Recent Progress in Chlorinated Organic Photovoltaic Materials

Area of Science:

• Materials Science
• Organic Photovoltaics (OPV)
• Chemical Engineering

Background:

• Organic photovoltaic (OPV) cells have achieved power conversion efficiencies (PCEs) exceeding 17%, nearing commercialization.
• Designing cost-effective materials with superior performance is critical for OPV technology advancement.
• Chlorinated materials are emerging as high-performance alternatives to traditional fluorinated compounds in OPVs.

Purpose of the Study:

• To provide a comprehensive guideline for the molecular design of chlorinated OPV materials.
• To highlight the advantages of chlorinated materials over their fluorinated counterparts.
• To review the current state and future potential of chlorinated OPV materials.

Main Methods:

• Analysis of the fundamental properties of the chlorine atom in organic semiconductors.
• Comparison of optical and electrical property modulation by chlorination versus fluorination.
• Review of existing chlorinated OPV materials (donors and acceptors) and their device performance.

Main Results:

• Chlorination more effectively modulates optical/electrical properties, leading to lower energy levels and broader absorption spectra compared to fluorination.
• The larger atomic size of chlorine can enhance π-electron overlap, improving intermolecular packing and charge transport, but may also cause undesirable twisting.
• Chlorination offers a cost-effective synthetic route, potentially reducing overall OPV material costs.

Conclusions:

• Chlorinated OPV materials demonstrate significant potential for high PCEs, improved voltage, and current density.
• Strategic molecular design considering chlorine's atomic properties is key to maximizing performance benefits.
• Chlorination represents a vital strategy for developing next-generation, high-performance, and economically viable OPV technologies.