Influence of Backbone Fluorination in Regioregular Poly(3-alkyl-4-fluoro)thiophenes

• DOI: 10.1021/jacs.5b02785
• Publication Date: 2015-05-21T11:11:52Z
• Authors: Zhuping Fei; Pierre Boufflet; Sebastian Wood; Jessica Wade; John Moriarty; Eliot Gann; Erin L. Ratcliff; Christopher R. Mc...; Henning Sirringhaus; Ji-Seon Kim; Martin Heeney
• Keywords: Fluorine; Organosilicon

We report two strategies toward the synthesis of 3-alkyl-4-fluorothiophenes containing straight (hexyl and octyl) branched (2-ethylhexyl) alkyl groups. demonstrate that treatment dibrominated monomer with 1 equiv Grignard reagent leads to formation a single regioisomer as result pronounced directing effect fluorine group. Polymerization resulting species affords highly regioregular poly(3-alkyl-4-fluoro)thiophenes. Comparison their properties those analogous non-fluorinated polymers shows backbone fluorination an increase in polymer ionization potential without significant change optical band gap. Fluorination also results enhanced tendency aggregate solution, which is ascribed more co-planar on basis Raman DFT calculations. Average charge carrier mobilities field-effect transistors are found by up factor 5 for fluorinated polymers.