Pair directed silver nano-lines by single-particle assembly in nanofibers for non-contact humidity sensors

Shape-controlled nano-silvers have great promise for the practical applications in devices due to their unique electronic properties. Although variously complicated nano-silver structures have been reported, the accurate control of one-dimension (1D) oriented assembly of Ag crystals remains challenging. Here, we innovatively fabricated Ag nano-lines (AgNLs) with pair directed arrays along the parallel boundary of the templated nanofibers. The multi-stage template mechanism of polyvinyl pyrrolidone (PVP) molecules based on electrospinning and UV irradiation played an indispensable effect in the coherent single-nanoparticle assembly of Ag nanocrystals in the nanofibers. Using the electrochemically assisted analysis, we found the special electron conduction and sensibility of water molecules in the AgNLs. Further, based on the tightly connected and gapped assembly characteristics of the AgNLs, we integrated the AgNLs arrays as the nanoscale humidity sensors which behaved the different sensing properties at low, middle and high relative humidity (RH). Our research demonstrated the application of AgNLs in the humidity-relative fields and provided a new strategy for fabricating the nanoscale 1D directed non-contact humidity sensors.