Dissertations / Theses on the topic 'LUMINESCENCE MATERIALS'
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1
Miller, Paul Francis. "Luminescence studies of molecular materials." Thesis, Imperial College London, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342250.
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Brooks, Robert. "Ion beam induced luminescence of materials." Thesis, University of Sussex, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.391861.
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Rocha, Lucas Alonso [UNESP]. "Materiais meso-estruturados luminescentes." Universidade Estadual Paulista (UNESP), 2010. http://hdl.handle.net/11449/105768.
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rocha_la_dr_araiq.pdf: 3758896 bytes, checksum: 8f9b1dddc8f92a0c77915bd317de357f (MD5)Partículas esféricas de sílica mesoporosa foram obtidas a partir da síntese “template” pelo processo de pirólise de aerossol. O processo foi otimizado para a obtenção de materiais mesoporosos sem resíduos orgânicos e preparados em uma única etapa, eliminando assim, a longa etapa de remoção do surfactante na metodologia tradicional (tratamento térmico ou extração soxhlet, podendo durar dezenas de horas). A otimização do processo de pirólise de aerossol proposta nesta tese reduziu este tempo para apenas alguns minutos. Os materiais apresentaram uma área superficial (BET) de até 1028 m2 .g-1 , com volume de poros (BJH) de 0,58 cm3 .g-1 . Os difratogramas de raios-X indicaram um alto grau de organização com um arranjo hexagonal de poros, confirmado também pela microscopia eletrônica de transmissão. Além disto, bandas características de grupos orgânicos não foram observadas nos espectros de absorção na região do infra-vermelho para as amostras obtidas acima de 600ºC. Amostras dopadas com íons Eu3+ também foram preparadas durante a tese. A análise por espectroscopia de luminescência, para íons Eu3+ , indicou que o íon está encapsulado nos canais mesoporosos sem prévia modificação química da matriz. Posteriormente, moléculas de 1,10- Fenantrolina foram coordenadas ao íon Eu3+ aumentando a faixa espectral de excitação do íon (efeito antena). Além disto, partículas luminescentes também foram obtidas pela incorporação do complexo Eu(fod)3 ou rodamina-B nos poros das matrizes. Finalmente, testes de recobrimento (core shell, SiO2 mesoporoso-SiO2) das partículas luminescentes foram realizados e os resultados indicaram que independentemente da espessura obtida pelo processo de recobrimento, o grau de organização dos poros e a fotoluminescência não sofreram alterações
Spherical mesoporous silica particles were obtained using the template synthesis by spray pyrolysis process. The process was optimized for the preparation of the mesoporous materials in one-pot route without organic residues, eliminating thus, the long process of removal of the surfactant, usually used in the available methods (heat treatment or soxhlet extraction, which require several hours or days). The one- pot route proposed in this thesis reduced the extraction process to only a several minutes. These materials presented a surface area value (BET) of 1028m2 .g-1 and pore volume (BJH) was 0,58 cm3 .g-1 . The X-ray diffraction patterns and the transmission electronic micrographs show an ordered typical p6mm 2D hexagonal mesostructure. Characteristics bands of organic groups were not observed in the infra-red absorption spectra for the samples obtained at 600ºC. Moreover, SiO2 mesoporous doped with Eu3+ ions were also prepared. Luminescence data suggest that the Eu3+ ions were successful encapsulated into the channels of mesoporous silica without any preliminary chemical modification of the matrix. Moreover, extra ligands such as 1,10-Phenantroline can be further coordinated, increasing the spectral range excitation (antenna effect). Furthermore, luminescent particles were also prepared by the wet impregnation of Eu(fod)3 complex and rhodamine-B molecules. Finally, tests of coating (core shell, SiO2 mesoporous-SiO2) of luminescent particles had been carried through and the The results obtained show spherical shape and the observation of a highly ordered hexagonal array of mesochannels further confirms the 2D hexagonal p6m structure. Luminescence results reveal that rhodamine-B has been successfully encapsulated into the channels of mesoporous particles. Silica coating has been observed in TEM measurements
4
Bowmar, Paul. "Optical spectroscopy of novel materials." Thesis, University of Oxford, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.259758.
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Williams, Mark. "Uranium(VI) uptake by geological materials, characterisation by luminescence spectroscopy." Thesis, University of Manchester, 2017. https://www.research.manchester.ac.uk/portal/en/theses/uraniumvi-uptake-by-geological-materials-characterisation-by-luminescence-spectroscopy(0220200d-b14b-4ef2-99e0-8d0342701576).html.
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Many of the wastes associated with the nuclear fuel cycle are toxic to the biosphere; advancing the use of high resolution spectroscopy applied to these materials will provide the chemical speciation of the interaction between nuclear waste and geological material, improving confidence in a permanent disposal method and informing clean-up operations. Luminescence spectroscopy of uranyl(VI) is a well-established technique for the molecular speciation of uranium-mineral interactions. This work explores the use of both micro- and macroscopic luminescence spectroscopy to expose uranyl(VI) speciative heterogeneity in a range of minerals which have been exposed to uranyl(VI) salt solutions. A comprehensive review of the available literature on the interaction of uranyl(VI) with a range of geological media is assessed and compared. The review finds considerable ambiguity in the speciation of uranyl(VI) at the mineral water interface. A database reporting the multi parametric luminescence properties of uranyl(VI) with silica gel, quartz, bayerite, boehmite, muscovite, kaolinite and montmorillonite (SWy-2 and STx-1b) is presented and discussed. Although some of the results are consistent with previously reported values, many newly identified species are reported and their identification speculated. Parallel factor analysis is used to deconvolute the excitationemission matrix of uranyl(VI) sorbed to silica gel between pH 3 and pH 10. The results are used to identify the spectroscopic properties of complexes >(SiO)2UO2 and >(SiO)2UO2OH and thus new complexation coefficients (log(K)) for their formation with the silica gel surface are determined, log(K1) = 9.22 ± 0.02 and log(K2) = 3.45 ± 0.01, respectively. The investigation also provides insight into the fundamental properties of uranyl(VI) excitation pathways, which are not yet fully understood. Confocal microscopy and phosphorescent lifetime image mapping (PLIM) is used to expose the sub-micron heterogeneity of uranyl(VI) sorption complexation across mineral surfaces of silica gel, bayerite and montmorillonite (STx-1b). The results suggest that changes in the uranyl(VI) lifetime can be used to observe and understand submicron changes in uranyl(VI) complexation at hitherto unknown temporal resolution.
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Sano, Takeshi. "Charge transport and luminescence control in organic and conjugated materials." Thesis, University of Cambridge, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.620333.
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Alexeev, Evgeny. "Hot-carrier luminescence in graphene." Thesis, University of Exeter, 2015. http://hdl.handle.net/10871/18231.
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In this thesis, the effect of the sample properties on the characteristics of the hot carrier luminescence in graphene is investigated. The present work focuses on the two main issues described below. The first issue is the modification effects of near-infrared pulsed laser excitation on graphene. For excitation fluences several orders of magnitude lower than the optical damage threshold, the interaction with ultrafast laser pulses is found to cause a stable change in the properties of graphene. This photomodification also results in a decrease of the hot photoluminescence intensity. The detailed analysis shows that ultrafast photoexcitation leads to an increase in the local level of hole doping, as well as a change in the mechanical strain. The variation of doping and strain are linked with the enhanced adsorption of atmospheric oxygen caused by the distortion of the graphene surface. These findings demonstrate that ultrashort pulsed excitation can be invasive even if a relatively low laser power is used. Secondly, the variation of the hot photoluminescence intensity with the increasing charge carrier density in graphene is investigated. The electro-optical measurements performed using graphene field-effect transistors show a strong dependence of the photoluminescence intensity on the intrinsic carrier concentration. The emission intensity has a maximum value in undoped graphene and decreases with the increasing doping level. The theoretical calculations performed using a refined two-temperature model suggest that the reduction of the photoluminescence intensity is caused by an increase in the hot carrier relaxation rate. The modification of the carrier relaxation dynamics caused by photoinduced doping is probed directly using the two-pulse correlation measurements. The discovered sensitivity of the hot photoluminescence to the intrinsic carrier concentration can be utilised for spatially-resolved measurements of the Fermi level position in graphene samples, offering an advantage in resolution and speed.
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Chen, Thomas D. (Thomas Duhwa). "Energy transfer and luminescence enhancement in Er-doped silicon." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/9536.
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Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1999.Also issued in pages.
Includes bibliographical references (leaves 143-152).
Er-doped silicon (Si:Er) is a promising light emitting material for silicon microphotonics. A study of Si:Er excitation/de-excitation mechanisms and luminescence enchancement is presented in this thesis. A model based on impurity Auger and nonradiative nmltiphonon transitions (NRl\·IPT) is shown to describe the temperature quenching of the photoluminescence (PL) intensity from 4K to 300K This model asserts that the nonradiative Auger process is mainly responsible for the temperature quenching below lOOK, and NRMPT backtransfer process is mainly responsible for the temperature quenching above lOOK. Junction photocufrei1t · spectmscopy (JPCS) measurements confirmed the existence of a backtransfer mechanism that grows with temperature in accordance to the model. In order to circumvent the onset of nonradiative transitions at higher temperatures, spontaneous emission enhancement in nrnltilayer Si/Si02 microcavities was explored as a means to increase the PL intensity. Because multilayer microcavity structures cannot be constructed using single crystal silicon, Er-doped polysilicon (poly-Si:Er) was developed as a light emitting material for these microcavities. The poly-Si:Er material exhibited a luminescence very similar to that of Er in single crystal silicon. By crystallizing poly-Si:Er from amorphous material and performing a post-anneal hydrogenation, a reasonably high PL intensity, which was limited by the excitation power, was attained. Microacavities with poly-Si:Er were fabricated and measured for the first time. Cavity quality factors of -60-300 were measured, and an Er enhancement of -20x was observed. A -lOx enhancement of a small background emission from the polysilicon was also observed. The observed enhancement factors match well with computed enhancement factors derived from electric field intensity distribution within the microcavity structure. Exploratory work in optical gain from Si:Er waveguides and vertically coupled ring resonntors was conducted. A fiber coupling technique for low temperature waveguide transmission experiments was developed for the gain experiments. The transmission spectrum of a 3-cm long waveguide was measured at temperatures down to 125K. Because the temperature could not be lowered without debonding the fiber, a net gain could not be observed in this particular waveguide. The application of stimulated emission in Si:Er devices is analyzed and discussed.
by Thomas Duhwa Chen.
Ph.D.
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Potter, Mark David George. "Luminescence spectroscopy of CdTe/CdS based photovoltaic devices and associated materials." Thesis, Durham University, 2000. http://etheses.dur.ac.uk/4607/.
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This thesis contains primarily a study of CdTe/CdS heterojunction solar cells^ chiefly using photoluminescence spectroscopy. These solar cells show a good potential for commercial power generation in the near Aiture and are of interest to several major companies. A vital but little understood step in the manufacturing process is: annealing the cells in the presence of chlorine prior to back contact application. Studies are performed on a selection of thin film CdTe/CdS cells subjected to CdCl(_2) anneals of different duration. A chemical bevel etch was used to study the spectra at different depths into the sample and laser intensity arid sarhple temperature variations to identify the mechanisms behind the observed photoluminescence peaks. Evidence was found for the CdCl(_2) anneal promoting sulphur diffusion and subsequent grain boundary passivation in the CdTe, leading to increased minority carrier lifetimes and device efficiencies Attempts to obtain electroluminescence from the CdTe/CdS solar cells were madei By using current pulses electroluminescence was obtained in the 780-850nm range with discernible spectral features. Photoluminescence (PL) studies were also performed on a single crystal of CdTe grown to an unprecedented size of approx. 5 cm diameter at Durham university by a multi-tube seeded vapour method of crystal growth. Much higher resolution spectra were: obtained for this than for the solar cells. Several peaks were identified arid the mechanisms responsible were theorised. By taking slices of the crystal boule the PL spectra at different points-throughout the bulk of the crystal were determined. A series of high quality ion-implanted CdTe crystals were also studied! by intensity and temperature dependent PL in order to obtain a better understanding of the effects of known concentrations of known impurities on the PL spectra of CdTe. Specific PL features associated with certain dopants were observed.
