Bilayer-stabilized Pt/HfO₂ films for long-term low infrared emissivity with exceptional thermal durability

Maintaining ultralow infrared emissivity under high-temperature service conditions requires exceptional structural stability in thin-film materials. However, conventional noble metal films often suffer from severe solid-state dewetting at high temperatures, which inevitably disrupts their conductive networks and leads to the failure of infrared performance. Herein, we developed a highly thermally stable Pt/HfO₂ bilayer film, in which the top HfO₂ layer with minimal infrared interference acts as a robust barrier to suppress the upward migration and agglomeration of Pt atoms. This physical structural design effectively preserves the continuous Pt network and promotes lateral coarsening of Pt grains during the heating process, thereby minimizing electron scattering to achieve ultralow infrared emissivity. Consequently, even after 150 h of heat treatment at 1000 °C, the Pt/HfO₂ bilayer film maintains low emissivities of 0.188 and 0.136 in the 3–5 μm and 8–14 μm bands, respectively. Furthermore, it demonstrates an outstanding thermal radiation suppression effect by drastically reducing the apparent radiation temperature to a mere 189.0 °C against a 1000 °C background. This work establishes a reliable structural design for long-term thermal radiation suppression in demanding high-temperature applications.