Abstract
The electrodeless flash-photolysis time-resolved microwave conductivity technique () has been used to study the photogeneration of charge carriers in spin-coated films of regioregular poly(3-hexylthiophene) , over the photon energy range from 1.9 to for incident light intensities from to per pulse. The initial, single-photon quantum yield of photoionization, , has been estimated from the low-intensity limit to the photoconductivity based on a charge carrier mobility of (determined in separate pulse-radiolysis experiments on bulk ). The value of is constant at within the range , which encompasses the first electronic absorption band of . Above , increases, up to a value of at . The activation energy of the photoconductivity was found to be approximately at all photon energies. The high-intensity, sublinear dependence of the photoconductivity can be described by the occurrence of either exciton-exciton annihilation or diffusional charge recombination with rate coefficients of and .
1 More- Received 19 February 2004
DOI:https://doi.org/10.1103/PhysRevB.70.045203
©2004 American Physical Society