Oligo- and Poly-Thiophenes Sample Clauses

Oligo- and Poly-Thiophenes. ‌ Polythiophene is among the most desiring organic materials because of its metal- like properties such as electrical conductivity upon doping, and tunable optical prop- erties which make polythiophenes potential candidates for organic field-effect transis- tors, organic light-emitting diodes, metal-/bio-sensors, etc. Armour et al. synthesized polythiophene in 1967 and measured the proton transferability of the trichloroacetic acid-protonated polythiophene in aprotic solutions.20 More research on the electri- cal properties of polythiophenes emerged in the early 1980s as the highly conduc- tive (0.02 ω1cm−1) poly(2,5-thiophenediyl)-arsenic pentafluoride complexes were ob- tained.21 The discovery of high thermal stability and low air/oxygen sensitivity of un- doped and oxidants, such as CF3SO3 – , doped polythiophene and poly-3-methylthiophenes derivatives encouraged researchers to explore more potential applications of polythio- phene.22 For example, polythiophene-based color switching devices have been devel- oped, and their kinetics studied.23 Yoshino Katsumi and coworkers initiated many ap- plications of polythiophene such as a fluorescent dye containing polythiophene bipolar thin film transistor with Ti/Au electrodes and Nylon coating, which shows promising effective carrier mobility and transconductance.24 More systematic studies and de- vice development carried out by Xxxxxxx XxXxxxxxxx and coworkers throughout the last two decades led polythiophene-based materials a significant step forward toward applications as organic electronics and product commercialization.25,26 While the satisfying thermal stability and electrical conductivity of polythiophene derivatives promote their functions as organic electronic devices, the shorter oligoth- iophenes (OT), with the number of thiophene units (n) between two to six, possess fascinating electronic structures such as adjustable HOMO-LUMO band gap, higher HOMO energy, and singlet-triplet state proximity. Experimental data, as well as com- putational approaches, show that the HOMO-LUMO band gap for oligothiophenes ranges from 4.09 eV (n = 2) to 2.72 eV (n = 6) and there is a loose linearly relationship between the inversed conjugation length and the band gap.27,28 A similar trend is also found in the relative electronic energy levels of oligothiophenes, where the dimer has a HOMO energy of 1.17 eV, tetramer 0.90 eV and hexamer 0.85 eV relative to Ag/AgCl reference electrode.29 The variable band gap energies an...