Dissertations / Theses on the topic 'Solid-state luminescence'
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Johnson, Fiona Jane. "Electron microscopy and luminescence study of defects in semiconductor silicon." Thesis, University of Bristol, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.279773.
Full textKatelnikovas, Artūras. "Synthesis and characterization of luminescent materials for solid state light sources." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2012. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2012~D_20121227_090417-03709.
Full textŽmonija jau nuo senų senovės stengiasi prailginti dieną dirbtiniais šviesos šaltiniais. Šviesos šaltiniai vystėsi pamažu – iš pradžių buvo deginama mediena, žibalas ir žvakės, vėliau buvo išrasta kaitrinė lemputė, o dar po kurio laiko fluorescencinė lempa. Jauniausi iš dirbtinių šviesos šaltinių yra šviestukai, kurie yra pranašesni už prieš tai minėtus šaltinius savo dideliu efektyvumu. Pakeitus dabartinius šviesos šaltinius šviestukais, būtų galima sutaupyti milžinišką elektros energijos kiekį, suvartojamą apšvietimui. Pagrindinis disertacijos tikslas buvo buvo naujų liuminescencinių medžiagų, kurios gali būti sužadinamos ultravioletinę arba mėlyną spinduliuotę emituojančiais šviestukais, paieška. Iš viso pasirinktos penkios sistemos – vienas silikatas, vienas molibdatas ir trys granato struktūros junginiai. Medžiagos buvo susintetintos kietafazių reakcijų, zolių-gelių arba zolių-gelių užsiliepsnojimo metodais. Junginiai buvo legiruoti Eu2+, Eu3+ arba Ce3+ jonais. Fazinis junginių grynumas buvo patvirtintas Rentgeno spindulių difrakcijos analize. Junginių optinės savybės buvo įvertintos išmatavus atspindžio, sužadinimo ir emisijos spektrus bei liuminescencijos gesimo trukmes kambario temperatūroje. Taip pat buvo įvertinta junginių liuminescencijos gesimo trukmių ir emisijos spektrų priklausomybė nuo temperatūros, bei apskaičiuoti kvantiniai našumai ir spalviniai taškai.
Pavier, Mark Adrian. "Luminescence and non-linear optics in Langmuir-Blodgett films of rare earth containing molecular complexes." Thesis, University of Sheffield, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266802.
Full textPullin, Mark Jeffrey. "Luminescence studies of InAsâ†1â†-â†xSbâ†x low dimensional semiconductor structures for mid-infrared ambient temperature emitter applications." Thesis, Imperial College London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.264221.
Full textKang, Zhitao. "Synthesis, Characterization and Application of Luminescent Quantum Dots and Microcrystalline Phosphors." Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/13979.
Full textTodd, Devin Marlin James. "The Mechanisms of Luminescence from ZnO Under Electron Irradiation." Wright State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=wright1341465661.
Full textGuimaraes, Vinicius. "Préparation et caractérisation d'aluminoborate d'yttrium pour le développement d'une nouvelle génération de fluorophores pour l'éclairage." Thesis, Grenoble, 2012. http://www.theses.fr/2012GRENY107.
Full textCe travail de these porte sur la synthèse et la caractérization de poudres amorphes en appartenant système Y2O3 - Al2O3 - B2O3. L'objectif principal du travail a été de préparer des poudres amorphes dont la composition est proche de YAl3(BO3)4 sans terre rare en vue la réalisation de phosphores pour des dispositif d'éclairage solide à base de LED emmetant dans le proche UV. Pour la synthèse des poudres les methodes sol-gel et celles des precurseurs polymériques ont été utilisées. Nous avons ensuite optimizé les paramètres thermiques, en utilisant deux stratégies: la calcination directe et la pyrolyse suivrie d'une seconde étape de calcination. La température, le temps de recuit, vitesse de chauffage et les effect des impurities sur la photoluminescence ont été étudié. Les échantillons en poudre ont été caractérisés par les techniques d'analyse thermiques, diffraction des rayons X, la spectroscopie de photoluminescence et la spectroscopie infra-rouge, microscopies électronique à balayage et en transmission, les méthodes des analyses élémentaire et microsonde électronique, la résonance magnétique nucléaire, cathodoluminescence et le résonance paramagnétique électronique. Par l'analyse thermique, on a observé que la poudre préparée par la méthode de précurseur polymère a une température de transition vitreuse (Tg) autour de 740 ° C et des températures de cristallisation (Tx) à 815, 850 et 900 ° C. Les poudres amorphes presentent de larges bandes d'émission de photoluminescence (entre 400 et 750 nm) avec des rendements quantiques supérieurs à 90% pour une excitation de 365 nm. De plus, les poudres microscopiques obtenu sont chimiquement homogene avec des composition très proche de celle initialmente visée YAl3(BO3)4 lorsque les échantillons sont recuits à des températures voisine du Tg. Au-dessus de cette température, la poudre commence à se cristalliser conduisant à réduction de l'intensité de PL. D'autres compositions ont été étudiées en augmentant la quantité relative de Y2O3, Al2O3 et B2O3, en éliminant complètement l'yttrium, ou en ajutant SiO2. Finalement, les premiers mesures de coordonnées de couleur et les essais préliminaires sur la stabilité thermique et photométrique sont très prometeur. En effet, outres les rendemente specifiques de luminescence très elevés ces luminophores émitent de lumiére très chaudes
BOMFIM, JUNIOR FRANCISCO A. "Producao e caracterizacao de vidros de oxidos de metais pesados dopados com terras-raras e nanoparticulas metalicas." reponame:Repositório Institucional do IPEN, 2009. http://repositorio.ipen.br:8080/xmlui/handle/123456789/9433.
