Enhancing overall performances of Cu/Ag/AZO multilayer films for transparent heaters via laser/furnace step-by-step annealing mode

Four different step-by-step annealing modes based on furnace and/or laser annealing (i.e. F + L, F + F, L + F and L + L) were developed and compared with one-step furnace or laser annealing mode (i.e. F and L), with an aim to enhance overall performances of Cu/Ag/AZO (CAA) multilayer films applied to transparent heaters. It was found that the L + F step-by-step annealing mode improved the transmittance and conductivity of the CAA film to the greatest extent, and therefore the resulting sample L + F achieved the best overall performance with a figure of merit of 4.26 × 10−2 Ω−1. These results should be ascribed to that laser annealing for the AZO layer in the first step facilitated growth and recrystallization of AZO grains to provide better nucleation sites for overlying Ag and Cu grains, and furnace annealing of the whole CAA film in the second step promoted the melting of the surface Ag and Cu grains to re-aggregate with the nearby AZO grains. The transparent heater prepared from the sample L + F exhibited a high steady-state temperature of 127.1 °C within a short response time of 80 s under an input voltage of 3 V, as well as good heating stability and effective deicing function.