Electrochemistry of Metal Chalcogenides Monographs in Electrochemistry Surprisingly, a large number of important topics in electrochemistry is not covered by up-to-date monographs and series on the market, some topics are even not cov- ered at all. The series Monographs in Electrochemistry fills this gap by publishing indepth monographs written by experienced and distinguished electrochemists, cov- ering both theory and applications. The focus is set on existing as well as emerging methods for researchers, engineers, and practitioners active in the many and often interdisciplinary fields, where electrochemistry plays a key role. These fields will range – among others – from analytical and environmental sciences to sensors, mate- rials sciences and biochemical research. Information about published and forthcoming volumes is available at http://www.springer.com/series/7386 Series Editor: Fritz Scholz, University of Greifswald, Germany Mirtat Bouroushian Electrochemistry of Metal Chalcogenides 123 Dr. Mirtat Bouroushian National Technical University of Athens Dept. of Chemical Sciences School of Chemical Engineering Heroon Polytechniou Str. 9 Zographos Campus 157 73 Athens Greece [email protected] ISBN 978-3-642-03966-9 e-ISBN 978-3-642-03967-6 DOI 10.1007/978-3-642-03967-6 Springer Heidelberg Dordrecht London New York Library of Congress Control Number: 2009943933 © Springer-Verlag Berlin Heidelberg 2010 This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilm or in any other way, and storage in data banks. 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Ltd., Pondicherry Printed on acid-free paper Springer is part of Springer Science+Business Media (www.springer.com) Preface This monograph is devoted to the electrochemistry of metal chalcogenides, a group of chemical compounds which possess very interesting properties for applications in various areas, e.g., electronics and optics, ion-sensitive electrodes, solar energy harvesting, fuel cells, catalysis, and passivation. The role which electrochemistry plays in studies of metal chalcogenides is twofold: on one side it is a synthesis tool and on the other side it can be utilized for the characterization and analysis of these compounds. It is thus a basic requirement that the fundamentals of electrochemical thermodynamics and kinetics of these systems are thoroughly studied and docu- mented. The author Mirtat Bouroushian from the National Technical University of Athens must be given full credit for presenting the first book completely devoted to the electrochemistry of metal chalcogenides, a research topic to which he has made numerous own contributions. This monograph gives a well-balanced descrip- tion of the properties of chalcogens and their major chemical compounds together with the state-of-the-art electrochemical synthesis of various metal chalcogenide phases and their characterization, as well as an account of the wide range of appli- cations. Everybody who works with metal chalcogenides, and of course especially anybody dealing with the electrochemistry of these compounds, will find this mono- graph a very rich source of carefully and critically compiled information. I am sure that industrial electrochemists and researchers in institutes and universities as well as graduate students of material science, physics, electronics, and chemistry will highly appreciate to have this monograph at hands during their daily work. January 2010 Fritz Scholz EditoroftheseriesMonographs in Electrochemistry v Contents 1 Chalcogens and Metal Chalcogenides ................. 1 1.1 The Chalcogens . ....................... 1 1.1.1 History and Occurrence .................. 2 1.1.2 Production and Uses . .................. 4 1.1.3Allotropy–StatesofMatter................ 7 1.1.4 Chemical Properties and Compounds . ........ 10 1.1.4.1 Hydrides.................... 12 1.1.4.2 Oxides and Oxoacids . ............. 12 1.1.4.3 Thio- and Seleno-sulfates . ........ 14 1.1.4.4 Polychalcogenide Ions ............. 15 1.2 The Metal Chalcogenides . .................. 16 1.2.1Solids,Complexes,andClusters.............. 16 1.2.2CommonSolidStructures................. 19 1.2.3 Ternary Compounds and Alloys . ............. 22 1.2.4 Intercalation Phases . .................. 24 1.2.5 Chalcogenide Glasses . .................. 24 1.2.6 Materials Synthesis . .................. 25 1.2.7 An Account of the Periodic Table ............. 