학위논문 (석사)-- 서울대학교 대학원 : 재료공학부, 2013. 2. 조원호.A high-yielding dispersion of graphene at high concentration in solvent is critical for practical applications. Herein, we demonstrate the formation of stable dispersion of pristine graphene in ethanol by exfoliating graphite flakes into individual graphene layers using a non-ionic polymer surfactant under bath-type sonication. Oligothiophene-terminated poly(ethylene glycol) was synthesized and used as a non-ionic and amphiphilic surfactant for exfoliating graphite into graphene. High-quality graphene film was fabricated from the exfoliated graphene solution by the vacuum filtration method. TEM and SEM reveal that the size of exfoliated graphene flake is larger than 1 m. When the graphene film was treated with nitric acid and thionyl chloride after washing with solvent, the film showed high performance with a sheet resistance of 0.3 kΩ sq−1 and a transparency of 74% at 550 nm.Chapter 1 Introduction 1
Chapter 2 Experimental 6
2.1 Materials 6
2.2 Synthesis 6
2.2.1 Synthesis of (2, 5-dibromo-thiophene-3-yl)-acetic acid (2Br-1TN) 6
2.2.2 Synthesis of 2Br-1TN-PEG 7
2.2.3 Synthesis of quinquethiophene-PEG (5TN-PEG) 7
2.3 Preparation of graphene solution 9
2.4 Fabrication of graphene film 9
2.5 Measurements 10
Chapter 3 Results and Discussion 12
3.1 Exfoiation and dispersion of graphene 12
3.2 Fabrication of graphene film 16
3.3 Chemical treatment of graphene film 23
3.4 Comparison of electro-optical property of our graphene film with other works reported in the literature 30
Chapter 4 Conclusions 37
Bibliography 38
Korean Abstract 43Maste
