Ternary Strategy Enables 18.16% Efficiency in All-Small-Molecule Organic Solar Cells with Improved Fill Factor and...

Area of Science:

• Materials Science
• Organic Electronics
• Photovoltaics

Background:

• All-small-molecule organic solar cells (ASM-OSCs) performance is limited by poor phase separation due to donor/acceptor crystallization.
• This suboptimal morphology hinders exciton dissociation and charge generation.

Purpose of the Study:

• To enhance ASM-OSC performance by introducing L8-BO-F as a third component into the MPhS-C2:N3 binary system.
• To investigate the effects of this ternary strategy on active layer morphology, charge dynamics, and device efficiency.

Main Methods:

• Fabrication of ternary blend films incorporating MPhS-C2, N3, and L8-BO-F.
• Characterization of film morphology, molecular stacking, and crystallinity.
• Device performance testing to evaluate efficiency, open-circuit voltage, and fill factor.

Main Results:

• The ternary blend film exhibited improved molecular stacking, higher crystallinity, and optimized phase-separated morphology.
• Enhanced exciton dissociation, charge extraction, and reduced charge recombination were observed.
• The MPhS-C2:N3:L8-BO-F ternary device achieved a champion power conversion efficiency of 18.16%.

Conclusions:

• The ternary strategy effectively optimizes the active layer morphology in ASM-OSCs.
• L8-BO-F addition reduces voltage loss and enhances overall device performance.
• This approach offers a promising pathway for developing high-performance, low-energy-loss ASM-OSCs.