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Balogh, Margareta Cristina. "New luminescent materials, bio-inspired and recyclabe, based on lanthanide complexes." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSEN039.
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L’objectif de ce projet a été de concevoir des matériaux émissifs recyclables à base de lanthanide, en vue de remplacer les oxydes contenus dans les lampes fluoro-compactes (CFLs). Les lanthanides, en particulier l’Eu¹¹¹ et le Tb¹¹¹ ont été les principaux « ingrédients » dans les phosphores à cause de leurs émissions fines dans le rouge et le vert. Les complexes tris-dipicolinate de lanthanides, solubles dans l’eau sont connus pour leurs excellentes propriétés de luminescence, ce qui en fait de bons candidats pour des applications dans le domaine de l’éclairage.Cette thèse décrit l’étude des complexes de tris-dipicolinate d’Eu¹¹¹ et de Tb¹¹¹ sous forme cristalline avec différents contre-cations, ainsi que des systèmes plus complexes comme des co-cristaux ou des de cristaux cœur/coquille. Ces complexes ont également été utilisés comme dopant dans des silices mésostructurées en utilisant une méthode dites de « incipient wet impregnation » (IWI). Les propriétés photophysiques de ces matériaux ont été étudiées en détail et une forte exaltation des propriétés d’émission a été mise en évidence dans les silices. En particulier, l’influence des oscillateurs O-X a été montrée et la détermination du rendement quantique intrinsèque nous a procuré une meilleure compréhension de cette exaltation.La recyclabilité des complexes de lanthanide dans la silice a pu être réalisée avec des bons rendements. Des matériaux, émettant de la lumière blanche ont pu être obtenus en mélangeant des émetteurs rouge, vert et bleu. Le naphtalimide a été choisi comme émetteur bleu. Ainsi, le mélange des complexes d’Eu¹¹¹ et de Tb¹¹¹ et de naphtalimide au sein d’une silice mésoporeuse a conduit à la première génération de matériaux émettant de la lumière blanche et pouvant être facilement recyclésThe objective of this project was to explore recyclable lanthanide based materials suitable for replacing the oxides from compact fluorescent lamps (CFLs). Lanthanides, particularly Eu¹¹¹ and Tb¹¹¹ have been the main “ingredients” in phosphors due to their colour purity and sharp emission in the red and green range of the visible spectrum. Lanthanide tris-dipicolinates are water soluble complexes, known for their excellent photophysical properties which makes them great candidates for lighting. The thesis describes the study of Eu¹¹¹ and Tb¹¹¹ tris-dipicolinate complexes in the crystalline form with different cations, as well as more complex systems like mixed co-crystals and core/shell crystals. The Eu¹¹¹ and Tb¹¹¹ complexes were also used as dopant in mesostructured silica materials via an incipient wetness impregnation method leading to homogeneous materials. The photophysical properties these different materials were thoroughly studied and a significant exaltation of the emission was evidenced in the silica. In particular, the influence of the O-X oscillators was explored and determination of the intrinsec quantum yield gave a clearer image on this exaltation. The recyclability of the lanthanide complexes from the material has been proven with high rates. Finally, white light emitting materials were obtained by mixing red, green and blue emitters. The naphthalimide moiety was chosen as blue emitter and white luminescence was successfully obtained in the solid state and for a silica material, representing a first generation of recyclable white light emitting materials based on lanthanide tris-dipicolinate complexes
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Supran, Geoffrey James Sasajima. "Enhancing quantum-dot luminescence in visible and infrared light emitting devices." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/104112.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2016.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 137-160).
We investigate how the external quantum efficiency (EQE) of colloidal quantum-dot light emitting devices (QD-LEDs) can be enhanced by addressing in situ QD photoluminescence (PL) quenching mechanisms occurring with and without applied bias. QD-LEDs promise efficient, high colour-quality solid-state lighting and displays, and our cost analysis of industrial-scale QD synthesis suggests they can be cost competitive. Efficiency 'roll-off' at high biases is among the most enduring challenges facing all LED technologies today. It stands in the way of high efficiencies at high brightness, yet it has not previously been studied in QD-LEDs. Simultaneous measurements of QD electroluminescence (EL) and PL in an operating device allow us to show for the first time that EQE roll-off in QD-LEDs derives from the QD layer itself, and that it is entirely due to a bias-driven reduction in QD PL quantum yield. Using the quantum confined Stark Effect as a signature of local electric fields in our devices, the bias-dependence of EQE is predicted and found to be in excellent agreement with the roll-off observed. We therefore conclude that electric field-induced QD PL quenching fully accounts for roll-off in our QD-LEDs. To investigate zero-bias PL quenching, we fabricate a novel near-infrared (NIR)-emitting device based on core-shell PbS-CdS QDs synthesised via cation exchange. QDs boast high PL quantum yield at wavelengths beyond 1 [mu]m, making them uniquely suited to NIR applications such as optical telecommunications and computing, bio-medical imaging, and on-chip bio(sensing) and spectroscopy. Core-shell PbS-CdS QDs enhance the peak EQE of core-only PbS control devices by 50- to 100-fold, up to 4.3 %. This is more than double the efficiency of previous NIR QD-LEDs, making it the most efficient thin-film NIR light source reported. PL measurements reveal that the efficiency enhancement is due to passivation of the PbS core by the CdS shell against a non-radiative recombination pathway caused by a neighboring conductive layer within the device architecture.
by Geoffrey James Sasajima Supran.
Ph. D.
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Rocha, Lucas Alonso. "Materiais meso-estruturados luminescentes." Araraquara : [s.n.], 2010. http://hdl.handle.net/11449/105768.
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Orientador: Sidney José Lima RibeiroOrientador: Marc Verelst
Banca: Younès Messaddeq
Banca: Oscar Manoel Loureiro Malta
Banca: Luis Antonio Ferreira Martins Dias Carlos
Banca: Marie-Joëlle Menu
Banca: Jeannette Dexpert-Ghys
Resumo: Partículas esféricas de sílica mesoporosa foram obtidas a partir da síntese "template" pelo processo de pirólise de aerossol. O processo foi otimizado para a obtenção de materiais mesoporosos sem resíduos orgânicos e preparados em uma única etapa, eliminando assim, a longa etapa de remoção do surfactante na metodologia tradicional (tratamento térmico ou extração soxhlet, podendo durar dezenas de horas). A otimização do processo de pirólise de aerossol proposta nesta tese reduziu este tempo para apenas alguns minutos. Os materiais apresentaram uma área superficial (BET) de até 1028 m2 .g-1 , com volume de poros (BJH) de 0,58 cm3 .g-1 . Os difratogramas de raios-X indicaram um alto grau de organização com um arranjo hexagonal de poros, confirmado também pela microscopia eletrônica de transmissão. Além disto, bandas características de grupos orgânicos não foram observadas nos espectros de absorção na região do infra-vermelho para as amostras obtidas acima de 600ºC. Amostras dopadas com íons Eu3+ também foram preparadas durante a tese. A análise por espectroscopia de luminescência, para íons Eu3+ , indicou que o íon está encapsulado nos canais mesoporosos sem prévia modificação química da matriz. Posteriormente, moléculas de 1,10- Fenantrolina foram coordenadas ao íon Eu3+ aumentando a faixa espectral de excitação do íon (efeito antena). Além disto, partículas luminescentes também foram obtidas pela incorporação do complexo Eu(fod)3 ou rodamina-B nos poros das matrizes. Finalmente, testes de recobrimento (core shell, SiO2 mesoporoso-SiO2) das partículas luminescentes foram realizados e os resultados indicaram que independentemente da espessura obtida pelo processo de recobrimento, o grau de organização dos poros e a fotoluminescência não sofreram alterações
Abstract: Spherical mesoporous silica particles were obtained using the template synthesis by spray pyrolysis process. The process was optimized for the preparation of the mesoporous materials in one-pot route without organic residues, eliminating thus, the long process of removal of the surfactant, usually used in the available methods (heat treatment or soxhlet extraction, which require several hours or days). The one- pot route proposed in this thesis reduced the extraction process to only a several minutes. These materials presented a surface area value (BET) of 1028m2 .g-1 and pore volume (BJH) was 0,58 cm3 .g-1 . The X-ray diffraction patterns and the transmission electronic micrographs show an ordered typical p6mm 2D hexagonal mesostructure. Characteristics bands of organic groups were not observed in the infra-red absorption spectra for the samples obtained at 600ºC. Moreover, SiO2 mesoporous doped with Eu3+ ions were also prepared. Luminescence data suggest that the Eu3+ ions were successful encapsulated into the channels of mesoporous silica without any preliminary chemical modification of the matrix. Moreover, extra ligands such as 1,10-Phenantroline can be further coordinated, increasing the spectral range excitation (antenna effect). Furthermore, luminescent particles were also prepared by the wet impregnation of Eu(fod)3 complex and rhodamine-B molecules. Finally, tests of coating (core shell, SiO2 mesoporous-SiO2) of luminescent particles had been carried through and the The results obtained show spherical shape and the observation of a highly ordered hexagonal array of mesochannels further confirms the 2D hexagonal p6m structure. Luminescence results reveal that rhodamine-B has been successfully encapsulated into the channels of mesoporous particles. Silica coating has been observed in TEM measurements
Doutor
13
Savchuk, Oleksandr. "Development of new materials and techniques for luminescence nanothermometry and photothermal conversion." Doctoral thesis, Universitat Rovira i Virgili, 2016. http://hdl.handle.net/10803/384226.
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Hem estudiat la dependència amb la temperatura de la luminescència generada per nanopartícules dielèctriques dopades amb ions lantànids que poden ser utilitzades en nanotermometria luminescent. Hem analitzat nous materials amb emissió en el rang del visible de l’espectre electromagnètic, incloent Ho,Yb:KLu(WO4)2 i Ho,Tm,Yb:KLu(WO4)2, així com nanopartícules core-shell de Er,Yb:GdVO4@SiO2. També hem desenvolupat un nou mètode de síntesi solvotermal assistit per microones per nanopartícules de Er,Yb:NaYF4, que opera a temperatures més baixes i temps de reacció més curts que els mètodes convencionals. Hem utilitzat nanotermometria basada en la mesura dels temps de vida mitjana radiativa en nanopartícules up-conversores de Er,Yb:NaY2F5O per la determinació de temperatura en sistemes biològics, així com la determinació de temperatura pel canvi de color de l’emissió de nanopartícules de Tm,Yb:GdVO4@SiO2. Finalment, hem desenvolupat un sistema de nanotermometria luminescent simple i compacte que permetrà atansar la nanotermometria luminescent a l’entorn mèdic i industrial. Hem analitzat també la nanotermometria luminescent en la regió de l’infraroig proper. El Nd:KGd(WO4)2 mostra potencial com nanotermòmetre luminescent en aquesta regió per sistemes biològics, amb una profunditat de penetració d’1 cm en teixits biològics. Els ions Er3+ i Tm3+ mostren bandes d’emissió eficients en aquesta regió que poden utilitzar-se per nanotermometria luminescent en sistemes biològics. Les nanopartícules de Tm,Yb:GdVO4@SiO2, amb emissions localitzades en la primera finestra biològica, presenten una elevada sensitivitat tèrmica i s’han internalitzat en cèl·lules HeLa. Finalment, hem mostrat la multifuncionalitat de les nanopartícules de Ho,Tm:KLu(WO4)2 que actuen com nanotermòmetres, agents fototèrmics i marcadors biològics. També hem determinat l’eficiència de conversió fototèrmica del grafè i derivats, escalfadors eficients pel tractament de diverses malalties inclòs el càncer, i hem desenvolupat un nou mètode per determinar aquesta eficiència de conversió utilitzant una esfera integradora, un mètode que es pot estendre a altres agents fototèrmics.Hemos estudiado la dependencia con la temperatura de la luminiscencia generada por nanopartículas dieléctricas dopadas con iones lantánido que pueden ser usadas en nanotermometría luminiscente. Hemos analizado nuevos materiales con emisión en el rango del visible del espectro electromagnético, incluyendo Ho,Yb:KLu(WO4)2 y Ho,Tm,Yb:KLu(WO4)2, así como nanopartículas core-shell de Er,Yb:GdVO4@SiO2. También hemos desarrollado un nuevo método de síntesis solvotermal asistido por microondas para nanopartículas de Er,Yb:NaYF4, que opera a temperaturas más bajas y tiempos de reacción más cortos que los métodos convencionales. Hemos utilizado nanotermometría basada en la medida de tiempos de vida media radiativa en nanoparticulas up-conversoras de Er,Yb:NaY2F5O para la determinación de temperatura en sistemas biológicos, así como la determinación de temperatura por el cambio de color de la emisión de nanopartículas de Tm,Yb:GdVO4@SiO2. Finalmente, hemos desarrollado un sistema de nanotermometría luminiscente simple y compacto que va a permitir acercar la nanotermometría luminiscente al entorno médico e industrial. Hemos analizado también la nanotermometría luminiscente en la región del infrarojo cercano. El Nd:KGd(WO4)2 muestra potencial como nanotermómetro luminiscentes en esta región para sistemas biológicos, con una profundidad de penetración de 1 cm en tejidos biológicos. Los iones Er3+ y Tm3+ muestran bandas de emisión eficientes en esta región que pueden utilizarse para nanotermometría luminiscente en sistemas biológicos. Las nanopartículas de Tm,Yb:GdVO4@SiO2, con emisiones localizadas en la primera ventana biológica, presentan una elevada sensitividad térmica y se han internalizado en células HeLa. Finalmente, hemos mostrado la multifuncionalidad de las nanopartículas de Ho,Tm:KLu(WO4)2 que actúan como nanotermómetros, agentes fototérmicos y marcadores biológicos. También hemos determinado la eficiencia de conversión fototérmica del grafeno y derivados, calentadores eficientes para el tratamiento de diversas enfermedades incluido el cáncer, y hemos desarrollado un nuevo método para determinar esta eficiencia de conversión utilizando una esfera integradora, un método que puede extenderse a otros agentes fototérmicos.
