Low-Bandgap Non-fullerene Acceptors Enabling High-Performance Organic Solar Cells

Great progress in organic solar cells (OSCs) has been recently achieved owing to the advent of non-fullerene acceptors (NFAs). Indeed, low-bandgap NFAs ranging from 1.3 to 1.6 eV with broad absorption and easily tunable energy levels can utilize more solar radiation and maintain a small voltage loss when paired with suitable donors. Efficient OSCs are dependent on the good compatibility between donor and acceptor materials, active layer morphology control, and device engineering. In this review, we summarize some design and synthesis strategies for NFAs, achieving low bandgap and high power conversion efficiency. We also propose solutions toward innovative materials and device engineering to advance the development and applications of OSCs.