The research presented in this dissertation focuses on the design and synthesis of novel hybrid conjugated polymer materials using two different approaches: 1) inorganic/organic hybrid semiconductors through the incorporation of carboranes into the polymer structure and 2) the modification of surfaces with conjugated polymers via grafting approaches. Hybrid conjugated polymeric materials, which are materials or systems in which conjugated polymers are chemically integrated with non-traditional structures or surfaces, have the potential to harness useful properties from both components of the material to help overcome hurdles in their practical realization in polymer-based devices. This work is centered around the synthetic challenges of creating new hybrid conjugated systems and their potential for advancing the field of polymer-based electronics through both greater understanding of the behavior of hybrid systems, and access to improved performance and new applications. Chapter 1 highlights the potential applications and advantages for these hybrid systems, and provides some historical perspective, along with relevant background materials, to illustrate the rationale behind this work. >Chapter 2 explores the synthesis of poly(fluorene)s with pendant carborane cages. The Ni(0) dehalogenative polymerization of a dibromofluorene with pendant carborane cages tethered to the bridging 9-position produced hybrid polymers produced polymers which combined the useful emissive characteristics of poly(fluorene) with the thermal and chemical stability of carborane cages. The materials were found to display increased glass transition temperatures and showed improved emission color stability after annealing at high temperatures relative to the non-hybrid polymer. The design and synthesis of a poly(fluorene)-based hybrid material with carborane cages in the backbone, rather than as pendant groups, begins in chapter 3. Poly(fluorene) with p-carborane in the backbone is synthesized and characterized, and the material is found to be a high MW, soluble blue emitter which shows a higher glass transition temperature and greater stability than a non-hybrid polymer. UV absorbance and fluorescence spectroscopy indicated some electronic interaction between the conjugated polymer and the cages, but they did not appear to be fully conjugated in the traditional sense. Chapter 4 describes the design, synthesis, and characterization of poly(fluorene) with o-carborane in the backbone. Profound changes in the behavior of the polymer, from its polymerization behavior to its emission characteristics, were observed and their origins are discussed. Experiments to explore the nature of the cage/polymer interactions were performed and possible applications which take advantage of the unique nature of the o-carborane hybrid polymer are explored and discussed. Hybrid conjugated polymer materials via grafting approaches to surfaces and surface modification are discussed starting in chapter 5. The synthesis of a dibromofluorene-based silane coupling agent for the surface functionalization of oxide surfaces is presented, and the surface directed Ni(0) dehalogenative polymerization of poly(dihexylfluorene) is explored. Chapter 6 focuses on the exploration of conjugated polymer/cellulose hybrid materials. Surface medication of cellulose materials with monomer-like anchor points is discussed. Grafting of the modified cellulose with conjugated polymers was explored and the grafting of three different repeat structures based on fluorene-, fluorenevinylene-, and fluoreneethynylene motifs were optimized to provide a general route to cellulose/conjugated polymer hybrid materials. Characterization and possible applications of such hybrid materials are discussed. Finally, chapter 7 is devoted to the simultaneous surface patterning and functionalization of poly(2-hydroxyethylmethacrylate) thin films using a silane infusion-based wrinkling technique. While not a conjugated polymer system, the spontaneous patterning and functionalization methods explored in this chapter produce hybrid organic/inorganic polymer thin films which have applications that range from optics, to adhesion, to polymer-based electronics, and the research compliments the other chapters. The spontaneous generation of complex patterns, of a small scale approaching 100nm feature size, over a large area with simultaneous control over surface chemistry is explored. Examples of complex, hierarchically patterned films which integrate lithographic processes such as nanoimprint lithography and electron beam lithography with spontaneous patterning via wrinkling are presented.

