Photoconductivity of poly

Another important problem of the photoconductivity of poly-N-vinylcarbazole is the carrier transport. With the so-called time of flight method this problem is well investigated. 

Fig. 23. Spectra photoconductivity of poly(p,p -diethynylazobenzene ]), the same after 10 min under ultraviolet irradiation (2) photoelectromotive force (3) absorption in diffuse reflection (4) [95]...

The photoconductivity of poly-p-xylylenes were investigated under various conditions [218-221]. The fundamental edge absorption of the polymers is at 300 nm. The photocurrents in the visual range of the spectra depended on the electrode nature. So it was interpreted as photoinjection of the charges from electrodes and separation of them at a Schottky type barrier. Suppression of hole injection for the plasma-treated polymer is related to the existence of an oxidized surface layer. 

The photoconductivity of poly[2-(N-carbazolyl)ethyl vinylether]91,92) and particularly of poly(N-acryloylcarbazole)91) is much inferior to that of PVK. In the case of the acrylic polymer the reported photocurrents are at least two orders of magnitude lower. The poor charge carrier generating efficiency is blamed for low photocurrents91 The relatively poor performance of the vinylether polymer is how ever attributed to charge carrier mobility92). 

Recently, Tanikawa et all94) discussed the photoconductivity of poly[i-( i-N-carbazolyethyl)-L-glutamate] and its charge transfer complex with 2,4,7, -trinitro-9-fluorenone. The photocurrents in this polymer are about one order of magnitude smaller than those of PVK at all measured wavelengths. The complex with TNF has a peak photocurrent at 600 nm while the absorption spectrum of the polymer... 

Very recently, the first metathesis reaction was utilized to synthesize a new type of photorefractive polymers, based on poly(1.6-heptadiyne) derivatives, that contain both a carbazole moiety as a hole transporter and NLO chromophores. attached to TT-conjugated backbones. Photorefractive polymers based on the previous works for the photoconductivity of poly(1.6-heptadiyne) derivatives containing a carbazole moiety and electrooptic activity of poly(1.6-heptadiyne) derivatives containing NLO chromophores were developed.Herein, all functional groups are covalently linked to the polymer backbone. 

This enhancement of the photoconductivity caused by Ceo doping may be ascribed the photoinduced electron transfer. We have reported that while the photoinduced electron transfer from polysilanes with alkyl substituents to C6o does not occur, the electron transfer from polysilanes with aromatic side groups (e.g. PMPS) to Ceo is effective [13]. Yoshino et al. have also reported that the photoconduction of poly(3-alkylthiophene) is remarkably enhanced upon doping [14]. Sariciftci et al. reported the similar photoinduced electron transfer in oligothiophene/C6o composite films [15]. Therefore, we believe that the photoinduced electron transfer occurs between ji-orbitals of the thienylene rings and those of C6o-... 

Damodare, L., T. Soga, and T. Mieno. 2003. Studies on dark and photoconductivities of poly [2-methoxy,5-(2 ethylhexyloxy)-p-phenylene vinylene] C6o thin films. pn J Appl Phys 42 2498. 

These dyes were then shown to sensitize photoconductivity of poly(N-vinyl carbazole). 

USGS. The delocalization of a electrons in polysilanes gives rise to unique electronic and optical properties. Also, several polysilanes have been foimd to function as useful thermal precursors to silicon carbide fibers and these materials have attracted attention with respect to microlithographic applications and as polymerization initiators (1,27,28). The use of these materials as hole transport layers in electroluminescent devices has also been explored (42). Indeed, the photoconductivity of poly(methylphenylsilane) doped with Geo has been studied and has been found to be comparable with the best materials available (43). 

Myachina et al. [298] reported on the photoconductivity of poly(l-vinyl-1,2,4-triazole) (42)... 

The photoconductivity of poly(3-alkylthiophenes) was found to be remarkably enhanced upon fiillerene... 

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