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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
Hilder, Matthias. "Photophysical properties of europium and terbium benzoate complexes in the solid state : interrelation between composition, structure and optophysical properties." Monash University, School of Chemistry, 2004. http://arrow.monash.edu.au/hdl/1959.1/9641.
Full textJAKUTIS, NETO JONAS. "Low gain Nd:YLF lasers operating in the quasi-three level transition and in Raman lasers." reponame:Repositório Institucional do IPEN, 2012. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10200.
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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
Ardicoglu, Burcu. "Synthesis Of Rare-earth Doped Lithium Triborate." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/3/12606354/index.pdf.
Full textC for 14 hrs. The expected reaction is given below. Li2CO3 + 6H3BO3 -->
2LiB3O5 + CO2 + 9H2O Prepared LiB3O5 and Gd2O3, La2O3 and Y2O3 samples were weighed separately at different concentrations and ground together. The mixture was then heated at 750 º
C for 7 hrs. Characterization of the new products was done by X-Ray Diffraction (XRD) and Infrared (IR) analysis. Differential Thermal Analysis (DTA) was used for examination of the thermal properties of the compounds, morphology of new compounds was observed by Scanning Electron Microscopy (SEM). The compounds are then subjected to thermoluminescence (TL) studies. From the XRD studies, no change in the LBO phase related to the addition of rareearth elements was observed. However, peaks of those elements were also become apparent. IR analysis showed that there is no change related to B-O link with the addition of rare earth elements. DTA studies showed that the melting point of LBO decreases with the addition of rare earth elements. In the SEM images, two phases belonging to particles of rare earth elements and lithium triborate were observed clearly. With the TL analysis, it was considered that the samples show dose response but also it was realized that they are affected by fading.
Pedroso, Cássio Cardoso Santos. "Investigação da luminescência persistente dos materiais Lu2O3:TR3+,M (TR,M: Pr,HfIV; Eu, Ca2+ ou Tb,Ca2+) preparados pelo método de estado-sólido assistido por micro-ondas." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/46/46136/tde-21062017-092436/.
Full textPersistent luminescence is a phenomenon where the material emits radiation from seconds to several hours after cessation of irradiation (light, UV radiation, electron beam, etc.). The persistent luminescence mechanisms are not entirely established, however. In this work, the materials Lu2O3:TR3+,M (TR,M: PrHfIV; Eu, Ca2+ or Tb,Ca2+) were prepared by MASS method as well as compared to these materials synthetized by ceramic method. The advantages of MASS method include short processing time, selective dielectric heating, low energy consumption and use of inexpensive equipment (domestic microwave oven), often affording high-purity and high-yield products. The materials were characterized by Infrared absorption spectroscopy (IR), Raman spectroscopy, X-ray powder diffraction (XPD), Scanning electron microscopy (SEM), X-ray absorption near edge structure (XANES), Extended X-ray absorption fine structure (EXAFS), X-ray excited optical luminescence (XEOL), photoluminescence spectroscopy in the UV-Visible range, photoluminescence spectroscopy in the UV-UV vacuum region and thermoluminescence (TL). The phosphorsLu2O3:TR3+,M (TR,M: Pr,HfIV; Eu, Ca2+ or Tb,Ca2+) were rapidly (22-26 min) and successfully prepared by MASS method using a domestic microwave oven, carbon as susceptor, fluxes (H3BO3 or Na2CO3) and without special gases application. All materials prepared with H3BO3 flux exhibit LuBO3 impurities that were quantified by Rietveld refinement. The flux and dopants does not considerably affect the crystalline structure of the C-Lu2O3 host matrix. Scanning electron micrographs suggest that Na2CO3 flux and nitrates precursors produce Lu2O3 particles of small size due to the gases evolution from the decomposition of these compounds. On the other hand, the materials prepared from oxides precursors have particles of large size and H3BO3 flux induces particle xi aggregation. The carbon used as the susceptor generates CO gas, leading to complete reduction of TbIV to Tb3+ and partial conversion of PrIV to Pr3+ present in the Tb4O7 and Pr6O11 precursors, as indicated by XANES. Persistent luminescence spectra of the materials show emission in the red/NIR, reddish orange and green ranges assigned to the 4fN → 4fN transitions characteristics of Pr3+, Eu3+ and Tb3+ ions, respectively. Differences between the spectra recorded under UV excitation and after ceased the irradiation can be explained by the predominant persistent luminescence emission of TR3+ ion in the S6 site rather than TR3+ in the C2 site. In addition, inclusion of HfIV and Ca2+ codopants in the Lu2O3 host increases the emission intensity and duration of persistent luminescence due to generation of traps caused by charge compensation in the lattice as well as these metal ions in the Lu3+ sites. The photonic materials prepared by MASS method with H3BO3 flux show higher persistent luminescence performance than those prepared by the ceramic method or MASS without flux. The persistent luminescence mechanisms were developed through similar principles based on experimental data of band gap energy, energy level positions of TR3+/2+ ions in the host and traps energy. This similarity confirms the consistency of the interpretation of experimental data for the Lu2O3:TR3+,M materials and encourages the expansion of similar models for other persistent luminescence materials. Color tuning of persistent luminescence in Lu2O3:TR3+,M (TR,M: Pr,HfIV; Eu,Ca2+ or Tb,Ca2+) provides potential applications in bioimaging as well as in solar cell sensitizers.
