Controlled Assembly of Single-Walled Carbon Nanotubes into Thin Films and Their Applications

Single-walled carbon nanotubes (SWCNTs) exhibit excellent electrical, optical, and mechanical properties, making them great candidate materials for emerging applications such as high-performance electronics, transparent electrodes, and flexible sensors. The controlled assembly and organization into thin films, including random networks and aligned arrays, are critical for SWCNTs to fully demonstrate their performances. In the past three decades, with the development of growth, dispersing, and sorting SWCNTs, various deposition and assembly methods have been proposed and put into practice. Yet, the obtained films have not entirely met the requirements of high-end applications, especially for aligned arrays. This review comprehensively scrutinizes the methods for preparing SWCNT thin films from dispersions, including three ways to form random networks: adsorption on substrates, precipitation from dispersions, and vacuum filtration, and five ways to create aligned arrays: field-induced alignment, aggregation at interfaces and contact lines, well-controlled vacuum filtration, alignment by matrix deformation, and deposition on patterned substrates. In addition, the practices of directly depositing SWCNT thin films from the gas phase, represented by the floating catalyst chemical vapor deposition process, are also referred. These discussions about the achieved milestones and remaining challenges are expected to further inspire experimental designs and promote the application of SWCNT thin films.