Investigation of photoexcitations of conjugated polymer/fullerene composites embedded in conventional polymers

A promising approach to improve the processability of semiconducting polymers is their incorporation into host matrices formed by conventional polymers such as polyethylene (PE) or polystyrene (PS). We have characterized the linear optical properties of several guest–host systems by absorption and luminescence measurements and probed the excited states by photoinduced absorption measurements (PIA) and light induced electron spin resonance (LESR). The interesting photophysics of conjugated polymer/fullerene donor–acceptor system, showing an ultrafast photoinduced electron transfer and a metastable charge separation in the pristine state, has been investigated in such composites where the photoactive components are further embedded into a conventional polymer matrix. The composition of the blend and the relative concentration of the components are found to strongly influence the photoinduced interaction between the conjugated polymer and the fullerenes (