In situ measurements of the emission of secondary radiation from trans-polyacetylene during electrochemical p and n doping are reported. The luminescencelike emission was observed to be reversible with the doping and undoping process, and it was independent with respect to three different electrolyte systems: Li+ClO4- in sulfolane, Li+ClO4- in propylenecarbonate, and Li+BF4- in propylenecarbonate, which proves its origin from the polymer backbone. No reversible luminescence occurs during n doping. The intensity of the luminescence spectrum has a maximum for the laser excitation in the yellow green spectral region. The maximum position of the luminescence spectrum shifts by about 3000 cm-1 for a shift of the excitation energy of 7000 cm-1. The observed luminescence phenomena are explained by the polaron-doping mechanism in the disordered part of the sample and photoselective resonance process. A quantitative description is presented by calculating the energy for polaron levels by the Ḧckel method including geometry relaxation.
ASJC Scopus subject areas
- Condensed Matter Physics