High-mobility amorphous PTB7 organic transistors enabled by high-capacitance electrolyte dielectric

Abstract

Molecular engineering of organic semiconductors through different synthetic routes has remarkably improved the understanding of the structure-property relationship and charge transport physics, particularly in organic field-effect transistors (OFETs). Emerging OFETs with reliable charge-carrier mobilities exceeding >1cm(2) V-1 s(-1) have been demonstrated. However, the field-effect mobilities of amorphous conjugated polymer semiconductors have still showed the values below 10(-2) cm(2) V-1 s(-1) over the past two decades. Here, we report on highly reproducible amorphous organic PTB7 transistors with an exceptional mobility of 0.80cm(2) V-1 s(-1) (mu(avg) approximate to 0.51 +/- 0.16cm(2) V-1 s(-1)) operating at 2V comparable to that of inorganic amorphous silicon semiconductor devices (0.5-1cm(2) V-1 s(-1)). This remarkable performance is enabled by the use of high-capacitance electrolyte dielectric (C-i = 48.42 mu F cm(-2)), allowing easily attainable lower contact resistance of<400 Omega cm and improved charge carrier density in the transistor channel, compared to those fabricated using low-k poly(methyl methacrylate) (C-i = 6.2 nF cm(-2)) and high-k poly(vinylidene fluoride-co-hexafluoropropylene) (C-i = 49.8 nF cm(-2)) gate dielectrics. This work contributes an opportunity for understanding and improving device performances of amorphous conjugated polymer semiconductors. Published under an exclusive license by AIP Publishing.