Role of a phthalocyanine–fullerene dyad in multilayered organic solar cells

A double-bridged phthalocyanine–fullerene dyad (H2Pc–C60ee) was used as photo-active intramolecular donor–acceptor system in a layered organic solar cell. In this device, a poly(3-hexylthiophene) (PHT) film was used as electron donor, whereas either C60 or perylene tetracarboxylic diimide (PTCDI) film was selected as electron acceptor. The introduction of the dyad layer leads to an enhancement of the power conversion efficiency (ηη) in all the examples, mainly due to an increase of the open-circuit voltage. By introducing the dyad in PTCDI-containing cells, the efficiency (being 0.32%) was enhanced by almost three times compared to that of the reference (0.12%). In C60-containing cells, the efficiency of the dyad sample (being 0.30%) was over one and half times higher than that of the reference in the absence of the dyad (0.18%). The role of such a dyad in the solar cells is discussed in detail.