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 H-1 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 degrees C and T-g of 140 degrees C. The weight-average molecular weight of PTZV-PT was 5.45 x 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 x 10(-3) cm(2) V-1 s(-1). The field effect hole mobility of the polymer reached 6.8 x 10(-3) cm(2) V-1 s(-1) with an on/off ratio of 2.5 x 10(4), 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.