Fabrication of silver nanowire-based stretchable electrodes using spray coating

• AgNW-based stretchable electrodes were fabricated using spray coating.
• A direct coating of AgNWs on uncured PDMS enhances the film quality.
• A stable resistance under strain was achieved by a bilayer electrode structure.
• The over-coated conductive layer suppresses the protrusion of AgNWs from PDMS.

We have fabricated silver nanowire (AgNW) films on polydimethylsiloxane (PDMS) substrates using a spray coater for the applications of a stretchable and transparent electrode. Inherently, they show poor surface roughness and weak adhesion to substrates. To tackle it, we have performed a direct spray coating of AgNWs on uncured PDMS in such a way that AgNWs penetrate into the uncured PDMS, thereby enhancing the surface morphology and adhesion properties of AgNW electrodes. However, the standalone AgNW films show an unstable resistance under tensile strain. We have therefore employed a conductive polymer, poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS), which is coated atop the AgNW film. Such a bilayer configuration ensures a stable resistance under strain because the over-coating layer of PEDOT:PSS effectively suppresses the protrusion of AgNWs from PDMS. It exhibits a moderate increase of sheet resistance (by a factor of ~ 2) with increasing tensile strain (up to 40%) and number of stretching cycles (up to 100 cycles).