We developed an alternative approach to produce self-assembled (SA) thin films of poly(p-phenylene vinylene) (PPV) by controlled substitution of the chloride counterion of the precursor poly(xylylidene tetrahydrothiophenium chloride) (PTHT) by a long chain dodecylbenzenesulfonate (DBS) anion. The main advantage of this novel procedure is that thermal conversion through the elimination of DBS may be performed at considerably lower temperatures (80-100 °C) in few minutes. In addition it provides PPV films with better optical properties and low incorporation of structural defects, like carbonyl groups. An important feature of these SA-PPV films is the well resolved vibronic structures in the photoluminescence and absorption spectra. We observe a dramatic improvement in quantum efficiency of PPV when the conversion temperature is decreased from 230 to 80 °C. This effect may be explained by the decrease of extrinsic defect incorporations (carbonyl groups) detected by infrared (IR) measurements. This improvement in the optical properties at low temperatures may help us to understand basic phenomena, such as the nature of excitons in PPVs.
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