JAGOSICH, FABIO H. "Estudos dos processos de transferência de energia dos íons de Ersup(3+) e Hosup(3+) para os íons de Ndsup(3+), Tbsup(3+) e Eusup(3+) no cristal de LiYFsub(4) e no vidro ZBLAN para a otimização de meios laser ativos que operam na região de 3 microns." reponame:Repositório Institucional do IPEN, 2006. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11432.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
FAPESP:00/11446-0
López, Vidrier Julià. "Silicon Nanocrystal Superlattices for Light-Emitting and Photovoltaic Devices." Doctoral thesis, Universitat de Barcelona, 2015. http://hdl.handle.net/10803/334396.
Full textEls nanocristalls de silici han esdevingut objecte d'estudi durant l'últim quart de segle, degut a què presenten, a causa de l'efecte de confinament quàntic, unes propietats físiques dependents de la seva mida. A més, la compatibilitat del silici massiu amb la ben establerta tecnologia microelectrònica juga en favor de la seva utilització i el seu desenvolupament per a futures aplicacions en el camp de la fotònica i l'optoelectrónica. El control del creixement de nanocristalls de silici es pot dur a terme mitjançant el dipòsit de superxarxes d'entre 2 i 4 nm de gruix, on capes de material estequiomètric basat en silici s'alternen amb altres de material ric en silici. Un posterior procés de recuit a alta temperatura permet la precipitació de l'excés de silici i la seva cristal.lització, tot originant una xarxa ordenada de nanocristalls de silici de mida controlada. En aquesta Tesi, s'han estudiat les propietats estructurals, òptiques, elèctriques i electro-òptiques de superxarxes de nanocristalls de silici embeguts en dues matrius diferents: òxid de silici i carbur de silici. Amb tal objectiu, s'han emprat tot un seguit de tècniques experimentals, que comprenen la caracterització estructural (microscòpia electrònica de transmissió i d'escombrat, difracció de raigs X), òptica (espectroscòpies d'absorció òptica, de fotoluminescència i dispersió Raman) i elèctrica / electro-òptica (caracterització intensitat-voltatge en foscor o sota il.luminació, electroluminescència, resposta electro-òptica), entre d'altres. Des del punt de vista del material, s'han estudiat les propietats estructurals òptimes per tal d'obtenir un perfecte ordenament en la xarxa de nanocristalls, una major qualitat cristal.lina i unes propietats d'emissió òptimes. L'optimització del material s'ha dut a terme en vistes a la seva utilització com a capa activa dins de dispositius emissors de llum i fotovoltaics, l'eficiència dels quals ha estat monitoritzada segons els diferents paràmetres estructurals (gruix de les capes nanomètriques involucrades, estequiometria, temperatura de recuit). Finalment, els nanocristalls de silici embeguts en òxid de silici han demostrat un major rendiment com a emissors de llum, mentre que una matriu de carbur de silici beneficia les propietats d'absorció i extracció (fotovoltaiques) del sistema.
Jama, Mariel Grace. "Semiconductor composites for solid-state lighting." Thesis, Bordeaux, 2015. http://www.theses.fr/2015BORD0207/document.
Full textLuminescent organic phases that are embedded in a conductive inorganicmatrix is proposed in this study for the active layer of a hybrid light-emitting diode. Inthis composite, the organic dye acts as the radiative recombination site for chargecarriers that are injected into the inorganic ambipolar transporting matrix. As one ofthe candidate material combinations, bilayer and composite thin films of ZnSe and ared iridium complex (Ir(BPA)) organic light emitter were prepared in situ via UHVthermal evaporation technique. The energy band alignments measured byphotoelectron spectroscopy (PES) for the ZnSe/Ir(BPA) bilayer and ZnSe+Ir(BPA)composite reveal that the HOMO and LUMO of the organic dye are positioned in theZnSe bandgap. This lineup provides the required energetic driving forces for electronand hole transfers from ZnSe to Ir(BPA). By interpreting PES data, the chemicalcomposition of the interfaces were also determined. The ZnSe/Ir(BPA) interface isreactive even though it is of high material purity. Meanwhile, the Ir(BPA)/ZnSeinterface does not exhibit material purity. This is accounted to the nature of ZnSeevaporation as individual Zn and Se2 fluxes, coupled with chemical interactions withthe Ir(BPA) substrate. The interface is, thereby, composed of an abundance of Se0phases, sparse ZnSe phases, reduced Se and oxidized dye molecules, and Znatoms that are intercalated into the Ir(BPA) substrate. PES of the ZnSe+Ir(BPA)composites reveals similar trends to the Ir(BPA)/ZnSe interface. A faded areal andintermittent red light emissions were observed from devices that incorporatedalternating layer sequences of ZnSe and Ir(BPA) for the active layer
Bain, Fiona Mair. "Yb:tungstate waveguide lasers." Thesis, University of St Andrews, 2010. http://hdl.handle.net/10023/1698.
Full textTARELHO, LUIZ V. G. "Caracterizacao espectroscopica e dinamica temporal dos processos de transferencia de energia entre os ions Tm sup(3+) - Ho sup(3+) e Yb sup(3+) - Tm sup(3+) em cristais de LiYF sub(4) e LiLuF sub(4)." reponame:Repositório Institucional do IPEN, 2001. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10980.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
FAPESP:95/03214-1
Kenta, Nishino. "Advanced Luminescent Materials Based on Conjugated Carboranes." 京都大学 (Kyoto University), 2017. http://hdl.handle.net/2433/225625.
