Copper cobaltate nanoneedles show 99.5% solar light absorption

Researchers at the University of the Basque Country (EHU) have developed ultra-black copper cobaltate nanoneedles capable of absorbing up to 99.5% of sunlight, surpassing the performance of the current standard vertically aligned carbon nanotubes, which absorb about 99%. These nanoneedles, especially when coated with zinc oxide, demonstrate superior thermal stability and optical absorption under the high-temperature and humid conditions typical of concentrated solar power (CSP) systems. This advancement could significantly enhance the efficiency and commercial viability of solar tower technology, which uses mirrors to concentrate sunlight onto a central tower to generate energy. The research, conducted by EHU’s Thermophysical Properties of Materials group, highlights the limitations of carbon nanotubes, which require protective coatings that reduce their effectiveness. In contrast, copper cobaltate nanoneedles maintain stability and higher absorption rates without such drawbacks. The findings have attracted international interest, including collaboration with the University of California San Diego and the U.S. Department of Energy