Ultrafast charge generation in a semiconducting polymer studied with THz emission spectroscopy
Schins, Juleon M.
Siebbeles, L. D. A.
University of Exeter (at the time of publication Euan Hendry was affiliated to Leiden University); Leiden University; Delft University of Technology; FOM Institute for Atomic and Molecular Physics, Amsterdam
Physical Review B
American Physical Society
We study the ultrafast charge generation in a semiconducting polymer (MEH-PPV) by measuring the radiated THz field after photoexciting the biased polymer with a femtosecond visible pulse. The subpicosecond temporal characteristics of the emitted wave reflects the ultrafast photoconductivity dynamics and sets an upper limit for charge generation of 200 fs following photoexcitation, and reveals the dispersive nature of charge transport in MEH-PPV. A comparison of the fields radiated from MEH-PPV and the well-characterized model semiconductor system (GaAs) allows for an accurate estimate of the quantum efficiency for charge generation in the polymer, found to be less than 1% . Both observations are consistent with ultrafast charge generation in semiconducting polymers through hot exciton dissociation.
Euan Hendry, Mattijs Koeberg, Juleon M. Schins, L. D. A. Siebbeles, and Mischa Bonn, Physical Review B, Vol. 70, article 033202 (2004). "Copyright © 2004 by the American Physical Society."
70 (3), article 033202