Molecular Engineering on Bis(benzothiophene-S,S-dioxide)-Based Large-Band Gap Polymers for Interfacial Modifications...

Area of Science:

• Materials Science
• Organic Electronics
• Photovoltaics

Background:

• Developing universal interfacial materials is key for high-performance polymer solar cells (PSCs).
• Existing cathode interlayers often lack versatility for both conventional and inverted PSC architectures.
• Effective interlayers are crucial for efficient charge transport and minimizing energy losses.

Purpose of the Study:

• To synthesize novel alcohol-soluble conjugated polymers for use as universal cathode interlayers in PSCs.
• To evaluate the suitability of these polymers for both conventional and inverted PSC configurations.
• To enhance photovoltaic performance and device engineering through optimized interfacial layers.

Main Methods:

• Synthesis of two novel conjugated polymers, PBSON-P and PBSON-FEO, featuring a bis(benzothiophene-S,S-dioxide)-fused aromatics (FBTO) core and amino functional groups.
• Utilizing these polymers as cathode interfacial layers in both conventional and inverted PSC devices.
• Characterization of polymer properties including electron affinity, band gap, and energy levels.

Main Results:

• PBSON-P and PBSON-FEO demonstrated versatile electron-transporting abilities due to the FBTO unit's properties.
• The polymers possess wide band gaps suitable for light absorption in inverted PSCs, outperforming small band gap materials.
• Deep highest occupied molecular orbital energy levels effectively blocked holes, increasing the fill factor.

Conclusions:

• The synthesized polymers, PBSON-P and PBSON-FEO, function as effective amphibious cathode interfacial materials.
• These interlayers enable high photovoltaic performance in both conventional and inverted PSCs.
• The novel polymers offer a promising solution for advanced PSC device engineering.