Ternary organic solar cells: using molecular donor or acceptor third components to increase open circuit voltage

Abstract

This report demonstrates that the open circuit voltage (V_OC) and power conversion efficiency (PCE) of polymer:fullerene (PBDB-T:PC₆₀BM) organic solar cells can be simultaneously enhanced by introducing a molecular π-conjugated donor or acceptor as a third component, thus affording high performance ternary blend devices. The use of a PDI-based acceptor “tPDI₂N-hex” or benzothioxanthene-based donor “tBTI-IDT” as a third component leads to V_OC increases of 60 to 150 mV without significant loss in power conversion efficiency (PCE). The best solar cell PCE of 8.8% was achieved by doping the PBDB-T:PC₆₀BM system with 10% by weight of tPDI₂N-hex.