Organic and Molecular Electronics

From Principles to Practice

Michael C. Petty

• Publisher: Wiley
• Year: 2018
• Print ISBN:
  9781118879283
• Edition: 2
• eBook ISBN:
  9781118879252
• Topic: Technology & Engineering
• Subtopic: Materials Science
• Index: Technology & Engineering

An introduction to the interdisciplinary subject of molecular electronics, revised and updated

The revised second edition of Organic and Molecular Electronics offers a guide to the fabrication and application of a wide range of electronic devices based around organic materials and low-cost technologies. Since the publication of the first edition, organic electronics has greatly progressed, as evidenced by the myriad companies that have been established to explore the new possibilities.

The text contains an introduction into the physics and chemistry of organic materials, and includes a discussion of the means to process the materials into a form (in most cases, a thin film) where they can be exploited in electronic and optoelectronic devices. The text covers the areas of application and potential application that range from chemical and biochemical sensors to plastic light emitting displays. The updated second edition reflects the recent progress in both organic and molecular electronics and:

• Offers an accessible resource for a wide range of readers
• Contains a comprehensive text that covers topics including electrical conductivity, optical phenomena, electroactive organic compounds, tools for molecular electronics and much more
• Includes illustrative examples based on the most recent research
• Presents problems at the end of each chapter to help reinforce key points

Written mainly for engineering students, Organic and Molecular Electronics: From Principles to Practice provides an updated introduction to the interdisciplinary subjects of organic electronics and molecular electronics with detailed examples of applications. 

1
Scope of Organic and Molecular Electronics

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CHAPTER MENU

1. 1.1 Introduction
2. 1.2 Organic Materials for Electronics
3. 1.3 Molecular Electronics
4. 1.3.1 Evolution of Microelectronics
5. 1.3.2 Moore’s Laws
6. 1.3.3 Beyond Moore
7. 1.4 The Biological World
8. 1.5 Future Opportunities
9. 1.6 Conclusions
10. Problems
11. References
12. Further Reading

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What's in a name?

1.1 Introduction

The title of this introductory chapter (and the title of the book) suggests two distinct topics. However, the subjects are intimately related. Organic electronics has its origins in materials science and concerns the development of electronic and opto‐electronic devices that exploit the unique macroscopic properties of organic materials. The most successful commercial product to date is the liquid crystal display (LCD). However, following many years of research, organic light‐emitting devices based on dyes and polymers, organic solar cells, organic electronics circuitry, and biochemical sensors are beginning to make their technological marks. The Nobel Prize in Chemistry for 2000 was awarded to three scientists working in the area of organic electronics: Alan Heeger, Alan MacDiarmid, and Hideki Shirakawa, who have made significant contributions to the development of electrically conductive polymers. Much of the current industrially‐oriented organic electronics work is being pursued under names such as plastic electronics or printable electronics, referring to the materials being exploited and the processing technology, respectively.

More challenging is molecular electronics. Here, the focus is on the behaviour of individual organic molecules or groups of molecules, and the precise three‐dimensional positional control of individual atoms and molecules. Topics as diverse as molecular switching, DNA‐electronics, and molecular manufacturing have all been described in the literature. Much of the research activity is directed towards computational architectures that may, one day, rival silicon microelectronics. However, even the most optimistic researchers recognize that this is going to be some time away!

Molecular electronics also falls under the umbrella of nanotechnology. In particular, it exemplifies the ‘bottom‐up’ theme of nanotechnology, which refers to making nanoscale structures by building organic and inorganic architectures atom‐by‐atom, or molecule‐by‐molecule. The physicist Richard Feynman was one of the first to predict a future for molecular‐scale electronics. In a lecture in December 1959, at the annual meeting of the American Physical Society, entitled ‘There's Plenty of Room at the Bottom’, he described how the laws of physics do not limit our ability to manipulate single atoms and molecules. Instead, it was our lack of the appropriate methods for doing so. Feynman correctly predicted that the time would come in which atomically precise manipulation of matter would be possible. Several advances have now been made to suggest that the prophecy was correct. In this respect, a key invention has been scanning probe microscopy.

1.2 Organic Materials for Electronics

Liquid crystals represent a remarkable molecular electronics success story. However, the transformation of these organic compounds into the established display technology of today took many decades. In the latter half of the nineteenth century, researchers discovered several materials whose optical properties behaved in a strange way near their melting points. In 1922, George Friedel presented a liquid crystal classification scheme, but it took until the 1960s for the potential of liquid crystals in display devices to be recognized. From this point, research into liquid crystals and their applications burgeoned. It is encouraging for workers in organic electronics that the relatively unstable (both thermally and chemically) liquid crystal compounds came to form the foundation of such a substantial worldwide industry.

The interest in organic electronics derives from the intriguing electrical and opto‐electrical behaviour of organic materials. Two distinct groups of compounds have been studied – low molecular weight crystalline compounds (molecular crystals) and polymers. In the former category, the photoconductivity of anthracene was discovered in 1906 [1]. However, systematic study of the electrical behaviour of organic molecular solids did not begin until the 1950s [2–4]. The phthalocyanine compounds were one of the first classes of organic molecular crystals to be investigated [2, 3]. These large flat ring‐shaped structures are relatively stable organic materials and demonstrate that the words ‘organic’ and ‘thermally unstable’ need not always go hand‐in‐hand. A further interesting group of organic conductive compounds are charge‐transfer (CT) complexes. In 1954, researchers reported CT complexes with low resistivities in combinations of perylene with iodine or bromine (perylene itself is an insulator) [5]. In 1962, the well‐known electron acceptor molecule tetracyanoquinodimethane (TCNQ) was reported by workers at Dupont. Tetrathiafulvalene (TTF) was synthesized in 1970 and found to be a strong electron donor. In 1973, it was discovered that a combination of these components form a strong CT complex, referred to as TTF‐TCNQ. The solid exhibits almost metallic electrical conductivity.

The first synthetic polymers were produced in the late nineteenth century. These were eventually developed into useful products in the 1940s and 1950s (exploiting their toughness, strength to weight ratio, low cost, and ease of fabrication). At this time, polymeric materials were all good insulators, and the idea that a plastic material might conduct electricity was not generally considered. Polyacetylene is...

Table of contents

• Cover
• Table of Contents
• Preface
• 1 Scope of Organic and Molecular Electronics
• 2 Materials' Foundations
• 3 Electrical Conductivity
• 4 Optical Phenomena
• 5 Electroactive Organic Compounds
• 6 Tools for Molecular Electronics
• 7 Thin Film Processing and Device Fabrication
• 8 Liquid Crystals and Devices
• 9 Plastic Electronics
• 10 Chemical Sensors and Physical Actuators
• 11 Molecular and Nanoscale Electronics
• 12 Bioelectronics
• Appendix
• Index
• End User License Agreement