Download or read book Charge Transport in Molecular Junctions and Microfluidic Devices written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mechanical Control of Charge Transport and Chemical Reactivity in Molecular Junctions written by Leopoldo Meja̕ Restrepo and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Charge transport plays a critical role in a wide range of molecular processes including photosynthesis, redox catalysis, energy storage, biological signaling, and the operation of molecular electronic devices. Understanding and controlling these key events requires establishing how molecular structure influences charge transport and designing physically realizable strategies to manipulate them. This thesis advances the theory, simulation, and interpretation of charge transport experiments in molecular junctions and identifies novel avenues to use external mechanical stimuli to control chemistry and physics in this nanoscale setting. The reason why we focus on molecular junction experiments is because they enable the manipulation of individual molecules and the characterization of their response to external stimuli such as mechanical forces, bias voltages, and electro-magnetic fields. Such a controllable setting is ideal to establish structure-charge transport relations at the single-molecule limit that can inform and resolve the individual molecular contributions to bulk phenomena. We first demonstrate that conductance can act as a sensitive probe of conformational dynamics during the mechanical pulling of molecular junctions. These advances offer an efficient solution to experimentally monitor conformational dynamics at the single-molecule limit. Next, we bridge molecular conductance with mechanochemistry and investigate how to mechanically onset and electrically monitor chemical reactivity in single molecules. In particular, we demonstrate mechanically controlled association and rupture reactions in molecular junctions and show that simultaneous measurements of force and conductance are able to signal reactive events that cannot be distinguished by force or conductance alone. The computations are based on atomistic molecular dynamics and nonequilibrium Green's functions computations of electron transport. At the methodological level, we clarify the utility of the Landauer equation for computing charge transport across molecular junctions immersed in a thermal environment such as solvent. The Landauer equation is central to the modeling of molecular electronics experiments. However, it supposes that the current is coherent (solely due to quantum tunneling) and does not capture the possible influence of the environment in the net current. We isolate physical conditions that require an analysis beyond Landauer and use them to identify chemical motifs capable of stabilizing coherent, incoherent, and intermediate transport mechanisms. Molecular junction experiments typically record the conductance of thousands of freshly formed junctions and report histograms of conductance events. Here, we construct a microscopic theory of such conductance histograms by merging the theory of force spectroscopy developed in biophysics with molecular conductance. The theory enhances the information that can be extracted from molecular electronics experiments, and can be employed to develop schemes to narrow the width of the histograms as desirable for spectroscopic applications and molecular device design. Further, the theory opens key opportunities to atomistically model the conductance histograms, as needed to bridge the gap between theory and experiments."--Pages viii-ix.
Download or read book Charge Transport in Molecular Junctions with Novel Two dimensional Contacts written by Shuhui Tao and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nanoelectronics Devices Design Materials and Applications Part I written by Gopal Rawat and published by Bentham Science Publishers. This book was released on 2023-10-31 with total page 449 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanoelectronics Devices: Design, Materials, and Applications provides information about the progress of nanomaterial and nanoelectronic devices and their applications in diverse fields (including semiconductor electronics, biomedical engineering, energy production and agriculture). The book is divided into two parts. The editors have included a blend of basic and advanced information with references to current research. The book is intended as an update for researchers and industry professionals in the field of electronics and nanotechnology. It can also serve as a reference book for students taking advanced courses in electronics and technology. The editors have included MCQs for evaluating the readers’ understanding of the topics covered in the book. Topics covered in Part 1 include basic knowledge on nanoelectronics with examples of testing different device parameters. - The present, past, and future of nanoelectronics, - An introduction to Nanoelectronics and applicability of Moore's law - Transport of charge carrier, electrode, and measurement of device parameters - Fermi level adjustment in junction less transistor, - Non-polar devices and their simulation - The negative capacitance in MOSFET devices - Effect of electrode in the device operation - Second and Sixth group semiconductors, - FinFET principal and future, Electronics and optics integration for fast processing and data communication - Batteryless photo detectors - Solar cell fabrication and applications - Van der Waals assembled nanomaterials
Download or read book Nanogap Electrodes written by Tao Li and published by John Wiley & Sons. This book was released on 2021-07-14 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt: Unique in its scope, this book comprehensively combines various synthesis strategies with applications for nanogap electrodes. Clearly divided into four parts, the monograph begins with an introduction to molecular electronics and electron transport in molecular junctions, before moving on to a whole section devoted to synthesis and characterization. The third part looks at applications with single molecules or self-assembled monolayers, and the whole is rounded off with a section on interesting phenomena observed using molecular-based devices.
