Dielectric field assisted one step sorting and large area thin film fabrication with single-walled carbon nanotube

Abstract

Single-walled carbon nanotubes (SWNTs) are promising candidate as next-generation material for transistor due to their high charge carrier mobility, band-gap controllability, solution processability, and flexibility. However, due to the difficulty of control chirality, direction and density of SWNTs, It has not been used in industry for more than decade. in particular, chirality control is an important factor for determining whether a transistor operates or not. There are several processes that have been announced, but they have problems that take too long or limitation for the solvent. Herein, we present a one step process for control both chirality and density for SWNTs by using dielectric field. Metallic SWNTs are preferentially aligned and deposited by the dielectric filed. We focused for remaining SWNTs that non-deposited by dielectric field for enrich the semiconducting SWNTs. The schematic for one step sorting and large area film fabrication is in bellow. If unsorted solution is injected to inlet of fluidic channel by the syringe pump, due to dielectric field, electrodes attract metallic SWNTs and semiconducting enriched solution is come out from the outlet. The efficiency of enrichment is proportional to the path with dielectric field. We combined this fluidic channel with shearing blade to continuously supply sorted solution. The solution comes out for dielectric field assisted fluidic channel is spread out between blade edge and substrate by the capillary phenomenon and make meniscus. This meniscus is maintained with steady state due to continuous supply and form uniform thin film of semiconducting SWNTs. By this process, we can get large area semiconducting SWNTs thin film by one step and this process can be used with polar solvent like water. We project that our process can be used other materials need sorting and large area film