Electronic and thermal conduction properties of halogenated porous graphene nanoribbons

TL;DR

This study uses density functional theory to explore how halogen passivation affects the electronic and thermal properties of porous graphene nanoribbons, aiming to optimize thermoelectric performance.

Contribution

It provides a comparative analysis of armchair and zig-zag halogenated porous graphene nanoribbons, revealing tunable electronic and thermal properties through halogen type and pore size.

Findings

Thermal gaps shift to lower energies with heavier halogens.

Electronic gaps decrease as halogen atomic number increases.

Halogen passivation enables tuning of thermoelectric properties.

Abstract

In the framework of density functional theory (DFT) calculations we investigate the electronic and thermal properties of porous graphene (PG) structures passivated with halogen atoms as possible candidates for efficient thermoelectric devices. Armchair and zig-zag halogenated PG nanoribbons are analyzed comparatively. The electronic properties are consistent with the expected behavior for the two types of terminations, however with marked influences introduced by the different halogen atoms. Depending on the pore sizes and halogen type pseudo-gaps in the phononic band structure are visible in the low frequency range, which are particularly important for the thermal conduction at low temperatures. The gaps are systematically displaced towards lower energies as the atomic number of the halogen increases. At the same time, the electronic gap decreases, which is also essential for attaining a large figure of merit in a thermoelectric device. This indicates the possibility of tuning both electronic and thermal properties of PG structures by halogen passivation.