Photoinduced vibrational absorptions from poly(3-octylthiophene)/Fe2O3 nanoparticle composite, a time-resolved FTIR study

Photoinduced vibrational bands of poly(3-octylthiophene), P3OT, have been studied at room temperature by using time-resolved FTIR spectroscopy (TR-FTIRS) in the nanosecond to microsecond time domain. A photo-bleach occurs in the deformation band of CSC at 1463–1419 cm−1, and a few transient absorption bands occur at lower frequency (e.g. ∼1290 cm−1). The transient absorption band at 1290 cm−1 shows a signal exponential formation occurring in <200 ns, and a double exponential decay process, with lifetimes of 53 and 788 μs. Adding Fe2O3 nanoparticle into the polymer composite significantly enhances the photoinduced signal, indicating the interaction between polymer and nanoparticle. The dynamics of these photoinduced species on the nanosecond to microsecond time scale are discussed.