Low bandgap polymers for photon harvesting in bulk heterojunction solar cells

Encouraging progress has been made over the last few years in the field of photovoltaic solar cells using organic materials. Among the different concepts which have been proposed, the bulk heterojunction approach (formed by blending donor type conjugated polymers and acceptors like fullerenes) is attractive and significant progress in improving the power conversion efficiency of these devices was obtained recently. One of the possible improvements of this type of solar cells is the implementation of new materials absorbing the red and near infrared part of the solar spectrum, where the maximal photon flux of the sun is located. In this article, we will describe this strategy of photon harvesting in organic…