Intrinsically Chemo- and Thermostable Electron Acceptors for Efficient Organic Solar Cells

The traditional preparation of non-fullerene acceptors (NFAs) via Knoevenagel condensation reaction (KCR) of aldehyde and active methylene leaves vulnerable and reversible exocyclic vinyl bonds in structures, which undermine the intrinsic chemo- and photostability of NFAs. In this work, we demonstrate a new access to acceptor-donor-acceptor (A-D-A) NFAs via Stille coupling between new electron deficient groups and classic donor core in over 90% yield, wherein the robust carbon-carbon bonds, replacing the exocyclic double bonds from traditional KCR, result in stable A-D-A acceptors, Q1-XF (X representing 0, 2 and 4 fluorine atoms, respectively). Among the three studied examples, Q1-4F exhibits improved optoelectronic and electron transport properties, leading to the best photovoltaic performance with optimal charge kinetics for Q1-4F based OSCs. Overall, this strategy can lead to a new way for developing stable photovoltaic materials.

Automated summary

In this study, a new method for synthesizing stable A-D-A type NFAs was demonstrated using Stille coupling, which shows improved optoelectronic and electron transport properties compared to traditional KCR methods. This approach has the potential to provide better performance for photovoltaic devices based on NFAs.