Site-Specific Growth and Printing of Nanowires for Resource Efficient Fabrication of Flexible Electronics.

Semiconducting nanowires (NWs) hold great potential for high-performance flexible electronics. However, using them, to fabricate electronic devices, is a complex process requiring multiple lithography steps to address the issues such as the one arising from mismatches between the temperatures needed for NW growth and the temperatures the polymeric substrates can withstand. Herein, a facile "design to fab" approach is presented, which avoids lithography-based fabrication by implementing the device layout at the NW synthesis level itself. This is demonstrated by synthesizing the arrays of ZnO NWs at pre-defined locations, followed by their direct printing on flexible substrates using custom contact printing method. The ZnO NWs-based printed nanoscale electronic layers exhibit excellent spatial uniformity (NW length, 18-26 µm) and alignment (88-96°). The patterned electronic layers are further processed (e.g., printed conductive tracks) at room temperature to develop proof of concept UV photodetectors. The presented approach significantly reduces the fabrication complexity by eliminating the lithography-related steps and lays the foundation for resource-efficient fabrication of NWs-based large-area flexible electronics.