We studied the temperature dependence of the luminescence generated by dielectric nanoparticles doped with lanthanide ions to be used in luminescence nanothermometry. New materials emitting in the visible range of the electromagnetic spectrum, including Ho,Yb:KLu(WO4)2 and Ho,Tm,Yb:KLu(WO4)2 and Er,Yb:GdVO4@SiO2 core-shell nanoparticles have been analyzed for these purposes. Moreover, we developed a new and greener microwave-assisted solvothermal synthesis method for Er,Yb:NaYF4 nanoparticles that operates at lower temperatures and shorter reaction times than conventional methods. We used lifetime-based nanothermometry in upconversion Er,Yb:NaY2F5O nanoparticles for temperature determination in biological systems, and the change of color of the emission generated in Tm,Yb:GdVO4@SiO2 core-shell nanoparticles as a function of temperature. Furthermore, we developed a simple and compact setup that would approach luminescence nanothermometry to the real practical applications in medical and industrial environments. We also explored luminescence nanothermometry in the near infrared region of the electromagnetic spectrum. Nd3+-doped KGd(WO4)2 nanoparticles show potentiality as a luminescent nanothermometer in this region for biological systems, with a penetration depth of 1 cm in biological tissues. Er3+ and Tm3+ ions doped in different matrices have shown also efficient emission bands lying in the short-wavelength infrared region that can be used for luminescence thermometry in biological systems. Also, Tm3+,Yb3+:GdVO4@SiO2 core-shell nanoparticles with emissions located in the first biological window are presented as highly thermal sensitive nanothermometers and have been efficiently internalized in the HeLa cells. Finally, the multifunctionality of Ho3+ and Tm3+ co-doped KLu(WO4)2 nanoparticles has been shown, acting as nanothermometers, photothermal agents and biolabels for bioimaging. Also, we determined the photothermal conversion efficiency of graphene and graphene oxide, efficient heaters for the treatment of several diseases including cancer, and developed a new method for determining their photothermal conversion efficiency by using an integrating sphere, a method that can be extended to other photothermal agents.
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White, D. R. R. "Spectral luminescence studies of rare earth doped CaF2 and some synthetic materials." Thesis, University of Sussex, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.283110.
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Behrh, Gaganpreet Kaur. "Synthesis and characterization of inorganic luminescent materials." Thesis, Nantes, 2017. http://www.theses.fr/2017NANT4037/document.
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L'objectif de la thèse est de synthétiser et de caractériser les matériaux photoluminescents qui présentent de la luminescence extrinsèque et intrinsèque. Pour les matériaux luminescents extrinsèques, l'objectif était de régler la couleur d'émission de terres rares par deux méthodes: la méthode conventionnelle du dopage / codopage par un ion de terre rare et une nouvelle méthode appelée la réduction contrôlée des dopants. Le dopage a été effectué pour les ions tels que Eu2+, Eu3+ dopés dans la matrice M2Ga2SiO7 (M: Sr, Ca). Mais une telle méthode présente des inconvénients, à savoir pour réaliser le contrôle de la couleur d'émission qui nécessite soit un changement du réseau hôte pour le dopage, soit le dopage par au moins deux ions de terres rares. Ainsi, une nouvelle technique appelée réduction contrôlée de dopants a été mis en oeuvre, où la couleur d'émission est provient d’un contrôle précis du rapport Eu3+/Eu2+. Cette approche a été illustrée par la réduction progressive du matériau SrAl2O4: Eu3+ qui passe d’un luminescence rouge à une luminescente verte, en passant par le jaune selon le rapport Eu3+/Eu2+. L'autre partie de la thèse est axée sur la luminescence intrinsèque de certains qui provient de la présence de défauts intrinsèques. Le composé stannate tels que Mg2SnO4 a été utilisé comme un exemple pour illustrer ce genre de luminescence intrinsèque. Ce matériau présente une autre caractéristique intéressante puisqu’il phosphoresce dans le blanc tout en ayant une luminescence dans l’IRThe objective of the thesis is to synthesize and characterize the photoluminescent materials which exhibit extrinsic and intrinsic luminescence. For extrinsic luminescent materials, the objective was to tune the emission color of such rare earth doped materials via two methods: the conventional method Doping/Codoping by a rare earth ion and a new method called Controlled Reduction of Dopants. Doping was carried out for the rare earth ions such as Eu2+, Eu3+ doped gallates M2Ga2SiO7 (M:Sr,Ca) phases. But such method have drawbacks i.e. to achieve the control over the emission color either a change of the host lattice is required for doping or minimum of two rare earth ions are required for codoping. So a new technique called Controlled Reduction of Dopants was setup, where the emission color is tuned on the basis of the change of the oxidation state of the rare earth ion doped in the phase. This approach was illustrated with the progressive reduction of the red phosphor SrAl2O4:Eu3+ to green phosphor SrAl2O4:Eu2+ to target yellow luminescence. The other part of the thesis is focused upon self activated or intrinsic luminescent materials which show luminescence due to the intrinsic defects present in them. Stannates such as Mg2SnO4 was used as an example to illustrate this kind of intrinsic luminescence. This material exhibits another interesting character of exhibiting the both white long lasting luminescence and IR luminescence
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Malba, Chandrashekhar Marotirao <1982>. "Synthesis and characterization of lanthanide based luminescent materials." Doctoral thesis, Università Ca' Foscari Venezia, 2013. http://hdl.handle.net/10579/3071.
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In this thesis, synthesis and characterization of new lanthanide based luminescent hybrid materials is studied. The thesis consists of two parts. The silica based luminescent hybrid nanomaterials have been prepared and studied in the first part. The different ways for the nanoencapsulation of rare earth complexes in mesoporous silica nanoparticles have been used to prepare highly luminescent nanomaterials. A highly luminescent Eu(Tp)3 complex with limited solubility in organic solvents has been synthesized in situ inside the pores of presynthesized mesoporous silica nanoparticles. The effect of different chemical environment in the silylated mesoporous silica nanoparticles on the luminescence properties of the Eu(III) complex has been studied in detail by encapsulating Eu(dbm)3phen complex in the pores of organically modified mesoporous silica nanoparticles. Furthermore, solid state NMR studies were performed on the Y(dbm)3phen encapsulated mesoporous silica nanoparticles to obtain the structural and dynamic information on these materials. Co-luminescence effect of Tb(III) and Eu(III) complexes has been studied in the mesoporous silica matrix, with the aim of improving luminescence properties of the encapsulated Eu(III) complex. In the second part of this PhD thesis, new anionic tetrakis lanthanide complexes have been synthesized, characterized and their luminescence properties have been studied in detail in the solid state. Furthermore, the luminescent soft materials were prepared by dissolving anionic tetrakis lanthanide complexes in the phosphonium ionic liquids. The phosphonium ionic liquids have been explored as spectroscopic solvents for studying luminescence of new tetrakis lanthanide complexes.In questa tesi e’ stata condotto uno studio che ha riguardato la sintesi e la caratterizzazione di nuovi materiali ibridi luminescenti a base di lantanidi. La tesi si compone di due parti. Nella prima parte sono stati preparati e studiati dei nanomateriali ibridi luminescenti a base di silice. Sono state utilizzate diverse modalita’ per il nanoincapsulamento di complessi di terre rare in nanoparticelle di silice mesoporose per preparare nanomateriali altamente luminescenti. Il complesso luminescente Eu(Tp)3, che genralmente mostra una limitata solubilità in solventi organici, è stato sintetizzato in situ all'interno dei pori delle nanoparticelle di silice mesoporose pre-sintetizzate. E’ stato inoltre studiato in dettaglio l’effetto di diverse funzionalizzazioni di nanoparticelle di silice mesoporosa sulle proprietà luminescenti del complesso Eu(dbm)3phen tramite il suo incapsulamento nei pori modificati sulla superficie delle nanoparticelle di silice mesoporose. Per ottenere le informazioni strutturali e dinamiche su questo tipo di sistemi si sono condotti anche degli studi NMR, allo stato solido, su nanoparticelle di silice mesoporose con il complesso Y(dbm)3phen incapsulato. L’effetto di columinescenza dei complessi di Tb(III) e Eu(III) è stato studiato in matrice di silice mesoporosa, allo scopo di migliorare le proprietà di luminescenza del complesso di Eu(III) incapsulato in essa. Nella seconda parte di questa tesi di dottorato, sono stati inoltre sintetizzati e caratterizzati nuovi complessi anionici tetrakis conteneti elementi lantanoidi allo stato solido, e sono state studiate in dettaglio le loro proprietà luminescenti. Infine, sono stati preparati materiali luminescenti “soffici” sciogliendo complessi anionici tetrakis conteneti elementi lantanoidi in liquidi ionici a base di fosfonio e sono state studiate le proprità luminescenti relative.
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De, Silva Mawanana H. Channa R. "Lanthanide-containing Functional Materials: Exploratory Synthesis and Property Investigation." Diss., The University of Arizona, 2007. http://hdl.handle.net/10150/195622.
