Low-Cost Nonfused-Ring Electron Acceptors Enabled by Noncovalent Conformational Locks.

Area of Science:

• Materials Science
• Organic Electronics
• Photovoltaics

Background:

• Fullerene derivatives dominated organic solar cells (OSCs) for two decades.
• Fused-ring electron acceptors (FREAs) advanced OSC efficiency but face complex synthesis and high costs.
• A need exists for novel nonfullerene acceptors (NFAs) that are cost-effective and highly efficient.

Purpose of the Study:

• To explore the development of nonfused-ring electron acceptors (NFREAs) utilizing the noncovalent conformational locks (NoCLs) strategy.
• To provide an overview of NFREAs, comparing them with FREAs and detailing structural simplification.
• To analyze molecular design principles and structure-property-performance relationships in NFREAs for optoelectronic applications.

Main Methods:

• Theoretical and experimental exploration of the NoCLs strategy.
• Development of a descriptor to quantify NoCL strength.
• Design and synthesis of NFREAs and polymerized NFREAs (PNFREAs).

Main Results:

• The NoCLs strategy enhances molecular rigidity and planarity, improving charge transport and reducing energy loss in organic semiconductors.
• NFREAs demonstrate simplified structures and synthesis routes compared to FREAs, while maintaining high coplanarity.
• Selected NFREAs exhibit remarkable photovoltaic performance, showcasing potential for cost-effective and efficient OSCs.

Conclusions:

• NFREAs, enabled by the NoCLs strategy, represent a promising pathway towards highly efficient and economically viable organic solar cells.
• The strategy allows for structural simplification without compromising optoelectronic performance.
• Further research into NFREAs, particularly PNFREAs, is crucial for balancing efficiency, stability, and cost in next-generation OSCs.