Central Core Substitutions and Film-Formation Process Optimization Enable Approaching 19% Efficiency All-Polymer...

Area of Science:

• Materials Science
• Organic Electronics
• Photovoltaics

Background:

• Molecular interactions and film formation critically influence all-polymer solar cell (all-PSC) performance.
• The central core structure of polymer acceptors significantly impacts blend film morphology and device efficiency.

Purpose of the Study:

• To investigate the effect of central core substitutions in quinoxaline (Qx)-fused polymer acceptors on all-PSC performance.
• To correlate molecular aggregation, intermolecular interactions, and film morphology with device efficiency.

Main Methods:

• Synthesis of three Qx-fused-core polymer acceptors (PQx1, PQx2, PQx3) with varied central core substitutions.
• Systematic regulation of molecular aggregation and intermolecular interactions.
• Fabrication and characterization of all-polymer solar cell devices using these acceptors.

Main Results:

• PQx3 demonstrated favorable aggregation and moderate interaction with PM6, achieving a power conversion efficiency (PCE) of 17.60% in binary devices.
• Optimized devices reached a PCE of 18.06%.
• Ternary devices incorporating PYF-T-o achieved a PCE of 18.82%.
• PM6:PQx3 devices showed high film-thickness tolerance, superior stability, and potential for large-scale applications (16.23% PCE in 1 cm²).

Conclusions:

• Central core structure optimization of polymer acceptors is crucial for efficient all-PSCs.
• Controlling film-formation processes is key to achieving high performance and stability.
• The developed PQx3 material shows significant promise for next-generation all-PSC technologies.