Дисертації з теми "Pt-free"
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Eckardt, Markus [Verfasser]. "ORR activity and stability of Pt-based and Pt-free catalysts for PEMFC applications / Markus Eckardt." Ulm : Universität Ulm, 2020. http://d-nb.info/1203716257/34.
Повний текст джерелаMarzorati, S. "PT-FREE NANO- AND MICRO-STRUCTURED CARBONS FOR ELECTROCHEMICAL OXYGEN REDUCTION REACTION." Doctoral thesis, Università degli Studi di Milano, 2015. http://hdl.handle.net/2434/332529.
Повний текст джерелаManandhar, Sudha. "Free Radical Induced Oxidation, Reduction and Metallization of NiSi and Ni(Pt)Si Surfaces." Thesis, University of North Texas, 2010. https://digital.library.unt.edu/ark:/67531/metadc31542/.
Повний текст джерелаZhu, Qing Shih Wei-Heng Shih Wan Y. "Characterization and application of piezoelectric microcantilever sensors fabricated from substrate-free PMN-PT layers /." Philadelphia, Pa. : Drexel University, 2008. http://hdl.handle.net/1860/2967.
Повний текст джерелаCiubotariu, Dragos. "Design, Modeling, Fabrication and Control of PMN-PT Piezoelectric Systems." Thesis, Besançon, 2016. http://www.theses.fr/2016BESA2048/document.
Повний текст джерелаThis work proposes the use of a novel material, called PMN-PT, that futher aids the miniaturizationof complex systems used in different technologies. The work is presented within the collaborativeframework of two projects, MIOP and ADMAN. The end-needs account for actuators capable ofdelivering high displacement, while maintaining system simplicity and reliability. The focus is onthe versatility of the PMN-PT piezoelectric material, due to its electro-mechanical properties. Thework includes an overview on what influences the electro-mechanical properties focusing on twodifferent, though very potent cuts: anisotropic [011] and longitudinal [001]. They were chosen forgenerating large displacement and high dynamics with small volume. For PMN-PT[001] a cantileverstructure was studied, for which the model was improved taking into account the material specificities.Displacements and forces were found to be superior to a similarly dimensioned PZT actuator, whilsthaving reduced non-linearities. This is exemplified with a 6 DoF capable microgripper. The PMNPT[001] longitudinal cut based actuator study follows. This is done by using PMN-PT as a simple,easy to integrate, bulk actuator. The findings demonstrate the improvements PMN-PT can bringto micro-spectrometry and image correction with micro-mirror displacement. A bulk PMN-PT microactuator was integrated into a MOEMS compatible structure and presented
Maier, Jan Richard [Verfasser], Todd B. [Gutachter] Marder, and Bernd [Gutachter] Engels. "Investigations of Metal-free Cannibalistic Hexadehydro-Diels-Alder and Pt-catalyzed Dimerization Reactions of Linked Aryl Bisdiynes / Jan Richard Maier ; Gutachter: Todd B. Marder, Bernd Engels." Würzburg : Universität Würzburg, 2021. http://d-nb.info/1236548043/34.
Повний текст джерелаGaddam, Sneha Sen. "Effect of Fluorine and Hydrogen Radical Species on Modified Oxidized Ni(pt)si." Thesis, University of North Texas, 2010. https://digital.library.unt.edu/ark:/67531/metadc28421/.
Повний текст джерелаMartins, Thamiris Franco. "A construção da imagem de Dilma Rousseff (PT) na esfera midiática: dissonâncias e convergências narrativas entre a presidente e a candidata à reeleição." Universidade Federal de Juiz de Fora, 2016. https://repositorio.ufjf.br/jspui/handle/ufjf/1274.
