Polythiophene/insulating polymer composites

Thin-Film Transistors Based on Polythiophene/insulating Polymer Composites... 

I 9 Enhanced Electrical Conductivity of Polythiophene/Insulating Polymer Composite... 

Lu G, Tang H, Qu Y, Li L, Yang X (2007) Enhanced electrical conductivity of highly crystalline polythiophene/insulating-polymer composite. Macromolecules 40 6579-6584... 

Intercalation of electroactive polymers such as polyaniline and polypyrrole in mica-type layered silicates leads to metal-insulator nanocomposites. The conductivity of these nanocomposites in the form of films is highly anisotropic, with the in-plane conductivity 10 to 10 times higher than the conductivity in the direction perpendicular to the film. Conductive polymer/oxide bronze nanocomposites have been prepared by intercalating polythiophene in V2O5 layered phase, which is analogous to clays. °° Studies of these composites are expected not only to provide a fundamental understanding of the conduction mechanism in the polymers, but also to lead to diverse electrical and optical properties. 

The applications of the soluble polythiophene derivatives to the PLED are advantageous in that their polymer blends or composites can be easily formed [147]. Berggren et al. [126] have recently reported that these polymer blends (e.g. a mixture of different kinds of polythiophene derivatives) exhibit voltage controlled colors in electroluminescence. This effect was explained by the assumption that a number of nano-PLEDs of 50-200 nm in size yielded by micro phase separation are coupled parallel and operate in a specific voltage range depending upon the polymer species [126,130,131]. In addition, these nano-PLEDs dispersed in an insulator matrix such as poly(methyl methacrylate) display white hght emission with quantum efficiency ofO.4-0.6% [133]. 

The optical and electronic properties of blends of soluble polythiophene derivatives and polystyrene (PSt) were investigated over the full range of compositions. The polyblend films, made conducting by charge transfer doping (reaction with NOPFe in acetonitrile) display an insulator-metal transition at the percolation threshold a volume fraction of 16% conducting polymer in PSt. 

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