Achieving a Record Fill Factor of Approaching 84% and 21% Efficiency in Binary Organic Solar Cells via Solid Additive...

Area of Science:

• Materials Science
• Organic Electronics
• Photovoltaics

Background:

• Controlling morphology in organic solar cells (OSCs) using solid additives is key to device performance.
• The precise influence of intermolecular interactions between additives and photoactive materials on OSC morphology and efficiency requires further understanding.

Purpose of the Study:

• To investigate how tuning intermolecular interactions via molecular isomerization engineering impacts OSC morphology and performance.
• To explore the role of halogen-substituted additives in enhancing J-type stacking and absorption spectra of photoactive materials.

Main Methods:

• Utilized three isomers of iodine-substituted 1,2,4-trichlorobenzene as solid additives.
• Employed molecular isomerization engineering to precisely tune intermolecular interactions.
• Fabricated and characterized binary organic solar cells.

Main Results:

• Altering iodine substituent position improved additive miscibility and intermolecular interactions, forming a bicontinuous interpenetrating network.
• Achieved a high fill factor of ~84% and power conversion efficiency of nearly 21% (certified 20.42%).
• Demonstrated excellent storage stability with extrapolated T80 exceeding 10,000 hours.

Conclusions:

• Molecular isomerization engineering is an effective strategy for optimizing solid additive interactions in OSCs.
• The developed OSCs exhibit top-tier performance and remarkable operational stability.
• This work provides insights into structure-property relationships for solid additives in organic electronics.