Um die anderen Arten von Veröffentlichungen zu diesem Thema anzuzeigen, folgen Sie diesem Link: Transparentní materiál.
Dissertationen zum Thema „Transparentní materiál“
Geben Sie eine Quelle nach APA, MLA, Chicago, Harvard und anderen Zitierweisen an
Machen Sie sich mit Top-50 Dissertationen für die Forschung zum Thema "Transparentní materiál" bekannt.
Neben jedem Werk im Literaturverzeichnis ist die Option "Zur Bibliographie hinzufügen" verfügbar. Nutzen Sie sie, wird Ihre bibliographische Angabe des gewählten Werkes nach der nötigen Zitierweise (APA, MLA, Harvard, Chicago, Vancouver usw.) automatisch gestaltet.
Sie können auch den vollen Text der wissenschaftlichen Publikation im PDF-Format herunterladen und eine Online-Annotation der Arbeit lesen, wenn die relevanten Parameter in den Metadaten verfügbar sind.
Sehen Sie die Dissertationen für verschiedene Spezialgebieten durch und erstellen Sie Ihre Bibliographie auf korrekte Weise.
1
Hykolli, Denis. „Jednostupňová převodovka vyrobená 3D tiskem“. Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2021. http://www.nusl.cz/ntk/nusl-443218.
Der volle Inhalt der QuelleAnnotation:
The aim of these theses was the creation of a single-stage gearbox by additive technology FDM / FFF. By chosen values was made dimension calculation for gears. The 3D model of the gearbox was designed in 3D software Autodesk Inventor. Single parts were produced on an FDM 3D printer by Prusa Research. Manufacturing programs for parts were prepared in PrusaSlicer. These programs were used for producing individuals parts on 3D Printer. Transparent material and printing parameters for the top of the gearbox were chosen by visual test and test of light intensity. The total cost of model production is calculated in the work. The result of these is a completely working model of a single-stage gearbox with a transparent top of the gearbox.
2
Tásler, Jan. „Příprava a vlastnosti transparentních polykrystalických keramických materiálů“. Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-416665.
Der volle Inhalt der QuelleAnnotation:
The presented diploma thesis is focused on the preparation and properties of transparent polycrystalline ceramic materials based on Al2O3. Theoretically, the most important technological aspects of the processing of these materials are presented. Detailed attention is given to transparent Al2O3 polycrystalline ceramics doped with rare earth elements. The influence of microstructural parameters on the optical properties (represented by RIT) is investigated on Al2O3 samples doped and codoped with dysprosium, terbium and chromium. A significant effect of the average grain size on the light transmittance of all samples is observed. The highest RIT = 55 % (measured by a laser beam with a wavelength of 632,8 nm) was achieved by an optimized preparation process for a sample doped with 0,05 at. % of dysprosium. For all samples photoluminescent properties are also analysed. The photoluminescent emission spectra correspond to the activation of doping elements. In case of the terbium and chromium codoped samples, the differences in the activation of individual dopants depending on different excitation wavelengths were demonstrated, resulting in different colour emissions for different excitation wavelengths.
3
Martin, Alexis. „Conception et étude d'antennes actives optiquement transparentes : de la VHF jusqu'au millimétrique“. Thesis, Rennes 1, 2017. http://www.theses.fr/2017REN1S126/document.
Der volle Inhalt der QuelleAnnotation:
Avec le développement de l’internet des objets et l’augmentation des applications sans fil, les antennes sont de plus en plus présentes au quotidien. Cependant, l’implantation de ces antennes est un challenge tant d’un point de vue technologique (intégration des antennes dans les dispositifs), que psychologique (acceptabilité des antennes par le grand public). Dans ce contexte, le développement d’antennes optiquement transparentes permet non seulement leur implantation sur de nouvelles surfaces (vitrages d’immeubles, écrans de smartphones ...), mais promeut aussi leur acceptabilité par le grand public grâce à leur faible impact visuel. Ce travail présente la conception, la fabrication et la caractérisation d’antennes actives optiquement transparentes. Le matériau transparent et conducteur utilisé est un maillage métallique à pas micrométrique développé spécifiquement, alliant conductivité électrique et transparence optique élevées. Dans ce cadre, un premier prototype d’antenne transparente et miniature en bande FM utilisant un transistor MESFET de dimensions sub-millimétriques a été réalisé. Des antennes agiles en fréquence en bande X (~10 GHz) couplées, soit à une diode varicap localisée (agilité ~10%), soit à un matériau ferroélectrique (agilité ~2%), ont été développées et étudiées. Une antenne passive transparente a été conçue en bande V (~60 GHz). Enfin, une transition optique (1540 nm) / hyperfréquence (1,4 GHz) a été réalisée et caractérisée, basée sur la transmission optique d’un faisceau laser au travers du matériau constitutif de l’antenne. Pour l’ensemble des prototypes réalisés, une transparence optique supérieure à 80% dans le domaine du visible associée à une résistance par carré inférieure à 0,1 ohm/sq ont été utiliséesWithin the development of the Internet of Things (IoT) and the increase of the wireless communications, antennas are even more present on everyday life. However, antenna implementation is a real challenge, from a technological point of view (antenna integration into the devices) and from a psychological point of view (acceptability by the general public). Within this framework, the development of optically transparent antennas on new surfaces (glass windows, smartphone screens . . . ) is of great interest to improve the network coverage and to assist the general public in acceptability thanks to the low visual impact of such printed antennas. The present work deals with the design, the fabrication and the characterization of optically transparent and active antennas. The transparent and conducting material used is a micrometric mesh metal film specifically developed, associating high electrical conductivity and high optical transparency. A first optically transparent and miniature FM antenna based on a MESFET transistor with micrometric size has been designed and fabricated. Frequency agile antennas operating in X-band (~10 GHz), based on a beam-lead varactor (agility ~10%) and on a ferroelectric material agility ~2%), have been developed and characterized. An optically transparent and passive antenna has been studied in V-band (~60 GHz). At last, optics (1540 nm) / microwave (1.4 GHz) transition has been performed based on the transmission of a laser beam through the transparent antenna. For all prototypes, an optical transparency level higher than 80% coupled with a sheet resistance value lower than 0.1 ohm/sq have been used
4
Colucci, Renan [UNESP]. „Desenvolvimento de um compósito contendo polímero condutor (PEDOT:PSS) e material ORMOSIL (GPTMS) com aplicação na fabricação de dispositivos eletroluminescentes“. Universidade Estadual Paulista (UNESP), 2016. http://hdl.handle.net/11449/141509.
Der volle Inhalt der QuelleAnnotation:
Submitted by Renan Colucci null (37412942840) on 2016-07-12T19:19:53Z
No. of bitstreams: 1
dissertação_RENAN_versãofinal.pdf: 3242692 bytes, checksum: c7bf17a6e3f70f7b97cb6c8ecfa1e065 (MD5)Approved for entry into archive by Ana Paula Grisoto (grisotoana@reitoria.unesp.br) on 2016-07-15T16:29:02Z (GMT) No. of bitstreams: 1 colucci_r_me_rcla.pdf: 3242692 bytes, checksum: c7bf17a6e3f70f7b97cb6c8ecfa1e065 (MD5)
Made available in DSpace on 2016-07-15T16:29:02Z (GMT). No. of bitstreams: 1 colucci_r_me_rcla.pdf: 3242692 bytes, checksum: c7bf17a6e3f70f7b97cb6c8ecfa1e065 (MD5) Previous issue date: 2016-06-27
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Atualmente é possível fabricar dispositivos eletroluminescentes (EL) utilizando como material ativo uma dispersão de um pó eletroluminescente inorgânico em uma matriz polimérica condutora. Entretanto, esses materiais são quimicamente instáveis, o que impede a deposição de alguns materiais solúveis sobre eles, como por exemplo, eletrodos de tinta prata. Para solucionar este problema, desenvolvemos uma matriz condutora e quimicamente estável formada pelo polímero condutor poli(3,4-etileno dioxitiofeno):poliestireno sulfonado (PEDOT:PSS) e pelo material sílica-orgânico 3-glicidoxipropil trimetilsilano (GPTMS). Foram produzidos compósitos de PEDOT:PSS/GPTMS com diversas concentrações de PEDOT:PSS, com os quais foram produzidos filmes uniformes, insolúveis e com condutividade elétrica entre 2 S/cm e 400 S/cm. A dependência da condutividade elétrica destes materiais em função da temperatura e da concentração de PEDOT:PSS foi descrita pelo modelo de transporte de cargas variable range hopping (VRH-3D). Adicionando-se o material eletroluminescente (EL) inorgânico silicato de zinco dopado com manganês (Zn2SiO4:Mn) à matriz condutora de PEDOT:PSS/GPTMS foi obtido um compósito para a produção de dispositivos EL. Depositando-se este compósito EL sobre substratos de vidro contendo eletrodos transparentes de óxido de estanho e índio, foram obtidos dispositivos EL com tensão de operação de 30 V e eficiência luminosa de 1,3 cd/A. Além disso, a transmitância óptica e a resistência de folha de filmes do compósito condutor (PEDOT:PSS/GPTMS) foram avaliadas, demonstrando que este material apresenta propriedades compatíveis com a aplicação como eletrodo transparente. Por fim, foram produzidos dispositivos EL utilizando o compósito condutor PEDOT:PSS/GPTMS como eletrodos e o compósito EL PEDOT:PSS/GPTMS/ Zn2SiO4:Mn como material ativo. Com este experimento, foi demonstrada a possibilidade de fabricar dispositivos EL por rota líquida, onde o compósito PEDOT:PSS/GPTMS foi utilizado tanto para a fabricação dos eletrodos como para a produção do material ativo do dispositivo.
It is possible to fabricate light-emitting (LE) devices with LE composites as active material. These light-emitting composites are produced with a LE inorganic powder dispersed into a conducting polymer matrix. However, these composites are chemically unstable, limiting the deposition of soluble materials over it. To overcome this problem we developed a high-stability conductive matrix comprising the conductive polymer poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) and the organic-silicate 3-glycidyloxypropyl)trimethoxysilane (GPTMS). Composites PEDOT:PSS/GPTMS with diverse weight concentrations of PEDOT:PSS were produced and used to fabricate high-stability films with electrical conductivity from 2 S/cm up to 400 S/cm. The charge transport in these conductive composites were studied as function of the temperature, as well as of the PEDOT:PSS concentration, and described by the 3D variable range hopping model. A light-emitting composite was produced adding to this conductive composite the inorganic electroluminescent powder Mn-doped zinc silicate (Zn2SiO4:Mn). Light-emitting devices, with turn-on voltage of 30 V and luminous efficacy of 1.3 cd/A, were produced with a coating of the developed LE composite done over glass substrates containing indium tin oxide transparent electrodes. Additionally, the optical transmittance and sheet resistance of films produced with the conductive composite PEDOT:PSS/GPTMS were evaluated showing that this material is suitable to fabricate transparent electrodes. Finally, were produced light-emitting devices employing the conductive composite PEDOT:PSS/GPTMS as electrodes and the light-emitting composite PEDOT:PSS/GPTMS/ Zn2SiO4:Mn as active material. This experiment has shown the fabrication of solution-processed light-emitting devices using the composite PEDOT:PSS/GPTMS as transparent electrode and as component of the active material.
5
Polster, Steffen. „Laserdurchstrahlschweissen transparenter Polymerbauteile“. Bamberg Meisenbach, 2009. http://d-nb.info/995566216/04.
Der volle Inhalt der Quelle
6
Yang, Weijia. „Femtosecond laser writing in transparent materials“. Thesis, University of Southampton, 2008. https://eprints.soton.ac.uk/65510/.
Der volle Inhalt der QuelleAnnotation:
Optical waveguides (type-I), with perfect mode matching to the standard single-mode fibre and with an overall insertion loss of ~1 dB, have been demonstrated in high index bismuth borate glass by femtosecond laser direct writing. Broadening of the transmitted light source by as much as 500 nm was demonstrated through a waveguide with a length of 1.8 cm. Finally, passive waveguide components such as Y-splitters and directional couplers have also been fabricated using this writing technique. Self-assembled, sub-wavelength periodic structures (type-II) are induced in fused silica by a tightly focused, linearly polarized, femtosecond laser beam. Two different types of periodic structures, the main one with period (ΛE) in the direction of the laser beam polarization and the second with period (Λk) in the direction of the light propagation, are identified from the cross-sectional images of the modified regions using scanning electron microscopy. The period ΛE is proportional to the wavelength of the writing laser and the period Λk in the head of the modified region remains approximately the wavelength of light in fused silica. A new phenomenon in ultrafast laser processing of transparent optical materials, in particular silica glass, manifested as a change in material modification by reversing the writing direction, is observed. The effect resembles writing with a quill pen and is interpreted in terms of new physical effect - anisotropic trapping of electron plasma by a tilted front of the ultrashort laser pulse. Different types of modifications are induced in fused silica by controlling the pulse front tilt. Birefringent modification is demonstrated in the chalcogenide glass by femtosecond laser direct writing. The optical axis of the birefringent region is not determined by the laser polarization direction. It is observed that the information on the direction of writing can be recorded and be rewritable in the chalcogenide glass. Finally, a unique non-reciprocal photosensitivity is identified for the lithium niobate crystal for ultrafast laser direct writing. Therefore, in a non-centrosymmetric medium, modification of the material can be different when light propagates in opposite directions.
