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A general method is proposed to produce oriented and highly crystalline conducting polymer layers. It combines the controlled orientation/crystallization of polymer films by high-temperature rubbing with a soft-doping method based on spin-coating a solution of dopants in an orthogonal solvent. Doping rubbed films of regioregular poly(3-alkylthiophene)s and poly(2,5-bis(3-dodecylthiophen-2-yl)thieno[3,2- b]thiophene) with 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ) yields highly oriented conducting polymer films that display polarized UV-visible-near-infrared (NIR) absorption, anisotropy in charge transport, and thermoelectric properties. Transmission electron microscopy and polarized UV-vis-NIR spectroscopy help understand and clarify the structure of the films and the doping mechanism. F4TCNQ− anions are incorporated into the layers of side chains and orient with their long molecular axis perpendicular to the polymer chains. The ordering of dopant molecules depends closely on the length and packing of the alkyl side chains. Increasing the dopant concentration results in a continuous variation of unit cell parameters of the doped phase. The high orientation results in anisotropic charge conductivity (σ) and thermoelectric properties that are both enhanced in the direction of the polymer chains (σ = 22 ± 5 S cm−1 and S = 60 ± 2 µV K−1). The method of fabrication of such highly oriented conducting polymer films is versatile and is applicable to a large palette of semiconducting polymers. [ABSTRACT FROM AUTHOR]

In this article we highlight the importance of film deposition conditions on the electrochemical behaviour of the work horse of the organic electronics community, namely poly(3-hexylthiophene) (P3HT). While a huge number of publications have dealt with the influence of morphology on optical, electronic and opto-electronic properties, the effect on the electrochemical response has been less addressed. Electrochemistry is often only used as convenient tool in this community to determine the energy levels or more specifically the HOMO level of P3HT. This is performed by measuring oxidation onset potentials and introducing correction factors which relate the electrochemical with the Fermi scale. Here we want to stress out that this procedure should be performed with great care in order to get meaningful data. We demonstrate that film deposition conditions can strongly alter the oxidation behaviour of the polymers which makes the determination of the oxidation onset potentials and energy levels very difficult. We compare state-of-the-art of electropolymerisation and solution deposition of chemically synthesized polymers of defined regioregularity with our own expertise on deposition and controlling crystallisation in films. [ABSTRACT FROM AUTHOR]