INHOMOGENEOUS DECAY KINETICS OF RU(BPY)(3)(2+) INCORPORATED INTO NAFION FILM

The photophysical properties of the Ru(bpy)(3)(2+) complex incorporate d into swelled Nafion membrane have been re-investigated with attentio n to the problem of partitioning of the luminescence complex between d ifferent microdomains of the membrane. The luminescence decay profiles obtained at different emission wavelengths and temperatures are studi ed by single curve, and global analysis methods, At low concentration of the probe in the membrane, the luminescence decay surface follows a biexponential law with normalized amplitudes strongly dependent on th e emission wavelength. The shorter lifetime component appears more sig nificantly in the high-energy part of the luminescence spectrum. The r ecovering of two average lifetimes obtained from global biexponential fitting indicates chat two major microdomains for the probe are in the membrane. The first one related to the short lifetime is ascribed to the fraction of probe embeded by the perfluorinated ether environment while the second microdomain is the heterogeneous water cluster interf ace which gives the long-lived lifetime component of the complex in Na fion. (C) 1998 Elsevier Science B.V. All rights reserved.