Optical properties of silver nanowire/polymer composite films: absorption, scattering, and color difference

Abstract

In transparent conductive electrodes using silver nanowire (AgNW) networks, regions with and without AgNWs exhibit different optical properties. This phenomenon, known as “pattern visibility,” is typically undesirable. In this study, the intrinsic optical properties – absorption, scattering and extinction – of AgNW/polymer composite films are derived from transmission and reflection spectra measured using an integrating sphere. These spectra reveal two major properties of AgNWs: transverse mode extinction due to localized surface plasmon resonance in the near-ultraviolet region, and longitudinal mode extinction in the visible to near-infrared region. By comparing AgNW/polymer composite films with similar sheet resistance, we find that composite films with smaller AgNW diameters show large absorption in the near-ultraviolet region, but limited scattering over the entire wavelength region, despite large amounts of AgNWs. We also show that pattern visibility is reduced for composite films with smaller AgNW diameters, which exhibit a smaller color difference ΔE 00 (CIEDE2000) between the regions with and without AgNWs, when applied to the diffuse reflection spectra.