Controllable Fabrication Of Chiral Single Walled Carbon Nanotube Films And Applications

Due to the unique one-dimensional structure,single-walled carbon nanotubes?SWNTs?integrate excellent electrical and mechanical properties,which make them a promising material in many fields.However,owing to the diversity of the structure of SWNTs,most of the SWNTs prepared are mixtures with many chiral species,which greatly hinder the performance of the intrinsic excellent properties of carbon nanotubes.Selective dispersion using polymer wrapping only requires a simple process with high selectivity and high yield,which is considered to be one of the most promising methods.Moreover,fine-tuning of the dispersing properties through polymer design could obtain different chiral species.Recently,the main problems of the polymer separation method are the rare chiral species obtained and the low yield,which make it difficult to prepare the high-quality thin film for effective devices.With to goal to promote the application of SWNTs in devices with high-performance and high-uniformity,monodisperse single-chiral SWNT solutions were obtained by selecting the suitable polymer as the dispersant and the mechanism for the selective extraction has been discussed.Furthermore,chiral carbon nanotubes film with high-density and high-uniformity were fabricated,as well as high-performance thin-film transistors?TFTs?based on chiral SWNTs.Finally,the application of mono-chiral carbon nanotubes in electrochromic devices was preliminarily studied.The main results of this thesis are as follows:1.Extraction of single-chirality SWNTs with high purity assisted by three polymers of PFP?PCP?F8BT.Through the analysis of the chain structure and electronic structure of the polymers,we believe that the selective extraction of specific chiral SWNTs by the polymers can be attributed to the synergistic effect of the structure matching and the energy level matching between polymers and SWNTs.Moreover,the optimum selective conditions were determined when PFP served as the dispersant.2.The controllable preparation of chiral single-wall carbon nanotube thin films was realized by optimized immersed deposition.And single-chirality SWNT solution with high concentration is the key factor for the preparation of high-quality chiral SWNT films.Finally,chiral SWNTs film with high density of?36±3?tubes/?m were acquired by using effective flocculation method to concentrate the chiral SWNT solution.3.Realization of the application of?10,8?SWNTs on TFT arrays.The TFTs were fabricated with high mobility of 57.9 cm²·V^-1·s^-1 and on/off ratio around 10⁶,which locates the highest level compared to the reported enriched chiral SWNTs.Moreover,the preliminary investigation was carried out for the application of single chiral carbon nanotubes in electrochromic devices.