Enhanced stretchability and stability of micro hole mesh electrodes via a crack-guiding notch design

Abstract

The rapid development of flexible devices demands higher stretchability and stability in conductive metal electrodes, which are indispensable components in a wide range of flexible technologies. In this work, we propose and demonstrate a novel hole mesh structure featuring a directional crack-guiding notch (CGN) design, which can help to disperse stretching stress/strain, while effectively confining cracks to pre-notched locations, minimizing harm to the structural continuity and electrical conductivity of the electrode film. As a proof of concept, hole mesh thin films (Pt/Au) with the CGN design were fabricated and transferred directly onto the elastic polymer substrate (polydimethylsiloxane, PDMS) and tested under repetitive stretching. It is found that the hole mesh electrodes, with CGN design, demonstrate significantly enhanced stretchability and excellent stability of conductivity, withstanding up to 20% strain for 170 cycles—a remarkable improvement compared to the reference samples without notches, which typically fail at lower strains. Further finite element simulations further reveal that the crack-guiding notches effectively suppress uncontrolled crack propagation through the whole mesh electrode, releasing accumulated strain only at the predefined notched locations in a well-controlled manner, and thus maintaining the overall conductivity of the hole mesh electrodes. This very convenient but effective CGN design holds great promise for broad applications in stretchable electronics, sensors, and displays.