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A partir das relações de poder que se estabelecem entre o campo político e a instância comunicativa midiática, a dissertação tem como ponto de partida o conceito de campanha permanente, definido como o uso dos recursos disponíveis no trabalho por parte dos atores políticos (governos, partidos, congressistas ou líderes), a fim de construir e manter o apoio popular. A pesquisa desenvolve um estudo sobre a construção da imagem de Dilma Rousseff, do partido dos trabalhadores (PT), em três instâncias: pronunciamentos em rede de TV, Horário Gratuito de Propaganda Eleitoral (HGPE) e jornal Folha de S. Paulo. Busca-se verificar como foi trabalhada a campanha, permanente, na função de Presidente da República, eleita em 2010 e de candidata à reeleição em 2014. Como corpus de análise, são analisados, primeiramente, os espaços institucionais ocupados como presidente da República, tomando como recorte os pronunciamentos em Cadeia Nacional de Rádio e TV (CNRT), durante seu primeiro mandato. Secundariamente, procura-se verificar se a imprensa, por meio da cobertura dos pronunciamentos, projetou uma imagem negativa, positiva ou neutra de Dilma Rousseff na posição de presidente, tomando como recorte as notícias publicadas pelo jornal Folha de S. Paulo. Como terceira dimensão de análise, são investigados os HGPEs de 2014. Como estratégia metodológica, recorreu-se à Análise de Conteúdo de Bardin (1977), a fim de analisar separadamente os objetos e depois identificar os pontos de confluência e os aspectos dissonantes. Identificam-se dois momentos no governo Dilma: o de alta popularidade até as manifestações de junho de 2013, e a fase posterior, com queda da aprovação e uma disputa acirrada na eleição de 2014, quando saiu vitoriosa com um percentual muito reduzido de votos em relação ao candidato Aécio Neves do Partido Social da Democracia Brasileira (PSDB). Houve mais pontos de confluências no primeiro momento entre o discurso da petista e a cobertura da imprensa. O segundo período foi conturbado e houve uma cobertura mais negativa e crítica por parte da mídia. A comunicação eleitoral foi uma forma de buscar resgatar as ações do governo, havendo uma intensa propaganda negativa de ataques entres os adversários.
From the power relations that are establish between political field and the media communication system, this dissertation has as a key concept ‘the permanent campaign’, defined as the implementation of the any available resources for the political actors during their work (government, political parties, congressman or leaders) aiming to obtain and keep popular support. This research develops a study about the making of the image of Dilma Rousseff (PT) in three situations: pronouncement in TV network, HGPE and Folha de S. Paulo newspaper. This paper tries to verify how the permanent campaign has been undertaken as president of the Brazilian Republic, elected in 2010, and as a candidate running for reelection in 2014. As empirical data, firstly are analysed the institutionalized spaces occupied as president of the Brazilian Republic, defining as analytical material the pronouncements in National Network of Radio and Television (CNTR, in portuguese) during her fist mandate. Secondly, it tries to verify if the press, through its pronouncements coverage, created a negative, positive or neutral image of Dilma Rousseff in her position as president, taken as empirical data the news published by Folha de S. Paulo newspaper. As third material data, it will be analysed the programs of Free Political Advertising Time (HGPE, in portuguese) in 2014. As methodological strategy, we recurred to the Content Analysis (Bardin, 1977) with the goal of analysing separately the objects and then identify the convergence and dissonant aspects. We can identify two different moments in Dilma’s government: high popularity until june 2013 manifestations and the subsequent period with fall of approval and fierce competition on the 2014 election, when she won the elections with a minor percentage of votes in relation to the candidate Aécio Neves (PSDB). There were more confluence aspects in the first period between the president’s pronouncements and the media coverage. The second moment was troubled and there was a more negative and critical coverage by the media. The electoral communication was an attempt to retrieve the governments’ actions and there was an intense negative propaganda of attacks between the candidates.
Li, Chun-Ting, and 李君婷. "Dye-sensitized Solar Cells:Study of Pt-free Counter Electrodes and Iodide-free Electrolytes." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/a2622n.
