Transistor application of new picene-type molecules, 2, 9-dialkylated phenanthro[1, 2-b:8, 7-b′]dithiophenes. Issue 10 (30th January 2015) - Kubozono, Yoshihiro
Abstract : Field-effect transistors have been fabricated that use thin films of 2, 9-dialkylated phenanthro[1, 2- b :8, 7- b ′]dithiophenes (C n -PDTs), with the transistor based on a thin film of C12 -PDT showing a μ as high as ∼2 cm 2 V −1 s −1, which is promising for future practical electronics. Abstract : Field-effect transistors (FETs) have been fabricated with thin films of a series of 2, 9-dialkylated phenanthro[1, 2- b :8, 7- b ′]dithiophene derivatives (C n -PDTs). The FET characteristics of C n -PDT thin-film FETs with an SiO2 gate dielectric as well as high- k gate dielectrics were recorded, and the dependence of the field-effect mobility, μ, on the number ( n ) of carbon atoms in the alkyl chains was investigated, showing that the 2, 9-didodecylphenanthro[1, 2- b :8, 7- b ′]dithiophene (C12 -PDT) thin-film FET displays superior properties, with μ s as high as 1.8 cm 2 V −1 s −1 for the SiO2 gate dielectric and 2.2 cm 2 V −1 s −1 for the HfO2 gate dielectric. The average μ values, 〈 μ 〉, reach 1.1(5) and 1.8(6) cm 2 V −1 s −1, respectively, for the SiO2 and ZrO2 gate dielectrics. Low-voltage operation, showing an absolute average threshold voltage 〈| V th |〉 of ∼11 V, was implemented, together with the above high 〈 μ 〉 of ∼2 cm 2 V −1 s −1 . Also, a flexible FET was fabricated with a parylene gate dielectric. The results of this study show the potential of the C12 -PDT molecule for application in a high-performance transistor.