Surface Plasmon Resonance-Induced Diffusion-Limited Aggregation in the Formation of Ag/AgOx Nanonetworks as Broad-Spectrum Transparent Conductors

Abstract

Based on the generation and transportation of hot electrons and the diffusion-limited aggregation of Ag+ ions induced by the surface plasmon resonance of surface Ag nanoparticles (NPs) with ambient moisture, we develop a new mechanism for fabricating a surface Ag nanonetwork (NNW) structure on a slightly conductive template through Ag NP reorganization and AgOx formation. Such an extended NNW structure consists of distributed Ag NPs covered and connected by AgOx to form a highly transparent conductive network. Its sheet resistance is as low as ∼140 Ω/square while its transmittance lies between 80 and 90%. The process of diffusion-limited aggregation is regulated by electrostatic induction between diffuse Ag+ ions in a thin surface water layer condensed from moisture and the sharp tips of an NNW structure during its formation. Oxygen atoms can be dissociated from AgOx when a post-thermal treatment at a temperature higher than 412 °C is applied, leaving behind an Ag thin layer, which still connects the remaining Ag NPs to form a different conductive network of ∼240 Ω/square in sheet resistance. Such an NNW structure can stand an elevated temperature up to ∼400 °C and is thermally stable. It can extend the transparent spectrum into ultraviolet and near-infrared ranges and can be applied to touch-panel displays, ultraviolet light-emitting diodes, and flexible optoelectronics devices.