Structure-property relationships in light-emitting polymers:: Optical, electrochemical, and thermal studies

A series of new PPV-based alternating copolymers containing conjugated and nonconjugated blocks have been synthesized with the objective of raising the glass transition temperature (T-g)-relative to structures previously obtained. The higher T-g was achieved by inserting a more rigid unit in the spacer soft block. The effects of molecular architecture and chromophore substituents on the optical and redox properties of the polymers were investigated. The UV-vis absorption and emission in the solid state were in the range 360-415 and 455-533 nm, respectively. The calculated band gaps using cyclic voltammetry data were in the range 2.41-3.30 eV and were in good agreement with those calculated from the W-vis spectra edge. The results show that, through a choice of substituents and backbone structure, the emission color and other properties can be systematically varied.