Poly(3-hexylthiothiophene) : precise synthesis, microstructure, and electro-optical properties

• Main Authors: Ning Chung, 鍾寧
• Other Authors: Chi-Yang Chao
• Format: Others
• Language: en_US
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/81375925414669630205

碩士 === 國立臺灣大學 === 材料科學與工程學研究所 === 105 === Poly(3-alkylthiothiophenes) (P3ATTs), polythiophenes having alkylthio side chains at 3-position of a thiophene repeating unit, are expected to offer the corresponding electronic devices better performance than the mostly studied poly(3-alkylthiophenes) (P3ATs), as the sulfur atom of the alkylthio side chain could donate the electron density to the polythiophene backbone and the S(thienyl)-S(alkylthio) interaction would enhance stacking to improve charge carrier mobilities. Despite the similarity in chemical structures of P3ATTs and P3ATs, the methodologies commonly adopted for precise syntheses of P3ATs could not successfully produce well-defined regioregular P3ATTs. In this thesis, a new monomer 2-bromo-5-iodo-3-hexylthiothiophene, different from all the monomers used in the reported works in Rieke, modified McCullough and GRIM methods, is synthesized and which could be polymerized via GRIM methods with mild reaction conditions to produce poly(3-hexylthiothiophene) (P3HTT) with high regioregularity, designated molecular weight and narrow molecular weight distribution. By systematically investigating the influences of reaction parameters in GRIM polymerization on MW and MWD, including temperature and reaction time; it is found that the polymerization temperature is critical to the livingness of polymerization and which predominates the MW control. The success in precise synthesis of P3HTTs enable us to study the effects of regioregularity and molecular weights on the optical absorptions and electronic band structures as well as on the supramolecular organization.