Ferroelectric materials are known and valued for their multifunctionality arising from the possibility to perturb the remnant ferroelectric polarization by electric field, temperature and/or mechanical stimuli. While inorganic ferroelectrics dominate the current market, their organic counterparts may provide highly desired properties like eco-friendliness, easy processability and flexibility, concomitantly opening unique opportunities to combine multiple functionalities into a single compound that facilitates unprecedented device concepts and designs. Supramolecular organic ferroelectrics of columnar discotic type, that are the topic of this thesis, offer additional advantages related to their strong hierarchical self-assembly and easy tunability by molecular structure modifications, allowing optimization of ferroelectric characteristics and their hybridization with, e.g., semiconductivity. This not only leads to textbook ferroelectric materials that can be used as model systems to understand the general behaviour of ferroics, but also gives rise to previously unobserved effects stemming from the interplay of different functionalities. The core-shell structure of the molecules under the scope enables multiple pathways forrational design by molecular structure modification. This was firstly pursued via peripheral tail engineering on an archetypal self-assembling ferroelectric trialkylbenzene-1,3,5-tricarboxamide (BTA). We found that by shortening the alkyl chain length all the ferroelectric properties can be continuously tuned. In particular, changing the tail from C18H37 to C6H13causes an increase in depolarization activation energy (~0.8 eV to ~1.55 eV), coercive field(~25 V/?m to ~50 V/?m) and remnant polarization (~20 mC/m2 to ~60 mC/m2). The combination of the mentioned characteristics resulted in a record polarization retention time of close to 3 months at room temperature for capacitor devices of the material having the shortest alkyl chain – BTA-C6, which at the time of writing was one of the best results for liquid-crystalline ferroelectrics. Taking one step further, we experimentally demonstrated how introduction of branched-tailsubstituents results in materials with a wide operating temperature range and a data retention time of more than 10 years in thin-film solution-processed capacitor devices already atelevated temperatures with no measurable depolarization at room temperature. The observed differences between linear- and branched-tail compounds were analysed using density functional theory (DFT) and molecular dynamics (MD) simulations. We concluded that morphological factors like improved packing quality and reduced disorder, rather than electrostatic interactions or intra/inter-columnar steric hindrance, underlay the superior properties of the branched-tailed BTAs. Synergistic effects upon blending of compounds with branched and linear sidechains were shown to further improve the materials’ characteristics. Exploiting the excellent ferroelectric performance and the well-defined nanostructure of BTAs, we experimentally determined the Preisach (hysteron) distribution of BTA and confronted it to the one obtained for the semi-crystalline P(VDF:TrFE). This allowed to elucidate how the broadening of the Preisach distribution relates to the materials’ morphology. We further connected the experimental Preisach distribution to the corresponding microscopic switching kinetics. We argue that the combination of the two underlays the macroscopic dispersive switching kinetics as commonly observed for practical ferroelectrics. These insights lead to guidelines for further advancement of ferroelectric materials both for conventional and multi-bit data storage applications. Although having strong differences in the Preisach distribution, BTA and P(VDF:TrFE) both demonstrate negative piezoelectricity – a rare anomalous phenomenon which is characteristic to two-phased materials and has never been observed in small-molecular ferroelectrics. We measured a pronounced negative piezoelectric effect in a whole family of BTAs and revealed its tunability by mesogenic tail substitution and structural disorder. While the large- and small-signal strain in highly