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 (μ h ) is 6.31 cm 2 V –1 s –1 and the electron mobility (μ e ) is 0.78 cm 2 V –1 s –1 . Moreover, high μ h and μ e values of 4.15 and 0.34 cm 2 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.