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1
Humphrey, Mark Graeme. "Aspects of organometallic chemistry, particularly metal alkynyl and cluster chemistry". Title page, contents and abstract only, 2002. http://web4.library.adelaide.edu.au/theses/09SD/09sdh9267.pdf.
Testo completoAbstract (sommario):
Includes bibliographical references. Details research carried out into the nonlinear optical properties of metal alkynyls, chiefly organoruthenium complexes, showing that these complexes can be designed to have very large NLO coefficients. Also demonstrates the utility of spectroscopic, electrochemical and copmutational aids as predictive tools for NLO materials. Also examines cluster synthesis, reactivity and physical properties using ruthenium clusters and hard-donor ligands, affording a series of cluster complrxes that provide structural models for industrially-important hydrotreating intermediates.
2
Lawrence, Heather Bunting Elizabeth. "Organometallic compounds with non-linear optical properties". Thesis, University of Oxford, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.276835.
Testo completo
3
de, Almeida Katia Júlia. "Optical and Magnetic Properties of Copper(II) Compounds". Doctoral thesis, KTH, Teoretisk kemi, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4743.
Testo completoAbstract (sommario):
This thesis encloses quantum chemical calculations and applications of a response function formalism recently implemented within the framework of density functional theory. The optical and magnetic properties of copper(II) molecular systems are the main goal of this work. In this work, the visible and near-infrared electronic transitions, which have shown a key role in studies on electronic structure and structure-function relationships of copper compounds, were investigated in order to explore the correlation of the positions and intensities of these transitions with the geometrical structures and their molecular distortions. The evaluation of solvent effects on the absorption spectra were successfully achieved, providing accurate and inedit computational insight of these effects for copper(II) complexes. Electron Paramagnetic Resonance (EPR) parameters, that is, the electronic g tensor and the hyperfine coupling constants, are powerful spectroscopic properties for investigating paramagnetic systems and were thoroughly analysed in this work in different molecular systems. Relativistic corrections generated by spin-orbit interactions or by scalar relativistic effects were taken into account in all calculations. In addition, we have designed a methodology for accurate evaluation of the electronic g tensors and hyperfine coupling tensors as well as for evaluation of solvent effects on these properties. It is found that this methodology is able to provide reliable and accurate results for EPR parameters of copper(II) molecular systems. The spin polarization effects on EPR parameters of square planar copper(II) complexes were also considered, showing that these effects give rise to significant contributions to the hyperfine coupling tensor, whereas the electronic g tensor of these complexes are only marginally affected by these effects. The evaluation of the leading-order relativistic corrections to the electronic g tensors of molecules with a doublet ground state has been also taken into account in this work. As a first application of the theory, the electronic g tensors of dihalogen anion radicals X$_2^-$ (X=F,~Cl,~Br,~I) have been investigated and the obtained results indicate that the spin--orbit interaction is responsible for the parallel component of the g tensor shift, while both the leading-order scalar relativistic and spin--orbit corrections are of minor importance for the perpendicular component of the g tensor in these molecules since they effectively cancel each other. Overall, both optical and magnetic results show quantitative agreements with experiments, indicating that the methodologies employed form a practical way in study of copper(II) molecular systems including those of biological importance.QC 20100714
4
de, Almeida Katia Júlia. "Optical and magnetic properties of copper(II) compounds /". Stockholm : Department of Theoretical Chemistry, School of Biotechnology, Royal Institute of Technology, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4743.
Testo completo
5
Rachford, Aaron A. "Designing and investigating molecular bistability in ruthenium dimethylsulfoxide complexes /". View abstract, 2007. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:3286186.
Testo completo
6
Hissink, Catharina Everdina. "Silicon-Bridged donor-acceptor compounds: synthesis and nonlinear optical properties". [S.l. : [Groningen] : s.n.] ; [University Library Groningen] [Host], 1996. http://irs.ub.rug.nl/ppn/148933343.
Testo completo
7
Wijngaard, Jan Hendrik. "Magnetic and magneto-optical properties of some transition metal compounds". [S.l. : [Groningen : s.n.] ; University Library Groningen] [Host], 1990. http://irs.ub.rug.nl/ppn/297971859.
Testo completo
8
Gunes, Mustafa. "Optical and electronic properties of nitrogen containing III-V compounds". Thesis, University of Essex, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.528840.
Testo completoAbstract (sommario):
The main aim of this project is to carry out a critical and in depth study of electrical, optical and magneto transport properties of nitrogen containing III-V compounds such as bulk InN, In-rich Inl-xGaxK, GaN/lnN/Ga)J and n- and p- modulation doped Galni'1As QWs. Various experimental results presented and discussed provide fundamental important physical and electronic understanding which does not exist in the current literature such as a Superconductivity Phase transition in Mg-doped and unintentionally doped InN and also magnetotransport properties of modulation doped dilute nitrides. The plausible mechanisms are discussed in detail to explain the existence of the superconductivity in Mg and undoped InN samples. The optical properties of MBE grown III-nitrides and III-V-nitrides samples were investigated using steady state photoluminescence, Raman spectroscopy and spectral photoconductivity techniques while electrical properties were determined with Hall and magnetotransport measurements at low temperature T=1.6 K. The composition dependence of Longitudinal Optical (LO) phonon energies in undoped and Mg doped Inl_xGaxN samples are determined using two independent techniques in the range of Ga fraction from x=O to x=56%. The techniques used are the Raman and the temperature dependent momentum relaxation measurements at high temperatures where LO phonon scattering dominates the transport. The first study of spectral photoconductivity in Mg-doped indium rich GaxIn1_xK is presented. Spectral photoconductivity have three broad peaks at hw =0.65, 1.0 and l.4 eV. It is claimed that Indium segregation in the material might have occurred giving rise to three broad peaks in the photoconductivity spectra. The temperature dependence of the photoconductivity peaks suggest strongly that minority carrier trapping occurs in the material and the trapping energy of Erh=103±15meV is comparable to the Mg activation energy for InN .
9
Tong, Ka Lap. "Electrical and optical properties of triphenylamine-based compounds and devices". HKBU Institutional Repository, 2006. http://repository.hkbu.edu.hk/etd_ra/718.
Testo completo
10
Exley, James Richard. "Electrical and optical properties of novel phthalocyanine compounds for sensor devices". Thesis, Sheffield Hallam University, 1995. http://shura.shu.ac.uk/7110/.
Testo completoAbstract (sommario):
UV/visible spectrophotometry measurements, together with measurement of the temperature dependence of ac parameters G (conductance), C (capacitance) and tan (dielectric loss) for 20Hz
11
Zhu, Bairen, e 朱柏仁. "Optical study on two dimensional transition metal dichalcogenides". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/208045.
Testo completoAbstract (sommario):
Atomically thin group-VI transition metal dichalcogenides (TMDC) has been emerging as a family of intrinsic 2-dimensional (2D) crystals with a sizeable bandgap in the visible and near infrared range, satisfying numerous requirements for ultimate electronics and optoelectronics. This intrinsic 2D crystal also provides a perfect platform for physics study in 2D semiconductors. The characteristic inversion symmetry breaking presented in monolayer TMDCs leads to non-zero but contrasting Berry curvatures and orbital magnetic moments at K/K’ valleys located at the corners of the first Brillouin zone. These features provide an opportunity to manipulate electrons’ additional internal degrees of freedom, namely the valley degree of freedom, making monolayer TMDC a promising candidate for the conceptual valleytronics. Besides, the strong spin-orbit interactions and the subsequent spin-valley coupling demonstrated in 2D TMDCs open potential new routes towards quantum manipulation.
