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abstract: In order to meet climate targets, the solar photovoltaic industry must increase photovoltaic (PV) deployment and cost competitiveness over its business-as-usual trajectory. This requires more efficient PV modules that use less expensive materials, and longer operational lifetime. The work presented here approaches this challenge with a novel metallization method for solar PV and electronic devices. This document outlines work completed to this end. Chapter 1 introduces the areas for cost reductions and improvements in efficiency to drive down the cost per watt of solar modules. Next, in Chapter 2, conventional and advanced metallization methods are reviewed, and our proposed solution of dispense printed reactive inks is introduced. Chapter 3 details a proof of concept study for reactive silver ink as front metallization for solar cells. Furthermore, Chapter 3 details characterization of the optical and electrical properties of reactive silver ink metallization, which is important to understanding the origins of problems related to metallization, enabling approaches to minimize power losses in full devices. Chapter 4 describes adhesion and specific contact resistance of reactive ink metallizations on silicon heterojunction solar cells. Chapter 5 compares performance of silicon heterojunction solar cells with front grids formed from reactive ink metallization and conventional, commercially available metallization. Performance and degradation throughout 1000 h of accelerated environmental exposure are described before detailing an isolated corrosion experiment for different silver-based metallizations. Finally, Chapter 6 summarizes the main contributions of this work. The major goal of this project is to evaluate potential of a new metallization technique –high-precision dispense printing of reactive inks–to become a high efficiency replacement for solar cell metallization through optical and electrical characterization, evaluation of durability and reliability, and commercialization research. Although this work primarily describes the application of reactive silver inks as front-metallization for silicon heterojunction solar cells, the work presented here provides a framework for evaluation of reactive inks as metallization for various solar cell architectures and electronic devices. / Dissertation/Thesis / Doctoral Dissertation Materials Science and Engineering 2019

Following several reports in the past few years about compositional changes on palladium used as a cathode in heavy water electrolysis, the purpose of this research project was to reproduce this results. Two experiments were performed using two cells connected in series, an experimental cell and a control cell. Both experiments used platinum anodes, the experimental cell had a palladium cathode and the control cell had a platinum cathode. The electrolyte was D20 with H2S04. Radiation was monitored during both experiments. Also temperature and voltage were recorded for both experiments, to allow statements about excess heat of the experimental cell in comparison to the control cell. Both experiments had problems with unequal electrolyte loss, so that no statements about excess heat could be made. No significant radiation was detected in either experiment. Also no compositional changes on the palladium cathodes after electrolysis in both experiments could be detected. Impurities in grain-shaped defects on the palladium cathode before the experiment were found in either experiment. These impurities were Si, Ca, 0, and sometimes also Mg, Na and Fe. Localized findings of Au and Pt, in a distance of 1-2μm to each other, were made on the palladium cathode from the second experiment before electrolysis. Spot, grain-shaped and longitudinal defects were found on the original palladium foil used for the cathodes in either experiment No evidence for fusion, or any other nuclear reaction in the crystal lattice of palladium, used as cathode in heavy water electrolysis, was observed.

The aim of this project is to develop strategies for fabrication of carbon electrode surfaces with a view to creating stable and versatile monolayer systems for sensing and other applications. Glassy carbon (GC) electrodes have been successfully modified with versatile monolayers via the electrochemical reduction of aryl diazonium salts. The surfaces modified with diazonium salt monolayers were properly characterised by electrochemistry, AFM and XPS. The rates of heterogeneous electron transfer through organic monolayers on GC, Pyrolysed Photoresist Films (PPF) and gold surfaces have been studied using ferrocene as the redox probe. The diazonium salt monolayers created on GC surfaces demonstrated very stable ability and can serve as a good alternative to alkanethiol selfassembled monolayers on gold electrodes for sensing purposes. Tripeptide Gly-Gly-His modified GC electrodes have been successfully used as the electrochemical copper sensors and were found to be extremely stable. PPF has proved to be a good alternative to the GC electrode for the commercialisation of the fabricated electrochemical sensors. The most important and difficult task of this project is to fabricate glucose biosensors and immunosensors on carbon electrodes. The rigid and conjugated molecular wires (MW) as the efficient conduit for electron transfer, and a molecule with poly(ethylene glycol) chains (PEG) as an insulator for reducing the non-specific protein adsorption were successfully synthesised and introduced in the sensing systems. MW modified on GC electrodes can be used to explore the deeply buried active site of glucose oxidase to achieve direct electron transfer of GOx from the active centre FAD through the MW to the underlying GC electrode, and to fabricate third generation biosensors. The interface comprising mixed monolayers of MW and PEG has the ability to facilitate efficient electron transfer. A label-free immunosensor system has been successfully developed for electrochemical detection of biomolecular pairs such as biotin/antibiotin with low detection limitation based on mixed monolayers of MW and PEG modified GC electrode surfaces. In addition, a displacement assay has shown that the free biotin can compete with the attached biotin for binding antibiotin. SWNTs can be used as an alternative to MW to fabricate another label-free immunosensor system due to the high efficiency of electron transfer that SWNTs have demonstrated.