Full textYu, Tingting. "Solid state luminescent molecules, macromolecules and materials, their response to stimuli and their applications in devices." Thesis, Lyon, 2020. http://www.theses.fr/2020LYSEN061.
Full textIn this thesis, we developed new luminescent conjugated chromophores presenting an alternation of electron donor and acceptor groups, with a specific focus on their emission properties in aggregates or solid states in far-red or near infrared region. We studied the influence of chain length and donor/acceptor substitution not only on the optical properties of the isolated compounds, but also (and especially) on the material in its aggregated state. Finally, taking advantages of these specific properties of some of the as-designed candidates, we explored their potential applications ranging from fluorochromic stimuli-responsive sensors (in film form) to red and NIR luminescent two-photon probes for biological imaging. The main achievements of this thesis are the following: 1) new alternating triarylamine or carbazole / tetraphenylethylene (TPE) polymers were synthesized. Their solid state luminescence poseeses typical J-aggregates emission features in solid state, unusual in TPE derivatives that we relate to the linear polymeric nature of the object; 2) A new family of diphenylamine / benzobisthiazole chromophores and derived oligomers were synthesized . Their luminescence properties present a marked sensitivity to protonation, which we took advantage of in the making of acid-base responsive luminescent devices; 3) we explored the possibility of additional chemical transformations of the newly designed chromophore, in order to achieve solid state NIR emission, in particular by means of a change in the character of the electronic transition from Intra-Molecular Charge Tranfer (ICT) to Cyanine transition owing to benzothiazole quaternarization. Other modifications resulted in improvement of their AIE properties, bioavailability and selectivity of their cellular compartments staining ability; 4) These new compounds present a reversible photoinduced “on-off” switching of their luminescence properties, which might present an interest in the design of contrast-agents for super resolution imaging
Ashenhurst, James Alexander. "The synthesis of blue-luminescent aluminum complexes and their characterization by solid-state ²§7 Al NMR spectroscopy." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0006/MQ42583.pdf.
Full textMagne, Sylvain. "Etat de l'art des lasers à fibre : étude d'un laser à fibre dopée ytterbium et spectroscopie laser de fibres dopées." Saint-Etienne, 1993. http://www.theses.fr/1993STET4027.
Full textUmuhire, Mahoro Gilbert. "Development of new cationic copper (l) complexes for white light-emitting electrochemical cells." Thesis, Normandie, 2021. http://www.theses.fr/2021NORMC202.
Full textNew cationic copper(I) complexes with the general formula of [Cu(P^P)(N^N)][PF6] where P^P is a chelating bis-phosphine ligand bis-[2-(diphenylphosphino)phenyl]ether (DPEPhos) and N^N 2,2-bis-pyridyl ligand derivatives were developed. The complexes featured solid-state emissions covering the entire visible spectrum and the presence of the thermally activated delayed fluorescence (TADF) was demonstrated. Furthermore, the complexes were incorporated in light-emitting electrochemical cells (LEC) and led to devices emitting in different colors, i.e., blue, green, yellow, orange, red, and ultimately white-emitting LECs
Gallinelli, Thomas. "Les concentrateurs luminescents pour l’amplification de la brillance des diodes électroluminescentes : application au pompage laser." Thesis, Sorbonne Paris Cité, 2017. http://www.theses.fr/2017USPCD086/document.
Full textElectroluminescent diodes are popular sources due to their low cost, their reliability, and their excellent luminous efficiency. However, the power density of lambertian sources such as LED cannot be improved with linear optics which makes them not suited to laser pumping. We propose to increase the LED power density by one order of magnitude by coupling them in luminescent concentrators (LC). We studied these luminescent concentrators as illuminating sources using LC made of cerium doped YAG crystals (Ce:YAG) and we analyzed their performances using ray tracing simulations. For a deeper understanding of the challenge of extracting trapped rays in luminescent concentrators, a fully analytical model is also presented and used to study the influence of simple geometrical modifications such as wedging or roughening the luminescent concentrators output face. A significant increase of the light intensity was experimentally observed as well as a shrinking of the angular distribution. Finally, we set up a full organic structure with a LED source associated to thin film luminescent concentrators in order to pump micrometer-sized multimode waveguides. We demonstrated a one-order of magnitude amplification compared to a direct pumping with the same power density. It makes the LED/concentrator light source well suited for integrated optics and opens new perspectives whenever
Rocca, René Rojas. "Estudo comparativo entre as propriedades dos centros luminescentes e paramagnéticos da antigorita e da lizardita do grupo da SERPENTINA: `Mg IND.3´[Si IND.2´`O IND.5´]`(OH) IND.4´." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/43/43134/tde-02062008-142059/.
