Figure 1.
(a) Current density–voltage characteristics of solar cells comprising a PM6 donor and PC61BM, IT-4F, or Y6 as the acceptor. The symbols represent experimental characteristics, the solid lines are fits of the data by drift diffusion simulations, with the experimental charge-carrier mobilities as input. With the mobilities known, the recombination rate determines the fill factor, where the results for Langevin recombination (γ = 1) are represented by the dash-dotted lines. (b) Langevin prefactors directly obtained by Eq. (2) from the measured electron, hole, and double-carrier currents in dark.
