Tuning electronic and optical properties of 2D polymeric C₆₀ by stacking two layers

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Few-layer fullerene networks exhibit enhanced stability due to van der Waals interactions.
• Experimentally, few-layer fullerene networks are more accessible than monolayer polymeric C60.
• Systematic theoretical studies on few-layer C60 networks are lacking.

Purpose of the Study:

• To theoretically investigate and compare the structural, electronic, and optical properties of bilayer and monolayer fullerene networks.
• To explore the impact of interlayer van der Waals interactions on material properties.
• To identify strategies for tuning the properties of 2D polymeric C60.

Main Methods:

• Density Functional Theory (DFT) calculations.
• Comparative analysis of structural, electronic, and optical properties.
• Investigation of band structure, band-edge positions, effective mass, and exciton absorption.

Main Results:

• Band gap and band-edge positions are largely unchanged in bilayer C60 networks compared to monolayers, maintaining photocatalytic efficiency.
• Interlayer interactions in bilayers lead to varied effective mass ratios, enhancing anisotropy in carrier transport.
• Bilayer fullerene networks exhibit stronger exciton absorption across the visible spectrum and increased polarization dependence in optical absorption.

Conclusions:

• Few-layer fullerene networks, particularly bilayers, show significant potential for advanced applications in photovoltaics and photonics.
• Stacking degrees of freedom provide a viable strategy to tailor the electronic and optical properties of 2D polymeric C60.
• The enhanced optical properties and carrier transport anisotropy of bilayer fullerene networks offer unique opportunities for device engineering.