7
Avelas, Resende Joao. „Copper-based p-type semiconducting oxides : from materials to devices“. Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAI072/document.
Der volle Inhalt der QuelleAnnotation:
L'absence d'oxydes semi-conducteurs de type p de haute performance retarde le développement de d’électronique transparente et du photovoltaïque à base d’oxydes. Dans le groupe des composés semi-conducteurs, les oxydes à base de cuivre présentent des caractéristiques électriques, optiques et de fabrication prometteuses qui établissent cette famille de matériaux comme bien adaptés aux applications semi-conductrices de type p. Dans ce travail, nous nous concentrons sur la croissance de films minces d’une part de Cu2O dopée par des cations et d’autre part de CuCrO2, visant à améliorer leurs propriétés optiques et électriques. De plus, nous avons mis en œuvre ces films d'oxyde dans des dispositifs de jonction pn tels que des cellules solaires et des photodétecteurs UV.Dans le travail sur Cu2O, nous avons réalisé l'incorporation de magnésium jusqu'à 17% dans des films minces par dépôt chimique en phase vapeur assisté par aérosol, entraînant des changements de morphologie. La résistivité électrique a été réduite jusqu’à des valeurs de 6,6 ohm.cm, en raison de l'augmentation de la densité de porteur de-charges jusqu'à 10^18 cm-3. L'incorporation du magnésium a en outre eu un impact sur la stabilité de la phase Cu2O. En effet la transformation du Cu2O en CuO en conditions oxydantes est considérablement retardée par la présence de Mg dans les films, en raison de l'inhibition de la formation d’un type particulier de lacune de cuivre (split vacancy). L'intégration dans les jonctions pn a été réalisée avec succès en utilisant uniquement des voies de dépôt chimique en phase vapeur, en combinaison avec le ZnO de type n. Néanmoins, l'application de Cu2O dopé au Mg dans les cellules solaires présente un effet photovoltaïc très faible, loin des meilleures valeurs de l’état de l’art.Dans le travail sur CuCrO2, nous démontrons la première fabrication d'hétérostructures de nanofils en configuration cœur/coquille ZnO/CuCrO2 utilisant des techniques de dépôt chimique adaptées pour des grandes surface, à faible coût, facilement implémentées à des températures modérées et leur intégration dans des photodétecteurs UV auto-alimentés. Une coquille conforme de CuCrO2 avec la phase de delafossite et avec une uniformité élevée a été élaborée par un dépôt chimique en phase vapeur assisté par aérosol sur un réseau de nanofils ZnO alignés verticalement, obtenu par dépôt par bain chimique. Les hétérostructures ZnO/CuCrO2 coeur-coquille présentent un comportement rectificatif significatif, avec un ratio de rectification maximal de 5500 à ± 1V, ce qui est bien meilleur que les dispositifs 2D similaires rapportés dans la littérature, ainsi qu'une absorption élevée supérieure à 85% dans la région UV. Lorsqu'ils sont appliqués en tant que photodétecteurs UV auto-alimentés, les hétérojonctions optimisées présentent une réponse maximale de 187 μA / W sous une polarisation nulle à 374 nm ainsi qu'une sélectivité élevée avec un ratio de rejet entre l’UV-et le visible (374-550 nm) de 68 sous irradiance de 100 mW/cm2The lack of a successful p-type semiconductor oxides delays the future implementation of transparent electronics and oxide-based photovoltaic devices. In the group semiconducting compounds, copper-based oxides present promising electrical, optical and manufacturing features that establish this family of materials suitable for p-type semiconductor applications. In this work, we focused on the growth of cation doped Cu2O and intrinsic CuCrO2 thin films, aiming for enhancements of their optical and electrical response. Furthermore, we implemented these oxide films into pn junction devices, such as solar cells and UV photodetectors.In the work on Cu2O, we achieved the incorporation of magnesium up to 17% in thin films by aerosol-assisted chemical vapor deposition, resulting in morphology changes. Electrical resistivity was reduced down to values as low as 6.6 ohm.cm, due to the increase of charge-carrier density up to 10^18 cm-3. The incorporation of magnesium had additionally an impact on the stability of the Cu2O phase. The transformation of Cu2O into CuO under oxidizing conditions is significantly postponed by the presence of Mg in the films, due to the inhibition of copper split vacancies formation. The integration into pn junctions was successfully achieved using only chemical vapor deposition routes, in combination with n-type ZnO. Nevertheless, the application of Mg-doped Cu2O in solar cells present a meager photovoltaic performance, far from the state-of-the-art reports.In the work on CuCrO2, we demonstrate the first fabrication of ZnO/CuCrO2 core-shell nanowire heterostructures using low-cost, surface scalable, easily implemented chemical deposition techniques at moderate temperatures, and their integration into self-powered UV photodetectors. A conformal CuCrO2 shell with the delafossite phase and with high uniformity is formed by aerosol-assisted chemical vapor deposition over an array of vertically aligned ZnO nanowires grown by chemical bath deposition. The ZnO/CuCrO2 core-shell nanowire heterostructures present a significant rectifying behavior, with a maximum rectification ratio of 5500 at ±1V, which is much better than similar 2D devices, as well as a high absorption above 85% in the UV region. When applied as self-powered UV photodetectors, the optimized heterojunctions exhibit a maximum responsivity of 187 µA/W under zero bias at 374 nm as well as a high selectivity with a UV-to-visible (374-550 nm) rejection ratio of 68 under an irradiance of 100 mW/cm2
8
Noriega, Motta Julio Amilcar. „Portable transparent indenter instrumentation for material surface characterization“. Morgantown, W. Va. : [West Virginia University Libraries], 2006. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=4765.
Der volle Inhalt der QuelleAnnotation:
Thesis (Ph. D.)--West Virginia University, 2006.Title from document title page. Document formatted into pages; contains xiii, 105 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 97-98).
9
Alston, M. E. „Biologically inspired transparent material as an energy system“. Thesis, University of Salford, 2017. http://usir.salford.ac.uk/44731/.
Der volle Inhalt der QuelleAnnotation:
Glazed envelopes on buildings play a major role in operational energy consumption as they define the boundary conditions between the climate outside and the thermal comfort inside a building. Glass façades are viewed as an uncontrolled load that sets the operational performance requirements for air-cooling mechanical systems. These façades are determined by code compliant performance levels set by a single prescriptive static, the U value. This is energetically weak, a dynamic IR absorber strategy is needed, since performance requires change by the hour, season, and weather conditions to sync with a warming earth atmosphere. A transparent dynamic IR absorber , will be modulated by temperature-dependance of the absorber by active tailored flows in a microfluidic based platform, than conventional IR static absorbers. Nature’s characterization of materials is a thermally dynamic response in real time to a microenvironment. This functionality of heat seeking materials would advance a transparent material by energy capture and storage. The hypothesis demonstrates nature’s use of fluidics to direct the structural assembly of a polymer into a thermally functional device, to actively regulate solar radiation as an IR absorber, to lower the polymer device phase transition temperature. This research determines this functionality by hierarchical multi micro-channel network scaling, as a leaf resistor. Resistor conduit analysis defines flow target resistance through simulation to generate a multi micro-channel network, for enhanced solar radiation absorption. This is demonstrated by precise hydrodynamic control in a network using switching of water flow as a thermal switching medium to regulate heat transport flow. Nature evaluates heat flow transport in real time that is not emulated in current glass façade static performance. The knowledge gap is therefore to advance a transparent material from a static function, to a dynamic IR absorber for solar modulation, and this is demonstrated in this research.
10
Santos, Joaquim Cesar Pizzutti dos. „Desempenho térmico e visual de elementos transparentes frente à radiação solar“. Universidade de São Paulo, 2002. http://www.teses.usp.br/teses/disponiveis/88/88131/tde-22092016-152800/.
Der volle Inhalt der QuelleAnnotation:
A especificação das vedações transparentes é uma das decisões mais complexas no âmbito do projeto arquitetônico. Envolve diversos fatores construtivos e de necessidades humanas relacionadas ao conforto ambiental, associadas a uma grande variedade de produtos disponíveis no mercado. Este trabalho busca facilitar aos projetistas esse processo de especificação, fornecendo valores dos parâmetros de desempenho dos elementos transparentes em relação à análise do conforto térmico e visual, coerentes com a realidade climática brasileira e com a real incidência da radiação solar ao longo do dia. Foram estudados os vidros comuns, laminados e refletivos, e as películas de controle solar, policarbonatos e acrílicos usados em edificações no Brasil. Foi utilizada a análise por espectrofotometria para a obtenção dos valores de refletância, transmitância a absortância para as diferentes regiões do espectro solar, com ângulos de incidência variados. A partir do relacionamento desses resultados, considerando o comportamento similar de variação do Fator do Calor Solar (FCS) e da Transmitância da Luz Visível (Tv) com o ângulo de incidência, foi desenvolvida uma metodologia que possibilita o cálculo simplificado de ganhos de calor e luz natural.The specification of the transparent elements is one of the most complex decisions in the ambit of the architectural project. It involves several constructive factors and human necessities related to the environmental comfort, associated to a great variety of available products in the market. The aim of this work is to facilitate the specification process to the planners, supplying values of the performance parameters of the transparent elements in relation to the analysis of thermal and visual comfort, coherent with the Brazilian climatic reality and with real incidence of the solar radiation along of the day. It were studied the ordinary, laminate and reflective glasses, the solar control films, policarbonates and acrylic used in Brazilian constructions. The spectrophotometry analysis was used to obtain the reflectance, the transmittance and the absortance values for the different regions of the solar spectrum, with varied incidence angles. Starting from the relationship of those results, considering the similar behavior of variation of the Solar Heat Factor (FCS) and of Transmittance of the Visible Light (Tv) with the incidence angle, it was developed a methodology that facilitates the simplified calculation of heat and natural light gains.
11
Zófoli, Giana da Rocha. „CONTRIBUIÇÃO TERMO-ENERGÉTICA DOS FECHAMENTOS TRANSPARENTES EM EDIFÍCIOS COMERCIAIS CLIMATIZADOS ARTIFICALMENTE EM SANTA MARIA-RS“. Universidade Federal de Santa Maria, 2011. http://repositorio.ufsm.br/handle/1/7781.
Der volle Inhalt der QuelleAnnotation:
This paper analyzes the influence of the penetration of solar radiation through the
transparent closure in consumption of energy for conditioning of the office buildings
in the region of Santa Maria-RS, located in the bioclimatic Brazilian zone 2. To do
this, simulations were performed in the computational program Design Builder, in a
typical office environment in order to evaluate the comparative results obtained with
the use of different types of glass (Solar Factor) by different percentages of area of
windows and surface guidelines. The glasses used had solar factor ranging from
0.85, 0.70, 0.56 and 0.29, an opening percentage area of 20%, 50% and 80%, while
the solar orientation ranged from 0° to 315° at an interval of 45°. It was observed that
for the climate of the city of Santa Maria-RS, considering the daytime use of the
building, the consumption of energy for cooling process has higher values compared to
the heating and that this difference is directly proportional to the solar factor of the
glass and the percentage of openings in the facade. Changes that contribute to a
reduction of one of these lead to an increased consumption of the other, these should
be analyzed jointly in the process of defining the openings, in order to obtain the lowest
annual energy consumption. The simulations indicated higher expenditure of energy
with heating on the facades oriented to the south, southeast, and southwest, while the
higher cost for cooling occurred on facades oriented to the north, northeast, northwest,
regardless of the solar factor or percentages of openings in façade. It was observed
that, when established constructive guidelines regarding apertures in construction
performance standards for buildings, should be considered together the percentage
of area openings, Factor Solar glass and solar orientation of the facade, as the
exchanges of heat and entry lighting are naturally associated with these factors in an
integrated manner.Este trabalho analisa a influência da radiação solar que penetra pelos fechamentos transparentes no consumo de energia para climatização de edifícios de escritório na região de Santa Maria RS, situado na zona bioclimática 2 brasileira. Para isso, foram realizadas simulações no programa computacional Design Builder, em um ambiente típico de escritório, visando avaliar comparativamente os resultados obtidos com o uso de diferentes tipos de vidro (Fator Solar), mediante diferentes percentuais de área de janelas e orientações de fachada. Os vidros utilizados têm valores de Fator Solar variando de 0.85, 0.70, 0.56 e 0.29, o percentual de área de abertura de 20%, 50% e 80%, enquanto a orientação solar variou de 0° a 315°, com intervalo de 45°. Foi observado, para o clima da cidade de Santa Maria-RS, considerando-se o uso diurno do edifício, que o consumo de energia para resfriamento apresenta valores mais elevados em relação ao aquecimento, e que esta diferença é diretamente proporcional ao Fator Solar do vidro e ao percentual de aberturas na fachada. Mudanças que colaboram para a redução de um destes consumos levam ao aumento do outro, devendo-se analisá-los de forma conjunta, no processo de definição das aberturas, para que se obtenha o menor consumo anual de energia. As simulações indicaram maiores gastos de energia com aquecimento nas fachadas orientadas para sul, sudeste e sudoeste, enquanto os maiores gastos com resfriamento ocorrem com fachadas orientadas a norte, nordeste e noroeste, independente do Fator Solar do vidro ou do percentual de aberturas na fachada. Foi observado que, ao serem estabelecidas diretrizes construtivas referentes a aberturas em normas de desempenho de edificações, devem ser considerados conjuntamente o percentual de área de aberturas, o Fator Solar do vidro e a orientação solar da fachada, pois as trocas de calor e entrada de iluminação natural estão associadas a estes fatores de forma integrada.
