(Invited) Intrinsically-Stretchable, Transparent Thin Film Transistors

Abstract

Thin-film field effect transistor (TFT) is a fundamental component behind morden electronic devices including displays, sensor arrays, microprocessers, and identification tags. Here, we report the development of new conductor, semiconductor, and dielectric materials that exhibit elastomeric deformability and solution processability. A silver nanowire based screen printing ik was formulaed to print silver nanowire electrodes with conductivity as high as 47K S/cm which are embedded in an elastomer matrix to preserve the electrical conductivity at large strains. A semiconductive single-walled carbon nanotube network was employed as the channel material, and a polyurethane-co-polyethylene oxide as elastomeric dielectric. Intrinsically stretchable TFTs were fabricated using these new electronic materials. The fabrication processes involved the preparation of the source, drain and gate electrodes, semiconductor layer, dielectric layer, and substrate by solution-based techniques under ambient conditions. The resulting devices exhibited a mobility of ~30 cm2V-1s-1, on/off ratio of 103-104, switching current >100 mA, transconducance >50 mS, and relatively low operating voltages. The devices could be stretched by up to 50% strain while retaining a high mobility >10 cm2V-1s-1. No significant loss in electrical property was observed after 500 cycles of repeated stretching to 20% strain. The TFTs were used to drive organic light-emitting diodes with brightness controllable from 0 cd/m2 (off) to 200 cd/m2 (a typical display brightness). The approach and results represent an important progress toward the development of stretchable active matrix displays and other stretchable electronic devices.