Advanced NIR-Reflective Taupe Pigments from 3d-metal-doped SrTiO3 Ceramic Systems

Abstract

Conventional inorganic pigments used in building materials typically absorb significant amounts of near-infrared (NIR) radiation, leading to heat buildup, increased energy consumption, and exacerbation of the urban heat island effect. As a result, there is growing interest in developing new pigments that combine attractive color with high NIR reflectivity. This study investigates the development of NIR-reflective perovskite pigments based on uncoloured SrTiO3. 3d elements such as Mn, Fe, Co and Ni were successfully incorporated into the perovskite structure of SrTiO3 at a substitution rate 0.05 (1 % at.). At such low content, doping induced distinctive taupe hues, indicating significant visible light absorption while maintaining high NIR reflectivity. Furthermore, the NIR reflectivity of the pigments was enhanced by reducing particle size through mechanical treatment. The perovskite pigments exhibited high NIR reflectance, with values ranging from 45 % to 77 %, underscoring their potential for reducing heat absorption in energy-efficient coatings.