Synthesis and characterization of the regiorandom homopolymer of 3-alkyldithieno[3,2-b:2′,3′-d]thiophene for thin-film transistors

A regiorandom homopolymer of 3-alkyldithieno[3,2-b:2',3'-d]thiophene (P3ADTT) has been prepared by oxidative polymerization using Iron(III) Chloride and oxygen as oxidants. The physical and electrochemical properties of the homopolymer were investigated and compared with those of P3HT. Its application in organic field-effect transistors showed annealing-free hole mobility up to 0.048 cm(2) V-1 s(-1) at room temperature and a significant thermally stable mobility of 0.13 cm(2) V-1 s(-1) at 200 degrees C with a current on/off ratio of greater than 10(5).