Author: Hassan Abdalla
Publisher:
ISBN: 9789176853528
Category : Electronic books
Languages : en
Pages : 100

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Author: Robin Kimber
Publisher:
ISBN:
Category :
Languages : en
Pages :

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This work describes the application of Kinetic Monte Carlo (KMC) modelling technique to organic photovoltaic (OPV) devices. Such devices are an exciting and relatively new form of photovoltaic (PV) technology, which can help bring solar power to the mass market using low energy processing methods, and materials that are cheap, and have several novel characteristics, such as being lightweight, flexible, and potentially even translucent. The modelling technique and many of the results found here are also applicable to other organic devices, such as organic light-emitting displays (OLEDs), as the underlying device physics is very similar. Following an introduction and discussions on the theoretical basis of the work and its computational implementation, the work described in the thesis falls into three main sections: Firstly, an evaluation is performed as to the accuracy of the First Reaction Method (FRM), a means of reducing the computational complexity of KMC simulations. Although this method is widely used, its accuracy when used to model OPV devices has never been satisfactorily evaluated, leading it to be questioned by some authors. Hence, its accuracy under a range of scenarios relevant for OPV simulations was tested and quantified. The findings presented here confirm its validity within the field and disorder ranges that are applicable to OPV device operation, and also give some insight into low-field geminate separation dynamics. Secondly, the KMC methodology, with the FRM approximation, is applied to the investigation of the role of device morphology in determining OPV efficiency. Morphology optimisation has frequently been identified as being key to future device design, and the KMC methodology is unique in its ability to examine this. Furthermore, as the popularity of using self-assembled bicontinuous nanostructures in OPVs grows, it is useful to evaluate their potential impact on OPV efficiency, using the insight gained from investigating morphology in general. Among the main conclusions reached from this work, it was determined that one of the key limiting factors in the efficiency of devices is the angle of the heterojunctions to the field, which is a feature of the device morphology. It was also found that, because of this, bicontinuous structures are unlikely to greatly improve OPV efficiency. Thirdly, modelling was performed in an attempt to reproduce the quantitative experimental characteristics of PFB:F8BT devices. This was achieved through first modelling individual charge mobility in the two polymers in question, and quantifying the effects of different forms of disorder. Having found disorder descriptions that could reproduce the single carrier mobility of both PFB and F8BT, as deduced by Blakesley et. al. using drift-diffusion modelling, this disorder description was applied to single layer devices, in order to deduce the injection barrier. Finally, the disorder and injection barriers deduced were combined with optical modelling to reproduce full photovoltaic behaviour. This was generally found to be successful, and therefore potentially gives some real insight into the nature of polymer disorder, whilst also validating the KMC model used in this thesis. An additional implication of this work is that the KMC model can, in the future, be applied to experimental data which cannot be satisfactorily modelled using drift-diffusion simulations.

Author: Sergei Baranovski
Publisher: John Wiley & Sons
ISBN: 0470095059
Category : Technology & Engineering
Languages : en
Pages : 498

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Book Description
The field of charge conduction in disordered materials is a rapidly evolving area owing to current and potential applications of these materials in various electronic devices This text aims to cover conduction in disordered solids from fundamental physical principles and theories, through practical material development with an emphasis on applications in all areas of electronic materials. International group of contributors Presents basic physical concepts developed in this field in recent years in a uniform manner Brings up-to-date, in a one-stop source, a key evolving area in the field of electronic materials

Author: Pascal Kordt
Publisher: Walter de Gruyter GmbH & Co KG
ISBN: 3110473879
Category : Science
Languages : en
Pages : 344

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Book Description
In the field of organic semiconductors researchers and manufacturers are faced with a wide range of potential molecules. This work presents concepts for simulation-based predictions of material characteristics starting from chemical stuctures. The focus lies on charge transport – be it in microscopic models of amorphous morphologies, lattice models or large-scale device models. An extensive introductory review, which also includes experimental techniques, makes this work interesting for a broad readership. Contents: Organic Semiconductor Devices Experimental Techniques Charge Dynamics at Dierent Scales Computational Methods Energetics and Dispersive Transport Correlated Energetic Landscapes Microscopic, Stochastic and Device Simulations Parametrization of Lattice Models Drift–Diusion with Microscopic Link

Author: Pascal Kordt
Publisher: Walter de Gruyter GmbH & Co KG
ISBN: 3110473631
Category : Science
Languages : en
Pages : 202

