Gold nanoparticles boost solar efficiency by capturing full spectrum

A research team from Korea University has developed a novel gold nanoparticle material called "supraballs" that significantly enhances solar energy absorption by capturing nearly the entire solar spectrum. Unlike traditional gold or silver nanoparticles, which primarily absorb visible wavelengths and thus only a fraction of sunlight, these supraballs are self-assembled clusters of gold nanoparticles optimized in size to absorb a broader range of wavelengths. When applied as a coating on a commercial thermoelectric generator (TEG), the supraballs nearly doubled solar absorption compared to conventional gold nanoparticle films, achieving about 89 percent absorption versus 45 percent. The team used computer simulations to design and optimize the supraballs for maximum sunlight absorption, predicting over 90 percent efficiency, which was then validated through real-world testing under ambient conditions without specialized equipment. This coating technology offers a simple and cost-effective method to improve solar-thermal and photothermal systems, potentially lowering barriers to high-efficiency solar energy harvesting in practical applications. The study detailing these findings