Poly thienylenevinylenes

More recently, Leclerc and co-workers synthesized (2,7-carbazolylenevinylene)-a/f-(thienylenevinylene) copolymer 69 via the Horner-Emmons reaction [111]. Whereas this material showed red emission in solution (kpL = 581 nm, pl = 16 %), it was not fluorescent in the solid state. 

Attaching a cyano group drastically improves the fluorescence of PTV materials. Two CN-PTV derivatives, 71 and 72, synthesized by the Knoevenagel method, showed strong fluorescence in the NIR region and have been used to fabricate the rare NIR PLEDs [110]. 

Combining the CN-PTV structure with other conjugated moieties allows one to tune the emission and to achieve a deep-red color. A PLED based on fluorene-PTV copolymer 73 (ITO/LiF/73/PBD/LiF/Al/Ag) emitted red-orange light (brightness 45 cdm at 10 V turn-on voltage 5 V) [161]. Pure red emission was also achieved in a similar copolymer 74 [163]. 

---

A representative example for the information extracted from a TRMC experiment is the work of Prins et al. [141] on the electron and hole dynamics on isolated chains of solution-processable poly(thienylenevinylene) (PTV) derivatives in dilute solution. The mobility of both electrons and holes as well as the kinetics of their bimolecular recombination have been monitored by a 34-GHz microwave field. It was found that at room temperature both electrons and holes have high intrachain mobilities of fi = 0.23 0.04 cm A s and = 0.38 0.02 cm / V s V The electrons become trapped at defects or impurities within 4 ps while no trapping was observed for holes. The essential results are (1) that the trap-free mobilities of electrons and holes are comparable and (2) that the intra-chain hole mobility in PTV is about three orders of magnitude larger than the macroscopic hole mobility measured in PTV devices [142]. This proves that the mobilities inferred from ToF and FET experiments are limited by inter-chain hopping, in addition to possible trapping events. It also confirms the notion that there is no reason why electron and hole mobilities should be principally different. The fact... 

Prins P, Candeias LP, van Breemen AJJM, Sweelssen J, Herwig PT, Schoo HFM, Siebbeles LDA (2005) Electron and hole dynamics on isolated chains of a solution-processable poly (thienylenevinylene) derivative in dilute solution. Adv Mater 17 718... 

SCHEME 12.25 Routes to alkoxy-fiinctionalized poly(thienylenevinylene)s. 

TABLE 12.4 Solid State Absorption, Bandgaps, and Conductivities for Poly(thienylenevinylene)s... 

Goldoni, R, R.A.J. Janssen, and E.W. Meijer. 1999. Synthesis and characterization of new copolymers of thiophene and vinylene Poly(thienylenevinylene)s and poly(terthienylenevinylene)s with thioether side chains. / Polym Sci A 37 4629-4639. 

R. Toyoshima, K. Akagi, H. Shirakawa, Syntheses and properties of poly(thienylenevinylene) derivatives with hexyl groups, Synth. Met., 84, 431-432 (1997). 

I. Osaka, H. Goto, K. Itoh, K. Akagi, Dichroic fluorescence of liquid crystalline polythiophene and poly-thienylenevinylene derivatives, Synth. Met., 119, 541-542 (2001). 

Another useful approach to attaining good solubility is to start from processable prepolymers. After being processed, these prepolymers can be converted into conductive form through, for example, thermosetting. This method was applied to syntheses of poly(p-phenylene) [46], poly(thienylenevinylene) [47], etc. as final forms. 

The synthesis of long alkylsilyl-substituted poly(thienylenevinylene) PSiTV (Fig. 36) via heteroaromatic dehydrohalogenation polymerization was reported by Shim et al. [149]. The polymer was determined to have a molecular weight of... 

Lee YB, Shim HK, Ko SW (2003) SUyl-substituted poly(thienylenevinylene) via heteroaromatic dehydrohalogenation polymerization. Macromol Rapid Commun 24 522-526... 

Kim J, Lim B, Baeg KJ, Noh YY, Khim D, Jeong HG, Yun JM, Kim DY (2011) Highly soluble poly(thienylenevinylene) derivatives with charge carrier mobility exceeding 1 cm V s. Chem Mater 23 4663 665... 

---