Length-dependent electro-optical properties of silver nanowires-based transparent conducting films

In this paper, silver nanowires (AgNWs) with mean diameters of 65 nm and mean length of 9.8 µm were synthesized by the polyol solvothermal method. Sonication-induced scission was used to obtain AgNWs with a length range of 7.1–3.3 µm, and further AgNWs solutions were prepared with as-synthesized AgNWs as conductive fillers in the ethanol. A series of AgNWs random networks were prepared on the glass substrate using spray coating technique. Photoelectric properties and microstructure characterizations of AgNWs random networks were conducted to identify changes in such properties and the extent of these changes as a function of the length and content of AgNWs. The results show the sheet resistance and the transmittance of AgNWs network gradually increase as the length of AgNWs decrease. However, as the concentration of AgNWs increase, the sheet resistance and the transmittance of AgNWs networks decreases and increases, respectively. To obtain an approximative Rs of AgNWs film, the concentration of AgNWs with a length of 7.1 µm should be 1.2 times that of AgNWs with a length of 9.1 µm, with a 10% dropped transmittance. These results are attributed to the increase of the contact resistance among AgNWs networks and the density of AgNWs at the same area coverage. As the concentration of AgNWs increases, the deposition density of AgNWs networks increases, and both the sheet resistance and the transmittance decrease gradually.