Substrate-free, stretchable electrolyte gated transistors

Improving device deformability under mechanical stress is an essential requirement for the realization of next-generation wearable electronic applications. Herein, we report a new concept of stretchable thin-film transistors (TFTs) that can be fabricated without substrate components. Instead of using plastic substrates, we employ an elastic (and also free-standing) solid-state electrolyte as a gate insulator. The strategy not only realizes stretchable TFTs, but also enhances the device performance (e.g. mobility, operation voltage) by the formation of high-capacitance electric double layers. As source-drain electrodes, semi-circular shaped gold (Au) thin-film was employed to enhance the device stretchability. By the combination of a solid electrolyte (gate insulator), metal film (electrodes), and polymer semiconductor (channel layer), the device is stretchable up to around 10%, and shows typical p-channel switching performance with low operation voltage of 1 V and TFT mobility of about 0.81 cm2/V s. The devices were processed by a simple solution process and thermal evaporation under low temperature (