Optical Property Change of Silver Nanowire Thin Films in Laser Patterning Process

Abstract

Silver nanowire thin films are attractive materials for flexible electrodes as an alternative for conventional tin-doped indium oxide films. An appropriate patterning process is required to apply nanowire-based transparent electrodes into the optoelectronic devices. In this paper, we report the optical property change in silver nanowire transparent electrodes during laser ablation process. We discovered that, when silver nanowires were patterned by nanosecond pulsed lasers at infrared wavelength, their optical properties were changed. The change of optical properties was caused by nanoresidues remaining on the surface. It was analyzed that the color and transparency of thin films were changed because the residual nanoparticles absorbed the visible light wavelengths where silver nanoparticles possess their peak values in the absorption spectra. The nanoparticles were derived from insufficient vaporization of silver nanowires during infrared laser ablation. In the case of using an excimer laser for patterning, the nanoparticles were not left more on the surface due to complete removal of silver nanowires, since silver has higher absorption coefficient at the wavelength of excimer laser. As a result, high-quality patterning of silver nanowire thin films could be obtained without any deterioration of optical properties in transparent electrodes.