Повний текст джерела國立臺灣大學
化學工程學研究所
103
This dissertation aimed to systematically develop Pt-free counter electrodes (CEs) and to design a novel iodide-free electrolyte for the dye-sensitized solar cells (DSSCs) with low-costs and highly cell efficiencies (η’s). This dissertation is divided into two parts: (1) Pt-free CEs (Chapter 3~Chapter 7) and (2) iodide-free electrolyte (Chapter 8). In the case of Pt-free CEs, we aim to reduce the costs of the DSSCs using various electro-catalysts for completely replacing the expensive Pt via the simple, non-vacuum, and low-cost fabrication processes. Accordingly, three types of Pt-free composite films were studied using a standard iodide electrolyte. (I) Transition metallic compound-type CEs, including the composite film of TiS2/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (TiS2/PEDOT:PSS) in Chapter 3, the composite films of Si3N4/PEDOT:PSS, SiO2/PEDOT:PSS, SiS2/PEDOT:PSS, SiSe2/PEDOT:PSS in Chapter 4, and the composite films of Zn3N2/PEDOT:PSS, ZnO/PEDOT:PSS, ZnS/PEDOT:PSS, ZnSe/PEDOT:PSS in Chapter 5, were indivitually investigated. In a composite film, the transition metallic compound nanoparticles were separately used to provide attractive electro-catalytic abilities and large active areas for I3- reduction; among those NPs, TiS2, Si3N4, SiS2, SiSe2, Zn3N2 and ZnSe were applied in DSSCs for the first time. Among them, the cell with Zn3N2/PEDOT:PSS CE reached a higher η than that of Pt-based cell. (II) Carbonaceous-type CEs, i.e., the composite films of nano-porous carbon black nanoparticles/ sulfonated-poly(thiophene-3-[2-(2-methoxyethoxy)-ethoxy]-2,5-diyl) (CB NPs/s-PT), were investigated in Chapter 6 to provide large surface area, fast eletrolyte penetratoin, and rapid reaction rate for I3– reduction. When a composite film contains 5 wt% CB NPs, the pertinent DSSC reached best η of 9.02%, which is even higher than that of Pt-based DSSC. The s-PT is introduced as a novel thiophene-based water-soluable conducting polymer for CE in DSSC for the very first time. Under weak sunlight, the cell with CB NPs/s-PT composite CE still maintains good performance, indicating its good compatibility at both outdoor or indoor electronics. (III) Conducting polymer type CEs, including poly(3,4-ethylenedioxythiophene) (PEDOT) and six different ionic-liquid-doped PEDOT films were systematically investigated in Chapter 7. Six different ionic liquids containing three imidazolium cations with different alkyl chains (–C2H5, –C6H13, –C10H21) and four anions (BF4−, PF6−, SO3CF3−, TFSI−) were used as the chemical dopants to increase the surface area of PEDOT films and to ehance the conjugation of the PEDOT films, respectively. Among them, the cell with HMIPF6-doped PEDOT and HMITFSI-doped PEDOT CEs reached higher η’s than that of Pt-based DSSC. In brief, this dissertation explores four Pt-free composite films of Zn3N2/PEDOT:PSS, HMIPF6-doped PEDOT, HMITFSI-doped PEDOT, and CB NPs/s-PT are a promising substitutions of Pt due to their outstanding properties, i.e., good electro-catalytic ability for I3– reduction, low-cost, simple preparation process, and easy for large-scale production. In the case of iodide-free electrolyte, we designed a novel dual-channel ionic liquid compound (Chapter 8), 1-butyl-3-{2-oxo-2-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]ethyl}-1H-imidazol-3 -ium selenocyanate (ITSeCN), to further improve the cell effiency of DSSCs. ITSeCN is designed to contain dual redox channels of imidazolium-functionalized TEMPO (cationic redox mediator) and selenocyanate (anionic mediator). Thereby, the ITSeCN shows the favorable redox natures, which gave more positive standard potential, larger diffusivity, and better kinetic heterogeneous rate constant than those of iodide. To further investigate a suitable electro-catalytic material for triggering the redox of ITSeCN mediator, several materials were used: (1) Pt (metal type), (2) PEDOT (conducting polymer type), (3) CoSe (transition metallic compound type), and (4) carbon black (carbonaceous type) films were chosen to represent four types of electro-catalytic materials in DSSCs. Finally, the DSSCs with PEDOT and CoSe CEs achieved better performance than that of the Pt-based DSSC. Therefore, it can be infered that the transition metallic compound type CEs would be more suitable for our new synthesized-ITSeCN mediator than the others.
Huang, Yi-June, and 黃奕鈞. "Pt-Free Nanostructural Electrocatalysts for Dye-Sensitized Solar Cells." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/2h8bax.
