Dispersion of High‐Purity Semiconducting Arc‐Discharged Carbon Nanotubes Using Backbone Engineered Diketopyrrolopyrrole (DPP)‐Based Polymers

The isolation of semiconducting single‐walled carbon nanotubes (sc‐SWNTs) with ideal diameter and high purity is highly desired for high‐performance electronic devices. However, current sorting methods for large‐diameter sc‐SWNTs suffer from either low purity (<99%) or long processing time (>20 h). Here, a backbone‐engineering strategy is reported for the polymer used for sorting to improve the purity of sorted sc‐SWNTs. Six diketopyrrolopyrrole (DPP)‐based conjugated polymers are used to systematically investigate their sorting ability for sc‐SWNTs. It is found that incorporation of more thiophenes building blocks in the repeating units of DPP polymer backbone leads to increased selectivity and yield for sc‐SWNTs. The DPP polymers can disperse sc‐SWNTs with 1.4–1.6 nm in diameter and high purity of 99.6% by a processing time as short as 1 h. Furthermore, a scalable film coating method named “solution shearing” is used to fabricate SWNT network thin‐film transistors (TFTs). The TFT devices exhibit both high mobilities over 50 cm 2 V −1 s −1 and high on/off ratios over 10 5 , which are among the highest performance for solution‐processed SWNT network TFTs.