In this thesis, I give a brief review on the background and our progress of the physics study in 2D TMDCs (MoS2, WS2) via optical spectroscopy. Particularly, our experimental approach on the excitonic effect, valley dependent circular dichroism, and the spin-valley coupling in monolayer and bilayer TMDCs are elaborated in individual chapters.published_or_final_version
Physics
Doctoral
Doctor of Philosophy
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俞佩賢 e Pui-yin Yu. "Metal alkylidyne complexes as building blocks for molecular materials". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1998. http://hub.hku.hk/bib/B31238002.
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Sereika, Raimundas. "Investigation of Electronic Structure, Optical and Dynamical Properties of AVBVICVII type Compounds". Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2013. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2012~D_20130114_082030-02721.
Testo completoAbstract (sommario):
In the dissertation AVBVICVII type compounds are analyzed theoretically and experimentally. Theoretical studies were carried out using Density Functional Theory (DFT), along with the Full Potential Linearized Augmented Plane Wave (FP-LAPW) method and the Generalized Gradient Approximation (GGA). For calculations Wien2k and PHONON comp. packages were used. Experimental studies were performed using spectroscopic ellipsometry method and measuring permittivity (electrical capacitance) as a function of temperature. The study discusses AVBVICVII type compounds’ inter-atomic chemical bonding, the electronic structure, optical properties, lattice dynamics, vibrational thermodynamic functions and dielectric properties in the paraelectric, ferroelectric and antiferroelectric phases.Disertacijoje teoriškai ir eksperimentiškai nagrinėjami AVBVICVII tipo junginiai. Teoriniai tyrimai atlikti naudojantis tankio funkcionalo teorija kartu su pilno potencialo tiesinių padidintų plokščių bangų metodu ir apibendrinto gradiento aproksimacija. Skaičiavimams naudoti Wien2k ir PHONON komp. paketai. Eksperimentiniai tyrimai buvo atliekami naudojantis spektroskopinės elipsometrijos metodais bei matuojant dielektrinės skvarbos (elektrinės talpos) priklausomybes nuo temperatūros. Darbe nagrinėjamas AVBVICVII tipo junginių tarpatominis cheminis ryšys, elektroninė struktūra, optinės savybės, gardelės dinamika, virpesių termodinaminės funkcijos ir dielektriniai pokyčiai paraelektrinėje, feroelektrinėje ir antiferoelektrinėje fazėse.
14
Olchowka, Jacob. "Structural versus optical properties in selected Bismuth based oxo-salts and compounds". Thesis, Lille 1, 2015. http://www.theses.fr/2015LIL10088/document.
Testo completoAbstract (sommario):
Le développement de nouveaux matériaux luminescent pour les LEDs du futur, qui ont pour objectifs de préserver l’environnement et de réduire les dépenses énergétiques, est un thème de recherche d’actualité et un défi extrêmement intéressant pour de nombreux chercheurs. Actuellement, la plupart des LEDs commerciales sont des matériaux dopés aux lanthanides. Cependant, la situation économique et politique actuel est telle que pour l’approvisionnement en lanthanides, les pays européens sont dépendant des pays asiatiques qui ont le monopole sur la production et l’exportation des ceux-ci. Dans ce contexte, mes travaux de thèses effectués en collaboration avec l’UCCS de Lille (France) et l’Université de Siegen en Allemagne ont pour objectifs d’étudier les propriétés photoluminescentes de nouveaux oxydes ou oxohalogénures de Bismuth (sans lanthanides) étudiés préalablement par l’UCCS pour leurs caractéristiques structurales. Dans les phases sélectionnées, la connectivité des tétraèdres oxo-centrés O(BiM)4 est un paramètre clé permettant de jouer sur les propriétés optiques en changeant de polytype ou de composition chimique. De ce fait, un des objectifs de cette thèse est de déterminer les paramètres importants permettant de façonner les propriétés optiques de Bi3+ sur des bases de simples concepts tels que la connectivité du Bi, la stéréo-activité de sa paire d’électrons libres ou les structures électroniques…etc. L’étude des familles BiM2XO6 (M=Mg, Cd, Zn et X= P, As, V) et ABiO2X (A=Ca, Cd, Sr, Ba et X=Cl, Br) qui possèdent une émission intense à température ambiante valident la pertinence de ces travauxThe development of luminescent materials for future LEDs is currently a hot-topic with respect to energy saving materials and it is an interesting challenge for many researchers to find the luminescent materials of tomorrow. Most of the current commercial LEDs are based on lanthanide activators. The economic and political context leads the European countries to be dependent on the Asian monopole, in terms of the production and exportation of lanthanides. In this context, my PhD work developed in collaboration with the UCCS at Lille, France and the University of Siegen, Germany, deals with the photoluminescence properties of some novel Bi3+ oxo-salts phosphors (lanthanide free) studied so far by the french partner for their structural aspects. In the selected phases, one key-parameter is the degree of connectivity between oxo-centered O(Bi,M)4 tetrahedra, which allows a fine tuning of optical properties from one polytype to another one and tuning the chemical composition. Therefore, one goal of this work concerns the deduction of the important parameters tailoring the Bi3+ optical properties, on the basis of simple concepts, e.g. Bi bonding scheme, Bi3+ lone pair (LP) stereo-activity, electronic structures … etc. The investigation of the BiM2XO6 (M/M´=Mg, Cd, Zn and X=P, As, V) and ABiO2X (A=Ca, Cd, Sr, Ba and X=Cl, Br) families validated the pertinence of this study, leading to bright luminescence at room temperature
15
Malicki, Michal. "Electronic and optical properties of hybrid gold - organic dye systems". Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/31742.
Testo completoAbstract (sommario):
Thesis (Ph.D)--Chemistry and Biochemistry, Georgia Institute of Technology, 2010.Committee Chair: Marder, Seth; Committee Co-Chair: Perry, Joseph; Committee Member: Dickson, Robert; Committee Member: El-Sayed, Mostafa; Committee Member: Riedo, Elisa. Part of the SMARTech Electronic Thesis and Dissertation Collection.
16
Golea, Mostefa. "AB(2)C(4) semiconducting compounds crystal growth, intrinsic defects and optical properties". Thesis, University of Ottawa (Canada), 1988. http://hdl.handle.net/10393/5374.
Testo completo
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Yang, Lin. "Interaction of molecules and helical nanoparticles characterized by electronic circular dichroism". HKBU Institutional Repository, 2018. https://repository.hkbu.edu.hk/etd_oa/523.
