Intensity dependent but temperature independent charge carrier generation in organic photodiodes and solar cells

Measurements of the transient photoresponse of organic photodiodes and solar cells show a strong saturation effect in the quantum efficiency at laser fluences above approximately 3.3 mu J/cm(2). By a comparison of the measured intensity, temperature and field dependence of the transient pulse responses with extended drift-diffusion simulations, the loss of charge carriers can be traced back to a quadratic loss channel in the charge carrier generation process. In contrast to the predictions of the commonly used Onsager-Braun charge carrier generation model, we demonstrate that the dissociation of bound electron-hole-pairs is temperature independent but slightly field dependent. (C) 2013 Elsevier B.V. All rights reserved.