Full textIn this work, we are describing crystals luminescent properties of Antigorite (monoclinic, Mg3-x[Si2O5](OH)4-2x) and Lizardite (triclinic, Mg3[(Si,Fe)2O5](OH)4). They were studied simultaneously applying several techniques, like: Thermoluminescence (TL), Optical Absorption (OA), Electron Paramagnetic Resonance (EPR), X-rays diffraction and Inductively Coupled Plasma (ICP). Using cold pressed elements and heating the samples to 350 oC for TL measurements, we can observe reproductive peaks. Antigorita show well differentiated peaks and intensities, but Lizardite show overlapped and similar intensity peaks. Peaks of both samples occur around 150, 200, 250, 300 oC, and all them grow linearly up to 2 kGy, saturating for high doses, except 250 oC peak which continue growing with dose until 172 kGy. TL peaks trap parameters and lifetimes were calculated, the curves were fitted using the GCD method with second order kinetic. The EPR spectrum shows 6 hyperfine structure lines, characteristic of Manganese, besides lines due to Iron. It was possible also to observe two super hyperfine Mn2+ lines. The EPR signal does not change with irradiation dose in both crystals. These impurities were also detected in the ICP analysis. The OA spectrum of lizardite show bands from 370 to 470 nm which were not observed in antigorite samples probably related to Fe3+ and Mn2+. In the infrared region several (OA) bands of Mg-OH combination were observed. Again the OA spectrum of these crystals does not change with irradiation dose. We conclude that TL samples peaks around 150, 200, 250, 300 oC can be used for radiation ionizing dosimetry (y-rays and B- particle) for intermediate and high doses.
Posavec, Tony. "An Investigation into the Fluorescence of Polymers." University of Akron / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=akron1499353221343727.
Full textQueiroz, Thiago Branquinho de. "Estudos espectroscópicos de sistemas luminescentes hóspede/hospedeiro." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/76/76131/tde-04042013-112539/.
Full textThis work presents the preparation and characterization of luminescent materials based on mesoporous host matrices loaded with highly emissive molecular species (the organic dye Rhodamine 6G (R6G), and the Iridium (III) complex (N,N-trans-[Ir-(1-benzyl-4-(2,4-difluorophenyl)-1,2,3-triazole)2(4,4´-dimethyl-2,2´-bipyridine)]+). In the case of R6G loading we have explored purely inorganic and organically modified silica compositions, as well as sodium-aluminosilicate glasses. The Ir(III) complex was loaded solely into the sodium-aluminosilicate glasses. The host matrices were designed and developed, via sol gel methodology, in consonance with the physicalchemical properties of the emitters aiming at improved molecular incorporation and dispersion through various chemical interactions. For instance, in the case of silica modified with aromatic groups, interaction among such groups with the unsaturated bonds of the R6G molecule is expected, resulting in higher molecular incorporation and retention efficiencies, as well as decreased aggregation. In the case of the sodium-aluminosilicate glasses, the loading of both cationic species, dye and Ir(III) complex, takes place via ionic exchange with Na+ at the (AlO4)- network sites. In this case, control of molecular dispersion of the emitting center was attempted by varying the Si/Al ratio in the matrix (between 2 and 9), so as to promote the spatial distribution of the active anionic sites among neutral SiO4 sites. Through these approaches, we were able to obtain materials with high chemical stability, high molecular dispersion, facile and low cost obtainment and excellent photophysical properties. Prior to loading, the matrices were characterized from the structural point of view through several solid state NMR techniques, XRD and N2 sorption. The photophysical properties of the emitters in solution and in the solid state were characterized and compared through UV-Vis absorption and emission, excited state lifetimes and absolute quantum yields measurements. Moreover, the R6G loaded materials were tested in a laser cavity with respect to their laser efficiencies and photo stabilities. The results of these systems were analyzed in terms of the Single Exciton Theory. As for the materials loaded with Ir(III) complex, the photophysical studies were complemented by a theoretical approach though Density Functional Theory, DFT. From the conventional treatment performed for iridium (III) complexes in liquid state, alternative methods were developed and analyzed for treating the problem in the host matrix. The applied formalism contributed to a detailed description of the electronic structure of the complex, as well as of the changes perceived due to insertion in the matrix.
COURROL, LILIA C. "Estudo quantitativo da luminescencia do Hosup3+ em cristais de YLF e HoLF e analise da dinamica dos processos de transferencia de energia do Ybsup3+ para os ions de Tmsup3+ e Hosup3+ em cristais." reponame:Repositório Institucional do IPEN, 1994. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10388.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
FAPESP:93/04231-1
Freitas, Vânia Patrícia Castro Teixeira. "Organic-inorganic hybrids for green photonics." Doctoral thesis, Universidade de Aveiro, 2016. http://hdl.handle.net/10773/17325.
Full textThe presente work aims to synthesize new bridge silsesquioxanes organic-inorganic hybrid materials, and characterize the local structure and photoluminescence properties overlooking potential applications in the area of green photonics, namely, in solid-state lighting and luminescent solar concentrators. In this context, three distinct families of materials based on six precursors which differ in their structural organization were synthesized, i.e. precursors with structure: 1) linear where the organic component is based on malonamide group, P2-m and P4-m; 2) linear which has been added an aromatic ring whose organic part is based on amide and/or thioamida, P(UU), P(UT) and P(TT) and 3) branched which the organic component is based on amide group, t-UPTES (5000). Two organic-inorganic hybrids (M2-m e M4-m) which results from hydrolysis and condensation of the precursors P2-m e P4-m were synthetized. The role of the presence of one or two malonamide groups was studied in terms of local structure and photoluminescence properties. Three organic-inorganic hybrids H(UU), H(UT) and H(TT) based on P(UU), P(UT) and P(TT) were synthesized and structurally characterized aiming to study the role of the hydrogen bond in the self-assembling of these materials. The presence of different types of hydrogen bonds (bifurcated, linear and cyclic) induces different conformations which affect the physical properties (mechanical and optical) of the materials. Hybrids based on t-UPTES(5000) precursor were synthesized based on different synthesis strategies. Changing the concentration of HCl and water content as well as the synthesis in a controlled environment allowed the improvement of the optical properties of this system, in particular, the absolute emission quantum yield and the absorption coefficient. In addition, it were studied the recombination mechanisms responsible for the emission through the comparison between the corresponding photoluminescence properties of the organic and inorganic models. Finally, due to the structural simplicity of the precursors P2-m and P4-m, these were doped with Eu3+. The local structure of the corresponding hybrids shows local coordination between the ion and the host. Efficient materials concerning the absolute emission quantum yield values motivated the development of luminescent solar concentrators with a maximum absolute emission quantum yield of 0.600.06 and optical conversion efficiency in the absorption spectral region (300-380 nm) of 12.3%.
