Researchers have developed a simple, low-cost, and environmentally sound method for fabricating a highly-efficient selective solar absorber (SSA) to convert sunlight into heat for energy-related applications. The team used a 'dip and dry' approach whereby strips coated with a reactive metal are dipped into a solution containing ions of a less reactive metal to create plasmonic-nanoparticle-coated foils that perform as well or better than existing SSAs, regardless of the sun's angle.