Abstract
We determine the efficiencies for the formation of excitons and charge carriers following ultrafast photoexcitation of a semiconducting polymer (MEH-PPV). The simultaneous, quantitative determination of exciton and charge photoyields is achieved through subpicosecond studies of both the real and the imaginary components of the complex conductivity over a wide frequency range. Predominantly excitons, with near-unity quantum efficiency, are generated on excitation, while only a very small fraction () of free charges are initially excited, consistent with rapid () hot exciton dissociation. These initial charges are very short lived, decaying on subpicosecond time scales.
- Received 8 August 2003
DOI:https://doi.org/10.1103/PhysRevLett.92.196601
©2004 American Physical Society