ordered thin-film BTA capacitor devices are dominated by intrinsic contributions and originates from piezostriction, rising disorder introduces additional extrinsic factors that boost the large-signal d33 up to ?20 pm/V in short-tailed molecules. Interestingly, homologues with longer mesogenic tails show a large-signal electromechanical response that is dominated by the quadratic Maxwell strain with significant mechanical softening upon polarization switching, whereas the small-signal strain remains piezostrictive. Molecular dynamics and DFT calculations both predict a positive d33 for defect-free BTA stacks. Hence, the measured negative macroscopic d33 is attributed to the presence of structural defects that enable the dimensional effect to dominate the piezoelectric response of BTA thin films. The true multifunctionality of supramolecular discotics manifests when large semiconducting cores surrounded by field-switchable strongly polar moieties are introduced in the structure. We showed how the combination of switchable dipolar side groups and the semiconducting core of the newly synthetized C3-symmetric benzotristhiophene molecule (BTTTA) leads to an ordered columnar material showing continuous tunability from injection- to bulk-limited conductivity modulation. Both these resistive switching mechanisms may lead to the next-generation high-density non-volatile rewritable memory devices with high on/off ratios and non-destructive data readout – the element that has been desperately sought after to enablefully organic flexible electronics. Utbredd elektronisering och det högst aktuella fenomenet sakernas internet (Internet of Things) ställer höga krav på nästa generations elektroniska system. Produkterna ska vara lätta att framställa med miljövänliga metoder, låg kostnadsproduktion och skalbarhet (t. ex. tryckt elektronik), återvinningsbarhet eller biologisk nedbrytbarhet (gällande engångselektronik), mekanisk flexibilitet (formbara bärbara system), kemisk stabilitet, till och med biokompatibilitet (t. ex. implanterbara system) – dessa är bara några utmaningar som den kommande tekniken behöver övervinna. Organiska material kan åstadkomma alla dessa önskade egenskaper, samtidigt som man skapar unika möjligheter att kombinera flera funktionaliteter till en enda sammansättning som underlättar nydanande komponenter och design. Ferroelektriska material kännetecknas av pyroelektriska, piezoelektriska och dielektriska egenskaper. Denna mångsidighet möjliggör icke-flyktiga minnesenheter, temperatur- och taktila sensorer, olika transduktorer och manöverdon, som alla baseras på förändringar av den ferroelektriska restpolarisationen genom fält-, temperatur- och / eller mekaniska stimuleringar. Diskformade supramolekylära organiska ferroelektriska ämnen ger ytterligare fördelar tack vare deras modifierbara molekylstrukturer och starka hierarkiska självorganisation som staplar diskarna i kolumner. På detta sätt kan lättbearbetningsbara organiska ferroelektriska material med hög restpolarisering och extrem datalagring konstrueras molekylärt. På grund av deras väldefinierade nanostrukturer kan sådana material användas som modellsystem för att förstå det allmänna beteendet hos polykristallina ferroelektriska material. De uppvisar också ensällsynt negativ piezoelektricitet som är atypisk för små molekylära material och härrör från deras komplexa nanostruktur. Den verkliga multifunktionaliteten hos diskformade supramolekylära ämnen framträder när stora halvledande kärnor omgivna av starkt polära delar, som är växlingsbara via ett elektriskt fält, introduceras i strukturen. Oöverträffad resistiv omkoppling, inducerad av den asymmetriska laddningstransporten beroende på polarisationsriktningen med rekordhög datalagringstid, upptäcktes efter optimering av molekylstrukturen. Även en konceptuellt enklare resistiv omkopplingsmekanism bunden till en modulation av laddningsinjektionsbarriären genom gränssnittsdipolerna observerades. Båda dessa fenomen kan bidra till nästa generations icke-flyktiga överskrivningsbara minnesenheter med högdensitet, stora på av-förhållanden, och icke-destruktiv dataavläsning – vilket är kritiskt för att möjliggöra helt organisk flexibel elektronik.

