A simple fluorene core-based non-fullerene acceptor for high performance organic solar cells

Area of Science:

• Materials Science
• Organic Electronics
• Photovoltaics

Background:

• Organic solar cells (OSCs) offer a promising alternative to conventional photovoltaics due to their potential for low-cost manufacturing and flexibility.
• Non-fullerene acceptors (NFAs) are crucial components in high-performance OSCs, enabling tunable electronic properties and improved device stability.
• Developing efficient and cost-effective NFAs is essential for the commercial viability of organic solar cell technology.

Purpose of the Study:

• To design and synthesize a novel small molecule non-fullerene acceptor (NFA) based on a fluorene core.
• To investigate the structure-property relationships of the developed NFA for application in solution-processable bulk heterojunction (BHJ) organic solar cells (OSCs).
• To evaluate the photovoltaic performance of the new NFA and establish a benchmark efficiency for this class of materials.

Main Methods:

• A small molecule acceptor, designated FRd2, was synthesized using a simplified protocol.
• The FRd2 molecule features a fluorene core, furan π-spacers, and rhodanine end-capping groups.
• Fabrication and characterization of bulk heterojunction organic solar cells (OSCs) using the FRd2 acceptor.

Main Results:

• The synthesized FRd2 molecule exhibits extended π-conjugation due to the furan units and electron-withdrawing rhodanine groups.
• Solution-processable bulk heterojunction organic solar cells (OSCs) incorporating FRd2 achieved a power conversion efficiency (PCE) of 9.4%.
• This efficiency represents the highest reported PCE for organic solar cells utilizing this specific category of small molecule non-fullerene acceptors.

Conclusions:

• The developed FRd2 molecule is a highly efficient small molecule non-fullerene acceptor for organic solar cells.
• The simplified synthesis and high performance demonstrate the potential of this molecular design for cost-effective and efficient organic photovoltaic applications.
• FRd2 establishes a new benchmark for fluorene-based non-fullerene acceptors in solution-processed OSCs.