(Left) The multi-colored "KIST" letters made from the developed material were photographed with an optical camera and an infrared camera. The temperature of the letters is lower than the surrounding area. (Right) Measurement of the midday temperature change between the colored cooling material and commercial paint. Up to 30.8 oC lower temperature was achieved compared to commercial paint.

LC 242 liquid crystals and chiral dopants dispersed in an organic solvent are dripped onto a substrate and then applied thinly and widely using spin coating. After evaporation of the solvent, spiral liquid crystal photonic crystals are fabricated by UV curing.

Postdoctoral researcher Minjeong Kim (left) and principal investigator Jin Gu Kang (right) show the colorful radiative cooling material they created in the process lab.

A research team prepares to measure radiative cooling performance in the outdoor experimental space on the roof of the research building.