A novel localized surface plasmon resonance (LSPR) sensor that differentiates between background refractive index changes and surface-binding of a target analyte (e.g. a target molecule, protein, or bacterium) is presented. Standard, single channel LSPR sensors cannot differentiate these two effects as their design allows only one mode to be coupled. This novel technique uses two surface plasmon modes to simultaneously measure surface binding and solution refractive index changes. This increases the sensitivity of the sensor. Different channels or modes can be created in sensors with the introduction of gold nanospheres or gold nanorods that act as receptor mechanisms. Once immobilization was achieved on gold nanospheres, the technique was optimized to achieve the same immobilization for gold nanorods to get the expected dual mode spectrum. Intricate fabrication methods are illustrated with using chemically terminated self assembled monolayers. Then the fabrication process advances from chemically silanized nanoparticles, on to specific and systematic patterns generated with the use of Electron Beam Lithography. Comparisons are made within the different methods used, and guidelines are set to create possible room for improvement. Some methods implemented failed, but there was a lot to learn from these unsuccessful outcomes. Finally, the applications of the dual mode sensor are introduced, and current venues where the sensors can be used in chemical and biological settings are discussed.

A novel cyclopentadienylruthenium(II) thiolato Schiff base,[Ru(SC6H4NC(H)C6H4OCH2CH2SMe)(η5-C2H5]2 was synthesized and deposited as a selfassembled monolayer (SAM) on a gold electrode. Effective electronic communication between the Ru(II) centers and the gold electrode was established by electrostatically cycling the Shiff base-doped gold electrode in 0.1 M NaOH from -200 mV to +600 mV. The SAMmodified gold electrode (Au/SAM) exhibited quasi-reversible electrochemistry. The integrity of this electro-catalytic SAM, with respect to its ability to block and electro-catalyze certain Faradaic processes, was interrogated using Cyclic and Osteryoung Square Wave voltammetric experiments. The formal potential, E0', varied with pH to give a slope of about - 34 mV pH-1. The surface concentration, Γ, of the ruthenium redox centers was found to be 1.591 x 10-11 mol cm-2. By electrostatically doping the Au/SAM/Horseradish peroxidase at an applied potential of +700 mV vs Ag/AgCl, a biosensor was produced for the amperometric analysis of hydrogen peroxide, cumene hydroperoxide and tert-butylhydroperoxide. The electrocatalytic-type biosensors displayed typical Michaelis-Menten kinetics with their limits of detection of 6.45 μM, 6.92 μM and 7.01 μM for hydrogen peroxide, cumene hydroperoxide and tert-butylhydroperoxide respectively / Magister Scientiae - MSc

Electrically conductive adhesives (ECAs) are one of the lead-free interconnect materials with the advantages of environmental friendliness, mild processing conditions, fewer processing steps, low stress on the substrates, and fine pitch interconnect capability. However, some challenging issues still exist for the currently available ECAs, including lower electrical conductivity, conductivity fatigue in reliability tests, limited current-carrying capability, poor impact strength, etc. The interfacial properties is one of the major considerations when resolving these challenges and developing high performance conductive adhesives. Surface functionalization and interface modification are the major approaches used in this thesis. Fundamental understanding and analysis of the interaction between various types of interface modifiers and ECA materials and substrates are the key for the development of high performance ECA for lead-free interconnects. The results of this thesis provide the guideline for the enhancement of interfacial properties of metal-metal and metal-polymer interactions. Systematic investigation of various types of ECAs contributes to a better understanding of materials requirements for different applications, such as surface mount technology (SMT), flip chip applications, flat panel display modules with high resolution, etc. Improvement of the electrical, thermal and reliability of different ECAs make them a potentially ideal candidate for high power and fine pitch microelectronics packaging option.

