Synergistic control of engineered nanostructures toward sensitivity and reliability of a flexible piezoresistive pressure sensor

Flexible pressure sensors are among the most important flexible electronics used in various electronic skin applications, including artificial intelligence, human-machine interfaces, health monitoring, and soft robotics. To obtain piezoresistive pressure sensors with improved sensitivity and reliability in sensing performance, we investigated the correlation between the pressure-sensing performance of the sensors and the nanostructures of the sensing media with controlled nanopatterned templates. To compare the effects of nanostructures on the pressure sensor performances, two nanorod-patterned sensing media with different nanoscales were used: one was a finely nanopatterned sensing medium, while the other was a relatively large nanopatterned medium using different anodized aluminum oxide (AAO) templates, named shAAO and bhAAO, respectively. The piezoresistive pressure sensor using the shAAO-replicated sensing medium exhibited better sensitivity, faster response/recovery rate, and better sensing reliability than the bhAAO-pressure sensor. This result suggests that optimizing the nanopatterned structures should be considered in terms of the interdigitated contact that proceeds between the two electrodes to obtain high-performance pressure sensors when designing nanopatterned sensing media applied through face-to-face assembly of the nanostructured substrate.