Synergistic role of Cl− and Br− ions in growth control and mechanistic insights of high aspect ratio silver nanowires for flexible transparent conductive films

Abstract

Silver nanowires (AgNWs) with high aspect ratios are pivotal for the production of flexible transparent conductive films (TCFs). The growth of AgNWs is significantly influenced by the strong affinity of halogen ions for silver ions. This affinity plays a crucial role in the controlled deposition of silver along the nanowire axis. By precisely controlling the concentrations of Cl⁻ and Br⁻ ions, we have successfully synthesized AgNWs with remarkable lengths of 96 μm and diameters of 40 nm, achieving an impressive aspect ratio of 2400. Utilizing density functional theory and molecular dynamics simulations, we investigate the impact of these ions on the growth of AgNWs. Our findings reveal that halogen ions strongly adsorb onto the Ag (100) plane in the radial direction, with Cl⁻ ions promoting anisotropic growth and Br⁻ ions effectively limiting the nanowire diameter, thus achieving high aspect ratio AgNWs. The resulting TCFs exhibit a high transmittance of 95.0% at 550 nm and a low sheet resistance of 14.7 Ω sq⁻¹. Moreover, when integrated into a flexible transparent heater, these TCFs demonstrate a high heating rate of 12.1 °C s⁻¹. The development of AgNWs is poised to significantly enhance the performance and versatility of flexible TCFs.