Asymmetric Π-Bridge Engineering Enables High-Permittivity Benzo[1,2-B:4,5-b']Difuran-Conjugated Polymer for Efficient...

Area of Science:

• Materials Science
• Organic Electronics
• Photovoltaics

Background:

• Organic solar cells (OSCs) rely on charge dynamics influenced by material dielectric constants.
• Developing novel conjugated copolymers is crucial for improving OSC performance.

Purpose of the Study:

• To design and synthesize novel conjugated copolymers based on benzo[1,2-b:4,5-b']difuran (BDF) and benzotriazole (BTz).
• To investigate the effect of π-bridge structure on dielectric constant and molecular packing.
• To optimize OSC performance using these novel materials.

Main Methods:

• Synthesis of BDF-BTz conjugated copolymers with varying π-bridges.
• Characterization of dielectric constant (ɛr), molecular packing, and miscibility.
• Fabrication and testing of OSC devices with non-fullerene acceptor Y6 and fullerene derivative PCBO-12.

Main Results:

• PBDF-TF-BTz exhibited a higher dielectric constant (4.22) compared to its counterparts.
• PBDF-TF-BTz showed improved molecular packing and miscibility, leading to efficient exciton dissociation and charge transport.
• OSCs based on PBDF-TF-BTz achieved a power conversion efficiency of 17.01% and 18.10% with ternary component addition.

Conclusions:

• The study highlights the importance of high-permittivity materials in OSCs.
• PBDF-TF-BTz is identified as a promising polymer donor for high-performance organic solar cells.
• This work offers an effective strategy for developing advanced photovoltaic materials.