O presente trabalho propõe sintetizar novos materiais híbridos orgânicos-inorgânicos do tipo silsesquioxanos em ponte e caracterizar a sua estrutura e propriedades de fotoluminescência com vista a potenciais aplicações na área da fotónica sustentável, nomeadamente, iluminação de estado sólido e concentradores solares luminescentes. Neste âmbito, foram sintetizadas três famílias distintas de materiais baseados em seis precursores que diferem na sua organização estrutural, ou seja, precursores com estrutura: 1) linear onde a componente orgânica é baseada no grupo malonamida, P2-m e P4-m; 2) linear onde foi adicionado um anel aromático cuja componente orgânica é baseada em amida e/ou thioamida, P(UU), P(UT) e P(TT), e 3) tri-ramificada onde a componente orgânica é baseada no grupo amida, t-UPTES(5000). Dois híbridos orgânicos-inorgânicos (M2-m e M4-m) que resultam da hidrólise e condensação dos precursores P2-m e P4-m foram sintetizados. O papel da presença de um ou dois grupos malonamida foi estudado em termos de estrutura local e propriedades de fotoluminescência. Três híbridos orgânicos-inorganicos, H(UU), H(UT) e H(TT), baseados, respetivamente, em P(UU), P(UT) e P(TT), foram sintetizados e caracterizados estruturalmente com o objetivo de estudar o papel das ligações de hidrogénio na auto-organização destes materiais. A presença de diferentes tipos de ligações de hidrogénio (bifurcada, linear e cíclica) induz diferentes tipos de configurações que têm influência nas propriedades físicas (mecânicas e óticas) dos materiais. Híbridos baseados no precursor t-UPTES(5000) foram sintetizados tendo em conta diferentes estratégias de síntese. A variação da concentração de HCl e quantidade de água bem como a síntese em ambiente controlado permitiram melhorar as propriedades óticas deste sistema nomeadamente, o rendimento quântico absoluto e o coeficiente de absorção. Foram também discutidos, os mecanismos de recombinação responsáveis pela emissão através da comparação das propriedades de fotoluminescência observadas nos correspondentes modelos orgânicos e inorgânicos. Finalmente, devido à simplicidade estrutural os precursores P2-m e P4-m, estes foram dopados com Eu3+. A estrutura local dos correspondentes híbridos mostra coordenação local entre o ião e a matriz. Materiais eficientes do ponto de vista de rendimento quântico absoluto motivaram o desenvolvimento de concentradores solares luminescentes que apresentam rendimento quântico absoluto máximo de 0.600.06 e eficiência ótica de conversão na região espetral de absorção (300-380 nm) de 12.3 %.
Ljubica, Đačanin. "Luminescentna svojstva litijum-indijum oksida dopiranog jonima retkih zemalja." Phd thesis, Univerzitet u Novom Sadu, Prirodno-matematički fakultet u Novom Sadu, 2015. https://www.cris.uns.ac.rs/record.jsf?recordId=90817&source=NDLTD&language=en.
Full textThe subject of this dissertation are powders of lithium-indium oxide doped with different rare earth ions (Eu3+; Sm3+; Er3+; Yb3+), synthesized by solid-state reaction. Lithium-indium oxide has a variety of potential applications in the form of scintillators, phosphor matrixes for rare-earth ions, storage and energy conversion devices and photocatalysts. In this study the optimal method of synthesis of pure-phased powders of new phosphors LiInO2:RE3+ was determined. Also, their detailed characterization using the X-ray diffraction, scanning electron microscopy, thermogravimetry and differential thermal analysis, Raman spectroscopy and diffuse-reflection spectroscopy was performed. Photoluminescence spectroscopy was applied to investigate the properties crucial for the application of these materials. Emission spectra and lifetime values, showed these materials are potential efficient phosphors. Examining the emission of LiInO2:Er3+ sample at different temperatures indicated that this is a very good temperature sensor in the temperature range (10-300) K.
Lorenz, Tom. "Recycling Seltener Erden aus Permanentmagneten und Leuchtstoffabfällen mittels Feststoffchlorierung." Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2018. http://nbn-resolving.de/urn:nbn:de:bsz:105-qucosa-237116.
Full textAguir, Khalifa. "Nouvelle methode de pulverisation reactive : synthese et caracterisation de films minces de ga::(x)as::(1-x) amorphe hydrogene." Toulouse 3, 1987. http://www.theses.fr/1987TOU30174.
Full textVandenBerghe, Kenneth L. "Solid state luminescent materials : new and improved." Thesis, 1996. http://hdl.handle.net/1957/34187.
