SPIE PRESS This monograph contains comprehensive information on pyroelectric materials and their preparation, properties, and applications, such as uncooled wideband infrared detectors, particle generators, and ambient energy harvesters. The complete lifecycle of a pyroelectric material is presented here for readers—from the theory of operation, to structure, processing, and applications—providing a cohesive overview of essential concepts, including the theoretical background and current developments in the field of pyroelectric devices. The book describes the preparation, structure, properties, and figures of merit for practical pyroelectric materials such as triglycine sulfate, lead zirconate titanate, lithium tantalate, lithium niobate, barium strontium titanate, lead magnesium niobate-lead titanate, polyvinylidene fluoride, zinc oxide, and others, including the merits and demerits of their use in devices. P.O. Box 10 Bellingham, WA 98227-0010 ISBN: 9780819493316 SPIE Vol. No.: PM231 Bellingham, Washington USA Library of Congress Cataloging-in-Publication Data Batra, A. K. Pyroelectricmaterials:infrareddetectors,particleacceleratorsandenergyharvesters/ A.K. Batra, M.D. Aggarwal. pages cm Includes bibliographical references and index. ISBN 978-0-8194-9331-6 ISBN 978-0-8194-9332-3 ISBN 978-0-8194-9333-0 1. Pyroelectric detectors Materials. 2. Thermoelectric apparatus and appliances Design and construction. I. Aggarwal, M. D. II. Title. QC338.5.P95B38 2013 620.1'9 dc23 2013014472 Published by SPIE P.O. Box 10 Bellingham, Washington 98227-0010 USA Phone: +1.360.676.3290 Fax: +1.360.647.1445 Email: [email protected] www.spie.org Copyright © 2013 Society of Photo-Optical Instrumentation Engineers (SPIE) All rights reserved. No part of this publication may be reproduced or distributed in any form or by any means without written permission of the publisher. Thecontentofthisbookreflectstheworkandthoughtoftheauthor(s).Everyefforthas beenmadetopublishreliableandaccurateinformationherein,butthepublisherisnot responsible for the validity of the information or for any outcomes resulting from reliance thereon. Printed in the United States of America First printing Table of Contents Foreword ix Preface xi Acknowledgments xiii Glossary of Symbols and Abbreviations xv 1 Fundamentals of Pyroelectric Materials 1 1.1 Introduction 1 1.2 Classification of Dielectric Materials 1 1.3 Important Dielectric Parameters 5 1.3.1 Electric dipole moment 5 1.3.2 Polar and nonpolar dielectric materials 5 1.3.3 Electric polarization 5 1.3.4 Electric displacement or flux density D, dielectric constant :, and electric susceptibility (cid:1) 6 1.3.5 Spontaneous polarization 6 1.4 Electrostrictive Effect 7 1.5 Piezoelectric Phenomena 7 1.6 Pyroelectric Phenomenon 9 1.6.1 Pyroelectric current generation 11 1.7 Ferroelectric Phenomena 14 1.7.1 Ferroelectric domains 14 1.7.2 Ferroelectric hysteresis 14 1.7.3 Poling 15 1.7.4 Paraelectric effect 16 1.8 Conclusions 16 References 16 2 Pyroelectric IR Detectors 19 2.1 Introduction 19 2.2 IR Fundamentals 19 2.3 IR Detectors 21 2.4 Pyroelectric IR Detectors 22 2.4.1 IR-detector operation 22 v vi TableofContents 2.4.2 Pyroelectric-detector responsivity 24 2.4.3 Noise-equivalent power 26 2.4.4 Detectivity 27 2.4.5 Noise 28 2.5 Material Performance Parameters 29 2.5.1 Material figures of merit 30 2.6 Structural Design 30 2.6.1 Characteristics of absorbers 31 2.6.2 Single-element detector design 32 2.6.3 Thin-film-based detectors 34 2.6.4 Hybrid focal-plane arrays 35 2.6.5 Monolith-integrated focal-plane array 35 2.6.6 Advanced lithium-tantalate-detector array 36 2.6.7 Trap detector 37 2.6.8 Resonant detector 38 ™ 2.6.9 Srico TFLT detector 39 2.7 Pyroelectric-Detector Applications 41 2.8 Conclusions 42 References 42 3 Processing of Key Pyroelectric Materials 47 3.1 Introduction 47 3.2 Bulk Single Crystals 47 3.2.1 Growth of crystals from solution 47 3.2.2 Crystal growth from melt 48 3.3 Preparation of Ceramics 50 3.4 Thin-Film Deposition 51 3.4.1 Nonsolution deposition 51 3.4.1.1 Sputtering technique 51 3.4.1.2 Laser-ablation technique 52 3.4.1.3 Chemical-vapor-deposition technique 52 3.4.2 Solution deposition 54 3.4.2.1 Sol-gel technique 54 3.4.2.2 Metalorganic-deposition technique 55 3.5 Thick-Film