LAUSR

The size and shape of nanocrystals determine their material properties. Research into how this interaction plays out in semiconductor nanocrystals has mainly focused on materials containing heavy metals, such as cadmium chalcogenide nanocrystals. These can be toxic and lead to concerns about environmental impacts, so chemists are working to synthesize heavy-metal-free “green” semiconductor nanostructures. To that end, Uri Banin, Anatoly I. Frenkel, and co-workers have developed a protocol for producing ZnSe nanostructures with controllable shapes and sizes using well-defined molecular clusters (DOI: 10.1021/jacs.8b05941). The researchers first synthesized ZnSe clusters stabilized with oleylamine ligands. By heating the reaction solution containing these clusters, they generated ZnSe nanowires of 2.4 nm diameter and a few hundred nanometers in length. Adding small amounts of additional zinc clusters disrupted the nanowire growth, leading to significantly shorter nanowires. Increasing the amount of zinc clusters further broke up the nanowires, leading to ZnSe nanorods, and eventually nanodots. The researchers show the ability to expand this technique by replacing the zinc clusters with copper-based clusters to produce Cu-doped nanostructures. This technique opens up new paths for producing controlled semiconductor nanostructures free of heavy metals. Christen Brownlee