Thin films of the metallopolymer [Os(bpy)2 (PVP)10]2+, where bpy is 2,2'-dipyridyl and PVP is poly(4-vinylpyridine), luminesce at 750±12 nm upon excitation at 355nm. The luminescence decay responses can be described by a double exponential decay model in which the limiting lifetimes are 75±14 (population fraction of 0.9) and 35±8 ns (population fraction of 0.1) for films in contact with aqueous 0.1 M H2SO4. Electrochemistry has been used to create well defined concentrations of the luminescence quencher, Os3+, within the films. Time resolved spectroscopy reveals that both dynamic and static processes contribute to luminescence quenching with a rate constant for electron transfer between the photoexcited Os2+* and the Os3+ centres of 1.3x107 M-1s-1 being observed. Stable gold nanoparticles have been created within the metallopolymer by the chemical reduction of tetrachloroaurate. These nanocomposite materials exhibit enhanced emission intensity compared to the gold free films.
|