Polyvinylpyrrolidone-Free Silver Nanowires for Alternating Current Electroluminescence Electrode Devices

Abstract

Silver nanowires (AgNWs) were prepared by the polyol method. The synthesis temperature was varied from 110 to 170 °C, with increments of 10 °C. At a low temperature of 110 °C, only a small amount of nanowires was formed. Many uniform and long nanowires were formed in a temperature range of 120–150 °C, but at high temperatures at 160 and 170 °C, the nanowires of larger diameter and shorter length were formed with some silver nanoparticles (AgNPs) on their surfaces. AgNWs under a reaction temperature of 140 °C (AgNWs-140 °C) exhibited the longest average length (88 ± 37 μ m) and the highest aspect ratio (1134 ± 485), with an average diameter of 77.2 ± 19.1 nm. These results indicate that 140 °C provides optimal growth conditions, achieving a balance between the nucleation and elongation processes. AgNWs-140 °C-based transparent conductive films (TCF) exhibited a low sheet resistance of 46 Ω/sq with the highest transmittance of 68% at a 550 nm wavelength. The assembled alternating current electroluminescence devices (AC-EL), having the device structure as a AgNWs-TCF/ZnS:Cu phosphor layer/BaTiO₃ dielectric layer/Ag-paste back-electrode, showed the luminance intensity depended on the sheet resistance and transmittance of the TCF film. The AgNWs-140 °C AC-EL device delivered the highest luminance of 531.1 ± 69.8 cd/m², which was about 95.4% of that of the standard conductive ITO/PEN TCF commercial electrode (557.6 ± 29.7 cd/m²).