Low haze transparent electrodes and highly conducting air dried films with ultra-long silver nanowires synthesized by one-step polyol method

Transparent electrodes made of silver nanowires (AgNWs) exhibit higher flexibility when compared to those made of tin doped indium oxide (ITO) and are expected to be applied in plastic electronics. However, these transparent electrodes composed of AgNWs show high haze because the wires cause strong light scattering in the visible range. Reduction of the wire diameter has been proposed as a way to weaken light scattering, although there have seldom been any studies focusing on the haze because of the difficulty involved in controlling the wire diameter. In this report, we show that the haze can be easily reduced by increasing the length of AgNWs with a large diameter. Ultra-long (u-long) AgNWs with lengths in the range of 20-100 mu m and a maximum length of 230 mu m have been successfully synthesized by adjusting the reaction temperature and the stirring speed of a one-step polyol process. Compared to typical AgNWs (with diameter and length of 70 nm and 10 mu m, respectively) and ITO, a transparent electrode consisting of u-long AgNWs 91 nm in diameter demonstrated a low haze of 3.4%-1.6% and a low sheet resistance of 24-109 Omega/sq. at a transmittance of 94%-97%. Even when fabricated at room temperature without any post-treatment, the electrodes composed of u-long AgNWs achieved a sheet resistance of 19 Omega/sq. at a transmittance of 80%, which is six orders of magnitude lower than that of typical AgNWs.