Core/Shell Quantum Dots: Synthesis, Properties and Devices

Description

This book outlines various synthetic approaches, tuneable physical properties, and device applications of core/shell quantum dots (QDs). Core/shell QDs have exhibited enhanced quantum yield (QY), suppressed photobleaching/blinking, and significantly improved photochemical/physical stability as compared to conventional bare QDs. The core-shell structure also promotes the easy tuning of QDs’ band structure, leading to their employment as attractive building blocks in various optoelectronic devices. The main objective of this book is to create a platform for knowledge sharing and dissemination of the latest advances in novel areas of core/shell QDs and relevant devices, and to provide a comprehensive introduction and directions for further research in this growing area of nanomaterials research.     Preface Contents Synthesis, Properties, and Applications of II –VI Semiconductor Core/Shell Quantum Dots 1 Introduction 1.1 Classification of Core/Shell Quantum Dots 2 Synthesis of Core and Core/Shell Semiconductor QDs 2.1 Synthesis of Core QDs 2.1.1 Injection Method 2.1.2 Non-injection Method 2.2 Synthesis of Semiconductor Core/Shell QDs 2.2.1 Synthesis and Characterization of Type I Core/Shell QDs 2.2.2 Synthesis and Characterization of Type II Core/Shell QDs 2.2.3 Synthesis and Characterization of Reverse Type I Core/Shell QDs 3 Applications of Semiconductor Core/Shell QDs 3.1 Solar Cells 3.2 Light-Emitting Diodes (LEDs) 3.3 Applications in Biology 3.3.1 Biosensing 3.3.2 Gene and Drug Delivery 3.3.3 Therapy 4 Summary and Prospects References Design, Synthesis, and Properties of I-III-VI2 Chalcogenide-Based Core-Multishell Nanocrystals 1 Introduction 1.1 Classes of Core/Shell Nanocrystals 2 Design and Formation of Core-Multishell and Alloyed Shell Nanocrystals 2.1 Synthesis of Core/Shell Nanocrystals 2.2 Growth of Multishell Over Core Nanocrystals 2.3 Optical Properties of Mn2+ Ion-Doped Core and Core/Shell CuInS2 Nanocrystals 2.4 Photoluminescence Properties of Mn2+ Ion-Doped Core and Core/Shell CuInS2 Nanocrystals 2.5 XPS Analysis of Mn2+ Ion-Doped Core and Core/Shell CuInS2 Nanocrystals 2.6 Crystal Structure Analysis of Mn2+ Ion-Doped Core and Core/Shell CuInS2 Nanocrystals 2.7 Morphological Properties of Mn2+ Ion-Doped Core and Core/Shell CuInS2 Nanocrystals 2.8 Absorption Properties of Core-Multishell CuInS2/MnS/ZnS Nanocrystals 2.9 Photoluminescence Analysis of Core-Multishell CuInS2/MnS/ZnS Nanocrystals 2.9.1 Influence of Shell Concentration on PL Properties of CuInS2/MnS/ZnS Core-Multishell Nanocrystals 2.10 X-Ray Photoelectron Spectroscopy (XPS) Analysis of Core-Multishell CuInS2/MnS/ZnS Nanocrystals 2.11 Crystal Structure Analysis and the Influence of Shell Concentration on Crystal Structure of Core-Multishell CuInS2/MnS/ZnS Nanocrystals 2.12 Morphological Analysis of CuInS2/MnS/ZnS Core-Multishell Nanocrystals 2.13 UV-Vis Absorption Spectra of Cd2+-Doped Core and Core/Shell AgInS2 Nanocrystals 2.14 Photoluminescence Properties of Cd2+-Doped Core and Core/Shell AgInS2 Nanocrystals 2.15 Crystal Structure Analysis of Cd2+-Doped Core and Core/Shell AgInS2 Nanocrystals 2.16 Surface Morphology Analysis of Cd2+-Doped Core and Core/Shell AgInS2 Nanocrystals 2.17 Elemental Compositions of Cd2+-Doped Core and Core/Shell AgInS2 Nanocrystals 2.18 UV-Vis Studies of Core-Multishell and Alloyed AgInS2/CdS/ZnS Shell Nanocrystals 2.19 Photoluminescence Studies of Core-Multishell and Alloyed AgInS2/CdS/ZnS Shell Nanocrystals 2.20 XPS Spectra of Core-Multishell and Alloyed AgInS2/CdS/ZnS Shell Nanocrystals 2.21 Crystal Structure Analysis of Core-Multishell and Alloyed AgInS2/CdS/ZnS Shell Nanocrystals 2.22 Morphological Studies of Core-Multishell and Alloyed AgInS2/CdS/ZnS Shell Nanocrystals 3 Conclusions References Unique Luminescent Properties of Composition-/Size-Selected Aqueous Ag-In-S and Core/Shell Ag-In-S/ZnS Quantum Dots 1 Introduction 2 Aqueous Synthesis and Optical Properties of AIS and AIS/ZnS QDs 2.1 Optimization of the Synthesis of Aqueous AIS and AIS/ZnS QD Ensemble Colloids 2.2 Size Selection of AIS and AIS/ZnS QDs 2.3 Static PL of the Size-Selected AIS and AIS/ZnS QDs 2.4 Time-Resolved Photoluminescence of the Size-Selected GSH-Stabilized AIS and Core/Shell AIS/ZnS QDs 2.5 Single-Particle PL Measurements 