Silver nanowire-network-film-coated soft substrates with wrinkled surfaces for use as stretchable surface enhanced Raman scattering sensors

Abstract

We demonstrate silver nanowire -network-film (AgNWNF)-coated soft polydimethyl siloxane (PDMS) substrates with wrinkled surfaces for use as stretchable SERS sensors. The AgNWNF-coated stretchable substrates showed strong SERS effects compared to those of Ag film-deposited substrates, which were likely attributed to the electromagnetic field enhancement induced by the relatively high density of hot spots in the AgNWNF. To investigate the stability of the stretchable SERS sensors, we examined the adhesion strength of AgNWNEs on the ultraviolet-ozone (UVO)-treated PDMS substrates, which was much stronger than the adhesion strength of AgNWNFs on the PDMS without prior UVO treatment. In addition, the strain-dependent SERS activity of the AgNWNF-coated stretchable sensor showed the detection of 10(-7) M Rhodamine 6G (R6G) molecules despite the decreased Raman intensity under strain increased to 100%, resulting from the surface plasmon resonance tuning by the modulation of the active gap distance between neighboring AgNWs through the application of strain. This was further supported by finite-difference time domain (FDTD) numerical evaluation. (C) 2020 Elsevier B.V. All rights reserved.