Direct coating of gold nanolayers to enhance the oxidation resistance of copper nanowire flexible transparent conductive films

Abstract

Copper nanowire-based transparent conductive films have garnered extensive attention owing to their cost-effectiveness and comparable electrical properties. However, the inherent instability of copper nanowires (Cu NWs) has curtailed their extensive utility and applicability. Herein, we present durable Cu@Au NW/PET films exhibiting elevated photoelectric attributes and remarkable flexibility. After preparing Cu NWs, the purification operation allows the purity of the Cu NWs to reach about 98%. Subsequently, Cu@Au NWs/PET flexible transparent conductive films (FTCFs) were prepared through vacuum filtration of Cu NWs and direct treatment with chloroauric acid. The resulting Cu@Au NW-based FTCFs exhibit impressive attributes including a low sheet resistance of 30 ohms per square and a high optical transmittance of 90%, resulting in an exceptional figure of merit (FOM) of 99. Remarkably, the Cu@Au NWs/PET film showed remarkable flexibility, retaining its properties after 10 000 cycles of continuous bending. Stability assessments further affirm the sheet resistance of the Cu@Au NW FTCFs remains nearly unchanged over 75 days at ambient temperature. The strategic integration of a gold nanolayer, serving as a protective coating on the Cu NWs, yields substantial enhancements in both electrical conductivity and overall stability within the Cu NW FTCF architecture. Furthermore, the obtained Cu@Au NW films exhibit rapid heating capabilities, reaching a temperature of 67 °C within 30 seconds at 3.5 V and subsequently returning to room temperature at the same rate. In summary, the introduction of a Au protective layer can effectively enhance the oxidation resistance of Cu NWs, which has great application potential in FTCFs in the field of film heaters.