Polyacetylene (CH)z is a simple conjugated polymeric system, the electrical behaviour of which is considerably modified by doping processes: from an insulating behaviour it successively becomes semi‐conducting and even metallic. In this work first the dopant profiles through the sample is measured and the macroscopic diffusion coefficients of iodine and SbF5 is deduced. In the second part of this work a model is proposed which simultaneously take into account the diffusion and a chemical fixation of dopant molecules along the polyacetylene fibrils. Comparison between experimental and computed results shows that this model allows a better comprehension of the observed phenomena than the simple diffusion laws.

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Optoelectrical properties of junctions electrochemically formed on the surface of n‐type CdTe single crystals are reported. The carrier transport process across the junction is controlled by tunnelling through the barrier from one side and by thermal emission followed by recombination at interface states from the opposite side of the junction. The CU characteristics have the shape typical for abrupt junctions and the built‐in potential UD = 1.1 V confirms the formation of an np homojunction covered by a thin Te film. The photovoltaic parameters of these cells are: open‐circuit voltage 0.42 V short‐circuit current density 0.5 to 0.8 mA/cm2, and fill factor 0.54. The spectral response indicate that the thin layer of Te acts only as an optical filter.

2014 Le dopage a permis de modifier considérablement les propriétés électriques du polyacétylène, et a été le point de départ de l'intérêt considérable porté à ce matériau depuis quelques années. Ce court article met en évidence l'existence d'un dopage inhomogène observé avec les dopants I2 et SbF5. Il montre en conséquence les risques d'erreur que ces inhomogénéités peuvent introduire lors de l'interprétation de certaines mesures physiques. Abstract 2014 By doping, the electrical behaviour of polyacetylene film was considerably modified leading to the large development of the research in the field of conducting polymers. The aim of this paper is to point out the inhomogeneity of the dopant through the film cross section, in particular with I2 and SbF5. It is also evidenced that errors may be induced by these inhomogeneities in the interpretation of physical measurements.