One-step plasmonic welding and photolithographic patterning of silver nanowire network by UV-programable surface atom diffusion

Silver nanowire (AgNW) based transparent electrode (TE) plays a pivotal role in optoelectronics where TE is generally required to have fine pattern and high performance. Despite the rapid technological advances in either welding or patterning of AgNWs, there are few studies that combine the two processes in a simple and practical manner. Here, aiming to fabricate high-performance patterned AgNW TE, we develop a simplified photolithography that enables both plasmonic nanowelding with low-level UV exposure (20 mW/cm²) and high-resolution micropatterning without photoresist and etching process by conjugating AgNW with diphenyliodonium nitrate (DPIN) and UV-curable cellulose. The cellulose as a binder can effectively enhance plasmonic heating, adhesion, and stability, while the photosensitive DPIN, capable of modulating surface atom diffusion, can boost the plasmonic welding at AgNW junction and induce patterning in AgNW network with Plateau-Rayleigh instability. The fabricated AgNW TE has high figure of merit of up to 1, 000 (3.7 Ω/sq at 90% transmittance) and minimal pattern size down to 3 µm, along with superior robustness. Finally, a flexible smart window with high performance is demonstrated using the patterned and welded AgNW TEs, verifying the applicability of the simplified photolithography technique to optoelectronic devices.