Ultrastable silver nanoparticles could provide cheaper alternative to gold

Nature : Although more expensive than silver, gold nanoparticles have been preferred because gold is stabler and easier to handle. Now, however, two teams of researchers have independently developed methods to create silver nanoparticles that are more robust. Terry Bigioni of the University of Toledo in Ohio and coworkers have created a nanoparticle that contains 44 silver atoms—12 form a hollow icosahedron at the core, 20 form a dodecahedron around the core, and the remaining 12 bond to sulfur-containing molecules to form a cage around the rest. A similar nanoparticle, also with 44 silver atoms, has been developed by a team led by Nanfeng Zheng of Xiamen University in China. Zheng’s group also came up with a mixed silver–gold particle, which is stabler than the pure silver one. The new nanoparticles can be produced cheaply and reliably produced and absorb light better than gold does. Such noble-metal nanoparticles have many uses, including in photochemistry, optoelectronics, and biomedicine.