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URN etd-0801107-123921 Statistics This thesis had been viewed 3388 times. Download 2182 times. Author Chuan-Shun Syu Author's Email Address firstname.lastname@example.org Department Chemical Engineering Year 2006 Semester 2 Degree Master Type of Document Master's Thesis Language Chinese&English Page Count 98 Title STUDIES ON THE SYNTHESIS AND APPLICATION OF REGIOREGULAR POLYTHIOPHENES AND COPOLYMERS ON THE CHARACTERISTICS OF ORGANIC FIELD-EFFECT TRANSISTOR Keyword STUDIES ON THE SYNTHESIS AND APPLICATION OF REGI STUDIES ON THE SYNTHESIS AND APPLICATION OF REGI Abstract Three regioregular poly(3-alkylthiophenes) (P3ATs: P3HT, P3OT, and P3DDT) and six kinds of copolymers (PT-co-P3HTⅠ, P3HT-co-P3OTⅠ, P3HT-co-P3DDTⅠ, P3HT-co-P3DDTⅡ, P3MOT-co-P3DDT, and P3MOT-co-P3HT) have been synthesized successfully by Grignard metathesis. These poly(3-alkylthiophenes) and it’s copolymers, containing high percentage of head-to-tail coupling, can be easy of access a low energy, low space obstacle coplanar conformation, leading to highly conjugated character, better conductivity and optical property.
The physical properties of these polymers were done by NMR, FT-IR, GPC, XRD, UV, PL, DSC, and CV. The structure and regioregularity of P3ATs and copolymers were identified by NMR analysis. It is found that the regioregularity of all samples is larger than 90 %. The molecular weight of P3ATs and copolymers were 7702~8754 g/mol, and 7784~26671 g/mol, respectively. They exhibit a narrow molecular weight distribution (PDI = 1.22~2.14). The XRD results indicate that P3ATs and copolymers have a great order and crystalline structure. The UV-visible spectra of poly(3-alkylthiophenes) show that the λmax increases with increasing the level of regioregularity, resulting in the phenomena of red shift. λmax of P3ATs increases with increasing the length of the alkyl side chain resulting in the phenomena of blue shift. The conjugation length increases with increasing regioregularity and decreasing with increasing the lengths of alkyl side chain. However, the conjugation length increases with increasing the length of the alkyl side chain of copolymer. The bandgap of poly(3-alkylthiophene) and copolymers is about 1.8 eV. Besides, the poly(3-alkylthiophene) and copolymers emit yellow-orange light in CHCl3 solution measured by PL. The oxidation potential and the values of HOMO (5.01~5.42 eV) and LUMO (3.19~3.57 eV) can be calculated by the cyclic voltammetry. It is found that the Tm of P3ATs and copolymers decreases with increasing the length of the alkyl side chain.
The characteristics of organic thin-film transistor fabricated with P3ATs and copolymers acted as semiconducting materials have been carried out. The charge transport mobility and on/off current ratio of P3HT OTFT are 2.08 × 10–2 cm2/Vs and 9.74 × 103. The charge transport mobility and on/off current ratio of copolymers OTFT are 1.64 ×10–3 cm2/Vs, 8.36 × 103 (PT-co-P3HTⅠ), 8.96 × 10-3 cm2/Vs, 5.11 × 105 (P3HT-co-P3OTⅠ), 2.87 × 10–3 cm2/Vs, 7.52 × 103 (P3HT-co-P3DDT Ⅰ), and 9.57 × 10–3 cm2/Vs, 7.35 × 105 (P3HT-co-P3DDTⅡ) respectively. It is found that the characteristics of transistor increases with increasing the molecular weight of copolymers.
Advisor Committee Chin-Tsou Kuo - advisor
none - co-chair
none - co-chair
Files Date of Defense 2007-07-27 Date of Submission 2007-08-09