Synthesis and electrical properties of novel oligothiophenes partially containing 3,4-ethylenedioxythiophenes

Abstract

Five sorts of soluble oligothiophenes (trimer to undecamer) containing 3,4-ethylenedioxythiophene (EDOT) were synthesized, and their optical and electrochemical properties were investigated in relation to the chain length of oligothiophenes and the number of EDOT units. The introduction of the EDOT unit into a main oligothienylene unit induced a red shift of absorption bands and a negative shift of oxidation potentials.The conductivity of an electrochemically oxidized film of undecamer was found to be around 1 S cm À1 .A thin-film field effect transistor was preliminary fabricated with neutral undecamer films and the hole mobility was determined.

In situ conductivity measurements of polythiophene partially containing 3,4-ethylenedioxythiophene and 3-hexylthiophene

“…Compared with H5T, the absorption band of HE5T was red-shifted by 17 nm. This is well consisted with the previous report in which we have found that the introduction of the EDOT units into a main oligothienylene unit induced a red-shift of absorption bands [33]. The absorption band of polyHE5T was much more red-shifted than that of HE5T due to the expansion of effective π-conjugation length by the polymerization.…”

“…In order to investigate the electrical properties of polyHE5T in detail, doping levels and electrical conductivities were measured in the potential range between [24,[26][27][28][29][30][31][32][33]. Figure 5a depicts semilogarithmic plots of doping level against electrode potential for the polyHE5T film.…”

“…In situ conductivity measurements were made in acetonitrile solution of TEAP (0.1 mol dm −3 ) by the two-probe method [24,[26][27][28][29][30][31][32][33]. A solution of polyHE5T in o-dichlorobenzene (50 μL, 20 mg mL −1 ) was spin-coated (500 rpm for 5 s, then 2,000 rpm for 30 s) on a micro-array Pt electrode (ALS Co., Ltd., 65 lines, separation distance = 5 μm, total width = 260 mm).…”

Synthesis and Properties of Donor-acceptor-type Polymers Comprising Alkoxy-substituted Bithiophene Units

“…We have previously reported the synthesis of a series of oligothiophenes with well-defined structures and investigated their optical, electrochemical, and electrical properties [20][21][22][23][24]. These studies revealed that the electronic properties of oligothiophenes can be tuned easily and systematically by adjusting their chemical structures.…”

“…These studies revealed that the electronic properties of oligothiophenes can be tuned easily and systematically by adjusting their chemical structures. For example, increasing the chain lengths of the oligothiophenes and introducing ethylenedioxy groups at the β-position of the thiophene rings causes a red-shift in the optical absorption bands and a negative shift in the oxidation potentials [22].…”