Chlorination: An Effective Strategy for High-Performance Organic Solar Cells

Area of Science:

• Materials Science
• Organic Electronics
• Photovoltaics

Background:

• Polymer solar cells (PSCs) are a promising renewable energy technology.
• Improving the efficiency and stability of PSCs is crucial for commercialization.
• Halogenation, particularly chlorination, has emerged as a key strategy to enhance PSC performance.

Purpose of the Study:

• To summarize recent advancements in PSCs utilizing a chlorination strategy.
• To elucidate the intrinsic properties of chlorine atoms and their impact on material characteristics.
• To explore the synergistic effects of chlorination with other methods for improved solar energy conversion.

Main Methods:

• Review of recent literature on chlorinated polymers and small molecules for PSCs.
• Analysis of the electronic and structural effects of chlorine substitution in donor-acceptor (D-A) materials.
• Discussion of noncovalent interactions (e.g., Cl···S, Cl···π) induced by chlorination.

Main Results:

• Chlorination effectively modulates the electronic properties of D-A materials, enhancing intramolecular and intermolecular interactions.
• Chlorine's unique electronic structure (empty 3d orbits) facilitates electron pair and π-electron acceptance, down-shifting molecular energy levels.
• Synergistic effects of chlorination with other strategies lead to significant improvements in solar conversion efficiency.

Conclusions:

• Chlorination is a powerful strategy for tuning material properties to boost PSC performance.
• Understanding chlorine's role in noncovalent interactions and energy level modulation is key to designing high-performance solar devices.
• This review provides a clearer pathway for researchers to select appropriate substitution methods for optimizing PSCs.