Modifying the Surface Properties of Indium Tin Oxide with Alcohol-Based Monolayers for Use in Organic Electronics

Transparent conductive oxides (TCOs) serve a critical function in many devices, such as organic light-emitting diodes (OLEDs) and organic photovoltaics (OPVs). To optimize the performances of these devices, it is desirable to tune the interface between the TCO and the next functional layer of these devices. Self-assembled monolayers prepared from phosphonic acids and silanes are commonly used to tune the properties and performance of this interface, including its surface energy, work function, and durability. Here, we report a new form of self-assembled monolayers for modifying indium tin oxide (ITO), a standard TCO used in OLEDs and OPVs. The ITO surfaces were modified with a series of distinct alcohol reagents. Stabilities of these alcohol-based monolayers were compared with modifications derived from silanes and phosphonic acids, which are commonly used in the literature and industrial processes. Work functions and surface energies of these modified substrates were determined using ultraviolet photoelectron spectroscopy and contact angle measurements. Stability of these monolayers was assessed using cyclic voltammetry, X-ray photoelectron spectroscopy, and transmission spectroscopy techniques. On the basis of the results of these studies, alcohol-based monolayers are promising candidates to modify ITO substrates for use in OLEDs and OPVs

Investigation of the photocatalytic lithographic deposition of metals in sealed microfluidic devices on TiO2 surfaces

The research presented within this dissertation explores the photocatalytic deposition of metal carried out within sealed microfluidic channels. Micro scale patterning of metals inside sealed microchannels is investigated as well as nanoscale control over the surface morphology of the nanoparticles making up the patterns. This is achieved by controlling solution conditions during deposition. Finally, the nanoparticle patterns are used in fabricating a sensor device, which demonstrates the ability to address multiple patches within a sealed channel with different surface chemistries. Also presented here is the construction of the first epifluorescence/total internal reflection macroscope. Its ability to carry out high numerical aperture imaging of large arrays of solid supported phospholipid bilayers is explored. For this, three experiments are carried out. First, imaging of a 63 element array where every other box contains a different bilayer is preformed, demonstrating the ability to address large scale arrays by hand. Next, a protein binding experiment is preformed using two different arrays of increasing ligand density on the same chip. Finally, a two-dimensional array of mixed fluorescent dyes contained within solid supported lipid bilayers is imaged illustrating the ability of the instrument to acquire fluorescent resonance energy transfer data. Additionally, the design and fabrication of an improved array chip and addressing method is presented. Using this new array chip and addressing method in conjunction with the epifluorescence/total internal reflection macroscope should provide an efficient platform for high throughput screening of important biological processes which occur at the surfaces of cell membranes

SURFACE CHEMISTRY EVALUATION IN THE DESIGN AND FABRICATION OF MICRO-DEVICES FOR PROTEIN ANALYSIS

In this Ph.D. thesis, the problem of the coating and adhesion of polymers onto selected surfaces has been investigated with the aim of designing micro-devices and/or microarrays for protein analysis. In the first part of the thesis, the micro-fabrication of a device for isoelectric focusing has been studied. The development of this device has required the covalent attachment of hydrogel plugs functionalized with pH buffering monomers on an Indium Tin Oxide (ITO) flat surface. The two ITO-coated slides are separated by silicon frames (both 3mm thick) stuck on the surface and the whole device was named as Micro Parallel Isoelectric focusing Device (MPID). The problem of the adhesion of the hydrogel plugs onto the ITO anode under the high vacuum conditions of the MALDI-TOF/TOF analysis has been solved, by properly selecting the percentage of monomers and related polymerization conditions. The MPID fabricated in accord to previous observations did not afford a completely efficient isolectric separation of the model protein mixture (commercial carbonic anhydrase). Furthermore, the proteins were absorbed onto plugs too tightly for a satisfactory, direct analysis by MALDITOF/ TOF of the plugs. At this stage of the Ph.D. program, the MPID project has been abandoned and the second part of the Ph.D. thesis has been directed towards the study of a functional coating onto different surfaces using a polymer that is the result of the co-polymerization of N,N-dimethylacrylamide (DMA), 3- (trimethoxysilyl)-propylmethacrylate (MAPS) and acryloyloxysuccinimide (NAS) [ Copoly (DMANAS- MAPS)]. It has been shown that this copolymer is able to generate thin layer of nanometer size onto inorganic substrates like glass, silicon oxide, or gold, typically used for the development of microarrays or bio-sensors for immunoassays. Applications of silicon and gold surfaces coated by Copoly (DMA-NAS-MAPS) are presented and discussed

