Polyalkylthiophene-based photodetector devices: effect of side-chain length on the device performance

The photoresponse of Schottky-type junctions between aluminium and poly(3-alkylthiophenes) with different length of the alkyl-chain was investigated. Better results were obtained with the junctions based on the polymers with shorter side-chains, though the absorption spectra reveal an increasing conjugation length with the length of the alkyl-chain. The trend of the photoresponse was explained by taking into account the effect of the substituents on the morphology of these materials.