Charge Injection and Chemistry at the Indium Tin Oxide-organic Interface
Author: Delia J. Markiewicz
Publisher:
Published: 1999
Total Pages: 0
ISBN-13:
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CHARACTERIZATION OF CHARGE INJECTION PROCESSES OF THIN FILMS ON INDIUM TIN OXIDE ELECTRODES USING A NOVEL SPECTROELECTROCHEMICAL TECHNIQUE: POTENTIAL-MODULATED ATTENUATED TOTAL REFLECTANCE SPECTROSCOPY.
Author: Zeynep Araci
Publisher:
Published: 2010
Total Pages: 482
ISBN-13:
DOWNLOAD EBOOKUnderstanding interfacial charge injection processes is one of the key factors needed for development of efficient organic electronic devices, such as biosensors and energy conversion systems, since these processes control the electrical characteristics of these devices. Spectroelectrochemical characterization of electron transfer processes occurring at the electrode - electroactive thin film interface has been evaluated to improve our understanding of charge transfer kinetics using a novel form of electroreflectance spectroscopy, potential-modulated attenuated total reflectance (PM-ATR), which makes it possible to sensitively monitor spectroscopic changes in thin films as a function of applied potential. PM-ATR was used to evaluate three different redox-active films deposited on indium tin oxide (ITO) electrodes to investigate: i) the orientation dependence of charge transfer rates of thin films of biomolecules, ii) surface treatment and modification effects on charge transfer kinetics of conducting polymers and, iii) estimation of rates of electron injection and conduction band edge of semiconductor nanocrystalline materials. First, Prussian blue film as a model system was used successfully to examine the PM-ATR technique for determination of the charge transfer rate constant between ITO and a molecular film. Second, an anisotropic and redox active protein film, cytochrome c, was used to probe charge transfer rates with respect to molecular orientation. The electron transfer rate measured using TM polarized light was four-fold greater than that measured using TE polarized light. These data are the first to correlate a distribution of molecular orientations with a distribution of electron transfer rates in a redox-active molecular film. Third, the effects of ITO surface treatment and modification on charge transfer kinetics on a conducting polymer, poly(3,4-ethylenedioxythiophene/)/poly(styrenesulfonate) (PEDOT/PSS), were studied. The apparent interfacial charge transfer rate constant for PEDOT/PSS on ITO has been reported for the first time which cannot be measured otherwise with conventional electrochemistry due to high non-Faradaic background of PEDOT/PSS films. Fourth, PM-ATR enabled characterization of reversible redox processes between submonolayer coverages of surface-tethered, CdSe nanocrystals and ITO for the first time. Optically determined onset potentials for electron injection were used for estimation for the conduction band and valance band energies (ECB and EVB, respectively).
Organic Light-Emitting Materials and Devices
Author: Zhigang Rick Li
Publisher: CRC Press
Published: 2017-12-19
Total Pages: 731
ISBN-13: 1351832662
DOWNLOAD EBOOKOrganic Light-Emitting Materials and Devices provides a single source of information covering all aspects of OLEDs, including the systematic investigation of organic light-emitting materials, device physics and engineering, and manufacturing and performance measurement techniques. This Second Edition is a compilation of the advances made in recent years and of the challenges facing the future development of OLED technology. Featuring chapters authored by internationally recognized academic and industrial experts, this authoritative text: Introduces the history, fundamental physics, and potential applications of OLEDs Reviews the synthesis, properties, and device performance of electroluminescent materials used in OLEDs Reflects the current state of molecular design, exemplifying more than 600 light-emitting polymers and highlighting the most efficient materials and devices Explores small molecules-based OLEDs, detailing hole- and electron-injection and electron-transport materials, electron- and hole-blocking materials, sensitizers, and fluorescent and phosphorescent light-emitting materials Describes solution-processable phosphorescent polymer LEDs, energy transfer processes, polarized OLEDs, anode materials, and vapor deposition manufacturing techniques employed in OLED fabrication Discusses flexible display, the backplane circuit technology for organic light-emitting displays, and the latest microstructural characterization and performance measurement techniques Contains abundant diagrams, device configurations, and molecular structures clearly illutrating the presented ideas Organic Light-Emitting Materials and Devices, Second Edition offers a comprehensive overview of the OLED field and can serve as a primary reference for those needing additional information in any particular subarea of organic electroluminescence. This book should attract the attention of materials scientists, synthetic chemists, solid-state physicists, and electronic device engineers, as well as industrial managers and patent lawyers engaged in OLED-related business areas.
