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Study on the doping and dedoping states of poly(3,4-ethylenedioxythiophene): poly(styrenesulphonate).January 2004 (has links)
Luo Yun. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references. / Abstracts in English and Chinese. / Abstract --- p.i / 论文摘要 --- p.ii / Acknowledgements --- p.iii / Table of Contents --- p.iv / List of Figures --- p.vii / List of Tables --- p.xi / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Conjugated Polymers --- p.1 / Chapter 1.1.1 --- Overview --- p.1 / Chapter 1.1.2 --- Conducting Polymers --- p.2 / Chapter 1.2 --- Electrochemical Doping of Conjugated Polymers --- p.5 / Chapter 1.2.1 --- Doping Conjugated Polymers --- p.7 / Chapter 1.2.2 --- Doping Level --- p.8 / Chapter 1.3 --- Charges in Conjugated Polymers --- p.10 / Chapter 1.3.1 --- Electronic and Geometric Configurations --- p.10 / Chapter 1.3.2 --- Charge Carriers --- p.10 / Chapter 1.4 --- Effects of Localization and Structural Disorder on Conductivity --- p.18 / Chapter 1.5 --- Cyclic Voltammetric Behavior of Conjugated Polymers --- p.18 / Chapter 1.6 --- PEDOT: PSS Systems --- p.21 / Chapter 1.7 --- Motivation --- p.25 / References --- p.27 / Chapter Chapter 2 --- Instrumentation --- p.32 / Chapter 2.1 --- X-ray Photoelectron Spectroscopy --- p.32 / Chapter 2.1.1 --- Introduction --- p.32 / Chapter 2.1.2 --- Basic Principles and Theory --- p.32 / Chapter 2.1.3 --- Qualitative Analysis Using XPS --- p.35 / Chapter 2.1.4 --- Angular Effect on XPS --- p.35 / Chapter 2.1.5 --- Chemical Shifts --- p.35 / Chapter 2.1.6 --- Valence Band Investigation --- p.37 / Chapter 2.1.7 --- Quantitative Analysis Using XPS --- p.37 / Chapter 2.1.8 --- Instrumental Setup for XPS --- p.40 / Chapter 2.2 --- Scanning Probe Microscopy --- p.40 / Chapter 2.2.1 --- General Introduction --- p.40 / Chapter 2.2.2 --- Atomic Force Microscopy and Conducting Atomic Force Microscopy --- p.40 / Chapter 2.2.3 --- Instrumental Setup for Conducting AFM --- p.44 / Chapter 2.3 --- Cyclic Voltammetry --- p.44 / Chapter 2.4 --- Kelvin Probe --- p.46 / Chapter 2.5 --- a-step Profilometer --- p.48 / References --- p.49 / Chapter Chapter 3 --- Cyclic Voltammetric Characterization of PEDOT:PSS --- p.51 / Chapter 3.1 --- Film Preparations --- p.51 / Chapter 3.2 --- Electrochemistry --- p.52 / Chapter 3.3 --- Results and Discussions --- p.53 / References --- p.56 / Chapter Chapter 4 --- Electronic Structure of Doped and Dedoped PEDOT:PSS Systems --- p.57 / Chapter 4.1 --- Introduction --- p.57 / Chapter 4.2 --- Sample Preparations --- p.58 / Chapter 4.3 --- Results and Discussions --- p.60 / Chapter 4.3.1 --- XPS of C 1s Core Level of PEDOT:PSS --- p.61 / Chapter 4.3.2 --- XPS of S 2p Core Level of PEDOT:PSS --- p.66 / Chapter 4.3.3 --- XPS of O Is Core Level of PEDOT:PSS --- p.71 / Chapter 4.3.4 --- XPS of Valence Band of PEDOT:PSS --- p.77 / Chapter 4.3.5 --- Further Explanations and Discussions --- p.77 / Chapter 4.4 --- Kevin Probe Measurement --- p.83 / Chapter 4.5 --- Conclusions --- p.83 / References --- p.85 / Chapter Chapter 5 --- Morphology and Nano-scale Electrical Properties of PEDOT:PSS Thin Film --- p.87 / Chapter 5.1 --- Introduction --- p.87 / Chapter 5.2 --- Sample Preparations --- p.87 / Chapter 5.3 --- Results and Discussions --- p.88 / Chapter 5.3.1 --- CAFM on as Prepared PEDOT.PSS and Ar+ Sputtered Thin Film --- p.88 / Chapter 5.3.2 --- CAFM on pH Dedoped PEDOT:PSS (pH=6.6) --- p.95 / Chapter 5.3.3 --- CAFM on Electrochemically Dedoped PEDOTrPSS --- p.98 / Chapter 5.4 --- Conclusions --- p.105 / References --- p.106 / Chapter Chapter 6 --- Concluding Remarks and Future Work --- p.107 / Chapter 6.1 --- Concluding Remarks --- p.107 / Chapter 6.2 --- Future Work --- p.108
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Conducting polymers for neural interfaces: impact of physico-chemical properties on biological performanceGreen, Rylie Adelle, Graduate School of Biomedical Engineering, Faculty of Engineering, UNSW January 2009 (has links)
