Infochemistry information processing at the nanoscale

Infochemistry Infochemistry Information Processing at the Nanoscale Konrad Szaciłowski Faculty of Non-Ferrous Metals, AGH University of Science and Technology, Krakow, Poland and Faculty of Chemistry, Jagiellonian University, Krako´w, Poland This edition first published 2012 #2012 John Wiley and Sons Ltd Registered office John Wiley & Sons Ltd, The Atrium, Southern Gate, Chichester, West Sussex, PO19 8SQ, United Kingdom For details of our global editorial offices, for customer services and for information about how to apply for permission to reuse the copyright material in this book please see our website at www.wiley.com The right of the author to be identified as the author of this work has been asserted in accordance with the Copyright, Designs and Patents Act 1988 All rights reserved No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, except as permitted by the UK Copyright, Designs and Patents Act 1988, without the prior permission of the publisher Wiley also publishes its books in a variety of electronic formats Some content that appears in print may not be available in electronic books Designations used by companies to distinguish their products are often claimed as trademarks All brand names and product names used in this book are trade names, service marks, trademarks or registered trademarks of their respective owners The publisher is not associated with any product or vendor mentioned in this book This publication is designed to provide accurate and authoritative information in regard to the subject matter covered It is sold on the understanding that the publisher is not engaged in rendering professional services If professional advice or other expert assistance is required, the services of a competent professional should be sought The publisher and the author make no representations or warranties with respect to the accuracy or completeness of the contents of this work and specifically disclaim all warranties, including without limitation any implied warranties of fitness for a particular purpose This work is sold with the understanding that the publisher is not engaged in rendering professional services The advice and strategies contained herein may not be suitable for every situation In view of ongoing research, equipment modifications, changes in governmental regulations, and the constant flow of information relating to the use of experimental reagents, equipment, and devices, the reader is urged to review and evaluate the information provided in the package insert or instructions for each chemical, piece of equipment, reagent, or device for, among other things, any changes in the instructions or indication of usage and for added warnings and precautions The fact that an organization or Website is referred to in this work as a citation and/or a potential source of further information does not mean that the author or the publisher endorses the information the organization or Website may provide or recommendations it may make Further, readers should be aware that Internet Websites listed in this work may have changed or disappeared between when this work was written and when it is read No warranty may be created or extended by any promotional statements for this work Neither the publisher nor the author shall be liable for any damages arising herefrom Library of Congress Cataloging-in-Publication Data Szacilowski, Konrad Infochemistry : information processing at the nanoscale / Konrad Szacilowski p cm Includes bibliographical references and index ISBN 978-0-470-71072-2 (hardback) Molecular computers I Title QA76.887.S93 2012 6200 5—dc23 2012007002 A catalogue record for this book is available from the British Library HB ISBN: 9780470710722 Set in 10/12pt Times Roman by Thomson Digital, Noida, India For Bela, Maria and Marek, with love Contents Preface Acknowledgements xi xiii Introduction to the Theory of Information 1.1 Introduction 1.2 Definition and Properties of Information 1.3 Principles of Boolean Algebra 1.4 Digital Information Processing and Logic Gates 1.4.1 Simple Logic Gates 1.4.2 Concatenated Logic Circuits 1.4.3 Sequential Logic Circuits 1.5 Ternary and Higher Logic Calculi 1.6 Irreversible vs Reversible Logic 1.7 Quantum Logic References 1 7 10 11 14 16 18 20 Physical and Technological Limits of Classical Electronics 2.1 Introduction 2.2 Fundamental Limitations of Information Processing 2.3 Technological Limits of Miniaturization References 23 23 24 27 34 Changing the Paradigm: Towards Computation with Molecules References 37 53 Low-Dimensional Metals and Semiconductors 4.1 Dimensionality and Morphology of Nanostructures 4.2 Electrical and Optical Properties of Nanoobjects and Nanostructures 4.2.1 Metals 4.2.2 Semiconductors 4.3 Molecular Scale Engineering of Semiconducting Surfaces 4.3.1 Semiconductor–Molecule Interactions 4.3.2 Electronic Coupling between Semiconducting Surfaces and Adsorbates References 63 63 70 70 84 96 100 103 109 viii Contents Carbon Nanostructures 5.1 Nanoforms of Carbon 5.2 Electronic Structure and Properties of Graphene 5.3 Carbon Nanotubes 5.4 Conjugated and Polyaromatic Systems 5.5 Nanocarbon and Organic Semiconductor Devices References 119 119 120 129 139 149 156 Photoelectrochemical Photocurrent Switching and Related Phenomena 6.1 Photocurrent Generation and Switching in Neat Semiconductors 6.2 Photocurrent Switching in MIM Organic Devices 6.3 Photocurrent Switching in Semiconducting Composites 6.4 Photocurrent Switching in Surface-Modified Semiconductors References 165 165 168 178 181 192 Self-Organization and Self-Assembly in Supramolecular Systems 7.1 Supramolecular Assembly: Towards Molecular Devices 7.2 Self-Assembled Semiconducting Structures 7.3 Self-Assembly at Solid Interfaces 7.4 Controlling Self-Assembly of Nanoparticles 7.5 Self-Assembly and Molecular Electronics References 199 199 201 210 212 215 219 Molecular-Scale Electronics 8.1 Electron Transfer and Molecular Junctions 8.2 Nanoscale Electromagnetism 8.3 Molecular Rectifiers References 225 225 232 238 246 Molecular Logic Gates 9.1 Introduction 9.2 Chemically Driven Logic Gates 9.2.1 OR Gates 9.2.2 AND Gates 9.2.3 XOR Gates 9.2.4 INH Gates 9.2.5 IMP Gates 9.2.6 Inverted Logic Gates (NOR, NAND, XNOR) 9.2.7 Behind Classical Boolean Scheme-Ternary Logic and Feynman Gate 9.3 All-Optical Logic Gates 9.4 Electrochemical Logic Systems References 249 249 249 252 255 267 272 281 283 289 298 307 315 Contents ix 10 