P3HT:PCBM bulk heterojunction solar cells were fabricated in two different configurations and were compared. A solar cell in matrix configuration showed lower R(s),R(sh), and V(oc) than an isolated cell due to the increased number of parasitic paths through neighboring devices. Solar cells in the matrix configuration were simulated using discrete cell parameters and the J(sc) obtained was corroborated with experimental value. The PEDOT:PSS layer enhances the effect of lateral charge transport and results in cross-talk-like behavior between arrays of solar cells with a common anode. These lead to significant errors, as high as 72.1%, in the calculated power conversion efficiencies. (C) 2008 Elsevier B.V. All rights reserved.