Abstract
We used time-correlated single photon counting to investigate two photoinduced electron transfer dialkylsilylene-spaced donor-acceptor oligomers DA and DAD. The aniline is the electron Donor (D), trans-stilbene is the electron Acceptor (A) and SiMe2 as a spacer. We excited DA and DAD with a 266 nm laser beam. In non-polar solvents only the locally excited State (LE state) emits.The observed lifetimes, arranged from short to long are assigned to, the isomerization lifetime of trans-stilbene (τi) around 80-150 ps and the acceptor and donor fluorescence lifetime (τ0) are 1 ns and 4 ns. In slightly polar solvents, the LE state emission band displays three exponential decay. The observed lifetimes, arranged from short to long are assigned to, the formation of the charge transfer state lifetime (τLE→CT) is around 0.5-3 ps, the isomerization lifetime of trans-stilbene (τi) is around 70-210 ps and the acceptor and donor fluorescence lifetime (τ0) are 1 and 4 ns. In polar solvents, we detect the charge transfer state (CT state) emission. The observed lifetimes, arranged from short to long are assigned to, the lifetime of the formation of charge transfer state (τLE→CT) is ultrashort at zero timing, the decay lifetime (τDecay) is around 100-150 ps, the rise lifetime (τRise) is around 150-200 ps and the charge recombination lifetime (τRECT) is around 4-5.5 ns. τDecay and τRise are corresponding to the formation of the different intramolecular charge transfer states (ICT states) lifetimes. The experimental results imply the efficient charge transfer of DA and DAD in polar environments. DA and DAD are suitable for using in photoinduced electron transfer materials.