Regioregular polythiophenes

Liu, J., Sheina, E., Kowalewski, T. and McCullough, R. D. (2002) Tuning the electrical conductivity and self-assembly of regioregular polythiophene by block... 

Bao, Z. Lovinger, A. 1999. Soluble regioregular polythiophene derivatives as semiconducting materials for thin film field-effect transistors. Chem. Mater. 11 2607-2612. 

Ong, B. Wu, Y. Liu, P. 2005. Design of high-performance regioregular polythiophenes for organic thin-film transistors. Proc. IEEE 93 1412-1419. 

FIGURE 2.26 PL and absorption spectra of thin films of regioregular polythiophenes HT-396 (a) and HHTT-396 (b), spin coated on a fused silica substrate. (From Barta, P., Cacialli, F., Friend, R.H., and Zagorska, M., J. Appl. Phys., 84, 6279, 1998. With permission.)... 

R.D. McCullough, P.C. Ewbank, and R.S. Loewe, Self-assembly and disassembly of regioregular, water soluble polythiophenes chemoselective ionchromatic sensing in water, J. Am. Chem. Soc., 119 633-634, 1997. 

R.E. Gill, G.G. Malliaras, J. Wildeman, and G. Hadziioannou, Tuning of photo- and electroluminescence in alkylated polythiophenes with well-defined regioregularity, Adv. Mater., 6 132-135, 1994. 

M.R. Andersson, W. Mammo, T. Olinga, M. Svensson, M. Theander, andO. Inganas, Synthesis of regioregular phenyl substituted polythiophenes with FeCl3, Synth. Met., 101 11-12, 1999. 

Xue C, Cai F, Liu H (2008) Ultrasensitive fluorescent responses of water-soluble, zwitter-ionic, boronic acid-bearing, regioregular head-to-tail polythiophene to biological species. ChemEur J 14 1648-1653... 

Levesque I, Leclerc M (1996) Ionochromic and thermochromic phenomena in a regioregular polythiophene derivative bearing oligo(oxyethylene) side chains. Chem Mater 8 2843-2849... 

Paid K, Leclerc M. Functionalized regioregular polythiophenes towards the development of biochromic sensors. Chem Commun 1996 2761-2762. 

A similar absorption bands have been reported for a regioregular P3HT pristine film by continuous wave photoinduced absorption (PIA) measurements at 10 K. The PIA spectrum exhibits an absorption peak around 990 nm and was assigned to localized polarons in the disordered portions of the film. Similar rapid decays were observed for the other polythiophene pristine films. Thus, these rapid decays are ascribed to the charge recombination of polaron pairs formed in the pristine film. 

Regioregular polythiophenes with various side chains containing ether, ester, and thiol units had been synthesized, and showed interesting properties [330]. However, the polydispersity of these polymers was not con-... 

Fig. 4.5. Schematic representation of the lamellar formation of a regioregular polythiophene system via intermolecular side-chain interdigitation.

Molecular self-organization in solution depends critically on molecular structural features and on concentration. Molecular self-organization or aggregation in solution occurs at the critical saturation concentration when the solvency of the medium is reduced. This can be achieved by solvent evaporation, reduced temperature, addition of a nonsolvent, or a combination of all these factors. Solvato-chromism and thermochromism of conjugated polymers such as regioregular polythiophenes are two illustrative examples, respectively, of solubility and temperature effects [43-45]. It should therefore be possible to use these solution phenomena to pre-establish desirable molecular organization in the semiconductor materials before deposition. Our studies of the molecular self-assembly behavior of PQT-12, which leads to the preparation of structurally ordered semiconductor nanopartides [46], will be described. These PQT-12 nanopartides have consistently provided excellent FETcharacteristics for solution-processed OTFTs, irrespective of deposition methods. 

Regioregular poly(3-alkylthiophene)s have received a lot of attention, especially because of their high electrical conductivities in the doped state, and because of their unusual solvatochromic and thermochromic behavior . Hence, a lot of research has been focused on clarifying the structure of these materials, both in the solid state and in solution. Today, it is agreed that supramolecular aggregation of polythiophene chains plays an important role in their physical properties. 

---