Investigations of Structure / Property Interrelationships of Organic Thin Films Using Scanning Probe Microscopy and Nanolithography

Studies of the surface assembly and molecular organization of organic thin films were studied using scanning probe microscopy (SPM) and scanning probe lithography (SPL). Systems of organic thin films such as n-alkanethiols and pyridyl functionalized porphyrins were characterized at the molecular level, and measurements of the conductive properties of polythiophenes containing in-chain cobaltabisdicarbollides were accomplished. Understanding the self-organization and mechanisms of self-assembly of organic molecules provides fundamental insight for structure/property interrelationships. Investigations of the surface assembly of 5,10-diphenyl-15,20-di-pyridin-4-yl-porphyrin (DPP) on Au(111) were done using SPL methods of nanoshaving and nanografting. Automated computer designs were developed for nanofabrication to provide local characterizations of the thickness of DPP films and nanostructures. Nanolithography was accomplished using DPP films as either matrix self-assembled monolayers (SAMs) or as molecules for nanofabrication. Results presented in this dissertation demonstrate that DPP forms compact layers on Au(111), which can be used for inscribing nanopatterns of n-alkanethiols. Arrays of DPP nanopatterns with precise geometries and alignment were fabricated within n-alkanethiols by nanografting, demonstrating nanoscale lithography with pyridyl porphyrins can be accomplished to produce an upright surface orientation on Au(111) mediated by nitrogen-gold chemisorption. Beyond research investigations, the applicability of atomic force microscopy (AFM) and advancements with automated SPL were applied for teaching undergraduate chemistry laboratories to introduce the fundamentals of surface chemistry and molecular manipulation. New classroom activities were developed for the Chemistry 3493 Physical Chemistry laboratory to give students “hands-on” training with AFM. Undergraduates were trained to prepare nanopatterns of n-alkanethiols using software to control the position, force and speed of the AFM tip for nanolithography experiments. The sensitivity and nanoscale resolution of current sensing AFM was applied for studies of the conductive properties of electropolymerized thin films of polythiophenes with cobaltabisdicarbollide moieties. Images acquired with AFM furnished views of the morphology of different polymers prepared on gold surfaces. Surface maps of the conductivity of electropolymerized films were acquired with AFM current images. These studies provide new insight of the effects of the bound cobaltabisdicarbollide moiety and coordinated metal centers for the electronic properties of the resulting conducting materials

Optically Induced Nanostructures

Nanostructuring of materials is a task at the heart of many modern disciplines in mechanical engineering, as well as optics, electronics, and the life sciences. This book includes an introduction to the relevant nonlinear optical processes associated with very short laser pulses for the generation of structures far below the classical optical diffraction limit of about 200 nanometers as well as coverage of state-of-the-art technical and biomedical applications. These applications include silicon and glass wafer processing, production of nanowires, laser transfection and cell reprogramming, optical cleaning, surface treatments of implants, nanowires, 3D nanoprinting, STED lithography, friction modification, and integrated optics. The book highlights also the use of modern femtosecond laser microscopes and nanoscopes as novel nanoprocessing tools

Micro/Nano Structures and Systems

Micro/Nano Structures and Systems: Analysis, Design, Manufacturing, and Reliability is a comprehensive guide that explores the various aspects of micro- and nanostructures and systems. From analysis and design to manufacturing and reliability, this reprint provides a thorough understanding of the latest methods and techniques used in the field. With an emphasis on modern computational and analytical methods and their integration with experimental techniques, this reprint is an invaluable resource for researchers and engineers working in the field of micro- and nanosystems, including micromachines, additive manufacturing at the microscale, micro/nano-electromechanical systems, and more. Written by leading experts in the field, this reprint offers a complete understanding of the physical and mechanical behavior of micro- and nanostructures, making it an essential reference for professionals in this field

A hybrid piezoelectric and electrostatic energy harvester for scavenging arterial pulsations