12
Terborg, Roland A. „Lens-free interferometric microscope for transparent materials“. Doctoral thesis, Universitat Politècnica de Catalunya, 2018. http://hdl.handle.net/10803/663758.
Der volle Inhalt der QuelleAnnotation:
As health systems fight against epidemics and infectious diseases, new forms of diagnostics need to be developed in order to meet the growing demand for services, often in locations without the necessary infrastructure. An emerging solution to this problem is point of care (POC) devices since they can provide rapid diagnostics without the need for specialized personnel or complex infrastructures.
In this thesis, we show the development of a POC platform for the rapid early detection of infection, in particular Sepsis, a whole-body inflammatory reaction with high mortality rates. The main components of this platform are: a lens-free interferometric microscope (LIM) and a microfluidic cartridge with a functionalized plasmonic chip for the label-free detection of biomarkers. The LIM is also able to measure the phase modulation in commercial plasmonic chips.
More specifically the thesis describes:
• The development of a LIM with a large field of view and depth of field showing a sensitivity of 1nm along the beam propagation axis, which allows, for instance, the measurements of ultra-thin (2nm thickness) transparent silica and protein monolayer microarrays.
• The generation of periodic structured light beams, obtained using a simple configuration including the birefringent elements of the LIM. These can be applied not only to imaging and biomarker detection but also in additive manufacturing and micro-structuring of surfaces.
• The phase measurement of commercial surface plasmon resonance chips for the detection of changes in the refractive index of liquids. The phase measurements provide a sensitivity for bulk refractive index changes that is about one order of magnitude larger than for intensity-based detection under similar conditions. These results show a potential enhancement of the sensitivity of standard systems used in the biomedical community.
• The development of a POC device comprising the LIM as a reader of specifically designed plasmonic gold nanohole array chips. The reading of the phase signal in the LIM shows a sensitivity increased by one order of magnitude thanks to the enhanced localized surface plasmon resonance interaction. Low concentrations of proteins and bacteria (as low as a single unit) are detected in measurements that also include human samples. This platform has the potential to multiplex the signal for simultaneous detection of thousands or even millions of different biomarkers.
The LIM presented in this thesis is a very sensitive and robust imaging system with a high performance level for the detection of small quantities of transparent materials, with applications in microscopy and biomedicine.A medida que los sistemas de salud combaten epidemias y enfermedades infecciosas, nuevas formas de diagnóstico deben desarrollarse para satisfacer la creciente demanda de servicios, a menudo en lugares sin la infraestructura necesaria. Una solución emergente a este problema son los dispositivos de punto de atención (POC por sus siglas en inglés) ya que pueden proporcionar un diagnóstico rápido sin la necesidad de personal especializado o infraestructura compleja. En esta tesis mostramos el desarrollo de una plataforma POC para la detección rápida y temprana de infecciones, en particular Sepsis, una reacción inflamatoria de todo el cuerpo con altas tasas de mortalidad. Los principales componentes de esta plataforma son: un microscopio interferométrico sin lentes (LIM por sus siglas en inglés) y un cartucho de microfluídica con un chip plasmónico funcionalizado para la detección de biomarcadores, libre de marcadores adicionales. El LIM es también capaz de medir la modulación de fase en chips plasmónicos comerciales. Más específicamente, la tesis describe: * El desarrollo del LIM con un gran campo de visión y profundidad de campo mostrando una sensibilidad de 1nm a lo largo del eje de propagación del haz, que permite, por ejemplo, las mediciones de microarreglos ultrafinos (grosor de 2nm) y transparentes de Sílica y de monocapas de proteína.* La generación de haces de luz estructurados periódicos, obtenidos usando una configuración simple que incluye los elementos birrefringentes del LIM. Estos pueden ser aplicados no sólo a la detección de imágenes y biomarcadores, sino también a la fabricación aditiva y microestructuración de superficies. * La medición de fase en chips comerciales por resonancia de plasmón superficial para la detección de cambios en el índice de refracción de líquidos. Las mediciones de fase proporcionan una sensibilidad para cambios de índice de refracción en bulto que es aproximadamente un orden de magnitud mayor que para la detección basada en la intensidad con condiciones similares. Estos resultados muestran una potencial mejora de la sensibilidad de los sistemas estándar utilizados en la comunidad biomédica. * El desarrollo de un dispositivo POC que comprende el LIM como lector de chips plasmónicos de oro con arreglos de nano-agujeros específicamente diseñados. La lectura de la señal de fase en el LIM muestra un aumento de un orden de magnitud en la sensibilidad gracias a la interacción mejorada por la resonancia de plasmón superficial localizado. Bajas concentraciones de proteínas y bacterias (tan bajas como una sola bacteria) se detectan en mediciones que también incluyen muestras humanas. Esta plataforma tiene el potencial de multiplexar la señal para la detección simultánea de miles o incluso millones de biomarcadores diferentes. El LIM presentado en esta tesis es un sistema de imagen muy sensible y robusto con un alto nivel de rendimiento para la detección de pequeñas cantidades de materiales transparentes, con aplicaciones en microscopía y biomedicina.
13
Modoran, Georgia C. „Intense field electron excitation in transparent materials“. Columbus, Ohio : Ohio State University, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1133273960.
Der volle Inhalt der Quelle
14
Narayanan, Sudarshan. „Metal-Polymer Hybrid Materials for Flexible Transparent Conductors“. Research Showcase @ CMU, 2014. http://repository.cmu.edu/dissertations/469.
Der volle Inhalt der Quelle
15
Wang, Yi. „Mechanical performance of transparent laminated materials for aircraft“. Thesis, Imperial College London, 2016. http://hdl.handle.net/10044/1/59698.
Der volle Inhalt der QuelleAnnotation:
To fully understand mechanical and structural performance of laminated glass, seven laminated cases were designed to assess the influence of glass types, polymer interlayer thickness, polymer interlayer types and multi-layered interlayer. An innovative apparatus combining 3D-Digital-Image-Correlation and ring on ring tests have been tested successfully, major strain and out of plane displacement at the supporting side were monitored. Novel sabot design helped the rubber projectile to eject without deformation in gas gun tests. The third innovative design was the gas gun system which allowed a stereo system of two high speed cameras for 3D-Digital-Image-Correlation and one camera monitoring impact performance, strain gauge system, and detecting velocity to be synchronised at the same time. Regarding major research findings, for monolithic glasses, an approximate 0.8% major failure strain was identified regardless of its thickness which was used as a failure criterion for laminated glass. For laminated glasses, an increase of thermoplastic-polyurethane thickness will allow laminate to absorb more energy at quasi static and low velocity ranges, but lower the supporting face strain at high velocity. Chemically strengthened glass used as frontal glass layer has better performance in terms of energy consumption in quasi static and low velocity ranges comparing to thermally strengthened glass. Different types of interlayer have different functionalities. Sentry-glass-plus is more rigid comparing thermoplastic-polyurethane and polyvinyl-butyral which can transfer more shear between layers and lower the strain at the back. However, it has poor adhesion on glass proven by large peeling off of the glass fragments after gas gun experiments. Comparing with polyvinyl-butyral, thermoplastic-polyurethane has good adhesive properties with Sentry-glass-plus and glass. A multi-layered interlayer system using structural Sentry-glass-plus and adhesive thermoplastic-polyurethane as interlayers can significantly reduce the strain during impact and prevent glass fragments from flying off at high velocity which is favourable in real scenarios (e.g. bird-strike).
16
Deyu, Getnet Kacha. „Defect Modulation Doping for Transparent Conducting Oxide Materials“. Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAI071.
Der volle Inhalt der QuelleAnnotation:
Le dopage des matériaux semi-conducteurs est une partie fondamentale de la technologie moderne. Les oxydes conducteurs transparents (TCO) constituent une famille de semi-conducteurs, qui sont optiquement transparents et électriquement conducteurs. La conductivité électrique élevée est généralement obtenue grâce à un dopage associant des impuretés de substitution hétérovalentes comme dans In2O3 dopé au Sn (ITO), SnO2 dopé au fluor (FTO) et ZnO dopé à l'Al (AZO). Cependant, ces approches classiques ont dans de nombreux cas atteint leurs limites tant en ce qui concerne la densité de porteurs de charge atteignable, que pour la valeur de la mobilité des porteurs de charge. Le dopage par modulation est un mécanisme qui exploite l'alignement de la bande d'énergie à une interface entre deux matériaux pour induire une densité de porteurs de charges libres dans l’un d’entre eux ; un tel mécanisme a permis de montrer dans certains cas que la limitation liée à la mobilité pouvait ainsi était évitée. Cependant, la limite de densité de porteuse ne peut pas être levée par cette approche, du fait de l'alignement des limites de dopage par défauts intrinsèques. Le but de ce travail était de mettre en œuvre cette nouvelle stratégie de dopage pour les TCO. La stratégie repose sur l’utilisation de large bande interdite pour doper la surface des couches de TCO, ce qui résulte à un piégeage du niveau de Fermi pour la phase dopante et à un positionnement du niveau de Fermi en dehors de la limite de dopage dans les TCO. La méthode est testée en utilisant un TCO comme In2O3 non dopé, In2O3 dopé au Sn et SnO2 phase hôte et Al2O3 et SiO2-x en tant que phase de dopant gap à large bandeThe doping of semiconductor materials is a fundamental part of modern technology.Transparent conducting oxides (TCOs) are a group of semiconductors, which holds the features of being transparent and electrically conductive. The high electrical conductivity is usually obtained by typical doping with heterovalent substitutional impurities like in Sn-doped In2O3 (ITO), fluorine-doped SnO2 (FTO) and Al-doped ZnO (AZO). However, these classical approaches have in many cases reached their limits both in regard to achievable charge carrier density, as well as mobility. Modulation doping, a mechanism that exploits the energy band alignment at an interface between two materials to induce free charge carriers in one of them, has been shown to avoid the mobility limitation. However, the carrier density limit cannot be lifted by this approach, as the alignment of doping limits by intrinsic defects. The goal of this work was to implement the novel doping strategy for TCO materials. The strategy relies on using of defective wide band gap materials to dope the surface of the TCO layers, which results Fermi level pinning at the dopant phase and Fermi level positions outside the doping limit in the TCOs. The approach is tested by using undoped In2O3, Sn-doped In2O3 and SnO2 as TCO host phase and Al2O3 and SiO2−x as wide band gap dopant phase
17
Shanmugam, Naveenkumar. „Machining of transparent brittle material by laser-induced seed cracks“. Thesis, Kansas State University, 2015. http://hdl.handle.net/2097/20539.
Der volle Inhalt der QuelleAnnotation:
Master of ScienceIndustrial & Manufacturing Systems Engineering
Shuting Lei
Transparent brittle materials such as glass and silicon dioxide have begun to replace the conventional materials due to the advantageous properties including high strength and hardness, resistance to corrosion, wear, chemicals and heat, high electrical isolation, low optical absorption, large optical transmission range and biocompatibility. However because these materials are extremely hard and brittle, development of an ideal machining process has been a challenge for researchers. Non-traditional machining processes such as abrasive jet and ultrasonic machining have improved machining quality but these processes typically results with issues of poor surface integrity, high tool wear and low productivity. Therefore a machining technique that overcomes the disadvantages of existing methods must be developed. This study focused primarily on improving the machinability and attaining crack-free machined surfaces on transparent brittle materials by inducing micro cracks or seed damages on the subsurface of the materials. The hypothesis was that micro-cracks induced by femtosecond laser would synergistically assist the material removal process by a cutting tool by weakening or softening the material, followed by conventional machining process. Laser induced damages due to varying laser intensities and at different depths in bulk BK7 glass was studied in order to select the optimal laser machining conditions for the experiments. Dimensional and structural profiles of laser cracks are observed using an optical microscope. A comparative study of machined untreated BK7 samples and damage induced BK7 samples was conducted. Due to its simple process kinematics and tool geometry, orthogonal machining is used for the study. Results showed that machining laser-treated samples caused an average 75% force reduction on comparison to machining of untreated samples. Laser treated machined samples were produced without subsurface damages, and reduced tool wear was noted. Overall improved machinability of BK7 glass samples was achieved.
18
O'Neil, David H. „Materials chemistry and physics of the transparent conducting oxides“. Thesis, University of Oxford, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.670028.
