Fabricating High-Performance Organic Solar Cells by Using Inside-Chain Chlorinated Acceptor as a Ternary Component

Area of Science:

• Materials Science
• Organic Electronics
• Photovoltaics

Background:

• Small-molecule acceptors are crucial for organic solar cells (OSCs).
• Chlorination strategies can influence molecular packing and film morphology.
• Optimizing morphology is key to enhancing OSC performance.

Purpose of the Study:

• To investigate the impact of inside-chain chlorination on small-molecule acceptor morphology.
• To evaluate the performance of chlorinated acceptors in binary and ternary OSCs.
• To correlate molecular structure with device efficiency.

Main Methods:

• Design and synthesis of two molecules, WLA1 and WLA2, with varying chlorination.
• Fabrication and characterization of binary and ternary OSCs using WLA1 and WLA2.
• Analysis of film morphology, crystallinity, and molecular stacking.
• Performance testing of OSC devices to determine power conversion efficiency (PCE).

Main Results:

• Chlorinated WLA2 demonstrated enhanced crystallinity and molecular stacking compared to WLA1.
• WLA2-based binary OSCs achieved a PCE of 16.80%.
• WLA2 incorporation into a ternary system (D18:L8-BO) improved crystallinity, induced fiber phase morphology, and resulted in a PCE of 19.64%.

Conclusions:

• Inside-chain chlorination is an effective strategy for tuning small-molecule acceptor properties.
• Ternary blending with chlorinated acceptors significantly boosts OSC performance.
• The study highlights the potential of WLA2 for high-performance organic solar cell applications.