Randomly Distributed Conjugated Polymer Repeat Units for High-Efficiency Photovoltaic Materials with Enhanced...

Area of Science:

• Materials Science
• Organic Electronics
• Polymer Chemistry

Background:

• PffBT4T-2OD is a benchmark polymer for organic solar cells.
• Structurally disordered polymers can offer processing advantages.
• Controlling polymer aggregation is crucial for device performance.

Purpose of the Study:

• To develop terpolymer derivatives of PffBT4T-2OD with improved solubility and processability.
• To investigate the impact of structural modifications on aggregation and optoelectronic properties.
• To evaluate the performance of solar cells fabricated from these new terpolymers.

Main Methods:

• Synthesis of three terpolymer derivatives by varying bithiophene linker content.
• Characterization of aggregation behavior in solution.
• Fabrication and testing of organic solar cells using PC71BM as the acceptor.
• Device performance analysis including power conversion efficiency and fill factor.

Main Results:

• Terpolymers showed reduced aggregation with increased thiophene content.
• Redox and optoelectronic properties remained comparable to PffBT4T-2OD.
• Solar cells achieved over 9.5% power conversion efficiency with high fill factors (>70%).
• Devices processed on room-temperature substrates maintained high performance with thick active layers (~400 nm).

Conclusions:

• The random terpolymer approach successfully enhances solubility and processability.
• Device performance is maintained despite improved processing conditions.
• These terpolymers represent a promising advancement for practical organic solar cell applications.