Improvement in Conductivity and Mechanical Stability\nof a AgNW-Based Transparent Conductive Film by Using Ag Ionic Ink

Transparent\nconductive films (TCFs) based on silver nanowires (AgNWs)\nhave become popular in flexible electronics. However, the high junction\nresistance between AgNWs and the poor attaching stability of AgNWs\nto the substrate greatly hinder their industrial application. In this\nstudy, a welding strategy is proposed to address these two major challenges\nsimultaneously encountered with AgNW-based TCFs. This is achieved\nby trapping a thermally reducible silver ionic ink into gaps of the\nAgNW-based TCF and following low-temperature as well as intense pulse\nlight (IPL) treatment. During the curing process, the ink decomposes\ninto metallic silver to weld the wire junction and adjacent wire ends,\nthus improving the conductivity of the TCF significantly. More importantly,\nthe subsequent IPL treatment would endow the decomposed Ag with excellent\nadhesion to the poly(ethylene terephthalate) (PET) substrate through\nmechanical locking and chemical interaction effects. Therefore, the\nmechanical stability of the TCF is fundamentally enhanced through\nrobust connection between AgNWs and the substrate via the metallic\nsilver. After being welded using ionic ink, the conductivity of AgNW-based\nTCFs is enhanced by up to 58% with negligible changes in transparency.\nMoreover, the welded TCFs exhibit good stability compared with an\nas-coated AgNW-based TCF even after undergoing rigorous tests, including\n10,000 bending cycles and 100 tape peeling tests. Finally, such a\nstrategy is successfully applied to enhance the properties of a flexible\ntransparent heater, verifying its feasibility in flexible electronics.