Ion implantation effect on vapor deposited organic solar cells based on pn junctions or interpenetrating networks of donor and acceptor small molecules

In this paper we report the achievement, with a co-evaporation set up, of photovoltaic cells based on single heterojunction or interpenetrating networks of organic donor and acceptor molecules as active layer. A donor-acceptor couple zinc phthalocyanine-C₆₀ (ZnPc-C₆₀) has been studied, sandwiched between indium tin oxide (ITO) and aluminum contacts. In the case of heterojunctions, sodium ion implantation of the C₆₀ layer or iodine ion implantation of the phthalocyanine layer improves the current-voltage I(V) characteristics of the single heterojunctions. An increase of both short circuit current Ice and open circuit voltage Voc has been noticed.