The tendency to saturation in the collected charge as a function of light intensity in Langmuir-Blodgett films of poly(3-hexylthiophene) (PHT) has been studied. The tendency to saturation can have two reasons; that the space charge limited current regime has been reached, or influence of very fast bimolecular recombination. We have studied these two cases, and we conclude that bimolecular recombination is a probable cause for the tendency to saturation. The hole mobility in PHT can therefore possibly be estimated as high as 1 cm2/Vs in the initial stage after photoexcitation.
Juška, G., Arlauskas, K., Österbacka, R., Sandberg, H., & Stubb, H. (1999). Charge carrier mobility in Langmuir-Blodgett films of poly (3-hexylthiophene). Synthetic Metals, 101(1), 88-89. https://doi.org/10.1016/S0379-6779(98)01203-X