Solar Selective Coatings: Industrial State-of-the-Art

Solar selective absorber materials have been the focus of much research and development over the last 60 years as the functionality of solar thermal collection devices relies considerably on these coatings and their operation and deposition specifications are complex. This article reviews the solar selective absorber coatings which have been patented and covers a wide variety of materials and techniques including metal/ceramic composites (cermets), semiconductors, paint coatings, electroplating and vapour deposition processes. The cermet class of materials has emerged as the most utilised with the recent selective coatings based on nanoscale particulates. As the operating temperatures in solar devices increases so demands on reliability, thermal stability and durability continue to grow. Furthermore, there is pressure to reduce costs and the advances in nanoscale technologies and thin film deposition seem to offer the greatest potential for new selective coatings.