This research investigates the use of conducting polymer coatings on platinum (Pt) electrodes for use in neuroprostheses. Conducting polymers aim to provide an environment conducive to neurite outgrowth and attachment at the electrode sites, producing intimate contact between neural cells and stimulating electrodes. Conducting polymers were electropolymerised onto model Pt electrodes. Conventional polymers polypyrrole (PPy) and poly-3,4-ethylenedioxythiphene (PEDOT) doped with polystyrenesulfonate (PSS) and para-toluenesulfonate (pTS)were investigated. Improvement of material properties was assessed through the layering of polymers with multi-walled carbon nanotubes (MWNTs). The ability to incorporate cell attachment bioactivity into polymers was examined through the doping of PEDOT with anionic laminin peptides DCDPGYIGSR and DEDEDYFQRYLI. Finally, nerve growth factor (NGF), was entrapped in PEDOT during polymerisation and tested for neurite outgrowth bioactivity against the PC12 cell line. Each polymer modification was assessed for electrical performance over multiple reduction-oxidation cycles, conductivity and impedance spectroscopy, mechanical adherence and hardness, and biological response. Scanning electron microscopy was used to visualise film topography and x-ray photon spectroscopy was employed to examine chemical constitution of the polymers. For application of electrode coatings to neural prostheses, optimal bioactive conducting polymer PEDOT/pTS/NGF was deposited on electrode arrays intended for implantation. PC12s were used to assess the bioactivity of NGF functionalised PEDOT when electrode size was micronised. Flexibility of the design was tested by tailoring PEDOT bioactivity for the cloned retinal ganglion cell, RGC-5, differentiated via staurasporine. It was established that PEDOT films had superior electrical and cell growth characteristics, but only PPy was able to benefit from incorporation of MWNTs. Bioactive polymers were produced through inclusion of both laminin peptides and NGF, but the optimum film constitution was found to be PEDOT doped with pTS with NGF entrapped during electrodeposition. Application of this polymer to an implant device was confirmed through positive neurite outgrowth on vision prosthesis electrode arrays. The design was shown to be flexible when tailored for RGC-5s, with differentiation occurring on both PEDOT/pTS and PEDOT/DEDEDYFQRYLI. Conducting polymers demonstrate the potential to improve electrode-cell interactions. Future work will focus on the effect of electrical stimulation and design of bioactive polymers with improved cell attachment properties.
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A conductor's analysis of Gabriel Fauré's Requiem, Op. 48McKendrick, Ryan P. January 2007 (has links)
Thesis (M. Mu.)--Georgia State University, 2007. / Title from file title page. John B. Haberlen, committee chair; N. Lee Orr, Duncan Couch, committee members. Electronic text (47 p. : music) : digital, PDF file. Description based on contents viewed Dec. 14, 2007. Includes bibliographical references (p. 47).
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Study of Zn1-x-yLixSnyO thin films by growth and physics propertiesYang, Kung-shang 09 September 2010 (has links)
Since the discovery of transparent conducting oxide (TCO) thin films¡ATCO has been widely used in optoelectronic devices. To increase the potential application of the TCO, this study aims at growing amorphous TCO thin films which possess visible transparency and high electric conductivity. Up to date, only IGZO exhibits these properties. However, the nature resource of indium, the main material in IGZO, is rare and expensive. In this study, searching for new materials that do not contain In, while manifest high transparent and conductivity is our major challenge.
ZnO has an energy band gap of 3.4eV, for which visible photon does not have enough energy to excite the electron in ZnO from the valence band to conduction band. Therefore, it reveals itself as transparent. ZnO materials are relative stable in high temperature and chemical environments and thus a good candidate for been developed into amorphous TCO.
The reason for the high conductivity in amorphous IGZO thin films is because the S orbital of In is spherical symmetry and has large radius in which can overlap with the next In ions to form a continuous band for conduction. In this study, a similar strategy is employed by use of the large S orbital of the doping tin (Sn) in ZnO. A ceramic ZnO target for the pulse laser deposition system is partially wrapped with tin foil. The optimum growth condition are searching by tuning oxygen partial pressure, laser energy, the distance between the target and substrate, and substrate temperature.
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Waking angels, a light unto the darkness, and a crescent still abides : the elegiac music of David R. Gillingham /Batcheller, James Christopher, January 2000 (has links)
Thesis (D.M.A.)--University of Oklahoma, 2000. / Includes bibliographical references (leaves 244-249).
