High‐Performance Polymer‐Small Molecule Blend Organic Transistors

Abstract

A double‐gate device is used to demonstrate that a blended formulation of semiconducting small molecules and a polymer matrix can provide high electrical performance within thin‐film field‐effect transistors (OTFTs) with charge carrier mobilities of greater than 2 cm2 V−1 s−1, good device‐to‐device uniformity, and the potential to fabricate devices from routine printing techniques.

Small Molecule/Polymer Blend Organic Transistors with Hole Mobility Exceeding 13 cm2 V−1 s−1

“…This vertical phase separation correlates with previously reported blend systems [13] [14] [20] making the C8-BTBT:C16IDT-BT:C60F48(1%) ideal for use in top-gate OTFTs. Interestingly, we find that the signal corresponding to the C60F48 appears almost entirely within the C16IDT-BT layer located closer to the bottom interface (blend/substrate).…”

“…[17] [18] Blending small molecules with polymers has been shown to combine the high electrical performance traditionally associated with the small molecule with the superior filmforming attributes of the polymer, leading to semiconducting systems that combine the best of both worlds. [13] [14] [19] The 1 st generation blend was introduced in 2009 by Hamilton et al when they blended the small-molecule 2,8-difluoro-5,11-bis(triethylsilylethynyl)anthradithiophene (diF-TES ADT) with the semiconducting polymer poly(triarylamine) (PTAA), resulting in OFETs with mobilities of 2.4 cm 2 /Vs. [13] The excellent performance of the diF-TES ADT:PTAA blend is attributed to the vertical phase separation of the two material components that results in a layer of high mobility polycrystalline small-molecule on top of a layer of polymer that acts as a binder.…”

“…[13] [14] [19] The 1 st generation blend was introduced in 2009 by Hamilton et al when they blended the small-molecule 2,8-difluoro-5,11-bis(triethylsilylethynyl)anthradithiophene (diF-TES ADT) with the semiconducting polymer poly(triarylamine) (PTAA), resulting in OFETs with mobilities of 2.4 cm 2 /Vs. [13] The excellent performance of the diF-TES ADT:PTAA blend is attributed to the vertical phase separation of the two material components that results in a layer of high mobility polycrystalline small-molecule on top of a layer of polymer that acts as a binder. [ 4] [14] [20] This unique microstructure has been shown to reduce the energetic disorder in the transistor channel through the formation of conductive grain boundaries [21] that appear to mediate charge transport between polycrystalline domains.…”

“…This is a key observation that demonstrates the potential of this particular blend, indicating that blending C16IDT-BT with C8-BTBT results in passivation of grain-boundaries and improved hole-transport between C8-BTBT rich regions, in an analogous manner to the 1 st and 2 nd generation blend systems discussed earlier. [13], [14] The subsequent inferior OTFT operating characteristics will not be considered in detail here, however, we believe that the performance improves with lower ratios of small-molecule to polymer as this encourages miscibility between the two materials leading to an improved layer microstructure.…”

New Fused Bis-Thienobenzothienothiophene Copolymers and Their Use in Organic Solar Cells and Transistors

“…As deposited electrode structures were then treated with the contact work function modifier monolayer agent pentafluorobenzenethiol (PFBT). 12 The glass/electrodes substrates were then transferred into a nitrogen glove-box in order to complete the remaining device fabrication and electrical characterization stages. Polymer layers were spin-cast from hot (100 °C) ODCB on top of the substrates and annealed at 120 °C for 15 min.…”