Nanoscale Electronic-Structural Synergy Induced by Sr Doping Enables Record-Low Room-Temperature Infrared Emissivity in SmCoO3-Based Perovskites

• • Record-low infrared emissivity of 0.12 in the 8–14 μm band at room temperature achieved in Sr-doped SmCoO3 (x=0.3), surpassing conventional coatings (typically >0.5) and enabling superior thermal stealth performance. • • Sr doping induces Co3+/Co4+ mixed valence and oxygen vacancies, increasing carrier concentration to 3.5×10^21 cm^-3 and electrical conductivity to 1.2×10^3 S/cm, which are critical for high infrared reflectivity. • • First-principles calculations show bandgap narrowing from 1.8 eV to 0.9 eV upon doping, enhancing double-exchange interaction and carrier transport, providing a mechanistic basis for the emissivity reduction. • • The material retains emissivity below 0.15 after 100 h thermal cycling at 300°C and 500 h damp heat (85°C/85% RH), demonstrating robust environmental stability essential for real-world infrared stealth applications.