Graphene Nanoribbon Based Thermoelectrics: Controllable Self- Doping and Long-Range Disorder.

Huashan Li,Jeffrey C Grossman

doi:10.1002/advs.201600467

Abstract

Control of both the regularity of a material ensemble and nanoscale architecture provides unique opportunities to develop novel thermoelectric applications based on 2D materials. As an example, the authors explore the electronic and thermal properties of functionalized graphene nanoribbons (GNRs) in the single‐sheet and helical architectures using multiscale simulations. The results suggest that appropriate functionalization enables precise tuning of the doping density in a planar donor/acceptor GNR ensemble without the need to introduce an explicit dopant, which is critical to the optimization of power factor. In addition, the self‐interaction between turns of a GNR may induce long‐range disorder along the helical axis, which suppresses the thermal contribution from phonons with long wavelengths, leading to anomalous length independent phonon thermal transport in the quasi‐1D system.

Highlights

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A type-III interface is established between the donor and acceptor graphene nanoribbons (GNRs), as shown by the crossing between the highest valence band (VB) of the donor and the lowest conduction band (CB) of the acceptor near the Γ point (Figure 2a–d)
While the shapes of the bands (Figure 2b–d) and the wavefunctions (Figure 2g–j) of donor/ acceptor GNRs are mainly preserved in the entire sheet as the ligands are only present near the edge of the GNRs, the absolute energy levels shift remarkably due to the potential alignment at the interface (Section B, Supporting Information), again indicating the importance of the ensemble regularity — precise control of the bandstructure requires precise control of the system architecture

Summary

Introduction

The MIT Faculty has made this article openly available. Please share how this access benefits you. The authors explore the electronic and thermal properties of functionalized graphene nanoribbons (GNRs) in the single-sheet and helical architectures using multiscale simulations.

Results

Conclusion