The performance of organic photovoltaic cells consisting of tin-phthalocyanine (SnPc) as a donor layer and fullerene (C-70) as an acceptor layer was improved by constructing a multilayer device incorporating two heterojunctions with a thin intervening layer of Au or Ag as an internal electrode. The photovoltaic conversion efficiency of the ITO/PEDOT: PSS/SnPC/C-70/Ag/SnPc/C-70/Ag cell was 1.33%, with an open-circuit photovoltage of ca. 0.90 V. These values were approximately twice as large as those for the corresponding single-heterojunction cell. (c) 2006 Published by Elsevier B.V.