Testo completoAbstract (sommario):
It is of fundamental significance to differentiate an enantiomer from its mirror image (i.e., enantiodifferentiation), through monitoring optical activity (OA) of enantiomers that is typically characterized by electronic circular dichroism (ECD or CD) in the UV-visible region. However, sub-wavelength molecular dimensions substantially prevent enantiomers from effectively perceiving the different circular polarization states, leading to low enantiomeric OA and weak enantiodifferentiation. Some approaches have been developed to amplify the enantiomeric OA; alternatively, on the basis of the emerging chiral metamaterials of metallic helical nanoparticles (HNPs) I devise two methods to enhance the enantiodifferentiation. First, I employ glancing angle deposition (GLAD) to deposit Ag HNPs with a helical pitch (P) larger than wire diameter (d) of the helical, i.e., Ag nanohelices (AgNHs). AgNHs exhibit strong plasmonic CD composed of a broadband longitudinal mode (i.e., L-mode) in the visible region, a transverse mode (i.e., T-mode) at a wavelength of ~370 nm, and a dielectric mode in the deep UV region (at a wavelength shorter than 320 nm). Adsorption of alkyl ligands on the AgNHs markedly weakens the two plasmonic CD modes, and the T-mode is weakened more seriously than the L-mode. The deterioration of the plasmonic CD is exacerbated with increasing the bonding energy of the Ag-alkyl ligand contacts, attributed to the increase of the dielectric constant of the medium of the AgNHs (εr) and the electron withdrawal from the AgNHs towards the alkyl ligands. Derived from the ligand-induced weakening of the plasmonic CD, enantiodifferentiation of L-Glutathione (L-GSH) from D-GSH is dramatically enhanced. The chiroptical weakening sensitively varies with the absolute configuration of GSH, resulting in an enantiodifferentiation anisotropic g factor of ~0.5 that is independent on the AgNH helicity. The AgNH-induced anisotropy g factor is superior to those obtained by other methods, by 2 - 4 orders of magnitude. It is the largest achieved up-to-date, as high as one-fourth of the theoretical maximum. Second, I operate GLAD with fast substrate rotation to reduce P less than d, to generate AgHNPs that exhibit negligible dielectric CD in the deep UV region, offering a helical substrate to directly amplify the OA of enantiomers grafted on the AgHNPs. The anchoring of enantiomers on AgHNPs with the sub-5 nm P leads to the enantioselective amplification of the enantiomeric OA in roughly ten folds; the LH- and RH-AgHNPs give rise to amplify the OA of (S)- and (R)-enantiomers, respectively. It is ascribed to the change of the dihedral angle of an enantiomer adsorbed on AgHNPs. Such the enantioselective amplification tends not to occur as long as P > 5 nm. Moreover, given the enantiodifferentiation of biomolecules that are typically dissolved in an aqueous solution, the effect of water on the plasmonic CD of AgHNPs is investigated and compared with that of AgNHs. Hydrophobic AgNHs with high structural porosity give rise to the irreversible water effect on the plasmonic CD; and hydrophilic AgHNPs with low structural porosity lead to the reversible water effect. At the end, I devise a new methodology to generate plasmonic CD through chirality transfer from chiral host to achiral guest, owing to the helicity duplication of the achiral guest from the chiral host. It leads to inducing chiroptical activity of the achiral guest made of some plasmonic materials that aren't facilely sculptured in the helical. The new methodology effectively broadens the range of materials made from the chiral nanostructures, which is on demand to develop diverse chirality-related bioapplications.
18
Stuppi, Mary Margaret Maliniak 1965. "Synthesis, growth and optical characterization of doped lanthanum magnesium aluminate". Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/277099.
Testo completoAbstract (sommario):
Solid-state lasers are of great interest and importance in infrared sensing and imaging devices as well as in other applications. The objective of this research was to study the synthesis, crystal growth, and optical characterization of a material recently discovered for its potentially useful optical properties: lanthanum magnesium aluminate (LMA). In these experiments, samples of LMA were grown by the vertical gradient freeze (VGF) technique. This technique has most recently been used to grow high quality titanium doped sapphire crystals mainly due to the inherent stability of this system in providing a stationary heat zone during growth runs. The furnace used for this growth technique also has the advantage of requiring a reducing atmosphere which may be used, if desired, to maintain reduced valence states of the dopant ions. This thesis discusses tunable lasers, crystal growth techniques, and the results of the study on LMA.
19
Henwood, Adam Francis. "Tuning the physical and optoelectronic properties of phosphorescent iridium(III) complexes : applications to organic semiconductor devices". Thesis, University of St Andrews, 2017. http://hdl.handle.net/10023/12976.
Testo completoAbstract (sommario):
This thesis explores the design, synthesis and characterisation of iridium(III) complexes for optoelectronic applications; in particular, cationic [Ir(CˆN)₂(NˆN)]⁺-type emitters (where CˆN is an anionic bidentate cyclometalating ligand such as 2-phenylpyridinato, ppy, and NˆN is a neutral bidentate ligand such as 2,2'-bipyridine, bpy) for use in light-emitting electrochemical cells (LEECs). Design strategies aim to achieve high photoluminescence quantum yields (Φ[sub](PL)) for these complexes. Chapter 1 provides an overview of the fundamental photophysics of luminescent transition metal complexes, before reviewing state of the art iridium complexes employed in LEEC devices. Chapter 2 employs a combination of the electron-deficient 2,4-difluorophenylpyridine (dFppy) CˆN ligand and various functionalised biimidazole (biim) NˆN ligands. Within the family of different biim ligands the emission energy does not vary significantly, but the excited state kinetics di.er depending on the rigidity of the biim ligand. Combining the lead biim ligand with a sterically bulkier CˆN ligand gives an iridium complex that emits deep blue light with 90% Φ[sub](PL) in MeCN. Chapter 3 describes an approach to replacing the electrochemically unstable aryl carbon-fluorine bonds in dFppy, while maintaining the deep blue emission colour observed for the complexes in Chapter 2. Chapter 4 expands on the concept of rigid biim ligands to bibenzimidazoles (bibenz). Combining conjugated bibenz NˆN ligands with more conjugated CˆN ligands allows for the emission colour of these complexes to be tuned to the orange/red. The Φ[sub](PL) necessarily falls due to the energy gap law, but is nevertheless higher than values measured for reference complexes. Chapter 5 explores the use of an arylazoimidazole ligand with donor-acceptor intraligand charge transfer characteristics in order to red-shift the emission further. The resultant complex is poorly emissive, but shows a panchromic absorption profile and high molar absorptivity, which is unusual for iridium(III) complexes. The absorption profile can be tuned as a function of the protonation state of the imidazole.
20
Bair, Joseph Spencer. "Synthesis and optical properties of four oligothiophene-ruthenium complexes and synthesis of a bidentate ligand for C-F bond activation /". Diss., CLICK HERE for online access, 2006. http://contentdm.lib.byu.edu/ETD/image/etd1636.pdf.
Testo completo
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Sullivan, Philip A. "Theory guided design and molecular engineering of organic materials for enhanced second-order nonlinear optical properties /". Thesis, Connect to this title online; UW restricted, 2006. http://hdl.handle.net/1773/11569.
Testo completo
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Vaughan, Thomas Alexander. "Magneto-optics of InAs/GaSb heterostructures". Thesis, University of Oxford, 1995. http://ora.ox.ac.uk/objects/uuid:52b3d4c8-04f2-4ee8-b5a5-382934807722.