PhD / SYNOPSIS OF THIS THESIS The aim of this thesis is to more fully understand and explain the binding mechanism of organic molecules to the Au(111) surface and to explore the conduction of such molecules. It consists of five discreet chapters connected to each other by the central theme of “The Single Molecule Device: Conductance and Binding”. There is a deliberate concentration on azine linkers, in particular those with a 1,10-phenanthroline-type bidentate configuration at each end. This linker unit is called a “molecular alligator clip” and is investigated as an alternative to the thiol linker unit more commonly used. Chapter 1 places the work in the broad context of Molecular Electronics and establishes the need for this research. In Chapter 2 the multiple break-junction technique (using a Scanning Tunnelling Microscope or similar device) was used to investigate the conductance of various molecules with azine linkers. A major finding of those experiments is that solvent interactions are a key factor in the conductance signal of particular molecules. Some solvents interfere with the molecule’s interaction with and attachment to the gold electrodes. One indicator of the degree of this interference is the extent of the enhancement or otherwise of the gold quantized conduction peak at 1.0 G0. Below 1.0 G0 a broad range for which the molecule enhances conduction indicates that solvent interactions contribute to a variety of structures which could bridge the electrodes, each with their own specific conductance value. The use of histograms with a Log10 scale for conductance proved useful for observing broad range features. vi Another factor which affects the conductance signal is the geometric alignment of the molecule (or the molecule-solvent structure) to the gold electrode, and the molecular alignment is explored in Chapters 3 for 1,10-phenanthroline (PHEN) and Chapter 4 for thiols. In Chapter 3 STM images, electrochemistry, and Density Functional Theory (DFT) are used to determine 1,10-phenanthroline (PHEN) structures on the Au(111) surface. It is established that PHEN binds in two modes, a physisorbed state and a chemisorbed state. The chemisorbed state is more stable and involves the extraction of gold from the bulk to form adatom-PHEN entities which are highly mobile on the gold surface. Surface pitting is viewed as evidential of the formation of the adatom-molecule entities. DFT calculations in this chapter were performed by Ante Bilic and Jeffery Reimers. The conclusions to Chapter 3 implicate the adatom as a binding mode of thiols to gold and this is explored in Chapter 4 by a timely review of nascent research in the field. The adatom motif is identified as the major binding structure for thiol terminated molecules to gold, using the explanation of surface pitting in Chapter 3 as major evidence and substantiated by emergent literature, both experimental and theoretical. Furthermore, the effect of this binding mode on conductance is explored and structures relevant to the break-junction experiment of Chapter 2 are identified and their conductance values compared. Finally, as a result of researching extensive reports of molecular conductance values, and having attempted the same, a simple method for predicting the conductance of single molecules is presented based upon the tunneling conductance formula.

Magister Scientiae - MSc / A novel cyclopentadienylruthenium(II) thiolato Schiff base, [Ru(SC6H4NC(H)C6H4OCH2CH2SMe)(η5-C2H5]2 was synthesized and deposited as a selfassembled monolayer (SAM) on a gold electrode. Effective electronic communication between the Ru(II) centers and the gold electrode was established by electrostatically cycling the Shiff base-doped gold electrode in 0.1 M NaOH from -200 mV to +600 mV. The SAMmodified gold electrode (Au/SAM) exhibited quasi-reversible electrochemistry. The integrity of this electro-catalytic SAM, with respect to its ability to block and electro-catalyze certain Faradaic processes, was interrogated using Cyclic and Osteryoung Square Wave voltammetric experiments. The formal potential, E0', varied with pH to give a slope of about - 34 mV pH-1. The surface concentration, Γ, of the ruthenium redox centers was found to be 1.591 x 10-11 mol cm-2. By electrostatically doping the Au/SAM/Horseradish peroxidase at an applied potential of +700 mV vs Ag/AgCl, a biosensor was produced for the amperometric analysis of hydrogen peroxide, cumene hydroperoxide and tert-butylhydroperoxide. The electrocatalytic-type biosensors displayed typical Michaelis-Menten kinetics with their limits of detection of 6.45 M, 6.92 M and 7.01 M for hydrogen peroxide, cumene hydroperoxide and tert-butylhydroperoxide respectively. / South Africa

Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第14572号 / 工博第3040号 / 新制||工||1453(附属図書館) / 26924 / UT51-2009-D284 / 京都大学大学院工学研究科材料工学専攻 / (主査)教授 杉村 博之, 教授 酒井 明, 准教授 山田 啓文 / 学位規則第4条第1項該当

Ce travail a pour objectif l’élaboration de surfaces permettant le contrôle de l’adsorption protéique et de l’adhésion cellulaire. Deux axes d’études permettent de répondre à cette problématique : d’une part l’optimisation des conditions de greffage par réaction thiol-ène de chaînes éthylène glycol (OEG ou PEG) comportant une fonction thiol sur une monocouche auto-assemblée de trichlorosilane d’undécényle, d’autre part la caractérisation chimique de surface (mesures d’angle de contact, ellipsométrie, microscopie de fluorescence, infrarouge en réflexion totale atténuée IR-ATR, spectroscopie de photoélectrons induits par rayons X XPS, spectrométrie de masse d’ions secondaires à temps de vol ToF-SIMS) à l’issue de chaque étape de traitement. L’étude méthodologique des conditions de greffage thiol-ène montre la mise au point d’un système bicouche structuré après 1 minute de réaction pour le greffage OEG, 1 heure pour le greffage PEG. Par l’emploi de divers substrats (oxyde de silicium, titane, verre), différentes molécules OEG-thiol ou PEG-thiol (longues de 7 à 220 unités éthyléniques, terminées –méthyle, -carboxyle ou –amine), nous mettons en avant les déclinaisons possibles de cette stratégie. Ces terminaisons chimiques conduisent, au choix, à l’inhibition de l’adsorption protéique ou à l’adsorption de biomolécules, albumine de sérum bovin (BSA) ou fibronectine (Fn), permettant de faire de l’adhésion spécifique. Le contrôle, dans le plan de l’échantillon, des zones exposées à la lumière par photochimie lors du greffage thiol-ène autorise le photopatterning des surfaces permettant la maîtrise de l’adsorption protéique et également de l’adhésion cellulaire à la surface. / The aim of this work is to design surfaces allowing controlling cellular adhesion by the study of protein adsorption and cell adhesion. Two main parts were investigated in order to answer this challenge: on one side the optimization of grafting conditions using the thiol-ene reaction of thiol-terminated ethylene glycol chains (OEG or PEG) on a undecenyltrichlorosilane self-assembled monolayer, on the other side the surface chemical characterization (angle contact measurement, ellipsometry, fluorescence microscopy, attenuated total reflection infrared IR-ATR, X-ray Photoelectron Spectroscopy XPS, Time-of-Flight Secondary Ion Mass Spectrometry ToF-SIMS) after each reaction step. The methodological investigation of thiol-ene grafting conditions exhibits the development of a bilayer structured system after a 1 minute reaction time concerning OEG grafting, 1 hour in case of PEG grafting. By using different substrates (silicon oxide, titanium, glass), different molecules OEG-thiol or PEG-thiol (from 7 to 220 ethylene unit long, methyl-, carboxyl- or amine-terminated), we highlight the range of available versions of this strategy. These chemical extremities lead on demand either to protein adsorption inhibition or to biomolecule adsorption, bovine serum albumin (BSA) or fibronectin (Fn) giving access to specific adhesion.By controlling the light-exposed areas in the sample plan, the photochemistry occurring during the thiol-ene grafting allows to design surface patterning for addressing both protein adsorption and cell adhesion on the sample surface.

