Infrared, transient thermal, and electrical properties of silver nanowire thin films for transparent heaters and energy-efficient coatings

In this study, we investigate the infrared and electrical properties as well as the thermal response of transparent silver nanowire (AgNW) based thin-film heaters, when subjected to Joule heating. Controlling the number of layers and hence the deposition time, our spray-coating technique allows to modulate the thermal and electrical properties of the thin films in a precise manner. In addition, this technique enables the fabrication of homogeneous and large-area heaters, which, in terms of their electro-optical properties, nicely compare to the performances of state-of-the-art AgNW transparent electrodes. The thermal response and the electrical properties are accurately reproduced by a purposely developed physical model, which shows that the temperature dependence of the AgNW film resistance is lowered by a factor of 2 compared to bulk silver, independently of the number of deposited layers. Compared to uncoated glass, the emissivity decreases by 58% at a coverage rate of 58%. At the same time, the AgNW film can sustain a transparency as high as 81.3%. Therefore, AgNW-based thin films can be used as a low-emissivity coating, for e.g., energy-efficient window glazing applications. Finally, we accurately determine the fragmentation temperature of AgNWs, which sets the ultimate limitation of use for heating applications.