Color‐Tunable Glass for Adaptable Thermal Management Based on Silver Phase Change

Abstract In recent years, passive thermal management systems have emerged as an essential energy‐saving strategy to mitigate carbon emissions. However, traditional heat management approaches, such as photothermal devices and radiative coolers, often face application limitations due to their complex construction, aesthetic constraints, and inability to adapt to diverse architectural requirements. This study proposes a colored thermal engineering glass fabricated through a simple annealing process, where Ag nanoparticles are formed on a TiO 2 film and an Ag layer. The structure of Ag layers can be easily controlled by adjusting the annealing temperature, allowing for systematic tuning of the optical efficiencies in the visible and long‐wave infrared regions. Consequently, thermal management devices can selectively function as either a photothermal heater or a radiative cooler, depending on the morphology of Ag layers. In particular, the photothermal device can function as an anti‐fogging solution for structural designs without requiring external energy. Furthermore, the stacked metal‐insulator‐metal structure induces plasmonic resonance phenomena, producing visible colors that range from vivid to dull hues. The tunable color variations enhance the suitability of the thermal management device for a wide range of architectural applications.