Abstract This thesis presents a novel method for fabricating quantum dot light-emitting devices (QDLEDs) based on colloidal inorganic light-emitting nanoparticles incorporated into an organic semiconductor matrix. CdSe core/ZnS shell nanoparticles were inkjet-printed in air and sandwiched between organic hole and electron transport layers to produce efficient photon-emissive media. The light-emitting devices fabricated here were tested as individual devices and integrated into a display setting, thus endorsing the capability of this method as a manufacturing approach for full-colour high-definition displays. By choosing inkjet printing as a deposition method for quantum dots, several problems currently inevitable with alternative methods are addressed. First, inkjet printing promises simple patterning due to its drop-on-demand concept, thus overruling a need for complicated and laborious patterning methods. Secondly, manufacturing costs can be reduced significantly by introducing this prudent fabrication step for very expensive nanoparticles. Since there are no prior demonstrations of inkjet printing of electroluminescent quantum dot devices in the literature, this work dives into the basics of inkjet printing of low-viscosity, relatively highly volatile quantum dot inks: piezo driver requirements, jetting parameters, fluid dynamics in the cartridge and on the surface, nanoparticle assembly in a wet droplet and packing of dots on the surface are main concerns in the experimental part. Device performance is likewise discussed and plays an important role in this thesis. Several compositional QDLED structures are described. In addition, different pixel geometries are discussed. The last part of this dissertation deals with the principles of QDLED displays and their basic components: RGB pixels and organic thin-film transistor (OTFT) drivers. Work related to transistors is intertwined with QDLED work; ideas for surface treatments that enhance nanoparticle packing are carried over from self-assembled monolayer (SAM) studies in the OTFT field. Moreover, all the work done in this thesis project was consolidated by one method, atomic force microscopy (AFM), which is discussed throughout the entire thesis.

Philosophiae Doctor - PhD / In this work, DNA aptamer biosensor systems were developed for the detection of l7p-estradiol - an estrogeneous endocrine disrupting chemical (EDC). Endocrine disrupting chemicals are group of compounds that impact negatively on the endocrine system of humans and wildlife. High concentrations of l7p-estradiol in water or food chain disrupts the physiology of the endocrine system of various animal species, leading to feminisation in fish and stimulates the proliferation of cancer cells in humans. Aptasensor systems for the determination of l7pestradiol were prepared with three immobilization platforms: (i) poly(3,4- ethylenedioxythiophene) {PEDOT} doped with gold nanoparticles (AuNPs) to form PEDOTIAuNPs polymeric nanocomposite, (ii) generation 1 poly(propylene thiophenoimine)-copoly( 3 ,4-ethy lenedioxythiophene) dendritic star copolymer (G 1PPT -co-PEDOT), and (iii) generation 2 poly (propylene thiophenoimine)-co-poly(3,4-ethylenedioxythiophene) dendritic star copolymer (G2PPT-co-PEDOT). The morphological properties of the sensor platforms were interrogated by scanning emission microscopy (SEM) and atomic force microscopy (AFM), while their spectroscopic characteristics were studied by Fourier transform infra red spectroscopy (FTIR) and fluorescence spectroscopy. The electrochemical behaviour of the platforms and the aptasensors were studied by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and square wave voltammetry (SWV). The DNA aptamer developed for detecting 17~-estradiol and which was used in the fabrication of all aptamer biosensors in this study is a 76-mer biotinylated aptamer (5'-BiotinGCTTCCAGCTTATTGAATTACACGCAGAGG TAGCGGCTCTGCGCATTCAATGCTGCGCGCTGAAGCGCGGAAGC-3'). AulPEDOTIAuNPslAptamer (platform 1) was obtained by covalently attaching streptavidin to the polymeric nanocomposite platform using carbodiimide chemistry and the aptamer immobilized via streptavidin-biotin interaction. The electrochemical signal generated from the aptamer-target molecule interaction was monitored electrochemically using cyclic voltammetry and square wave voltammetry in the presence of [Fe(CN)6J 3-/4- as a redox probe. The signal current observed was inversely proportional to the concentration of 17Bestradiol. The aptasensor demonstrated specificity toward 17~-estradiol. The detectable concentration range of the 17B estradiol was 0.01 nM-O .09 nM with a detection limit of 3.2 pM. The 76-mer biotinylated aptamer for 17~-estradiol was incorporated into a generation 1 poly(propylenethiophenoimine )-co-poly(3 ,4-ethylenedioxythiophene) dendritic star copolymer modified Au electrode via biotin-avidin interaction (platform 2). The Bode plot shows that the charge transfer dynamics of the nanoelectrode can be frequency modulated while the AulG 1PPTco- PEDOT nanoelectrode exhibited greater semi-conductor behavior (higher phase angle value) than AulG 1PPT due to the incorporation of charged functionalized dendrimer at low frequencies (100 mHz). The biosensor response to 17~-estradiol was based on the decrease in the SWV current as the EDC binds to the ssDNA aptamer on the biosensor. The dynamic linear range of the sensor was 0.01-0.07 nM with a detection limit of7.27 pM. Synthesis of electro synthetic generation G2PPT-co-PEDOT (platform 3) was performed by copolymerization of PEDOT with G2PPT dendrimer modified electrode immersed in a solution of 0.1 M LiCI04 containing 0.1 M EDOT monomer and 0.1 M sodium dodecyl sulphate (SDS) for ten (10) cycles. The electrochemical behaviour of the dendritic star copolymer was investigated with CV and EIS in LiCI04 and phosphate buffer solutions. The results show that the electrochemical deposition of G2PPT-co-PEDOT on gold electrode decreased the electrochemical charge transfer resistance when compared to AuiPEDOTILiCI04 and AuiLiCI04 interfaces. Bode impedimetric analysis indicates that G2PPT-co-PEDOT is a semiconductor. The fabrication of two novel aptasensors (based on platforms 2 and 3) simultaneously on a screen printed micro array electrode of 96-well multichannel electrochemical robotic sensor testing system for the detection of endocrine disrupting l7~-estradiol, was also carried out. The aptasensors responses to l7~-estradiol, based on the decrease in the SWV current, were evaluated.

