Biorenewable Solvents for High-Performance Organic Solar Cells

With the advent of nonfullerene acceptors (NFAs), organicphotovoltaic(OPV) devices are now achieving high enough power conversion efficiencies(PCEs) for commercialization. However, these high performances relyon active layers processed from petroleum-based and toxic solvents,which are undesirable for mass manufacturing. Here, we demonstratethe use of biorenewable 2-methyltetrahydrofuran (2MeTHF) and cyclopentylmethyl ether (CPME) solvents to process donor: NFA-based OPVs withno additional additives in the active layer. Furthermore, to reducethe overall carbon footprint of the manufacturing cycle of the OPVs,we use polymeric donors that require a few synthetic steps for theirsynthesis, namely, PTQ10 and FO6-T, which are blended with the Y-seriesNFA Y12. High performance was achieved using 2MeTHF as the processingsolvent, reaching PCEs of 14.5% and 11.4% for PTQ10:Y12 and FO6-T:Y12blends, respectively. This work demonstrates the potential of usingbiorenewable solvents without additives for the processing of OPVactive layers, opening the door to large-scale and green manufacturingof organic solar cells.