Der volle Inhalt der Quelle
19
Hasbach, Ximena. „Natural carbonaceous materials for use in transparent Joule heaters“. Thesis, Massachusetts Institute of Technology, 2019. https://hdl.handle.net/1721.1/122181.
Der volle Inhalt der QuelleAnnotation:
Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2019Cataloged from PDF version of thesis.
Includes bibliographical references (page 35).
Natural carbonaceous materials have the potential to be used in a new class of more economically and environmentally sound electronic devices due to their tunable conductivity as well as robust mechanical and thermal properties. This study aims to explore the potential of steam cracker tar (SCT), a byproduct of ethylene production, for use in conductive applications, specifically transparent Joule heaters. The SCT was made into thin films using both rod-rolling and spray-coating methods. After the superior uniformity of the rod-rolled films was observed, a 2 laser cutter was used to anneal the rod-rolled films with the intention of increasing their sp² content and thus improving their conductivity. First the power and then the z-defocusing of the laser were varied, and the ability of the resulting films to heat was tested with an applied voltage. To test the conductivity and heating capabilities of the annealed SCT films, 60 volts were applied, the current measured, and the number of degrees heated measured with a thermal camera software. A combination of Raman spectroscopy and profilometry was used to characterize the films. The film with the best heating capabilities was found to be the one annealed with 8% laser power and 0.2 inch z-defocus. This film was observed to heat to 35 degrees Celsius, and was demonstrated to efficiently de-ice a frozen sheet of tempered glass. Future work in this study will focus on finding ways to improve conductivity in SCT films with better transparency.
by Ximena Hasbach.
S.B.
S.B. Massachusetts Institute of Technology, Department of Materials Science and Engineering
20
Shimotsuma, Yasuhiko. „Nano-modification of transparent materials using ultrafast pulse laser“. 京都大学 (Kyoto University), 2005. http://hdl.handle.net/2433/144535.
Der volle Inhalt der Quelle
21
Shimizu, Taiyo. „Studies on Transparent, Highly Porous Materials Based on Organopolysiloxanes“. 京都大学 (Kyoto University), 2017. http://hdl.handle.net/2433/225423.
Der volle Inhalt der Quelle
22
He, Tianda. „Electrospun Nanofibers and Their Applications in Transparent Electrodes“. University of Akron / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=akron1396876037.
Der volle Inhalt der Quelle
23
Horák, Karel. „Aplikace metod rozpoznávání obrazu v defektoskopii“. Doctoral thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2008. http://www.nusl.cz/ntk/nusl-233438.
Der volle Inhalt der QuelleAnnotation:
A lot of production lines contain camera inspection systems that increase quality of production. Therefore this presented work deals with applications of computer image processing methods in defectoscopy. Concretely the thesis is concerned with defects evaluation of glass bottles in food operations by the help of visual system BTCAM612, which is in existing configuration installed inland and in several foreign countries. The system is developed in conjunction with developer company CAMEA Ltd. from Brno and it is its sole ownership. The whole process of bottles inspection is described in sequence. First of all it is the hardware acquisition of images of three main controlled parts of bottles – neck, bottom and side. Next chapters are concentrated on image processing and features classification. The features are obtained from image by methods based on detection of in-homogeneities on glass material. Essential part of work is focused on filtration of synthetic patterns from bottles bottoms using function of complex invariants. These patterns are occurred especially in many plants in eastern countries, where marketplace with inspection systems and generally with quality inspection of industrial lines is expanded lately.
24
Norindr, Florian. „Study of inorganic transparent materials with near-infrared absorbing properties“. Thesis, University of Southampton, 2009. https://eprints.soton.ac.uk/171095/.
Der volle Inhalt der QuelleAnnotation:
The pigments investigated in this thesis were synthesised and characterised in order to find promising candidates for near-infrared absorbers. The chemical systems were chosen due to their absorbing properties and also their chemical and thermal stability and non-toxicity as well as for economical reasons. Investigations were undertaken on several phosphates and silicates.Within the group of phosphates, first several known copper compounds, i.e.Cu2P2O7, Cu4P2O9, Cu5P2O10, Cu3(PO4)2, Cu(PO3)2 and Cu2P4O12, were tested and the most suitable were chosen for more detailed experiments. The structure types with the general formula M2P2O7 were found to be promising and the metals calcium, strontium and copper were investigated as a starting point. It was confirmed that M2P2O7 (with M = Ca or Sr) and Cu2P2O7 could only form a pigment material for the middle member e.g. MCuP2O7. Better candidates were found in the systems Mg/Cu and Zn/Cu. Here solid solutions occur and the absorption behaviour could be adjusted according to the ratio of the metal cations. A series of different cation ratio compounds were synthesised for both systems. As Zn/Cu shows more favourable absorption properties compared to Mg/Cu, a full investigation of structural parameters including neutron powder diffraction and EXAFS studies was undertaken and the influence of the shape of M–O coordination spheres on the near-infrared absorption properties is discussed in detail. After deriving the successful concept it was investigated in two further chemical systems. First, the cation Fe2+ was used into the Zn3(PO4)2 structure to form a solid solution (Zn,Fe)3(PO4)2 and then Cu2+ was introduced into the Mg2Si2O6 pyroxene structure. Resulting from the studies, three promising systems for transparent near-infrared absorbing pigment applications were isolated: (Zn,Cu)2P2O7, (Zn,Fe)3(PO4)2 and (Mg,Cu)2Si2O6 solid solutions
25
Bréhault, Antoine. „Optiques moulées multi-spectrales transparentes dans le visible et l'infrarouge“. Thesis, Rennes 1, 2015. http://www.theses.fr/2015REN1S099/document.
Der volle Inhalt der QuelleAnnotation:
L’objectif principal de ce travail est de développer des optiques moulées transparentes du visible à l’infrarouge thermique 8-12μm pour des applications de vision multi-spectrales. La recherche de compositions de verres utilisables pour ces applications a été faite parmi les verres de chalcogénures (connus pour leurs grandes transparences dans l’infrarouge), plus précisément dans les systèmes GeS2-Ga2S3-CsCl et GeSe2-Ga2Se3-CsI. Ces deux systèmes présentent des transparences étendues dans le visible avec l’ajout d’halogénures d’alcalin.En privilégiant une transparence dans le domaine visible, le système à base de soufre a été plus précisément étudié avec la sélection de deux compositions 75GeS2-15Ga2S3-10CsCl et 65GeS2-20Ga2S3-15CsCl. Les transmissions optiques, les indices de réfraction, les dispersions chromatiques et les variations d’indices en fonction de la température pour ces compositions ont été mesurés. Les propriétés thermiques, la mise en forme des verres ainsi que les propriétés mécaniques ont été présentées pour compléter la caractérisation de ces matériaux. Ces compositions possèdent de bonnes stabilités contre la cristallisation et des transparences étendues de 0,5μm à 11,5μm. Ces résultats nous permettent d’envisager la production d’optiques couvrant une large bande spectrale et de proposer une alternative au matériau ZnS pour les systèmes optiques. Cependant, les dispersions chromatiques de ces deux verres possèdent des comportements très similaires. Une étude de ce paramètre important pour corriger les aberrations chromatiques a été faite pour permettre de déterminer une composition avec une dispersion différente.Pour ces verres, l’addition de chlorure de césium engendre une légère dégradation des propriétés optiques due à la réaction du verre avec l’humidité environnante. Pour protéger ces verres contre la corrosion de l’atmosphère, une couche protectrice de ZnS a été appliquée par pulvérisation cathodique. De plus, un traitement antireflet a été appliqué par Thales Angénieux pour optimiser la transmission de ces verres dans les bandes spectrales spécifiées. Ce revêtement antireflet agit également comme un revêtement de protection. Ces travaux sur des verres à base de GeS2-Ga2S3 pour des applications optiques, nous ont également conduits à étudier ces verres contenant des ions de sodium pour la conduction ionique avec l’ajout d’halogénure de sodium (NaI et NaCl). La conductivité ionique de ces verres a été mesurée et comparée à la conductivité des verres contenant du lithium. Il a été démontré que le système GeS2-Ga2S3-NaI peut conduire à des verres avec une conductivité ionique de 10-6 S.cm-1 à température ambianteThe objective of our study is to develop moldable optics operating simultaneously from the visible up to the thermal infrared region (8-12μm) for multispectral applications. The research of a suitable composition for optical applications has been done among chalcogenide glasses (well known for their extended transmission in the infrared domain), more precisely in the GeS2-Ga2S3-CsCl and GeSe2-Ga2Se3-CsI glass-forming systems. These two systems present extended transparency in the visible region due to alkali halide addition.In order to have enough transparency in the visible region, the sulfide based system has been more precisely studied with the selection of two compositions: 75GeS2-15Ga2S3-10CsCl and 65GeS2-20Ga2S3-15CsCl. Their optical transmissions, the refractive indices, the chromatic dispersions and the indices as function of temperature are studied. The thermal properties, molding ability and mechanical properties have been also studied in addition to the above-mentioned optical properties. These two compositions shows good stability against crystallization and extended transparency from 0,5 to 11,5 μm. It makes possible to consider the production of optics which cover a large spectral band, leading to an alternative to the ZnS for multispectral optical system. However, the chromatic dispersion of these two glasses is similar. A study of this important parameter as function of the glass composition has been performed in order to find a new composition with significantly different chromatic dispersion.For all these glasses, the addition of cesium chloride causes a slight degradation of optical properties due to its sensitivity to moisture. In order to protect these glasses against the atmospheric aggression, an efficient protective coatings of zinc sulfide has been applied by sputtering. An antireflective coating has been developed by Thales Angénieux to enhance the transmission in different specific wavelength ranges. The Antireflection coating acts also as a protective coating.This work on glasses in the GeS2- Ga2S3 system for optical applications, has also led us to study these glasses containing sodium ions for ionic conduction. The ionic conductivity has been measured and compared to that of glasses containing lithium ion. It has been demonstrated that the GeS2-Ga2S3-NaI can lead to glasses with an ionic conductivity of 10-6 S.cm-1 at room temperature
26
Hjerrild, Natasha E. „Silver nanowire transparent conductors for quantum dot photovoltaics“. Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:f1e7821e-1fcc-489b-86d2-13a3298205dd.
Der volle Inhalt der QuelleAnnotation:
This thesis studies the application of silver nanowire transparent conductors in PbS quantum dot photovoltaics. Silver nanowires were synthesized using a colloidal method and characterized using scanning electron microscopy. Nanowires were deposited on glass substrates by a stamp transfer process to generate a low density continuous network of conductive nanowires. This resulted in a highly conductive and transparent film appropriate for optoelectronic applications. Nanowire synthesis, deposition, and processing were optimised to produce transparent conductors suitable for thin film photovoltaics. These nanowire films were used to fabricate lead sulphide (PbS) colloidal quantum dot solar cells. In this structure, p-type PbS quantum dots form a junction with a n-type ZnO nanoparticle layer. A variety of fabrication and processing treatments were developed in order to reduce short-circuiting of devices and to enhance cell performance. Moderate nanowire density, improved ZnO adherence, slight device aging, and increased PbS film thickness proved to result in the highest quality devices. The champion device developed in this thesis achieved a power conversion efficiency of 2.2%.
27
Pascual, Pellicer Jordi. „irectrices energéticas integrales en edificios de oficinas transparentes (TOBEE)“. Doctoral thesis, Universitat Politècnica de Catalunya, 2016. http://hdl.handle.net/10803/385120.
Der volle Inhalt der QuelleAnnotation:
The main objective of this Thesis is to determine the behaviour, the energetic and economic feasibility, and the comfort conditions in office buildings, specifically for solutions with high proportions of glazing on facades and for Mediterranean climate. Ultimately, it is to contribute to the reduction of energy consumption of buildings for tertiary use offices, providing clear guidelines for the different actors involved in the life cycle of buildings, especially the owners, designers and the competent authorities in drafting specific sector regulations.
Similarly to what happens in other latitudes, the office buildings is the second use in constructed area, and it is up an average energy intensity significantly above the residential sector. The sector is characterized by a business model of continuity between actors, which in recent years has begun to assess the environmental vector significantly in the new constructions. Yet all this clashes with a reality characterized by an out-dated building stock, and a profound lack of knowledge related to the energy, economy and comfort conditions which difficult to reverse the current situation. This is more relevant in a context in which, for various reasons, in recent decades has dominated the construction of glazing office buildings. This Thesis aims to overcome this ignorance with tools to assess, in a comparative way, some of the most common office building solutions, and determine the key elements that determine the energy bill of those constructions.
Thus, in regulation conditions and Mediterranean climate, office buildings with heavy structural solutions and more opaque facades result in lower consumption of primary energy and costs, both in investment and in life cycle, lower than for cases of lighter structures with larger proportion of glazing in facades, which derives extra difficulties to achieves de desired comfort conditions. Although notes the existence of some transparent designs (operated double skin) getting equivalent energy demands to those of opaque solutions, this is at the expense of a higher investment and operational life costs. These guidelines are valid even for improved scenarios in which, despite reducing the energy demand, the results become proportional to the different construction solutions. Thus, considering that the different limits designed for the scenario¿s analysis of the Thesis tend to narrow these guidelines, it's concluded that the transparent office buildings are inefficient, both energy and economically.
