Abstract
Relaxation dynamics of even parity ( ) states in poly( -phenylene vinylene) derivatives are studied using a novel fsec transient spectroscopy, in which two different excitation pulses successively generate odd parity ( ) excitons at 2.2 eV and then reexcite them to higher states. For reexcitation energies ultrafast internal conversion back to takes place in accordance with Vavilov-Kasha's rule. However, for the decay occurs in a nonemissive state identified as a polaron pair, showing that the states above 3.3 eV mediate charge transfer.
- Received 8 October 1999
DOI:https://doi.org/10.1103/PhysRevLett.85.2196
©2000 American Physical Society