Transistor polyaniline

Fig. 7. Solid state molecular transistor based on polyaniline bridged microelectrodes. PVA layer of polyvinyl alcohol 1 drain current Vg gate voltage rendering the polyaniline non-conductive Vg gate voltage switching on conductivity of the polyaniline layer (from ref.

The bridging polymer is a conducting poly(3-methyIthiophene) or polyaniline and the solid state redox conduction between all electrodes is accomplished by a common coating with poly(ethyleneoxide)/Li" CF3S03- or poly(vinyl alcohol)/ The polyaniline based molecular transistor proved as a very sensitive moisture detector it works well in a dry argon atmosphere but in water saturated argon the device cuts out... 

B3 is a short notation for V..V -diphenyl-1.4-phcnylcncdiaininc. which is known also as phenyl-end-capped-dimer" of the polyaniline chain [26], B3 consists of three phenyl (benzene-like) rings connected by C-N links as shown in Fig. 1. The interest in this molecule was stimulated by its luminescence properties [27] as well as by the potential applications in the field-effect transistors [28],... 

Several polymer conductors are commercially available, and have been used in the demonstration of printed transistors. These include PEDOT PSS, which is a commercially available polymer conductor, as well as various versions of polyaniline. The latter is typically doped with an acid or salt to increase conductivity. Both of these material systems are water soluble and easily printable. They also typically form good interfaces to organic semiconductors, making them attractive for use in printed transistors. As with polymer dielectrics, however, it is important to note that their usability with inorganic semiconductors is questionable, of course. 

Fig. 13. Microelectrochemical device, (a) Schematic illustration of the microelectrochemical transistor based on polyaniline (thickness of the polyaniline layer 5 pm, electrode width 1-2 pm, distance 2-4 pm) (b) characteristic curve of the polyaniline transistor (Id versus Vg at Vd = 0.18 V). (Redrawn from Wrighton, 1986).

K. S. Lee et al.. High-resolution characterization of pentacene-polyaniline interfaces in thin-fihn transistors, submitted to Adv. Funct Mater., 16, 2409, 2006. 

N. J. Pinto, A. T. Johnson, Jr., A. G. MacDiarmid, C. H. MueUer, N. Theofylaktos, D. C. Robinson, and F. A. Miranda, Electrospun polyaniline/polyethylene oxide nanofiber field-effect transistor, Appl. Phys. Lett., 83, 4244—4246 (2003). 

K. C. Aw, N. T. Salim, H. Peng, L. Zhang, J. Travas-Sejdic, and W. Gao, PN-junction diode behavior based on polyaniline nanotuhes field effect transistor, J. Mater. Sci.- Mater. Electron., 19, 996-999 (2008). 

Wrighton and co-workers developed a "molecule-based transistor" which uses conducting polymers either chemically doped polyaniline layers deposited atop Au interdigitated electrodes [44] or on 50-100 nm "gate" polyaniline polymer between two Au electrodes shadowed with Si02 this device still has a rather slow switching rate (10 kHz) and a gain of almost 1,000 [45]. The related work of Stubb and co-workers is discussed elsewhere in this volume. 

It has been known since the early stage of conducting polymer research that polyandine fibrils of 100 nm in diameter can naturally form on the surface of an electrode [4,40-45] with a compact microspheriod underlayer. Some recent work demonstrates that pure polyaniline nanofibers can be obtained without the need for any template by controlling the polymerization rate [46—48]. Although this process is not readily scalable from a materials point of view, such work could be very important for making functional devices, since nanofiber-coated electrodes can be used as a platform to fabricate sensors and transistors. Interconnected network-like structures with polyaniline nanoKnkers 10-50 nm wide have also been identified in polymer blends [49-51]. 

Pinto, N.J., et al. 2003. Electrospun polyaniline/polyethylene oxide nanofiber field-effect transistor. 

Barker, P.S., A.P. Monkman, M.C. Petty, and R. Pride. 1997. A polyaniline/silicon hybrid field effect transistor humidity sensor. Synth Met 85 1365. 

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