Core/shell copper nanowire networks for transparent thin film heaters

摘要

Copper nanowires (Cu NWs) appear as the strongest alternative to silver nanowires (Ag NWs) in transparent conductors. Cu NWs; however, are more prone to oxidation compared to Ag NWs even at room temperature. This problem becomes more severe when Cu NWs are used as transparent thin film heaters (TTFHs). In this work, we have utilized ALD deposited zinc oxide (ZnO) shell layers, and provide a comparison with typically used aluminum oxide (Al2O3) shell layers to improve the TTFH performance. While Cu NW network TTFHs barely withstood temperatures around 100 degrees C, critical thickness of ALD deposited Al2O3 and ZnO layers were determined to find out TTFH limits. Maximum stable and reproducible temperatures of 273 degrees C and 204 degrees C were obtained for Al2O3 and ZnO deposited Cu NW network TTFHs, respectively. An extensive parametric study on the NW density and oxide type in conjunction with the electrical conductivity and optical transmittance was conducted. A remarkably high heating rate of 14 degrees C s(-1) was obtained from the fabricated core/shell networks with improved oxidation stability under ambient and high humidity conditions. Finally, these high performance core/shell Cu NW network TTFHs were utilized as efficient defrosters.