In the global search for renewable sources of energy, hydrogen is a promising candidate in transportation and electronic applications. Carbon nanotubes (CNTs) have the largest hydrogen storage capacity among the hydrogen storage materials known at present. The Ni-MH battery can be used to store and then discharge large amounts of hydrogen reversibly by using hydrogen storage materials as negative electrode. The electrochemical hydrogen storage performances of metal hydride electrodes with different levels of multi wall carbon nanotubes (20%, 15%, 10%, 5% and 2% of Ni-MH battery's active materials) has been investigated under similar charge-discharge conditions. Electrochemical test cell consisted of a single hydrogen storage negative electrode sandwiched between two NiOOH/Ni(OH)2 positive electrodes. A 6M aqueous KOH solution was used as electrolyte. Electrochemical properties such as specific discharge capacity, high rate charge-discharge capability and cycle life stability have been investigated. The morphology and structure of negative electrode material were examined by scanning electron microscopy, transmission electron microscopy and X-ray diffraction analysis. Chemical analysis of the hydrogen storage alloy was performed using electron probe microanalysis, electron diffraction spectroscopy and induced coupled plasma spectroscopy analysis. Hydrogen absorption-desorption properties were measured in terms of pressure-composition-isotherm curves. It has been found in this study that the presences of CNTs significantly enhanced the overall electrochemical properties of the Ni-MH battery. Maximum specific discharge capacity was observed for 5% CNTs electrode reaching 243 mAh/g, whereas 0% CNTs could only reach 229 mAh/g. High rate charge and discharge capabilities of 5% CNTs electrodes were ~ 241% and 250% higher than the corresponding values for 0% CNTs electrode. Furthermore, the differences in electrochemical hydrogen storage of CNTs with different diameters of 10-20 nm, 20-40 nm, 40-60 nm, and 60-100 nm were investigated. Electrochemical results demonstrated that CNTs with different diameters showed a large variation in the electrochemical hydrogen storage capability under the similar experimental condition. A comparison between electrodes with different CNTs studies was carried out in order to optimize nanotubes choices for Ni-MH battery. It was found that smaller tube diameters, 20-40 nm and 5% CNTs negative electrode showed the best electrochemical properties of Ni-MH battery system.

Consists mainly of offprints of articles by the author / Includes bibliographies / 1 v. (various pagings) : / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (D. Sc.)--University of Adelaide, Faculty of Science, 1985

<p>In this work a modified polyol method was developed to synthesize in-house catalysts. The method was modified for maximum delivery of product and proved to be quick and efficient as well as cost effective. The series of IH catalysts were characterized using techniques such as UV-vis and FT-IR spectroscopy, TEM, XRD, ICP and CV.</p>

Carbon materials are commonly studied as the electrode material for electrochemical double layer capacitance (EDLC) due to their high surface area. The present work aimed to leverage both EDLC and pseudocapacitance through chemical modification of multi-wall carbon nanotubes (MWCNTs) and onion-like carbon (OLC) with polyoxometalates (POMs) to further enhance the performance of these electrodes. Layer-by-layer (LbL) deposition of two commercially available POMs (PMo12O403- and SiMo12O404-) and three synthesized POMs (PMo11VO404-, PMo10V2O405- and PMo9V3O406-) has been investigated. A single-layer of POMs increased the area specific capacitance by approximately three-times, while superimposing of these POMs into two-layer coatings increased the capacitance by approximately five-times. The morphology and composition of these composite materials were investigated using Scanning Electron Microscopy (SEM) and X-ray Photoelectron Spectroscopy (XPS).

Carbon materials are commonly studied as the electrode material for electrochemical double layer capacitance (EDLC) due to their high surface area. The present work aimed to leverage both EDLC and pseudocapacitance through chemical modification of multi-wall carbon nanotubes (MWCNTs) and onion-like carbon (OLC) with polyoxometalates (POMs) to further enhance the performance of these electrodes. Layer-by-layer (LbL) deposition of two commercially available POMs (PMo12O403- and SiMo12O404-) and three synthesized POMs (PMo11VO404-, PMo10V2O405- and PMo9V3O406-) has been investigated. A single-layer of POMs increased the area specific capacitance by approximately three-times, while superimposing of these POMs into two-layer coatings increased the capacitance by approximately five-times. The morphology and composition of these composite materials were investigated using Scanning Electron Microscopy (SEM) and X-ray Photoelectron Spectroscopy (XPS).

Silver nanowire transparent electrodes have recently received much attention as a replacement for indium tin oxide (ITO) for use in various electronic devices such as touch panels, organic solar cells, and displays. The fabrication of silver nanowire electrodes on glass substrates with a sheet resistance as low as 9 Ω/□ and 90% optical transparency at 550 nm is demonstrated. These resistance and transparency values match that of commercially available indium tin oxide and are superior to other alternatives such as carbon nanotube electrodes. The nanowire electrodes are low cost and easy to fabricate. Moreover, by depositing nanowire films on plastic substrates, mechanically flexible electrodes are obtained. The silver nanowire electrodes are integrated into several electronic devices: transparent heaters, organic solar cells, and switchable privacy glass. The concerns about the suitability of silver nanowire electrodes for use in commercial electronic devices are discussed. High surface roughness, one of the major concerns, is addressed by introducing a new method of embedding silver nanowires in a soft polymer. The instability of silver nanowire electrodes under current flow is also demonstrated for the first time. It is shown that silver nanowire electrodes fail under current flow after ass little as 2 days. This failure is caused by Joule heating which causes the nanowires to break up and thus create an electrical discontinuity in the nanowire film. Suggestions for improving the longevity of the electrodes are given.