High-Performance G-Dimer Acceptor-Based Flexible Organic Solar Cells Optimized by Temperature-Dependent Film...

Area of Science:

• Materials Science
• Organic Electronics
• Photovoltaics

Background:

• Giant Dimer (G-Dimer) acceptors show potential in organic solar cells.
• Morphology optimization of donor-acceptor (D-A) blends is crucial for performance.
• Limited research exists on optimizing G-Dimer based D-A blend morphology.

Purpose of the Study:

• Investigate the impact of processing temperature on PM6:G-DimerC8C10 blend morphology.
• Understand how temperature affects donor aggregation, phase distribution, and device performance.
• Identify optimal processing conditions for high-efficiency flexible organic solar cells.

Main Methods:

• Fabrication of organic solar cells using PM6 donor and G-DimerC8C10 acceptor.
• Systematic variation of processing temperatures during blend preparation.
• Morphological characterization of the active layer, including aggregation and phase distribution.
• Performance evaluation of devices, including power conversion efficiency (PCE).

Main Results:

• Increased processing temperature enhanced donor (PM6) aggregation due to reduced nucleation sites and faster diffusion.
• Nanofiber formation with larger diameters was observed at higher temperatures.
• Vertical phase distribution shifted, with increased donor and decreased acceptor content from bottom to top.
• Optimized morphology led to improved exciton dissociation and hole transport rates.

Conclusions:

• Processing temperature is a critical factor for controlling morphology in PM6:G-DimerC8C10 blends.
• Optimized temperature (90°C) yielded superior D-A blend morphology and device performance.
• A record PCE of 14.38% was achieved for a 1 cm² flexible device fabricated via slot-die coating.
• The findings support the potential for upscaling G-Dimer based organic solar cell applications.