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The research summarized in this dissertation is aimed at the design and exploratory synthesis, characterization, and property investigation of lanthanide-based functional materials. The substances prepared in this work, including small molecular complexes and nanostructured particles, are of fundamental scientific interest as well as practical significance due to the unique chemical and physical properties of the lanthanide elements. Envisioned applications include their uses as light-emitting materials in modern display technology, optical amplifiers, and high-density magnetic recording media. This research seeks to develop general methods for directing the formation of lanthanide materials, particularly as a means of influencing the physical properties of such materials. These efforts are elaborated in distinct yet related projects.In Chapter 2, exploratory synthesis, structural characterization, and photo-physical investigation of adducts of lanthanide β-diketonates with a tridentate neutral ligand, TPTZ are described.In Chapter 3, analogous studies utilizing p,p'-disubstituted bipyridine and phenathroline type bidentate neutral ligands are detailed. The structures of the complexes have been established by single crystal X-ray diffraction. Compositional and structural differences among the various complexes are caused by different structural and electronic properties of the ligands and overall steric compactness of the coordination sphere. Red and green luminescence characteristics of Eu(III) and Tb(III) ions are observed for the corresponding complexes, upon UV excitation, consistent with the well-established ligand-mediated energy transfer and light emission mechanism.In Chapter 4, the electroluminescence properties of various europium complexes are evaluated for their potential as emissive materials in organic light-emitting diodes.The synthesis and characterization of Er-doped LaPO4 nanoparticles are described in Chapter 5 together with the preparation and studies of hybrid nanocomposites composed of nanoparticle-doped sol-gels. A single-mode waveguide system was fabricated, wherein Er-doped nanoparticles solubilized in a sol-gel matrix has shown promising performance in propagating light signals (1.54 µm) without significant optical losses.In Chapter 6, synthesis, electron microscopic characterization and magnetic studies of crystalline Sm(III)- and Eu(III)-doped Fe3O4 nanoparticles are detailed. Magnetic studies suggest the ferromagnetic behavior of the lanthanide-doped Fe3O4 nanoparticles at room temperature and therefore, the significant effects of lanthanide doping.
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Mukherjee, Kunal Ph D. Massachusetts Institute of Technology. "Lattice-mismatched epitaxy of AlInP and characterization of its microstructure and luminescence." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/112386.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2014.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 178-183).
The synthesis of high-quality III-V ternary alloy semiconductors is vital to the success of major technologies such as LEDs, laser diodes, high-efficiency solar cells and power electronics. However, the epitaxy of ternary alloys can be complicated due to the dissimilar behavior of constituent atoms on the growth surface. Historically, lattice matching of the ternary alloy to a substrate is another important constraint that limits access to all but a few alloy fractions. A technologically important ternary alloy in which both surface kinetics and lattice matching is crucial is the wide band-gap AlxIn1-xP system. This alloy is commercially used at one specific composition, a random solid solution of Al0.5In0.5P lattice-matched to GaAs, as a high indirect band-gap cladding/barrier layer for the ubiquitous red LEDs and laser diodes. Little is known about AlxIn1-xP at other compositions and with non-random microstructures despite the potential benefit of gaining access to the highest direct band-gap semiconductor amongst all non-nitride III-V semiconductors. In this thesis, InyGa1-yAs compositionally graded buffers are used to bridge lattice mismatch, leading to the synthesis of AlxIn1-xP at a range of compositions with low threading dislocation densities (105-06/cm2) and low oxygen levels (2x1016/cm3). The high-quality of these films result in the first report of room-temperature yellow-green luminescence from AlxIn1-xP comparable in brightness to lattice-matched films. An accurate band-gap vs composition map of the AlxIn1-xP alloy space is created with Al0.43In0.57P identified as having the highest direct band-gap of 2.33 eV. The formation of non-random microstructures in AlxIn1-xP due to phase separation and atomic ordering is studied in detail. Phase separation into aluminum-rich and indium-rich domains is found to evolve from random compositional perturbations via a positive-feedback process limited by aluminum surface-diffusion. A reduction in band-gap by more than 200 meV is obtained by converting a random microstructure to a non-random one using growth temperature. Random/non-random interfaces are designed to use this large band-gap change to improve the efficiency of the first double-heterostructure yellow-green and amber AlxIn1-xP LEDs. Finally, we observe and explain how strain fields from an inhomogeneous distribution of misfit dislocations result in surface roughness and composition fluctuations in lattice-mismatched AlxIn1-xP LEDs. The results obtained in this work will be useful not only in providing control over nanometer-scale structures but also over wafer-scale features. This is crucial in transitioning novel lattice-mismatched devices from the lab to the marketplace.
by Kunal Mukherjee.
Ph. D.
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Huitorel, Brendan. "Matériaux photoluminescents multifonctionnels à base de clusters d’iodure de cuivre." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLX061/document.
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Depuis quelques années, les matériaux luminescents mécanochromiques présentant un changement réversible de leur longueur d'onde d'émission en réponse à un stimulus mécanique externe, suscitent un grand intérêt en raison de leurs applications potentielles pour les mémoires optiques ou les capteurs de pression par exemple. En effet, au cours des cinq dernières années, le nombre de composés luminescents sensibles à la pression rapportés dans la littérature a explosé avec des exemples basés principalement sur des molécules organiques. Comparativement, l’étude de complexes de métaux de transition reste relativement limitée et sont majoritairement des complexes d'or et de platine. Les travaux de recherches menés concernent l’étude des propriétés de mécanochromisme de luminescence de clusters moléculaires d'iodure de cuivre. Après broyage mécanique, leurs propriétés de photoémission sont grandement modifiées. De plus, ces composés ont la particularité de présenter à la fois des propriétés de mécanochromisme et de thermochromisme de luminescenceIn the last years, mechanochromic luminescent materials which exhibit reversible modification of the emission wavelength in response to external mechanical stimuli have attracted great attention because of their potential applications in optical memory devices, pressure sensing systems, for instance. Indeed, due to their promising development, the number of reported pressure sensitive luminescent compounds has exploded in the five last years with examples based mainly on organic dyes. Examples of transition-metal complexes are comparatively limited and essentially based on gold and platinum metals. The developed research concern the study of the mechanochromic luminescent properties of molecular copper iodide clusters. Upon mechanical grinding, their photoemission properties are greatly modified. These compounds have the particularity of exhibiting both mechanochromic and thermochromic luminescence properties
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Fan, Jia. "Concentration quenching mechanism in doped OLED materials." HKBU Institutional Repository, 2007. http://repository.hkbu.edu.hk/etd_ra/829.
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Castaing, Victor. "Recherche de nouvelles couleurs et morphologies dans les matériaux à luminescence persistante." Electronic Thesis or Diss., Paris Sciences et Lettres (ComUE), 2019. http://www.theses.fr/2019PSLEC030.
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La luminescence persistante est la propriété qu’ont certains matériaux de stocker une énergie lumineuse incidente (généralement UV) sous forme d’électrons et (ou) de trous électroniques piégés par des défauts, et de restituer cette énergie sous forme de lumière visible ou proche infra-rouge pendant plusieurs heures. Le mécanisme à l’origine de ce phénomène est cependant toujours mal compris. Le projet de cette thèse a pour objectif d’élucider ce mécanisme en étudiant différents types de matériaux à luminescence persistante et de profiter de cette propriété dans un nouveau champ d’activités : les applications extérieures (lors d’une charge par le soleil par exemple), ou le passage aux nouvelles lampes d’éclairage ne contenant plus d’UV (LED blanches). Le doctorant étudiera deux types de matrices : i) Des céramiques transparentes dans lesquelles sont précipitées des nanoparticules de matériaux à luminescence persistante. Il sera ainsi possible d’étudier les phénomènes (excitation, piégeage, émission) en excitant optiquement (sous rayonnement visible) en suivant in situ l’évolution des spectres en spectrométries RPE et optiques. Cette partie du travail de thèse sera effectué à l’IRCP à Paris en collaboration avec le groupe de Didier Gourier (IRCP), et en collaboration avec le CEMHTI d’Orléans (Mathieu Allix). ii) Des cristaux persistants. Dans ce cas il s’agit de mettre en évidence et de caractériser ce phénomène sur différents monocristaux afin de disposer de cristaux persistants dans une large gamme de couleur. Dans les deux cas, le mécanisme sera étudié dans une approche multi-échelle allant du matériau massif aux nanoparticulesPersistant luminescence is the property of some materials to store energy of light (basically UV). This energy is stored as electrons and (or) holes traped by defects. This materials may also be able to give back this energy as visible light or near infrared during some hours. The mecanism involved in this phenomena is still poorly understood. The aim of this PhD project is to clarify this mecanism by studying diferent kinds of persistant luminescence materials and to try this property in a new application field: outdoor applications (sunlight charging) or to able this materials to be excited by non-containing UV lamps (white LEDs). Therefore, it's necessary to learn more about the "charging" process. The PhD student will study to kinds of matrix: i) Transparent ceramics in which nanocristals of persistant luminescence materials will be precipitated. Excitation, trapping and emission phenomena will be studied by optical spectroscopies and EPR after optical excitation. This work will be done at the IRCP in collaboration with Didier Gourier's group (IRCP) and Mathieu Allix (CEMHTI, Orléans). ii) Persistant cristals. Here the student will show and caracterise this phenomena on diferent monocristals in order to get persistant cristals that emit in a wide range of colors. In both cases, the mecanism will be studied from the bulk material to nanoparticles
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Atoini, Youssef. "New luminescent hybrid materials : synthesis and properties." Thesis, Strasbourg, 2017. http://www.theses.fr/2017STRAF004/document.
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L'objectif de cette thèse est la synthèse, la caractérisation et l'étude de complexes métalliquesluminescents, en particulier de Pt (II), leurs propriétés d'agrégation en solution, mais également dansun espace confiné ainsi qu’en surface. L'incorporation de complexes de métaux de transition dans lastructure poreuse, et ainsi que leur dépôt à la surface de nanoparticules et dans un cadre métalloorganique(MOF), par greffage post-synthétique, ont été étudiés. Sont également étudiés lacorrélation entre les propriétés de films d’une série de complexes de Pt(II) avec leur morphologie,leur mobilité électronique et la simulation de leur structure auto-assemblée par diffraction auxrayons-X. Les propriétés de luminescence de complexes amphiphiles de Pt(II) sont améliorées àl’intérieur de nanoparticules de silice mesoporeuse par la création d’un d’espace confiné. Un effetsimilaire est observé par le dépôt de complexes de Pt(II) fonctionnalisés sur une surface denanoparticules d’or. La luminescence d’un cadre organométallique a été modifiée par greffage postsynthétiquede complexes d’Ir(III) et de Pt(II)The aim of this thesis is the synthesis, characterization and investigation of luminescent metalcomplexes, and in particular of Pt(II) compounds, their aggregation properties in solution but inconfined space as well. The incorporation of transition metal complexes in porous structure, and inparticular in a metal-organic framework (MOF), by post-synthesis grafting, have been investigated.Luminescence properties of amphiphilic Pt(II) complexes were enhanced inside mesoporous silicananoparticles by the creation of a confined space. Similar effect is observed by deposition offunctionalized Pt(II) complexes on gold nanoparticles surface. Luminescence of metal organicframework was tuned by post-synthetic grafting of Ir(III) and Pt(II) complexes
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Chen, Kevin M. (Kevin Ming) 1974. "Electrical breakdown and luminescence from erbium oxide and Er-doped silicon thin films." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/9816.
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Kouroukla, Eftychia. "Luminescence dosimetry with ceramic materials for application to radiological emergencies and other incidents." Thesis, Durham University, 2015. http://etheses.dur.ac.uk/11362/.
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The likelihood of the occurrence of radiological accidents which can induce significant health consequences to the members of the public has raised the importance of developing a personal radiation dosimetry system applicable to populations not monitored by dedicated dosemeters. Mobile phones are personal devices with high ubiquity and great potential for accident dosimetry applications. Alumina surface mount resistors (SMRs) are abundant in the printed circuit board of mobile phones and their potential as fortuitous dosemeters has been investigated using thermoluminescence (TL) and optically stimulated luminescence (OSL) techniques. The physical mechanism of the generation of luminescence of the alumina SMRs is, however, less known. The basic luminescence defects in SMRs were identified to be F-type centres and their emission process was shown to be temperature dependent and highly quenched at room temperature (RT). The trap environment of beta irradiated SMRs includes a series of closely spaced traps covering thermal depths between 0.9-1.4 eV; predicting an average lifetime for thermal fading at RT of ca 23 years. Trapped charges evicted by thermal or optical stimulation are likely to recombine at F-type centres and contribute to the luminescence response that is likely to be thermally assisted via the vibrational modes of the lattice. A phonon-assisted de-excitation of the trapped charge population could additionally be involved in the mechanism of athermal or anomalous fading. Based on the temperature dependence of the rate of fading, a model is presented for the anomalous fading observed where phonon-assisted and tunnelling effects alternate or operate simultaneously depending on the temperature of the material. A number of aspects related to the use of SMRs in dosimetry seem to benefit from the investigation of the physical processes, although for accurate dose reconstruction it is imperative to know the energy of the ionising radiation source and the position of the mobile phone relative to the direction of the source. For example, at low-energy exposures the dose may be over-estimated, not only due to the non-flat energy response of the alumina, but also due to the presence of several parts of the mobile phone which can increase the amount of energy deposited in alumina substrates due to backscatter effects. In addition, MCNP simulations indicated that for low-energy exposures, such as for 192Ir, differences of up to an order-of-magnitude between resistor and whole body dose are expected. Finally, to specify the most appropriate dose conversion coefficients that can be applied to estimate whole body dose from OSL / TL determinations, the knowledge of the exposure geometry is crucial.
