Carbon Nanotube with Chemically Bonded Graphene Leaves for Electronic and Optoelectronic Applications

Hybrid nanomaterials composed of carbon nanotubes (CNTs) and graphene could potentially display outstanding properties that are superior to either CNTs or graphene alone. However, the inherent CNT-graphene loose junctions present in the CNT-graphene composites synthesized by existing methods significantly hinder the realization of the full potential held by CNT-graphene hybrids. In this letter, we report on a brand-new, three-dimensional (3D) carbon nanostructure comprising few-layer graphene (FLG) sheets inherently connected with CNTs through sp(2) carbons, resembling plant leaves (FLGs) growing on stems (CNTs). The resulting hybrid nanostructures were characterized using scanning electron microscopy, transmission electron microscopy (TEM), Raman spectroscopy, and X-ray photoelectron spectroscopy. The evolution of FLG sheets on CNTs was tracked by high-resolution TEM. Distinct from a random mixture of CNTs and graphene sheets (CNT+G) suffering from poor CNT-graphene contacts, our CNT-FLG structure has intrinsic chemical bonding between the two constituent components. We further show that the resulting CNT-FLG structure exhibits remarkable optoelectronic and gas sensing properties superior to its CNT or CNT+G counterparts. The new structure reported here is thus attractive for various electronic and optoelectronic applications.