Chemical physics of nanostructured semiconductors / editors, Alexander I. Kokorin and Detlef W. Bahnemann.

Format:

Book

Contributor:

Kokorin, A. I. (Aleksandr Ilʹich)

Bahnemann, D. (Detlef)

Language:

English

Subjects (All):

Nanostructured materials.

Semiconductors.

Physical Description:

xv, 263 pages : illustrations ; 25 cm

Place of Publication:

Utrecht [The Netherlands] ; Boston [Mass.] : VSP, 2003.

Summary:

The research literature from the former Soviet Union on the chemical physics of nanostructured materials is not well known because of its publication in Russian books and journals. Kokorin (N. Semenov Institute of Chemical Physics, Russian Academy of Sciences) and Bahneman (physical chemistry, Carl-von-Ossietzky U., Germany) take this literature into account in their survey of the modern trends and data obtained in the research in the former Soviet Union and the West. The material particularly focuses on nanocrystalline semiconductors. Topics include charge separation by magnetic resonance, kinetic attributes of photocatalytic reactions, electron spin resonance, and other topics of electro- and photochemistry. Annotation (c)2003 Book News, Inc., Portland, OR (booknews.com)

Contents:

Chapter 1. Charge Separation in Titanium Oxide Nanocrystalline Semiconductors Revialed by Magnetic Resonance / T. Rajh, O. G. Poluektov, M. C. Thurnauer 1

1.2. Basic Mechanisms of Semiconductor-Assisted Photocatalysis 2

1.2.1. Energy Band Structure of TiO2 Nanoparticles 2

1.2.2. Photogeneration of Charge Pairs and Intrinsic Properties of Semiconductors 4

1.2.3. Space Charge Layer and Band Banding 5

1.3. Charge Separation and Carrier Trapping in TiO[subscript 2] Nanoparticles 6

1.3.1. Nature of Trapping Sites 6

1.3.2. Hole Trapping Sites 7

1.3.4. Charge Separation in the Surface-Modified TiO[subscript 2] Colloids 14

1.4. Kinetic and Mechanism of the Charge Separation in TiO[subscript 2] Colloid Nanoparticles as Studied by Time-Resolved EPR Technique 23

Chapter 2. Kinetic Peculiarities of Photocatalytic Reactions on CdS Nanocolloids / D. V. Bavykin, E. N. Savinov, I. N. Martyanov, V. N. Parmon 35

2.2. Synthesis of CdS Colloids 35

2.2.1. Thermodynamic Calculation of Equilibrium Size of CdS Colloidal Particles in the Presence of Cadmium Components 36

2.2.2. Method of CdS Preparation 39

2.3. Reaction of Interfacial Electron Transfer as the First Stage of Redox Photocatalytic Processes 40

2.3.1. Photobleaching Relaxation of Colloids 40

2.3.2. Physical Causes Resulting in the Observable Kinetic Peculiarities of Photobleaching Relaxation 45

2.3.3. Effect of CdS Adsorption Properties on the Kinetics of Its Photo-bleaching Relaxation in the Presence of Various Electron Acceptors 48

2.4. Luminescence Quenching of CdS Colloids 51

2.4.1. Regularities of Luminescence Quenching of Colloidal CdS Particles 52

2.4.2. Effect of Surface Properties of Ultradispersed CdS on Regularities of Luminescence Quenching 59

2.4.2.a. Luminescence Quenching of Colloidal CdS by Quenchers of Various Nature 59

2.4.2.b. Effect of the Surface Charge of Colloidal CdS on the Efficiency of its Luminescence Quenching by Various Quenchers 61

2.4.3. Effect of Excitation Wavelength on the Luminescence Spectrum of CdS/Cu[subscript x]S 62

2.5. Kinetics of Photocatalytic Reactions at Stationary Illumination 65

2.5.1. Photoreduction of Methyl Orange on CdS Colloids in Deep Conversion 65

2.5.1.a. Kinetic Peculiarities of Photocatalytic Processes on Ultradispersed CdS Colloids at Stationary Illumination 66

2.5.1.b. Semiquantitative Description of the Kinetics of Photocatalytic Processes on CdS Colloids in Terms of Adsorption-Desorption Processes in the System 69

2.5.1.c. Analysis of Kinetic Regularities of the System under Study 72

2.5.2. Photoreduction of Methylviologen and Phosphotungstic Acid on CdS Colloids; Effect of Surface Charge 77

2.5.3. Effect of Excitation Light Wavelength on the Rate of Photocatalytic Reaction 80

Chapter 3. Photooxidation of Water at Hematite Electrodes / T. Lindgren, L. Vayssieres, H. Wang, S.-E. Lindquist 83

