Porphyrin Acceptors Improve the Crystallization of Y6 and the Exciton Dissociation in Ternary Organic Solar Cells

The development of the third component is very important for ternary organic solar cells (OSCs). Herein, we synthesized two porphyrin electron acceptors (Zn-Por-IC4F and Zn-Por-IC) with an A-2π-D-2π-A (A: electron acceptor unit, D: electron donor unit) structure as the third component for PTB7-Th:Y6 devices. Zn-Por-IC4F and Zn-Por-IC in the ternary OSCs can improve the crystallization of Y6 and the exciton dissociation, therefore enhancing their fill factors (FF). As a result, the power conversion efficiencies (PCEs) of the PTB7-Th:Y6:Zn-Por-IC4F and PTB7-Th:Y6:Zn-Por-IC ternary OSCs are improved to 11.6 and 10.67%, which are increased by 21 and 11.5%, respectively, compared with that of PTB7-Th:Y6 binary devices with a PCE of 9.57%. This is the first report that porphyrins are employed as electron acceptors in ternary OSCs, though porphyrins have been widely used as donor materials of OSCs, which may open up an avenue for the applications of porphyrins in OSCs and provide guidelines for designing photovoltaic materials.