Testo completoAbstract (sommario):
The optical properties of InAs/GaSb heterostructures under applied magnetic fields are studied in experimental and theoretical detail. The InAs/GaSb system is a type-II "crossed-gap" system, where the valence band edge of GaSb lies higher in energy than the conduction band edge of InAs. This leads to a region of energy above the InAs conduction band where conduction and hole states mix. Thin-layer superlattices remain semiconducting due to confinement effects, but thick-layer superlattices experience charge transfer which leads to intrinsic carrier densities approaching 1012 cm-2 per layer. Existing multi-band modeling techniques based on the k·p formalism are discussed, and a method of solving superlattice band structure (the "momentum-matrix" technique) is presented. The quantizing effects of the superlattice layers and applied magnetic fields are investigated, and the selection rules for optical transitions are derived. Standard cyclotron resonance (CR) is used to study effective masses in InAs/GaSb structures. The heavy hole mass is found to be strongly orientation-dependent, with a mass in the [111] orientation reduced 25% from the [001] mass. The electron mass is found to be roughly isotropic with respect to growth orientation, but shows variation with the InAs width due to quantum confinement effects. CR of InAs/GaSb heterojunctions display hitherto unexplained oscillations in linewidth, intensity, and effective mass. A model is proposed which explains the oscillations, based on the intrinsic nature of the InAs/GaSb system. CR is performed on an InAs/GaSb heterojunction using a free-electron laser, where due to the high intensities (on the order of MW/cm2) the absorption process saturates. This saturation allows for a determination of non-radiative relaxation lifetimes, and through the energy dependence of these lifetimes the magnetophonon effect is observed, allowing a direct measurement of LO-phonon-assisted energy relaxation rates. Coupling is introduced into the standard CR experiment, either by tilting the sample with respect to the magnetic field, or by applying a metal grating to the surface. These coupled CR experiments have striking qualitative results which allow for determination of subband separation energies and coupling matrix elements. Photoconductivity experiments are performed on thin-layer (semiconducting) superlattices, showing optical response at far-infrared wavelengths (5-20 μm). The results are compared with k·p calculations. One sample is processed for vertical transport, in which conduction occurs perpendicular to the superlattice layers. Strong optical response from this sample indicates the viability of InAs/GaSb-based far-infrared detectors. The momentum-matrix technique is used to predict optimum parameters for semiconducting superlattices with band gaps in the far-infrared. Semimetallic structures are studied via a multi-band self-consistent model, with results corroborating with and extending previous work. Intrinsic structures under applied magnetic field are modeled theoretically for the first time.
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Rush, Georgina E. "Preparation and characterization of novel inorganic optical materials". Thesis, University of Kent, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.365214.
Testo completo
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Wang, Rongxin. "Preparation and post-annealing effects on the optical properties of indium tin oxide thin films". Click to view the E-thesis via HKUTO, 2005. http://sunzi.lib.hku.hk/hkuto/record/B31546171.
Testo completo
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Hierlinger, Claus. "Synthesis, characterisation and optoelectronic properties of phosphorescent iridium complexes : from five to six-membered ring chelates". Thesis, University of St Andrews, 2018. http://hdl.handle.net/10023/16126.
Testo completoAbstract (sommario):
Here, the design, synthesis and characterisation and the optoelectronic properties of Ir(III) complexes for application in nonlinear optical and electroluminescent devices are described. The type of complexes varies from those of the form [Ir(C^N)2(N^N)]+ with conjugated and nonconjugated ligands (where C^N = cyclometalating ligand and N^N = neutral ligand) to those of the form [Ir(C^N^C)(N^N)Cl] (where C^N^C = tridentate tripod ligand). Chapter 1 gives an introduction into photophysics occurring in transition metal complexes and possible applications in visual displays. The background of nonlinear optical (NLO) properties and the use of transition metal complexes as NLO chromophores is described. In Chapter 2, the impact of the use of sterically congested cyclometalating ligands on the photoluminescence properties of cationic iridium(III) complexes and their performance in light-emitting electrochemical cells is investigated. Chapter 3 explores the use of electron donors on the cyclometalating ligand towards modulating the NLO properties of the complexes. Combining strongly electron-donating substituents on the C^N ligand and electron-accepting substituents on the N^N ligand results in strong NLO activity. Chapter 4 summarises a new series of cationic iridium(III) complexes bearing benzylpyridinato as cyclometalating ligands. The methylene spacer in the C^N ligands provides flexibility, resulting in two conformers. NMR studies combined with density functional theory (DFT) studies show how the fluxional behaviour is influenced by the choice of the ancillary ligand. In Chapter 5, Ir(III) complexes bearing an unusual nonconjugated bis(six-membered) tridentate tripod ligand of the form [Ir(C^N^C)(N^N)Cl] are introduced. Depending on the substitutions of the C^N^C ligand phosphorescence ranging from yellow to red was obtained. Substitution of the N^N results in a panchromatic NIR dye, suitable for DSSC applications. In Chapter 6, the concept of a nonconjugated ligand was expanded to the N^N ligand. Blue-green and sky-blue emission was obtained, demonstrating a strategy to successfully tune the emission to the blue.
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Rabia, Kaneez [Verfasser], e Christine A. [Akademischer Betreuer] Kuntscher. "Structural and optical properties of transition-metal compounds under pressure / Kaneez Rabia. Betreuer: Christine A. Kuntscher". Augsburg : Universität Augsburg, 2013. http://d-nb.info/1077701799/34.
Testo completo
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Berdibek, Shapagat. "Measurement of optical properties of molten salts and metallic compounds for advanced solar and nuclear systems". Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/106769.
Testo completoAbstract (sommario):
Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2015."June 2015." Cataloged from PDF version of thesis.
Includes bibliographical references (page 29).
Renewable energies can reduce the dependence on fossil fuels. Solar thermal systems designed to use molten salts to directly absorb the solar heat are promising due to (1) potentially higher efficiency in capture of sunlight and (2) use of the salt to simultaneously capture sunlight and store heat in the salt. The optical properties of the molten salts are crucial for the design of such thermal systems because they determine the depth of the salt required to absorb sunlight and allow modeling of the performance of such systems. Molten salts are also being developed as coolants for high temperature reactors. Optical properties are also required to determine the radiative heat transfer of the coolant. The objectives of this thesis were to build a better system to measure these properties and measure the optical properties of the proposed salt for a direct absorption concentrated solar thermal system. The attenuation coefficient of light in a binary nitrate salt mixture (KNO 3-NaNO3 40-60 wt%) was measured over the wavelength range 833-2500 nm and the temperature range 300-400°C. This salt is the leading candidate for the first generation of a proposed concentrated solar power on demand (CSPonD) concept [3]. The relevant data was obtained using a FTIR spectrometer and an experimental apparatus designed for semitransparent liquids. The apparatus was validated using the published data for the attenuation of light in deionized water. The attenuation coefficients of the binary nitrate salt mixture for the lower wavelengths matched the data obtained by Passerini [1]. For the longer wavelengths, the attenuation coefficient peaked around 2.5 Pm as predicted by Drotning [2]. Since certain metallic components of solar and nuclear systems are exposed to the molten salt, it is important to characterize the behavior of their reflectivity in the presence of the molten salt. The reflectivity of 304L stainless steel was measured for the wavelength range 600-5000 nm at incident angles of light 10°, 40°, and 70° after an 8-day molten salt immersion test. The reflectivity was measured to be less than 10% for the solar spectrum.
by Shapagat Berdibek.
S.B.
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Chung, In. "Exploratory synthesis in molten salts characterization, nonlinear optical and phase-change properties of new chalcophosphate compounds /". Diss., Connect to online resource - MSU authorized users, 2008.
Cerca il testo completo
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Wang, Rongxin, e 王榮新. "Preparation and post-annealing effects on the optical properties of indium tin oxide thin films". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2005. http://hub.hku.hk/bib/B31546171.
