Scattering force and heating effect in laser-induced plasmonic welding of silver nanowire junctions

Light-nanomaterial interaction is accompanied by a scattering force and a heating effect. When silver nanowires are irradiated by a laser pulse with light intensity above the melting threshold, they are observed to melt into nanospheres and fly away from their original position. Simulation and experimental results show that the localized surface plasmon resonance excited by laser pulse will heat the ends and junction areas of silver nanowires, causing the occurrence of local melting at these locations. Since the local melting cannot alter the position of silver nanowire, a mathematical model was developed to evaluate the scattering force acting on silver nanowire. According to the developed mathematical model, the scattering force acting on silver nanowire mainly depends on specific surface area of silver nanowire and incident light intensity. When the light intensity of the laser pulse is ${3.0} \times {{10}^{12}}\;{\rm W}/{{\rm m}^2}$3.0×10¹²W/m², the scattering force acting on the silver nanowire can reach ${{10}^5}$10⁵ times the gravity of silver nanowire. To obtain silver nanowires networks, the light intensity of the laser pulse was manipulated to regulate the scattering force and heating effect acting on the silver nanowire. As a result, silver nanowire networks were obtained with light intensity of ${1.4} \times {{10}^{10}}\;{\rm W}/{{\rm m}^2}$1.4×10¹⁰W/m² at a scanning speed of 1000 mm/s. This laser-induced plasmonic welding paves the way for improved understanding and control of fundamental laser-nanomaterial interactions.