Perovskite Oxide Solar Absorber with 94% Solar Absorptance and Stability to 1300 °C

Abstract We present a perovskite oxide solar thermal absorber material with a solar absorptance exceeding 0.935 ± 0.01 and stability to 1300 °C in both air and steam environments. The material is based on doped lanthanum manganite La0.8Ca0.2Mn0.8Al0.2O3 pigment, obtained via facile sol–gel synthesis, and subsequently prepared into a paintable paste-like coating amenable to a range of application techniques including brush, doctor blade, and spray deposition. The material exhibits strong broadband absorption across the ultraviolet–visible–near-infrared (UV–Vis–NIR) range, with a peak spectral absorptance up to 0.950 at a wavelength of 0.6 μm, which closely aligns with the peak in the solar spectrum. Cycling in ultrahigh-temperature conditions using a purpose-built cycling furnace revealed the noteworthy stability of the material, with a reduction in solar absorptance of just 0.2% after five consecutive 12 h cycles at 1300 °C followed by a 100 h hold. This work introduces perovskite oxides as ultrahigh temperature photothermal absorber materials, positioning them as promising materials to enable the next generation of ultrahigh temperature solar thermal systems.