Molecular Computing Systems 10.1 Introduction 10.2 Reconfigurable and Superimposed Molecular Logic Devices 10.3 Concatenated Chemical Logic Systems 10.4 Molecular-Scale Digital Communication 10.4.1 Multiplexers and Demultiplexers 10.4.2 Encoders and Decoders 10.4.3 Molecular-Scale Signal Amplification 10.5 Molecular Arithmetics: Adders and Subtractors 10.5.1 Molecular-Scale Half-Adders 10.5.2 Molecular-Scale Half-Subtractors 10.5.3 Half-Adders/Half-Subtractors 10.5.4 Full Adders and Full Subtractors: Towards Molecular Processors 10.6 Molecular-Scale Security Systems 10.7 Noise and Error Propagation in Concatenated Systems References 323 323 323 337 353 354 355 359 363 363 372 381 11 Bioinspired and Biomimetic Logic Devices 11.1 Information Processing in Natural Systems 11.2 Protein-Based Digital Systems 11.2.1 Enzymes as Information Processing Molecules 11.2.2 Enzymes as Information Carriers 11.3 Binary Logic Devices based on Nucleic Acids 11.4 Logic Devices Based on Whole Organisms References 405 405 408 409 428 430 445 450 12 Concluding Remarks and Future Prospects References 457 458 Index 461 382 386 396 398 Preface: Why “Infochemistry”? ‘It is a very sad thing that nowadays there is so little useless information.’ Oscar Wilde For many people, information processing using molecules seems a kind of science fiction It is hard to imagine fancy netbooks, palmtops and other smart electronic gadgets replaced by jars of snot-like liquid or other gebuzina1 On the other hand each of us carry the most powerful information processing “device” that can be found anywhere: the brain At this moment and in any foreseeable future, mimicking our brains with any artificial systems of any kind seems impossible However, we should keep trying to force molecular systems to compute While we will not be able to build powerful systems, all this effort can serendipitously yield some other valuable results and technologies And even if not, the combination of chemistry and information theory paves an exciting path to follow There is a quote attributed to Richard P Feyman saying:“Physics is like sex Sure, it may give some practical results, but that’s not why we it” With infochemistry is it exactly the same! When approximately half of the manuscript was ready I realized that it was going to be almost a “useless” book For most chemists it may be hard to follow due to the large amount of electronics content, while for electronic engineers there is far too much chemistry in it And both fields, along with solid-state physics, are treated rather superficially, but are spiced with a handful of heavy mathematics and a couple of buckets of weird organic structures But then I found that rather optimistic sentence by Oscar Wilde which motivated me to complete this work This book treats the interface between chemistry and information sciences There are other books which can be located in this field, including my favourites Ideas of Quantum Chemistry by Lucjan Piela and Information Theory of Molecular Systems by Roman F Nalewajski In my book I have tried to show how diverse properties of chemical systems can be used for the implementation of Boolean algebraic operations The book can be divided into three main sections The first section (Chapters 1–3) explores the basic (Slovak) unidentified disgusting semi-liquid substance of unpleasant smell, swill xii Preface principles of the theory of information, the physical and technological limits of semiconductor-based electronics and some alternative approaches to digital computing The next section (Chapters 4–8) is intended to show how the properties of materials commonly used in classical electronics are modified at the nanoscale, what happens at the molecule/semiconductor interface and how these phenomena can be used for information processing purposes Finally, the last section (Chapters 9–11) are (I hope) a comprehensive review of almost all molecular logic systems described in the chemical literature from 1993 (the seminal Nature paper by Amilra Prasanna de Silva) to November 2011, when my “ ”2 was over An original title of a novel by Aleksey Nikolayevich Tolstoy The title was translated as “The Road to Calvary”, but its literal meaning is rather “walking through torments” Acknowledgements I would like to thank my wife Bela and kids Maria and Marek for their patience, help and support during the preparation of this manuscript Without their love and understanding this book could not have been written I would also like to express my gratitude to my teachers and mentors for their efforts and devotion First of all I should mention my grandfather Stefan Polus, who showed me the wonderful world of electronics, my PhD supervisor Professor Zofia Stasicka, who introduced me to the realm of inorganic photochemistry and my postdoctoral mentor, Professor John F Endicott who taught me careful data analysis and skepticism Large parts of this book were written at The Faculty of Non-Ferrous Metals, AGH University of Science and Technology Therefore I address my thanks to the Dean of the Faculty, Professor Krzysztof Fitzner for his patience and support This book could not have been written without financial support Most of the manuscript was prepared with support from AGH-UST within contract No 11.11.180.509/11 Many results presented in this book were obtained within several research projects funded by The Polish Ministry of Science and Higher Education (grants Nos 1609/B/H03/2009/ 36, 0117/B/H03/2010/38 and PB1283/T09/2005/29), The National Centre for Research and Development (grant No NCBiR/ENIAC-2009-1/1/2010), The European Nanoelectronics Initiative Advisory Council JU ENIAC (Project MERCURE, contract No 120122) and The European Regional Development Fund under the Innovative Economy Operational Programme (grant No 01.01.02-00-015/09-00), both at The Faculty of Chemistry, Jagiellonian University and The Faculty of Non-Ferrous Metals, AGH University of Science and Technology Last but not least I would like to thank my copy-editor Jo Tyszka and the Wiley editorial and production team: Rebecca Stubbs, Emma Strickland, Sarah Tilley, Richard Davies, Tanushree Mathur and Abhishan Sharma Thank you! 462 Index Aviram–Ratner molecular rectifiers 238–46 azacrown cation receptors 255–6 azobenzenes 279–80, 284–5, 408–9 azulene 370–1, 384–6 backscattering 122 bacteriorhopsodin 304–6 band bending (BB) 98, 100, 103 bandgap energy carbon nanostructures 120, 125, 127–8, 144–5 metallic particles 74 