Solution processed glass/fluorine-doped tin oxide/aluminum-doped zinc oxide double layer thin films for transparent heater and near-infrared reflecting applications

Double layer glass/fluorine-doped tin oxide (FTO)/aluminum-doped zinc oxide (AZO) multifunctional thin films were achieved via ultrasonic spray pyrolysis (USP) method without employing a post-deposition annealing. Transparent heater and near-infrared heat reflection behaviors were investigated. The samples were characterized in terms of their structural, morphological, optical, and electrical properties. The top AZO layer exhibited a polycrystalline structure without any preferred orientation. The double layer structure showed very high average transmittance (87%, 400-700 nm) in the visible and reflectance (55%, 2500 nm) in the near-infrared, regions. In addition, the sheet resistance and resistivity of the film were measured as 14.85 (Omega sq(-1)) and 1.78 x 10(-3) (Omega cm), respectively. The saturation temperature, response time, surface temperature uniformity, areal power density, and thermal resistance values were found to be 111 degrees C, 174 s, 11.42%, 0.299 W/cm(2), and 282.8 degrees C cm(2) W-1 for a sample with an active area of 31.5 cm(2) and input voltage of 9 V. In addition, dry-ice cooled samples (-25 degrees C) showed impressive deicing performance depending on the input power. In case of 12 V, all ice was defrosted, and water droplets were evaporated within 2 min and 10 s. During this process, a heating rate of similar to 43 degrees C/min was achieved.