A paper-based piezoelectric touch pad integrating zinc oxide nanowires

This paper describes a new type of paper-based piezoelectric touch pads integrating zinc oxide nanowires (ZnO-NWs), as user interfaces in paper-based electronics. The functionality of the touch pads is enabled by the piezoelectric property of ZnO-NWs grown on paper using a simple hydrothermal method. A piece of ZnO-NW paper with two screen-printed silver electrodes forms a touch button, and touch-induced electric charges from the button is converted into a voltage signal using a charge amplifier circuit. A touch pad consisting of an array of buttons can be readily integrated into paper-based electronic devices, allowing user input of information for various purposes such as programming, identification checking, and gaming. This novel design features ease of fabrication, low cost, and ultra-thin structure, and good compatibility with techniques in printed electronics, which further enriches the tool set available for developing paper-based electronic devices.