optically stimulated luminescence (OSL) has become the technique of choice in many areas of dosimetry. Natural materials like topaz are available in large quantities in Brazil and other countries. They have been studied to investigate the possibility of use its thermoluminescence (TL) properties for dosimetric applications. In this work, we investigate the possibility of utilising the OSL properties of natural Brazilian topaz in dosimetry. Bulk topaz samples were exposed to doses up to 100 Gy of beta radiation and the integrated OSL as a function of the dose showed linear behaviour. The fading occurs in the first 20 min after irradiation but it is <6% of the integrated OSL measured shortly after exposure. We conclude that natural colourless topaz is a very suitable phosphor for OSL dosimetry. (authors)

Luminescent Eosin Y–SiO{sub 2} hybrid nano and microrods prepared by sol–gel template method

Energy Technology Data Exchange (ETDEWEB)

Secu, M., E-mail: msecu@infim.ro [National Institute for Materials Physics, P.O. Box MG-7, Bucharest–Magurele, 077125 (Romania); Secu, C.E.; Sima, M.; Negrea, R.F.; Bartha, C. [National Institute for Materials Physics, P.O. Box MG-7, Bucharest–Magurele, 077125 (Romania); Dinescu, M.; Damian, V. [National Institute for Laser, Plasma and Radiation, P.O. Box MG-36, Bucharest–Magurele 077125 (Romania)

2013-11-15

Sol–gel chemistry within the pores of a polycarbonate template membrane was used for the preparation of Eosin Y–SiO{sub 2} hybrid nano- and microrods, using tetraethylorthosilicate [TEOS, Si(OC{sub 2}H{sub 5}){sub 4}] as the precursor in the presence of trifluoroacetic acid (TFA) catalyst. The ethanolic solution of Eosin-Y was added to the silica sol to trap dye molecules inside the SiO{sub 2} gel network during the gelation. Structural and morphological characterization using scanning electron microscopy (SEM) and luminescence microscopy have shown the formation of rods with 200 nm and 1.2 μm diameter and about 30 μm length, exhibiting luminescence properties. Spectroscopic characterization has shown that the luminescence is due to Eosin-Y molecule in the xerogel porous network, surrounded by a solvation shell given mainly by the water. -- Highlights: • Sol–gel template method was used to prepare Eosin Y–SiO{sub 2} hybrid rods-type structures. • Morphological characterization has shown nano- and microrods with luminescent properties. • Luminescence is due to Eosin-Y molecule surrounded by a solvation shell given by water.

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....

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.

Luminescence and surface properties of Tb3+ doped Sr3(VO4)2 nanophosphors

International Nuclear Information System (INIS)

Bedyal, A.K.; Kumar, Vinay; Sharma, Vishal

2013-01-01

In this paper, we present a detailed investigation of the luminescence and surface properties of Tb 3+ doped Sr 3 (VO 4 ) 2 nanocrystalline phosphors, synthesized by the combustion method. X-ray diffraction (XRD) peaks in the patterns corresponding to the reflection of rhombohedral pure phase of Sr 3 (VO 4 ) 2 . The average particle sizes have been found in the range of 30-34 nm. Scanning electron microscopy (SEM) indicated that an agglomerated peanut like morphology was obtained. Photoluminescence (PL) spectroscopy has been utilized to investigate the spectral properties of the phosphor. Under 237 nm excitation, it shows several bands centered at 487, 544, 588 and 624 nm, which result from 5 D 4 → 7 F J (J = 6, 5, 4 and 3) transitions of Tb 3+ , and the green emission band ( 5 D 4 → 7 F 5 ) located at 544 nm is dominant. The chemical states and homogeneous dopants' distribution in the host were analyzed with X-ray photoelectron spectroscopy (XPS) and time of flight-secondary ion mass spectroscopy (TOF-SIMS), respectively. A ToF-SIMS imaging shows an uniform distribution of Tb 3+ in the Sr 3 (VO 4 ) 2 . (author)

Novel Luminescent Probe Based on a Terbium(III) Complex for Hemoglobin Determination

Science.gov (United States)

Yegorova, A. V.; Leonenko, I. I.; Aleksandrova, D. I.; Scrypynets, Yu. V.; Antonovich, V. P.; Ukrainets, I. V.

2014-09-01

We have studied the spectral luminescent properties of Tb(III) and Eu(III) complexes with a number of novel derivatives of oxoquinoline-3-carboxylic acid amides (L1-L5 ). We have observed quenching of the luminescence of 1:1 Tb(III)-L1-5 complexes by hemoglobin (Hb), which is explained by resonance energy transfer of electronic excitation from the donor (Tb(III)-L1-5 ) to the acceptor (Hb). Using the novel luminescent probe Tb(III)-L1, we have developed a method for determining Hb in human blood. The calibration Stern-Volmer plot is linear in the Hb concentration range 0.6-36.0 μg/mL, detection limit 0.2 μg/mL (3·10-9 mol/L).

The First Organic-Inorganic Hybrid Luminescent Multiferroic: (Pyrrolidinium)MnBr3.

