Energy transfer in Rh 6G:Rh B system in PMMA matrix under cw laser excitation

Abstract

Energy transfer of Rh 6G:Rh B dye–mixtures in a poly methyl methacrylate (PMMA) matrix was studied by investigating the emission spectral characteristics under argon ion laser excitation. The fluorescence behaviour of the acceptor dye (Rh B) was investigated for various concentration of the donor (Rh 6G) and excitation powers. The energy transfer rate constants ( k f), transfer probability ( P da) and the transfer efficiency ( η) have been evaluated and their concentration dependence on donor molecules was studied. The observed decrement in the emission peak wavelength of the acceptor dye with donor concentration is attributed to the formation of complexes in the dye–mixture and also to the result of cross-relaxation taking place in the donor dye system. The blue shift in the emission wavelength of the acceptor was also investigated for various donor concentrations. A significant enhancement of fluorescence intensity of the acceptor (Rh B) of the order of 226% and a transfer efficiency of 90% were observed in the present dye–mixture system as compared with pure Rh B, both in PMMA matrices. Further the experimental results revealed the non-radiative type energy transfer for the dye system in the PMMA matrix.