Light-emitting properties of stereoregular cis-rich poly(phenylacetylene)s

Absorption measurements of stereoregular poly(phenylacetylene)s (PPA) with controlled cis contents indicate that the lowest energy π–π* absorption band is due to the cis segments in the polymer chains and that the trans segments in the cis-rich PPAs may contain only a few repeat units. Both the photoluminescence (PL) efficiency and the PL lifetime of the PPAs in chloroform decrease with increasing cis concentration, for concentrations ranging from 67 to 100%. The relatively strong PL for 100% cis PPA suggests that the emission originates from the cis segments in the polymer chains rather than from the trans segments.