Organic Ferroelectric Materials and Applications aims to bring an up-to date account of the field with discussion of recent findings. This book presents an interdisciplinary resource for scientists from both academia and industry on the science and applications of molecular organic piezo- and ferroelectric materials. The book addresses the fundamental science of ferroelectric polymers, molecular crystals, supramolecular networks, and other key and emerging organic materials systems. It touches on important processing and characterization methods and provides an overview of current and emerging applications of organic piezoelectrics and ferroelectrics for electronics, sensors, energy harvesting, and biomedical technologies. Organic Ferroelectric Materials and Applications will be of special interest to those in academia or industry working in materials science, engineering, chemistry, and physics. - Provides an overview of key physical properties of the emerging piezoelectric and ferroelectric molecular and supramolecular systems - Discusses best practices of processing, patterning, and characterization methods and techniques - Addresses current and emerging applications for electronics, materials development, sensors, energy harvesting, and biomedical technologies

The continued digitalization of our society means that more and more things are getting connected electronically. Since currently used inorganic electronics are not well suited for these new applications because of costs and environmental issues, organic electronics can play an important role here. These essentially plastic materials are cheap to produce and relatively easy to recycle. Unfortunately, their poor performance has so far hindered widespread application beyond displays. One key component of any electronic device is the memory. For organic electronics several technologies are being investigated that could serve as memories. One of these are the ferroelectrics, materials that have a spontaneous electrical polarization that can be reversed with an electric field. This bistable polarization which shows hysteresis makes these materials excellent candidates for use as memories. This thesis focuses on a specific type of organic ferroelectric, the supramolecular discotics. These materials consist of disk?like molecules that form columns in which all dipolar groups are aligned, giving a macroscopic ferroelectric polarization. Of particular interest are the benzenetricarboxamides (BTA), which are used as a model system for the whole class of discotic ferroelectrics. BTA uses a core?shell architecture which allows for easy modification of the molecular structure and thereby the ferroelectric properties. To gain a deeper understanding of the switching processes in this organic ferroelectric BTA, both microscopic and analytical modeling are used. This is supported by experimental data obtained through electrical characterization. The microscopic model reduces the material to a collection of dipoles and uses electrostatics to calculate the probability that these dipoles flip. These flipping rates are the input for a kinetic Monte Carlo simulation (kMC), which simulates the behavior of the dipoles over time. With this model we simulated three different switching processes on experimental time and length scales: hysteresis loops, spontaneous depolarization, and switching transients. The results of these simulations showed a good agreement with experiments and we can rationalize the obtained parameter dependencies in the framework of thermally activated nucleation limited switching (TA?NLS). The microscopic character of the model allows for a unique insight into the nucleation process of the polarization switching. We found that nucleation happens at different locations for field driven polarization switching as compared to spontaneous polarization switching. Field?driven nucleation happens at the contacts, whereas spontaneous depolarization starts at defects. This means that retention times in disordered ferroelectrics could be improved by reducing the disorder, without affecting the coercive field. Detailed analysis of the nucleation process also revealed a critical nucleation volume that decreases with applied field, which explains the Merz?like field?dependence of the switching time observed in experiments. In parallel to these microscopic simulations we developed an analytical framework based on the theory of TA?NLS. This framework is mainly focused on describing the switching transients of disordered ferroelectrics. It can be combined with concepts of the Preisach model, which considers a non?ideal ferroelectric as a collection of ideal hysterons. We were able to relate these hysterons and the distribution in their up? and down?switching fields to the microscopic structure of the material and use the combined models to explain experimentally observed dispersive switching kinetics. Whereas ferroelectrics on their own could potentially serve as memories, the readout of ferroelectric memories becomes easier if they are combined with semiconductors. We have introduced several molecular materials following the same design principle of a core?shell structure, which uniquely combine ferroelectricity and semiconductivity in one material. The experimental IV?curves of these materials could be described using an asymmetric Marcus hopping model and show their potential as memories. The combination of modeling and experimental work in this thesis thereby provides an increased understanding of organic ferroelectrics, which is crucial for their application as memories.

Metal–organic frameworks (MOFs) are porous crystalline polymers constructed by metal sites and organic building blocks. Since the discovery of MOFs in the 1990s, they have received tremendous research attention for various applications due to their high surface area, controllable morphology, tunable chemical properties, and multifunctionalities, including MOFs as precursors and self-sacrificing templates for synthesizing metal oxides, heteroatom-doped carbons, metal-atoms encapsulated carbons, and others. Thus, awareness and knowledge about MOFs and their derived nanomaterials with conceptual understanding are essential for the advanced material community. This breakthrough new volume aims to explore down-to-earth applications in fields such as biomedical, environmental, energy, and electronics. This book provides an overview of the structural and fundamental properties, synthesis strategies, and versatile applications of MOFs and their derived nanomaterials. It gives an updated and comprehensive account of the research in the field of MOFs and their derived nanomaterials. Whether as a reference for industry professionals and nanotechnologists or for use in the classroom for graduate and postgraduate students, faculty members, and research and development specialists working in the area of inorganic chemistry, materials science, and chemical engineering, this is a must-have for any library.

The combination of supramolecular chemistry, inorganic solids, and nanotechnology has already led to significant advances in many areas such as sensing, controlled motion, and delivery. By making possible an unprecedented tunability of the properties of nanomaterials, these techniques open up whole new areas of application for future supramolecular concepts. The Supramolecular Chemistry of Organic–Inorganic Hybrid Materials gathers current knowledge on the subject and provides an overview of the present state and upcoming challenges in this rapidly growing, highly cross- or interdisciplinary research field. The book details how these designed materials can improve existing materials or generate novel functional features such as chemical amplification, cooperative binding and signal enhancement that are difficult or not at all achievable by classical organic supramolecular chemistry. It also discusses issues related to nanofabrication or nanotechnology such as the directed and controlled assembly or disassembly, biomimetic functions and strategies, and the gating and switching of surface functions or morphology.

