Crossover from band-like to thermally activated charge transport in organic transistors due to strain-induced traps

Significance The operation of organic field-effect transistors is governed by the processes taking place at the device interfaces. The mismatch in the coefficients of thermal expansion of the consecutive layers can induce inhomogeneous strain in the organic semiconductor layer and reduce performance by increasing the electronic trap density. We show that a high-quality organic semiconductor layer is necessary, but not sufficient, to obtain efficient charge-carrier transport, and we propose a device design strategy that allows us to achieve the intrinsic performance limits of a given organic semiconductor regardless of the relative thermal expansions of the constituent layers.