Heutzutage werden riesige Datenmengen zwischen Endgeräten und Cloud-Servern verschoben. Cloud-Computing war nach Bloomberg bereits für 1% des weltweiten Stromverbrauchs im Jahr 2021 verantwortlich. Darüber hinaus kann die monopolartige Speicherung personenbezogener Daten schwerwiegende Auswirkungen auf die Gesellschaften unserer Welt haben. Um persönlichen Datenschutz und einen nachhaltigen Energieverbrauch zu gewährleisten, bedarf es einer Datenverarbeitung direkt am Endgerät; bezeichnet als Edge Computing. In diesem Zuge wird die Nachfrage nach individuell gestalteten Edge-Geräten rapide ansteigen. Der neu entstehende Markt bietet der organischen elektrochemischen Elektronik eine große Chance, vor allem für bioelektronische Anwendungen; allerdings muss die Chipintegration verbessert werden. In dieser Arbeit habe ich elektrochemische organische Elektronik für die Integration in Computersysteme untersucht. Insbesondere habe ich einen festen, photostrukturierbaren Elektrolyten entwickelt, der die Integration von OECTs ohne Kreuzkommunikation zwischen Bauteilen ermöglicht. Die OECTs arbeiten bei Spannungen unter 1V und schalten mit einem großen An/Aus-Verhältnis von 5 Größenordnungen und einer Unterschwellenschwingung nahe des thermodynamischen Minimums von 60mV/Dekade. Darüber hinaus wurden bei der Untersuchung der Hysterese des Bauelements drei verschiedene Hystereseregime identifiziert. Anschließend untersuchte ich die Schaltdynamik des OECTs und demonstrierte ein Top-Gate-OECT mit einer maximalen Betriebsfrequenz von 1 kHz. Beim Versuch, die komplexe Wechselwirkung zwischen Ionen und Elektronen in integrierten OECTs zu verstehen, habe ich einen grundlegenden elektrochemischen Mechanismus identifiziert. Die Abhängigkeit dieses Mechanismus’ von der Gate-Größe und der Drain-Überlapplänge wurde aufgezeigt und dieses Wissen zur Optimierung elektrochemischer Inverter genutzt. Zur Darstellung von OECT-basierten Schaltungskomponenten habe ich verschiedene Halbleiter verwendet und entsprechende Inverter hergestellt. Schließlich wurde die Hysterese eines einzigen ambipolaren Inverters zur Demonstration eines dynamischen Klinkenschalters genutzt. Im Rahmen dieser Arbeit habe ich die OECT-Technologie von den Anfängen bis hin zu integrierten Schaltkreiskomponenten entwickelt. Ich glaube, dass diese Arbeit ein Startschuss für Wissenschaftler und Ingenieure sein wird, um die OECT-Technologie in der realen Welt des Edge Computing einzusetzen. / Nowadays, vast amounts of data are shuttled between end-user devices and cloud servers. This cloud computing paradigm was, according to Bloomberg, already responsible for 1% of the world’s electricity usage in 2021. Moreover, the monopoly-like storage of personal data can have a severe impact on the world’s societies. To guarantee data privacy and sustainable energy consumption in future, data computation directly at the end-user site is mandatory. This computing paradigm is called edge computing. Owing to the vast amount of end-user-specific applications, the demand for individually designed edge devices will rapidly increase. In this newly approaching market, organic electrochemical electronics offer a great opportunity, especially for bioelectronic applications; however, the integration into low-power-consuming systems has to be improved. In this work, I investigated electrochemical organic electronics for their integration into computational systems. In particular, I developed a solid photopatternable electrolyte that allows integrating organic electrochemical transistors (OECTs) without cross-talk between adjacent devices. The OECTs operate at voltages below 1 V, and exhibit a large on/off ratio of 5 orders of magnitude and a subthreshold-swing close to the thermodynamic minimum of 60mV/dec. Moreover, investigating the device’s hysteresis, three distinct hysteresis regimes were identified; the RC-time-dominated regime I, the retention time governed regime II, and the time-independent stable regime III. I then examined the OECT’s switching dynamics and, subsequently, demonstrated a top-gate device with a maximum operating frequency of 1 kHz. Trying to understand the complex interaction between ions and electrons in integrated OECTs, I disclosed a fundamental electrochemical mechanism and named it the electrochemical electrode coupling (EEC). The EEC’s dependence on gate size and drain overlap length was rigorously shown, and this knowledge was used to optimize electrochemical inverters. Yet, to exemplify OECT-based circuit components, I employed various semiconductors and fabricated five inverters, each with its unique advantage. Finally, the ambipolar inverter’s hysteresis was used to demonstrate a single-device dynamic latch, a basic in-memory computational element. In this thesis, I developed the OECT technology from an infancy stage to integrated circuit components. I believe that this work will be a starting signal for scientists and engineers to bring the OECT technology into real-world edge computing.

