Surpassing the 10% efficiency milestone for 1-cm² all-polymer solar cells

Area of Science:

• Materials Science
• Organic Electronics
• Photovoltaics

Background:

• Naphthalenediimide-based polymers are key for high-performance all-polymer solar cells (all-PSCs).
• Thinner active layers reduce charge recombination but limit near-infrared light absorption.
• Thicker layers enhance light harvesting but exacerbate charge recombination.

Purpose of the Study:

• To optimize light propagation and morphology in all-PSCs for improved efficiency.
• To overcome the trade-off between light harvesting and charge recombination in thick active layers.

Main Methods:

• Fabrication of thick bulk-heterojunction films (~350 nm) for enhanced photo-harvesting.
• Utilizing a non-halogenic additive to induce a well-ordered microstructure.
• Morphology optimization to suppress charge recombination loss.

Main Results:

• Effective light management achieved in thick active layers for near-infrared absorption.
• Suppression of recombination loss through microstructural control.
• Achieved over 10% power conversion efficiency in thick-film all-PSCs with a 1 cm² active area.

Conclusions:

• Combined light management and morphology control are crucial for high-performance thick-film all-PSCs.
• Non-halogenic additives can engineer beneficial microstructures.
• Demonstrated potential for large-scale production and application of all-PSCs.