Testo completo
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Ünal, Bayram. "Optical, electrical and structural properties of nanostructured silicon and silicon-germanium alloys". Thesis, De Montfort University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.391480.
Testo completo
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Shah, Syed Hassan. "Study of nonlinear optical properties of indium arsenide/gallium arsenide and indium gallium arsenide/gallium arsenide self-assembled quantum dots". Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 97 p, 2008. http://proquest.umi.com/pqdweb?did=1460350251&sid=5&Fmt=2&clientId=8331&RQT=309&VName=PQD.
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郭子中 e Chi-chung Kwok. "Functional light-emitting materials of platinum, zinc and boron for organic optoelectronic devices". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2005. http://hub.hku.hk/bib/B34617693.
Testo completo
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Schucan, Gian-Mattia. "Generation of squeezed light in semiconductors". Thesis, University of Oxford, 1999. http://ora.ox.ac.uk/objects/uuid:417b1d31-8d25-42db-b707-32bd460b4183.
Testo completoAbstract (sommario):
We present experimental studies based on all three methods by which the generation of squeezed light in semiconductors has thus far been demonstrated experimentally: Fourwave mixing, multi-photon absorption and direct generation at the source. Four-wave mixing was used to generate femtosecond-pulsed quadrature squeezed light by cross-phase modulation in single-crystal hexagonal CdSe at wavelengths between 1.42 and 1.55 μm. We measured 0.4 dB squeezing (1.1 dB is inferred at the crystal) using 100 fs pulses. The wavelength and the intensity dependence, as well as variations in the local oscillator configuration were investigated. At higher intensities squeezing was shown to deteriorate owing to competing nonlinear processes. We also characterised the nonlinear optical properties of CdSe in this wavelengths range using an interferometric autocorrelator. In addition, we studied the feasibility of extending this technique to AlGaAs waveguides. The key problems are addressed and solutions are proposed. In a different experiment we used an AlGaAs waveguide to demonstrate for the first time photon-number squeezing by multi-photon absorption. By tuning the pump energy through the half bandgap energy we could effectively select two- or three-photon absorption as the dominant mechanism. Squeezing by these two mechanisms could be clearly distinguished and was found to be in good agreement with longstanding theoretical predictions. We also established the generality of the effect, by demonstrating the same mechanism in organic semiconductors, where it led to the first ever observation of squeezed light in an organic material. Finally, we present our measurements of photon-number squeezing in high-efficiency double heterojunction AlGaAs light-emitting diodes. We measured squeezing of up to 2.0 dB. In addition, we observed quantum noise correlations when several of these devices were connected in series.
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Chen, Xuejun Luna. "Crystallographic, magnetic and optical properties of I2. Mn.IV.VI4. compounds with I = Cu, log., IV-Si, GE, Sn and VI =S, Se, Te". Thesis, University of Ottawa (Canada), 1993. http://hdl.handle.net/10393/6626.
Testo completoAbstract (sommario):
A systematic study was performed on the structural, magnetic and optical properties of polycrystalline I$\sb2$.Mn.IV.VI$\sb4$ compounds with I = Ag or Cu, IV = Si, Ge, Sn, VI = S, Se and Te. In X-ray diffractometry, three different crystal structures were observed, two corresponding to the tetragonal stannite and orthorhombic wurtz-stannite structures reported previously, and thirdly a cubic rock salt-like structure. Magnetic susceptibility ($\chi$) measurements showed that most of the selenide phases were ferrimagnetic. Optical absorption measurements were made to determine values of optical energy gap E$\sb{\rm o}$ for a number of the single phase samples. When the values of these various parameters ($\rm a\sb{e}, T\sb{N}, \theta\sb{a}$ and E$\sb{\rm o}$) were compared for the various phases, it was found that the phases could be classified into five different sets. In each case investigated, the variation of E$\sb{\rm o}$ with temperature was found to agree well with the theoretical predictions of Alexander et al. (76A1). (Abstract shortened by UMI.)
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MALAVAZI, JEFFERSON. "Caracterização microestrutural dos compostos intermetálicos e seu efeito no comportamento mecânico nas ligas de Al-9%Si com adições de Fe e Mn". reponame:Repositório Institucional do IPEN, 2013. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10554.
Testo completoAbstract (sommario):
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Dissertação (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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TOFFOLI, DANIEL J. "Caracterizacao espectroscopica de complexos hipocrelina B: lantanideos para uso em terapia fotodinamica". reponame:Repositório Institucional do IPEN, 2008. http://repositorio.ipen.br:8080/xmlui/handle/123456789/9374.
Testo completoAbstract (sommario):
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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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Grelaud, Guillaume. "New electrochromic organometallic materials for light modulation". Phd thesis, Rennes 1, 2012. http://www.theses.fr/2012REN1S120.
Testo completoAbstract (sommario):
Au cours de cette thèse, de nouveaux complexes alcynyles du fer et du ruthénium ont été synthétisés et caractérisés. Ces composés ont été élaborés pour permettre l'électro-commutation de leurs propriétés en optique non linéaire (ONL) entre plusieurs états redox. Dans un premier temps, des unités hétéro-bimétalliques ferrocène-ruthénium ont été étudiées. Il a pu être démontré que ces unités, qui sont des complexes à valence mixte de classe II dans leur état mono-cationique, possèdent les propriétés électrochromiques requises pour leur incorporation dans des assemblages conjugués plus étendus et actifs en ONL. Dans un second temps, des complexes octupolaires possédant un espaceur central de type triphénylamine ou oxyde de triphénylphosphine ont été préparés. Dans le cas des premiers, un complexe octupolaire hexanucléaire à six états redox distincts a été obtenu tandis qu'avec les seconds, un espaceur plus ‟étendu” a été requis pour optimiser les propriétés optiques de ces assemblages. Un électrochromisme marqué a pu être observé en solution pour tous ces complexes. Finalement, d'autres assemblages organométalliques ont également été étudiés. Ainsi, la fonctionnalisation d'un groupement ferrocényl-alcynyl de ruthénium avec un alcyne vrai a permis de greffer cet ensemble dinucléaire original sur une surface de silicium, ouvrant la voie à l'obtention d'interfaces électro-commutables. Par ailleurs, le potentiel des complexes ferrocényl-allénylidènes du ruthénium pour moduler les propriétés optiques de ce chromophore à la fois par oxydation et par réduction a été mis en évidenceDuring this PhD, new iron and ruthenium alkynyl complexes have been synthesized and characterized. These complexes had been prepared in order to switch their nonlinear optical properties between their different redox states using an electrochemical process. Firstly, ferrocenyl ruthenium alkynyl units have been studied. It has been shown that these heterobimetallic units, which are class-II mixed-valent complexes in their mono-cationic state, possess all the required electrochromic properties for their incorporation into more extended and conjugated NLO active assemblies. Then, triphenylamine- and triphenylphosphine oxide-cored octupolar complexes had been prepared. In the first case, a hexanuclear complex with six distinct redox state had been obtained whereas in the second, an ‟extended” triphenylphosphine oxide core had been developed in order to optimize their optical properties. In both cases, a marked electrochromic behavior in solution of the complexes has been observed. Finally, other organometallic dinuclear assemblies have been explored. Thus, functionalization of the ferrocenyl ruthenium alkynyl synthons with a terminal alkynyl bond has allowed the grafting of this complex onto a silicon surface, paving the way for electroswitchable materials. Alternatively, the potential of ferrocenyl ruthenium allenylidene complexes to modulate the (nonlinear) optical properties using both oxidative and reductive processes has been demonstrated
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Ibrahim, Noor Baa'yah. "Properties of yttrium iron garnet thin films grown by pulsed laser ablation deposition". Thesis, University of Warwick, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343112.
