Femto- and picosecond fluorescence studies of solvation and non-radiative deactivation of ionic styryl dyes in liquid solution

A comparative study of the solvation and non-radiative relaxation dynamics of bridged and unbridged ionic styryl dye compounds is reported. Femto- and picosecond fluorescence transient measurements reveal solvation dynamics o n a picosecond timescale of the solutes in ethanol, benzonitrile and decano l. Bridging is found to strongly affect the lifetime of the emissive state. It is shown that the presence of unbridged styryl-group single bonds allow s for an effective non-radiative decay process. This decay process is suppr essed by double chemical bridging. (C) 2000 Elsevier Science B.V. All right s reserved.