Y6 Organic Thin-Film Transistors with Electron Mobilities of 2.4 cm² V^-1 s^-1 via Microstructural Tuning

There is a growing demand to attain organic materials with high electron mobility, μ_e , as current reliable reported values are significantly lower than those exhibited by their hole mobility counterparts. Here, it is shown that a well-known nonfullerene-acceptor commonly used in organic solar cells, that is, BTP-4F (aka Y6), enables solution-processed organic thin-film transistors (OTFT) with a μ_e as high as 2.4 cm²  V^-1  s^-1 . This value is comparable to those of state-of-the-art n-type OTFTs, opening up a plethora of new possibilities for this class of materials in the field of organic electronics. Such efficient charge transport is linked to a readily achievable highly ordered crystalline phase, whose peculiar structural properties are thoroughly discussed. This work proves that structurally ordered nonfullerene acceptors can exhibit intrinsically high mobility and introduces a new approach in the quest of high μ_e organic materials, as well as new guidelines for future materials design.