Alkyl group functionalization-induced phonon thermal conductivity attenuation in graphene nanoribbons**Project supported by the National Natural Science Foundation of China (Grant No. 11504418), China Scholarship Council Scholarship Program (Grant No. 201706425053), and the Fundamental Research Funds for the Central Universities of China (Grant No. 2015XKMS075).

Abstract

We calculated the room-temperature phonon thermal conductivity and phonon spectrum of alkyl group-functionalized zigzag graphene nanoribbons (ZGNRs) with molecular dynamics simulations. The increase in both chain length and concentration of alkyl groups caused remarkable reduction of phonon thermal conductivity in functionalized ZGNRs. Phonon spectra analysis showed that functionalization of ZGNR with alkyl functional groups induced phonon–structural defect scattering, thus leading to the reduction of phonon thermal conductivity of ZGNR. Our study showed that surface functionalization is an effective routine to tune the phonon thermal conductivity of GNRs, which is useful in graphene thermal-related applications.