Transparent conductive AZO/Cu mesh/AZO composite films and their electrothermal performance

To address the trade-off between optical transmittance and electrical conductivity in transparent conductive films, we systematically fabricated a series of AZO and Cu mesh composite films on quartz substrates at room temperature by photolithography and magnetron sputtering. Evaluations of different architectures and mesh geometries revealed that the sandwiched AZO/Cu mesh/AZO structure delivers the optimal optoelectronic performance, achieving a figure of merit four orders of magnitude higher than single-layer AZO. Parameter optimization showed that reducing the mesh linewidth to 10 μm and side length to 100 μm increases metal coverage, effectively minimizing sheet resistance. The optimized multilayer film demonstrated a low sheet resistance of 15.45 Ω sq−1 and an average visible transmittance of 85.63%. When configured as a transparent heater, the device exhibited a rapid thermal response, stabilizing at 49.7 °C within 100 s under a 5 V DC bias. Furthermore, protected by the top AZO layer, the composite film maintained excellent long-term stability, showing negligible resistance variations after 90 days of exposure to both room temperature and 60 °C environments.