Testo completo
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Levell, Jack William. "Material and device design for organic optoelectronics". Thesis, University of St Andrews, 2011. http://hdl.handle.net/10023/2066.
Testo completoAbstract (sommario):
This thesis describes investigations into the photophysical properties of luminescent materials and their application in optoelectronic devices such as light emitting diodes and photodetectors. The materials used were all solution processable because of the interest in low cost processing of organics. I have investigated the photophysics of 1,4,5,8,9,12-hexamethyltriphenylene, a triphenylene derivative which has its luminescence enhanced by the addition of methyl groups. These groups change the planar shape of the triphenylene molecule into a twisted one, changing the symmetry of the molecule and increasing its dipole moment in absorption and emission by ~4 fold. This increased its rate of radiative deexcitation by ~20 times. In addition, the twisted shape of the molecule prevents intermolecular interactions and concentration effects from affecting the luminescence. This results in an efficient solid-state photoluminescence quantum yield of 31%. This thesis also includes an investigation into phosphorescent polymer dendrimers, designed to have suitable viscosities in solution for inkjet printed OLED applications. A photophysical study of the intra-chain aggregation effects on the luminescence was undertaken in both homopolymers and copolymers with high energy gap spacer units. Using double dendrons to increase the steric protection of the luminescent cores, the best homopolymers achieved 12.1% external quantum efficiency (39.3 cd/A) at 100 cd/m² brightness and the best co-polymer achieved 14.7% EQE (48.3 cd/A) at 100 cd/m². This compares favourably with 11.8% EQE for the best phosphorescent polymer and 16% for the best solution processed dendrimer OLED previously reported. Finally I have applied a solution processed enhancement layer to silicon photodiodes to enhance their ultraviolet response. Using a blend of materials to give favourable absorption and emission properties, 61% external quantum efficiency was achieved at 200 nm, which is better than the 20-30% typical for vacuum deposited lumogen enhancement layers used commercially.
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Colakoglu, Tahir. "The Effects Of Post-annealing Process On The Physical Properties Of Silver-indium-selenium Ternary Semiconductor Thin Films Deposited By Electron Beam Technique". Phd thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/2/12610974/index.pdf.
Testo completoAbstract (sommario):
Ternary chalcopyrite compounds are the semiconductors with suitable properties
to be used as absorber materials in thin film solar cells. AgInSe2 is a promising
candidate with its several advantages over the widely used CuInSe2. The purpose of this study was to optimize the physical properties of the Ag-In-Se (AIS)
thin films that were deposited by e-beam evaporation of Ag3In5Se9 single crystal powder for solar cell applications by means of post-annealing process under
nitrogen atmosphere. The as-grown AIS thin films were annealed at 200, 300 and 400oC and their structural, optical, electrical and photoelectrical properties were examined to
observe the effects of post-annealing process. Structural characterization of the films was performed by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) analyses. Optical properties of the films were investigated by optical transmittance measurements. Electrical and photoelectrical properties of the films were examined by temperature dependent conductivity, photoconductivity under different illumination intensities and spectral photoresponse measurements.
It was discovered that the annealing of AIS thin films at 200oC resulted in the best physical properties for solar cell applications. The obtained films were polycrystalline with mixed binary and ternary crystalline phases, such as
Ag3In5Se9, AgInSe2 and InSe, and showed n-type conductivity with room temperature conductivity value of 2.3x10-6 (Ohmcm)-1. The band gap energy of the 200oC-annealed films was determined as 1.68 eV from spectral photoresponse measurements. The results of the study revealed that the inadequate Ag incorporation and segregation and/or reevaporation of Se atoms at high annealing temperatures were the major problems encountered in producing single phase polycrystalline AgInSe2 thin films. The required stoichiometry of thin films should be maintained during the growth of the films by means of an alternative deposition procedure and the films should be selenized during post-annealing process.
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Baldo, Hurtado Bianca. "Compuestos metal-orgánicos con propiedades multifuncionales". Thesis, Rennes 1, 2018. http://www.theses.fr/2018REN1S012/document.
Testo completoAbstract (sommario):
Le fait qu'un composé métal-organique contienne à la fois une partie organique et une partie inorganique, rend ces systèmes hautement modulables, de la dimensionnalité de leur structure aux propriétés obtenues. Ainsi, la chimie de coordination a été axée sur la synthèse de nouveaux matériaux à base de cations 3d et 4f, liés par des ligands organiques avec des groupes fonctionnels de nature chimique différente, ce qui permet de trouver à ces matériaux intéressants des propriétés telles que la luminescence, l'optique non linéaire et le magnétisme. En outre, la synthèse de composés métal-organique de dimensionnalité supérieur a été dominé par les longues durées de réaction, en plus de l'utilisation de solvants organiques exposés à des conditions de température et supérieures à celles utilisées dans des procédés de synthèse classique pression. Cependant, au cours des dernières années, l'intérêt s'est accru dans le développement de nouvelles techniques de synthèse avec des temps de réaction plus courts et plus favorables à l'environnement, tels que la mécanochimie et la sonochimie. Dans cette thèse, nous présentons la synthèse, la caractérisation structurale et optique de neuf composés de coordination basés sur le liant d'imidazole-4-acide acrylique. Les composés sont classés en deux types: (1) sur la base des cations nd, à l'intérieur qui sont les précurseurs du type [M(HIA)2(H2O)4] (M = CuII, NiII, CdII et ZnII), obtenu par synthèse mécanochimique, et le polymère de coordination {[Cd(H2IA)(HIA)(H2O)2]2∙H2O(NO3)2}n obtenu par sonochimique; et (2) des composés hétérométallique nd/4f, qui sont basées sur la Cu(II)/Eu(III), Cu(II)/Gd(III), Cu(II)/Ce(III) et cations Cd(II)/Ce(IV), tous obtenus par synthèse sonochimique. Il est à noter que les composés basés sur les cations Cu(II)/Ln(III) ont également été caractérisés magnétiquement. De plus, une famille de composés à base de Ni(II)/Ln(II), obtenue par synthèse structurale est rapportéeThe fact that metal-organic compound contains an organic and an inorganic part, makes these systems highly modulable, from the dimensionality of their structure to the properties that are obtained. For this reason during the last time, the coordination chemistry has been focused on the synthesis of new materials based on 3d and 4f cations, linked through organic ligand with functional groups of different chemical nature, which contribute to obtain new materials with interesting properties such as luminescence, non-linear optics and magnetism, among others. On the other hand, the synthesis of metal-organic compounds of greater dimensionality has been dominated by long reaction times, using organic solvents exposed to conditions of temperature and pressure higher than those used in traditional synthesis methods. However, the interest for new synthetic techniques with shorter reaction times and more friendly to the environment, such as mechanochemistry and sonochemistry has grown in last years. In this thesis, are reported the synthesis, structural and optical characterization of nine coordination compounds based on the imidazole-4-acrylic acid ligand. The compounds are classified into two types: (1) based on nd cations, which are the precursors of the type [M(HIA)2(H2O)4] (with M = CuII, NiII, CdII and ZnII), obtained by mechanochemical synthesis, and also the coordination polymer {[Cd(H2IA)(HIA)(H2O)2]2·H2O(NO3)2}n obtained by sonochemistry; and (2) nd/4f heterometallic compounds obtained by sonochemical synthesis, which are based on the CuII/EuIII, CuII/GdIII, CuII/CeIII and CdII/CeIV cations. It should be noted that the compounds based on the CuII/LnIII cations were also magnetically characterized. Additionally, a family of compounds based on NiII/LnII, obtained by structural synthesis is reported. Although, the H2IA ligand does not participate in the final product, the compounds are considered novel from the structural point of view, because the Ln2+ cation, had stabilized only in organometallic compounds until now. Finally, it is important to highlight that the thesis work presented has been carried out within the framework of a co-supervision between the Université de Rennes 1, France, and the Andrés Bello University, Chile, for which two stays were made in France, with six months of duration each one. The results presented were obtained in Laboratoire ISCR Institut des Sciences Chimiques in Rennes, France, and in the Laboratorio de Compuestos Polimetálicos, Chile
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BERECZKI, ALLAN. "Desenvolvimento de um laser DPSSL polarizado com mais de 100 W de potência e parâmetro de qualidade próximo de um". reponame:Repositório Institucional do IPEN, 2016. http://repositorio.ipen.br:8080/xmlui/handle/123456789/26822.
