Resolving the radical cation formation from the lowest-excited singlet (S-1) state of terthiophene in a TiO2-SiO2 hybrid polymer matrix

Photoexcitation dynamics of terthiophene (3T) molecules incorporated in an organic-inorganic matrix containing titanium in the network are investigated by polarized transient absorption with femtosecond time resolution. We observed the decay of excited-state absorption of neutral 3T and simultaneous rise of 3T(-)(+.) radical cation absorption. The observed kinetics of electron transfer are independent of excess vibrational energy in the S-1 state, and can be described by a biexponential function with time constants of similar to 1 ps (for similar to 62% of the excited 3T molecules) and similar to 8 ps (for similar to 33%). The angle between the S-1