Dimer Acceptor Adopting a Flexible Linker for Efficient and Durable Organic Solar Cells

Area of Science:

• Materials Science
• Organic Electronics
• Photovoltaics

Background:

• Organic solar cells (OSCs) show promise but suffer from poor long-term stability, hindering commercialization.
• Developing novel photovoltaic materials is key to advancing OSC technology.

Purpose of the Study:

• To enhance the stability and efficiency of organic solar cells (OSCs).
• To address the challenge of active layer morphology degradation in OSCs.

Main Methods:

• A novel dimer acceptor (dT9TBO) with a flexible linker was synthesized.
• dT9TBO was incorporated into small-molecule acceptors to create a molecular alloy.
• The morphology, thermal stability, and mechanical durability of the resulting OSCs were evaluated.

Main Results:

• The PM6:Y6:dT9TBO-based OSC achieved a power conversion efficiency (PCE) of 18.41%.
• The devices exhibited excellent thermal stability, with negligible decay after 1800 hours at 65°C.
• Flexible OSCs maintained 95% of their initial PCE after 1500 bending cycles, demonstrating superior mechanical durability.

Conclusions:

• The developed dT9TBO material effectively stabilizes active layer morphology by enhancing intermolecular packing and suppressing diffusion.
• This approach offers a viable strategy to overcome the efficiency-stability trade-off in organic solar cells.
• The findings pave the way for more robust and commercially viable organic photovoltaic devices.