Science.gov (United States)

Zhang, Yi; Liao, Wei-Qiang; Fu, Da-Wei; Ye, Heng-Yun; Liu, Cai-Ming; Chen, Zhong-Ning; Xiong, Ren-Gen

2015-07-08

A hybrid organic-inorganic compound, (pyrrolidinium)MnBr3 , distinguished from rare earth (RE)-doped inorganic perovskites, is discovered as a new member of the ferroelectrics family, having excellent luminescent properties and relatively large spontaneous polarization of 6 μC cm(-2) , as well as a weak ferromagnetism at about 2.4 K. With a quantum yield of >28% and emission lifetime >0.1 ms, such multiferroic photoluminescence is a suitable candidate for future applications in luminescence materials, photovoltaics, and magneto-optoelectronic devices. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Hydrothermal synthesis and luminescent properties of LnPO4:Tb,Bi (Ln=La,Gd) phosphors under UV/VUV excitation

International Nuclear Information System (INIS)

Wang Yuhua; Wu Chunfang; Wei Jie

2007-01-01

Monoclinic LnPO 4 :Tb,Bi (Ln=La,Gd) phosphors were prepared by hydrothermal reaction and their luminescent properties under ultraviolet (UV) and vacuum ultraviolet (VUV) excitation were investigated. LaPO 4 :Tb,Bi phosphor and GdPO 4 :Tb phosphor showed the strongest emission intensity under 254 and 147 nm excitation, respectively, because of the different energy transfer models. In UV region, Bi 3+ absorbed most energy then transferred to Tb 3+ , but in VUV region it was the host which absorbed most energy and transferred to Tb 3+

Optically stimulated luminescence in electronic components for emergency dosimetry

International Nuclear Information System (INIS)

Geber-Bergstrand, T.; Bernhardsson, C.; Mattsson, S.; Raeaef, C.L.

2015-01-01

Document available in abstract form only. Full text of publication follows: Accidents and, luckily more rarely, attacks involving nuclear or radiological material do occur from time to time. A very possible consequence of an accident or attack of this kind is that nearby people might be exposed to ionising radiation. Since these types of exposure situations, unlike the ones occurring in medicine, are unplanned, there are no radiation-monitoring data available. For several reasons, it is nevertheless of value to find out the dose that these people have received. The first and most urgent reason is after-the-event triage, to be able to carry out proper medical treatments and also to focus the available medical assets to the persons needing it the most. This is where different retrospective dosimetry techniques, such as luminescence, can be employed. Various electronic components from mobile phones and other portable devices have been studied using optically stimulated luminescence for their potential use in retrospective dosimetry. Previous investigations have been performed in laboratory conditions and have showed very promising properties for emergency dosimetry. In this study, the more practical parts of using electronic components in retrospective dosimetry have been considered. In a triage situation, one of the key parameters to consider is time; thus, effort has been made to speed up the readout procedure, yet without the loss of too much accuracy. (authors)

The origin of luminescence from di[4-(4-diphenylaminophenyl)phenyl]sulfone (DAPSF), a blue light emitter: an X-ray excited optical luminescence (XEOL) and X-ray absorption near edge structure (XANES) study.

Science.gov (United States)

Zhang, Duo; Zhang, Hui; Zhang, Xiaohong; Sham, Tsun-Kong; Hu, Yongfeng; Sun, Xuhui

2016-03-07

The electronic structure and optical properties of di[4-(4-diphenylaminophenyl)phenyl]sulfone (denoted as DAPSF), a highly efficient fluorophor, have been investigated using X-ray excited optical luminescence (XEOL) and X-ray absorption near edge structure (XANES) spectroscopy at excitation energies across the C, N, O K-edges and the sulfur K-edge. The results indicate that the blue luminescence is mainly related to the sulfur functional group.

Electrons in feldspar II: A consideration of the influence of conduction band-tail states on luminescence processes

DEFF Research Database (Denmark)

Poolton, H.R.J.; Ozanyan, K.B.; Wallinga, J.

2002-01-01

consider what influence the band tails have on the luminescence properties of feldspar, where electrons travel through the sample prior to recombination. The work highlights the dominant role that 0.04-0.05-eV phonons play in both the luminescence excitation and emission processes of these materials...

Time-resolved measurements of luminescence

Energy Technology Data Exchange (ETDEWEB)

Collier, Bradley B. [Department of Biomedical Engineering, 408 Mechanical Engineering Office Building, Spence Street, Texas A and M University, College Station, TX 77843 (United States); McShane, Michael J., E-mail: mcshane@tamu.edu [Department of Biomedical Engineering, 408 Mechanical Engineering Office Building, Spence Street, Texas A and M University, College Station, TX 77843 (United States); Materials Science and Engineering Program, 408 Mechanical Engineering Office Building, Spence Street, Texas A and M University, College Station, TX 77843 (United States)

2013-12-15

Luminescence sensing and imaging has become more widespread in recent years in a variety of industries including the biomedical and environmental fields. Measurements of luminescence lifetime hold inherent advantages over intensity-based response measurements, and advances in both technology and methods have enabled their use in a broader spectrum of applications including real-time medical diagnostics. This review will focus on recent advances in analytical methods, particularly calculation techniques, including time- and frequency-domain lifetime approaches as well as other time-resolved measurements of luminescence. -- Highlights: • Developments in technology have led to widespread use of luminescence lifetime. • Growing interest for sensing and imaging applications. • Recent advances in approaches to lifetime calculations are reviewed. • Advantages and disadvantages of various methods are weighed. • Other methods for measurement of luminescence lifetime also described.

Time-resolved measurements of luminescence