3.2. General Background of Photooxidation of Water 85

3.3. Structural and Physical Properties of Hematite 89

3.3.1. Crystal Structure 89

3.3.2. Electronic Structure 90

3.3.3. Electrical Properties 92

3.3.4. Flat-band Potential 92

3.4. Photoresponse of Hematite Materials 95

3.4.1. Colloidal Solutions of Hematite 96

3.4.2. Hematite Single Crystal Materials 97

3.4.2.a. Hematite Single Crystal 97

3.4.2.b. Doped Hematite Single Crystal 97

3.4.2.c. Mixed Hematite Single Crystal 98

3.4.3. Polycrystalline Hematite Materials 98

3.4.3.a. Polycrystalline Hematite 98

3.4.3.b. Polycrystalline Hematite Thin Film 98

3.4.3.c. Polycrystalline Doped Hematite 100

3.4.3.d. Mixed Polycrystalline Oxides of Hematite 102

3.4.4. Nanostructured Thin Films of Hematite 102

3.4.4.a. Nanostructured Films of Spherical Particles of Hematite 102

3.4.4.b. Hematite Nanorods 104

Chapter 4. Photoelectrochemistry of Nanocrystalline Aggregates of Cyanine Dyes on the Semiconductor Electrodes / D. V. Sviridov 111

4.2. Spectroscopic Properties of Aggregated Cyanine dyes 111

4.3. Effect of Aggregate Formation upon Electronic Energy Levels of Cyanine Dyes (CDs) 114

4.4. Aggregates of Cyanine Dyes as the Sensitizing Agents in the Photoelectrochemical Systems 116

4.5. Photoelectrochemical Spectral Sensitization by Partially Aggregated CDs 120

4.6. Spectral Sensitization of Semiconductor by Mixture of J-aggregated CDs 125

4.7. Photoelectrochemical Behaviour of Thin Films of Aggregated CDs 127

Chapter 5. Physico-Chemical Properties of Novel Nanocrystalline Ruthenium Based Chalcogenide Materials / N. Alonso-Vante 135

5.2. Clusters or Particles 136

5.2.1. Size Comparison 136

5.2.2. Metal and Semiconductor Nanoparticles 138

5.3. A Non-aqueous Chemical Route of Synthesis 139

5.3.1. Synthesis Ideals 139

5.3.2. The Chemical Route 140

5.3.3. Morphology and Stoichiometry 140

5.4. Electrocatalysis and Photoelectrocatalysis 142

5.4.1. Thin to Ultra Thin Layers of Chalcogenide Materials 142

5.4.2. Electrocatalysis via Thin and Ultra Thin Layers of Chalcogenide Materials 144

5.4.3. (Photo)Electrocatalysis on Nanostructured TiO[subscript 2] Surface Modified via Chalcogenide Materials 145

5.4.4. Implications of Molecular Oxygen for Photooxidation Process 147

Chapter 6. Metal Nanoparticles on Semiconductor Surfaces: Electrochemistry and Photocatalysis / A. I. Kulak 153

6.2. Dependence of Nanoparticles Morphology and Behavior in Electron Transfer Processes on the Mean of Metal Nanophase Deposition onto Semiconductor Surface (ScS) 155

6.2.1. Contact Deposition of Metal Nanoparticles onto ScS 155

6.2.2. Galvanic Deposition of Metal Nanoparticles onto ScS 158

6.2.3. Photocatalytic Formation of Metal Nanophase on Semiconductor Surfaces 161

6.3. Formation of Electronic Surface States in Semiconductor Band Gap as a Result of Deposition of Metal Particles on Semiconductor Surface 166

6.4. Electrocatalytic Activity of Semiconductor Electrodes Modified by Surface-Deposited Metal Nanophase 171

6.5. Impedometric Investigation of Titania Electrodes Surface-Modified with Metal Particles 174

6.6. Interaction of Metal Nanoparticles with the Associates of Donor Defects in Wide-Band-Gap n-type Semiconductors 177

Chapter 7. Photocatalysis: Electron Transfer Serving the Environment / D. W. Bahnemann, R. Dillert, P. K. J. Robertson 183

7.2. Primary Processes upon Band Gap Irradiation of Semiconductor Particles 184

7.3. Chemical Nature of Trapped Charge Carriers 187

7.4. Fate of Trapped Charge Carriers 189

7.4.1. Recombination Kinetics 189

7.4.2. Charge Transfer Kinetics 191

7.4.2.a. Interfacial Electron Transfer 191

7.4.2.b. Direct Interfacial Hole Transfer 192

7.4.2.c. Hole Transfer through the Intermediate Formation of Hydroxyl Radicals 195

Chapter 8. Electron Spin Resonance of Nanostructured Oxide Semiconductors / A. I. Kokorin 203

8.2. EPR Signals of Oxide Semiconductors 205

8.3. EPR of Small Molecules Adsorbed on the Semiconductor Surface 209

8.3.1. Oxygen Radicals 209

8.3.2. N[subscript x]O[subscript y] Radicals 211

8.4. Structural Aspects in the Study of Nanocrystalline Materials 215

8.4.1. The Measurement of Local Concentration of Paramagnetic Centers 219

8.4.2. Regularities and Peculiarities of Spatial Distribution of PCs 221

8.5. Vanadium Ions "Behaviour" in/on Oxide Semiconductors 224

8.5.1. Titanium Dioxide 225

8.5.1.a. Substitutional and Interstitial Centers 227

8.5.1.b. Surface Doping 230

8.5.2. Other Oxides 236

8.6. Other Paramagnetic Dopants 238

8.7. Identification of Adsorbed Cu[superscript n+] Ions at the TiO[subscript 2] Surface and Electro-Chemical Behaviour of Copper-Modified Electrodes 242.

Notes:

Includes bibliographical references.

ISBN:

9067643823

OCLC:

52746773