Flexible tactile sensors based on silver nanowires: material synthesis, microstructuring, assembly, performance, and applications

Silver nanowires (AgNWs), with Ag possessing the highest inherent electrical conductivity among all the metal nanomaterials, have shown great promise as sensing elements of high-performance tactile sensors. This, along with their excellent flexibility due to their high aspect ratio, makes up an effective conductive network for flexible electronics. In recent years, flexible tactile sensors have received increased research attention due to their potential as electronic skin (E-skin) for healthcare monitoring, human motion detection, soft robotics, and so on. However, there is still a challenge in achieving good stability for AgNW-based sensors due to the mismatch of mechanical properties between AgNWs and stretchable polymer substrates. Different microstructure designs, device assembly, and material synthesis methods have been used to achieve AgNW-based sensors with excellent stretchability, stability, and sensitivity over a wide detecting range. This paper provides an overview of the various approaches in fabricating flexible tactile sensors based on AgNWs and their resulting performance. The relevant working principles and critical performance parameters are also briefly described. Lastly, the challenges and prospects in developing AgNW-based flexible sensors are highlighted.