Chemistry of Functional Materials Surfaces and Interfaces
Author: Andrei Honciuc
Publisher: Elsevier
Published: 2021-02-19
Total Pages: 282
ISBN-13: 0128231939
DOWNLOAD EBOOKChemistry of Functional Materials Surfaces and Interfaces: Fundamentals and Applications gives a descriptive account of interfacial phenomena step-by-step, from simple to complex, to provide readers with a strong foundation of knowledge in interfacial materials chemistry. Many case studies are provided to give real-world examples of problems and their solutions, allowing readers to make the connection between fundamental understanding and applications. Emerging applications in nanomaterials and nanotechnology are also discussed. Throughout the book, the author explains the common interface and surface equations, models, methods, and applications in the creation of functional materials. The goal of Chemistry of Functional Materials Surfaces and Interfaces is to provide readers with the basic understanding of the common tools of surface and interface chemistry for application in materials science and nanotechnology. This book is suitable for researchers and practitioners in the disciplines of materials science and engineering and surface and interface chemistry. Includes numerous real-world examples and case studies throughout Addresses emerging applications of interfacial materials chemistry in nanomaterials and nanotechnology Provides the foundational concepts of surface and interfacial science with models, equation, and methods
Hybrid Organic-Inorganic Interfaces
Author: Marie Helene Delville
Publisher: John Wiley & Sons
Published: 2017-12-04
Total Pages: 1009
ISBN-13: 3527807101
DOWNLOAD EBOOKHybrid organic-inorganic materials and the rational design of their interfaces open up the access to a wide spectrum of functionalities not achievable with traditional concepts of materials science. This innovative class of materials has a major impact in many application domains such as optics, electronics, mechanics, energy storage and conversion, protective coatings, catalysis, sensing and nanomedicine. The properties of these materials do not only depend on the chemical structure, and the mutual interaction between their nano-scale building blocks, but are also strongly influenced by the interfaces they share. This handbook focuses on the most recent investigations concerning the design, control, and dynamics of hybrid organic-inorganic interfaces, covering: (i) characterization methods of interfaces, (ii) innovative computational approaches and simulation of interaction processes, (iii) in-situ studies of dynamic aspects controlling the formation of these interfaces, and (iv) the role of the interface for process optimization, devices, and applications in such areas as optics, electronics, energy and medicine.
Charge Injection and Transport in Organic Semiconductors
Author: Yulong Shen
Publisher:
Published: 2004
Total Pages: 262
ISBN-13:
DOWNLOAD EBOOKOLED Fundamentals
Author: Daniel J. Gaspar
Publisher: CRC Press
Published: 2015-05-15
Total Pages: 474
ISBN-13: 1466515198
DOWNLOAD EBOOKA Comprehensive Source for Taking on the Next Stage of OLED R&DOLED Fundamentals: Materials, Devices, and Processing of Organic Light-Emitting Diodes brings together key topics across the field of organic light-emitting diodes (OLEDs), from fundamental chemistry and physics to practical materials science and engineering aspects to design and ma
Unimolecular and Supramolecular Electronics I
Author: Robert M. Metzger
Publisher: Springer Science & Business Media
Published: 2012-01-10
Total Pages: 317
ISBN-13: 3642272835
DOWNLOAD EBOOKCharge Transport in Organic Semiconductors, by Heinz Bässler and Anna Köhler. Frontiers of Organic Conductors and Superconductors, by Gunzi Saito and Yukihiro Yoshida. Fullerenes, Carbon Nanotubes, and Graphene for Molecular Electronics, by Julio R. Pinzón, Adrián Villalta-Cerdas and Luis Echegoyen. Current Challenges in Organic Photovoltaic Solar Energy Conversion, by Cody W. Schlenker and Mark E. Thompson.- Molecular Monolayers as Semiconducting Channels in Field Effect Transistors, by Cherie R. Kagan. Issues and Challenges in Vapor-Deposited Top Metal Contacts for Molecule-Based Electronic Devices, by Masato M. Maitani and David L. Allara. Spin Polarized Electron Tunneling and Magnetoresistance in Molecular Junctions, by Greg Szulczewski.
