Exotic thermoelectric properties of coronene-cyclobutadienoid graphene nanoribbons

TL;DR

This paper presents coronene-cyclobutadienoid graphene nanoribbons as a new class of thermoelectric materials with high ZT values exceeding 2.1, achieved through unique edge structures and strain engineering, offering a lightweight and environmentally friendly alternative to traditional heavy-metal thermoelectrics.

Contribution

Introduces a novel design strategy for high-ZT thermoelectric materials using coronene-cyclobutadienoid graphene nanoribbons with exceptional low thermal conductivity and strain-tunable properties.

Findings

ZT exceeds 2.1 due to low phonon thermal conductivity

Electrical conductance and Seebeck coefficient are stable across edge structures

Strain can increase ZT to over 3.0

Abstract

Thermoelectric materials traditionally incorporate heavy metals to achieve low lattice thermal conductivity. However, elements such as Te, Bi, and Pb are costly and pose environmental hazards. In this study, we introduce a novel design strategy for thermoelectric materials, focusing on room-temperature, light-element, and high-ZT materials such as coronene-cyclobutadienoid graphene nanoribbons (cor4GNRs). This material demonstrates a ZT value exceeding 2.1, attributed to its exceptionally low phonon thermal conductivity resulting from its unique edge structure. Importantly, its electrical conductance and Seebeck coefficient remain relatively high and nearly unaffected by the edge structure. This distinct behavior in phonon and electronic transport properties leads to a remarkably high ZT value. Additionally, we discover that applying strain can significantly reduce phonon thermal conductivity, potentially increasing the ZT value to over 3.0. Our findings provide innovative insights for the design and application of advanced thermoelectric materials.