Although the aim of the thesis is demonstrative for the different actors, and therefore the display formats of results are considered for easily understanding, the procedure developed highlights the relevance of the field data and the potential of using coupled simulation tools. The current behaviour of this type of construction sheds consumption clearly superior to those associated with their regulations conditions of use, so the sensitivity analysis of these factors are believed important in the design of buildings for this purpose (more on solutions deeply susceptible to the environment, such as the glazed facades). For its part, the coupled use of dynamic simulation tools allows the observation of phenomena that affect comfort, thermal but especially luminous.
Although the results obtained are specific guidelines for office buildings in a Mediterranean environment, the same trends have been observed elsewhere (as in Madrid, through a broader PhD own subsequent study, http://Aiguasol.coop/2014/02/17/project-tobeem/).
Improve the performance of office buildings depends on the different actors involved in its life cycle. In the first instance, of the competent authority, but also of the owners and promoters, of the designers and of the end users. All this is more feasible in more opaque buildings with higher inertia.El objetivo principal de la presente Tesis es determinar el comportamiento y la viabilidad energética, económica y de confort en edificios de oficinas, específicamente para soluciones con elevadas proporciones de hueco en piel y en clima Mediterráneo. Se pretende, en última instancia, contribuir a la reducción del consumo energético de los edificios de uso terciario oficinas, ofreciendo directrices claras para los distintos actores que participan en el ciclo de vida de los edificios, en especial los propietarios, los proyectistas y las autoridades competentes en la redacción de normativas específicas del sector. El sector de los edificios de oficinas representa el segundo uso en superficie construida, y le corresponde una intensidad energética promedio significativamente superior al sector residencial. El sector se caracteriza por un modelo de negocio de continuidad entre actores. Sin embargo todo lo anterior choca con una realidad caracterizada por un parque edificatorio obsoleto, y un desconocimiento profundo del comportamiento energético, económico y de condiciones de confort. Esto es más relevante en un contexto en que en los últimos lustros ha predominado la construcción de edificios de oficinas de elevadas proporciones de hueco en fachada. Esta Tesis pretende paliar este desconocimiento con herramientas que permiten valorar algunas de las soluciones constructivas más comunes del sector, y determinar los elementos clave que condicionan la factura energética de los edificios. Así, en condiciones consideradas de carácter normativo y en clima Mediterráneo, los edificios de oficinas con soluciones estructuralmente pesadas y fachadas más opacas resultan en consumos de energía primaria más reducidos y costes, tanto en inversión como en vida útil, inferiores respecto a casos de estructuras más ligeras y mayor proporción de huecos en fachadas, bajo unas condiciones de confort más difíciles de alcanzar en estos últimos. Aunque se constata la existencia de algunos diseños transparentes (doble piel operada) que consiguen unas demandas energéticas equivalentes a las de las soluciones opacas, esto es a costa de unas inversiones y costes de vida útil mayores. Estas directrices se mantienen aún cuando se plantean escenarios de mejora que, a pesar de reducir la demanda energética, lo hacen de forma proporcional a las distintas soluciones constructivas. De esta forma, y considerando que los distintos límites impuestos en el análisis de escenarios de la Tesis tienden a acotar estas directrices observadas, se concluye que los edificios de oficinas transparentes son ineficientes, tanto energética como económicamente. Aunque la finalidad de la Tesis es demostrativa para los distintos actores, y por ello se muestran formatos de visualización de resultados de fácil comprensión, en el procedimiento desarrollado destaca la relevancia de los datos de campo y el potencial del uso de herramientas de simulación acopladas. El comportamiento real de este tipo de construcciones arroja consumos claramente superiores a los asociados a sus condiciones de uso normativas, por lo que se cree relevante el análisis de sensibilidad de estos condicionantes en el diseño de edificios de este uso (más en las soluciones más susceptibles al entorno, como las de elevada proporción de huecos). Por su parte, el uso acoplado de herramientas de simulación dinámica permite la constatación de fenómenos que afectan al confort, térmico pero sobre todo lumínico, de estas soluciones. Aunque los resultados y las directrices obtenidas son específicas para edificios de oficinas en un entorno Mediterráneo, se han observado las mismas tendencias en otras latitudes (como en Madrid, a través de un estudio posterior más amplio del propio Doctorando, http://aiguasol.coop/2014/02/17/proyecto-tobeem/). Mejorar el comportamiento de los edificios de oficinas depende de los distintos actores involucrados en su ciclo de vida. Ello resulta más viable en edificios con menor proporción de hueco.
28
Hoffmann, Wolf-Martin. „Laserdurchstrahlschweissen unpigmentierter Kunststoffe /“. Aachen : Mainz, 2008. http://d-nb.info/99412841X/04.
Der volle Inhalt der Quelle
29
Wang, Shu Jun. „Applications of graphene for transparent conductors and polymer nanocomposites /“. View abstract or full-text, 2009. http://library.ust.hk/cgi/db/thesis.pl?MECH%202009%20WANGS.
Der volle Inhalt der Quelle
30
Ghosh, Dhriti Sundar. „Ultrathin metal transparent electrodes for the optoelectronics industry“. Doctoral thesis, Universitat Politècnica de Catalunya, 2012. http://hdl.handle.net/10803/285839.
Der volle Inhalt der QuelleAnnotation:
Transparent electrodes (TEs) are the essential elements of many optoelectronic devices such as solar cells, touch screens, organic LEDs, and LCDs. Consequently demand for TEs is growing very steeply and the market value presently stands at 8 billion USDs. The state-of-art indium tin oxide (ITO) has an excellent trade-off between optical transparency and electrical sheet resistance but suffers from several drawbacks, mainly the increasing cost due to indium shortage, and inadequate flexibility due to poor mechanical ductility.
This thesis presents the development of a new class of TEs based on ultrathin metal films (UTMFs). The work started from understanding the fundamental aspects of UTMF growth and properties, and then focused on different UTMF based geometries, composition, and combination for potential applications in different optoelectronic applications.
Single component ultrathin Ni and Cr films were shown to possess significantly high transparency in the ultraviolet (175–400 nm) and mid-infrared
(2.5–25 μm) regions making them viable TE for devices such as UV photodiodes, and IR pyroelectric detectors. The natural oxidation process, which is a major concern for metal films, has been exploited to achieve stable metallic films by inducing a protective oxide layer.
In another proposed novel design, incorporating an ad hoc conductive grid, the sheet resistance of UTMFs can be reduced by more than two orders of magnitude with negligible loss in transparency, which in turn eliminates the inverse trade-off relationship between optical transparency and electrical conductivity of continuous metal based TEs.
A TE structure based on the ultrathin conductive Cu films with an application specific functionalized capping layer of Ti or Ni layer has been demonstrated. The properties of the TE can be tuned accordingly and show excellent stability against temperature, and oxidation. The suitability of Ag-Cu alloy films as TE as an alternative to ITO has been also investigated. The optical spectrum of such alloy films follows the average optical behavior of single component Cu and Ag layers, thus resulting in a much flatter optical response in the visible region.
UTMFs combined with Al doped ZnO (AZO), which is possible ITO replacement, has also been demonstrated to show the possibility of hybridizing the two technologies. A bilayer Ag/AZO has been developed which can overcome the high reflection of metals and retain their good electrical behavior, while maintaining a minimum total film thickness. In another structure, UTMF capping layer were used to improve the stability of AZO. It was found that an ultrathin oxidized Ni capping layer with a thickness at percolation threshold greatly enhances the stability of AZO layer in harsh environment without affecting the electro-optical propertiesLos electrodos transparentes (TEs) son elementos básicos de muchos dispositivos optoelectrónicos, tales como células solares, pantallas táctiles, LEDs orgánicos i LCDs. En consecuencia, la demanda de éstos TEs está creciendo paulatinamente y con un valor de mercado actual de 8 billones de dólares (USD). El estado del arte del óxido de estaño dopado con Indio (ITO) ofrece un excelente compromiso entre transparencia óptica y resistencia eléctrica de hoja pero también tiene inconvenientes, principalmente de precio debido a la escasez del Indio, así como de una inadecuada flexibilidad debida a una baja ductilidad mecánica. En esta tesis se presenta el desarrollo de una nueva clase de TEs basados en capas ultradelgadas de metales (UTMFs). El trabajo empieza des de la comprensión de los aspectos fundamentales relacionados con el crecimiento de los UTMF y sus propiedades, para luego focalizarse en diferentes geometrías, composición y combinaciones para diferentes aplicaciones potenciales en el campo de la optoelectrónica. Las capas ultradelgadas monocomponentes de Ni y de Cr han mostrado tener significativamente alta transparencia en el rango ultravioleta (175-380nm) y en el Infrarrojo mediano (2.5-25um), haciéndolos, por tanto, TE viables para dispositivos tales como fotodiodos de UV y detectores piroeléctricos del IR. El proceso natural de oxidación, el cual es un problema central para las capas metálicas, ha sido aprovechado para conseguir capas metálicas estables gracias a una capa protectora de óxido. En otro novedoso diseño, gracias a la incorporación ad hoc de una malla conductora, la resistencia eléctrica de hoja de los UTMFs puede ser disminuida hasta dos órdenes de magnitud y con una pérdida de transmisión despreciable, y por lo tanto, elimina el compromiso limitante entre transparencia óptica y conductividad eléctrica de los TE basados en capas metálicas continuas. Una estructura de los TEs, basada en una capa conductora ultradelgada de Cu, la cual puede ser funcionalizada para aplicaciones específicas con capas protectoras de Ti o Ni, ha sido demostrada. Las propiedades del TE pueden ser modificadas bajo control y muestran una excelente estabilidad a la temperatura y la oxidación. La idoneidad de la aleación Ag-Cu como capa alternativa al ITO para los TE ha sido también investigada. El espectro óptico de esta aleación sigue el comportamiento óptico medio de las capas monocomponentes de Ag y Cu, y por lo tanto se obtiene una respuesta óptica mucho mas plana en la región del espectro visible. Los UTMFs en combinación con ZnO dopado con Al (AZO), el cual es una opción factible como sustituto del ITO, ha demostrado la posibilidad de hibridar ambas tecnologías. Una bicapa de Ag/AZO ha sido desarrollada, la cual evita el problema de la alta reflexión de los metales y mantiene a su vez sus buenas propiedades eléctricas con un espesor total de capa mínimo. En otra estructura, la capa protectora de los UTMF ha sido utilizada para mejorar la estabilidad del AZO. Se ha visto que una capa protectora ultra-delgada y oxidada de Ni con un espesor igual a su límite de percolación, mejora notablemente la estabilidad de las capas de AZO, manteniendo sus propiedades electro-ópticas, incluso en condiciones severas
31
Mauclair, Cyril. „Spatio-temporal ultrafast laser tailoring for bulk functionalization of transparent materials“. Phd thesis, Université Jean Monnet - Saint-Etienne, 2010. http://tel.archives-ouvertes.fr/tel-00488647.
Der volle Inhalt der QuelleAnnotation:
In the past decade, ultrashort laser sources have had a decisive impact on material processing for photonic applications. The technique is usually restricted to the elemental association of an ultrashort source with a focusing lens. It is thus limited in the achievable bulk modifications. Accompanying studies of material modifications in space and time, we propose here that automated spatio-temporal tailoring of the laser pulses is an efficient manner to overcome these limitations. More precisely, we demonstrate the generation of multiple processing foci for synchronous photomachining of multiple devices in the bulk. Thus, we report on the parallel photowriting of waveguides, light couplers, light dividers in 2D/3D in fused silica glass. We show that the domain of photowriting can be extended to deep focusing. We indicate that this can be achieved by wavefront shaping or temporal profile tailoring conducted by an evolutionary optimization loop. We also have unveiled a singular interaction regime where regular structuring takes place before the focal region. For the first time, the dynamics of the energy coupling to the glassy matrix is evaluated for various temporal pulse profiles. Enhanced energy confinement in the case of picosecond pulses is confirmed by characterization of the transient electronic gas and of the subsequent pressure. These pump-probe studies were carried out with a self-build time-resolved microscopy system with temporally shaped pump irradiation. We also developed a new method based on the Drude model to differentiate the electronic and matrix contributions to the contrast of the microscopy images.
32
Caballero, Lucas Francesc. „Z-scan methods for ultrashort pulsed laser microprocessing of transparent materials“. Doctoral thesis, Universitat de Barcelona, 2019. http://hdl.handle.net/10803/668185.
Der volle Inhalt der QuelleAnnotation:
The use of femtosecond lasers has recently gained attention as a result of the recognition to Gérard Mourou and Donna Strickland with the award of the Nobel Prize in Physics 2018 "for their method of generating high-intensity, ultra-short optical pulses". The innumerable areas of application of ultrashort laser pulses have not yet been completely explored, but their possibilities for accessing the microworld are considered highly valuable.
Following this spirit, the objective of this thesis consisted in proposing and implementing feasible solutions to the challenges involved in the microfabrication of materials with ultrashort laser pulses for diverse advanced applications. To that end, attention was put in laser ablation of transparent polymers with spatial resolutions that transcend sharpness limitations due to light diffraction.
