Hole-transporting interlayers based on pyrazine-containing conjugated polymers for perovskite solar cells

Area of Science:

• Materials Science
• Renewable Energy
• Organic Electronics

Background:

• Perovskite solar cells (PSCs) are a rapidly advancing photovoltaic technology.
• Hole-transport materials (HTMs) are critical for PSC efficiency and stability.
• Developing efficient, low-cost HTMs is essential for commercializing PSCs.

Purpose of the Study:

• To synthesize and evaluate novel conjugated polymers as dopant-free HTMs for n-i-p PSCs.
• To investigate the structure-property relationships of these polymers in PSC devices.
• To assess the power conversion efficiency (PCE) and operational stability of the developed HTMs.

Main Methods:

• Synthesis of two novel conjugated polymers incorporating benzo[1,2-b:4,5-b']dithiophene and thiophene-bridged pyrazine units.
• Fabrication of n-i-p PSC devices using the synthesized polymers as dopant-free HTMs.
• Characterization of PSC performance, including power conversion efficiency (PCE) and operational stability under continuous illumination.

Main Results:

• The polymer PBPyT-ex achieved a maximum PCE of 17.5%.
• The polymer PBPyT-in achieved a PCE of 14.9%.
• The superior performance of PBPyT-ex was attributed to improved HTM film quality.
• Operational stability exceeding 1500 hours under continuous illumination was observed.

Conclusions:

• The combination of pyrazine, thiophene, and benzodithiophene units is a successful strategy for designing polymeric HTMs.
• The developed dopant-free HTMs offer encouraging efficiency and high operational stability for PSCs.
• These findings contribute to the advancement of efficient and stable perovskite solar cell technology.