Full textLiu, Chieh-min, and 劉杰旻. "Solid-State Synthesis and Luminescence Properties of La1-xPrxTiNbO6." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/08237061865524182370.
Full text國立成功大學
材料科學及工程學系碩博士班
97
In this study, novel phosphors based on LaTiNbO6 system have been synthesized by solid-state method. Effects of contents of Pr3+ on crystal structure and photoluminescence properties by 383 nm and 420~450 nm pumping source of synthesized phosphors were also discussed. The results revealed that the structure of LaTiNbO6 is monoclinic under the calcining temperature of 1300℃ for 72 hours while the structures of La1-xPrxTiNbO6 (x≧20%) are orthorhombic and the structures of La1-xPrxTiNbO6 (0
Liao, Yu-Jiu, and 廖宇久. "Luminescence property of ZnS-based phosphor prepared by solid-state sintering." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/39353483853761111412.
Full text國立高雄應用科技大學
光電與通訊研究所
94
ZnS is a wide-gap (3.66 eV) II-VI compound semiconductor material and is commercially used as phosphor for electroluminescence devices. ZnS has good luminescence property, it is a candidate material for phosphors that emit visible light. The major and important applications of phosphor are in light sources, display devices, and high energy radiation detector. Two subjects on this thesis have been discussed. The first one is the synthesis of the traditional ZnS-based phosphors. The effect of preparation parameters, such as synthesis temperature, sintering time, dopants and doping concentration, on the luminescence characteristics of phosphor was studied. X-ray diffractometer (XRD), photoluminescence (PL), cathodeluminescence (CL) and scanning electron microscopy (SEM) were used to analyze the characterizations of crystalline structure, luminescence and microstructure of phosphor. From the XRD pattern, transformation temperature of the ZnS phosphor was determined. It was also found that the luminescence property of host lattice changed along with the amount of hexagonal phase. The higher the firing temperature, the higher the amount of hexagonal phase could be found. From photoluminescence and cathodeluminescence spectra, luminescence intensity related to the sintering temperature, doping concentration and sintering time were evaluated. When ZnS doped with Mn and Ce ion, a yellow-orange emission wavelength around 568 nm is observed. Increasing the doping concentration, the concentration quenching effect was observed. When the co-doping concentration is 0.9 mol%, sintering temperature is 1200℃ and sintering time is 1 hour, the optima emission efficiency of phosphor was achieved. The phosphor which was synthesized in the first subject was applied to the second subject subsequently. The ZnS-based phosphor used as the phosphor layer for electroluminescence device, which was prepared by screen-printing method. After the electrode was fabricated, a yellow-orange EL device was obtained.
Juang, Jung-ying, and 莊忠穎. "Solid-State Synthesis and Luminescence Properties of SrTiO3:Er3+ and BaSrTiO3:Er3+." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/93143084933279221141.
Full text國立臺南大學
材料科學系碩士班
99
After being replaced by various positive ions, the properties of SrTiO3 are different due to the changes in temperature and in ratio of compositions. SrTiO3 is an excellent candidate system in lead-free piezoelectric materials because of its a wide range of applications in integrated microelectronics. Nevertheless, the luminescence properties of SrTiO3 on are also studied. In the study, novel phosphors based on Sr1-1.5xErxTiO3(x=0~ 0.18)have been synthesized by solid-state method. Effects of contents of Er3+ on crystal structure and photoluminescence properties by 514.5 nm Ar+ laser excitation were also discussed. The regions of emission are 516~537 nm(2H11/2→4I15/2)、537~570 nm(4S3/2→4I15/2)、640~690 nm(4F9/2→4I15/2)and 830~870 nm(4S3/2→4I13/2). The results revealed that the emission intensity enlarges when the growth temperature(1100 °C、1200 °C、1300 °C and 1400 °C)rises. The results show the strongest emission intensity occurs when doping 11 mol% at 1300 °C and 11 mol% at 1400 °C , respectively. While changing the ratio of lattice, Sr0.9Ba0.1TiO3:Er3+ possesses the most preferred emission intensity. So we have found that luminescence emission changes as the structure of lattice varies.
Yi-RuLee and 李宜儒. "Solid state Synthesis and Luminescence Properties of Ca1-2XNaXDyXWO4, Ba1-2XNaXDyXWO4 and Ca1-2XNaXDyXNb2O6 compounds." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/33801602156726795898.