The results presented here were obtained during the development of the doctorate studies of the PhD program in Nanosciences at the Departament de Física Aplicada of the Universitat de Barcelona. It is structured as follows:
INTRODUCTION AND OBJECTIVES: This introductory chapter contains a description of the most significant microfabrication techniques, centered on laser-based methods. Having a key role in this thesis, the interaction between laser radiation and matter is shortly reviewed. The physical phenomena motivate the use of femtosecond lasers for the precise processing of transparent materials, where focus is put on their superficial laser ablation, the entailing challenges and its applications. The objectives pursued in this work close this first chapter.
EXPERIMENTAL: A description of the experimental setups implementing femtosecond laser systems, methods and materials applied during the trials constituting the developed research is presented in this chapter. The features of the laser sources together with the corresponding laser direct-write setups form the sections of this chapter, followed by some comments on Gaussian beams and their focusing. These found the presentation of the z-scan focusing technique. To close this chapter, some remarks and background about the employed materials are delivered.
Z-SCAN FOCUSING METHOD: The results obtained by putting to work the z-scan focusing technique introduced in the previous chapter are presented here. The theme is the development and characterization of the z-scan focusing technique as a method to address the issue of securing surface ablation of transparent material with femtosecond laser pulses. Its successful implementation in surface ablation of the transparent polymer polymethyl methacrylate (PMMA) with high spatial resolution is given as proof of the viability of the proposed strategy for a precise focusing of laser beams onto transparent materials.
The contents of this chapter include studies on transmittance and reflectance measurements at different focusing distances between the laser beam waist and the processed material surface through single laser pulse surface ablation and laser surface scanning for channel microfabrication (comparing their results), the beam waist position determination thanks to the transmittance measurements and analysis of the produced surface ablation.
APPLICATIONS IN LASER MICROFABRICATION OF MATERIALS: the implementation of the developed z- scan focusing technique was put to use in laser microfabrication of materials with diverse applications.
The applications include the irradiation with femtosecond laser pulses of biodegradable polymers for profound hole ablation in polylactic acid (PLA) and study of the its influence in biodegradability of polylactic-co-glycolic acid, the laser perforation for leakage studies on
medical use polypropylene bags, and the laser fabrication of microfluidic guides for conductive line printing.
Owing to their diversity the chapter is divided in four sections, one for each topic. The various processed materials are briefly introduced, with some background supporting their study.
CONCLUSIONS: The last chapter sums up the most relevant results and main achievements that have been obtained during the development of this thesis in the form of closing remarks.L’ús de làsers d’impulsos ultracurts ha rebut atenció recentment degut al reconeixement amb el Premi Nobel de Física de l’any 2018 a la tècnica que en permet la seva generació. Les seves àrees d’aplicació encara no han estat completament explorades, però les seves possibilitats per accedir al món microscòpic són considerades prometedores. Seguint aquest esperit, l’objectiu d’aquesta tesi és proposar i implementar solucions viables als reptes relacionats amb la microfabricació de materials amb impulsos làser ultracurts, específicament l’ablació làser de polímers transparents amb resolucions espacials que transcendeixin les limitacions de definició associades a la difracció de la llum. INTRODUCCIÓ I OBJECTIUS: Aquest capítol descriu les tècniques de microfabricació més significatives, centrant-se en els mètodes làser. Degut al paper clau del làser en aquesta tesi, es fa una descripció breu de la interacció entre la radiació làser i la matèria. Els objectius plantejats completen aquest primer capítol. EXPERIMENTAL: En aquest apartat es presenta una descripció dels muntatges experimentals amb sistemes làser de duració ultracurta, els mètodes i els materials emprats durant les proves que constitueixen la recerca i que serveixen de base per a la presentació del mètode d’enfocament z-scan. MÈTODE D’ENFOCAMENT Z-SCAN: Els resultats obtinguts amb la tècnica proposada d’enfocament per z-scan són presentats aquí. El tema central és el desenvolupament i caracterització d’aquesta tècnica com a mètode per l’ablació superficial de materials transparents amb impulsos làser ultracurts. La implementació exitosa de l’ablació superficial del polimetilmetacrilat (PMMA) amb elevada resolució espacial demostra la viabilitat de l’estratègia proposada per enfocar amb precisió un feix làser a la superfície de materials transparents. APLICACIONS PER AL MICROPROCESSAMENT LÀSER DE MATERIALS: La implementació de la tècnica desenvolupada d’enfocament per z-scan s’ha pogut traslladar al microprocessament de materials amb làser en diverses aplicacions com la irradiació de polímers biodegradables per a la producció de forats profunds en àcid polílàctic (PLA), la seva influència en la biodegradabilitat de l’àcid polílàctic-co-glicòlic (PLGA), la perforació de fuites en bosses de polipropilè d’ús mèdic, i la fabricació de guies microfluídiques per la impressió de línies conductores. Conclusions: L’últim capítol resumeix els resultats més rellevants i els principals assoliments.
33
Robinson-Gayle, Syreeta. „Environmental impact and performance of transparent building envelope materials and systems“. Thesis, Brunel University, 2003. http://bura.brunel.ac.uk/handle/2438/5445.
Der volle Inhalt der QuelleAnnotation:
Building envelopes are elements with a long lifetime, which provide a barrier between internal and external space and contribute to the internal environmental conditions provision. Their complex role ensures a large impact on the environmental and energy performance of a building and the occupant perception of a space. This study looks at the use of novel materials and processes to help reduce the environmental impact of buildings by improving facade and transparent roof design. There are three main strands to the work. First, novel building components, ETFE foil cushions were examined. Physical testing has shown that ETFE foil cushions compare favourably to double glazing in terms of thermal and daylighting performance which was also noted as one of the most likeable feature by occupants. Environmental impact analysis has indicated that ETFE foils can reduce the environmental impact of a building through reduced environmental burden of both the construction and operation of the building. Secondly, a cradle-to-gate Life Cycle Analysis (LCA) was carried out for float glass, which considered the environmental impacts of glass manufacture. The embodied energy was calculated to be 13.4 ± 0.5 GJ per tonne while the total number of eco-points 243 ± 11 per tonne. It is shown that float glass is comparable to the use of steel, and highly preferable to the use of aluminium as a cladding panel. Finally, a concept design tool (FACADE) was developed by defining a large number of office facade models and employing dynamic thermal, daylighting and environmental impact modelling to create a database which can be accessed through a user friendly interface application. A parametric analysis has indicated that using natural ventilation where possible can reduce the environmental impact of offices by up to 16%. Improving the standard of the facade and reducing the internal heat loads from lighting and equipment can reduce environmental impact up to 22%. This study makes a significant contribution to understanding the environmental impact of building envelope individual and integrated components.
34
Zhu, Zhaozhao, und Zhaozhao Zhu. „Emerging Materials for Transparent Conductive Electrodes and Their Applications in Photovoltaics“. Diss., The University of Arizona, 2017. http://hdl.handle.net/10150/623062.
Der volle Inhalt der QuelleAnnotation:
Clean and affordable energy, especially solar energy, is becoming more and more important as our annual total energy consumption keeps rising. However, to make solar energy more affordable and accessible, the cost for fabrication, transportation and assembly of all components need to be reduced. As a crucial component for solar cells, transparent conductive electrode (TCE) can determine the cost and performance. A light weight, easy-to-fabricate and cost-effective new generation TCE is thus needed. While indium-doped tin oxide (ITO) has been the most widely used material for commercial applications as TCEs, its cost has gone up due to the limited global supply of indium. This is not only due to the scarcity of the element itself, but also the massive production of various opto-electronic devices such as TVs, smartphones and tablets. In order to reduce the cost for fabricating large area solar cells, substitute materials for ITO should be developed. These materials should have similar optical transmittance in the visible wavelength range, as well as similar electrical conductivity (sheet resistance) to ITO. This work starts with synthesizing ITO-replacing nano-materials, such as copper nanowires (CuNWs), derivative zinc oxide (ZnO) thin films, reduced graphene oxide (rGO) and so on. Further, we applied various deposition techniques, including spin-coating, spray-coating, Mayer-rod coating, filtration and transferring, to coat transparent substrates with these materials in order to fabricate TCEs. We characterize these materials and analyze their electrical/optical properties as TCEs. Additionally, these fabricated single-material-based TCEs were tested in various lab conditions, and their shortcomings (instability, rigidity, etc.) were highlighted. In order to address these issues, we hybridized the different materials to combine their strengths and compared the properties to single-material based TCEs. The multiple hybridized TCEs have comparable optical/electrical metrics to ITO. The doped-ZnO TCEs exhibit high optical transmittance over 90% in the visible range and low sheet resistance under 200Ω/sq. For CuNW-based composite electrodes, ~ 85% optical transmittance and ~ 25Ω/sq were observed. Meanwhile, the hybridization of materials adds additional features such as flexibility or resistance to corrosion. Finally, as a proof of concept, the CuNW-based composite TCEs were tested in dye-sensitized solar cells (DSSCs), showing similar performance to ITO based samples.
35
Hua, Bin. „Studies on microstructure modification in transparent materials by femtosecond laser pulses“. 京都大学 (Kyoto University), 2006. http://hdl.handle.net/2433/136159.
Der volle Inhalt der Quelle
36
Sun, Yanyi. „Glazing system with transparent insulation material for building energy saving and daylight comfort“. Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/39864/.
Der volle Inhalt der QuelleAnnotation:
Concerns over sustainability in the built environment have resulted in continuous efforts to improve the performance of window system or glazed façade and hence indoor comfort and building energy conservation. An innovative façade system where parallel transparent/translucent plastic slats are sandwiched between glass panes to form a Parallel Slat Transparent Insulation Material (PS-TIM) is proposed as a strategy to effectively reduce heat transfer between the panes of a double glazed window, while maintaining access to daylight. A holistic investigation of the window system with PS- TIMs is conducted in terms of thermal and optical properties, as well as detailed daylight and energy performance predictions of applying PS-TIMs in buildings. Firstly, an experimental investigation is undertaken in a large climate chamber, and the measurement results were used to validate a two-dimensional Computational Fluid Dynamics (CFD) model. Secondly, the validated 2D CFD model is used to solve the dynamic thermal properties of different configurations of PS-TIMs under various environmental conditions. The optical properties (i.e. Bidirectional Scattering Distribution Function (BSDF)) of PS-TIMs are obtained via a ray-tracing technique based on the structures’ geometries and the material optical characteristics of the interstitial structure. The detailed annual daylight performance in different climates and building orientations are predicted using RADIANCE. Finally, the optical and thermal properties obtained from the previous fundamental models are applied in EnergyPlus to predict the energy performance (i.e. heating, cooling and lighting energy consumption) of applying PS-TIMs in buildings in different climates. The investigation results provide a better understanding of the benefits of PS-TIM in terms of energy saving and daylight comfort improvement, as well as offer some tentative suggestions as to how architects and engineers might apply PS-TIM to window system or glazed façade.
37
Mei, Jun S. B. Massachusetts Institute of Technology. „Photoluminescence quenching of organic thin films by transparent conductive oxides“. Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/35059.
Der volle Inhalt der QuelleAnnotation:
Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2006.Includes bibliographical references (p. 83-86).
One fundamental challenge in designing organic light-emitting diodes is luminescence quenching near an electrode. In this work, we investigate the underlying mechanism behind luminescence quenching by measuring the reduction in Alq3 photoluminescence due to SnO02. Using an analytical model and a Monte Carlo simulation for exciton dynamics in amorphous organic solids, we find that the exciton diffusion length in bulk Alq3 is in the range of 70--80 A. We also find that for SnO2 films deposited without oxygen in the sputtering ambient, resonant energy transfer from Alq3 to SnO2 is the dominant quenching mechanism. By varying the oxygen content in the Ar/C)2 sputtering gas mixture, we find that the energy transfer distance decreases from 10--25 A for 0% 02 to less than 2 A for 10% 02. Our experimental results suggest that because excess oxygen reduces oxygen vacancies and defect electronic states in SnO2, it leads to a smaller spectral overlap between the emission of Alq3 and the absorption of SnO2, thereby shortening the energy transfer distance and reducing the quenching capability of SnO2.
by Jun Mei.
S.B.
38
Lee, Min-Hsuan. „Solution-processable organic-inorganic hybrid transparent electrode for optoelectronic applications“. HKBU Institutional Repository, 2016. https://repository.hkbu.edu.hk/etd_oa/320.