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Seiferth, Frederick J. "Light emission from silicon /." Online version of thesis, 1994. http://hdl.handle.net/1850/11444.
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Coyle, Lisa M. "Lifetime measurements on pressure sensitive paints : temperature correction, effects of environment, and trials on new luminescent materials /." Thesis, Connect to this title online; UW restricted, 1999. http://hdl.handle.net/1773/8698.
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Katelnikovas, 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.
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The modern society relies heavily on mankind’s ability to produce light to lengthen the day. Throughout the evolution of artificial lighting lots of light sources were discovered / invented, i.e. burning wood, oil, candles, using incandescent bulbs and fluorescent lamps and, finally, white LEDs. LEDs are superior to other light sources due to their high efficiency. Replacement of conventional light sources by white LEDs what would allow saving huge amounts of electricity consumed for lighting purposes. The main goal of this dissertation was development and investigation of various new materials that could be used in solid state light sources based on near-UV and blue LEDs. One silicate, one molybdate and three garnet structure compounds were selected. Several synthesis methods, i.e. solid state, sol-gel, and sol-gel combustion, were applied in preparation of selected host materials. The host materials were activated by Eu2+, Eu3+, and Ce3+ ions. The phase purity of synthesized samples was evaluated by recording powder XRD patterns. Luminescent properties of the activator ions were investigated by recording reflectance, excitation, emission spectra and decay curves at room temperature. The temperature dependent decay curves and emission spectra were recorded in the range of 77-500 K. Moreover, quantum yields, luminous efficacies and colour points were calculated from the obtained data.Žmonija 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.
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Spencer, Joel Quintus. "The development of luminescence methods to measure thermal exposure in lithic and ceramic materials." Thesis, University of Glasgow, 1996. http://theses.gla.ac.uk/3557/.
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Thermometric analyses provide extremely useful information about heated archaeological materials and fire-damaged modern structures. A number of non-luminescence thermometry methods have been developed for analysing pottery firing temperatures. However, many of these methods are limited in analysis range and accuracy, or are time consuming, expensive and complex. In addition to these techniques there are a number of thermoluminescence (TL) thermometry methods but they are also limited in analysis range and the majority have been developed for specific thermometry problems. The aim of this study was to investigate the use of thermoluminescence (TL) and photostimulated luminescence (PSL) methods to develop rapid, precise, inexpensive thermometry techniques that were applicable to a wide range of thermal events and materials from archaeological and modern contexts. A basic theoretical treatment of luminescence kinetics in silicate systems was undertaken to develop an understanding of TL glow curve alterations arising from thermal exposure. Kinetic studies showed that a combination of temperature and duration parameters is expected for single trap systems. Kinetic theory was developed to produce a new first order multi-trap system which provides a theoretical means of separating temperature and time components, which may be applicable to synthetic phosphors. Additionally heat transfer solutions were investigated to examine the temperature distribution in heated solids and TL instrumentation. Isothermal annealing experiments on IAEA-F-1 potassium feldspar showed a highly precise progressive thermal exposure monitor, whereby the position of the first rise of an annealed TL glow curve is characterised by a linear increase in temperature and a logarithmic increase in time. First order kinetic simulations and initial rise measurements demonstrated a continuous linear distribution of traps in IAEA-F-1 feldspar. Using a high temperature TL system (maximum temperature 700°C) the progressive thermometry method was successfully applied to separated feldspar minerals and polymineral samples from archaeological (ceramics, burnt stones and hearthstones) and modern (fire damaged concrete) materials. PSL excitation spectroscopy showed potential thermometric behaviour but for some samples the sensitivity of the system was too low. Pulsed infra-red PSL showed there may be a limited trap distribution over which a small range of thermal exposures will operate. Combined TL/PSL measurements showed it may be possible to deconvolute temperature and time parameters.
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RIGODANZA, FRANCESCO. "Photoluminescent materials: from organic molecules to nanomaterials." Doctoral thesis, Università degli Studi di Trieste, 2018. http://hdl.handle.net/11368/2918473.
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The research has been focused on tailoring novel photosensitizers, ranging from organic molecules to carbon nanostructure, such as perylene bisimides (PBIs) and carbon nanodots (CNDs): At first it was developed a fast and efficient protocol for the microwave assisted synthesis of perylene bisimides. Imidation reactions of the perylenebisanhydride were performed using a large variety of amines, such as alkylamines, amino alcohols, heteroarylamines, and amino acids. With the powerful tool we developed, we targeted more complex applications. We designed a novel photocatalytic system mimicking the PSII oxygen evolving center. Our approach was based on the unprecedented combination of metal-free perylene bisimides (PBI) as photosensitizers with totally inorganic polyoxometalates (POMs) as catalysts. Oxygen evolution was observed with well-behaved kinetics, long operation time (> 8h), and conversion yields up to >98%. Moreover, we proposed comprehensive structural picture of a perylenebisimide hydrogel, suggesting that its long-range conductivity is limited by charge-transfer between electronic backbones. We revealed nano-crystalline ribbons as the electronic and structural backbone between which charge transfer was mediated by polar solvent bridges. We exemplified this effect with gas sensing, where exposure to polar vapor changes conductivity by five orders of magnitude, emphasizing the crucial role of the interplay between structural motif and surrounding medium for the rational design of devices based on nano-crystalline hydrogels. Jumping to carbon nanostructure we were interested into mastering optical, electronical and structural properties of carbon dots. Thus, we synthesized and characterized green emissive CNDs using organic chromophores, such as boron-dipyrromethenes, as starting materials and we exploited them as tracker in NK cells. Notably, it was optimized a synthetic protocol for the green emissive CNDs that can be extended for the preparation of a library of multicolored CNDs. Furthermore, we prepared and characterized a redox library of CNDs with tunable energy levels by adding to the reaction mixture commercially available quinones and employing a bottom-up MW-assisted hydrothermal treatment. Benzoquinone-, naphthoquinone- and anthraquinone-based carbon nanodots exhibited interesting electrochemistry with oxidation potentials between 1..48 V and 0.98 V vs SCE and reducing one in the range -1.52 V and -2.05 V vs SCE. Finally, we reported the structural and optical modifications happening during the reaction. We identified the core-shell structure of these carbon dots and synthesized novel CNDs with controlling the size of the soft shell that we believe it is the responsible for the optical properties that characterize these interesting nanoparticles.
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Chavoutier, Marie. "Cristallogenèse, caractérisation spectroscopique et potentialité laser de borates et d’oxyborates de terre rare dopés ytterbium." Thesis, Bordeaux 1, 2010. http://www.theses.fr/2010BOR14091/document.
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Facilement excitable au moyen de diode InGaAs, l’ion Ytterbium trivalent présenteune émission infrarouge intéressante pour des applications laser. Les matériaux étudiés sontnombreux. Parmi eux, les borates sont des composés stables, transparents dans l’UV et présentant un seuil élevé au dommage. Ils sont par conséquent des bons candidats pour desapplications optiques. D’un point de vue structural, ils présentent une diversité de sitesd’accueil pour la terre rare ce qui permet de moduler les émissions obtenues en fonction de lacomposition.Nous avons mené une étude d’élaboration et de caractérisation sur un borate (à fusioncongruente) et deux oxyborates (à fusion non congruente) de composition : Li6Ln(BO3)3 ;LiGd6O5(BO3)3 ; Na3La9O3(BO3)8.Les différentes croissances cristallines, par la méthode Czochralski ou par la méthodedu flux, nous ont permis d’obtenir des cristaux de taille centimétrique comportant de largeszones transparentes, utiles pour les tests en cavité laser. L’étude spectroscopique de l’ionytterbium nous a permis d’évaluer l’éclatement des niveaux d’énergie et de localiser les ionsterres rares dans ces matrices. Différentes caractérisations thermiques, mécaniques et optiquesont aussi été réalisées sur les cristaux afin de pouvoir estimer les paramètres laser.Finalement, de premiers tests lasers ont été réalisés et ont montré la potentialité de cesmatériaux en tant que matériaux amplificateursBy the mean of InGaAs diode, trivalent ytterbium ions can give rise to an interestinginfrared emission for laser applications. Numerous compounds are in study. Among them,borates are stable, UV-transparent compounds and they have a high damage threshold. Thusthey are good candidates for optical applications. From a structural point of view, they exhibita diversity of host sites for the rare earth which allows to modulate emission withcomposition.We carry out an elaboration and characterization study on a borate and two oxyboratecompounds of formula Li6Ln(BO3)3 ; LiGd6O5(BO3)3 ; Na3La9O3(BO3)8.Crystal growth, by Czochralski or flux method depending on the meltingcharacteristic, enable us to obtain centimetric sized crystals with large transparent areas.Ytterbium ion spectroscopy study enables us to estimate energy levels splitting and to locaterare earth ions in these matrices. Several thermal, mechanical and optical characterizations were also performed on the crystals to estimate laser parameters. Finally, first laser tests werecarried out and have shown the potentiality of these materials as amplifier media
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Feng, Min. "Multiple physical properties in the lanthanide complexes involving 2,6-di(pyrazol-1-yl)- pyridine-based tetrathiafulvalene ligands." Thesis, Rennes 1, 2015. http://www.theses.fr/2015REN1S113.
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Dans ce manuscrit, le premier chapitre introduit la cible matériaux multifonctionnels, y compris les connaissances nécessaires sur les différentes propriétés physiques sélectionnées telles que le magnétisme, la luminescence, et la conductivité, ainsi des contributions précédents de nos et d'autres groupes.Dans le chapitre deux, le ligand à base de tétrathiafulvalène avec deux accepteurs dpp (L1 et L2) (TTF = tétrathiafulvalène, dpp = 2,6-di(pyrazol-1-yl)pyridine) et des complexes lanthanide correspondant sont présentés, y compris la synthèse et les caractérisations physiques: structures cristallographique, voltamétrie cyclique, le spectre d'absorption rationalisée par des calculs TD-DFT, des spectres d'émission, et les mesures d’ aimantation AC et DC. Les complexes Eu, Yb, et Er sont emissives.Dans le chapitre trois, un ligand à base de TTF avec deux sites de coordination hétéro L7 et ses deux Dy(III) complexes (C7-1 et C7-2) ont été présentés avec les caractérisations physiques similaires. Les deux complexes Dy révèlent un caractère de molécule aimantIn this manuscript, the Chapter one introduces the target multifunctional materials, including the necessary knowledge of different selected physical properties such as magnetism, luminescence, and conductivity, as well as some of the previous contributions by our and other groups. In Chapter two, the tetrathiafulvalene-based ligand with two dpp acceptors (L1 and L2) (TTF = tetrathiafulvalene, dpp = 2,6-di(pyrazol-1-yl)-pyridine) and the corresponding lanthanide complexes are presented including the synthesis and physical characterizations: single crystal structure, cyclic voltammetry, absorption spectra that rationalized by TD-DFT calculations, emission spectra, and DC and AC magnetic measurements. The complexes Eu, Yb, and Er are emissive. In the Chapter three, a TTF-based ligand with two hetero coordinating sites L7 and its two Dy(III) complexes (C7-1 and C7-2) were presented, which show multi-relaxation SMM behavior
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Todd, 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.
