3-octylthiophene

The evolution of the XPS C(ls), S(2p), and Al(2p) core level lines, upon A1 deposition onto poly(3-octylthiophene) films (P30T), is shown in Figure 5-15 [84. The S(2p) spectrum for the pristine polymer consists of two components, S(2p 1/2) and S(2p.v2), due to spin-orbit coupling. 

Deen, M. Kazemeini, M. 2005. Photosensitive polymer thin-film FETs based on poly(3-octylthiophene). Proc. IEEE 93 1312-1320. 

D Braun, G Gustafsson, D McBranch, and AJ Heeger, Electroluminescence and electrical transport in poly(3-octylthiophene) diodes, J. Appl. Phys., 70 564—568, 1992. 

B. Kraabel, D. Moses, and A.J. Heeger, Direct observation of the intersystem crossing in poly(3-octylthiophene), J. Chem. Phys., 103 5102-5108, 1995. 

S. Guillerez and G. Bidan, New convenient synthesis of highly regioregular poly(3-octylthiophene) based on the Suzuki coupling reaction, Synth. Met., 93 123-126, 1998. 

The QD-MWNT hybrid structures were formed via the assembly of quantum dot (QD) on the surface of MWNTs in aqueous solution (Jares-Erijman and Jovin, 2003), which shows an excellent solubility in aqueous solution, and owns potential application in bioassay, bio-conjugation, and biosensors as well as solar cell. For example, incorporation of QDs and SWNTs into the poly(3-octylthiophene)-(P3OT)... 

Polypyrrole was the first conducting polymer used as ion-to-electron transducer in solid-state ISEs [43], and is still one of the most frequently used [45-68]. Other conducting polymers that have been applied as ion-to-electron transducers in solid-state ISEs include poly(l-hexyl-3,4-dimethylpyrrole) [69,70], poly(3-octylthiophene) [44,70-74], poly(3,4-ethylenedioxythiophene) [75-86], poly(3-methylthiophene) [87], polyaniline [44,67,73,88-99], polyindole [100,101], poly(a-naphthylamine) [102], poly(o-anisidine) [67] and poly(o-aminophenol) [103], The monomer structures are shown in Fig. 4.1. 

Solid-state ISEs with conducting polymers are also promising for low-concentration measurements [60,63,74], even below nanomolar concentrations [60,74], which gives rise to optimism concerning future applications of such electrodes. In principle, the detection limit can be improved by reducing the flux of primary ions from the ion-selective membrane (or conducting polymer) to the sample solution, e.g., via com-plexation of primary ions in the solid-contact material. For example, a solid-state Pb2+-ISEs with poly(3-octylthiophene) as ion-to-electron transducer coated with an ion-selective membrane based on poly(methyl methacrylate)/poly(decyl methacrylate) was found to show detection limits in the subnanomolar range and a faster response at low concentrations than the liquid-contact ISE [74]. 

Whereas in solution the photoluminescence efficiency (Of) of poly(3-alkylthiophenes) (PATs) is 3(Mf)%, it drastically drops to 1-4% and lower in the solid state due to the increased contribution of nonradiative decay via interchain interactions and ISC caused by the heavy-atom effect of sulfur (97MM4608). Optoelectronic devices of this type of compounds have been studied (98SCI(280)1741 06SM(156)1241). Fibers of poly(3-hex-ylthiophene) for photovoltaic applications have been described (07MI1377). Poly(3-octylthiophene) showed a TTA band at 800 nm (96JPC15309). The photophysical properties of some alkyl and aryl polythiophenes have been studied (03JCP(118)1550). The absorption maximum of poly(3-octylthiophene) is at 438 nm, while the fluorescence was... 

The conjugation length of poly(3-alkylthiophene)s can be determined from the absorption maximum in the electronic spectrum. Whereas regioregular (i.e., head-tail) poy(3-octylthiophene) (POT) displays a maximum at 442 nm in CHCl3/Freon-113 solution, the absorbance maximum of 504 is blue shifted by 114 to 328 nm. This blue shift could arise from a particularly low molecular weight. 

The electronic effect of perfluoroalkyl substituents on the absorption spectra of arenes is relatively small (e.g., Xmax 3-perfluorooctylthiophe-ne = 229 nm 3-octylthiophene = 235 nm). Thus, the anomalously low absorption maximum of 504 is the effect of twisting around the backbone. It is apparent that the difference in size of the side chains is sufficiently large to cause twisting of the conjugated backbone of 504 due to steric interactions between the perfluoroalkyl substituents and the adjacent repeat unit. 504 exhibits green fluorescence (Xmax = 512 nm) in solution with a maximum blue shifted by 58 nm relative to POT (570 nm). Accordingly, 504 shows a Stokes shift of ca. 1.4 eV (186 nm) compared to only 0.6 eV (126 nm) for POT. 

Copolymer between 3-octylthiophene and 3-decyloxythiophene has been described (06JA8980). They showed an absorption band at 538 nm in chloroform and at 621 nm in film, with a bandgap of 1.64 eV. 

Photophysical and electron transfer properties have been studied also in poly(3-octylthiophene) linked to Ru(II) and Os(II)-bypyridine (00IC5496). 

Several organics, e.g. pristine poly(3-octylthiophene), polyfluorene, bifunctional spiro compounds and polyphenyleneethynylene derivative, have been used for fabricating photOFETs. Responsivity as high as 0.5-1 A/W has been achieved in some of these transistors. We have already discussed the bulk heterojunction concept in Chapter 5. The bulk heterojunctions are fabricated using acceptor materials with high electron affinity (such as C<5o or soluble derivatives of C6o) mixed with conjugated polymers as electron donors. PhotOFETs based on conjugated polymer/fullerene blends are expected to show... 

Giorgetti E, Margheri G, Del Rosso T, Sottini S, Muniz-Miranda M, Innocenti M (2004) A study of the degradation of poly(3-octylthiophene)-based light emitting diodes by surface enhanced Raman scattering. Appl Phys B 79 603-609... 

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