Testo completoAbstract (sommario):
Submitted by Claudinei Pracidelli (cpracide@ipen.br) on 2016-11-11T16:24:00Z
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A operação dinamicamente estável com zonas conjuntas foi obtida para um ressonador laser contendo dois bastões de Nd:YAG com módulos laser comerciais. O ressonador não polarizado gerou 115 W de potência no modo transversal fundamental TEM00. Quando polarizado por lâmina de Brewster atingiu 100,5W de potência de saída com 91% de polarização. Quando o ressonador foi polarizado com um polarizador de filme fino, obteve-se melhora na qualidade de feixe e um aumento na polarização, com o valor de M2 sendo 1,56 e 1,84 nas direções x e y respectivamente com 95,4% de polarização. A potência de saída foi, ao nosso conhecimento, a mais alta obtida para lasers polarizados operando no modo fundamental e usando módulos lasers comerciais de Nd:YAG bombeados lateralmente por diodos sem nenhuma preparação especial.
Dissertação (Mestrado em Tecnologia Nuclear)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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Hartridge, Adrian. "Lanthanide doped ceria thin films as possible counter electrode materials in electrochromic devices". Thesis, University of Warwick, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367148.
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Silva, Francisco Nascimento. "Estudo das propriedades óptico-eletrônicas de compósitos de PVK com composto de coordenação de lantânio (III)". Universidade Federal de Mato Grosso, 2015. http://ri.ufmt.br/handle/1/704.
Testo completoAbstract (sommario):
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CAPES
Realizamos neste trabalho, estudo das propriedades ópticas e eletrônicas dos N,N’-bis(salicilidenos), com seu composto de coordenação de Lantânio (III) - La(III), em solução e em estado sólido, para avaliar seu potencial numa possível aplicação em dispositivos semicondutores orgânicos. As amostras de salicilidenos e do composto de coordenação de La(III) foram sintetizadas pela metodologia clássica. Os salicilidenos são bases de Schiff, e podem ser usados como camada ativa, dopantes ou ligantes quando coordenados a metais de transição, pois geram compostos de coordenação fluorescentes ou fosforescentes, tais como o composto de La(III). Neste trabalho foram sintetizados: N,N’-bis(salicilideno) 3,4-diaminobenzofenona-sal-3,4-benzophen (KG-21), e seu composto de La(III); bis[N,N’-bis(salicilideno)-3,4- diaminobenzofenona] lantâniato(III) de sódio, Na[La(sal-3,4- benzophen)2]; Na[La(KG-21)2]. O estudo das propriedades foi realizado através das caracterizações estrutural e fotofísica do ligante livre e de seu composto de coordenação de La(III), em soluções de Dimetilsufóxido (DMSO), Clorofórmio (CHCl3) e também em estado sólido como filmes finos usando a técnica Casting e Spin-Coating. Na caracterização estrutural utilizou-se as técnicas de espectroscopia vibracional FTIR e de espectroscopia eletrônica (UV-vis), enquanto que na caracterização fotofísica foram utilizadas as técnicas de fluorescência estacionária e resolvida no tempo. Conforme a literatura outros íons trivalentes de terras raras, Európio, Térbio e o Túlio, vem sendo utilizados, como centros emissores de luz, em dispositivos semicondutores orgânicos e, existem trabalhos que indicam a sua utilização como camada ativa eletroluminescente. Dessa forma o composto de La(III) possui boas propriedades ópticas para aplicação em dispositivos do tipo: Diodo Orgânico Emissor de Luz (OLED), Célula Solar Fotovoltaica Orgânica (OPV) e Biossensor.
We conduct at this work, the study of the optical and electronic properties of the N,N'-bis (salicylidene), with their coordination compound of lanthanum (III) - La (III), in solution and in the solid state, to evaluate its potential in a possible application in organic semiconductor devices. The samples of salicylidene and their, coordination compound of La(III); were synthesized by the classical methodology. The salicylidenes are Schiff bases and can be used as active layer, dopants or ligands; when coordinated to transition metals because they generate coordination compounds fluorescent or phosphorescent, such as compound of La(III). In this work were synthesized: N, N'-bis (salicylidene) -3,4-diaminobenzophenone - sal-3.4-benzophen (KG-21), and its compound La (III); bis[N,N'-bis(salicylidene)-3,4- diaminobenzophenone] lantâniato(III) sodium, Na[La(sal-3,4-benzophen)2]; Na[La(KG-21)2]. The study of the properties was performed out through the structural and photophysic characterization the free ligand and their coordination compounds of La(III); in solutions, dimethylsulfoxide (DMSO), Chloroform (CHCl3) and also in solid state as thin films using the technique Casting and Spin-Coating. In the structural characterization was utilized the techniques FTIR vibrational spectroscopy and electronics spectroscopy (UV-vis), whereas in the photophysical characterization techniques were used fluorescence stationary and timeresolved. According to the literature other rare earth trivalent ions, Europium, Terbium and Thulium, it has been used as light emitting centers, in organic semiconductor devices, there are studies indicating their use as active layer electroluminescent. Thus the compound of La (III) has good optical properties for use in devices of type: Organic Light Emitting Diode (OLED), solar cell Organic Photovoltaic (OPV) and Biosensor.
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Pochekailov, Sergii. "Elektrické, optické a senzorové vlastnosti organických polovodičů". Doctoral thesis, Vysoké učení technické v Brně. Fakulta chemická, 2009. http://www.nusl.cz/ntk/nusl-233292.
Testo completoAbstract (sommario):
There is big interest in cheap, sensitive and selective gas sensors. In this work, substituted soluble phthalocyanines are proposed as a sensing materials for several gases. Optical, electrical and gas sensing properties of several phthalocyanines were studied and the mechanisms of their interaction with several analyte gases are described. It was found, that sulfo-substituted Pcs has good sensitivity to humidity. Sulfonamide-substituted phthalocyanines are promising for nitrogen dioxide and volatile organic compounds detection. tert-Butyl-substituted phthalocyanines are sensitive to NO2 under higher temperature and seems to be used for environmental monitoring. Commercial gas sensors for NO2, ethanol and humidity were successfully created.
