Conjugated Polyelectrolyte with Long-Range Ordering and Compact Molecular Packing as Hole-Transporting Material for...

Area of Science:

• Materials Science
• Organic Electronics
• Photovoltaics

Background:

• Developing efficient and flexible organic solar cells (OSCs) requires advanced hole-transporting layer (HTL) materials.
• Conjugated polyelectrolytes (CPEs) offer tunable properties and solution processability but typically exhibit poor charge transport.

Purpose of the Study:

• To design and synthesize novel pH-neutral CPEs with enhanced crystallinity and molecular ordering for improved HTL performance.
• To investigate the structure-property relationships of tailored CPEs for OSC applications.

Main Methods:

• Synthesis of a series of pH-neutral CPEs with trifluoromethyl substituents on a triphenylamine unit.
• Characterization of film morphology, molecular ordering, and charge transport properties.
• Fabrication and performance testing of organic solar cells (OSCs) using the developed CPEs as HTLs.

Main Results:

• The TMPT-F CPE exhibited exceptional long-range molecular ordering and laminar packing, achieving a conductivity of 3.3 × 10^-2 S m^-1.
• OSCs utilizing the TMPT-F:PMA HTL demonstrated a power conversion efficiency (PCE) of 19.24%, surpassing PEDOT:PSS devices.
• Flexible OSCs with the TMPT-F:PMA HTL achieved a PCE of 16.52% and maintained 83% of their initial performance after 500 bending cycles.

Conclusions:

• The designed CPEs significantly enhance charge transport and film morphology for HTL applications in OSCs.
• The TMPT-F:PMA HTL offers superior performance and stability for both rigid and flexible organic solar cells.
• These findings pave the way for highly efficient and durable flexible organic electronics.