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Improving capacitance and cyclability in microbial cellulose based ultracapacitorsYoung, Nathaniel James 17 February 2012 (has links)
Microbial Cellulose (MC) is a highly porous macromolecule
with intrinsic
properties that make it a useful substrate for conductive materials within ultracapacitors.
MC has the potential to increase capacitance by serving as a high surface area substrate
for conductive polymers and carbonaceous materials. Electrode surface area is a critical
parameter in ultracapacitors because capacitance depends on the available active sites
that are accessible to counter ions. Commercial ultracapacitors increase electrode surface
area by adding microsize carbonaceous materials. Most commercial devices also require
adhesive compounds to bind the conductive material to the substrate. Adhesive
compounds increase sheet resistance and hinder overall capacitance. MC membranes
possess highlyordered surface hydroxyl groups that readily bind to different types
conductive materials and reduce the need for additive adhesive compounds. This thesis
investigates three unique methods for converting a MC membrane into a working
ultracapacitor electrode. In the first method, polypyrrole and carbon nanotubes (CNTs) are added to a
medium of Acetobacter that incorporates the material into a homogeneous crystalline
matrix of beta1,4 glucan chains. The resulting MC is a fully integrated membrane with a
homogeneous embedded layer of conductive material. SEM imaging shows the
conductive material is incorporated primarily at the core of the membrane. As a result,
this electrode suffered from high sheet resistance and did not generate any significant
capacitance. In the second method, a conductive ink consisting of CNTs, carboxymethyl
cellulose (CMC), polypyrrole, and DI water was used to coat the surface of a dried
cellulose membrane. After 12 hours, the ink dries and leaves a shiny black conductive
layer on the membrane’s surface. CMC’s role in the ink is to increase viscosity and help
bind the conductive material to the membrane surface. CMC is also a dielectric material
that acts as an insulator to the polypyrrole and CNTs, and ultimately impedes electrical
energy storage. In the final method, a MC membrane was soaked in aqueous and non
aqueous pyrrole solutions, and polymerized with FeCl3 and Fe2(SO4)3. Single and double
membrane device configurations were also investigated. Surface polymerization of
pyrrole monomers proved to be the best method for converting microbial cellulose into a
working electrode with good capacitance and cyclability. / text
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Conducting polymers for n-type semiconductors, molecular actuators, and organic photovoltaicsDinser, Jordan Alyssa 02 December 2013 (has links)
The majority of conjugated polymers are more stable as p-doped materials than n-doped materials. Stable n-doped polymers are still desirable and for all polymer OPVs, pLEDS, n-channel FETs, and other polymeric electronic devices. The use of donor-acceptor architectures has led to improvements in n-type polymer performance. The approach taken here has been to include a metal-coordination site within a donor-acceptor polymer backbone in order to explore the effect of redox matching between the conjugated polymer backbone and the transition metal center.
Conducting polymers have shown promise as polymeric actuators for prosthetics, robotics, and dynamic braille displays. For the majority of conducting polymers, the actuation mechanism is a bulk phenomenon related to the uptake and expulsion of counterions. This performance may be improved by incorporating monomers which display geometry changes as a function of oxidation state into the polymer backbone. The molecular-level actuation should additively yield a macroscopic actuation that would surpass as well as compliment the bulk mechanism discussed above. We have synthesized a conjugated polymer which incorporates the sym-dibenzocyclooctatetraene moiety, which is known to undergo a change in geometry from a tub-shaped neutral structure to a planar radical anion, into the polymer backbone.
The solution processability of conjugated polymers promises large-scale roll-to-roll processing for organic photovoltaics. However, the use of thin active layers in the majority of high efficiency devices reported to date prohibits this. The recently reported donor-acceptor copolymer KP115 shows high efficiencies in polymer-fullerene blend bulk heterojunction devices even with very thick active layers. This has been reported to be unrelated to the morphology of the blends. By further characterizing this material and preparing derivatives of this polymer, we aim to relate the unique performance of these devices to a structural feature of the polymer. It is proposed that the low recombination rates observed for these blends may be due to the presence of discrete donor and acceptor units in the polymer backbone. In order to further explore this idea, we have a prepared a derivative of KP115 in which a conjugation-breaking meta-phenyl linkage has been introduced between the silolodithiophene unit and the dithienylthiazolo[5,4-d]thiazole unit. / text
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Alkyl substituted polythiophenesMiddlecoff, Jennifer Simmons 05 1900 (has links)
No description available.
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Nondestructive characterization of polyaniline emeraldine base filmsOu, Runqing 08 1900 (has links)
No description available.
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Magnetic instability, magnetoconvection and magnetic field generation in a plane layerTucker, Philip John Yorke January 1998 (has links)
No description available.
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