CLAUDIA AKEMI KODAIRA GOES

CLAUDIA AKEMI KODAIRA GOES

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Persistent luminescence BaAlsub(2)Osub(4):Eusup(2+), Dysup(3+) phosphor incorporated in silica: water resistance
2009 - LOURENCO, A.V.S.; RODRIGUES, L.C.V.; KODAIRA, C.A.; STEFANI, R.; BRITO, H.F.; FELINTO, M.C.F.C.; HOLSA, J.
Barium aluminates doped with divalent europium and trivalent dysprosium were prepared with the combustion method and then incorporated with silica using the microemulsion method. The incorporated phosphor particles showed improved water resistance, preserving much of the prior persistent luminescence properties even after interaction with water whereas the nonincorporated particles loosed the original persistent luminescence. The infrared absorption spectroscopy, X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence studies were used to characterize the phosphors. The pH of the phosphor-water mixture after the reaction with water was measured to compare the water resistance of the materials. The photoluminescence of the incorporated BaAl2O4:Eu2+,Dy3+ with water modified slightly the 4f6 5d1 →4f7 transition of Eu2+, however.
Long lasting phosphorescence of Eusup(2+) and Dysup(3+) ions doped in barium aluminate
2007 - STEFANI, ROBERVAL; RODRIGUES, LUCAS C.V.; CARVALHO, CARLOS A.A.; BRITO, HERMI F.; KODAIRA, CLAUDIA A.; FELINTO, MARIA C.F.C.
Afterglow of Prsup(3+) doped in cadmium silicate
2007 - RODRIGUES, LUCAS C.V.; STEFANI, ROBERVAL; CARVALHO, CARLOS A.A.; KODAIRA, CLAUDIA A.; FELINTO, MARIA C.F.C.; BRITO, HERMI F. de
Persistent luminescence of barium aluminate doped with Eusup(2+) prepared by the combustion method
2008 - RODRIGUES, L.C.V.; STEFANI, R.; CARVALHO, C.A.A.; BRITO, H.F.; KODAIRA, C.A.; FELINTO, M.C.F.C.; HOLSA, J.
Preparation and optical properties of silica material encapsulating terbium complex
2008 - LOURENCO, A.V.S.; KODAIRA, C.A.; SOUZA, E.R.; BRITO, H.F.; FELINTO, M.C.F.C.
Rare earth ions are generally used as florescent probes for analytical application because of their distinguished luminescence characteristics such as narrow spectral width, long luminescence lifetime and large Stokes shift. Luminescent functionalized silica particles have been widely used for bionalytical assays. These particles are typically generated by incorporating complex into the silica matrix.
Encapsulation study of persistent luminescent material in silica
2008 - LOURENCO, A.V.S.; RODRIGUES, L.C.V.; KODAIRA, C.A.; STEFANI, R.; CARVALHO, C.A.A.; BRITO, H.F.; FELINTO, M.C.F.C.; HOLSA, J.
Photoluminescent study of polymeric system based on rare 'beta'-diketonate crown complexes and polymethylmetacrylate film
2008 - VERLOZA, A.; KODAIRA, C.A.; FELINTO, M.C.F.C.; BRITO, H.F.
Obtained of chitosan films crosslinked by PEG 300 and 400 with europium 'beta'-diketonate chelate and influence to the exposition to ultraviolet radiation in the film lifetime
2008 - ANDRADE, O.V.; KODAIRA, C.A.; TEOTONIO, E.E.S.; FELINTO, M.C.F.C.; BRITO, H.F.
Luminescent materials containing rare earth complexes with β-diketonate ligands have been intensively studied in recent years. The rare earth complexes present characteristic narrow emission bands in the UV-Vis region, large Stokes shift and the antenna effect that enhance the overall quantum efficiency, As a result, these complexes have found wide applications as luminescent markers, photoluminescent sensors, electroluminescence devices, and multicolor display. In this work, we report the luminescent properties and photostability of chitosan films doped with Eu β-diketonates complexes. The [Eu(tta)3·(H2O)2], [Eu(tta)3·(crown)2], complexes were synthesized and characterized by elemental analysis, IR and photoluminescent techniques. The polymer films were prepared by the addition of Eu3+ complexes in methanol solution and adding to chitosan/PEG and subsequent drying at 60 o C. The thermostability of the polymer systems was investigated by thermogravimetric analysis (TGA). The excitation and emission spectra of the polymeric systems were recorded at room temperature. As shown in Fig.1 the films emit red light under UV radiation of wavelength below 360 nm arising from intraconfigurational 5D0→7 FJ transitions of Eu3+. Loss in quantum yield was observed when these films are submitted to a long time UV light exposition and this phenomenon was measured
Using lanthanide chelates and uranyl compounds for diagnostic by fluoroimmunoassays
2009 - SANTOS, ELEN G.; TOMIYAMA, CLAUDIA S.; KODAIRA, CLAUDIA A.; LOURENCO, ANA V.S.; FELINTO, MARIA C.F.C.; BRITO, HERMI F.; BRITO, MARIA E.F.
The importance of the luminescence of lanthanide ions and UO2 2+ is related to its peculiar characteristics, e.g. long lifetime and line-like emission bands in the visible, which make these ions unique among the species that are known to luminescence. Recent developments in the field of supramolecular chemistry have allowed the design of ligands capable of encapsulating lanthanide ions, thus forming kinetically inert complexes. By introduction of chromophoric groups in these ligands, an intense luminescence of the ion can be obtained via the "antenna effect", defined as a light conversion process involving distinct absorbing (ligand) and emitting (metal ion) components. In such a process, the quantities that contribute to the luminescence intensity are (i) the efficiency of the absorption, (ii) the efficiency of the ligand-metal energy transfer, and (iii) the efficiency of the metal luminescence. Encapsulation of lanthanide ions with suitable ligands may therefore give rise to "molecular devices" capable to emit strong, long-lived luminescence. Besides the intrinsic interest in their excited state properties, compounds of lanthanide ions, in particular of the Eu3+ and Tb3+ ions, and now UO2 2+ are important for their potential use as luminescent labels for biological species in fluoroimmunoassays (FIAs). This is most interesting because fluorimetric labeling represents an alternative method to the use of radioactive labels, which has long been the most common way of quantifying immunoreactions. In this article we report information about luminescent materials, which gave a good signal to quantify biological molecules by TR-FIA, DELFIA , DSLFIA, RIA and FRET.
Luminescence investigation of Eusup(3+) ion in the REsub(2)(WOsub(4))sub(3) matrix (RE=La and Gd) produced using the Pechini method
2002 - KODAIRA, C.A.; BRITO, H.F.; FELINTO, M.C.F.C.