photoelectrochemical photocurrent switching 184–5 semiconductor devices 74, 93, 104 technological limits of miniaturization 28 bandgap engineering 92 band-pair microelectrodes 310–11 barium 277 bathochromic shifts biomimetic logic devices 417 molecular computing systems 364, 372–3, 393 molecular logic gates 251, 280 semiconductor devices 83–4 BB see band bending benzothiazoles 332–3 Berry phases 121–2, 123 Bessel functions 92 biindalylidene 133–4 bijective mapping 17 bilayer graphenes 125–8 binaphthalene (BN) 290–1 binary comparators 11, 383–4 binary decoders 355–9 binary encoders 355–9 binary full adders biomimetic logic devices 438–40 information theory 11–13 molecular computing systems 382–6 binary full subtractors 11–13, 382–6 binary half-adders biomimetic logic devices 415, 432 information theory 9, 10–11 molecular computing systems 363–72, 381–2 photoelectrochemical photocurrent switching 191–2 binary half-subtractors 10–11, 372–82 binary logic 3–14 binary switches 3–4 binary-to-ternary converters 14–15, 302 binuclear complexes 346–7 biocatalytic cascades 417–19, 424–5 biochips 24 biofuel cells 424, 447–8 biomedical sensing 52 biomimetic logic devices 405–56 electrochemical logic systems 419–22 enzymes as information carriers 428–9 enzymes as information processors 409–28 information processing in natural systems 405–7 molecular electronics 238 molecular information processing 39, 51–2 molecular logic gates 299–300 nucleic acids 430–44 protein-based digital systems 408–29 semiconductor devices 99 semiconductors 426–8 whole organism logic devices 445–50 biomolecules 99, 170 bipolaron 232 2,20 -bipyridyl-3,30 -diol 375 bis(dimethyldihydropyrene) 289 bismuth vanadate 180 bis(phenylethynyl)anthracene (BPEA) 361–3 bistable behaviour 40–1 Bloch spheres 18–19 Bloch states 105 Bloch theorem 123–4, 130–1 BN see binaphthalene BODIPY-based fluorescent sensors 253–4, 262–3, 277, 280, 282, 337 Bohr radii 92–3 Boolean algebra/logic biomimetic logic devices 405–6 future prospects 458 molecular electronics 245–6 molecular information processing 38–9, 42–3, 45–8 molecular logic gates 251–2, 289 principles 4–7 Bose–Einstein statistics 86 bottom-gate–bottom-contact configuration 150 bottom-gate–top-contact configuration 150, 190 BPEA see bis(phenylethynyl)anthracene Brillouin zones 120–1, 124, 127, 130 Index Brus model 93–4 bulk molecular electronic devices 42–3 C-NOT gates 16–18, 297–8 c/q see quantum-to-classical cadmium complexation 280, 324–6, 364 cadmium selenide 94–6, 178, 180, 264 cadmium sulfide 95, 167–8, 180, 191 cadmium telluride 95, 178, 180 calcium 256, 260, 263, 271, 331 calix[4]arenes 277–9, 285, 288, 324, 391–2 calix[4]pyrrole-coumarins 272–3 capacitance carbon nanostructures 151 molecular electronics 233 photoelectrochemical photocurrent switching 192 self-assembly processes 211–12 semiconductor devices 72–4 technological limits of miniaturization 29–30 capped nanotubes 130 carbazole chromophores 174–5 carbazole-induced photocleavage 435–6 carbon nanostructures 119–64 applications 131, 149 carbon nanotubes 120, 129–38, 150–5, 232–8 chirality 123, 129–31 conjugated and polyaromatic systems 120, 139–56 covalent modifications 134–6 electronic structure and properties 120–31, 138 electrostatic doping 155–6 graphenes 119, 120–9, 156, 203–5 logic gates 150–6 metallic conductivity 130–1, 138 molecular electronics 232–8 nanoforms of carbon 119–20 non-covalent modifications 135–8 organic semiconductors 139–41, 146–56 self-assembly processes 203–5, 207 semiconducting behaviour 130–1, 138 semiconductor devices 149–56 see also fullerenes carbon nanotubes (CNT) 120, 129–38, 150–5, 232–8 carminate-modified titanium dioxide 187–8 CC-NOT gates 16–17 463 CD see circular dichroism cell membranes 37–8 cellular automata 10 cerium 328, 381–2 chalcones 293–4, 298–300 charge-carrier mobility 207 charge migration 88–9 charge-transfer excitons 149 charging energies 73 chemical amplification 360–1 chemical half-adders 369–71 chemical sensors carbon nanostructures 133, 137–8 molecular computing systems 329, 341–2, 391–2 molecular information processing 42–3 see also chemically driven logic gates chemically driven logic gates 249–98 AND gates 255–66 INH gates 270, 272–81 inverted logic gates 283–8 NAND gates 286–7 NOR gates 261, 283–6 OR gates 252–5 ternary logic and Feynman gates 289–98 XNOR gates 268, 271, 288 XOR gates 267–72, 275 chemiluminescence detectors 170–1 chirality 123, 129–31 chloride 272 chlorins 202 choline oxidase (ChOx) 411–13 circular dichroism (CD) 290–1 cis–trans isomerization 97, 293–6, 334 Clar structures 146 classical-to-quantum (c/q) conversions 244–5 CMOL architecture 218–19 CMOS see complementary-symmetry metal oxide semiconductors CMOS logic 152 CNT see carbon nanotubes cobalt 325, 329 collision computing 449 colorimetric pH indicators 46 colossal magnetoresistance 44, 49–50 combinatorial logic circuits 11–12 commutativity comparators see binary comparators complement see NOT function/gates 464 Index complementary-symmetry metal oxide semiconductors (CMOS) 152, 218–19 concatenability 47–8 concatenated logic systems 10–11, 337–53, 396–8, 411–13 conjugated carbon nanostructures 120, 139–56 conjunction see AND function/gates connecting bridges 217, 225–7 coolants 33–4 copper molecular computing systems 324–30, 332, 335–7, 342, 376, 378, 382, 390–4 molecular logic gates 260, 274–8, 283–6 copper iodide composites 180 copper oxide composites 180 copper-phthalocyanine–fullerene heterojunctions 172 core–shell nanoparticles 70, 264, 442 core–shell nanostructures 71, 93–6 coronenes 146, 203, 205–7 cosmic rays 29 Coulomb blockade effects 71, 73–4, 76–7 Coulomb gaps 73, 76 Coulomb staircases 73–4 coumarins 266, 329 creatine kinase (CT) 429 Creutz–Brunschwig–Sutin model 103–4, 107, 183 cross-wire electrochemical transistors 314 crosslinking 435–6 crosstalk 24 crown ethers molecular computing systems 333–4, 342, 392 molecular logic gates 255–8, 261–4, 267–8, 273, 282–3, 286–7, 291–2 cryptands 252–3 cryptography 386 CT see creatine kinase cucurbit[7]uril 260–1 cumulenes 119 cyanoanthryl fluorophores 255–6 cycloaddition reactions 134, 136 cyclodextrins 260, 281, 369 damping processes 78–81 dansyl chromophores 285 Davydov splitting 148 DBD see DNA-binding domains de Broglie wavelengths 71–2 De Morgan duality Debye frequency 88 Debye temperature 88 decoders 355–9 degenerate four wave mixing (DFWM) 306 Dember effect 90–1, 165 demultiplexers 49, 187, 311, 354–5 dendritic wires 218 density functional theory (DFT) 183 density of states calculations 208, 231 deoxyribonucleic acid (DNA) 202, 406–7, 430–44 deoxyribozymes 437–40 depletion layer thickness 29 Deutsch quantum gates 20 device cooling 24, 31–4 dexamethasone 445–7 DFT see density functional theory DFWM see degenerate four wave mixing diamontoids 119 diaphorase (DIA) 419 dielectric functions 80–1 digital information processing 7–14 digital noise 397–8 dihydroazulene 289–90 dihydroindolizine 366–7 dimensionality bulk properties and dispersion 64–6, 76 chemical composition 67–8 classification of nano-objects and nanomaterials 66–9, 96 growth mechanisms and conditions 68–70 morphology of nanostructures 63–70 self-assembly processes 213–14 dimethylaniline 289–90 diode–diode logic 241–2 diphenylaniline 292 diphenylpyridines 333–4 dipicolylamine–bipyridine 364 dipicolylamine receptors 263 Dirac equation 122, 126 Dirac points 120–2, 124 direct-gap semiconductors 85–7, 88 DISABLED OR gates 326–7 discotic columnar phases 205–8 discrete dipole approximation 82 disjunction see OR function/gates disordered conductors 228–9 Index distributivity dithienylethene 356, 361–3, 389–90 ditopic receptors 255, 257, 263, 273 DNA see deoxyribonucleic acid DNA-binding domains (DBD) 445–7 donor–spacer–acceptor architectures 168–9, 225–7, 251 doping inhomogeneity 24 double-decker complexes 209–10 double-gate MOSFET (FINFET) transistors 30–1 double tunnel junctions 74 double-walled carbon nanotubes (DWCNT) 138 Drude–Sommerfeld model 78–80 dual action devices 257 dumbbell nanoparticles 70 DWCNT see double-walled carbon nanotubes dynamic self-assembly processes 200 ECL see electrogenerated chemiluminescence edge-driven paradigm 215–19 EET see electronic energy transfer Einstein–Podolski–Rosen states 19 Einstein’s special theory of relativity 2, 23, 25–6, 121 EIS see electrolyte–insulator–semiconductor structures electric logic devices 50–1 electrical permittivity 28 electrochemical half-adders 369–71 electrochemical logic systems 290–3, 307–15, 419–22 electrochemical transistors 313–15 electrogenerated chemiluminescence (ECL) 307–10 electrolyte–insulator–semiconductor structures (EIS) 426–7 electromagnetism 232–8, 246 electron hopping phenomena 200–1, 207, 227, 230 electron tunnelling information processing limitations 24 molecular electronics 227, 229–30, 237, 239 semiconductor devices 71–2 technological limits of miniaturization 31–2 electronic amplification 360–1 electronic coupling 97–8, 103–9 465 electronic energy transfer (EET) 249–50 electrostatic doping 155–6 ELISA see enzyme-linked immunosorbent assay ENABLED NOR gates 325–6 ENABLED OR gates 329 encoders 355–9 energy-level broadening 230–1 enol–keto isomerism 265 entropy 2–3, 26 enzymatic devices 397–8 enzyme-based digital systems 408, 409–29 enzyme-linked immunosorbent assay (ELISA) 425–6 error propagation 396–8 ESIPT see excited state intramolecular proton transfer ethidium bromide 435 ethynylene bridges 209–10 europium complexes 268–9, 274–5, 327 excited state intramolecular proton transfer (ESIPT) pathway 265 extrinsic photoconductivity 89–90 FAD see flavin adenine dinucleotide FALSE values 14–15 FAN-OUT gates 10 FDH see formaldehyde dehydrogenase feedback loops 11–12, 341 Fermi–Dirac distribution 80–1, 228 Fermi energy molecular electronics 234 semiconductor devices 74–5, 101, 104, 108 Fermi levels carbon nanostructures 120, 122, 124, 147 molecular electronics 227–8, 240 semiconductor devices 97, 100–1, 108 Fermi potential 166 Fermi velocity 122, 126 Fermi wavenumber 75 ferrocenes molecular computing systems 346–7 molecular logic gates 273–4 photoelectrochemical photocurrent switching 169–70, 174 self-assembly processes 203, 205–7 ferrocenylboronic acid 186–7 Feynman gates 16–18, 297–8 Feynman quantum gate notation 16 466 Index field-effect transistors (FET) biomimetic logic devices 426 carbon nanostructures 131–2, 136–8, 140, 144, 146–7, 150–4 molecular electronics 242–4 performance characteristics 30–1 photoelectrochemical photocurrent switching 190–1 FINFET see double-gate MOSFET flavanones 293–4 flavin adenine dinucleotide (FAD) 421 flavylium-based switches 293–7, 298–300 flip-flops 13, 395–6, 419–20 fluorenones 284 fluorescein hydrazones 276 fluoresceins biomimetic logic devices 431–4 molecular computing systems 364, 383, 387–9 fluoride 257, 273, 288, 292–3, 392–3 fluorophores 48 flux 234–5 Fokker–Planck equation formaldehyde dehydrogenase (FDH) 409–11 F€orster resonant energy transfer (FRET) molecular computing systems 336, 364, 370–1, 387 molecular logic gates 270, 277 self-assembly processes 202 semiconductor devices 98 four-input keypad locks 386–7 four-input logic devices 326 four-state switches 334, 346–7 Fredkin gates 10, 16–18 free electron model 80 Frenkel excitons 87, 148–9 frequency modulation 361–3 FRET see F€orster resonant energy transfer Fukui function 101–2 fulgimide 356–7, 389–90 full adders see binary full adders full subtractors see binary full subtractors fullerenes 119, 120, 134, 150 molecular computing systems 366 molecular logic gates 259 photoelectrochemical photocurrent switching 172, 176–7 Galperin–Nitzan model 103 gap junction channels 41–2 GDH see glucose dehydrogenase Gedankenmolek€ ul rectifiers 238–46 gel photodiode logic devices 175 giant magnetoresistance (GMR) 44 global Coulomb threshold 77 glucose dehydrogenase (GDH) 411–13, 415, 419–20, 423–5 glucose oxidase (GOx) 409–11, 413–15, 417–19, 421–4, 427–8 GMR see giant magnetoresistance G€ odel theorem 45 gold photoelectrodes 174–6 GOx see glucose oxidase graphenes 119, 120–9, 156, 203–5 green fluorescent protein (GFP) 408–9 GroEL chaperone protein 408–9 gustation 39 H-aggregates 148, 203 Hadamard gates 20 half-adders see binary half-adders half-subtractors see binary half-subtractors Halperin–Lax tails 86–7 heat dissipation 24, 31–4 Heisenberg limit 33 Heisenberg’s uncertainty principle 23, 25, 32 HEPES see 4-(2-hydroxyethyl)-1piperazineethanesulfonate herringbone arrangements 140–3 heteroacenes 143, 145 heterosynaptic interactions 237–8 hexacyanoferrate composites 181–7 hexa-peri-hexabenzocoronene 203, 205–7 hierarchical temporal memory (HTM) networks 51 high impedance states (HiZ) 16 highly oriented pyrolytic graphite (HOPG) 207 Hill function 40–1 HiZ see high impedance states homoserine lactones 39–40, 448–9 homosynaptic interactions 237–8 HOPG see highly oriented pyrolytic graphite hopping phenomena 200–1, 207, 227, 230 horseradish peroxidase (HRP) 411, 415, 417–20, 425–6 host–guest interactions 214 HRP see