Download or read book Theoretical Analysis of the Conduction Properties of Self assembled Molecular Tunnel Junctions written by Cameron Nickle and published by . This book was released on 2020 with total page 123 pages. Available in PDF, EPUB and Kindle. Book excerpt: As the size scale of electrical devices approach the atomic scale. Moore’s law is predicted to be over for semiconductor devices. Studies into the replacement of semiconductor technology with organic devices was first predicted by Avriam and Ratner[1] in 1974. Since then significant research into molecular based organic devices has been conducted. The work presented in this dissertation explores the theoretical frameworks used to model transport through molecular junctions. We present studies which seek to garner a better understanding of the charge transport through molecular junctions and how the conduction properties can be optimized. We show that a single atom can change a molecule from an insulator to a conductor. We also study the effects of sigma and pi bridges on molecular rectification. We will then show molecular devices that act as viable electrical static and dynamic switches. The studies presented here help to demonstrate the viability of organic devices in the forms of rectifiers and switches with applications ranging from the replacement of traditional semiconductor devices to neuromorphic computing.
Download or read book Charge Transport in Organic Materials written by Matthias H. Hettler and published by . This book was released on 2008 with total page 231 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Electrical and Optical Characterization of Molecular Junctions written by Nazanin Davani and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Electronic transport through molecules has been intensively studied in recent years, due to scientific interest in fundamental questions about charge transport and the technological promise of nanoscale circuitry. A variety of experimental platforms have been developed to electronically probe molecular junctions. However, it remains challenging to fabricate reliable electronic contacts to molecules, and the vast majority of molecular electronic architectures are not amenable to standard characterization techniques, such as optical spectroscopy. Interesting phenomena like switching and rectification are observed in molecular junctions. However, due to limited quantitative information about the junction, the mechanism remains unknown and many fundamental questions about electronic transport remain unanswered. The first part of the thesis will introduce the fabrication of Metal-Insulator-Metal (MIM) cross bar junctions using soft deposition technique. In this method, we softly deposit the premade metal contacts that are being supported with a polymer backing layer onto the organic layer. Using this method, we can efficiently fabricate large area, non-shorting devices, which are required for optical characterization of the molecular junctions. Having established a means of fabricating reliable molecular devices, we have investigated the switching mechanism in molecular junctions based on n-type semiconductor Perylene tetracarboxylic diimide (TE-PTCDI) molecules. Using Surface Plasmon Resonance Spectroscopy (SPRS) we have been able to perform simultaneous optical-electrical measurements to study the molecular behavior quantitatively. Using in- situ optical spectroscopy on active molecular junctions, we find that only a small fraction of the molecules are actually switching in the junction. Next, metal filament formation, a common phenomenon in thin film devices has been investigated. Metal filaments are observed to lead to non-molecular conductance variations in molecular junctions. Employing electrical and optical methods, the possible mechanisms responsible for the formation of metal filaments in the junction were studied. Finally, I present the results of our studies on the molecular rectification in C60- diamondoid hybrid molecules in large area junctions, as well as in smaller ensemble of molecules.
Download or read book Encyclopedia of Microfluidics and Nanofluidics written by Dongqing Li and published by Springer Science & Business Media. This book was released on 2008-08-06 with total page 2242 pages. Available in PDF, EPUB and Kindle. Book excerpt: Covering all aspects of transport phenomena on the nano- and micro-scale, this encyclopedia features over 750 entries in three alphabetically-arranged volumes including the most up-to-date research, insights, and applied techniques across all areas. Coverage includes electrical double-layers, optofluidics, DNC lab-on-a-chip, nanosensors, and more.
Download or read book Functional Surface and Charge transfer Arrays written by Jiandi Wan and published by . This book was released on 2007 with total page 486 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: This research is interdisciplinary work in which at least three different but related areas have been involved: fabrication of microfluidic devices, derivatization of solid surfaces and charge transfer processes. We developed a non-lithographic procedure with micrometer resolution. This procedure enables fast and inexpensive prototyping of microfluidic devices made of elastomeric materials. The novelty of this approach is in the "shortcuts" taken during the preparation of the masters for casting the polymer components of the devices. Addition of microposts to the surface of the master allows for the formation of microfluidic channels with circular cross section and smooth walls. We used this new procedure for the fabrication a device for quantitative detection of bacterial spores. In our surface work, we mainly focused on coating glass and silicon surfaces using different silanes and polyethylene glycol (PEG) derivatives. We were able to prepare highly packed and biocompatible surfaces, in which the coatings were covalently attached to the solid substrates. We have developed procedures for controlled formation of permanently adhered high-density monodispersed organic monolayers carrying the desired functionality. The surface derivative reactions were carried out -under relatively mild conditions that were not harmful either for the surfaces of the solid substrates or for biomolecules attached to coating. We employed UV/vis absorption and fluorescence emission spectroscopic techniques for kinetic studies of surfaces with enzymes attached to them. Studies of photoinduced charge transfer processes, which occur either in solution or across a solid-liquid interface, have provided considerable insight into molecular design strategies for systems capable of long distance charge separation, chemical potential storage, and artificial photosynthesis. In our research, we developed a model quarterthiophene anthraquinone system capable of photoinduced electron transfer. Electron transfer rates measured by laser flash photolysis or extracted from fluorescence data were found to be sensitive to the solvent polarity. By adding an external electron acceptor, 2,5-dichloro-1,4-benzoquinone-3-(4-carboxyly) benzoic acid (DCBQ), multistep intra/intermolecular electron transfer was observed. We were also able to immobilize charge transfer arrays to conducting surfaces and induce electron transfer across the interface.
