Meta-Analysis of Molecular Design Strategies for Non-Fullerene Acceptor Based Organic Solar Cell Materials

The design of high-performing OSC materials is an active field of research. Many review articles summarize certain subclasses of NFAs, however, no broad overall analysis has been performed on the photovoltaic impact of chemical modifications made. This meta-analysis investigates various molecular design strategies for NFAs and donors and their effects on OSC device performance. Using a new dataset containing 1975 NFA/donor pairs, we performed matched-pair analysis on many design strategies to try to discern whether it has a significant impact on PCE. For the NFA, the class and size of the NFA, heteroatom substitution, types of rings and their sequence in the fused core, side chains, halogenation of terminal groups, and the presence of a pi-bridge are examined. For the donor polymers, the monomer identities, the types of side chains, and the halogenation of the polymer are examined. Some molecular design strategies that were found to significantly improve the PCE include branched instead of linear side chains, fused cores containing 8 rings, fused NFAs containing pyran, pyrrole, and selenophene, fused cores containing an odd number of thiophenes, the presence of pi-bridge units, halogenating the NFA and donor, incorporation of alkylsilyl chains instead of alkyl chains in donor polymers, as well as multiple others.