Flexible and Printed 3D Organic Integrated Circuits and Active-Matrix Sensor Arrays

Direct printing of thin-film transistors has enormous potential for ubiquitous and lightweight wearable electronic applications. This talk presents our recent advances in flexible and printed integrated circuits and active-matrix sensor arrays. First, A 3D integration approach is introduced to achieve technology scaling in printed transistor density, analogous to Moore’s law driven by lithography. We demonstrate the scalable 3D integration of single- and dual-gate organic transistors on plastic foil by printing with high yield, uniformity, and year-long stability. The vertical stacking of three complementary transistors enables us to propose a programmable 3D logic array as a new route to design printed flexible digital circuitry essential for emerging applications. Second, we use our robust TFT printing process to design and fabricate wearable active-matrix sensor arrays. We fabricate active-matrix TFT arrays with high yield and uniformity where array sizes can be customizable and integrate them with highly sensitive piezoresistive sheets. We maximize the pressure sensitivity and achieve nano-watt power consumption simultaneously by strategically modulating the TFT operation voltage. The sensor array creates a spatiotemporal pulse wave map on the wrist and overcomes the positional inaccuracy of conventional single-point sensors.