Повний текст джерела國立臺灣大學
化學工程學研究所
107
This dissertation aimed to systematically study Pt-free and TCO-free counter electrodes (CEs) with low-costs and highly cell efficiencies (η’s). This dissertation is divided into two parts: (1) Pt-free CEs (Chapter 3 and Chapter 4) and (2) Pt-free and TCO-free CEs (Chapter 5 and Chapter 6). In the case of Pt-free CEs, we aim to reduce the costs of the DSSCs using various electro-catalysts for completely replacing the expensive Pt via the simple, non-vacuum, and low-cost fabrication processes. Accordingly, three types of Pt-free composite films were studied using a standard iodide electrolyte. (I) Transition metallic compound-type CEs, i.e. CoSe2/CoSeO3 with nanocube (NC), nanorod (NR), and nanoparticle (NP) structures in Chapter 3, the composite films of CoSe2/CoSeO3 with hierarchical urchin-like structure in Chapter 4, were indivitually investigated. In the composite film, the different nanostructures were separately used to provide attractive electro-catalytic abilities and large active areas for I3- reduction. (II) Transition metallic and conducting polymer type CEs, i.e. MoSe2 NS/PEDOT:PSS in Chapter 5, were investigated to provide large surface area, fast eletrolyte penetration, well adhesion, and rapid reaction rate for I3- reduction. (III) Carbonaceous-type CEs, i.e. pristine monolithic carbon aerogel (CA-O, CA-Q, CA-F, CA-C, and CA-G) in Chapter 6, were investigated by controlled resorcinol (R)/formaldehyde (F) and resorcinol (R)/sodium carbonate (C) molar ratios. In the case of Pt-free and TCO-free CEs. In the case of Pt-free and TCO-free CEs, the classic TCO substrate is replaced by Ti foil and carbon aerogel for low-cost, simple preparation process, and large-scale production. (I) Ti foil substrate collocate with MoSe2 NS/PEDOT:PSS, which presents a higher η of 8.51 ± 0.05%, as compared to a lower η of 8.21 ± 0.02% using the Pt-coated Ti foil CE. (II) Carbon aerogel replace traditional CEs based on the Pt/FTO/glass in DSSCs. The DSSCs using the as-prepared CA-C CE gave the best η of 9.08 ± 0.01%, among all the CA CEs. In brief, this dissertation explores three Pt-free composite films of CoSe2/CoSeO3, MoSe2 NS/PEDOT:PSS, and CA are a promising substitutions of Pt due to their outstanding properties, i.e., good electro-catalytic ability for I3– reduction, low-cost, simple preparation process, and easy for large-scale production.
Alam, MD Zafir. "Tensile Behavior Of Free-Standing Pt-Aluminide (PtAl) Bond Coats." Thesis, 2012. http://hdl.handle.net/2005/2531.
Повний текст джерелаLin, Yu-Chang, and 林佑錩. "Buckypapers as Pt-Free Counter Electrodes for Dye-Sensitized Solar Cells." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/93999139851426186260.
Повний текст джерела東海大學
物理學系
103
Photoelectrochemical dye-sensitized solar cells (DSCs) have attracted much interest in the field of sustainable green energy. However, their counter electrodes (CEs) usually fabricated by the noble metal Pt. To obtain the alternative Pt-Free CEs for DSCs is desirable for the wide deployment of DSCs. Buckypapers (BPs) are prepared in the random and highly interpenetrative configuration of multi-walled carbon nanotubes (MWCNTs), and it has high porosity and conductivity. In this study, BPs are unitized as the CEs for DSCs. From the results of electrochemical impedance spectroscopy (EIS) analysis, the charge transfer rate (fct) of BP-DSC (9357 Hz) is greater than that of Pt-DSC (698 Hz) and the recombination rate (frec) of BP-DSC (1.1 Hz) is lower than that of Pt-DSC (1.7 Hz), indicating the BP-CE provides an efficient reduction and suppresses the recombination in DSC. For the results of cyclic voltammetry (CV), the reduction current [I(Red1)] of BP electrode (-0.956 mA) is greater than that of Pt electrode (-0.083 mA). The results of EIS and CV measurement reveal that the reduction reaction of BP electrode is improved because of its extreme electroactive surface area, and this improvement suppresses the recombination rate in DSCs. Accordingly, BP-DSCs show a high open-circuit voltage (Voc) and fill factor (FF) in power-dependent J-V characterization. As the results, BP-DSCs exhibit a higher enhancement in PCE than that of Pt-DSCs and show the PCE comparable to Pt-DSCs under 100 mW/cm2 illumination.
