Stretchable Transparent Electrode via Wettability Self-Assembly in Mechanically Induced Self-Cracking

Stretchable and transparent electrodes (STEs) are indispensable components in numerous emerging applications such as optoelectrical devices and wearable devices used in health monitoring, human-machine interaction, and artificial intelligence. However, STEs have limitations in conductivity, robustness, and transmittance owing to the exposure of the substrate and fatigue deformation of nanomaterials under strain. In this study, an STE consisting of conductive materials embedded in in situ self-cracking strain-spread channels by wettability self-assembly is fabricated. Finite element analysis is used to simulate the crevice growth using the representative unit cell network and strain deformation using a random network. The embedded conductive materials are partly protected by the strain-opening crevice channel, and network dissociation is avoided under stretching, showing a maximum strain of 125%, a transmittance of approximately 89.66% (excluding the substrate) with a square resistance of 9.8 Ω sq-1, and high stability in an environment with high temperature and moisture. The wettability self-assembly coating process is verified and expanded to several kinds of hydrophilic inks and hydrophobic coating materials. The fabricated STE can be employed as a strain sensor in motion sensing, vital sign and posture feedback, and mimicking bioelectronic spiderweb with spatial gravity induction.