Der volle Inhalt der QuelleAnnotation:
The aim of this PhD thesis is to undertake a comprehensive research to study the optical, electrical, surface electronic and morphologic properties, formulation and surface modification of solution processable organic-inorganic hybrid transparent electrodes as well as their applications in optoelectronic devices. In this study, MoO3 nanoparticles and graphene oxide (GO) nanosheets were incorporated into the poly(3,4-ethylenedioxythiophene) -poly(styrenesulfonate) (PEDOT:PSS) layer forming a hybrid anode interfacial layer (AIL) and subsequently a hybrid transparent electrode of AIL/silver nanowires (AgNWs), significantly improved charge injection in CdSe/ZnS-based quantum dot-light emitting diodes (QD-LEDs) and charge collection in bulk heterojunction (BHJ) organic solar cells (OSCs). The effect of oxidation behavior and charge transfer between PEDOT and MoO3, as well as PEDOT and GO, on the enhancement in conductivity of hybrid PEDOT:PSS-MoO3 and PEDOT:PSS-GO AILs was investigated systematically. The presence of a PEDOT:PSS-MoO3 AIL promotes a good interfacial contact between the hole transporting layer (HTL) and the solution-processed hybrid transparent electrode for efficient operation of QD-LEDs. This work reveals that the use of the hybrid PEDOT:PSS-MoO3 AIL benefits the performance of QD-LEDs in two ways: (1) to assist in efficient hole injection, thereby improving luminous efficiency of QD-LEDs, and (2) to improve electron-hole current balance and suppression of interfacial defects at the QD/electrode interface. The surface wettability of the PEDOT:PSS-MoO3 AIL was controlled successfully for making a good contact between the HTL and the AgNWs, enabling efficient charge injection or charge collection, and thereby improvement in the device performance. The effect of PEDOT:PSS-GO AIL on the performance of transparent QD-LEDs was also analyzed. The maximum brightness of the transparent QD-LEDs, made with a solution-processed hybrid top transparent electrode of PEDOT:PSS-GO/AgNWs, is 3633 cd/m2 at 15 V, comparable to that of a structurally identical control QD-LED made with an evaporated Ag electrode, with a brightness of 4218 cd/m2 operated under the same condition. The change in the hydrophobicity of the PEDOT:PSS-GO AIL, e.g., from the hydrophobic to hydrophilic characteristics, was observed. The interaction between PEDOT and GO nanosheets induces the transition between benzoid-quinoid structures, contributing to the enhanced charge carrier transport via the PEDOT:PSS-GO AIL. The energy level alignment at the HTL/electrode interface and the excellent electrical conductivity of PEDOT:PSS- GO/AgNWs transparent electrode result in an obvious improvement in the performance of QD-LEDs. Transparent QD-LEDs also demonstrated remarkable efficiency via cathode interfacial engineering. Two cathode interfacial modifications include incorporating (1) a hybrid bathophenanthroline (Bphen):Cs2CO3-based electron transporting buffer layer (EBL) and (2) a conjugate polymer of poly[(9,9-bis(3'-((N,N-dimethyl)-N-ethylammonium)-propyl)-2,7- fluorene)-alt-2,7-(9,9-dioctylfluorene)] (PFN-Br)-based EBL. The approach of n-doping effect in the BPhen:Cs2CO3 EBL not only modifies the surface electronic properties of the ZnO electron transporting layer (ETL) but also improves the electron injection at the QD/cathode interface. The n-doping mechanism in the Bphen:Cs2CO3 EBL was investigated. PFN-Br EBL has also been employed to tune the surface work function of ZnO ETL. It was observed that the ZnO/PFN-Br formed an interfacial dipole at the ETL/QD interface, which is suitable for efficient electron injection in the transparent QD-LEDs. In order to improve electron-hole current balance, a GO/MoO3-based multilayer AIL was adopted facilitating efficient charge transfer through improved energy level alignment at the HTL/hybrid electrode interface. Photoelectron spectroscopy revealed tuned surface work function with reduced interfacial barrier for efficient hole injection in transparent QD-LEDs. In these devices, the cathode and anode interfacial modifications have been optimized and studied. This study was also extended to investigate the effect of the organic-inorganic hybrid electrode on performance enhancement of all solution processable organic solar cells (OSCs). The reduction in series resistance and increase in shunt resistance of solution-processed OSCs originated from improved contact selectivity as well as enhanced charge collection efficiency. These properties are reflected in the significantly improved fill factor and short-circuit photocurrent density for the all solution-processed OSCs. Enhanced charge collection at the BHJ/electrode interfaces and improved process compatibility are mainly responsible for efficiency improvement in the cells. The outcomes of this work would allow further advances in device performance. This research also highlights the need to explore interfacial electronic properties and reduce energetic barrier at BHJ/electrode interfaces in fully solution-processed OSCs through photoelectron spectroscopy measurements. The results of this research demonstrate that the solution processable organic-inorganic hybrid transparent electrode developed in this work is beneficial for application in fully solution-processed optoelectronic devices.
39
Campion, Michael J. (Michael John). „Understanding the oxidation and reduction process in transparent conducting oxides“. Thesis, Massachusetts Institute of Technology, 2018. https://hdl.handle.net/1721.1/121604.
Der volle Inhalt der QuelleAnnotation:
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2019Cataloged from PDF version of thesis.
Includes bibliographical references (pages 133-141).
Transparent conductors play important roles in many optoelectronic devices such as LEDs, thin film solar cells, and smart windows through their ability to efficiently transport both photons and electrons. Simultaneous requirements of a wide band gap, high free carrier concentration, and high electron mobility limits the selection of available transparent conductor materials. Further improvements in the optical and electrical properties, along with improvements in processing tolerance, are highly desirable for this material class. One key limitation of current transparent conducting oxides is their response to oxidation, which can cause severe decreases to the conductivity of the material through ionic compensation. Materials with slow oxygen kinetics or resistance to the formation of compensating ionic defects could lead to more flexible operating and processing conditions for applications requiring transparent conductors.
The properties of transparent conducting oxides, Al-doped ZnO and La-doped BaSnO₃, were examined through a variety of methods with a focus on the impact of processing on the free carrier concentration, electron transport, and optical properties. Al-doped ZnO was examined as a well-known alternative to indium tin oxide (ITO) that has been shown to be limited by relatively narrow processing conditions and large variances in reported properties. BaSnO₃ is a comparatively new material in the field of transparent conductors, attractive mainly due to its exceptionally high electron mobility for an oxide. Little is currently known about the nature of defects and processing on the optical and electrical properties of this material, but this information will be important to understand before implementing this material in practical devices.
For these materials, I examined the roles of oxygen stoichiometry and point defect formation in impacting properties and stability under both processing conditions and harsh operating conditions and explored the limitations and opportunities provided by these transparent conducting oxide systems. Al-doped ZnO thin films were produced by pulsed laser deposition under a variety of oxygen conditions demonstrating the strong dependence of free electron concentration and mobility on the oxidation state of the material. The free carrier absorption in the infrared photon range was measured and modeled and found to agree well with theory assuming ionized impurity scattering as the limiting electron scattering mechanism. These effects were understood through the framework of the formation of compensating zinc vacancies under oxidizing conditions, leading to decreases in the free electron concentration.
Atom probe tomography was applied to Al-doped ZnO thin films deposited on Si substrates, demonstrating an effective accumulation of Al near the ZnO/Si interface, but with no detected precipitation or agglomeration in the x-y plane of the film, even for heavily doped films. This was surprising due to the high concentration of Al-dopant in the material, exceeding the thermodynamic solubility limit of bulk ZnO. An accumulation of Al-dopant was observed at the ZnO/Si interface under multiple conditions, with the oxygen atmosphere during deposition and nature of the Si substrate affecting the degree of accumulation. Because transparent conductors are typically used to transfer charge through interfaces, understanding the nature and implications of this observed accumulation effect could be essential to understanding device performance.
La-doped and undoped BaSnO₃ thin films and bulk samples were tested for their electrical conductivity in-situ under various temperatures and oxygen partial pressures. In the undoped case, a p-type to n-type transition was observed at lower temperatures with decreasing oxygen partial pressure, with the behavior correlated to the formation and annihilation of oxygen and cation vacancies. Under donor-doping, a measurable, but weak n-type dependence of conductivity was demonstrated, pointing to a surprisingly weak role played by cation vacancy charge compensation over the measured temperature ranges. Compared to other similar oxide systems, compensation by cation vacancies would normally be expected to be strong under oxidizing conditions.
This is a key advantage for La-doped BaSnO₃ as a high temperature oxygen stable material compared to other competing materials that are more susceptible to conductivity degradation due to ionic compensation of the donor dopant under oxidizing conditions. This was directly demonstrated in the testing of the conductivity response of La-doped BaSnO₃ thin films that maintained high conductivity under a large range of oxygen and temperature conditions. Oxygen diffusion in the material was estimated from conductivity relaxation and further explored with oxygen tracer diffusion studies. These studies revealed an activation energy of 2 eV for the oxygen diffusion process, as well as a depth dependent diffusivity leading to depressed oxygen diffusivities near the surface. Study of epitaxial and polycrystalline thin films of La-doped BaSnO₃ revealed a difference in the rate of oxidation response of the conductivity.
Epitaxial thin films exhibited a weak power law dependence on temperature while polycrystalline thin films under oxidizing conditions exhibited an activation energy of 0.36 eV. This effect was attributed to the formation of narrow space charge regions at the grain boundaries under oxidizing conditions. Simultaneous measurements of the infrared transmission and electrical conductivity of thin films were performed as a means of correlating infrared transmission with conductivity at high temperatures under various controlled atmospheres. These two measurements were found to be strongly correlated and were demonstrated to be connected to the formation and annihilation of free carriers in the thin films. A novel measurement technique was explored in which the conductance response was measured across a substrate during pulsed laser deposition of Al-doped ZnO.
The measured conductance profile as a function of time was correlated to the expected growth regimes typical of an island growth mode, and the thickness dependence of resistivity was directly observed. Additional information about the growth conditions was obtained through conductance relaxation after single pulses, performed under different growth chamber atmospheres.
by Michael J. Campion.
Ph. D.
Ph.D. Massachusetts Institute of Technology, Department of Materials Science and Engineering
40
Shimizu, Masahiro. „Space-selective Control of Functional Properties in Transparent Materials by Femtosecond Laser Irradiation“. 京都大学 (Kyoto University), 2012. http://hdl.handle.net/2433/157597.
Der volle Inhalt der Quelle
41
Bashar, Shabbir Ahsanul. „Study of transparent indium tin oxide for novel optoelectronic devices“. Thesis, King's College London (University of London), 1998. https://kclpure.kcl.ac.uk/portal/en/theses/study-of-transparent-indium-tin-oxide-for-novel-optoelectronic-devices(280e6da3-8da2-4680-9059-242b229ae1b7).html.
Der volle Inhalt der QuelleAnnotation:
Indium Tin Oxide (ITO) films were deposited on a number of semi-conductor materials using reactive r. f sputtering technique to form both rectifying Schottky and ohmic contacts. These contacts were applied in the fabrication of a number of novel optoelectronic devices: Schottky photo-diodes, transparent gate High Electron Mobility Transistors (HEMTs), heterojunction bipolar transistors (HBTs) being used as heterojunction phototransistors (HPTs), light emitting diodes (LEDs) and vertical cavity surface emitting lasers (VCSELs). A number ofthese novel devices were studied in comparatively greater detail; these were the Schottky diode and the HPT. Deposition conditions necessary to produce ITO films with high conductivity and optical transparency over a wide spectral range were studied and optimised. Separate post deposition techniques were developed to produce near ideal rectifying contacts and ohmic contacts with low contact resistance respectively. A thin film of indium (In) was also used to optimise ITO ohmic contacts to n + - GaAs substrates. Near ideal Schottky diodes were realised on n-GaAs substrates using aluminium (AI) and gold (Au) metal contacts. A simulation model was then developed and implemented to study the behaviour of current transport mechanisms over a wide temperature range. Photodiodes with ITO as the Schottky metal contact were fabricated and a study comprising of both their electrical and optical behaviour was undertaken. Relatively large geometry HBTs and HPTs were fabricated using AIGaAs/GaAs, InGaP/GaAs and InPlInGaAs systems respectively; the latter devices were first reported as a result of this study. A comparative study between devices fabricated from these systems were then made. This was followed by an appraisal of the electrical properties of each of their optical counterparts which had ITO emitter contacts. The specific photo responsivity and the spectral responses of these HPTs were analysed. In light of HPTs with transparent ITO emitter ohmic contacts, a brief examination of the merits of vertical versus lateral illumination was also made in this work. Finally a spectral response model was developed to understand and help design optoelectronic detectors comprising of single layer devices (n-GaAs Schottky photo diodes) or multiple semiconductor materials (HPTs using AIGaAs/GaAs or InPlInGaAs systems) to help predict responsivities at a given incident wavelength. As well as material properties of the constituent semiconductors, this model takes into account the specific lateral and vertical geometrical dimensions of the device.
42
Bouzid, Abdenbi. „Etude d'optimisation de l'efficacite de diffraction par des materiaux transparents : application a la realisation d'hologramme de phase avec differentes gammes de frequences spatiales“. Strasbourg 1, 1987. http://www.theses.fr/1987STR13121.
Der volle Inhalt der QuelleAnnotation:
Analyse theorique des proprietes des reseaux de phase, conditions d'etude et de realisation des element optiques holographiques pour un certain nombre d'applications. Evaluation du materiau photosensible permettant d'atteindre des efficacites de diffraction tres proches de 100 %. Mise au point d'une methode de suivi de l'evolution du materiau durant le processus de fabrication des composants. Nous pouvons determiner separement les valeurs des indices de refraction et des epaisseurs par interferometrie mach-zehnder
43
Pandurangan, Bhaskar. „Development, parameterization and validation of dynamic material models for soil and transparent armor glass“. Connect to this title online, 2009.
