Fabrication of transparent conductors that are mechanically stretchable is challenging yet essential in developing soft electronic devices such as stretchable displays. Until now, indium tin oxide (ITO) has been the most commonly used transparent electrode materials. However, ITO cannot endure tensile strains as an oxide material. Therefore, investigations of novel transparent electrodes in curvilinear stretchable devices have been growing. Ag nanowire (Ag NW) networks are considered one of the strong candidates for stretchable transparent conductors due to their superior transparency and conductivity. Most previous studies have been focusing only on uniaxially stretchable conductors and very few studies have been attempted to create electrodes that are stable under biaxial mechanical deformations.<br/><br/>Here we present Ag NW-based transparent conductors that are biaxially stretchable. We have developed a facile method to control the structure of nanowire networks in an isotropic manner that releases applied strains so that the nanowires sustain the conductive nanowire network. Strain tests and cyclic tests showed that samples prepared by our method have high strain tolerance regardless of the direction of stretching while electrodes prepared via prestraining method have strain tolerance only in the direction of a prestrained direction. Scanning electron microscope (SEM) was utilized to analyze the cause of improved electrical stability under biaxial stretching in our developed electrodes. Prepared Ag NW networks were directly applied to a dielectric elastomer actuator as compliant electrodes. As the actuator repeatedly expands and contracts isotropically under applied voltages, it requires compliant electrodes to be also stretchable in all directions. Results showed superior cyclic stability and greater expansion for actuators utilizing our biaxially stretchable electrodes. We anticipate our findings could potentially be applied to other metal nanowires for stretchable optoelectronic applications.

Biaxially stretchable Ag NW-based transparent conductors

250th National Meeting (2015)

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