Enhancing the interfacial thermal conduction of the graphene sheets via chemical bond–bond connections

Min-Shan Li,Kai-Xuan Chen,Shu-Shen Lyu,Dong-Chuan Mo,Yuan-Xiang Fu

doi:10.1063/1.5113973

Abstract

Graphene, after its discovery in 2004, was known to possess extremely high thermal conductance. In the practical applications, however, the thermal conductance was unfortunately low compared with its theoretical value since the heat transfer among individual graphene sheets is largely hindered by the boundary phonon dissipation. In this first-principles study, we propose a new strategy to enhance the interfacial thermal transport, that is, chemical bond–bond connections. Organic, metal and metal-oxide groups are adopted to link two graphene nanoribbons, acting as a thermal bridge. In such models, the thermal conductance is significantly enhanced, as compared with the non-linked counterparts in which the van der Waals interactions dominate. In numbers, the highest thermal conductance of 0.577 GW·m–2·K–1 at 300K (which preserves as much as 13.2% compared with the pristine nanoribbon) can be obtained when linked by –Al– groups. The enhancement mechanism as regards different bond–bond connections is also discussed. Our study paves the way to exploring the enhancement of interfacial heat transfer. Even though the work was done based on the graphene models, it can be generally extended to a variety of inorganic and organic families.

Highlights

INTRODUCTIONWith the fast advancement in the modern electronics, the efficiency of the heat transfer has become an urgent issue in the highly integrated chips.[1,2] The star material graphene[3,4,5,6] has attracted substantial attentions due to its ultra-high thermal conductivity[7,8,9] and been considered as a promising candidate to provide highperformance heat transfer.[10–13] For example, graphene is widely used as filler in various polymer products to improve their heat transfer performance.[14–19] such enhancement is hindered in the practical applications due to the phonon boundary dissipation, especially among graphene sheets.[20,21]
For hydrogenated zigzag graphene nanoribbon (h-ZGNR) with a gap larger than 2.7 Å, most modes possess a zero phononic transmission, indicating that phonon vibration can barely pass through the van der Waals (vdW) gap
We investigated the thermal transport across the interface of bond connected graphene nanoribbon sheets using density functional theory (DFT) and non-equilibrium Green’s function (NEGF) method

Summary

INTRODUCTION

With the fast advancement in the modern electronics, the efficiency of the heat transfer has become an urgent issue in the highly integrated chips.[1,2] The star material graphene[3,4,5,6] has attracted substantial attentions due to its ultra-high thermal conductivity[7,8,9] and been considered as a promising candidate to provide highperformance heat transfer.[10–13] For example, graphene is widely used as filler in various polymer products to improve their heat transfer performance.[14–19] such enhancement is hindered in the practical applications due to the phonon boundary dissipation, especially among graphene sheets.[20,21]. With the fast advancement in the modern electronics, the efficiency of the heat transfer has become an urgent issue in the highly integrated chips.[1,2] The star material graphene[3,4,5,6] has attracted substantial attentions due to its ultra-high thermal conductivity[7,8,9] and been considered as a promising candidate to provide highperformance heat transfer.[10–13] For example, graphene is widely used as filler in various polymer products to improve their heat transfer performance.[14–19] Such enhancement is hindered in the practical applications due to the phonon boundary dissipation, especially among graphene sheets.[20,21]. Our main topic is to investigate the in-plane interfacial thermal transport among graphene nanoribbons linked by organic (–OOC–C2H4–COO–, –OOC–C6H4–COO–, –O–C6H4–COO–), metal (–Al–, –Cr–, –Mo–) and metal-oxide groups (–O–Al–O–) using density functional theory (DFT) and non-equilibrium Green’s function method. The thermal conductance enhancement induced by chemical bond–bond connection is mirrored in the phononic transmission

MODEL AND COMPUTATIONAL METHOD

RESULTS AND DISCUSSION

CONCLUSION