Dithieno thiophene polymer

Many substituted thiophenes have also been electrochemically polymerised [19,54,399-405] (Table 4) as have thiophene dimers [21,37,55,251,400,406], trimers [21, 83,407], and tetramers [256,406], with the thiophene dimer giving rise to higher quality films than does the monomer [37, 395,408]. Several polycyclic monomers including a thiophene ring have also been polymerised [408-416], as have a series of compounds consisting of two thiophene rings linked by a polyene chain (Fig. 23c). The polymerisation of dithieno-thiophene (Fig. 23d) results in a polymer which shows remarkable similarity to polythiophene in its properties [409,410,414],... 

S. Luzzati, M. Basso, M. Catellani, C. J. Brabec, D. Gebeyehu and N. S. Sariciftci, Photo-induced electron transfer from a dithieno thiophene-based polymer to Ti02, Thin Solid Films, 403, 52-56 (2002). 

Thus, many polymers with different conductivity were synthesized. To cite a few, these are polythiophene [158], 3-methylthiophene [159], polymers of 3-thiophene-acetic acid and methyl 3-thiophene-acetate [160], poly(2,5-thienylenevinylene) [161], poly(benzo[h]-thiophene) [162], poly(naphto[2,3-c]thio-phene) [163], poly(dithieno[3,2-h 2, 3 -fii]-thiophene) [164], poly(3- -hexylthiophene)... 

The polymers of 4H-cyclopenta[2,l-b 3,4-//Jdi thiophene derivatives showed absorptions in the range 560-590 nm [03MM2705]. Some monomers are based on the nonaromatic (12 n electrons) 4H-cyclopenta[2,l-fr 3,4-l/]dithiophen-4-yl cation 580a (X = CH+) model which was expected to display a reduced HOMO-LUMO separation, compared to related aromatic fused systems (i.e., 580, X = S, O, NF1) (91JCS(CC)752). Polymers of 580 (X = S) showed absorption at 480 nm. Poly(dithieno[3,4-b 3, 4 -4J thiophene) showed an absorption at 590-610 nm (89SM(28)C507 97MI23). 

The synthesis, characterization, electrical conductivity, and field effect mobility of a series of novel soluble N-alkyl dithieno[3,2-b 2, 3 -d]pyrrole (DTP) and thiophene (TH)-based copolymers (DTP-co-THs) were reported (06MM1771 08JA13167). The incorporation of DTP units extends n conjugation, and the introduction of thiophene subunits imparts good solubility, high conductivity, and high charge carrier mobility. Therefore, the incorporation of DTP units and various substituted thiophenes into the polymer backbone affords the ability to enhance the solubility, lower the band gap, and achieve the enhanced electronic properties. 

Fig. 10.24 Structures of polymers absorbing beyond 600 nm (a) poly(dithieno(3,4-b 2, 3 -d)thiophene), (b) tbiophene/isothianaphthalene copolymers, and (c) a thienyl-pyrrole/benzothiazole copolymer.

Figure 9 shows the discharge curves of a Type I polypyrrole-based, a Type II polypyrrole/poly(3-methylthiophene)-based and a Type III poly(dithieno[3,4-6 3, 4 -d]thiophene-based supercapacitor at 4 mA cm discharge current. Types I and II can be assembled using such conventional heterocyclic polymers as polypyrrole, polyaniline and polythiophene, which are efficiently p-dopable polymers and can easily be chemically or electrochemically synthesized from inexpensive... 

Much like PITN and its analogs, various fused thienothiophenes have also found interest as potential precursors for low handgap systems (Chart 12.9). One of the early systems of promise were polymers of dithieno[3,4- 3, 4 -d thiophene (69), initially reported in 1988 hy Tahani and coworkers [91-93] to have an g of 1.1 eV (for a relevant discussion of prior work see Ref. [1]). Since 1995, however, a numher of new reports on poly(dithieno[3,4-( 3, 4 -d]thiophene) (69) have appeared. 

The remaining isomeric dithienothiophenes, poly(dithieno]3,4-b 3, 2 -d]thiophene) (70) and poly(dithieno]3,4-b 2, 3 -d]thiophene) (71), have also been the subject of a number of studies since their initial preparation in 1997 [106]. As with polymer 69, polymers 70 and 71 were prepared by electropolymerization of the corresponding monomeric dithienothiophenes to give films, which undergo both n- and p-doping processes. 

Taliani, C., et al. 1989. Optical properties of a low energy gap conduction polymer Poly-dithieno [3,4-b 3, 4 -d] thiophene. Synth Met 28 C507. 

Quattrocchi, C., et al. 1993. Theoretical investigation of the structure and electronic properties of poly(dithieno[3,4-fc3, 4 -d]thiophene), a small-band-gap conjugated polymer. Macromolecules 26 1260. 

Arbizzani, C., M. Catellani, M. Mastragostino, and C. Mingazzini. 1995. N- and p-doped poly-dithieno[3,4-B 3, 4 -D] thiophene A narrow band gap polymer for redox supercapacitors. Electro-chim Acta 40 1871-1876. 

Polythienothiophenes. Thieno[2,3-6]thiophene [633], thieno[3,2-b]thiophene [634], dithieno[3,2-6 2, 3 -rf]thiophene [635], and the corresponding electrogenerated polymers have all been investigated [636-639] (Fig. 28). Contrary to theoretical expectations. 

Dithieno[3,4-6 3, 4 -polymerized electrochemically [640,644- ] or photochemically [647]. The polymer seems to be transparent in the visible spectral region in its doped form, while the low-energy absorption edge of the im-doped neutral state indicates a bandgap of 1.1-1.2 eV [648]. 

Synthesis of Polymers Containing Dithieno[3 - 2 -[Pg.189]

Prototypes of such supercapadtors of small geometric areas have been developed [126, 127]. 3-MethylPT and poly(dithieno[3,4-b 3, 4 -d]thiophene) have been grown galvanostatically on carbon paper electrodes by electrochemical polymerization of the appropriate monomers. The properties of studied supercapacitors with these materials are comparable to common carbon supercapadtors in the case of the first mentioned polymer and appear to be better in the case of the second polymer [125]. 

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