Photoluminescence studies of solution thermochromism in a cyano-subsituted phenylene vinylene derivative

Time-resolved and steady-state photoluminescence (PL) studies of a cyano-substituted poly(phenylene vinylene) (CNPPV) in toluene solution are reported as a function of temperature. On reducing temperature there is no evidence for the formation of aggregates, with both the absorption and emission properties revealing only a moderate increase in the average length of conjugation. Time-resolved anisotropy data reveal a single rotational correlation time of six nanoseconds. These data are consistent with a very low molecular weight polymer sample that behaves in a molecular fashion.