Wang, Wei-Yan, and 王偉彥. "A STUDY OF DSSCS BASED ON TCO-PT-FREE FLEXIBLE COUNTER ELECTRODES." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/c62e4f.
Повний текст джерела大同大學
化學工程學系(所)
102
In this study, we first utilize the high temperature reflux mode to well mix the CNT and PP and followed by thermal compression to prepare the CNT/PP thin plates as a Pt-free and TCO-free CE for DSSCs. After that, to further carry out the test of materials characterizations and electrochemical activity. Although the cell efficiency of DSSCs using CNT/PP based CEs was still much lower than that of DSSC with Pt/FTO CE, it is showed the excellent sheet resistance and flexibleness. Therefore, we used the CNT/PP to replace the FTO glass as a substrate. In order to enhance the photovoltaic performance, we further deposited PEDOT thin film on flexible CNT/PP plates via electropolymerization method as a PEDOT-CNT/PP CE. From a series of results and discussion, the composites of PEDOT-CNT/PP exhibited excellent electrocatalytic activity and low charge transfer resistance. On the other hand, after the optimization of flexible test, the CNT/PP plate prepared in the ratio of CNT/PP with 43% possessed the highest bending ability. However, the power conversion efficiency of the PEDOT coated on CNT/PP with 43% is 6.09%, which is lower than Pt/FTO CE (6.69%). In the bending characteristics, the composites of PEDOT-CNT/PP showed the excellent potential as a low-cost and flexible composites CE in DSSCs.
Huang, Chiu-Ping, and 黃秋萍. "Highly active Pt-free catalysts membrane electrode assembly in Alkaline Exchange Membrane Fuel Cells." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/4jgk8k.
Повний текст джерела曾昭瑋. "Fabrication and Characteristics of Au Free Fully Cu InP HBT Using Pt as Diffusion Barrier." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/67275902326423999781.
Повний текст джерела國立交通大學
材料科學與工程系所
92
The fully Cu metallization InP heterojunction bipolar transistor (HBT) using Platinum (Pt) as diffusion barrier has been successfully fabricated and demonstrated in this study. The InP HBT uses Ti/Pt/Cu for n-type, Pt/Ti/Pt/Cu for p-type ohmic contacts metals and Ti/Pt/Cu for interconnect metals with Pt as the diffusion barrier. Both the n+-InGaAs/Ti/Pt/Cu/Cr multilayer structure and GaAs/SiNx/Ti/Pt/Cu/Cr structure were stable up to 350oC 30 min annealing as judged from data of AES, XRD, and AFM and from the measurement of the sheet resistance. Current accelerated stress test was conducted on the device with current density (JC) of 80 kA/cm2 for 24 hours, the current gain showed no degradation after the high current stress. The devices were also thermally annealed at 200oC for 1 and 3 hours and showed no dramatic changes. Overall, we have successfully demonstrated that fully Cu metallization InP HBT can be achieved by using Pt as the diffusion barrier and Ti/Pt/Cu and Pt/Ti/Pt/Cu as the ohmic contacts.
Chen, Szu-Chien, and 陳思蒨. "Applications of PANI and PEDOT as Cathodic Catalysts for Pt-free Dye-Sensitized Solar Cells." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/51424854601972144035.
