Confined synthesis and thermal conductivity of deuterated graphene nanoribbons

In contrast to gapless graphene, armchair graphene nanoribbons (AGNRs) exhibit a width-dependent band gap. Theoretical calculations predicted that the thermal conductivity of graphene nanoribbons (GNRs) is significantly lower than that of graphene and can be customized through isotopic labeling. However, experimental validation of this phenomenon is still challenging. In this study, hydrogen-terminated 6-AGNRs and deuterated 6-AGNRs with varying deuteration ratios were synthesized inside single-walled carbon nanotubes. By applying Raman spectroscopy, the thermal conductivity of 6-AGNRs was determined to be approximately 1150 W m-1 K-1 , which is only one third of graphene and is consistent to the theoretical prediction. Furthermore, the thermal conductivity of deuterated 6-AGNRs is reduced by more than 50 % compared to that of the 6-AGNRs, suggesting an effective route to modulate the thermal conductivity of GNRs, in addition to the width and edge structure of the GNRs.