Fabrication 59 3.5.1 Thick-film-transfer technology (screen printing) 59 3.6 Fabrication of Polymer–Ceramic Composite Precursors 60 References 62 4 Important Pyroelectrics: Properties and Performance Parameters 65 4.1 Introduction 65 4.2 Important Pyroelectrics 65 4.2.1 Triglycine sulfate crystals and their isomorphs 65 4.2.2 Modified lead titanate 69 TableofContents vii 4.2.3 Lead zirconate titanate 72 4.2.4 Lithium tantalate and lithium niobate 78 4.2.5 Barium strontium titanate materials system 81 4.2.6 Strontium barium niobate 84 4.2.7 Lead magnesium niobate-lead titanate (PMN-PT) 85 4.3 Organic Pyroelectrics 86 4.4 Pyroelectric–Polymer Composites 87 4.5 Other Pyroelectric Materials 91 4.5.1 Aluminum nitride (AlN) 91 4.5.2 Gallium nitride (GaN) 92 4.5.3 Zinc oxide (ZnO) 92 4.6 Lead-free Pyroelectric Ceramics 93 4.7 Conclusions 93 References 94 5 Innovative Techniques for Pyroelectric IR Detectors 105 5.1 Introduction 105 5.2 Multilayer Structures 105 5.3 Compositionally Graded Structures 107 5.4 Pyroelectric Heterostructures 109 5.5 Use of Nanoporosity 112 5.6 Novel Designs and Techniques 113 5.7 Conclusions 118 References 118 6 Pyroelectric Particle Generators 121 6.1 Introduction 121 6.2 Electrostatistics of a Pyroelectric Accelerator 122 6.2.1 One-crystal system 122 6.2.2 Two-crystal system 123 6.3 D–D Nuclear Fusion and Neutron Generators 125 6.4 Electron and Ion Emitters 129 6.5 X-ray Generators 129 6.6 Applications 131 6.7 Conclusions 131 References 131 7 Pyroelectric Energy Harvesting 135 7.1 Introduction 135 7.2 Energy Transfer 136 7.2.1 Ferroelectric effect 137 7.2.2 Paraelectric effect 138 7.2.3 Phase transitions 138 7.2.4 Pyroelectric performance 139 viii TableofContents 7.3 Thermodynamic Cycles for Pyroelectric Energy Conversion 139 7.3.1 Heat and work fundamentals 140 7.3.2 Pyroelectric energy harvesting efficiency 143 7.3.3 Carnot cycle for polarization–electric field (PE) cycles 144 7.3.4 Ericsson cycle for the PE cycle 145 7.3.5 Lenoir cycle for the PE cycle 146 7.3.6 Pyroelectric energy conversion based on the Clingman cycle 147 7.3.7 Pyroelectric energy conversion based on the Olsen cycle 148 7.4 Pyroelectric Energy Conversion and Harvesting: Recent Progress 150 7.4.1 Pyroelectric energy harvesting based on the direct pyroelectric effect 150 7.4.2 Pyroelectric energy harvesting based on thermodynamic cycles 163 7.5 Conclusions 168 References 169 Appendix Major Pyroelectric Manufacturing Companies 175 Index 177 Foreword Materials have played a revolutionary role in the development of the modern technological age, and their various applications have made our lives increasingly comfortable here on our home, the beautiful blue planet Earth. With the application of heat, pyroelectric materials produce electric current, qualifying them for use in uncooled infrared detectors. Infrared detectors are encounteredinavastnumberofapplicationsinbothwarandpeace.Manyof their uses are routine to us in everyday life—for example, the pyroelectric intruderswitch-cum-sensoristhekeytomostdomesticburglaralarmsystems. With the advent of new technologies, thermal sensing and imaging have become useful diagnostic tools for medical, industrial, and military applications. In medicine, infrared thermal imaging is applied to detect vascular disorders and arthritic rheumatisms as well as to monitor muscular performancesandmakepreclinicaldiagnosesofbreastcancer.Recently,these materialshavebeenusedinnuclearparticlegeneration,andtheirusefulnessin energy harvesting is currently under exploration. This monograph is the work of Drs. A. K. Batra and M. D. Aggarwal, two of the most prolific scholars and accomplished researchers in the field. Both have significantly contributed to the advancement of knowledge in pyroelectric materials. We are fortunate to have their expertise as part of the faculty of Alabama A&M University (AAMU), and weare grateful that they have been able to devote extra time and effort toward the preparation of this important contribution to pyroelectric literature. I have no doubt that this thought-provoking text will inspire further progress in the fascinating and challenging field of pyroelectrics. Andrew Hugine Jr., Ph.D. President Alabama A&M University Normal, Alabama August 2013 ix