Filled carbon-nanotube heterostructures: from synthesis to application

Abstract

Carbon nanotubes (CNTs) have a one-dimensional (1D) hollow tubular structure formed by graphene curling with remarkable electronic, optical, mechanical, and thermal properties. Except for the applications based on their intrinsic properties, such as electronic devices, THz sensors, and conductive fiber, CNTs can also act as nano-vessels for nano-chemical reactions and hosts for encapsulating various materials to form heterostructures. In this review, we have summarized the research status on filled carbon-nanotube heterostructures from four aspects: synthesis, morphological and electronic structure analysis, potential applications, and perspective. We begin with an overview of the filling methods and mechanisms of the 1D heterostructures. Following that, we discuss their properties in terms of morphological and electronic structure. The burgeoning applications of 1D heterostructures in nano-electronic, energy, storage, catalysis, and other fields are then thoroughly overviewed. Finally, we offer a brief perspective on the possible opportunities and challenges of filled CNTs heterostructures.