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Book Description
In the field of organic semiconductors researchers and manufacturers are faced with a wide range of potential molecules. This work presents concepts for simulation-based predictions of material characteristics starting from chemical stuctures. The focus lies on charge transport – be it in microscopic models of amorphous morphologies, lattice models or large-scale device models. An extensive introductory review, which also includes experimental techniques, makes this work interesting for a broad readership. Contents: Organic Semiconductor Devices Experimental Techniques Charge Dynamics at Dierent Scales Computational Methods Energetics and Dispersive Transport Correlated Energetic Landscapes Microscopic, Stochastic and Device Simulations Parametrization of Lattice Models Drift–Diusion with Microscopic Link

Author: Johannes Widmer
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Author: Yulong Shen
Publisher:
ISBN:
Category : Charge transfer devices (Electronics)
Languages : en
Pages : 262

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Book Description

Author: Victor I. Klimov
Publisher: CRC Press
ISBN: 1420079271
Category : Technology & Engineering
Languages : en
Pages : 485

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Book Description
A review of recent advancements in colloidal nanocrystals and quantum-confined nanostructures, Nanocrystal Quantum Dots is the second edition of Semiconductor and Metal Nanocrystals: Synthesis and Electronic and Optical Properties, originally published in 2003. This new title reflects the book’s altered focus on semiconductor nanocrystals. Gathering contributions from leading researchers, this book contains new chapters on carrier multiplication (generation of multiexcitons by single photons), doping of semiconductor nanocrystals, and applications of nanocrystals in biology. Other updates include: New insights regarding the underlying mechanisms supporting colloidal nanocrystal growth A revised general overview of multiexciton phenomena, including spectral and dynamical signatures of multiexcitons in transient absorption and photoluminescence Analysis of nanocrystal-specific features of multiexciton recombination A review of the status of new field of carrier multiplication Expanded coverage of theory, covering the regime of high-charge densities New results on quantum dots of lead chalcogenides, with a focus studies of carrier multiplication and the latest results regarding Schottky junction solar cells Presents useful examples to illustrate applications of nanocrystals in biological labeling, imaging, and diagnostics The book also includes a review of recent progress made in biological applications of colloidal nanocrystals, as well as a comparative analysis of the advantages and limitations of techniques for preparing biocompatible quantum dots. The authors summarize the latest developments in the synthesis and understanding of magnetically doped semiconductor nanocrystals, and they present a detailed discussion of issues related to the synthesis, magneto-optics, and photoluminescence of doped colloidal nanocrystals as well. A valuable addition to the pantheon of literature in the field of nanoscience, this book presents pioneering research from experts whose work has led to the numerous advances of the past several years.

Author: Wolfgang Brütting
Publisher: John Wiley & Sons
ISBN: 3527606793
Category : Science
Languages : en
Pages : 554

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Book Description
Filling the gap in the literature currently available, this book presents an overview of our knowledge of the physics behind organic semiconductor devices. Contributions from 18 international research groups cover various aspects of this field, ranging from the growth of organic layers and crystals, their electronic properties at interfaces, their photophysics and electrical transport properties to the application of these materials in such different devices as organic field-effect transistors, photovoltaic cells and organic light-emitting diodes. From the contents: * Excitation Dynamics in Organic Semiconductors * Organic Field-Effect Transistors * Spectroscopy of Organic Semiconductors * Interfaces between Organic Semiconductors and Metals * Analysis and Modeling of Devices * Exciton Formation and Energy Transfer in Organic Light Emitting Diodes * Deposition and Characterization

Author: Kohzoh Masuda
Publisher: Springer Science & Business Media
ISBN: 1468421093
Category : Science
Languages : en
Pages : 187

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Book Description
Great progress has been made in the field of ordinary semiconductor physics and associated technologies. For the time being, if we could use new materials such as organic semiconductors progress in electronics could be accelerated. Characteristics of organic semiconductors that are superior to others are: i) high photo-conductivity under irradiation along with low leakage current in the dark, ii) high sensitivity of the conductivity to various gases and to pressure. iii) possibility of using them in the amorphous state, iv) possibility of making devices of extremely small size, v) large variety of the materials, which makes suitable choice of material component easy. A possible future development is a highly conductive material which could be used for electric power transmission - and which might help solve some of the problems posed by transmission losses. The U.S.-Japan Seminar on Energy and Charge Transfer in Organic Semiconductors was held in Osaka Japan, 6-9 August, 1973. Completed results were summarized and the direction for the future was discussed. Information was exchanged quite freely and actively in a pleasant atmosphere. Many of the papers presented at the seminar are published here but unfortunately a few could not be included. It would give us great pleasure if this seminar could be one step in the further development of the research in this field.