28 1.2.7.1 Group IA (1). Lithium, Sodium, Potassium,Rubidium,Cesium......... 28 1.2.7.2 Group IIA (2). Beryllium, Magnesium, Calcium,Strontium,Barium.......... 29 1.2.7.3 Group IIIA (3). Scandium, Yttrium, Lanthanoids, Actinoids ............. 29 1.2.7.4 Group IVA (4). Titanium, Zirconium, Hafnium 32 1.2.7.5 Group VA (5). Vanadium, Niobium, Tantalum . 33 1.2.7.6 Group VIA (6). Chromium, Molybdenum, Tungsten ............ 35 1.2.7.7 Group VIIA (7). Manganese, Technetium, Rhenium ............. 37 1.2.7.8 Group VIII (8–10). Iron, Cobalt, Nickel .... 38 vii viii Contents 1.2.7.9 Group VIII (8–10). Platinum Group Metals(Ru,Os,Rh,Ir,Pd,Pt)......... 40 1.2.7.10 Group IB (11). Copper, Silver, Gold . .... 41 1.2.7.11 Group IIB (12). Zinc, Cadmium, Mercury . 45 1.2.7.12 Group IIIB (13). Boron, Aluminum, Gallium, Indium, Thallium . ........ 48 1.2.7.13GroupIVB(14).Germanium,Tin,Lead.... 49 1.2.7.14GroupVB(15).Antimony,Bismuth...... 51 General References ........................... 52 References ................................ 52 2 Electrochemistry of the Chalcogens .................. 57 2.1 General References . ....................... 57 2.1.1 Tables of Aqueous Standard and Formal Potentials .... 59 2.1.2 Pourbaix Diagram for Sulfur–Water ............ 62 2.1.3 Pourbaix Diagram for Selenium–Water . ........ 64 2.1.4 Pourbaix Diagram for Tellurium–Water . ........ 65 2.2 General Discussion . ....................... 67 2.2.1Sulfur............................ 67 2.2.2Selenium.......................... 69 2.2.3Tellurium.......................... 71 References ................................ 73 3 Electrochemical Preparations I (Conventional Coatings and Structures) ............................. 77 3.1BasicPrinciplesandIllustrations................. 77 3.1.1 Cathodic Electrodeposition . ............. 78 3.1.2 Anodization and Other Techniques ............ 84 3.1.3 Pourbaix Diagrams . .................. 85 3.1.4NucleationandGrowth.................. 86 3.2 Binary Compounds and Related Ternaries ............ 88 3.2.1CadmiumSulfide(CdS).................. 88 3.2.2 Cadmium Selenide (CdSe) ................. 94 3.2.3CadmiumTelluride(CdTe)................ 98 3.2.4ZincSulfide(ZnS)..................... 103 3.2.5 Zinc Selenide (ZnSe) . .................. 104 3.2.6ZincTelluride(ZnTe)................... 105 3.2.7 Mercury Chalcogenides .................. 106 3.2.8 Pseudobinary II–VIx–VI1−x and II1−x–IIx–VI Phases . 106 3.2.9 Molybdenum and Tungsten Chalcogenides ........ 110 3.2.10 Copper Chalcogenides . .................. 112 3.2.11 Silver Chalcogenides . .................. 113 3.2.12 Indium Chalcogenides . .................. 114 3.2.13 Copper–Indium Dichalcogenides ............. 115 3.2.14 Manganese and Rhenium Chalcogenides . ........ 119 Contents ix 3.2.15 Iron Chalcogenides . .................. 120 3.2.16 Tin Chalcogenides . .................. 121 3.2.17 Lead Chalcogenides . .................. 124 3.2.18 Bismuth and Antimony Chalcogenides . ........ 128 3.2.19 Rare Earth Chalcogenides ................. 131 3.3 Addendum . ............................ 132 3.3.1 Chemical Bath Deposition ................. 132 3.3.2 Electrodeposited CdTe Solar Cells ............ 137 References ................................ 139 4 Electrochemical Preparations II (Non-conventional) ........ 153 4.1 General . ............................ 153 4.2 Epitaxial Films and Superstructures . ............. 154 4.2.1 Single-Step Epitaxy on Semiconductor Substrates .... 155 4.2.2 Electrochemical Atomic Layer Epitaxy . ........ 162 4.2.3 Superstructures–Multilayers . ............. 169 4.3 Atomic Layer Epitaxy and UPD Revisited ............ 172 4.4 Electrodeposition of Nanostructures: Size-Quantized Films on Metal Substrates . .................. 182 4.5DirectedElectrosynthesis..................... 187 4.5.1PorousTemplates..................... 189 4.5.2 Templated and Free-Standing Nanowires and otherForms........................ 191 4.5.3 Electrochemical Step Edge Decoration . ........ 196 References ................................ 198 5 Photoelectrochemistry and Applications ............... 207 5.1 General . ............................ 207 5.2 Photoelectrochemical Properties .................. 209 5.2.1 Redox and Surface Chemistry vs. Electrode Decomposition 210 5.2.2EnergeticConsiderations................. 213 5.2.3 Cadmium Chalcogenides ................. 216 5.2.3.1 Single-Crystal Photoelectrodes – PEC Fabrication and Properties