Modification of Indium Tin Oxide Surfaces with Phosphonic Acid Functionalized Phthalocyanines
Author: Luis E. Oquendo Galarza
Publisher:
Published: 2014
Total Pages: 217
ISBN-13:
DOWNLOAD EBOOKThe overall efficiency of organic photovoltaics cells (OPVs) is influenced by the nature of the charge injection barrier at the transparent conducting oxide (TCO) bottom contact. Modification of the transparent conducting oxide (TCO)/organic interface with an electroactive molecular monolayer will potentially create a robust ohmic contact that will influence the efficiency of hole injection into the TCO. Asymmetric zinc Phthalocyanines (ZnPc) with a flexible phosphonic acid (PA) linker have been synthesized and used to modify indium tin oxide (ITO) surfaces. The adsorption of PA functionalized asymmetric ZnPcs on an ITO/waveguide was monitored using attenuated total reflectance (ATR) spectroscopy. Polarized dependent ATR spectroscopy was used to determine the orientation of these absorbed subpopulations species on ITO modified surfaces as a function of wavelength using transverse electric (TE) or transverse magnetic (TM) polarized light. The first oxidation potential on absorbed monolayers was found by cyclic voltammetry to be resolved into two peaks indicative of two electrochemically distinct subpopulations of molecules, atributed to aggregates and monomerics forms of PA functionalized ZnPcs. Potential modulated ATR (PM-ATR) spectroelechtrochemistry was employed to measure the charge transfer rates constants (k(s, app)) at ITO modified surfaces using TE and TM polarized light. Faster charge transfer rate constants were found for molecules with a smaller tunneling distance. A k(s, app) of 3.9 x 104 s−1 represents the fastest rate measured for PA functionalized ZnPc chromophore tethered to an ITO waveguide electrode by PM-ATR. We synthesized and characterized the first examples of PA functionalized RuPcs to investigate the effect of molecular orientation on charge transfer properties at an ITO/organic interface. PA functionalized RuPcs have the ability to coordinate axial ligand to suppress aggregation, providing the flexibility of connecting the anchoring group through the axial position of the metal and allowing chemisorption of the molecule in plane with ITO. Cyclic voltammetry and ATR UV/vis spectroscopy on the modified ITO surface demonstrated a surface composition of a closed-packed monolayer of monomeric species. Measurement of the charge transfer rates constants demonstrated that RuPc anchored to ITO exhibited slow rates compared to corresponding surface bound ZnPcs. Finally, we describe the synthesis and characterization of a new PA functionalized N-pyridinyl perylenediimide (PDI)-RuPc donor-acceptor dyad capable of chemisorption to ITO surfaces as a molecular-level heterojunction system to study photo induced charge separated states. The developed ensemble was proven to be stable on ITO for further study of charge injection events from the dyad to the oxide surface.
Modification of Indium-Tin Oxide Surfaces: Enhancement of Solution Electron Transfer Rates and Efficiencies of Organic Thin-Layer Devices
Author: Chet Carter
Publisher:
Published: 2006
Total Pages: 648
ISBN-13:
DOWNLOAD EBOOKThis dissertation has focused on the study of the ITO/organic heterojunction and the chemistries therein, it proposes appropriate strategies that enhance the interfacial physical and electronic properties for charge injection with application to organic thin-layer devices. We focused on four major aspects of this work: i) To characterize the ITO surface and chemistries that may be pertinent to interaction with adjacent organic layers in a device configuration. This developed a working model of surface and provided a foundation for modification strategies. Characterization of the electronic properties of the surface indicate less than 5% of the geometrical surface is responsible for the bulk of current flow while the rest is electrically inactive. ii) To determine the extent to which these chemistries are variable and propose circumstances where compositional changes can occur. It is shown that the surface chemistry of ITO is heterogeneous and possible very dynamic with respect to the surrounding environment. iii) To propose a strategy for modification of the interface. Modification of ITO surfaces by small molecules containing carboxylic acid functionalities is investigated. Enhancements in the electron transfer rate coefficient were realized after modification of the ITO electrode. The enhancements are found to stem from a light etching mechanism. Additionally, an elecro-catalytic effect was observed with some of the modifiers. iv) Apply these modifications to organic light emitting diodes (OLEDs) and organic photovoltaic devices (OPVs). Enhancements seen in solution electrochemical experiments are indicative of the enhancements seen for solid state devices. Modifications resulted in substantially lower leakage currents (3 orders of magnitude in some cases) as well as nearly doubling the efficiency. An additional chapter describesthe creation and characterization of electrochemically grown polymer nano-structures based on blazed angle diffraction gratings. The discussion details the micro-contact printing process and the electro-catalytic growth of the conductive polymers PANI and PEDOT to form diffraction grating structures in their own right. The resulting diffraction efficiency of these structures is shown to be sensitive to environmental conditions outlining possible uses as chemical sensors. This is demonstrated by utilizing these structures as working pH and potentiometric sensors based on the changing diffraction efficiency.
