Pyrene-Based Dopant-Free Hole-Transport Polymers with Fluorine-Induced Favorable Molecular Stacking Enable Efficient...

Area of Science:

• Materials Science
• Organic Electronics
• Photovoltaics

Background:

• Perovskite solar cells (PSCs) require efficient hole-transport materials (HTMs) for optimal performance.
• Developing dopant-free HTMs is crucial for simplifying fabrication and enhancing device stability.
• Existing HTMs often face limitations in charge transport and interfacial interactions.

Purpose of the Study:

• To synthesize and characterize a novel class of polymeric HTMs.
• To investigate the impact of molecular design, including fluoro-substituted pyrene and selenophene units, on HTM properties.
• To evaluate the performance of these new HTMs in dopant-free PSCs.

Main Methods:

• Synthesis of novel polymeric materials incorporating fluoro-substituted pyrene, thiophene, and selenophene.
• Characterization of material properties, including π-π stacking and electronic structure.
• Fabrication and testing of perovskite solar cells using the developed HTMs.
• Performance evaluation through efficiency measurements and device longevity studies.

Main Results:

• The new polymeric HTMs exhibit enhanced π-π stacking and strong interaction with perovskite surfaces due to pyrene and selenium components.
• Fluorine substitution promotes a favorable face-on orientation of HTMs, facilitating efficient charge transport.
• Perovskite solar cells utilizing the PE10 HTM achieved a high power conversion efficiency of 22.3%.
• Devices demonstrated significantly enhanced operational stability and longevity.

Conclusions:

• The novel polymeric HTMs, particularly PE10, represent a significant advancement for dopant-free PSCs.
• The molecular design strategies employed effectively enhance charge transport and interfacial properties.
• These findings position the developed materials among the best-performing dopant-free HTMs for high-efficiency and stable perovskite solar cells.