horseradish peroxidase HTM see hierarchical temporal memory hybrid molecular electronic devices 42–3 Index hydrazones 276 hydrogen bonding molecular logic gates 281, 287 self-assembly processes 202–3, 208–9, 214–15 hydroxybenzyl linkers 255 4-(2-hydroxyethyl)-1-piperazineethanesulfonate (HEPES) 254 hydroxyperylenebisimides 270 hypsochromic shifts molecular computing systems 332–6, 341–2, 378 molecular logic gates 251, 263, 272 semiconductor devices 84 hysteresis carbon nanostructures 156 molecular electronics 237 molecular information processing 40–1 ICT see intramolecular charge transfer idempotence 6–7 identity bits 11 identity function mapping 397 ILCT see intraligand charge transfer imidazole quenching 258, 260, 269 immunoglobulins 425–6 IMP gates biomimetic logic devices 443 information theory 8–9 molecular computing systems 335 molecular logic gates 281–3 impedance 232–3 indirect-gap semiconductors 85–6, 88 indium arsenide 94–5 indium phosphide 95 indium tin oxide (ITO) 169, 174, 180, 189–91, 307 indium–titanium-dioxide composites 181 infomolecules 39–42 information carriers 428–9 information processing characteristic length scales 202 digital 7–14 fundamental limitations 24–7 future prospects 457–8 molecular 37–61 molecular electronics 244–5 natural systems 405–7, 409–28 pathways in living cells 37–8 self-assembly processes 202 467 information theory 1–21 binary switches 3–4 Boolean algebra/logic 4–7 concatenated logic circuits 10–11 definitions 2–4 digital information processing 7–14 future prospects 458 irreversible and reversible logic 16–18 logic gates 7–14 quantum logic 18–20 sequential logic circuits 11–14 ternary and higher logic calculi 14–16 INH gates biomimetic logic devices 438–40, 442–3 information theory 8–9 molecular computing systems 325–6, 329–37, 344–5, 348, 373–9, 381–2 molecular logic gates 270, 272–81, 303 photoelectrochemical photocurrent switching 185 insulating particles 65–6, 74–7, 214–15 integrated circuitry 199 interband excitations 79 interface damping 79 intraband excitations 79 intraligand charge transfer (ILCT) 347 intramolecular charge transfer (ICT) molecular computing systems 332–4, 374–5, 378–9 molecular logic gates 249–50, 251–2, 262–3, 285 intramolecular electronic delocalization 209 intrinsic photoconductivity 88–90 invertase (INV) 413, 417–18, 424–5, 427–8 inverters see NOT gates Ioffe–Regel criterion 75–6 ion-selective field effect transistors (ISFET) 426–7 ionic liquids 315 Iowa Black QR quencher 430–1 iron biomimetic logic devices 417 molecular computing systems 327, 330, 342, 370, 387–9 molecular logic gates 265–6, 288 see also ferrocenes irreversible logic 16–18 ISFET see ion-selective field effect transistors isolated nanorods 71 isoquinoline N-oxide 273, 355 468 Index isotropic growth 69 ITO see indium tin oxide J-aggregates 148, 203 Josephson junctions 24 Joule heating 153–4 Kasha’s rule 372 keto–enol isomerism 265 keypad locks 386–95, 425–6 kinetic inductance 233–4 Kubo gap 75 Kunh equation 144 lactate oxidase 417–20 lactose dehydrogenase (LDH) 429 Landau levels 124–5, 127 Landauer formula 4, 228 Langmuir–Blodgett films 169, 172, 174, 241 LAPS see light-addressable potentiometric sensors latches 13, 395–6, 419–20 latency 24, 30 LDH see lactose dehydrogenase lead 324, 342, 443 lead sulfide 167 leakage currents 31 LED see light emitting diodes ligand-to-ligand charge transfer (LLCT) 347 ligand-to-metal charge transfer (LMCT) 347 light emitting diodes (LED) 185–6 light-addressable potentiometric sensors (LAPS) 426–7 linear dichroism 261–2 linkers 214–15, 255 lipid bilayers 37–8 liquid crystalline phases 207–8 LLCT see ligand-to-ligand charge transfer LMCT see ligand-to-metal charge transfer local softness 101 logic gates biomimetic logic devices 407, 409–17, 422–44 carbon nanostructures 150–6 concatenated logic circuits 10–11 information theory 7–14 molecular computing systems 324–8 molecular electronics 241–3, 245–6 photoelectrochemical photocurrent switching 168–9, 173–4 self-assembly processes 216–18 sequential logic circuits 11–14 simple 7–10 symbols, truth tables and Venn diagrams 7–10 see also individual gate types; molecular logic gates longitudinal plasmons 79–80 Lorenzian density of states 231 Lorenzian envelopes 105 low-dimensional metals bulk properties and dispersion 63–6, 76 chemical composition 67–8 classification of nano-objects and nanomaterials 66–9 growth mechanisms and conditions 68–70 morphology of nanostructures 63–70 luminescence quenching molecular computing systems 324–8, 336, 377, 391–4 molecular logic gates 263, 278, 297–8 Lycurgus cup 63 magnesium 266, 334 magnetic inductance 233–4 magnetic phenomena 50, 232–8, 246 magnetic tunnel effect 44 majority bits 11 MAJORITY gates 10 MAYA automatons 440–1 medical applications biomimetic logic devices 428–9, 442 future prospects 458 molecular logic gates 254–5 memory cells 45–6 memory functions biomimetic logic devices 419 information theory 11–12 molecular computing systems 340–1 molecular electronics 235–8 self-assembly processes 208, 216, 217–18 memresistance 235–8 mercaptosuccinic acid 348–51 mercury biomimetic logic devices 442 molecular computing systems 326, 336, 345, 392, 394 molecular logic gates 263, 277, 285 merocyanines 368, 370, 395, 416 Index metal–insulator transitions 75–7 metal–insulator–metal (MIM) devices 167, 168–78 metal–ligand affinities 203, 214 metal–ligand charge transfer (MLCT) 347 metal–metal charge transfer (MMCT) 184–5 metal-oxide semiconductor field-effect transistors (MOSFET) carbon nanostructures 132, 140 performance characteristics 30–1 metal–semiconductor junctions 98, 102 metallic conductivity 130–1, 138 metallic particles molecular electronics 228 self-assembly processes 210, 214–17 semiconductor devices 65–6, 70–84 metalloporphyrins 202–4, 209–10 methotrexate 445–7 methoxybenzodeazaadenine 435–6 methoxypyridylthiazoles 326–8 8-methoxyquinoline 355 microbial fuel cells 447–8 microfluidic devices 170–2 microperoxidase-11 (MP-11) 411–14, 421–2 Mie theory 80–2 MIM see metal–insulator–metal miniaturization, technological limits 27–34 mixed dimensionality 96 MLCT see metal–ligand charge transfer MMCT see metal–metal charge transfer molecular amplifiers 359–63, 413–14 molecular cables 207 molecular clusters 65–6, 71 molecular computing systems 323–403 adders and subtractors 363–86 biomimetic logic devices 442, 449–50 concatenated logic systems 337–53, 396–8 encoders and decoders 355–9 future prospects 457–8 molecular digital communication 