Flat electronic band structure and anisotropic optical, mechanical, and thermoelectric properties of two-dimensional fullerene networks

TL;DR

This study investigates the electronic, optical, mechanical, and thermoelectric properties of a novel two-dimensional fullerene monolayer, revealing its potential for diverse applications due to its unique anisotropic characteristics.

Contribution

It provides a comprehensive first-principles analysis of a newly synthesized 2D fullerene monolayer, highlighting its flat band structure and anisotropic properties, which were not previously characterized.

Findings

Alpha-C60-2D has a direct bandgap of 1.49 eV.

It exhibits strong optical absorption in the long-wave ultraviolet region.

The material shows large hole mobility and ultrahigh Seebeck coefficient.

Abstract

Nanoclusters like fullerenes as the unit to build intriguing two-dimensional topological structures is of great challenge. Here we propose three bridged fullerene monolayers and comprehensively investigate the novel fullerene monolayer as synthesized experimentally Zheng et al.,[Nature 606, 507-510 (2022)] by state of the art first principles calculations. Our results show that alpha-C60-2D has a direct bandgap of 1.49 eV owing to a flat conduction band bottom close to the experimental value, the optical linear dichroism with strong absorption in long-wave ultraviolet region, a small anisotropic Youngs modulus, the large hole mobility, and the ultrahigh Seebeck coefficient at middle low temperatures. Moreover, Li ions are found to migrate easily along the X path in alpha-C60-2D. It is unveiled that the anisotropic optical, mechanical, electrical, and thermoelectric properties of alpha-C60-2D originate from the asymmetric bridging arrangements between C60 clusters. Our study promises potential applications of monolayer fullerene networks in diverse fields.