Full text國立成功大學
材料科學及工程學系碩博士班
100
The aim of this study was to develop some new phosphor whose host material contained no rare-earth (RE) element. We chose CaWO4, BaWO4 and CaNb2O6 as the RE-free host and studied the spectroscopic properties of Dy3+ in these hosts. Na+ was co-doped with Dy3+ in order to maintain the overall charge neutrality. The experiment results showed that after sintering at 900 C for 20 hours Ca0.96Dy0.02Na0.02WO4 and Ba0.96Dy0.02Na0.02WO4 crystallized in the monoclinic Scheelite structure, while the sintering temperature for Ca0.96Dy0.02Na0.02Nb2O6 to form the monoclinic tungsten-bronze (MTB) was 1100 C. The later showed a low temperature phase transition and after annealing at 650 C for 10 hours, the sample transformed to the tungsten-bronze (TTB) structure. Photoluminescence spectroscopy showed that under the 350 nm excitation Ca0.96Dy0.02Na0.02WO4, Ba0.96Dy0.02Na0.02WO4, and Ca0.96Dy0.02Na0.02Nb2O6 gave out two dominant emissions at 487 nm (4F9/2→6H15/2, blue) and 574 nm (4F9/2→6H13/2, yellow), respectively. The yellow lights were stronger than the blue lights in all three phosphors. The CIE color coordinates for Ca0.96Dy0.02Na0.02WO4 and Ba0.96Dy0.02Na0.02WO4 were calculated to be (0.34, 0.33) and (0.32, 0.29) respectively, which were all located in the white region. The yellow emission of the MTB-structured Ca0.96Dy0.02Na0.02Nb2O6 was far too stronger and the mixture of the two emissions was not in the white region. However, in the TTB-structured Ca0.96Dy0.02Na0.02Nb2O6 the yellow emission was reduced, presumably arising from the higher symmetry of the structure. The CIE color coordinate of the TTB-structured Ca0.96Dy0.02Na0.02Nb2O6 was (0.32, 0.30), which was also in the white region. Key words:phosphor,Scheelite,rare earth
Schaffers, Kathleen I. "A study of new optical materials I. Crystal-chemical development of new optical frequency converters II. New hosts for Cr3+ luminescence and lasing." Thesis, 1992. http://hdl.handle.net/1957/32543.
Full textGraduation date: 1993
Fontes, Luís Filipe Baptista. "Synthesis and photophysical properties of triphenylpyridine derivatives." Master's thesis, 2019. http://hdl.handle.net/10773/30093.
Full textNeste estudo foram sintetizados e caracterizados derivados de trifenilpiridinas. Os derivados de trifenilpiridina apresentaram fluorescência, com alguns derivados a apresentarem rendimentos quânticos de fluorescência acima do composto de referência (antraceno). O composto [4-(2-(2-metoxifenil)-6-fenilpiridin-4-il)-N,N-dimetilanilina] apresenta ser o derivado com valores superiores de rendimento quântico de fluorescência. Os estudos realizados permitiram identificar a importância do grupo 2- (piridin-2-il)fenol para obter fluorescência em estado sólido e não em solução. Foi tentada a complexação de boro com os derivados de 2-(piridin-2-il)fenol com eterato de trifluoreto de boro no entanto os complexos obtidos não mostraram ser estáveis em solução. Cinco dos derivados foram analisados por cristalografia de raio-x: -os resultados permitiram avaliar as interações intramoleculares e intermoleculares em estado sólido. Todos os derivados apresentaram fluorescência em estado sólido demonstrando o potencial de fluoróforos baseados em trifenilpiridina para futuros estudos de luminescência em estado sólido.
Mestrado em Química
Mofokeng, Sefako John. "Investigation of up and down-converting rare earth ions doped ZnTiO3 for photovoltaic applications." Thesis, 2019. http://hdl.handle.net/10500/26702.
Full textCollege of Engineering, Science and Technology
WU, Yao-Hsuan, and 巫耀玄. "Studies of photophysical properties of solid-state carbon nano-dot thin films for greener luminescent solar concentrators." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/nx66pf.
Full text中原大學
奈米科技碩士學位學程
106
A luminescent solar concentrator (LSC) is consisted of the luminophores and a waveguide that can be used to spatially concentrate both direct and diffused sunlight without the need of complex and expensive solar-tracking and cooling systems. Recently, colloidal quantum dots (CQDs) with some unique photophysical properties have attracted much attention as the luminophores in LSCs. However, most of mature CQDs contain heavy metals and need to be synthesized in the hazardous organic solvent. In addition, they also suffered from concentration-induced quenching (CIQ), thus the loading concentration of luminophores doped in LSCs is restricted. Unfortunately, this would reduce the light-absorbing efficiency, leading to large transmission losses. To address all the issues mentioned previously, organosilane-functionalized carbon nanodots (Si-CNDs) were synthesized based on cost-effective, earth-abundant precursors using a simple hydrothermal method. Such Si-CNDs exhibit some unique photophysical properties, including large absorption coefficient, high PL quantum yields (PL-QYs) and resistance to CIQ effect. Due to good film-forming properties, greener LSCs with different loading concentrations can be simply fabricated by directly cross-linking Si-CNDs on the glass waveguide. The LSCs are highly transparent even under high loading concentration up to 75 wt%, indicating high uniformity of Si-CND distribution. The LSCs with 25 wt% loading contents still possess high solid-state PL-QYs up to ~41% upon the calibration of reabsorption losses and high internal quantum efficiency of ~23% due to low scattering losses. We expect our demonstration can pave a way to further design efficient greener LSCs after further reducing the reabsorption losses.
Mukherjee, Soham. "Local Structure-Property Relationship in Some Selected Solid State Materials." Thesis, 2015. http://etd.iisc.ernet.in/2005/3931.
Full textMukherjee, Sanjoy. "Investigations of Structure-Property Relationships in NPI and BODIPY Based Luminescent Material." Thesis, 2015. http://etd.iisc.ernet.in/2005/3933.
Full textSushrutha, S. R. "Syntheses, Structures and Characterization of New Coordination Polymer Compounds." Thesis, 2016. http://etd.iisc.ernet.in/handle/2005/2978.
Full textJana, Ajay Kumar. "Metal-Organic Framework (MOF) Compounds : Synthesis, Structure, Sensing and Catalytic Studies." Thesis, 2017. http://etd.iisc.ernet.in/2005/3774.
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