CONCENTRATION QUENCHING OF PHOTOLUMINESCENT RU(BPY)(3)(2+) DISPERSED IN A POLYSILOXANE FILM CONTAINING 2,2'-BIPYRIDINE PENDANT GROUPS IN DEPENDENCE OF MOLECULAR-DISTRIBUTION

The photoluminescent Ru(bpy)(3)(2+) complex was dispersed in a polysiloxane film containing 2,2'-bipyridine (bpy) pendant groups. The unusually long photoluminescence lifetime of the Ru(bpy)(3)(2+) (1,94 mu s at 25 degrees C) and the blue-shifted photoluminescent wavelength suggest a rigid polymer matrix. The fluorescence yield becomes lower with higher probe concentration, indicating concentration quenching. According to the analysis based on Stern-Volmer plots, the quenching obeys a mechanism composed of both static and dynamic processes. A statistical intermolecular distance distribution between the probes was used to interpret the results in terms of static and dynamic quenching. It is shown that in the present system the dispersed complexes diffuse slightly during the excited state.