Die Oberflächeneigenschaften eines Festkörpers können mit Hilfe dünner, durch Selbstorganisation gebildeter Molekülschichten aus Alkoxysilan-Molekülen gezielt verändert werden. Mikrostrukturierte selbstangeordnete Monolagen (SAM) können für die Anwendung in Bauelementen aus organischen Halbleitern von großem Interesse sein. Mikrokontaktdruck und Photolithographie sind zwei etablierte Verfahren, die jedoch Vorlagen und Masken zur Strukturierung benötigen. Dadurch entstehen bei häufig wechselnden Strukturen nicht zu vernachlässigende Rüstzeiten und Kosten. In der vorliegenden Arbeit wird die Erzeugung lateral strukturierter Schichten von Octadecyltrichlorsilan (OTS) auf Siliziumoxidoberflächen am konkreten Beispiel zweier alternativer, sowohl maskenloser als auch kontaktloser Methoden demonstriert: (i) Tintenstrahlverfahren als rein additive Strukturierung, und (ii) laserinduzierte, photothermische Desorption als subtraktive Strukturierung einer OTS-SAM . Für das Tintenstrahldruckverfahren wird an einem Kontaktwinkelmessgerät eine Methode zur Beobachtung und Auswertung der Tropfenverdampfung implementiert und ein Modell für kleine Tropfen entwickelt. Für die subtraktive Strukturierung werden an einem selbst entwickelten Versuchsaufbau die leistungs- und geschwindigkeitsabhängige Strukturbreite untersucht. Die Ergebnisse der beiden Technologieansätze werden verglichen. / With help of thin layers of alkoxysilane molecules formed by self-assembly, the surface properties of solids can be controlled. Microstructured self-assembled monolayers (SAMs) are interesting for applications in components based on organic semiconductors. Two established technologies for the structuring of molecular monolayers are microcontact printing and photolithography, for which templates and masks need to be structured. In this way, setting times and costs are high if variable patterns have to be structured. In this work, the fabrication of laterally structured monolayers from octadecyltrichlorosilane (OTS) is demonstrated for two examples of alternative, both template-free and maskless technologies: (i) inkjet as a purely additive method, and (ii) photothermal laser desorption as a subtractive structuring of an OTS-SAM. For the inkjet technology, a method for the observation and analysis of the evaporation of a droplet is implemented at a goniometer and a mathematical model for small inkjet droplets is extrapolated, For the subtractive laser structuring, the achievable patterning resolution is investigated as a function of laser intensity and scanning speed. The results of both technological approaches are compared.