Design of Electronic Devices Using Redox-Active Organic Molecules and Their Porous Coordination Networks (Springer Theses)

This book addresses the development of electronic devices using redox-active organic molecules and their porous coordination networks (PCNs), and highlights the importance of the molecular arrangement. Redox-active organic molecules hold considerable promise as flexible electronic elements, because their electronic state can easily be controlled using external energy. Although various kinds of redox-active organic molecules have been synthesized, attempts to apply them to electronic devices have been limited, owing to the lack of proper structural design. Moreover, ligand-based redox-active PCNs remain largely unexplored because of the limited availability of redox-active ligands. In addition to developing new redox-active organic molecules, in order to design electronic devices based on these molecules/PCNs, it is essential to understand the connections between their molecular arrangement, electrical properties, and redox activity. In this thesis, the redox-active organic molecule 2,5,8-tri(4-pyridyl)1,3-diazaphenalene (TPDAP), which features a large pi plane and multi-intermolecular interactivity, is used to develop a resistive switching memory device. In addition, its PCNs are synthesized to fabricate chemiresistive sensors, and the electrical properties are modulated using post-synthetic modification. Each mechanism is systematically investigated by means of structural determination and well-defined control experiments. Subsequently, the book proposes general guidelines for designing electronic devices using redox-active organic molecules. The book will appeal to a broad range of readers, from basic scientists to materials engineers, as well as general, non-expert readers. Supervisor’s Foreword 6 Abstract 8 Parts of this paper have been published in the following journal articles. 10 Acknowledgements 11 Contents 12 1 General Introduction 14 1.1 Redox-Active Organic Molecule 14 1.1.1 Redox (Oxidation–Reduction) Reaction 14 1.1.2 Redox-Active Organic Molecules 15 1.1.3 Phenalenyl Chemistry 17 1.2 Resistive Random Access Memory (ReRAM) 19 1.2.1 Conventional Memory Devices 19 1.2.2 Resistive RAM (ReRAM or RRAM) 20 1.2.3 Structure and General Characteristic of ReRAMs 21 1.2.4 Materials and Switching Mechanisms in ReRAMs 22 1.3 Redox-Active Porous Coordination Networks (PCNs) 23 1.3.1 Role of Redox-Activity in Metal–Ligand Cooperated System 23 1.3.2 Redox-Active Ligands 23 1.3.3 Porous Coordination Networks 24 1.3.4 Ligand-Based Redox-Active PCNs 25 1.3.5 Conductive PCNs 26 1.3.6 Chemiresistive Sensor Based on PCNs 27 1.4 Post-synthetic Modification (PSM) of PCNs 28 References 29 2 Resistive Switching Memory Devices Based on a Redox-Active Organic Molecule 33 Abstract 33 2.1 Introduction 33 2.2 Results and Discussion 35 2.2.1 Selective Formation of Redox-Active TPDAP Films 35 2.2.2 Current–Voltage (I–V) Characteristics of TPDAPs 38 2.2.3 Ex Situ Study of Resistive Switching Memory Devices 39 2.2.4 Selective Formation of Redox-Inert TPHAP Films 43 2.2.5 Current–Voltage (I–V) Characteristics of TPHAPs 45 2.2.6 Switching Mechanism 45 2.3 Conclusion 49 2.4 Experimental Section 49 2.4.1 General Experimental Information 49 2.4.2 Syntheses 49 2.4.3 Device Fabrication 50 2.4.4 X-ray Structure Analysis 51 References 53 3 Chemiresistive Sensor Based on Redox-Active Porous Coordination Networks 54 Abstract 54 3.1 Introduction 54 3.2 Results and Discussion 55 3.2.1 Selective Formation of Redox-Active PCNs 55 3.2.2 Film Fabrication of Redox-Active PCNs 56 3.2.3 Electrical Properties of Redox-Active PCNs 58 3.2.4 Chemiresistive Humidity Sensing Ability of Redox-Active PCN 59 3.2.5 Mechanism Investigation 62 3.3 Conclusion 65 3.4 Experimental Section 66 3.4.1 General Experimental Information 66 3.4.2 Syntheses 66 3.4.3 X-Ray Structure Analysis 67 3.4.4 Electrical Measurement 69 References 70 4 Tunable Electrical Properties of Redox-Active Porous Coordination Networks via Post-synthetic Modification 72 Abstract 72 4.1 Introduction 72 4.2 Results and Discussion 73 4.2.1 Pore Opening of a Redox-Active PCN by PSMs 73 4.2.2 Efficient Oxidation of Open Structure After PSMs 75 4.2.3 Tunable Electrical Properties via PSMs 76 4.3 Conclusion 79 4.4 Experimental Section 79 4.4.1 General Experimental Information 79 4.4.2 Syntheses 80 4.4.3 X-Ray Structure Analysis 80 4.4.4 Electrical Measurement 81 References 82 5 Summary and Outlook 83 5.1 Summary 83 5.2 Limitations and Future Work 85 References 86