Повний текст джерела國立中央大學
化學研究所
99
Dye-Sensitized Solar Cells (DSSCs) are attractive the third generation thin film solar cells due to their low cost, light weight, colorful, fabricated easily and flexible. Generally, platinum is employed as a catalyst for the cathode in DSSC to catalyze the reduction reaction (I3- to 3I-) of the electrolyte. However, platinum is one of the most expensive materials on the earth. The preparation of Pt counter electrode at high temperature also increases the cost and difficulty in fabricating large-size device. Therefore, extensive studies have been carried out for developing other cheaper materials to replace Pt in DSSC. In this study, we investigated the performance of DSSCs using polyaniline (PANI) or poly(3,4-ethylenedioxythiophene) (PEDOT) as a catalyst on the counter electrode. We found that HFIP (Hexafluoroisopropanol) is a very good solvent for PANI and PEDOT powder. PANI and PEDOT counter electrode with large surface area and good conductivity can be made from PANI/HFIP and PEDOT/HFIP solution simply by spin coating at room pemperature, and the heating process is unnecessary. DSSC uses PANI/ FTO as a counter electrode exhibits an efficiency of 7.77 % with CYC-B11 as a sensitizer ( Pt:8.83 % ). Nevertheless, the efficiency of DSSC used PANI-SO4-HFIP CE (made from the H2SO4-Doped PANI/HFIP solution by spin coating the film on FTO) as counter elctrode achieves the highest efficiency of 8.76 %,which is comparable to that (8.83 %) of Pt-based DSSC under the same fabrication and measurement conditions. Furthermore, dispersing of PEDOT powder in HFIP was also used to prepare PEDOT counter electrode (PEDOT CE) by spin coating. The efficiency of PEDOT CE-based DSSC with CYC-B11 as sensitizer is 8.98 % ( Pt:8.74 % ). The results proved that conjugated polymers are good materials for replacing Pt as a counter electrode catalyst for DSSC.
Hsiang, Mao-Yu, and 毛鈺翔. "Study on Highly Active Pt-free NiRu Electrocatalyst for Alkaline Hydrogen Oxidation and Evolution Reactions." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/f58p75.
Повний текст джерела國立臺灣科技大學
化學工程系
105
Fuel cells have been considered as a potential candidate for alternative energy generation system. Unfortunately, the use of high cost precious Pt catalyst limits its wide spread application. In this study, CNT supported Ni-Ru bimetallic catalyst was successfully synthesized by using hydrothermal method and the catalyst loading can be well controlled about 22-25% as well as good reproducibility, which is applied to hydrogen oxidation reaction (HOR) and hydrogen gas precipitation reaction (HER) under alkaline conditions. The size of the catalyst was observed from 2 to 3 nm by TEM, and the nanocatalyst are well dispered on CNT. The results of X-ray absorption spectra indicate that the catalyst has a high alloy extent after ammonia heat treatment, nickel-nitride bonding is confirmed by XPS. The electrochemical test for alkaline HOR and HER shows that the Ni-Ru/C catalyst after ammonia heat treatment at 4500C an possesses activity comparable to Pt/C and much better than Ni/C and Ru/C catalysts while the cost of Ni-Ru/C is much lower than Pt/C. Due to the excellent activity of alkaline HOR and HER for as-prepared Ni-Ru/C catalyst which is well-matched to Pt/C catalyst, the bi-functional property may be included in the catalyst. In the further discussion of the stability test, the stability of the test using the constant voltage test, after 12 hours of testing time, after ammonia heat treatment catalyst, the HOR and HER, 4%(Pt/C 23%) and 11% (Pt/C 5.5%) decay, respectively, has a very high stability.
Maier, Jan Richard. "Investigations of Metal-free Cannibalistic Hexadehydro-Diels-Alder and Pt-catalyzed Dimerization Reactions of Linked Aryl Bisdiynes." Doctoral thesis, 2021. https://doi.org/10.25972/OPUS-24041.
