Smart tunable colorful thermal emitter based on In3SbTe2 for all-season thermal management

Improving thermal management is critical for boosting energy utilization efficiency. IST (In₃SbTe₂), a phase change material with non-volatile switching and wide modulability, enables dynamic thermal control. Herein, we introduce a five-layer thin-film modulatable thermal emitter based on IST, designed to integrate daytime solar heat collection and nighttime radiative cooling. The average absorptivity in the solar band (0.3–2.5 μm) reaches 0.8 in the amorphous state of this emitter, and the average emissivity at the atmospheric window (3–5 μm, 8–14 μm) is 0.23 and 0.13, respectively; in the crystalline state, the emissivity at the atmospheric window rises to 0.5 and 0.92, which enables the efficient realization of day and night thermal management. Adjusting ZnS thickness allows vivid, angle-stable coloration for architectural and camouflage uses. The emitter maintains stable emissivity under wide-angle incidence and varying refractive conditions, ensuring adaptability. Under AM1.5 illumination, it achieves over 80 % solar absorption with strong photothermal conversion, and net radiative cooling power reaches 70.37 W m⁻² at zero temperature difference. Adding a solar reflector reduces amorphous-state emissivity (0.19 at 3–5 μm, 0.22 at 8–14 μm) and crystalline-state solar absorptivity (0.3 at 0.3–2.5 μm), while increasing crystalline emissivity (0.55 at 3–5 μm, 0.89 at 8–14 μm), enabling daytime cooling and nighttime insulation. Finally, we performed simulations for typical application scenarios in reality and concluded that the proposed thermal emitter has good solar energy absorption, radiation cooling, and thermal insulation. In summary, the thermal emitter shows promising potential for efficiently utilizing and converting all-season energy.