Bioderived and Eco-Friendly Solvent-Processed High-Mobility Ambipolar Plastic Transistors through Controlled Irregularity of the Polymer Backbone

The development of top-performing π-conjugated polymers that can provide good solubility and processability in nontoxic solvents is imperative for the advancement of organic electronic devices. Herein, we report eco-friendly solution-processable semiconducting copolymers prepared by using two dithienylvinylene (TVT) and selenophene (Se) donor units in conjugation with diketopyrrolopyrrole (DPP) as an acceptor moiety. A series of the copolymers are fabricated with different TVT to Se composition ratios present in the DPP backbone that are represented by [10-0], [7-3], [5-5], [3-7], [2-8], [1-9], and [0-10]. Detailed structure–property investigations covering optical, electrochemical, morphological, and charge-transport properties with respect to the TVT/Se ratio in the copolymers are performed by a series of structural characterization techniques. The best ambipolar charge transport is obtained from [3-7] for which the hole mobility (μh) is 6.31 cm2 V–1 s–1 and the electron mobility (μe) is 0.78 cm2 V–1 s–1. Moreover, high μh and μe values of 4.15 and 0.34 cm2 V–1 s–1, respectively, are achieved for [3-7] devices processed from a bioderived, eco-friendly 2-methyltetrahydrofuran solvent. To the best of our knowledge, these are the highest recorded hole and electron mobilities for ambipolar organic field-effect transistors fabricated from a nonchlorinated solvent to date. Thus, this work is an important scientific step toward developing highly efficient green plastic transistors.