46
Doclot, Olivier. "Etude des propriétés optiques non linéaires de troisième ordre de la molécule et du cristal de 4-(N,N diéthylamino)-b-nitrostyrène par Z scan et ellipsométrie". Grenoble 1, 1996. http://www.theses.fr/1996GRE10230.
Testo completoAbstract (sommario):
Dans cette these, nous avons etudie les proprietes optiques non lineaires de troisieme ordre de la molecule et du cristal de 4-(n,n diethylamino)-nitrostyrene (deanst). Nous avons fait des mesures d'absorption a deux photons de la molecule de deanst en solution par ellipsometrie kerr. Nous avons modelise le spectre non lineaire ainsi obtenu a partir du spectre d'absorption lineaire et d'un unique parametre: la variation de moment dipolaire entre les etats s#0 et s#1. Nous avons monte un banc z scan qui permet la mesure de l'indice de refraction dependant de l'intensite et de l'absorption non lineaire aux deux longueurs d'onde 1,064 m et 532 nm. Les mesures a 1,064 m en solutions ont montre que la variation d'indice de refraction est dominee par l'effet d'orientation moleculaire et que l'absorption a deux photons est faible a cette longueur d'onde. Les mesures effectuees a 532 nm dans une bande d'absorption a un photon de la solution de deanst mettent en evidence de fortes non-linearites dues a la creation d'une population dans un etat excite. Ces mesures montrent qu'aux concentrations elevees, les molecules isolees ne sont pas les seules a jouer un role dans les proprietes non lineaires des solutions. Les mesures z scan sur le cristal de deanst revelent l'anisotropie de ses proprietes non lineaires. De plus, l'absorption non lineaire n'est pas uniquement interpretable par un phenomene de troisieme ordre et necessite l'intervention d'un coefficient non lineaire supplementaire. L'analyse des non-linearites du cristal de deanst doit etre envisagee dans le cadre d'un modele excitonique: le modele du gaz oriente en considerant une hyperpolarisabilite dominee par l'element tensoriel le long du grand axe de la molecule ne rend pas compte des non-linearites du cristal
47
HAMID-SAMIMI, MOHAMMAD-HASSAN. "Etude et caracterisation des defauts microscopiques du tellure de cadmium". Strasbourg 1, 1989. http://www.theses.fr/1989STR13009.
Testo completoAbstract (sommario):
Les niveaux des defauts dans la bande interdite du semiconducteur sont etudies ainsi que les phenomenes de transport et les proprietes optiques. On note des effets remarquables de passivation et de modification des defauts par hydrogenation
48
Souriau, Jean-Charles. "Recherche d'un matériau laser monocristallin susceptible de présenter une émission stimulée vers 1550 ou 2000 nm à température ambiante". Grenoble 1, 1993. http://www.theses.fr/1993GRE10198.
Testo completoAbstract (sommario):
Les applications des lasers susceptibles d'emettre a temperature ambiante dans la zone de securite oculaire autour de 1550 et 2000 nm sont tres nombreuses: telemetrie, altimetrie, anemometrie. . . L'obtention de ces lasers peut etre realisee par le dopage de matrices transparentes par les ions terres rares er#3#+, tm#3#+ et ho#3#+. Ceux-ci presentent respectivement une transition radiative vers 1550, 2000 et 2100 nm. Cependant les interactions entre ces ions conduisent a des mecanismes qui diminuent les rendements laser dans l'infrarouge. L'objet de cette these est de decouvrir de nouvelles matrices monocristallines permettant d'accueillir les ions cites ci-dessus et presentant, a la fois de bonnes proprietes thermomecaniques et des performances laser interessantes. Les proprietes luminescentes d'une vingtaine de matrices polycristallines dopees ont ete etudiees. A l'issue de cette etude, plusieurs d'entre elles ont ete selectionnees. L'elaboration sous forme monocristalline par la methode de tirage czochralski a pu etre realisee pour les systemes suivants: y#2sio#5, cayalo#4 et sry#4(sio#4)#3o dopes avec les ions er#3#+ et codopes yb#3#+-er#3#+ (l'ion yb#3#+ jouant le role de sensibilisateur) et pour les matrices y#2sio#5 et sry#4(sio#4)#3o dopees avec les ions tm#3#+. Une caracterisation approfondie des proprietes optiques de ces materiaux est presentee dans cette these. Enfin, nous avons demontre pour la premiere fois un effet laser a temperature ambiante, a 1576 nm dans un cristal de y#2sio#5:yb#3#+-er#3#+ et a 1554 nm dans un cristal de sry#4(sio#4)#3o:yb#3#+-er#3#+. Ce sont les seuls systemes monocristallins presentant une emission laser aussi proche de la fameuse longueur d'onde 1550 nm. De meme, le premier effet laser a 1988 nm a ete montre dans le systeme sry#4(sio#4)#3o:tm#3#+. Ces performances laser ont ete comparees a d'autres systemes et en particulier a celles du y#2sio#5:tm#3#+
49
Nouvelot, Luc. "Evaluation et réalisation de miroirs diélectriques à profil d'indice continu et périodique (filtres rugates)". Grenoble 1, 1993. http://www.theses.fr/1993GRE10069.
Testo completoAbstract (sommario):
Differentes methodes de calcul des proprietes optiques des couches minces optiques a profil d'indice continu sont presentees. Dans le cas des filtres rugates, l'utilisation de methodes analytiques a notamment permis un calcul des enveloppes des spectres ainsi que l'optimisation du profil d'indice. Un nouveau systeme de coevaporation sous vide a ete developpe pour realiser des filtres a profil d'indice continu. Des couches minces homogenes de zns, znse, mgf#2, ainsi que de zns-mgf#2 et de znfe-mgf#2 de differentes compositions ont ete realisees. Il apparait que le zns presente un probleme de condensation lorsqu'il est codepose avec du mgf#2, meme sur substrat froid. Le znse ne presente pas ce probleme lorsque celui-ci est majoritaire dans un melange realise a froid. Des filtres rugates a profil d'indice sinusoidal, comportant jusqu'a 20 periodes, ont ete realises en znse-mgf#2 depose sur substrat froid. Leurs spectres de reflexion et de transmission sont conformes aux simulations numeriques. Un atout important des filtres rugates par rapport aux multicouches a par ailleurs ete mis en evidence: les faibles contraintes dans les couches de melanges znse-mgf#2 et dans les filtres realises devraient autoriser la realisation de films epais, ce qui est une necessite pour la realisation de miroirs de faible largeur de bande
50
SENCE, MARTINE. "Etude des proprietes optiques du seleniure de cadmium sous hautes intensites d'excitation lumineuse". Université Louis Pasteur (Strasbourg) (1971-2008), 1989. http://www.theses.fr/1989STR13021.
Testo completoAbstract (sommario):
Etude des caracteristiques du plasma electron-trou. Interpretation des courbes de gain optique obtenues par deux modeles theoriques. Etude des proprietes des biexcitons par melange degenere a quatre ondes et determination de leur energie de liaison (2 mev)