Solvent effects on the luminescent properties of conjugated molecules

The photoluminescent yield and lifetime of 2,5-dioctyl-p-distyrylbenzene is shown to vary significantly in a range of organic solvents. This variation is seen to correlate well with the overlap of the vibrational spectrum of the molecule with that of the solvent. This overlap is proposed as a gauge of the nonradiative decay processes in dilute solution. In solutions of hig her concentration and of the polymer PmPV, this correlation is lost, howeve r. The loss of correlation is attributed to a departure from single molecul ar photophysics as a result of aggregation.