Extremely Robust and Reliable Transparent Silver Nanowire‐Mesh Electrode with Multifunctional Optoelectronic Performance through Selective Laser Nanowelding for Flexible Smart Devices

Abstract

As the demand for foldable or rollable smart electronic devices increases, the issue of damage caused by cyclic fatigue of the flexible transparent electrode (FTE) due to repeated bending stress at extremely low bending radius is emerging. Herein, it is demonstrated that a mesh electrode composed of silver nanowires (Ag NW–mesh) with multifunctional optoelectronic performance microfabricated without photomasking via selective laser nanowelding (SLNW) followed by soft‐etching of highly ductile Ag NWs on a flexible polymer film exhibits long‐term cycling stability at bending stresses of a 1 mm radius of curvature (ROC). In the optimal NW microgrid pattern design, the cycle fatigue resistance of NW–mesh electrodes considerably increases with increase in NW areal mass density (AMD) and decreasing microgrid spacing due to the improved weldability and networkability of NWs at a low laser energy density of 1 J cm−2. A diagonally gridded NW–mesh electrode with 30 μm line spacing exhibits extremely high reliability with little change in the performance of Joule heating and electromagnetic interference shielding under long‐term bending stresses of 300 000 cycles at 1 mm ROC. Being a simple process without photomasking, this method can easily use a multifunctional FTE with ultrahigh fatigue resistance and reliability suitable for highly flexible smart devices.