Activating π-Electron Conjugated Networks of Self-Assembled Multilayers for 21.1% Efficiency Organic Solar Cells

Area of Science:

• Organic electronics
• Materials science
• Supramolecular chemistry

Background:

• Self-assembled monolayers (SAMs) exhibit limited electrical conductivity due to thinness and disorder.
• Improving carrier transport and stability in organic electronic materials is crucial.

Purpose of the Study:

• To design a novel π-skeleton unit for self-assembled multilayers (SAMULs).
• To enhance electrical conductivity, carrier transport, and stability in organic electronics.
• To improve the efficiency of organic solar cells.

Main Methods:

• Synthesized a π-skeleton unit based on 3,6-dibenzothiophen-9H-carbazol.
• Constructed self-assembled multilayers (SAMULs) utilizing the new molecular design.
• Fabricated and characterized binary organic solar cells.

Main Results:

• The π-expanded skeleton promoted molecular crystallinity and face-on orientation.
• A large π-electron conjugated network was activated, enhancing charge delocalization.
• Achieved superior electrical conductance, hole-transporting capability, and photochemical stability.
• Attained a record 21.13% power conversion efficiency (certified 20.77%) with an 83.48% fill factor in organic solar cells.

Conclusions:

• The novel π-skeleton unit significantly improves SAMUL performance.
• This molecular design offers a new strategy for advancing organic electronics.
• The developed SAMULs demonstrate high potential for efficient organic solar cells.