Enhancing the interfacial interaction of carbon nanotubes fibers by Au nanoparticles with improved performance of the electrical and thermal conductivity

The enhanced interfacial interaction between carbon nanotubes (CNTs), and thus the promoted interfacial thermal transport (ITT), are keys to improve the efficiency of CNT-assembled thermo-functional devices and materials, including energy transmission medium and thermal interface materials. Here, by using the intriguing CNT fibers decorated with Au nanoparticles (NPs) as a promising platform, we attain to the underlying mechanism for the remarkably boosted ITT of CNT/Au/CNT contacts. The enhancement is ascribed to the NP-induced excitation of low-frequency phonon (LFP) modes in CNTs, a strong mechanism to redistribute LFP modes into the interfacial carbon atoms and then to activate a resonance with the LFPs of Au NPs, resulting in more heat transfer across the contact. Furthermore, the Au NP/CNT fiber also exhibits an enhanced interfacial electrical transport, owing to the extraction of highly degenerate electronic density of states near the van Hove singularities, and thus induces an equivalent p-type doping for the CNTs. The present study demonstrates a new strategy to develop multifunctional CNT fibers with enhanced electrical and thermal conductivities.