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Montanari, Luca. "Surface Plasmon Induced Luminescence as a Tool for Study of the Ageing of Polymeric Materials." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amslaurea.unibo.it/13361/.
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Lo scopo della presente tesi, svolta presso il Laboratorio LAPLACE di Tolosa, è quello di indagare sulle proprietà ottiche di campioni composti da un substrato di materiale polimerico (bi-axially oriented polyprophilene, BOPP) ricoperto con diversi tipi di elettrodi principalmente tramite misure di elettroluminescenza e di comprendere come queste siano legate al suo deterioramento e invecchiamento
Nella prima parte della tesi, verranno illustrate le misure effettuate su due diverse strutture MIM (metal-insulator-metal), la prima ottenuta utilizzando oro e la seconda utilizzando ITO come elettrodi.
Nella seconda parte, invece, le misure sono state effettuate su campioni multistrato contenenti nano compositi a base di argento, ricoperte con uno strato di ITO che fungerà da elettrodo.
Le misure sulla prima tipologia di campioni hanno evidenziato la presenza di due componenti principali nelle emissioni dovute a elettroluminescenza, una prodotta dal materiale bulk (BOPP) e una scaturita dall’interazione tra il substrato e l’elettrodo metallico, grazie al coinvolgimento dei plasmoni di superficie.
Lo scopo della seconda parte della tesi è quello di comprendere l’effetto che le particelle di argento potrebbero avere sui plasmoni superficiali e sulle emissioni luminose dovute a elettroluminescenza. I risultati ottenuti su questi campioni hanno evidenziato un livello di luce prodotto da elettroluminescenza incredibilmente maggiore rispetto ai campioni aventi ITO e oro come elettrodi.
In conclusione l’impatto delle nano particelle di argento sulle emissioni per elettroluminescenza da BOPP possono essere molteplici e saranno necessari ulteriori studi per comprendere in modo dettagliato tale meccanismo. L’effetto mostrato qui potrebbe risultare molto utile per capire meglio l’elettroluminescenza nei materiali polimerici isolanti da un lato e dall’altro le proprietà foto-fisiche delle nanoparticelle metalliche.
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Machado, Ian Pompermayer. "Luminescência persistente no visível e infravermelho em oxissulfetos de terras raras preparados por síntese no estado sólido assistida por micro-ondas." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/46/46136/tde-17082016-081843/.
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A maioria dos materiais que apresentam o fenômeno da luminescência persistente possuem o íon Eu2+ como ativador, exibindo emissões sintonizáveis entre o azul e o verde. Entretanto, materiais com luminescência persistente na região do vermelho e infravermelho próximo (Near Infrared - NIR) são ainda pouco reportados na literatura. Portanto, foram preparados neste trabalho os materiais TR2O2S.Ln3+ e TR2O2S.Ln3+,Mg2+,Ti3+/IV (TR3+: La, Gd e Y; Ln3+: Eu e Yb) pelo método de síntese no estado sólido assistido por micro-ondas. Os materiais foram caracterizados pelas técnicas de Difração de raios X (DRX), Microscopia eletrônica de varredura (MEV), Espectroscopia de absorção no infravermelho (IV), Espectroscopia de absorção de raios X próximo a borda com radiação síncrotron (XANES), Termoluminescência (TL) e Espectroscopia de excitação na região do UV-UV vácuo com radiação síncrotron. Quando excitados na banda de absorção da matriz (band gap) ou por exemplo, nas bandas de transferência de carga LMCT O2-(2p) → Eu3+(4f6) e S2-(3p) → Eu3+(4f6), os materiais TR2O2S:Eu3+ e TR2O2S:Eu3+,Mg2+,Ti3+/IV apresentam um grande número de bandas de emissão finas atribuídas às transições 5D2,1,0 → 7FJ do íon Eu3+. Os dados espectroscópicos sugerem um alto grau de covalência e uma baixa energia de fônons para as matrizes TR2O2S. Além do mais, os materiais TR2O2S:Yb3+ e TR2O2S:Yb3+,Mg2+,Ti3+/IV apresentam bandas de emissão finas na faixa 900-1050 nm (NIR) atribuídas à transição 2F5/2 → 2F7/2 do íon Yb3+. Os mecanismos de luminescência persistente foram propostos para os materiais TR2O2S:Ln3+ e TR2O2S:Ln3+,Mg2+,Ti3+/IV (TR3+: La, Gd e Y; Ln3+: Eu, Yb) e podem ser via armadilhamento de buracos ou via armadilhamento de elétrons. O mecanismo via armadilhamento de buracos é relativo à excitação dos íons Eu3+ e Yb3+ e explica a existência do fenômeno da luminescência persistente nos materiais sem co-dopantes (TR2O2S:Eu3+ e TR2O2S:Yb3+). De outra forma, o mecanismo via armadilhamento de elétrons ocorre nos materiais TR2O2S:Eu3+,Mg2+,Ti3+/IV e TR2O2S:Yb3+,Mg2+,Ti3+/IV para a emissão oriunda do íon Ti3+. Nos materiais TR2O2S:Eu3+,Mg2+,Ti3+/IV observa-se o processo de transferência de energia Ti3+ → Eu3+, o que leva a uma luminescência persistente mais eficiente do íon Eu3+. Por outro lado, devido à grande diferença de energia entre os íons Ti3+ e Yb3+, o processo de transferência de energia Ti3+ → Yb3+ não acontece para os materiais TR2O2S:Yb3+,Mg2+,Ti3+/IV. Portanto, a luminescência persistente ocorre via mecanismo de armadilhamento de buracos simultaneamente ao de armadilhamento de elétrons, obtendo uma luminescência persistente com contribuição no visível oriunda do íon Ti3+ e no NIR do íon Yb3+. Os materiais apresentam um grande potencial em aplicações e inovação tecnológica na área de fotônica como sondas biológicas luminescentes e sensibilizadores de células solares.Most of persistent luminescent materials have the Eu2+ ion as an activator, displaying tunable emission color from blue to green region. However, there is a few examples of red and near infrared (NIR) persistent luminescent materials reported in literature. In this work, the TR2O2S:Ln3+ and TR2O2S:Ln3+,Mg2+,Ti3+/IV (TR3+: La, Gd and Y; Ln3+: Eu and Yb) luminescent materials were prepared by microwave-assisted solid state synthesis. The materials were characterized with X-ray diffraction, Scanning electron microscopy, Infrared absorption spectroscopy, synchrotron radiation X-ray absorption spectroscopy near edge (XANES), Thermoluminescence (TL) and synchrotron radiation UV-VUV spectroscopy. When excited at the host absorption band (band gap) or at the ligand-to-metal-charge-transfer bands (LMCT), O2-(2p) → Eu3+(4f6) and S2-(3p)→ Eu3+(4f6), the materials TR2O2S:Eu3+ and TR2O2S:Eu3+,Mg2+,Ti3+/IV display a large number of narrow emission bands assigned to Eu3+ 5D2,1,0→7FJ transitions. Spectroscopic data indicate a high degree of covalency and low phonon energy of TR2O2S hosts. The TR2O2S:Yb3+ and TR2O2S:Yb3+,Mg2+,Ti3+/IV materials show emission bands in the range from 900 to 1050 nm (NIR) assigned to the 2F5/2→2F7/2 transitions of Yb3+ ion. The persistent luminescence mechanisms were proposed for TR2O2S:Ln3+ and TR2O2S:Ln3+,Mg2+,Ti3+/IV (TR3+: La, Gd and Y; Ln3+: Eu and Yb) materials, there are two possible ways, hole-trapping or electron-trapping mechanisms. The hole-trapping mechanism is related to the excitation of Eu3+ and Yb3+ ions and explains the persistent luminescence phenomenon in non-co-doped materials (TR2O2S:Eu3+ and TR2O2S:Yb3+). The electron-trapping mechanism governs the persistent luminescence of Ti3+ ion in TR2O2S:Eu3+,Mg2+,Ti3+/IV and TR2O2S:Yb3+,Mg2+,Ti3+/IV materials. The Ti3+ → Eu3+ energy transfer was observed in TR2O2S:Eu3+,Mg3+,Ti3+/IV materials and leads to an improvement of Eu3+ persistent luminescence. On the other hand, due to the large energy levels gap between Ti3+ and Yb3+ ions, there is no Ti3+→Yb3+ energy transfer in TR2O2S:Yb3+,Mg2+,Ti3+/IV materials. Therefore, the persistent luminescence in these materials occurs with hole-trapping and electron-trapping mechanisms simultaneously, obtaining a visible-NIR persistent luminescence composed by Ti3+ and Yb3+ emissions, respectively. The materials exhibit great potential in biological and technological innovation in photonic areas such as luminescent probes and solar cell sensitizers
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Bryant, Mathew James. "Platinum pincer complexes : in pursuit of switchable materials." Thesis, University of Bath, 2016. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.678854.
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The research presented within this thesis is concerned with the design, synthesis, characterisation, and analysis of a series of new compounds of platinum (II), with aims to produce compounds possessing switchable optical properties, and with potential applications as "smart-materials" for use as highly selective sensors.
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Rafiei, Miandashti Ali. "Synthesis, Characterization, and Photothermal Study of Plasmonic Nanostructures using Luminescence Nanomaterials." Ohio University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1553788360252461.
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Sábio, Rafael Miguel. "Nanohybrides luminescents à base de silice et de complexes hétérobimétalliques d-f silyles." Thesis, Toulouse 3, 2016. http://www.theses.fr/2016TOU30399/document.
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Le design de complexes luminescents hétérobimétalliques a suscité un intérêt croissant ces dernières années en raison de leurs propriétés photophysiques uniques. Dans ces complexes de Nd (III) ou Yb (III) associés à des chromophores du bloc d, la forte émission du métal de transition dans le visible est utilisée pour sensibiliser de façon efficace les niveaux f-f du lanthanide(III) qui émet à son tour dans le visible ou l'IR selon la terre rare. Plus spécifiquement l'attention s'est focalisée sur le développement de complexes hétérobimétalliques d-f pour l'émission dans le proche infrarouge (NIR). En effet le proche infrarouge, comparé à l'UV, pénètre plus facilement les tissus biologiques humains notamment la peau. Bien que de telles propriétés confèrent à ces complexes bimétalliques un fort potentiel pour le diagnostic médical, aucun complexe hétérobimétallique d-f greffé de façon covalente à une matrice de silice n'a été décrit. Dans ce travail de nouveaux complexes hétérobimétalliques d-f contenant des ligands silylés ont été préparés et greffés sur la silice. Les complexes monomères [Ru(bpy)2(bpmd)]Cl2 (noté Ru), [Ru(bpy)(bpy-Si)(bpmd)]Cl2 (noté RuL) et [Ln(TTA-Si)3] (noté LnL3) et les complexes hétérobimétalliques d-f Ru-LnL3 et Ln-RuL (Ln = Nd3+, Yb3+) ont été préparés. La caractérisation des complexes a été effectuée par spectroscopie Raman, RMN 1H et 13C RMN. Les spectres RMN 1D 1H et 13C NMR ainsi que 2D de corrélation HSQC confirment les structures proposées. L'étude des propriétés photophysiques met en évidence l'émission de l'élément lanthanide dans le proche infrarouge ainsi que l'efficacité du processus de transfert d'énergie Ru-Ln qui est facilité par le ligand (2,2'-bipyrimidine). Les mesures de durée de vie et de rendement quantique (ΦET) pour le transfert d'énergie indiquent des valeurs remarquables comprises entre 30 et 84 %. La valeur du rendement quantique (ΦET) du complexe d'Yb-RuL, 73,4 %, est à ce jour la plus grande valeur rapportée pour un complexe hétérobimétallique Ru (II)-Yb (III). Le greffage sur différentes matrices de silice, mésoporeuse SiO2 ou dense SiO2 d, a été réalisé. Les nanohybrides SiO2-RuL, SiO2-NdL3 et SiO2-YbL3 ont été obtenus avec des taux de greffage allant de 0,08 à 0,18 mmol de complexe par gramme de silice. [...]The design of heterobimetallic luminescent complexes has gained growing interest in recent years due to their unique photophysical properties. More specifically, the development of heterobimetallic complexes using d-block chromophores to sensitize the near-infrared (NIR) emission of lanthanide complexes (such as Nd(III) and Yb(III)) has received significant attention taking into account their longer emission wavelengths and the interest of the NIR emission which penetrates human tissue more effectively than UV light. These properties give them potential applications in medical diagnostics or biomedical assays. Transitions to excited state levels of transition metal complexes occurring in the visible and characterized by large absorption coefficients, could efficiently sensitize f-f levels of Ln(III) ions. In this work new d-f heterobimetallic complexes containing silylated ligands were prepared supported on silica materials. [Ru(bpy)2(bpmd)]Cl2 (labeled Ru), [Ru(bpy)(bpy-Si)(bpmd)]Cl2 (labeled RuL) and [Ln(TTA-Si)3] (labeled LnL3) and d-f heterobimetallic complexes, Ru-LnL3 and Ln-RuL (Ln = Nd3+, Yb3+) were prepared. Structural characterization was carried out by Raman Scattering, 1H and 13C NMR spectroscopies. Results obtained from 1H-13C HMBC and HSQC correlation NMR spectra confirm the formation of proposed complexes. Photophysical properties studies highlight the efficiency of Ru-Ln energy transfer processes in NIR-emitting lanthanide complexes mediated by conjugated bridging ligand (2,2'-bipyrimidine). Lifetime measurements were carried out and values of quantum yield for energy transfer (?ET) between 30 and 84 % could be evaluated. ?ET of 73.4 % obtained for the Yb-RuL complex is the largest value reported for Ru(II)-Yb(III) heterobimetallic complexes so far. Grafting on different silica matrix was also demonstrated. SiO2-Ru, SiO2-NdL3 and SiO2-YbL3 nanohybrids were obtained with grafting efficiencies from 0.08 to 0.18 mmol g-1 of silica.[...]