Implantable and wearable biomedical devices suffer from a limited lifespan of on-board batteries which results in a requirement to change the battery or the device itself causing additional physical discomfort. In order to overcome this, various energy harvesters have been developed. The human body possesses several types of energy available for scavenging through appropriately designed energy harvesting devices, while cardiovascular system in particular represents a constant reliable source of mechanical energy from vibration. Most conventional energy harvesters exploit only a single phenomenon, such piezo- or triboelectricity, thus producing reduced power density. As an improvement, hybridisation of energy harvesters intends to negate this drawback by simultaneously scavenging energy by multiple harvesters. In the present work, the reverse electrowetting on dielectric (REWOD) phenomenon is combined with the piezoelectric effect in a proof-of-concept hybrid harvester for scavenging biomechanical energy from arterial or other type pulsations. A mathematical model of the harvester was developed, and a computational investigation using CFD, and fluid-structure interaction simulations were carried out using the COMSOL Multiphysics software. The effect of the materials of piezoelectric film and geometrical features of the harvester on parameters such as the displacement, the frequency of pulsations and the energy produced were studied. An experimental setup that could imitate the displacements caused from arterial pulsations was designed and the produced electrical energy characteristics were analysed. A comparison between experimental and computational data was carried out and demonstrated a good agreement. Dependencies between geometrical parameters and electrical output were obtained, recommendation on piezoelectric materials and design solutions were provided

Elektrochemické biosenzory a detektory na bázi pevného stříbrného amalgámu pro analýzu v průtokových systémech

In this Ph.D. thesis new possibilities of using amalgam electrodes are presented. First of all, the tubular detector based on silver solid amalgam (TD-AgSA) was designed for determination of reducible compounds in flow systems. It was tested on model solutions of Cd2+ , Zn2+ and 4-nitrophenol in amperometric mode under conditions of flow injection analysis. Results have shown that developed tubular detector is simple and low cost device suitable for detection of reducible compounds with good sensitivity, repeatability and long-term stability (at least 2 years) with possibility to work at potentials up to 2 V in aqueous solutions. Afterwards, this newly developed detector was successfully used for the determination of an active ingredient lomustine in pharmaceutical preparation CeeNU® Lomustine by non-stop-flow differential pulse voltammetry based on reduction of present nitroso group. For measurements in the flow system miniature reference electrodes saturated calomel electrode, mercury-mercurous sulfate, and mercury-mercuric oxide electrode based on paste silver solid amalgam were fabricated and tested for 14 months. The calomel electrode based on paste silver amalgam proved to be the most resistant to polarization and it was used in all experiments in this thesis. Next, the electrochemical...6 Abstrakt Tato disertační práce představuje nové možnosti využití amalgámových elektrod zejména při konstrukci elektrochemických biosenzorů. V první řadě byl navržen a zkonstruován tubulární detektor na bázi stříbrného pevného amalgámu pro stanovení redukujících se analytů v průtokových systémech. Nejdříve byl testován při ampérometrickém stanovení modelových roztoků Cd2+ , Zn2+ a 4-nitrophenolu pomocí injekční průtokové analýzy. Výsledky ukázaly, že navržený tubulární detektor představuje jednoduché a levné zařízení s dobrou opakovatelností, citlivostí a dlouhodobou stabilitou minimálně 2 roky. Jednou z hlavních jeho výhod je možnost měření při vysokých negativních potenciálech (~ 2 V ve vodném prostředí). Poté byl tubulární detektor úspěšně použit pro stanovení účinné látky lomustinu v chemoterapeutickém léčivu CeeNU® Lomustine metodou průtokové diferenční pulsní voltametrie. Pro stanovení v průtokových systémech byly taktéž navrženy a 14 měsíců testovány miniaturní referentní elektrody kalomelová (SCE-AgPA), merkurosulfátová a merkuroxidová na základě stříbrného pastového amalgámu. Všechny referentní elektrody se ukázaly být stabilní po celou dobu zkoumání. Největší odolnost proti polarizaci byla zaregistrována u SCE-AgPA, a proto právě tato referentní elektroda byla použita pro všechny experimenty...Department of Analytical ChemistryKatedra analytické chemiePřírodovědecká fakultaFaculty of Scienc