353–63 multiplexers and demultiplexers 49, 187, 311, 354–5 noise and error propagation 396–8 reconfigurable logic devices 323–37 security systems 386–96 signal amplification 359–63, 413–14 superimposed logic devices 324, 332–7 molecular digital communication 353–63 encoders and decoders 355–9 469 multiplexers and demultiplexers 49, 187, 311, 354–5 signal amplification 359–63, 413–14 molecular diodes 226, 238–46 molecular electronics 225–48 electron transfer and molecular junctions 225–32 molecular information processing 42–3, 49 molecular rectifiers 226, 238–46 nanoscale electromagnetism 232–8, 246 self-assembly processes 215–19 molecular information processing 37–61 biomimesis and self-assembly 39, 51–2 Boolean algebra/logic 38–9, 42–3, 45–8 classification 48–9 molecular switches and logic devices 42–7, 50–1 nanomachines 40–2 non-linear transfer characteristics 47–8 pathways in living cells 37–8 molecular junctions 225–32, 237 molecular linkers 214–15, 255 molecular logic devices carbon nanostructures 132 future prospects 458 molecular information processing 42–7, 50–1 photoelectrochemical photocurrent switching 188 see also molecular computing systems molecular logic gates 152, 249–322 all-optical logic gates 298–307 AND gates 255–66, 303–4, 306–11 chemically driven logic gates 249–98 electrochemical logic systems 290–3, 307–15 IMP gates 281–3 INH gates 270, 272–81, 303 NAND gates 286–7, 306, 310, 312 NOR gates 261, 283–6, 297, 300, 303, 306, 308–10, 312 OR gates 252–5, 306–7, 310 ternary logic and Feynman gates 289–98 XNOR gates 268, 271, 288 XOR gates 267–72, 275, 303 molecular oxygen 274–5, 281 molecular recognition 39 molecular rectifiers 168–9, 226, 238–46 molecular switches 42, 44–6, 334, 346–7 monostable switches 46 470 Index Moore’s Law 23 3-morpholinopropanesulfonate (MOPS) 253–4 morphology of nanostructures 63–70 MOSFET see metal-oxide semiconductor fieldeffect transistors M€ossbauer shifts 66 Mott metal–insulator transitions 76–7 Mott–Wannier excitons 92 MP-11 see microperoxidase-11 Mulliken electronegativity coefficients 100 Mulliken hardness 72 multi-functional junctions 226 multilayer structures 95–6, 129 multi-photon photophysical processes 384 multiplexers 49, 354–5 multi-state molecular switches 251, 289–98 multi-walled carbon nanotubes (MWCNT) 134 mutual suppression 407 MWCNT see multi-walled carbon nanotubes n-type semiconductors bandgap energy 90 carbon nanostructures 121, 124, 132, 141, 147–8, 151–2 photoelectrochemical photocurrent switching 178–80, 190–1 semiconductor–molecule interactions 103–5 NAD/NADH see nicotinamide adenine dinucleotide NAND gates biomimetic logic devices 413, 417, 434–5 carbon nanostructures 150–1, 153, 155–6 information theory 7, 8–9, 13 molecular computing systems 327, 338–41, 351–3 molecular information processing 48 molecular logic gates 286–7, 306, 310, 312 nanocell devices 217–18 nanoflakes 128–9, 203–5 nanomachines 40–2 nanomaterials 66–7, 96 nano-objects dimensionality 66–9 electrical and optical properties 70–96 nanoparticles biomimetic logic devices 417–18, 427–8, 442 molecular computing systems 330 photoelectrochemical photocurrent switching 181, 190–2 self-assembly processes 200, 210–19 semiconductor devices 71–9, 97–9, 102–3 nanoribbons 125 nanorod–nanoparticle hybrids 71 nanorods 67, 71 nanoscale electromagnetism 232–8, 246 nanostructures electrical and optical properties 70–96 low-dimensional metals 63–70 morphology 63–70 self-assembly processes 200, 210–11 semiconductor devices 63–70, 84 see also carbon nanostructures nanotube–nanoparticle hybrids 135 nanotubes 67 see also carbon nanotubes nanowires 67, 219 naphthalimides 276, 285–6, 395–6 naphthoperylenebisimides 270 narrow band-gap semiconductors 94–6 Nd:YAG lasers 365–7 neural plasticity 238 neurons 1, 199–200, 218–19, 299–300 neurotransmitters 47, 52 neutral elements 6–7 neutrinos 121 Newns–Anderson model 105 nickel 278–9, 324–5, 329 nickel–titanium-dioxide composites 181–7 nicotinamide adenine dinucleotide (NAD/ NADH) 409–11, 413–15, 423–5, 428–9 nitrobenzoate 287 nitrosylpentacyanoferrate complex 348–51 nitrosyl tetrafluoroborate 327 nitroxide quenching 258 NMR see nuclear magnetic resonance noise propagation 396–8 non-destructive computing see reversible logic non-linear transfer characteristics 47–8, 216–19 non-resonant coherent tunnelling 229–30 NOR gates biomimetic logic devices 410–11, 413, 417, 435 carbon nanostructures 150–1, 153, 155–6 information theory 8–9, 13 molecular computing systems 324–7, 329, 332, 336–7, 344–6, 348 Index molecular information processing 48 molecular logic gates 261, 283–6, 297, 300, 303, 306, 308–10, 312 NOT function 5–6, NOT gates biomimetic logic devices 409, 413–14, 430, 438 carbon nanostructures 150–2, 155–6 information theory 8, 10, 16 molecular computing systems 338–41 molecular information processing 48 molecular logic gates 301, 306, 312 photoelectrochemical photocurrent switching 174 nuclear magnetic resonance (NMR) 27, 50 nuclear spin coupling 50 nucleation processes 69 nucleic acids 430–44 nucleotides 287 occlusion deposition 181 OFET see organic field-effect transistors olfaction 39 oligoacenes 140–6, 149 one-input logic gates 46 one-way suppression 407 onion-like structures 95–6 optical amplification 360–1 optical antenna model 79 optical electron transfer 106–7, 201 optical full adders 384–6 optical half-adders 365–9, 371–3 optical logic gates 298–307 optocouplers 170–2 optoelectronic switches 79 OR function 5–6, 7, 331–2, 336, 344–6 OR gates biomimetic logic devices 407, 410–12, 417, 422–8, 430–5, 444–7 carbon nanostructures 153 information theory 8–10, 13, 15 molecular computing systems 324–8, 338–41, 351–2 molecular electronics 242–3 molecular information processing 48 molecular logic gates 252–5, 306–7, 310 photoelectrochemical photocurrent switching 168–9, 175, 185–6 self-assembly processes 216–17 organic electrochemical transistors 313–14 471 organic field-effect transistors (OFET) carbon nanostructures 140, 144, 147 photoelectrochemical photocurrent switching 190–1 organic semiconductors 139–41, 146–56 osmium complexes 327–8, 359–61, 423 Ostwald ripening 213 oxadiazoles 326 oxidative doping 207 oxygen quenching 274–5, 281 p–p stacking carbon nanostructures 139–43 self-assembly processes 202–3, 208–9, 214 p–n junctions carbon nanostructures 128 molecular electronics 238 photoelectrochemical photocurrent switching 168–9, 178 technological limits of miniaturization 29 p-type semiconductors bandgap energy 90 