Two-dimensional copolymers with D-A type side chains for organic thin-film transistors: Synthesis and properties

This paper reports the synthesis, characterization and field-effect transistor (FET) properties of two new two-dimensional (2D) polymers, P1 and P2. The conjugated polymers were constructed by electron-rich main chains and D-A type side chains. DSC and XRD measurements revealed the amorphous nature of the polymer thin films and electrochemistry measurement results showed a low HOMO level of about -5.1 eV for both polymers. The polymers based solution-processed thin-film transistors with bottom-contact/bottom-gate geometry were fabricated with the films annealed at different temperatures to evaluate the FET performances. The hole mobilities were 3.6 x 10(-3) and 4.0 x 10(-3) cm(2) V-1 s(-1), with current on/off ratios of 1.0 x 10(5) and 2.0 x 10(5), for P1 and P2, respectively, at an annealing temperature of 160 degrees C when measured under ambient conditions, which are relatively good results for amorphous polymers.