Selective Dispersion of Large-Diameter Semiconducting Carbon Nanotubes by Functionalized Conjugated Dendritic Oligothiophenes for Use in Printed Thin Film Transistors

Selective dispersion of semiconducting single walled carbon nanotubes (s-SWCNTs) by conjugated polymer wrapping is recognized as the most promising scalable method for s-SWCNT separation. Despite a number of linear conjugated polymers being reported for use in s-SWCNT separation, these linear polymers suffer batch-to-batch variation for their undefined molecular structure. Here, it is reported that conjugated dendritic oligothiophenes with multiple diketopyrrolopyrrole groups at the periphery have the capability of selectively dispersing large diameter s-SWCNTs with high dispersion efficiency and certain chiral selectivity. Printed top-gated thin film transistors using the dendrimer sorted s-SWCNTs show high charge carrier mobility of up to 57 cm(2) V-1 s(-1) and on/off ratios of approximate to 10(6) with high reproducibility, which is ascribed to the defined and monodispersed molecular structure of dendrimers. Moreover, owing to the multiple peripheral anchoring groups of these dendritic molecules, these dendrimer-s-SWCNT dispersions display excellent stability. The current work proves that dendritic molecules are excellent dispersion reagents for s-SWCNT separation.