Effects of end-capped acceptors subject to subtle structural changes on solution-processable small molecules for...

Area of Science:

• Materials Science
• Organic Electronics
• Photovoltaics

Background:

• Self-assembly is critical for organic solar cells (OSCs) and is highly sensitive to molecular structure.
• Optimizing molecular design is key to enhancing OSC performance and stability.

Purpose of the Study:

• To investigate the impact of subtle structural modifications in end-capped acceptors on the photovoltaic properties of organic solar cells.
• To establish structure-property relationships for designing efficient, solution-processable organic solar cells.

Main Methods:

• Synthesis of three novel end-capped acceptors with varying electron-withdrawing abilities.
• Incorporation of these acceptors into a benzodithiophene-based conjugated backbone.
• Characterization of optical, thermal, morphological, and electrical properties.
• Fabrication and testing of organic solar cell devices.

Main Results:

• Significant variations in molecular packing and hole mobilities were observed among the synthesized materials.
• Power conversion efficiencies (PCEs) increased from 3.0% to 6.4% for optimized devices.
• Fill factors ranged from 52% to 72%, correlating with molecular packing and electron-withdrawing effects.

Conclusions:

• End-capped acceptor structure critically influences molecular packing and photovoltaic performance in organic solar cells.
• The study provides valuable insights for developing high-efficiency, solution-processable organic solar cells through molecular engineering.