carbon nanostructures 121, 131–2, 147, 151–2 photoelectrochemical photocurrent switching 178–80, 190–1 semiconductor–molecule interactions 103–5, 108 palladium gates 151 palladium phthalocyanine 175–6 PANI see polyaniline parabolic band approximation 94 parasitic capacitance 151 particle–surface coupling 83–4 PDMS see poly(dimethylsiloxane) PEDOT see poly(3,4-ethylenedioxythiophene) PEPS see photoelectrochemical photocurrent switching peptides 174–5 performance characteristics 23–35 fundamental limitations of information processing 24–7 physical properties of silicon 27–9 technological limits of miniaturization 27–34 perylenebisimides 141 PET see photoinduced electron transfer phenanthridines 284 phenanthrolines 383–4 phenazines 448–9 472 Index pheromones 457 phosphate 258 phosphonate anchors 177 phosphorylation-based logic devices 416 photoactivated switches 133–4, 137–8 photoactive compounds 43 photocells 191 photochromic switches molecular computing systems 365–7, 370 molecular logic gates 289–90, 300–2, 304–5 photoconductivity 88–90 photocurrent generation 90–1, 99 photoelectrochemical logic systems 172–4, 176, 211 photoelectrochemical photocurrent switching (PEPS) 165–97 metal–insulator–metal devices 167, 168–78 neat semiconductors 165–8 semiconducting composites 178–81 semiconductor devices 100 surface-modified semiconductors 181–92 photoelectrodes 172–3, 192 photoinduced charge separation 96 photoinduced electron transfer (PET) molecular computing systems 324–7, 332, 364, 374, 377 molecular logic gates 249–51, 256, 259, 262–4, 269, 275–80, 284–8, 297 photoelectrochemical photocurrent switching 175 self-assembly processes 201 semiconductor devices 103, 106 photoisomerization carbon nanostructures 133–4 molecular computing systems 334, 337–41, 344, 361–2, 367–9, 395 molecular logic gates 293–6, 305–6 semiconductor devices 97 photomodulation 361–3 photosensitization biomimetic logic devices 435–6 photoelectrochemical photocurrent switching 188–9 self-assembly processes 203–5 semiconductor devices 103–7 photovoltaics 96–7, 180, 187 Physarum polycefalum 449–50 plasmodium 449–50 plasmon resonance 77–83, 179, 417–18 platinum–iron binuclear complexes 346–7 polyacenes 140–6 polyamines 377 polyaniline (PANI) 237 polyaromatic carbon nanostructures 120, 139–56 polybithiophenes 180–1 polycyclic aromatic hydrocarbons 139, 144–6, 201 poly(dimethylsiloxane) (PDMS) 307 poly(3,4-ethylenedioxythiophene) (PEDOT) 312–15 polymer-brush-modified electrodes 422–3 poly(styrene sulfonic acid) (PSS) 312–15 polythiophenes 180–1 poly(4-vinylpyridine) 422–5 polyynes 119 porphyrins molecular computing systems 365–7, 370–3, 389–90 molecular logic gates 261, 303 self-assembly processes 202–4, 209–10 potassium biomimetic logic devices 443 molecular computing systems 392 molecular logic gates 257, 273, 277–8 pragmatic level of information prepositional calculus 4–5 prodrugs 254–5 proline 266 protein-based digital systems 408–29 protein synthesis 406–7 proton acceptors 255–6 Prussian blue–titanium dioxide nanocomposites 187 Pseudomonas aeruginosa 446–9 pseudorotaxanes 267–8, 379–80 pseudospin 123 PSS see poly(styrene sulfonic acid) push–pull systems 251, 271, 377–8 pyrazolones 279 pyrenes molecular computing systems 364, 378–9, 387–9 molecular logic gates 277–8, 286 photoelectrochemical photocurrent switching 169–70 pyrophosphate 280 q/c see quantum-to-classical Index QED see quantum electrodynamics quantum computing 10, 23, 27, 50 quantum confinement 92–3 quantum dots (QD) molecular electronics 226 molecular logic gates 264 molecular scale engineering 96 photoelectrochemical photocurrent switching 167 quantum electrodynamics (QED) 123 quantum entanglement quantum Hall effect 124–5, 127 quantum logic 18–20 quantum mechanics 122, 130–1, 244–5 quantum size effects 28–9, 92, 102–3 quantum tunnelling 227 quantum wells (QW) 96 quantum-to-classical (q/c) conversions 244–5 qubits 18–19, 244 quinolines 39–40, 375 quorum sensing 39–40, 448, 457 race conditions 24 radiationless damping 78–9 radiative damping 78 radical coupling processes 134–5 RC loops 29–30 reaction–diffusion phenomena 405 reconfigurable logic devices 254, 323–37 rectifiers 168–9, 226, 238–46 redox potential 97–8 redox systems biomimetic logic devices 424, 434 molecular computing systems 327–8, 346–7, 357–8, 369–70 molecular electronics 227–8 molecular logic gates 290–1 self-assembly processes 203–5, 211 relativity see special theory of relativity resistance carbon nanostructures 151 molecular electronics 232–8 self-assembly processes 211–12 semiconductor devices 74 technological limits of miniaturization 29–30 resonant coherent tunnelling 229–30 resonant tunnelling diodes (RTD) 216, 217, 241–2 reversible logic 16–18, 297–8 473 rhodamines 347–8, 372–3, 384–6 ribonucleic acid (RNA) 406–7, 430, 437 ring oscillators 151–2 RNA see ribonucleic acid rotaxanes 281–2, 291–3, 369 RTD see resonant tunnelling diodes rubrene 143–4 ruthenium complexes 301–2, 307 ruthenium mixed ligand complexes 269 ruthenium–polypyridyl chromophores molecular computing systems 331, 357–8, 359–61 molecular logic gates 268, 307–9 photoelectrochemical photocurrent switching 174–6, 188–9 Rydberg energy 28, 93 Sakata–Hiramoto–Hashimoto model 103–4 SAM see self-assembled monolayers SC-OFET see single crystal organic field-effect transistors scaling law 77 scattering matrices 245 schizophrenic materials 49–50 Schottky barriers 170, 179, 188–9, 236, 239 Schottky junctions 131, 179 Schottky theory 102 Schr€odinger equation 122–3 Second Law of Thermodynamics security systems 386–96, 425–6 segmented nanorods 71 selenium 178 self-assembled monolayers (SAM) 210–12 self-assembly processes 51–2 biological systems 199–200, 218–19 controlling self-assembly of nanoparticles 212–15 molecular electronics 215–19 molecular logic gates 267–8 semiconductor devices 99 semiconductors 201–10 solid interfaces 210–12 supramolecular systems 199–223 towards molecular devices 199–221 self-sensitized photooxidation 391 semantic level of information semiconductor devices 63–117 absorption processes 84–9 adsorption at surfaces 97–8, 103–9 474 Index semiconductor devices (Continued) bulk properties and dispersion 63–6, 71–2, 74–6, 92 carbon nanostructures 149–56 charge migration 88–9 chemical composition 67–8 classification of nano-objects and nanomaterials 66–9 Coulomb blockade effects 71, 73–4 direct/indirect-gap semiconductors 85–7, 88 electrical and optical properties 70–96 electronic coupling 97–8, 103–9 future prospects 