Regulating Phase Separation Kinetics for High-Efficiency and Mechanically Robust All-Polymer Solar Cells.

Area of Science:

• Materials Science
• Organic Electronics
• Photovoltaics

Background:

• All-polymer solar cells (all-PSCs) offer superior stability and flexibility for wearable electronics.
• Current all-PSC power conversion efficiencies (PCEs) are limited by material properties and blend morphology.
• Existing PCEs lag behind small-molecule-acceptor-based organic solar cells.

Purpose of the Study:

• To enhance the PCE of all-polymer solar cells through molecular design and ternary blending.
• To optimize blend morphology and reduce voltage losses in all-PSCs.
• To develop stable, high-performance all-PSCs for large-scale flexible applications.

Main Methods:

• Synthesis and application of a novel terpolymer donor (PBDB-TFCl).
• Implementation of a ternary strategy with a guest donor (D18-Cl) and acceptor (PY-IT).
• Characterization of material properties, blend morphology, and photovoltaic device performance.

Main Results:

• The novel terpolymer PBDB-TFCl, in a ternary blend, achieved a record PCE of 18.6% (certified 18.3%).
• The ternary strategy optimized energy levels, reduced voltage losses, and improved film crystallinity.
• Large-area (36 cm²) flexible modules demonstrated a PCE of 15.1% with enhanced photostability and mechanical robustness.

Conclusions:

• Molecular design and ternary blending are effective strategies for improving all-PSC performance.
• The developed all-PSC system shows significant potential for stable, large-scale flexible solar energy harvesting.
• This work addresses key limitations in all-PSC efficiency and morphology for practical applications.