Functional Materials Processing for Switchable Device Modulation focuses on the advances of nanofabrication that underpin emerging technologies, including electronic devices. The book provides readers with a broad view of the materials' perspectives, including historical context and background, along with future opportunities for smart electronic and switchable devices. A major focus in the book is on the research and development of synthetic materials for spectroscopic analysis which broadly deals with science and technology of materials on the atomic and molecular scale. The book reviews the materials and advances in research for switchable electronics for bioelectronic, sensing and optoelectronic applications. In addition, key challenges and emerging opportunities in innovations in surface modification and novel functional materials device implementation for industrial scale reproducibility are discussed. The book covers the applications and market potential for a variety of media, including mirrors, glazing/coatings, and display products. The physics, electrochemistry, device design and materials are detailed, with performance compared between the most relevant and emerging switchable technologies. - Addresses the most interesting advances in switchable devices for bioelectronics, electronics, optoelectronics and sensing applications - Includes a special emphasis on materials design, processing and fabrication of switchable devices to realize large-scale industry applications - Compares the performance of existing innovative switchable devices - Reviews the remaining barriers to commercialization, along with opportunities to address these challenges

This is the fifth set of Handbook of Porphyrin Science.Porphyrins, phthalocyanines and their numerous analogues and derivatives are materials of tremendous importance in chemistry, materials science, physics, biology and medicine. They are the red color in blood (heme) and the green in leaves (chlorophyll); they are also excellent ligands that can coordinate with almost every metal in the Periodic Table. Grounded in natural systems, porphyrins are incredibly versatile and can be modified in many ways; each new modification yields derivatives, demonstrating new chemistry, physics and biology, with a vast array of medicinal and technical applications.As porphyrins are currently employed as platforms for study of theoretical principles and applications in a wide variety of fields, the Handbook of Porphyrin Science represents a timely ongoing series dealing in detail with the synthesis, chemistry, physicochemical and medical properties and applications of polypyrrole macrocycles. Professors Karl Kadish, Kevin Smith and Roger Guilard are internationally recognized experts in the research field of porphyrins, each having his own separate area of expertise in the field. Between them, they have published over 1500 peer-reviewed papers and edited more than three dozen books on diverse topics of porphyrins and phthalocyanines. In assembling the new volumes of this unique handbook, they have selected and attracted the very best scientists in each sub-discipline as contributing authors.This handbook will prove to be a modern authoritative treatise on the subject as it is a collection of up-to-date works by world-renowned experts in the field. Complete with hundreds of figures, tables and structural formulas, and thousands of literature citations, all researchers and graduate students in this field will find the Handbook of Porphyrin Science an essential, major reference source for many years to come.

Nanostructured Thin Films: Fundamentals and Applications presents an overview of the synthesis and characterization of thin films and their nanocomposites. Both vapor phase and liquid phase approaches are discussed, along with the methods that are sufficiently attractive for large-scale production. Examples of applications in clean energy, sensors, biomedicine, anticorrosion and surface modification are also included. As the applications of thin films in nanomedicine, cell phones, solar cell-powered devices, and in the protection of structural materials continues to grow, this book presents an important research reference for anyone seeking an informed overview on their structure and applications. - Shows how thin films are being used to create more efficient devices in the fields of medicine and energy harvesting - Discusses how to alter the design of nanostructured thin films by vapor phase and liquid phase methods - Explores how modifying the structure of thin films for specific applications enhances their performance

Comprehensive Inorganic Chemistry II, Nine Volume Set reviews and examines topics of relevance to today’s inorganic chemists. Covering more interdisciplinary and high impact areas, Comprehensive Inorganic Chemistry II includes biological inorganic chemistry, solid state chemistry, materials chemistry, and nanoscience. The work is designed to follow on, with a different viewpoint and format, from our 1973 work, Comprehensive Inorganic Chemistry, edited by Bailar, Emeléus, Nyholm, and Trotman-Dickenson, which has received over 2,000 citations. The new work will also complement other recent Elsevier works in this area, Comprehensive Coordination Chemistry and Comprehensive Organometallic Chemistry, to form a trio of works covering the whole of modern inorganic chemistry. Chapters are designed to provide a valuable, long-standing scientific resource for both advanced students new to an area and researchers who need further background or answers to a particular problem on the elements, their compounds, or applications. Chapters are written by teams of leading experts, under the guidance of the Volume Editors and the Editors-in-Chief. The articles are written at a level that allows undergraduate students to understand the material, while providing active researchers with a ready reference resource for information in the field. The chapters will not provide basic data on the elements, which is available from many sources (and the original work), but instead concentrate on applications of the elements and their compounds. Provides a comprehensive review which serves to put many advances in perspective and allows the reader to make connections to related fields, such as: biological inorganic chemistry, materials chemistry, solid state chemistry and nanoscience Inorganic chemistry is rapidly developing, which brings about the need for a reference resource such as this that summarise recent developments and simultaneously provide background information Forms the new definitive source for researchers interested in elements and their applications; completely replacing the highly cited first edition, which published in 1973

This book provides an introduction to nanogenerators, which are the newest technological advancement in the field of energy conversion. Chapters discuss the physics behind energy conversion using detailed research results and experimental techniques for fabricating triboelectric and piezoelectric devices, as well as nanogenerators in the field of biomedicine and the construction of stretchable electrodes for wearable devices.