• effective medium model;
  • mobility;
  • organic solar cell;
  • P3HT:PCBM;
  • surface recombination velocity

The effect of charge carrier mobility and surface recombination velocity has been extensively investigated for poly(3-hexylthiophene) (P3HT): phenyl-C61-butyric acid methyl ester (PCBM) organic solar cells. We used the effective medium model and the solar cell simulator (SCAPS) to model the current–voltage (JV) characteristic and explore the charge carrier transport in P3HT:PCBM devices. We varied the charge carrier mobility for electrons and holes and surface recombination velocity at the contacts for majority and minority charge carriers, and calculated the solar cell characteristics: efficiency (η), open-circuit-voltage (Voc), short-circuit current (Jsc) and fill factor (FF). The significances of surface recombination velocity together with charge carriers mobility are calculated and discussed. We found that in general reduced surface recombination velocities at both contacts are very detrimental for organic solar cell performance especially for devices with low charge mobilities.