The charge carrier drift mobility in disordered semiconductors is commonlygraphically extracted from time-of-flight (ToF) photocurrent transientsyielding a single transit time. However, the term transit time is ambiguouslydefined and fails to deliver a mobility in terms of a statistical average.Here, we introduce an advanced computational procedure to evaluate ToFtransients, which allows to extract the whole distribution of transit times andmobilities from the photocurrent transient, instead of a single value. Thismethod, extending the work of Scott et al. (Phys. Rev. B 46, 8603), isapplicable to disordered systems with a Gaussian density of states (DOS) andits accuracy is validated using one-dimensional Monte Carlo simulations. Wedemonstrate the superiority of this new approach by comparing it to the commongeometrical analysis of hole ToF transients measured on poly(3-hexylthiophene-2,5-diyl) (P3HT). The extracted distributions provide access to avery detailed and accurate analysis of the charge carrier transport. Forinstance, not only the mobility given by the mean transit time, but also themean mobility can be calculated. Whereas the latter determines the macroscopicphotocurrent, the former is relevant for an accurate determination of theenergetic disorder parameter $\sigma$ within the Gaussian disorder model (GDM).$\sigma$ derived by using the common geometrical method is, as we show,underestimated instead.
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