3 Temperature-Dependent Luminescence of AIS and AIS/ZnS QDs 3.1 Temperature Range of 10–80 C 3.1.1 Variations of PL Intensity 3.1.2 Variations of the PL Band Maximum Position 3.1.3 Variations of the PL Decay Rate 3.2 Temperature Range of 10–300 K 4 Summary References Electronic and Optical Characteristics of Core/Shell Quantum Dots 1 Introduction 2 Theory 2.1 One Particle States in Spherical Core/Shell QD 2.2 Impurity States in Spherical Core/Shell QD 2.3 Two-Electron Sates in Thin Spherical Core/Shell QD: Two Electrons on a Sphere 2.4 Interband Optical Absorption in Spherical Core/Shell QD 2.5 Quadrupole Moment Created by Impurity Electron in the Core/Shell QD 2.6 Orbital and Spin Magnetic Moment Current in the Cylindrical Core/Shell QD 2.6.1 Cylindrical Nanolayer 3 Conclusion References Exciton –Phonon Interactions and Temperature Behavior of Optical Spectra in Core/Shell InP/ZnS Quantum Dots 1 Introduction 2 Nanocrystal Absorption and Derivative Spectrophotometry 3 Temperature Dependence of the Energy Gap 4 The Influence of Exciton–Phonon Interaction on the Energy of Optical Transitions 5 The Half-Width of the First Exciton Absorption Band 6 Temperature Evolution of the First Exciton Absorption Band of QD Ensemble 6.1 Static and Dynamic Disorder in Ensemble 6.2 The Behavior of the Exciton Line of an Individual Nanocrystal 6.3 QD Size Distribution 6.4 Contributions of Homogeneous and Inhomogeneous Broadening 6.5 Simulation of Experimental InP/ZnS Ensembles 6.6 Disorder Effects in Temperature Band Broadening 7 Conclusion References Thick-Shell Core/Shell Quantum Dots 1 Thick-Shell Core/Shell Quantum Dots 1.1 History of Thick-Shell Core/Shell Quantum Dots 1.2 Basic Characteristics of Thick-Shell Core/Shell Quantum Dots 2 Synthesis of Thick-Shell Core/Shell Quantum Dots 2.1 Successive Ionic Layer Adsorption and Reaction Method 2.2 Syringe Pump Injection 2.3 “Flash” Hot Injection 3 Optical Properties of Thick-Shell Core/Shell Quantum Dots 3.1 Fundamental Optical Properties 3.2 Exciton Dynamics Process 3.3 Quantum Confined Stark Effect 3.4 Optical Gain Performance 3.5 Stimulated Radiation from Thick-Shell Core/Shell Quantum Dots 4 Conclusion References Core/Shell Quantum-Dot-Sensitized Solar Cells 1 Introduction 2 Brief History of QDSCs 3 QDSC Architecture 3.1 Anode 3.2 Light Harvester 3.3 Electrolyte 3.4 Counter Electrode 4 Working Principle 4.1 Light Absorption 4.2 Carrier Separation 4.3 Carrier Transport 4.4 Recombination 5 Photovoltaic Characterizations 6 Core/Shell QDs 6.1 Classification of Core/Shell QD Systems 6.2 Synthesis of Core/Shell QDs 7 Photovoltaic Performance of Core/Shell QDSCs 7.1 Type-I Core/Shell QDs 7.2 Reverse Type-I Core/Shell QDs 7.3 Type-II Core/Shell QDSCs 7.4 Quasi-Type-II Core/Thick-Shell QDs (“Giant” Core/Shell QDs) 7.5 Core and Shell Interface Optimization 8 Conclusions References Core/Shell Quantum-Dot-Based Solar-DrivenPhotoelectrochemical Cells 1 Introduction 1.1 Conversion of Solar Energy into Hydrogen 1.2 Working Principle of Solar-Driven PEC Cell for Hydrogen Generation 2 Synthesis and Optical Properties of Core/Shell QDs 2.1 Synthesis of Core/Shell QDs 2.2 Optical Properties of Core/Shell QDs 2.2.1 Type I Core/Shell QDs 2.2.2 Type II Core/Shell QDs 2.2.3 Quasi-Type II Core/Shell QDs 2.3 Charge Dynamics of Core/Shell QDs 2.3.1 Type I Core/Shell QDs 2.3.2 Type II and Quasi-Type II Core/Shell QDs 2.3.3 Charge Dynamics from QDs to Semiconductor Films 3 Solar-Driven PEC Cells Based on Core/Shell QDs 3.1 Core/Thin-Shell QDs 3.2 “Giant” Core/Shell QDs 3.3 Core/Alloyed-Shell/Shell QDs 4 Heavy Metal-Free Core/Shell QD-Based PEC Cells 5 Conclusions and Perspectives References Core/Shell Quantum-Dot-Based Luminescent Solar Concentrators 1 Introduction of Luminescent Solar Concentration 2 Band Alignment and Optical Properties of Core/Shell Quantum Dots 2.1 Exciton Dynamic in Core/Shell Quantum Dots 2.2 Stokes Shift in Core/Shell Quantum Dots 2.3 Quantum Yield in Core/Shell Quantum Dots 2.4 Stability of Core/Shell Quantum Dots 3 Luminescent Solar Concentrator Based on Core/Shell Quantum Dots 3.1 Near-Infrared PbS/CdS Core/Shell QD-Based LSCs 3.2 Visible CdSe/CdS Core/Shell QD-Based LSCs 3.3 Eco-Friendly InP/ZnO Core/Shell QD-Based LSCs 3.4 Cu-Based Ternary or Quaternary Eco-Friendly Core/Shell QD-Based LSCs 4 Conclusions and Perspectives References Index