Optimization of Difluorophenazine-Based Polymers via Substituent Modifications for Solar Energy Applications

Area of Science:

• Materials Science
• Organic Electronics
• Polymer Chemistry

Background:

• Donor-acceptor conjugated polymers are crucial for organic electronics.
• Phenazine-based polymers offer tunable electronic properties.
• Substituent effects on polymer performance require further investigation.

Purpose of the Study:

• To synthesize and characterize novel donor-acceptor polymers.
• To investigate the influence of donor-side substituents on optoelectronic properties.
• To evaluate polymer performance in bulk heterojunction solar cells.

Main Methods:

• Design and synthesis of polymers with varying substituents (H, Cl, F, S) on benzodithiophene donors and Difluorophenazine acceptors.
• Measurement of optical band gaps and HOMO energy levels.
• Fabrication and testing of bulk heterojunction solar cells using Y6 as an acceptor.

Main Results:

• Systematic tuning of optical band gaps (1.72-1.82 eV) and HOMO levels (-5.42 to -5.58 eV) through substituent modification.
• Power conversion efficiencies (PCEs) ranged from 3.85% to 7.79%.
• The fluorinated polymer P(BDTTF-TffPzT) achieved the highest PCE (7.79%) with excellent Jsc (19.65 mA cm⁻²), Voc (0.825 V), and FF (0.481).

Conclusions:

• Donor-side substituent engineering is a viable strategy for optimizing phenazine-based polymer optoelectronic properties.
• Fluorine substitution enhances polymer performance in solar cell applications.
• These findings provide valuable insights for designing high-performance organic electronic materials.