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This dissertation will outline solution processable materials and fabrication techniques to manufacture flexible electronic devices from them. Conductive ink formulations and inkjet printing of gold and silver on plastic substrates were examined. Line patterning and mask printing methods were also investigated as a means of selective metal deposition on various flexible substrate materials. These solution-based manufacturing methods provided deposition of silver, gold and copper with a controlled spatial resolution and a very high electrical conductivity. All of these procedures not only reduce fabrication cost but also eliminate the time-consuming production steps to make basic electronic circuit components. Solution processable semiconductor materials and their composite films were also studied in this research. Electrically conductive, ductile, thermally and mechanically stable composite films of polyaniline and sulfonated poly (arylene ether sulfone) were introduced. A simple chemical route was followed to prepare composite films. The electrical conductivity of the films was controlled by changing the weight percent of conductive filler. Temperature dependent DC conductivity studies showed that the Mott three dimensional hopping mechanism can be used to explain the conduction mechanism in composite films. A molecular interaction between polyaniline and sulfonated poly (arylene ether sulfone) has been proven by Fourier Transform Infrared Spectroscopy and thermogravimetric analysis. Inkjet printing and line patterning methods also have been used to fabricate polymer resistors and field effect transistors on flexible substrates from poly-3-4-ethyleneoxythiophene/poly-4-sytrensulfonate. Ethylene glycol treatment enhanced the conductivity of line patterned and inkjet printed polymer thin films about 900 and 350 times, respectively. Polymer field effect transistors showed the characteristics of traditional p-type transistors. Inkjet printing technology provided the transfer of semiconductor polymer on to flexible substrates including paper, with high resolution in just seconds. / Ph. D.

<p dir="ltr">First, we aimed to incorporate stable tetracyanocyclopentadienide (TCCp) aromatic ani­ons into polynorbornene-based electrolytes, emphasizing controlled synthesis and properties through ring-opening metathesis polymerization (ROMP). Here, we first successfully incorporate a stable tetracyanocyclopentadienide (TCCp) aromatic anion into polynorbornene (PNb)-based elec­trolytes (PNb-TCCp) through ring-opening metathesis polymerization (ROMP) with controllable molecular weight and low polydispersity. PNb-TCCp shows a high ionic conductivity of 4.5 × 10^–5 S/cm in thin films. Due to its highly stable aromatic anion groups and favorable interactions with aromatic cations, it could improve thermal stability of doped conjugated polymers. Pairing with doped poly(3,4-ethylenedioxythiophene) (PEDOT) through salt metathesis, the generated poly ion complex PEDOT:PNb-TCCp retains its conductivity up to 180 °C.</p><p dir="ltr">Second, we aim to develop new photocatalysts for O-ATRP. We discovered a novel one-pot synthetic approach elu­cidates the formation of core-extended <i>N,N</i>′-disubstituted diaryl dihydrophenazine diradical dica­tions (DRDCs) via chemical oxidation. These DRDCs were reduced to their neutral state and found to have photocatalytic abilities, expanding the knowledge for O-ATRP photocatalysts.</p><p dir="ltr">Finally, we aim to understand the fundamental structure property relationship of the n-doped n-PBDF. The n-doped poly(benzodifurandione) (<b>n-PBDF</b>) is an n-type conducting polymer with characteristics such as high electrical conductivity, solution processability, and weathering stability. Here, we sys­tematically in­vestigate the structure property relationship on the impact of structural mod­ifications through aromatic substitution on the photophysical, electrical, and structural properties of <b>n-PBDF</b> and its oligomeric derivatives. We demonstrated that an electron donation group (methyl) raised the highest occupied molecular orbital energy level (+0.15 eV), while electron withdrawing halogens (Br and Cl) decreased the lowest unoccupied molecular orbital energy level (−0.12 eV and −0.13 eV, respectively) in the polymers. Additionally, in the both the undoped and doped oligo­meric systems, these substitutions introduce large torsion angles (<i>θ </i>> 17°), causing the material to twist significantly. Moreover, the methyl substituted polymer,<b> n-PBDF-Me</b>, was evaluated for its potential as a transparent organic conductor, due to its high optical transmittance (<i>T</i>₅₅₀> 93%). However, <b>n-PBDF-Me</b> films have significantly lower con­ductiv­ity than <b>n-PBDF</b> (0.40 S/cm vs 1330 S/cm) at similar thickness.</p>

Charged organic species are ubiquitous throughout organic chemistry. They are ideal ascomponents in organic electronics, and are common as transition states or intermediates in many organic transformations. This dissertation details the investigation of the effect of external electric fields on reactions with charged transition states, as well as the incorporation of triarylmethylium and triangulenium cations as components in single-molecule and organic electronics. Chapter 1 provides an introduction to the scanning tunneling microscope break junction (STM-BJ) technique, which is used as a tool to assess the effect of external electric fields on reaction rate and the performance of single-molecule devices. In this chapter, the different design criteria for molecules used in both single-molecule and optoelectronic devices are discussed. Chapter 2 evaluates the effect of electric fields on two classes of reactions with charged transition states – the Menshutkin reaction and the Chapman rearrangement. Chapter 3 describes triarylmethylium and triangulenium dyes as single-molecule devices, and how their conductance can be tuned through different pendant substituents via Fano resonances. Chapter 4 details an ongoing project that incorporates triangulenium cores to yield a modular donor-acceptor system that shows tunable quenching of emission. Finally, Chapter 5 chronicles the progress of our TikTok account called @IvyLeagueScience and outlines the success criteria for using short-form videos as a way of conducting scientific outreach.

