High-Efficiency Organic Solar Cells Enabled by Siloxane-Functionalized Pyrazine Terpolymers: Synergizing Performance,...

Area of Science:

• Materials Science
• Organic Electronics
• Photovoltaics

Background:

• Scalable and sustainable organic solar cells (OSCs) face challenges in balancing high performance, morphological control, and non-halogenated solvent processing.
• Achieving high power conversion efficiency (PCE) requires optimized morphology and molecular ordering.

Purpose of the Study:

• To address the bottleneck in OSC processing by designing novel terpolymers.
• To enhance morphological controllability and compatibility with non-halogenated solvents for scalable OSC fabrication.

Main Methods:

• Rational terpolymer design by integrating a siloxane-functionalized electron-deficient pyrazine unit (DTCPz-SiO) into the D18 backbone.
• Synthesis and characterization of the optimized terpolymer DN1 containing 5 mol% DTCPz-SiO.
• Fabrication and performance evaluation of binary and ternary organic solar cells.

Main Results:

• The DTCPz-SiO unit enhanced backbone planarity, π-π stacking, and crystallization through intramolecular interactions.
• DN1 terpolymers demonstrated improved donor-acceptor miscibility and compatibility with non-halogenated solvents.
• DN1-based binary OSCs achieved a PCE of 20.1% (vs. 18.7% for parent polymer), with efficiencies around 19.5% using non-halogenated solvents.
• Ternary OSCs reached outstanding PCEs of 20.9% (chlorinated) and 20.0% (non-halogenated).

Conclusions:

• Siloxane-functionalized terpolymers offer an effective strategy for regulating multi-scale morphology and processing tolerance in OSCs.
• This molecular design approach provides insights for developing scalable and sustainable organic solar cell systems.
• The developed terpolymers enable high-efficiency OSCs compatible with environmentally friendly processing methods.