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Thin-film field-effect transistors (FETs) have been prepared using poly(3-hexylthiophene)/ arachidic acid and quinquethiophene/arachidic acid Langmuir–Blodgett (LB) films with thicknesses ranging from a monolayer to some ten monolayers. The effect of the number of layers on the mobility and conductivity has been studied. This is to our knowledge the first demonstration of a LB FET utilizing organic semiconductors as the active material.

Polarized electroluminescence (EL) from an oriented poly(3‐alkylthiophene) structure is reported, which is a first step towards the fabrication of an organic light‐emitting diode (LED) that emits polarized light. A multilayer structure is described that includes a Langmuir‐Blodgett film of poly(3‐decylmethoxythiophene), PDMT, in which the polyenic backbones are oriented along the dipping direction. The optical properties–absorption, EL, photoluminescence–and the I–V curve for an ITO/PDMT/Al device are presented.

Anisotropic field-effect mobility of pentacene thin-film transistor: Effect of rubbed self-assembled monolayer Appl.Field-effect mobility of polycrystalline tetrabenzoporphyrin thin-film transistors J. Appl. Phys. 98, 014503 (2005); 10.1063/1.1949713 Effects of order and disorder on fieldeffect mobilities measured in conjugated polymer thinfilm transistorsWe report the observation of photoluminescence quenching in thin films of poly (3hexylthiophene) and Langmuir-Blodgett films of poly (3-hexylthiophene) /arachidic acid by the injection of positive charges in the polymer. Charge injection was made in a polymer field effect transistor, used in what we name the luministor mode. The quenching is discussed in terms of polarons/bipolarons acting as recombination centra for the excitons, suppressing the photoluminescence. The inverse phenomenon, luminescence enhancement by depletion of charges, has also been achieved.

The purpose of the present study was to examine semiconductor properties of synthetic DOPA melanin, which are basic for future biological applications. DC conductivity, electron spin resonance (ESR), and atomic absorption spectroscopy (AAS) measurements have been performed to investigate the effect of Cu(2+)-ions on the semiconductor properties of melanin polymer synthesized from DOPA (3,4-dihydroxyphenylalanine). DOPA melanin - Cu2+ complexes examined show the decrease of both thermal activation energy delta Ea and pre-exponential factor sigma o values upon doping. At the same time no substantial changes in conductivity at 293 K have been observed. Formation of bipolaron states due to chelation of copper ions by melanin orthosemiquinones has been postulated. The Meyer-Neldel rule with a characteristic temperature T0 equal to 298 K and possible physiological implication of this fact are discussed. These data suggest, that DOPA melanin polymer could be useful as a type of culture substratum.