This thesis investigates the mechanically controlled break junctions, with a particular emphasis on elucidating the behaviour of molecular currents at room temperature. The core of this experimental investigation involves a detailed analysis of conductance, examining how it varies over time and with changes in the gap between electrodes. Additionally, this study thoroughly evaluates transmission properties, coupling effects, and current characteristics. A pivotal aspect of the research was the meticulous current measurement, followed by carefully selecting optimal data sets. This process set the stage for an in-depth analysis of resonant tunnelling phenomena observed through a single channel. Notably, these experiments were conducted under open atmospheric conditions at room temperature. A significant finding from this study is the recognition that our current model requires refinement. This adjustment is necessary to more accurately encapsulate a broader spectrum of molecular transport mechanisms. Furthermore, this work significantly advances our comprehension of quantum effects in single-molecule junctions, particularly concerning similar molecules to Corannulene extending to some organometallics. One of the essential disclosures is the identification of deviations in the transport model, primarily attributable to electron-electron interactions. This insight is crucial as it paves the way for developing a more comprehensive and precise model, enhancing our understanding of molecular-scale electronic transport.:List of Figures xi List of Tables xiii Acronyms xiii Terminology xv Symbols xvi Abstract xvii 1 Introduction 1 1.1 Motivation and Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.2 Molecular Electronics Background . . . . . . . . . . . . . . . . . . . . . . . . 2 1.3 RelatedWork, the State of Art . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.4 Structure of the work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2 Methods and Implementations 7 2.1 Mechanically Controlled Break Junctions Principle . . . . . . . . . . . . . . 8 2.1.1 Setups forMCBJ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.1.2 Measurement Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . 13 2.1.3 Electrical Diagramof theMeasurement . . . . . . . . . . . . . . . . . 15 2.1.4 Criteria to Select the Data . . . . . . . . . . . . . . . . . . . . . . . . 15 2.2 Experiment Realisation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 3 Molecules and Transport 20 3.1 Molecules in the Scope of this Thesis . . . . . . . . . . . . . . . . . . . . . . 20 3.1.1 Fixation of pi-Conjugated Molecules on Gold Surfaces via Thiol Bond 20 i 3.2 Ballistic Transport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 3.2.1 Tunnelling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 3.3 Single Level Model (SLM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 3.3.1 Chemical Nature of theMolecular Channels . . . . . . . . . . . . . . 24 3.4 TransportMechanisms inMolecules attached toMCBJ . . . . . . . . . . . . 25 4 Results and Discussions 28 4.1 Discussions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 4.1.1 Opening Curves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 4.1.2 HistogramfromtheMeasurements . . . . . . . . . . . . . . . . . . . 30 4.2 Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 4.2.1 Current in Toluene . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 4.2.2 Current in Corannulene . . . . . . . . . . . . . . . . . . . . . . . . . 44 4.2.3 Current in Fe+3 Salen . . . . . . . . . . . . . . . . . . . . . . . . . . 49 4.2.4 Current Measurement after Consecutive Opening - Case Study: Fe+3 Salen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 4.2.5 Single LevelModel - Case Study: Corannulene . . . . . . . . . . . . . 53 4.2.6 Lorentzian Distribution and Fitting in Salen organometallics and Corannulene . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 4.2.7 Single Level Model - Study of the case: Fe+3 Salen . . . . . . . . . . 66 4.3 Transmission and Coupling . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 4.3.1 Transmission and Coupling - Case Study: Fe+3 Salen . . . . . . . . . 70 4.4 Conclusive Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 4.4.1 Hypothesis of Scattering . . . . . . . . . . . . . . . . . . . . . . . . . 76 5 Conclusion and Further Work 78 5.1 The CurrentMeasurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79 5.2 Further Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80 A Current with Mean Normalization i A.1 Categories ofMeasurements . . . . . . . . . . . . . . . . . . . . . . . . . . . ii A.1.1 Measurements without hysteresis or very small . . . . . . . . . . . . . ii A.1.2 Measurements with hysteresis . . . . . . . . . . . . . . . . . . . . . . vi A.2 Measurements without Fitting . . . . . . . . . . . . . . . . . . . . . . . . . . xii B Our best fits where the SLM fails xi