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Quintero, Pinzón Carlos Mario. "Luminescent spin crossover nanomaterials : physical properties and applications." Toulouse 3, 2012. http://thesesups.ups-tlse.fr/1899/.
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L'objectif principal de cette thèse est de fournir un nouveau protocole qui permet la détection de la transition de spin (TS) dans un nano-objet unique. Dans ce but, nous proposons d'utiliser la luminescence comme sonde très sensible qui peut être employée à des échelles où d'autres méthodes conventionnelles ne sont plus efficaces. Nous avons cherché à développer des nano-matériaux à TS avec des propriétés de luminescence dans le but d'isoler ces objets et ensuite sonder leurs propriétés via la détection luminescente. Sur la base de techniques de lithographie douce, plusieurs méthodes allant de l'assemblage aléatoire jusqu'à l'assemblage capillaire dirigé de nanoparticules à TS et également la synthèse in situ d'objets isolés luminescents à TS (ca. 150 nm) ont été explorées. Dans le même temps, leur étude en microscopie de fluorescence est présentée et les défis expérimentaux que cette tâche a imposée sont discutés. En outre, l'application potentielle de ces matériaux hybrides en microthermométrie est étudiée. Comme preuve de concept, des films minces de systèmes luminescents à TS ont été déposés sus des micro / nanofils chauffés par effet Joule afin de cartographier leur températureThe main objective of this thesis is to provide a new protocol that permits the detection of the spin crossover (SCO) phenomenon in a single nano-object. To accomplish this, we propose luminescence as a highly sensitive technique that may be employed at scales where other conventional methods are no longer effective. We aimed to develop SCO nano-materials with luminescence properties in order to isolate these objects, address them and then probe their properties via luminescent detection. Methods ranging from random to directed microcappilary assembly of SCO nanoparticles and also in situ synthesis of isolated luminescent SCO objects (ca. 150 nm) based on soft lithographic techniques were explored. At the same time, their investigation in fluorescence microscopy is shown and the experimental challenges that this task imposed are discussed. Also, the potential application of these hybrid materials in microthermometry is studied. As a proof of concept, thin films of luminescent SCO systems were employed to obtain thermal cartographies of gold micro - nanowires heated by Joule effect
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Pinto, Martínez Andrea. "Luminescent gold(I) supramolecular assemblies on materials and biological chemistry." Doctoral thesis, Universitat de Barcelona, 2021. http://hdl.handle.net/10803/672744.
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During the last years, the research group where this Doctoral Thesis has been carried out has been pioneer in the development of different gold(I) complexes and resulting supramolecular assemblages with a wide variety of applications. The starting point of this intensive development of systems is in the study of a gold(I)-alkynyl system with water- soluble phosphines, which gave rise to the formation of a hydrogel. This example was the precedent for an exhaustive study of the aggregation processes of gold(I) complexes, where modifications in the chromophore or the incorporation of charge in the system gave rise to a wide range of morphologies (rods, vesicles, square, stars ...) with different luminescent properties. Taking into account this precedent, this Doctoral Thesis focuses on using the supramolecular chemistry of gold(I) complexes in order to modulate their luminescent properties, taking a further step in the methodology of establishment by the group and designing and investigating new gold(I) compounds and assemblies that present improved properties and are suitable to be studied in different types of applications, ranging from luminescent materials, molecular recognition or biological applications. These complexes have been rationally designed, where the different parts of the molecular structure were selected for a specific application. Phosphines have been chosen as the second coordination site, since they are ligands that can modulate the solubility in different solvents and the nuclearity of the resulting compounds. Carbenes have also been used to introduce planarity into the final compound. A great variety of techniques have been used to demonstrate the correct formation of organic and organometallic compounds (NMR, IR, ESI, and X-ray diffraction). The supramolecular structures obtained have been duly analyzed by DLS, SEM, UV-vis, fluorescence and SAXS.Durante los últimos años, el grupo de investigación donde se ha realizado esta Tesis Doctoral ha sido pionero en el desarrollo de diferentes complejos de oro(I) y ensamblajes supramoleculares resultantes con una amplia variedad de aplicaciones. El punto de partida de este intensivo desarrollo de sistemas se sitúa en el estudio de un sistema de oro(I)- alquinilo con fosfinas solubles en agua, el cual, dio lugar a la formación de un hidrogel. Este ejemplo fue el precedente de un exhaustivo estudio de los procesos de agregación de los complejos de oro(I), dónde modificaciones en el cromóforo o la incorporación de carga en el sistema dio lugar a un amplio abanico de morfologías (bastoncillos, vesículas, cuadrados, estrellas…) con diferentes propiedades luminiscentes. Teniendo en cuenta éste precedente, ésta Tesis Doctoral se centra en utilizar la química supramolecular de los complejos de oro(I) por tal de modular sus propiedades luminiscentes dando un paso más en la metodología de establecimiento por parte del grupo y de diseñar e investigar nuevos compuestos y ensamblajes de oro(I) que presentan propiedades mejoradas y aptos para ser estudiados en diferentes tipos de aplicaciones, yendo de materiales luminiscentes, reconocimiento molecular o aplicaciones biológicas. Estos complejos han sido racionalmente diseñados, dónde las diferentes partes de la estructura molecular fueron seleccionadas para una aplicación determinada. Como segundo sitio de coordinación se han escogido fosfinas, ya que son ligandos que pueden modular la solubilidad en diferentes disolventes y la nuclearidad de los compuestos resultantes. Los carbenos también han sido utilizados por tal de introducir planaridad en el compuesto final. Una gran variedad de técnicas ha sido utilizada para evidenciar la correcta formación de los compuestos orgánicos i organometálicos (RMN, IR, ESI, i difracción de rayos X). Las estructuras supramoleculares obtenidas han sido debidamente analizadas por DLS, SEM, UV-vis, fluorescencia i SAXS.
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Majumder, Manoj. "Theoretical Investigation of Optical and Spectroscopic Properties of Organometallic Complexes and Design of Improved Electroluminescent Materials." Thesis, University of North Bengal, 2018. http://ir.nbu.ac.in/handle/123456789/2768.
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Cornu, Lucile. "Matériaux X-Chromo-luminescents de type spinelle et elpasolite : relation structure-propriétés." Thesis, Bordeaux, 2014. http://www.theses.fr/2014BORD0082/document.
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Les matériaux luminescents sensibles à la température ou l’exposition auxrayons ultra-violets sont de plus en plus recherchés. Dans ces travaux, deux famillesde composés ont été synthétisés et caractérisés.La première famille est celle des composés ZnAl2O4 dopés aux ionsmanganèse de structure spinelle. Ces composés présentent des propriétés dethermo-chromo-luminescence irréversible avec une variation d’émission du rouge auvert en fonction de l’histoire thermique subie par le matériau. Ici les variations delongueurs d’onde d’émission sont dues au changement de l’environnement des ionsluminescents manganèse en fonction de la température. Il a été démontré que lagamme de température de commutation peut être modulée par une variation de lacomposition de la matrice hôte. La seconde famille est celle des elpasolites decomposition Rb2KInF6 dopé au cérium. Ces composés présentent des propriétés dephoto-chromo-luminescence réversible par oxydo-réduction entre les ions cérium etindium. Sous irradiation UV, il est possible de créer des espèces (In+) quiluminescent dans le rouge. Nous avons montré que le retour aux propriétés initialespeut avoir lieu sous irradiation UV à plus hautes longueurs d’onde ou par chauffage.La spécificité du phénomène associé à cette structure et cette compositionparticulière peut s’expliquer par des considérations structurales, la situation spatialedes ions cérium et indium permettant des échanges électroniques par recouvrementorbitalaire de ces deux ionsResearch for luminescent materials sensitive to temperature or UV exposurevariation are increasing. Here we manage to synthesized and characterized materialswhich show such properties.First, spinel structure materials as ZnAl2O4 doped with manganesecompounds exhibit irreversible thermo-chromo-luminescence properties. Thismaterial shows a variation of emission wavelength from red to green with a variationof the thermal history of the sample. These variations are due to a modification of themanganese environment in the structure with the temperature. It was demonstratedthat the temperature range of the luminescence switch can be tuned by themodification of the matrix composition. Secondly, cerium-doped Rb2KInF6compounds with elpasolite structure exhibit reversible photo-chromo-luminescenceproperties. Under UV irradiation, new luminescent species (In+), created by redoxreaction between Ce3+ and In3+ species, and which emits in the red range, can beproduced. We demonstrate the reversibility of the phenomenon by UV irradiation orafter a thermal treatment. The specificity of these properties with this structure andthis composition can be explained by structural consideration: Ce3+ and In3+positioning in the cell allowing electronic exchanges between these ions thanks toorbital overlap
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Hill, Deborah Ann. "X-ray excited optical luminescence (XEOL) and its application to porous silicon." Thesis, University of Warwick, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302693.
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O'Toole, Niall. "Synthèses et caractérisations de complexes luminescents préparés à partir du macrocycle thiacalix[4]arène et l’ion Mn2+." Thesis, Lyon, 2017. http://www.theses.fr/2017LYSE1028/document.
