1st Edition
Oxide Semiconductors for Solar Energy Conversion Titanium Dioxide
Oxide semiconductors, including titanium dioxide (TiO2), are increasingly being considered as replacements for silicon in the development of the next generation of solar cells. Oxide Semiconductors for Solar Energy Conversion: Titanium Dioxide presents the basic properties of binary metal oxide semiconductors and the performance-related properties of TiO2 as they relate to solar energy.
The book provides a general background on oxide semiconductors based on binary oxides and their solid solutions, including electronic and ionic conductors. It covers several aspects of solid-state electrochemistry of oxides, such as defect chemistry, and defect-related properties, such as electrical properties, diffusion, segregation, and reactivity. The author also takes a pioneering approach in considering bulk versus surface semiconducting properties, showing how they are different due to the effect of segregation.
One of the first on semiconducting, photocatalytic, and photoelectrochemical properties of TiO2 and its solid solutions with donor- and acceptor-type ions, the book discusses defect chemistry of TiO2 in terms of defect equilibria and defect-related properties, including electrical properties, self and chemical diffusion, surface properties, segregation, and reactivity and photoreactivity with oxygen, water, and microbial agents. The text also illustrates the use of TiO2 as an emerging material for solar energy conversion systems, including the generation of hydrogen fuel by photoelectrochemical water splitting, the photocatalytic purification of water, and the generation of photovoltaic electricity. In addition, it presents defect disorder diagrams for the formation of TiO2-based semiconductors with controlled properties.
Encompassing the areas of solid-state science, surface chemistry, and photocatalysis, this book reflects the increasing awareness of the importance of structural imperfections, such as point defects, in understanding the properties of metal oxides, specifically TiO2-based semiconductors.
Solid-State Electrochemistry of Binary Metal Oxides
Structural Defects
Nonstoichiometry
Point Defects in Binary Metal Oxides
Band Model
Electrical Properties
Effect of Interfaces
Diffusion
Oxygen Ion Conductors
Concluding Remarks
Light-Induced Effects
Solar Radiation
Solar Energy Spectrum
Light Source
Light-Induced Effects in Semiconductors
Data Reproducibility
Energy Conversion Efficiency
Light Measurements
Concluding Remarks
Basic Properties of TiO2
Titanium Oxides
Titanium TiO2
Concluding Remarks
Defect Chemistry
Undoped TiO2
Doping with Aliovalent Ions
Reactivity of TiO2 with Hydrogen
The Real Chemical Formula of TiO2
Concluding Remarks
Electrical Properties
Introduction
Electrical Conductivity
Thermoelectric Power
Jonker Analysis
Work Function
Surface Photovoltage Spectroscopy
Hall Effect
Coulometric Titration
Concluding Remarks
Diffusion
Mass Transport Kinetics
Self-Diffusion
Chemical Diffusion
Concluding Remarks
Effect of Interfaces
Effect of Surface Properties on Reactivity
Segregation
Reactivity
Concluding Remarks
Applications
Performance-Related Properties
Solar Hydrogen
Hydrogen Generation by Photoelectrochemical Water Splitting
Solar Water Purification
Alternative Applications
Summary and Concluding Remarks
Appendix
Index
References and Problems appear at the end of each chapter.
Biography
Janusz Nowotny is a professor of solar energy technologies at the University of Western Sydney. He has been a recipient of the Sir William Grove Award of the International Association for Hydrogen Energy and the Pfeil Award of the Institute of Materials, Minerals and Mining in London. Dr. Nowotny was the director of a NATO Advanced Research Workshop on Nonstoichiometric Compounds — Surfaces, Grain Boundaries and Structural Defects. He was also the founder and co-organizer of two series of International Workshops: Nonstoichiometric Compounds and Ceramic Interfaces.
… first comprehensive view on all the diverse properties of this material. … It is of invaluable importance for the entire materials science community. The book may be used as textbook for academic classes and researchers interested in the application of titania and titania-based materials. … The readers may find a wide range of materials data on mass and charge transport kinetics, segregation as well as a wide range of alternative defect-related properties of TiO2. Since assignable problems are given for each chapter, the book is also very useful for graduate classes in Materials Science and Engineering. It is a must for a wide community of researchers and developers.
—Werner Weppner, International Journal of Hydrogen Energy 37, 2012The present book provides a comprehensive survey of defect chemistry and defect-related properties of oxides, including electronic structure, charge transport, diffusion, and segregation. … [This] book is probably the only survey on semiconducting and photocatalytic properties of TiO2 at present, particularly with respect to inclusion of the importance of defect chemistry. The research of the author in this area has attracted the prestigious award of the International Association for Hydrogen Energy. This book should be welcomed by the large research community interested in oxide semiconductors in general and TiO2 in particular, as well as the growing community interested in photocatalysis.
—Professor Eric D. Wachsman, University of MarylandThis book of Prof. Nowotny is addressing the increasingly urgent need for a treatise on oxide semiconductors in general and TiO2-based semiconductors in particular. … This book, which is the first extensive survey on the science of TiO2, will be of great help to the research community involved in the studies of the properties of TiO2.
—Professor Sebastian Fiechter, Helmholtz-Centre Berlin for Materials and Energy
