SINGLET AND TRIPLET EXCITED-STATE BEHAVIORS OF C-60 IN NONREACTIVE AND REACTIVE POLYMER-FILMS

The excited state behavior of C-60 has been investigated in polystyren e (PS) and poly(9-vinylcarbazole) (PVCz) polymer films. Picosecond and nanosecond laser flash photolysis techniques are employed to probe th e transient absorption properties of singlet and triplet excited state s in nonreactive (PS) and reactive (PVCz) microenvironments. In PS fil m, the absorption properties and lifetimes of these excited states are very similar to those observed in solutions. Encapsulation of C-60 Wi th PS results in the suppression of excited state self-quenching proce sses. Excited state charge transfer complex formation dominates in PVC z film. The absence of long-lived electron transfer products indicates that the charge separation in PVCz film is short-lived.