Download or read book Gap Junctions Study Using a Microfluidic Sensor written by Cedric Bathany and published by . This book was released on 2012 with total page 153 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cells in tissues and organs coordinate their activities by communicating with each other, and this communication is mediated by specialized channels, called gap junctions. There are two types of gap junction communications both governed by potential gradients: molecular diffusion and electrolyte transport. Most cells are known to express multiple connexins that form different types of gap junctions. To date, there is no known gap junction blocker which specifically blocks one kind of gap junction channel. Therefore, we have developed a microfluidic sensor for studying intercellular communication in a high throughput manner. The concept of the microfluidic sensor is based on the ability for a multi-stream channel to partition a cell monolayer with different chemically loaded solutions. Numerical simulations were conducted to characterize the performance of the chip in terms of multiple flow control, interface stability and fluid exchange time.^The flexibility of the sensor allowed the characterization of molecular diffusion and electrical coupling. The study of intercellular diffusion of fluorescent probes in Normal Rat Kidney cells confirmed the size dependent permeability through the Cx43. With the aid of a numerical algorithm, we were able to extract the diffusion rate of molecular probes from fluorescent microscopy recordings. The testing of different molecular size fluorescent dyes showed increasing diffusion rates with decreasing molecular weight. A similar experimental configuration gave us the ability to screen different gap junction blockers. The testing of showed homogeneous reduction of the diffusion rate for all tested dyes, while MFA displayed a charge dependent potency. The ability for the sensor to test different dyes or different blockers was also demonstrated in detail. We also measured the electrical intercellular communication via the same microfluidic chip using a sucrose gap configuration.^The use of a non-conductive solution in the middle stream of the tri-stream channel allowed the constriction of electrolyte transport through gap junction channels. Both 1-Heptanol and 2-APB reversibly reduced gap junction communication. The gap junction blockers 1-Heptanol and 2-APB provided distinct kinetics of electrolyte transport alteration, suggesting the presence of two different blocking mechanisms. We also demonstrated the ability to screen candidate blockers such as the ion channel inhibitor, GsMTx-4. The application GsMTx-4 did not show an effect on the gap junction channels. Finally, we studied the effect of the cell substrate stiffness on the gap junctions' activity. The substrate was coated with a layer of Polydimethylsiloxane (PDMS), presenting different stiffness, prior to experimentation.^The study of the molecular diffusion through cells cultured on substrates of different stiffness showed an increase of the molecular permeability with decreasing the substrate stiffness. To understand the link between intercellular diffusion of molecular probes and substrate stiffness, we immunostained proteins playing a role in substrate sensing, such as actin filaments and in the cell-cell junction such as ZO-1. The results showed an increased number of ZO-1 complexes for softer substrates and an increase of the Cx43 complexes at the cell-cell junction, which was responsible for facilitating gap junction mediated molecular diffusion.
Download or read book Charge Transport Study of Functional Molecules Employing Break Junction Techniques Under Potential Control written by and published by . This book was released on 2015 with total page 74 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Molecular Charge Transport written by Constant Marcel Guédon and published by . This book was released on 2012 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Molecular Electronics written by Ari Aviram and published by . This book was released on 1998 with total page 392 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume explores the resurgence of interest in the field of molecular electronics in view of recent advances in such areas as molecular wires, molecular components, fabrication, and assemblies of molecular scale devices and their wiring on surfaces. It shows how molecular electronics offer scientists an opportunity to study and understand a new class of materials, on the molecular level and in isolation, while offering to engineers a new microelectronics technology.
Download or read book Charge Transport in Organic Materials written by Matthias H. Hettler and published by . This book was released on 2008 with total page 231 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Organs on chips written by Yu-suke Torisawa and published by MDPI. This book was released on 2020-05-27 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent advances in microsystems technology and cell culture techniques have led to the development of organ-on-chip microdevices that produce tissue-level functionality, not possible with conventional culture models, by recapitulating natural tissue architecture and microenvironmental cues within microfluidic devices. Since the physiological microenvironments in living systems are mostly microfluidic in nature, the use of microfluidic devices facilitates engineering cellular microenvironments; the microfluidic devices allow for control of local chemical gradients and dynamic mechanical forces, which play important roles in cellular viability and function. The organ-on-chip microdevices have great potential to promote drug discovery and development, to model human physiology and disease, and to replace animal models for efficacy and toxicity testing. Recently, induced pluripotent stem (iPS) cells have been leveraged to develop organs-on-chips, which enable various types of organ models and disease models not possible with primary cells and cell lines. This Special Issue seeks to showcase research papers, short communications, and review articles that focus on: (1) microdevices to mimic or control cellular microenvironment; (2) microdevices to evaluate interactions between different organ models; (3) microdevices to maintain iPS cells or iPSC-derived cells; and (4) sensors and techniques to evaluate drug efficacy or toxicity.
Download or read book Electrokinetically Driven Fluidic Transport in Integrated Three dimensional Microfluidic Devices Incorporating Gold coated Nanocapillary Array Membranes written by and published by . This book was released on 2008 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt:
