A 4-Arm Small Molecule Acceptor with High Photovoltaic Performance

Area of Science:

• Materials Science
• Organic Electronics
• Photovoltaics

Background:

• Small molecule acceptors (SMAs) are crucial for organic solar cell (OSC) efficiency.
• Current SMA designs commonly feature 2-arm structures with linear or curved backbones.

Purpose of the Study:

• To report a novel 4-arm SMA, 4A-DFIC, with a unique backbone structure.
• To investigate the properties and performance of 4A-DFIC in OSCs.

Main Methods:

• Synthesis of 4A-DFIC via reaction of an electron-rich aromatic diamine and hexaketocyclohexane.
• Characterization using single-crystal X-ray diffraction.
• Fabrication and testing of binary and ternary OSCs.

Main Results:

• 4A-DFIC possesses a rigid, twisted molecular plane and effective solid-state stacking.
• Exhibits a low band gap (1.40 eV) and broad light absorption (visible to near-infrared).
• Achieved power conversion efficiencies (PCEs) of 15.76% (binary) and 18.60% (ternary, certified 18.1%).

Conclusions:

• The 4-arm SMA architecture significantly enhances OSC performance.
• 4A-DFIC represents a new class of high-performance SMAs for next-generation solar cells.
• This work sets a new benchmark for multi-arm SMA-based OSCs.