Gram‐scale carbon nanotubes as semiconducting material for highly versatile route of integration in plastic electronics

A versatile chemical functionalization of single‐walled carbon nanotubes (SWNT) is developed to eliminate the conductivity of metallic SWNTs in pristine SWNT mixtures, without sorting. Thanks to the high selectivity of the diazoether reagent, metallic SWNTs can be functionalized while preserving the transport properties of semiconducting SWNTs, even in nonindividually dispersed SWNT solutions. In this way, liters of aqueous semiconducting ink for printing or spray can be prepared at the laboratory scale and used for the fabrication of thin‐film transistors (TFT) by spraying. Diazoether grafting also improved SWNT dispersion by preventing rebundling. Consequently, while less conductive than pristine SWNTs, diazoether‐treated SWNTs provided higher TFT transconductance thanks to a more homogeneous percolation in the film. SWNT TFTs made on wafer and plastic with pristine and diazoether‐treated SWNTs were compared. Sprayed films of diazoether treated, unsorted SWNTs provided TFTs with I_ON/I_OFF around 500, about 2 orders of magnitude higher than pristine SWNT TFTs. Mobilities were similar, up to 1 cm²/V s. Interestingly, diazoether‐treated SWNT TFTs kept a high I_ON/I_OFF in a wide range of SWNT density and channel length, where pristine SWNT films became metallic.