Researchers in Japan have added impurities to layered perovskite ceramics that improve their reflectivity of near-infrared light, making them ideal for heat mitigation.
Layered perovskites such as titanium-added calcium manganese oxide ceramics have attracted attention as materials that can prevent solar heat absorption by reflecting near-infrared (NIR) radiation better than commercial pigments.
However, the mechanism underlying its high NIR reflectivity was not clear.
Researchers at the Nagoya Institute of Technology (NITech) have taken a combination of experimental and theoretical approaches to provide useful insights into the structure, properties and operation of these layered perovskites that can be extended to a wide range of crystalline ceramics.
The research could be used to combat the heat island effect. Urban areas without sufficient tree cover are significantly warmer than their surroundings.
This “urban heat island” effect results primarily from absorption of near-infrared (NIR) radiation in sunlight. NIR reflective pigments that can mitigate these heating effects are therefore highly desirable.
They can be used in construction or as a thermal coating for city buildings.
The principal investigator, Dr. Ryohei Oka, found that new perovskites such as titanium-added calcium manganese oxide ceramics (Ca2(Mn,Ti)O4) reflect NIR radiation much better than commercially available black pigments.
“These findings bring us closer to revealing the thermal shielding property of perovskite ceramics,” he said.
Nagoya Institute of Technology (NITech) is a respected engineering institute in Japan that was established in 1949.