Polyfluoride Acceptor with Limited Molecular Diffusion Enables Efficient and Stable Ternary Organic Solar Cells

Area of Science:

• Materials Science
• Organic Electronics
• Photovoltaics

Background:

• Organic solar cells (OSCs) face stability challenges due to photovoltaic molecule diffusion under operational stress.
• Morphological instability in the active layer of OSCs compromises long-term performance.
• High glass transition temperature (Tg) materials can suppress molecular diffusion, balancing efficiency and stability.

Purpose of the Study:

• To synthesize a novel dimerized small-molecule acceptor (F6D) with an enhanced glass transition temperature (Tg).
• To improve the morphological stability and operational lifetime of organic solar cells.
• To achieve a balance between high power conversion efficiency and long-term stability in ternary OSCs.

Main Methods:

• Synthesis of a dimerized small-molecule acceptor (F6D) using a polyfluoride linker.
• Incorporation of F6D as a third component in a ternary organic solar cell blend (PM6:Y6:F6D).
• Characterization of the ternary device's thermal stability, morphology, and photovoltaic performance.

Main Results:

• The synthesized F6D demonstrated a higher Tg, complementary absorption, and cascade energy levels.
• F6D exhibited excellent miscibility and intermolecular interactions with the host materials (PM6 and Y6).
• The ternary device achieved a champion power conversion efficiency of 17.52% and showed superior stability under heating and lighting.

Conclusions:

• The rational molecular design of F6D effectively enhances the thermal stability of organic solar cells.
• Ternary organic solar cells incorporating F6D offer a promising strategy for achieving both high efficiency and operational stability.
• F6D represents a valuable material for advancing the practical application of organic solar cell technology.