Повний текст джерелаDas einleitende Kapitel gibt einen Überblick über den aktuellen Stand des mechanistischen Verständnisses der Hexadehydro-Diels-Alder (HDDA)-Reaktion. Mit der rasanten Entwicklung der HDDA-Reaktion seit ihrer ersten Entdeckung im Jahr 1997 wurde die Frage diskutiert, ob ein konzertierter oder ein schrittweiser Mechanismus die thermisch aktivierte Bildung von ortho-Benzin aus einem Diin und einem Diinophil besser beschreibt. Mechanistische und kinetische Untersuchungen konnten zeigen, dass es sich hierbei nicht um eine Schwarz-Weiß-Situation handelt, da schon kleine Änderungen das Gleichgewicht verändern können. In Kapitel 2 dieser Arbeit wurde der katalytische Prozess, der von 1,11-Bis(p-tolyl)undeca-1,3,8,10-tetrain zu vollständig substituierten Naphthalin- und Azulen-Derivaten führt, über zwei verschiedene platinkatalysierte Dimerisierungspfade untersucht. In Kapitel 3 wurde die kannibalistische Selbsteinfangreaktion eines ortho-Benzin-Derivats untersucht, das aus 1,11-Bis(p-tolyl)undeca-1,3,8,10-tetrain in einer HDDA-Reaktion erzeugt wurde. Ohne Zugabe eines spezifischen Einfangmittels wird das hochreaktive Benzin von einem anderen Bisdiin-Molekül in mindestens drei verschiedenen Modi eingefangen. In Kapitel 4 wird der direkte UV/VIS-spektroskopische Nachweis für die Existenz eines o-Benzins in Lösung berichtet und die Dynamik seiner Bildung in einer photoinduzierten Reaktion aufgezeigt. Zu diesem Zweck wurde 1,11-Bis(p-tolyl)undeca-1,3,8,10-tetrayne mittels Femtosekunden-Transienter-Absorptionsspektroskopie im ultravioletten/sichtbaren Bereich untersucht. In Kapitel 5 wurden nach der Isolierung und Charakterisierung der in Kapitel 3 diskutierten Reaktionsprodukte weitere Spezies identifiziert, die aus Reaktionen des hochreaktiven ortho-Benzin-Derivats resultieren
Ruz, Sichem Guerrero. "Activity in-situ IR and EXAFS spectroscopy studies, and Monte Carlo simulation of the preferential oxidation of carbon monoxide on Nb-promoted Pt/A12O3 catalysts and Pt-free metal oxides catalysts." 2007. http://etd.nd.edu/ETD-db/theses/available/etd-12202007-161930/.
Повний текст джерелаThesis directed by E. E. Wolf for the Department of Chemical and Biomolecular Engineering. "December 2007." Includes bibliographical references (leaves 196-214).
Lee, Kun-Mu, and 李坤穆. "A Study on Dye-Modified TiO2 Electrode, Gel Polymer Electrolyte and Pt-Free Counter Electrode for Dye-Sensitized Solar Cells." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/19070914806518361549.
Повний текст джерела國立臺灣大學
高分子科學與工程學研究所
97
The main purpose of this thesis is to investigate the behaviors of new approaches in electrodes (working and counter), sensitizers and gel polymer electrolytes for dye-sensitized solar cells (DSSCs) and discussing the influences on the cell performance and stability of DSSCs. In the first part of this thesis (Chapter 2 and 3), the optimization of solar energy conversion efficiency of DSSCs was investigated by the tuning of TiO2 photoelectrode’s morphology. Double-layered TiO2 photoelectrodes were designed by the coating of TiO2 suspension incorporated with low and high molecular weight poly(ethylene glycol) as a binder. Among four types of TiO2 electrodes, the P2P1 showed the highest efficiency under the conditions of identical film thickness and constant irradiation. This can be explained by the larger pore size and higher surface area of P2P1 TiO2 electrode than the other materials and these two factors assist for the facile transport of I3-/I- ion couple through the TiO2 matrix. The best efficiency (h) of 9.04% for a solar cell was obtained by introducing the light scattering particles to the TiO2 electrode measured under AM 1.5G. As for the part of low-temperature fabricated DSSC, the TiO2 film with the TTIP/TiO2 molar ratio of 0.08 has the best conduction. Meanwhile, the charge transport resistance at the TiO2/dye/electrolyte interface increased as a function of the MWCNT concentration, ranged from 0.1 to 0.5 wt%, due to a decrease in the surface area for dye adsorption. The DSSC with the TiO2 containing 0.1 wt% of MWCNT resulted in a JSC of 9.08 mA/cm2 and a cell conversion efficiency of 5.02 %. On the other hand, TiO2 film prepared by using binder-free TiO2 paste which developed by Prof. Miyasaka’s group was also used in plastic DSSC to optimal the SJW-E1 dye which synthesized by Prof. Wu’s group. The effects of TiOx buffer layer and co-adsorbents as well as long-term stability of plastic DSSCs were investigated. The TiOx buffer layer not only benefited the adhesion between TiO2 thin film and ITO/PEN substrate but also reduced the electron recombination, resulting in the improvement of the FF and conversion efficiency of cells. The optimized solar cell based on SJW-E1 showed a high efficiency of 6.31 % at 100 mW/cm2 (AM 1.5G), and SJW-E1 based solar cell showed a better stability than that of N719 based after 500 h light