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La thèse est une étude des propriétés photophysiques et photochimiques de systèmes contenant la molécule sulfonylcalix[4]arène, membre de la famille des thiacalixarènes. Une série d'études dans notre laboratoire a révélé qu'un complexe agrégat tétranucléaire de manganèse(II) avec le ligand para-tert-butylsulfonylcalix[4]arène (thiaSO2) montrait une forte émission rouge sous l'action de lumière bleu. Cette découverte surprenante est la base de cette étude doctorale.Le premier chapitre est une revue de la littérature concernant les thiacalixarènes et leurs complexes métalliques. La synthèse et les modifications de ces molécules seront décrites, ansi que leurs propriétés fondamentales.La deuxième partie se concentre sur les propriétés de luminescence. Afin de proposer une explication mécanistique, la réponse de l'émission provenant du complexe (K)[Mn4(thiaSO2)2F] (2) a été étudiée sous des conditions variables de pression, température, pression d'O2 … L'hypothèse que ces systèmes sont capables de produire l'oxygène singulet sera faite.Le troisième chapitre concerne les photoréactions de systèmes en solution des complexes de manganèse(II). La photo-oxydation des ions Mn2+ en Mn3+ a été étudiée et les divers facteurs contribuants à ce processus seront discutés. Le rôle important de l'oxygène et sa transformation en espèces réactives, l'effet du solvant et du pH du milieu de réaction, et l'importance des matériaux de départ, sont confirmés ; nous proposons un mécanisme réactionnel basé sur ces données et la photoréactivité du composé organique calculée par une méthode théorique.La dernière partie montrera la préparation et la caractérisation d'espèces hybrides organique-inorganique par l'insertion d'agrégats [Mn4(thiaSO2)2F]- dans des matériaux LDH (« Hydroxyde Double Lamellaires »). Ces hybrides sont réalisés par des méthodes de chimie douce. Les études préliminaires sur la structure, la luminescence, et la photoréactivité des produits ont été faites. Finalement, un essai a été fait afin de tester la capacité des matériaux hybrides à agir comme photocatalyseur pour l'oxydation de molécules simplesThis thesis is a study of the photophysical and photochemical properties of systems containing the molecule sulfonylcalix[4]arene, a member of the thaicalixarene family. A series of studies in our laboratory revealed that a tetranuclear cluster complex of manganese(II) with the ligand para-tert-butylsulfonylcalix[4]arene (thiaSO2) displayed strong red emission under the action of blue light. This surprising discovery became the basis for this doctoral study.The first chapter is a review of the literature concerning thiacalixarenes and their metal complexes. The syntheses and modifications of these compounds will be described, as well as their fundamental properties.The second part is dedicated to the properties of luminescence. In order to propose a mechanistic explanation, the response of the emission arising from the complex (K)[Mn4(thiaSO2)2F] (2) has been studied under varying conditions of pressure, temperature, O2 partial pressure … The hypothesis that these systems are capable of producing singlet oxygen will be made.The third chapter is concerned with photoreactions of these systems in solution. The photo-oxidation of Mn2+ ions into Mn3+ ions was investigated and the various contributing factors to this process will be discussed. The important role of oxygen and its transformation into reactive species, the effect of the solvent and the pH of the reaction medium, and the importance of the starting material, are all confirmed; we will propose a reaction mechanism based on both these data and the photoreactivity inherent to the organic compound calculated by a theoretical method.The final part will show the preparation and characterisation of organic-inorganic hybrid species by the insertion of [Mn4(thiaSO2)2F]- aggregates into LDH (“Layered Double Hydroxide”) materials. These hybrids were obtained by soft chemistry methods. Preliminary investigations of the structure, the luminescence, and the photoreactivity of these products have been made. Finally, an attempt was carried out to test the capacity of these hybrid materials to act as photocatalysts for the oxidation of simple molecules
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Mohammed, Edris. "Luminescence properties of SrₓCa₁₋ₓS:Cu thin film phosphors for flat panel displays." Diss., Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/30245.
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Leroy, Céline Marie. "Films mésoporeux de TiO2 ou ZrO2 dopés EuIII : de la localisation des ions EuIII à l’étude des corrélations entre les propriétés de luminescence et la réactivité de surface." Thesis, Bordeaux 1, 2009. http://www.theses.fr/2009BOR13906/document.
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La recherche scientifique contemporaine en matière de matériaux est largement orientée autour de l’optimisation et l’élaboration de nouveaux matériaux poly-fontionnels, multi-structurés et aux dimensions réduites. De tels matériaux conduisent à s’intéresser à la problématique des comportements spécifiques résultant des différentes interfaces mises en jeu ; il peut s’agir d’interfaces physiques entre différents milieux (états différents, compositions chimiques différentes …) ou des interfaces entre différentes propriétés. Dans ce contexte, nous nous sommes intéressés aux corrélations pouvant exister entre les propriétés de luminescence et la réactivité de surface de films mésoporeux d’oxyde métalliques dopés avec des ions EuIII. Ces deux propriétés étant fortement dépendantes de la structure des matériaux, une grande partie de notre travail a été dédiée à la caractérisation de cette dernière. Un intérêt particulier a été porté à l’étude des conséquences de la présence des ions EuIII et à la localisation de ces derniers au sein des matrices étudiées. Finalement, il est apparu que la luminescence des ions EuIII au sein des films mésoporeux à base de TiO2 peut permettre de suivre les réactions redox se produisant au sein des pores, comme par exemple la photo-dégradation de composés organiques ou la photo-réduction de sels métalliques. La photo-réduction in situ permet la formation de réseaux périodiques de nanoparticules métalliques. Ces matériaux offrent donc de nombreuses perspectives d’applications dans des domaines aussi variés que les télécommunications optiques, la photonique, la photocatalyse…Materials contemporary scientific research is largely devoted to the optimization and the elaboration of new poly-functional, multi-structured and size-reduced materials. Then, specific behaviors due to the different interfacial aspects of those materials – physical interfaces between different matter states, different chemical phases… or properties interfaces – have become a major issue requiring further investigations. In this context, our work deals with correlations that could be established between luminescence properties and surface reactivity of EuIII-doped metal oxide mesoporous thin films. As properties can be linked to materials structure, an important part of our work has been dedicated to structural characterization. EuIII ions incorporation specific effects and ions location within film walls have been particularly studied. Finally, it appeared that EuIII ions luminescence could provide a mean to follow redox reactions occurring within pores, such as organic compounds photo-degradation or metallic salts photo-reduction. In situ photo-reduction can lead to periodic arrays of metallic nanoparticles. La photo-réduction in situ permet la formation de réseaux périodiques de nanoparticules métalliques. Those materials can open up the way in many applications such as optical telecommunication, photonics, photocatalysis…
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Segura, Daniel Fonseca [UNESP]. "Estudos preliminares da preparação de fibras ópticas plásticas e híbridos orgânicos-inorgânicos luminescentes a partir de poli(metacrilato de metila) comercial." Universidade Estadual Paulista (UNESP), 2010. http://hdl.handle.net/11449/97883.
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Neste trabalho fibras ópticas de PMMA foram preparadas a partir de amostras de PMMA disponíveis comercialmente. As amostras foram termoprensadas a uma temperatura de 230 ºC na forma de bastões homogêneos e livre de bolhas. Desses bastões foi possível obter preformas cilíndricas com diâmetro de aproximadamente 10 mm. Para a obtenção de fibras foi utilizado o método de puxamento de preforma em uma torre de puxamento de características industriais. O puxamento das fibras foi conseguido em temperaturas próximas a 200 ºC possibilitando a confecção de fibras de diâmetro entre 200 µm a 1000 µm, essas fibras possuem uma atenuação entre 23 dB/m e 13 dB/m respectivamente. Esses valores são superiores ao encontrado para uma fibra comercial que é de 4 dB/m. Numa segunda parte do trabalho um novo material híbrido orgânico inorgânico foi preparado, constituído de PMMA e nanopartículas inorgânicas luminescentes de vanadato de ítrio dopado com európio (YVO4:Eu). Para isso foi empregado dois métodos diferentes: a moagem conjunta do PMMA com as nanopartículas com a posterior termoprensagem dessa mistura e a suspensão em solvente, que consistia em solubilizar o PMMA em um solvente contendo uma suspensão das nanopartículas com a sua posterior secagem. Ambos os métodos produziram materiais transparentes e homogêneos. As propriedades espectroscópicas sugerem que a identidade das nanopartículas tenha sido preservada nos compósitos finais. Alguns ensaios de puxamento de fibras a partir dos compósitos foram realizados
In this work PMMA optical fibers were prepared from samples of commercially available PMMA. The samples were processed at 230 ºC to make rods homogeneous and without bubbles. With these rods was possible to obtain cylindrical preforms with a diameter of approximately 10 mm. The drawing of the fibers was achieved at temperatures around 200 ° C enabling the manufacture of fibers with diameters of 200 μm to 1000 μm these fibers have an attenuation between 23 dB/m and 13 dB/m respectively. These values are higher than found for a commercial fiber that is 4 dB/m. In a second part of the work a new organic inorganic hybrid material was prepared, consisting of PMMA and inorganic luminescent nanoparticles of yttrium vanadate doped with europium (YVO4:Eu). For this he was employed two different methods: the joint milling of PMMA nanoparticles with subsequent thermopressing the mixture and suspended in solvent, which was to solubilize the PMMA in a solvent containing a suspension of nanoparticles with subsequent drying. Both methods produced transparent and homogeneous materials. The spectroscopic properties suggest that the identity of nanoparticles has been preserved in the final composite. Some tests of pulling fiber from the composite were performed
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Selivanov, N. I., L. G. Samsonova, T. A. Solodova, and T. N. Kopylova. "Photophysical Properties of Acridine in Solutions and SiO2 Thin Films. Materials for Optical Sensors." Thesis, Sumy State University, 2012. http://essuir.sumdu.edu.ua/handle/123456789/35484.
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Experimental and quantum-chemical investigation of the spectral and luminescent properties of acridine,
and its protonated form was performed. The electronic absorption and fluorescence spectra of the acridine
were studied at room temperature in ethanolic solutions at different pH values and in other solvents
of different chemical nature and polarity.The energies of the excited states, the deactivation rate constants
for the excited states, and the dipole moments are presented, which were obtained by calculations using
the INDO/S method. Sensor properties of acridine immobilized into SiO2 thin films to gaseous ammonia
was studied.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35484
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Pritula, I. M., O. N. Bezkrovnaya, A. G. Plaksyi, Y. L. Slominsky, A. V. Lopin, and A. D. Kachkovskiy. "Composite Materials on the Base of Nanoporous SiO2 Matrices with Polymethine Dyes Molecules." Thesis, Sumy State University, 2013. http://essuir.sumdu.edu.ua/handle/123456789/35594.
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Sol-gel SiO2 matrices with Polymethine dyes (РМ1, РМ2 and РМ3) were synthesized using citric acid
as a catalyst. There were measured the absorption and luminescence spectra of РМ1, РМ2 and РМ3 dyes
(with a concentration of 1·10–5 mole/dm3) in different solvents (ethanol, dimethylformamide, formamide
and water) and in sol-gel SiO2 matrices. The said dyes were found to be present in monomeric form in ethanol,
dimethylformamide and formamide. PM1 dye did not form dimers in water and in matrices and retained
its color. PM2 and PM3 dyes aggregated into the network of SiO2 matrices and in water solution,
and the intensity of their coloration reduced in the course of time.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35594
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Hakat, Yasemin. "Studies on the Preparation, Immobilization, and Luminescence Properties of Zinc Oxide (ZnO)Quantum Dots." Digital Commons @ East Tennessee State University, 2012. https://dc.etsu.edu/etd/1406.
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Quantum dots are a part of very important our technological future because of their intriguing and useful properties. These properties are different in character from those of the corresponding bulk material. Quantum dots are inorganic artificial semiconductor nanocrystal whose electrons influence their physical and chemical properties. Zinc oxide quantum dots were synthesized through an ethanol based precipitation via colloidal synthesis method at various pH values. Various emission colors were obtained because the excited quantum dots of various sizes emitted specific wavelengths of light. The emission spectra indicated that the pH dependent quantum dots were successfully synthesized. Zinc oxide quantum dots were also encapsulated and the luminescence properties examined. The quantum dots that were immobilized in polyisoprene (PI) through chemiluminescence (CL) analyses were found to be stable and were capable of continuing their luminescence properties with extended uses and long- term storage. Linear calibration curves were acquired for concentration of 8.75 x 10-5 M H2O2 in TCPO-CL.
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Zhuang, Yixi. "Red to Near-Infrared Luminescent Materials Activated by Transition Metals for in vivo Imaging and Telecommunication Application." Kyoto University, 2014. http://hdl.handle.net/2433/188799.
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Kyoto University (京都大学)0048
新制・課程博士
博士(人間・環境学)
甲第18361号
人博第674号
新制||人||162(附属図書館)
25||人博||674(吉田南総合図書館)
31219
京都大学大学院人間・環境学研究科相関環境学専攻
(主査)教授 田部 勢津久, 教授 加藤 立久, 教授 杉山 雅人
学位規則第4条第1項該当