458 growth mechanisms and conditions 68–70 insulating particles 65–6, 74–7 low-dimensional metals 63–70 metal–insulator–metal devices 167, 168–78 metallic particles 65–6, 70–84 molecular clusters 65–6, 71 molecular information processing 42, 47, 51–2 molecular scale surface engineering 96–109 morphology of nanostructures 63–70 narrow band-gap semiconductors 94–6 performance characteristics 27–30 photoconductivity effects 88–90 photocurrent generation 90–1, 99 photoelectrochemical photocurrent switching 165–8 plasmon resonance 77–83 radiative and radiationless processes 89–90 semiconductor–molecule interactions 97–8, 100–9 wide band-gap semiconductors 84, 96–7 semiconductors biomimetic logic devices 426–8 molecular electronics 228 molecular logic gates 264 photoelectrochemical photocurrent switching 178–81 self-assembly processes 201–10 supramolecular systems 201–10 semimetals 120 sequential logic circuits 11–14, 262, 440–1 SERS see surface-enhanced Raman scattering Shannon–Landauer–von Neuman limit 20, 24 siderophores 364 sigmoidal filters 397–8 sigmoidal transfer characteristics 47–8 signal amplification 359–63, 413–14 signal transduction 38, 406–7 signal-to-noise ratios (SNR) 47, 359–63, 413–14 silver biomimetic logic devices 442–4 molecular computing systems 332, 342, 394 molecular logic gates 282–3 simple chain molecular junctions 226 single atom quantum dots 226 single crystal organic field-effect transistors (SC-OFET) 140, 144 single molecule see molecular single-walled carbon nanotubes (SWCNT) 120, 129–34, 137, 151–3 skin effects 30 smart dust systems 51 smart polymers 422–5 SNR see signal-to-noise ratios sodium 258, 264–6, 272, 282–3 soft errors 29 solar cells 96–7, 180, 187 solid interfaces 210–12 solid-state nanostructures 201 Soret bands 373 source–drain circuits 242–4 sp2 hybridization 119, 130 special theory of relativity 2, 23, 25–6, 121 spiropyrans biomimetic logic devices 416–17 carbon nanostructures 136 molecular computing systems 330, 337–41, 367, 370, 395 molecular logic gates 261–2, 265–6, 300 SRAM memory 151 steganography 386 stimulus/response curves 41 2-styrylquinoline 354–5 Su–Schrieffer–Heeger model 145 succinimides 270 superconducting devices 24 superexchange 227, 230 superimposed logic devices 324, 332–7 supramolecular systems biological systems 200–201, 218–19 controlling self-assembly of nanoparticles 212–15 molecular electronics 215–19 molecular logic gates 260–1, 266, 269, 287 Index self-assembly processes 199–223 semiconductors 201–10 solid interfaces 210–12 towards molecular devices 199–221 surface decoration 213–14 surface doping agents 107–9 surface effective electron affinity 100, 102 surface engineering 96–109 surface-enhanced Raman scattering (SERS) 310, 312 surface-modified semiconductors 181–92 surface plasmon resonance 77–83, 179, 417–18 surface potential 97–8, 100 SWAP gates 10, 16, 18 SWCNT see single-walled carbon nanotubes synaptic junctions synchronization of molecular events 39 syntactic level of information syntactic theory 2–3 T-latches 395–6 TAMRA fluorophore 430–1 TB see tight-binding TCNQ see tetracyanoquinodimethane technological limits of miniaturization 27–34 terbium complexes 274, 284 ternary-to-binary data converters 292 ternary logic 14–16, 289–98 TETA see triethylenetetramine tetracyanoquinodimethane (TCNQ) 169–70 tetraethynylene 289–90 tetrathiafulvalene (TTF) molecular computing systems 326–7, 369–70, 381–2 molecular electronics 238–9 molecular logic gates 259, 290–1 TFT see thin film transistors thermodynamics 2–4 thin film transistors (TFT) 140 thin-layer optoelectronic switches 177–8 thin-layer photodiodes 170–4 three-dimensional cell arrays 351–3 three-hybrid system 445–7 three-input AND gates 254, 263–6 three-input INH gates 281 three-input logic devices 324–6, 340 three-input NOR gates 300 three-state buffers 16 three-state switches 289–93, 377 475 TICT see transfer ICT tight-binding (TB) band structure 122–4 titanium dioxide 97, 179–92, 236–7 Toffoli gates 16–18 top-gate–bottom-contact configuration 150 top-gate–top-contact configuration 150 transfer ICT (TICT) 333–4 transversal plasmons 79–80 trianthryl cryptands 252–3 trichromophoric switches 347–8 triethylenetetramine (TETA) 342–3 trimethoprim 445–7 TRUE values 14–15 truth tables information theory 7–10, 15–16 molecular computing systems 335, 339, 341–3, 358, 396 molecular logic gates 312 TTF see tetrathiafulvalene tungsten gates 153 tunnel junctions 73–4 Turing machines 46 two-dimensional cell arrays 350–3 two-input AND gates 254 two-input NOR gates 300 unary ternary operators 14–15 unitary matrices 17–18, 20 UNKNOWN values 14–15 Urbach tails 84, 86–7, 180 van der Waals forces 212–13 Varshni empirical equation 87–8 Venn diagrams 5, 7–10 Vernier templating technique 209–10 viologens 174–5 Wannier–Mott excitons 149 Watson–Crick pairs 435–7 whole organism logic devices 445–50 wide band-gap semiconductors 84, 96–7, 189 work functions 72, 100 xenobiotic Watson–Crick pairs 435–7 XNOR gates information theory 8–9 molecular computing systems 324, 327, 334, 336, 374, 379, 382 molecular logic gates 268, 271, 288 476 Index XOR gates biomimetic logic devices 410–12, 415, 422, 432–3 carbon nanostructures 132–3, 155 information theory 8–10, 13, 15 molecular computing systems 328, 363–73, 375–82, 386 molecular electronics 242–3 molecular logic gates 267–72, 275, 303 photoelectrochemical photocurrent switching 173–6, 186, 191 YES function 331–3 YES gates biomimetic logic devices information theory 409, 421 photoelectrochemical photocurrent switching 186 YES–NOT logic 38, 45–6 zero band gap graphenes 120, 125 zigzag geometries 129–30 zinc molecular computing systems 324–6, 329–30, 335–6, 343–4, 364, 377, 393–4 molecular logic gates 263, 275, 279–80, 285–7 zinc selenide 96 zinc sulfide 94–5, 264 ZINDO calculations 183 Zitterbewegung 125 zone-folding approximation 130 zwitterions 239, 241 ... state Therefore the gate detects any high state at any of the inputs It computes the logic sum of input variables, that is it performs the disjunction operation The AND gate is another of the. .. potential source of further information does not mean that the author or the publisher endorses the information the organization or Website may provide or recommendations it may make Further, readers... automatically defines the unit of information Depending on the logarithm base the basic information units are bit (r ¼ 2), nit (r ¼ e) and dit (r ¼ 10) With r ¼ the information content of the event