Progress in Non-Fullerene Acceptors: Evolution from Small to Giant Molecules.

Area of Science:

• Materials Science
• Organic Electronics
• Photovoltaics

Background:

• Organic solar cells (OSCs) are rapidly advancing, driven by the development of non-fullerene acceptors (NFAs).
• NFAs are categorized into small molecule acceptors (SMAs) and polymerized small molecule acceptors (PSMAs), each with distinct properties and performance metrics.
• SMAs offer high power conversion efficiency (PCE) near 20%, while PSMAs provide improved stability and flexibility, with PCEs exceeding 18%.

Purpose of the Study:

• To introduce the latest developments in SMAs, PSMAs, and the emerging class of giant molecule acceptors (GMAs).
• To analyze the advantages of GMAs, highlighting their unique molecular structure and performance characteristics.
• To provide perspectives on the opportunities and challenges associated with GMAs for future organic solar cell applications.

Main Methods:

• Review of recent scientific literature on non-fullerene acceptors in organic solar cells.
• Comparative analysis of performance metrics (PCE, stability, flexibility) for SMAs, PSMAs, and GMAs.
• Structure-property relationship investigation for giant molecule acceptors.

Main Results:

• Giant molecule acceptors (GMAs) have emerged as a novel class of materials combining advantages of SMAs and PSMAs.
• Devices based on GMAs have demonstrated power conversion efficiencies exceeding 19%.
• GMAs possess a well-defined molecular structure, addressing limitations of previous NFA categories.

Conclusions:

• GMAs represent a significant advancement in NFA technology for organic solar cells.
• Their unique structure offers a promising pathway to further enhance OSC performance and applicability.
• Further research into GMAs is crucial to overcome synthesis costs and batch repeatability challenges for commercial viability.