Enhancing the spectral selectivity of MgTiO3 via Mn doping for high temperature solar thermal conversion

Solar absorbers are vital for concentrated solar power (CSP) systems, yet spectral selectivity solar absorbers (SSAs) struggle with high-temperature stability in air. This study introduced Mn ions into MgTiO 3 (MTO) via a high temperature solid-phase synthesis technique to optimize the spectral selectivity. Unlike conventional doping that increased both absorptance and emittance, MgTi 0.4 Mn 0.6 O 3 (MTMO-0.6) boosted solar absorptance (α = 0.85) while maintaining low emittance (ε = 0.39, 1073.15 K) in the 2.5–15 μm wavelength range. Besides, the material retained high spectral selectivity (α/ε = 0.84/0.41) after heat treatment at 800 °C in air atmosphere for 90 h in total (9 h cycles −1 , 10 cycles), showing excellent thermal stability. Moreover, under concentrated solar irradiation of 10.83 W·cm −2 , MTMO-0.6 sample reached an equilibrium temperature of 848 ℃, surpassing that of MTO and SiC. The proposed Mn-doped MgTiO 3 has the potential as a solar absorber for high temperature solar thermal conversion.