Facile Strategy for Reducing Cell-to-Module Efficiency Gap in Organic Solar Cells by Controlling the Preaggregation...

Area of Science:

• Materials Science
• Organic Electronics
• Renewable Energy

Background:

• Organic solar cells (OSCs) achieve high efficiencies in small unit cells (>20%).
• Scaling up OSCs to large areas presents challenges like increased resistance and morphology control.
• These challenges limit the power conversion efficiency (PCE) of large-area OSC modules.

Purpose of the Study:

• To develop efficient large-area organic solar cell (OSC) modules using a preaggregation control technique.
• To investigate the impact of D18 additive on film morphology and device performance.
• To reduce the efficiency gap between small-area cells and large-area modules.

Main Methods:

• Incorporation of a low-concentration D18 solution into a PM6:L8-BO donor-acceptor blend.
• Utilizing a preaggregation control technique to achieve optimal chain entanglement and morphology.
• Fabrication and characterization of OSC devices with varying areas (0.04 cm², 4.725 cm², 30.24 cm²).

Main Results:

• The D18 additive resulted in macroscopically clean films and microscopically phase-separated morphologies.
• PCEs for larger areas (4.725 cm² and 30.24 cm²) increased from 14.85% to 15.31% and 12.77% to 13.49%, respectively.
• The largest module (30.24 cm²) showed reduced load resistance and a decreased cell-to-module efficiency gap (26.3% to 24.3%).

Conclusions:

• The preaggregation control technique with D18 is effective in improving large-area OSC module performance.
• Optimized morphology and reduced resistance are key factors for enhanced efficiency in scaled-up devices.
• This method significantly narrows the efficiency gap, paving the way for practical large-area OSC applications.