Low-cost PDRC colored paint coatings, which reduce glare and increase the color diversity of PDRC surfaces, have also been developed. While some of the surface's solar reflectance is lost in the visible light spectrum, colored PDRCs can still exhibit significant cooling power, such as a coating by Zhai et al., which used a α- Bi 2 O 3 coating (resembling the color of the compound) to develop a non-toxic paint that demonstrated a solar reflectance of 99% and heat emissivity of 97%.