soaking test. In the second part of this thesis (Chapter 4), the co-sensitization of dyes for the complementary in the spectral characteristics in plastic DSSCs was investigated. Two co-sensitization systems for the plastic DSSCs, including N719/FL and black dye/FL showed enhanced photovoltaic performances compared with that of each dye individually. The optimal conversion efficiencies of N719/FL and black dye/FL DSSCs reached 5.10 % and 3.78 %, respectively, which were higher than that of individual sensitizers. However, for the system co-sensitized with FL and Chl-e6, the cell performances only lay in between that of each dye. From the EIS analysis, the characteristic frequencies (C.F.) at TiO2/dye/electrolyte interface for N719/FL and black dye/FL are kept the same or lower than that of individual dyes. While for the FL /Chl-e6 co-sensitized DSSCs, the C.F. were higher than that based on only FL, indicating that they had shorter electron lifetime in the TiO2 electrode after co-sensitization. In the third part of this thesis (Chapter 5), two kinds of gel polymer electrolytes were developed and used in DSSCs. At the beginning, it was found that the donor number of solvent in electrolyte is the one of the key factors that effect the photovoltaic performance of DSSC. Meanwhile, the quasi-solid state DSSCs were fabricated with polyvinyidene fluoride-co-hexafluoro propylene (PVDF-HFP) in methoxy propionitrile (MPN) as gel polymer electrolyte (GPE), tetrabutylammonium iodide/iodine as redox couple, 4-TBP as additive and nano-silica as fillers. The energy conversion efficiency of the cell with 5 wt% PVDF-HFP is comparable to that one obtained in liquid electrolyte system. Solar cell containing PVDF-HFP with 0.8 M of TBAI and 0.12 M of I2 shows maximum photocurrent. Moreover, the addition of 1wt% nano-silica is found to improve the at-rest durability and the performance of the solar cell. A photocurrent of 14.04 mA/cm2, a VOC of 0.71 V and an overall conversion efficiency of 5.97 % under 100 mW/cm2 irradiation was observed for the best performance of a solar cell in this work. On the other hand, the ionic conductivities and performances of DSSCs of GPEs prepared by in situ polymerization with different cross-linkers were investigated. The poly(imidazole-co-butylmethacrylate)-based GPE containing the B4Br cross-linker showed a higher ionic conductivity, due to the formation of micro-phase separation that resulted in an increase of ion transport paths in the GPE. Moreover, a co-adsorbent, (4-pyridylthio) acetic acid, co-adsorbed with N3 dye on the TiO2 electrode not only reduced dye aggregation, but also reacted with the cross-linkers in the GPE at the TiO2/GPE interface after gelling, thus the value of JSC significantly increased from 7.72 to 10.00 mA/cm2. In addition, in order to reduce the ionic diffusion resistance within the TiO2 electrode, incorporation of monodispersed PMMA in the TiO2 paste was considered. With the optimal volume ratio of PMMA/TiO2 (v/v = 3.75), the micro-porous TiO2 electrode exhibited larger pores (ca. 350 nm) uniformly distributed after sintering, and the ionic diffusion resistance within the TiO2 film could significantly be reduced. The cell conversion efficiency increased from 3.61 to 5.81% under illumination of 100 mW/cm2, an improvement of ca. 55 %. In the fourth part of this thesis (Chapter 6), a series of poly(3,4-alkylenedioxythiophene) counter electrodes prepared by electrochemical polymerization on the fluorine-doped tin oxide (FTO) glass substrate were incorporated in the platinum-free DSSCs. Cells fabricated with a PProDOT-Et2 counter electrode showed a higher conversion efficiency of 7.88 % compared to cells fabricated with PEDOT (3.93 %), PProDOT (7.08 %), and sputtered-Pt (7.77 %) electrodes. The FF was strongly dependent on the deposition charge capacity of the PProDOT-Et2 layer, but the aggregation of PProDOT-Et2 in higher deposition capacities (> 80 mC/cm2) resulted in decreases in JSC and the cell conversion efficiency. Incorporating the best ProDOT-Et2 film (40 mC/cm2) as the counter electrode in plastic DSSC was compared and showed similar tendency as mentioned above. The cell fabricated with a PProDOT-Et2 counter electrode showed a higher conversion efficiency of 5.20 % compared with that fabricated with sputtered-Pt (5.11%) electrodes under the illumination of 100 mW/cm2 (AM 1.5G).