Spectrally Selective Coatings for Energy Efficiency and Solar Applications

This paper gives a brief survey over some recent work on surface coatings for energy efficiency and solar applications. Specifically, it covers coatings for - selective absorption of solar energy (for solar collectors), - selective emission of infrared radiation in the 8-13 μm range (for passive cooling devices), - visible transmission combined with near-infrared reflectance (for windows with decreased inlet of solar energy), - solar transmission combined with thermal-infrared reflectance (for windows with decreased outlet of thermal radiation), - variable transmission of solar or visible radiation (for "smart windows" with dynamic control of radiant energy). One general conclusion from the survey is that the research field embodying these types of coatings remains, with a few exceptions, in a state of rapid progress.