Ultra-high mobility in defect-free poly(3-hexylthiophene-2,5-diyl) field-effect transistors through supra-molecular alignment

Performance enhancement of organic field-effect transistors (OFETs) based on solution-processable conjugated polymers (CPs) holds critical significance for the realization of cost-effective commercial applications such as organic light-emitting diode displays. One of the most critical performance parameters is the charge-carrier field-effect mobility (μFET) that is significantly influenced by the molecular arrangement in a CP. In this article, floating film transfer method (FTM) is utilized for the deposition of a CP––defect-free poly(3-hexylthiophene-2,5-diyl) (DF-P3HT)––which results in the formation of aligned supra-molecular assemblies. When applied as the active layer in OFET devices, μFET reaching as high as 8.0 cm2/V.s (6.3 cm2/V.s on average) is obtained. The value of μFET observed in the current study is the highest value reported so far for P3HT based OFETs (∼5 times higher as compared to when DF-P3HT is deposited using spin coating).