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광전기 응용을 위한 π-공액계 물질의 초분자 상호 작용 조절에 관한 연구

Control of Supramolecular Interactions of π-Conjugation Materials for Optoelectronic Applications

  • 이승철 (Seung-Chul Lee, 일반대학원)

초록/요약

During past decade, π-conjugation molecules have received attention as one of promising candidate for organic-based devices However, the performance of organic-based devices based on π-conjugation molecules is significantly influenced characteristics of the surrounding environmental, because π-conjugation molecules easily interact with nearby molecules via supramolecular interaction, which affect performance of π-conjugation molecules. As a result, the detailed understanding of the supramolecular interactions between the individual π-conjugated molecules (or π-conjugated molecules and additive (or solvent)) has become one of the most challenging scientific research areas. The objectives of this dissertation are to understand supramolecular interaction of different type of π-conjugation molecules in various environmental. For the study, different type of π-conjugation molecules such as conducting polymer (polyaniline), neutral type chromophore and ionic type chromophore were synthesized and characterized by 1H-nuclear magnetic resonance (NMR) spectroscopy, fourier transform infrared spectroscopy, UV-Vis-NIR spectroscopy, differential scanning calorimeter (DSC) and thermogravimetric analysis (TGA). In chapter 1, It is reported about photoactive conducting polymers, which consist of conducting polymer (PANI) mixed with photo active additive(LCM) having mimic group. The mimic group on LCM can improve supramolecular interaction between conducting polymer and photo active additive. Thus, LCM show high miscibility with PANI. The PNA (polyaniline mixed with LCM agent) film not only maintain the high electrical conductivity of over 102 S/cm, but also exhibit fast reversible light-driven conductivity modulation of up to 0.8 S/cm without requiring additional erasing light at 514nm. Moreover, the PNA film exhibits good repeatability of modulation cycles and high photochemical stability at relatively high power intensity of pump light (183 mW/cm2). In chapter 2, it is reported about pyrrole molecular rotors act as viscosity sensor, which is designed not to interact with surrounding solvent molecule. Pyrrole rotors exhibit one order of magnitude higher fluorescence contrast compared to that of the conventional phenolic molecular rotor due to the viscosity-sensitive rotation of the asymmetric pyrrole group and successfully demonstrate mapping of intracellular viscosity by fluorescence lifetime imaging microscopy. In chapter 3, it is reported about a series of fluorescent molecular rotors with two rotational groups.. They also do not interact with surrounding molecules. While the control molecular rotor, PH, includes a single rotator, PO molecular rotors consist of two rotators, a phenyl group and an alkoxy group, which exhibits simultaneous strong electron-donating and easy rotational abilities.The introduction of two rotators, including alkoxy groups exhibiting both strong electron-donating and highly viscosity-sensitive rotational abilities, is a potential design tool for developing highly efficient fluorescent molecular rotors with high fluorescence contrast. In chapter 4, it is reported ionic organic PMB-T crystal with acentric crystal structure by supramolecular self-assembly. The benzothiazolium PMB-T crystal with extremely large macroscopic optical nonlinearity, which is roughly 2times higher than that of pyridinium-based DAST crystal. New core structure PMB cation,which consist of an strong electron-donating supramolecular building block PM (piperidin-4-ylmethanol) and a strong N-methylbenzothiazolium electron-acceptor., is used with 4-methylbenzenesulfonate (T) counter anion. The new benzothiazolium based PMB-T crystal exhibit an acentric crystal structure with optimal molecular packing for maximizing the second-order optical nonlinearity.

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목차

PART 1. General Introduction 1
1. π-conjugation molecules 2
1.1 π-conjugated polymers 5
1.2 Fluorescent dyes for molecular rotors 8
1.3 Organic nonlinear optical (NLO) materials 11
2. Supramolecular interaction of π-conjugation molecules 15
PART 2. Tailor-made Supramolecular Interactions of π-Conjugation Materials 18
Chapter 1. Photoactive Conducting Polymers with Light-driven Conductivity Modulation: Dual Functionality for Simple Circuits 19
1.Introduction 20
2. Experiments 22
2.1 Synthesis 22
2.1.1 Materials and characterizations 22
2.1.2 Synthesis of LCM agent 22
2.2 Preparation of photoactive polyaniline films 24
2.3 LCM experiments 24
3. Results and Discussion 25
4. Conclusion 47

Chapter 2. Pyrrolic Molecular Rotors Acting as Viscosity Sensors with High Fluorescence Contrast 48
1.Introduction 49
2. Experiments 51
2.1 Synthesis 51
2.1.1 Materials and characterizations 51
2.1.2 Synthesis of pyrrolic rotors 51
3. Results and Discussion 55
4. Conclusion 71
Chapter 3. Molecular Viscosity Sensors with Two Rotators for Optimizing Fluorescent Intensity-Contrast Trade-off 72
1.Introduction 73
2. Experiments 75
2.1 Synthesis 75
2.1.1 Materials and characterizations 75
2.1.2 Synthesis of PO rotors 75
2.2 Time-correlated single photon counting (TCSPC) measurements 77
2.3 Computational methods 78
2.4 Fluorescence imaging of live cells 78
2.5 Crystal structures 79
3. Results and Discussion 81
4. Conclusion 102
Chapter 4. Extremely Large Nonlinear Optical Benzothiazolium Crystals with Linear Hydrogen-bonding Mediated Cation and Anion Assembly 103
1.Introduction 104
2. Experiments 106
2.1 Synthesis 106
2.1.1 Materials and characterizations 106
2.1.2 Synthesis of PMB compounds 106
2.2 Growth of single PMB-T crystals 108
3. Results and Discussion 110
4. Conclusion 120
PART 3. Conclusions 121
1.Conclusions 122
PART 4. References 125
Part 1 126
Chapter 1 of Part 2 131
Chapter 2 of Part 2 136
Chapter 3 of Part 2 139
Chapter 4 of Part 2 143

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