All-Polymer Solar Cells with 17% Efficiency Enabled by the "End-Capped" Ternary Strategy

Area of Science:

• Materials Science
• Renewable Energy
• Polymer Chemistry

Background:

• All-polymer solar cells (all-PSCs) show promise but lag in power conversion efficiency (PCE) compared to other organic solar cells.
• Excessive phase separation and poor miscibility between polymer donors and acceptors limit all-PSC performance.

Purpose of the Study:

• To introduce an "end-capped" ternary strategy to enhance the performance of all-polymer solar cells.
• To address the phase separation and miscibility issues in all-PSCs.

Main Methods:

• Fabrication of ternary devices using PM6:PM6TPO:PY-IT.
• Introduction of PM6TPO as a third component to modify morphology and miscibility.
• Characterization of device performance, light absorption, and morphology.

Main Results:

• Achieved a power conversion efficiency (PCE) of 17.0% in ternary devices.
• Observed enhanced light absorption and optimized morphology due to PM6TPO addition.
• Demonstrated reduced phase separation, improved stability, and thickness tolerance.

Conclusions:

• The "end-capped" ternary strategy is an effective method for improving all-PSC performance.
• This strategy offers a facile route to high-efficiency all-PSCs without complex synthesis.
• The developed ternary devices show potential for scalable applications with 1 cm² unit cells.