Polythiophene Derivative with Phenothiazine−Vinylene Conjugated Side Chain:  Synthesis and Its Application in Field-Effect Transistors

A new polythiophene derivative with phenothiazine−vinylene (PTZV) conjugated side chains, PTZV−PT, was synthesized through the Stille coupling reaction and characterized by 1H NMR, elemental analysis, GPC, TGA, DSC, UV−vis absorption spectroscopy, photoluminescence spectroscopy, and cyclic voltammetry. The polymer is soluble in common organic solvents and possesses good thermal stability with 5% weight loss at the temperature of 397 °C and T g of 140 °C. The weight-average molecular weight of PTZV−PT was 5.45 × 104 with the polydispersity index of 1.48. The absorption spectrum of PTZV−PT film displays a broad plateau between 300 and 600 nm. The hole mobility of PTZV−PT determined from space-charge-limited current model was 4.7 × 10-3 cm2 V-1 s-1. The field effect hole mobility of the polymer reached 6.8 × 10-3 cm2 V-1 s-1 with an on/off ratio of 2.5 × 104, which is among the best performance of the regiorandom polymers for the solution-processed organic field effect transistors (OFETs). The preliminary results indicate that PTZV−PT is a promising polymer material for applications in solution-processable OFETs.