Den vollen Inhalt der Quelle finden
44
Denison, Timothy Allman 1970. „Optical contrast between transparent materials through external modulation of the Faraday effect“. Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/49626.
Der volle Inhalt der QuelleAnnotation:
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1998.Includes bibliographical references (leaves 99-101).
/ Timothy Allman Denison.
M.S.
45
Liu, Dun. „Femtosecond laser internal structuring of transparent materials using a spatial light modulator“. Thesis, University of Liverpool, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.540120.
Der volle Inhalt der Quelle
46
Kurita, Torataro. „Internal modification and functionality control of transparent materials by femtosecond laser irradiation“. Doctoral thesis, Kyoto University, 2021. http://hdl.handle.net/2433/264669.
Der volle Inhalt der QuelleAnnotation:
京都大学新制・課程博士
博士(工学)
甲第23388号
工博第4880号
新制||工||1763(附属図書館)
京都大学大学院工学研究科材料化学専攻
(主査)教授 三浦 清貴, 教授 田中 勝久, 教授 藤田 晃司
学位規則第4条第1項該当
Doctor of Philosophy (Engineering)
Kyoto University
DGAM
47
Spina, Giulia. „Transparent YAG and composite ceramic materials in the system Alumina-YAG-Zirconia“. Thesis, Lyon, INSA, 2012. http://www.theses.fr/2012ISAL0023.
Der volle Inhalt der QuelleAnnotation:
Dans cette étude de doctorat, de la poudre de Y3Al5O12 (YAG) a été synthétisé avec plusieurs méthodes: atomisation, synthèse de réaction et co-précipitation. Le procédé de synthèse le plus prometteur, la co-précipitation, a été optimisé pour obtenir une poudre hautement frittable, présentant une phase pure. Le traitement approprié avant frittage, comprenant calcination, efficace dispersion et séchage homogène, a été réalisé. La poudre de YAG a été dispersée avec plusieurs méthodes, avant frittage. Grâce à la technique Spark Plasma Sintering (SPS) une évaluation très rapide de l'influence des différents traitements a été réalisée. Il a été constaté que, pour une poudre obtenue avec une telle synthèse, la méthode de dispersion est cruciale afin de obtenir une transparence élevée du materiaux fritté. En raison de l'aptitude au frittage de la poudre, du traitement approprié avant frittage et de la basse température du cycle effectué par SPS, un matériau à grains fins a été obtenu. Des mesures de spectroscopie de photoélectrons (XPS) ont été effectuées sur la poudre de YAG et sur le matériaux fritté, et plusieurs differences ont été mises en évidence. Quelques hypothèses ont été faites pour expliquer les differences observées, et certains preuves supplémentaires pour les vérifier ont été mises en avant. Une poudre composite alumine-zircone-YAG a été synthétisé à partir d'une poudre d'alumine commerciale, qui a été fonctionnalisé avec chlorures de yttrium et de zirconium. Les traitements de pré-frittage appropriées ont été effectués, comprenant une calcination à basse température et une calcination "rapide", pour favoriser la germination des petits cristallites. Deux méthodes de mise en forme, coulage et pressage, ont été réalisées. Il a été constaté que le coulage permet la production de matériaux céramiques beaucoup plus homogènes. Une caractérisation mécanique préliminaire a été effectuée. Une caractérisation spectroscopique des poudres d'alumine-YAG, traités à basse et haute température, a été réalisée. Il a été mis en évidence que l'état d'hydratation des poudres varie avec la fonctionnalisation par les chlorures. La présence de sites Y sur la surface des poudres composites a été mise en évidence par XPS et à partir des spectres infrarouges (spectroscopie infrarouge par transformée de Fourier, FTIR) des échantillons soumis à des différentes pressions de monoxide de carbone (CO)In this PhD study, Yttrium aluminum garnet (Y3Al5O12, YAG) powder was synthesised with several methods, i.e. spray drying, reaction synthesis and co-precipitation. The most promising synthesis method, i.e. co-precipitation, was optimized to obtain a pure phase, highly sinterable powder. The appropriate pre-sintering processing, i.e. calcination treatment, e fficient dispersion, homogeneous drying, were performed. YAG powder was dispersed with several methods, prior to sintering. Through Spark Plasma Sintering (SPS) a very fast assessment of the influence of the various treatments was performed. It was found that, for the synthesised powder, the dispersion method is crucial to obtain a high transparency. Due to the high sinterability of the powder and to the appropriate pre-sintering treatment, a low temperature SPS cycle was performed, and a fine-grained material was obtained. X-ray Photoelectron Spectroscopy (XPS) measurements were performed on YAG powder and on the sintered material, and several di fferences were evidenced. Some hypothesis were made to explain the observed di fferences, and some additional proofs to verify them were put forward. A composite Alumina-YAG-Zirconia powder was synthesized, starting from a commercial alumina powder, which was functionalised with Yttrium and Zirconium chlorides. The appropriate pre-sintering treatments were performed, comprising a low temperature calcination and a "fast" calcination, to favour the germination of small crystallites. Two shaping methods, i.e. slip casting and pressing, were performed. It was found that slip casting allows the production of much more homogeneous ceramic materials. A preliminary mechanical characterization was performed. A spectroscopic characterization of Alumina-YAG powders, heat-treated at low and high temperatures, was performed. It was evidenced that the hydration state of the powders changes with chlorides functionalization. The presence of Y sites on the surface of the composite powders was evidenced by X-ray Photoelectron Spectroscopy and from the di fference spectra of powdered samples subjected to various CO pressures
48
Amooali, Khosroabadi Akram. „Optical and Electrical Properties of Composite Nanostructured Materials“. Diss., The University of Arizona, 2014. http://hdl.handle.net/10150/333480.
Der volle Inhalt der QuelleAnnotation:
A novel lithographic fabrication method is used to fabricate nanopillars arrays of anisotropic Ag and TCO electrodes. Optical and electrical properties of the electrodes including bandgap, free carrier concentration, resistivity and surface plasmon frequency of different electrodes can be tuned by adjusting the dimensions and geometry of the pillars. Given the ability to tune the nonlocal responses of the plasmonic field enhancements, we attempt to determine the nature of the effective refractive index profile within the visible wavelength region for multi-layer hybrid nanostructures. Knowledge of the effective optical constants of the obtained structure is critical for various applications. nanopillars of TCO\Ag core shell structures have been successfully fabricated. The Maxwell-Garnett mixing law has been used to determine the optical constants of the nanostructure based on spectroscopic ellipsometry measurements. Simulated reflection spectra indicate a down shift in the Brewster angle of the pillars resulting from the reduction in the effective refractive index of the nanostructure. Two plasmonic resonances were observed, with one in the visible region and the other in the IR region. Plasmon hybridization model is used to describe the behavior of metal and metal oxide core shell nanostructured electrodes. Different charge density distributions around the pillars determine the plasma frequency which depends on the core and surrounding media dielectric constants. Finite Difference Time Domain (FDTD) simulation of different structures agree well with experiment and help us to understand electric field behavior at different structures with different geometries and dielectric constants. Plasmonic Ag nanopillar arrays are effective substrates for surface enhanced Raman spectroscopy (SERS). An enhancement factor up to 6 orders of magnitude is obtained. Monolayers of C60 is deposited on the Ag nanopillars and the interface of C60/Ag is studied which is important in optoelectronic devices. Electron delocalization between C60 and Ag is confirmed.
49
Scenev, Vitalij. „Electronic properties of graphene and other carbon-based hybrid materials for flexible electronics“. Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät, 2014. http://dx.doi.org/10.18452/17069.
Der volle Inhalt der QuelleAnnotation:
In dieser Arbeit wurden einerseits die elektronischen Eigenschaften von Graphenen und andererseits die Verwendung von Graphenen und Kohlenstoff-basierten Hybridmaterialien als transparente Elektroden untersucht. Entsprechend ist der erste, umfangreichere Teil der Arbeit Grundlagen-orientiert und fokussiert auf die elektrostatische Wechselwirkung zwischen Graphen und dem Substrat Glimmer. Der zweite, kleinere Teil befasst sich mit der Entwicklung leitfähiger Tinten auf der Basis von Graphenen und anderen Kohlenstoff-basierten Hybridmaterialien für Anwendungen in der druckbaren Elektronik, insbesondere für die Herstellung transparenter Elektroden. Graphen auf Glimmer ist ein sehr wohldefiniertes System, in dem das Graphen über mehrere Quadratmikrometer atomar flach ist. Schichtdickenabhängige Variationen des Oberflächenpotentials von einzel- und mehrlagigen Graphenen auf Glimmer wurden mittels Kelvin Probe Rasterkraftmikroskopie untersucht. Damit konnte die elektrostatische Abschirmlänge von Graphen auf Glimmer bestimmt werden. Lokale Variationen des Oberflächenpotentials innerhalb einer Graphenlage, verursacht durch eingeschlossene Wasserschichten zwischen Graphen und Glimmer, wurden mit Rasterkraftmikroskopie, elektrostatischer Rasterkraftmikroskopie und der Raman-Spektroskopie untersucht. Dies ermöglichte es, die Dotierung von Graphen durch eingeschlossene Wasserschichten zu quantifizieren. Außerdem wurde gezeigt, dass Graphen auf molekular modifiziertem Glimmer lokal auf der Nano-Skala dehnbar ist. Dabei wurde der Glimmer durch das Aufbringen von dendronisierten Polymeren verschiedener Generationen auf Nanometer-Skala modifiziert. Dies eröffnet neue Möglichkeiten, die lokalen elektronischen Eigenschaften von Graphen durch Dehnung zu kontrollieren.Schließlich wurden Kohlenstoff-basierte leitfähige Tinten hergestellt, daraus transparente Elektroden hergestellt, und die Formulierungen der Tinten für das Drucken auf Plastiksubstrate optimiert.This work focusses on the electronic properties of graphene on the one hand, and on the application of graphenes and other carbon-based hybrid materials for transparent electrodes on the other hand. Accordingly, the first part of the work, which is the larger one, is of fundamental nature and focusses on the electronic interaction between graphene and mica as a substrate. The second, smaller part deals with the design of novel conductive inks based on graphene and other carbon-based hybrid materials for applications in printed electronics, in particular for the production of transparent electrodes. Graphene on mica is a very well defined system, which provides atomically flat graphene extending over several square micrometers. Layer-dependent surface potential variations of single and few layered graphenes on mica were probed with Kelvin Probe Force Microscopy. This allowed to estimate the screening length of graphene on mica. Local variations of the surface electrostatic potential above single layer graphene, originating from confined fluid interfacial monolayers of water between the mica and the graphene, were monitored with Scanning Force Microscopy, Electrostatic Scanning Force Microscopy and Raman spectroscopy. This allowed to quantify the doping of graphene by the confined water layers. Exfoliation of graphene onto adsorbed nanostructures on mica allowed to control the strain of graphene at the nano-scale. Nanostructuring was achieved by first coating mica with submonolayers of dendronized polymers of different generations and subsequently depositing graphene. This approach provides new opportunities for the control of the electronic properties of graphene by strain.Finally, novel conducting carbon-based inks were designed and transparent electrodes were fabricated therefrom. The formulations of the inks were optimized for printing on plastic substrates.
50
Antoine, Donley. „Optical Transparent Pmma Composite Reinforced By Coaxial Electrospun Pan Hollow Nanofibers“. Thesis, University of North Texas, 2013. https://digital.library.unt.edu/ark:/67531/metadc271772/.
Der volle Inhalt der QuelleAnnotation:
Electrospinning has been recognized as an efficient technique for the fabrication of polymer fibers. These electrospun fibers have many applications across a broad range of industries. In this research, optical transparent composites were successfully fabricated by embedding polyacrylonitrile (PAN) hollow nanofibers into poly (methyl methacrylate) (PMMA) matrix. The hollow PAN nanofibers were prepared by coaxial electrospinning. The PAN was used as the shell solution, and the mineral oil was used as the core solution. The resulting fibers were then etched with octane to remove the mineral oil from the core. The hollow PAN fibers were then homogeneously distributed in PMMA resins to fabricate the composite. The morphology, transmittance and mechanical properties of the PAN/PMMA composite were then characterized with an ESEM, TEM, tensile testing machine, UV-vis spectrometer and KD2 Pro Decagon device. The results indicated that the hollow nanofibers have relatively uniform size with one-dimensional texture at the walls. The embedded PAN hollow nanofibers significantly enhanced the tensile stress and the Young's modulus of the composite (increased by 58.3% and 50.4%, respectively), while having little influence on the light transmittance of the composite. The KD2 Pro device indicated that the thermal conductivity of the PMMA was marginally greater than the PAN/PMMA composite by 2%. This novel transparent composite could be used for transparent armor protection, window panes in vehicles and buildings, and airplane windshield etc.