A blend of a 5-ring n-octyloxy-substituted oligo(p-phenylene vinylene) and
C-60, sandwiched between two electrodes, has been used as the active layer
for an organic solar cell. It delivered external quantum efficiencies up to
60% in the visible and 70% in the UV part of the spectrum. To unambiguousl
y determine which parts of the bulk heterojunction structure are responsibl
e for the rectifying behaviour and which can be considered as ohmic, the I-
V characteristics of several other devices were investigated. It is found t
hat the presence of C-60 in a bulk heterojunction solar cell introduces fil
l factor reducing shunting paths. (C) 2000 Elsevier Science B.V. All rights
reserved.