Low-temperature fabrication of high-performance AZO/Ag/WO₃ multilayer films for flexible heaters

In this study, Al-doped ZnO/Ag/WO₃ (AZO/Ag/WO₃)multilayer films were fabricated on polyethylene terephthalate (PET) substrates using the magnetron sputtering technique. A two-step magnetron sputtering process was employed to deposit WO₃, effectively preventing insulation in the AZO/Ag/WO₃ multilayer film caused by silver oxidation. The optical properties of the AZO/Ag/WO₃ multilayer films can be adjusted by varying the thickness of AZO and WO₃ layers. The optimal AZO/Ag/WO₃ multilayer film demonstrates a maximum figure-of-merit of 1.74 × 10^− 2 Ω⁻¹, with an average visible light transmittance of 81.1% and a sheet resistance of 7.04 Ω sq^− 1. When applied in transparent flexible heaters, the AZO/Ag/WO₃ multilayer films exhibit rapid thermal response, stable and controllable heating performance at low operating voltage, indicating exceptional thermal properties and high conductivity. The two-step magnetron sputtering deposition of external oxide layers to prevent the oxidation of silver is cost-effective and can be utilized to create high-performance oxide/metal/oxide transparent electrodes.