Near- to Long-Wave-Infrared Mercury Chalcogenide Nanocrystals from Liquid Mercury

HgTe nanocrystals are currently the most promising colloidal material for infrared detection, combining broadly tunable infrared absorption and photoconductive properties. Current syntheses lead to a limited amount of material and rely on a highly toxic water-soluble form of Hg. Here, we explore the possibility of using Hg thiolate as Hg source and demonstrate that the latter can be formed in situ from liquid Hg. The developed protocol allows large masses (7 g) and highly concentrated (100 g/L) syntheses, which is a step forward for the transfer of this material toward industry. The transport properties of the material have also been investigated, and we observe a transition from p- to n-type with size. We observe that the threshold of the p-to-n switch depends on the growth method, which enables a given size of nanocrystal to form a p–n junction. This work has great potential for the design of infrared sensors with optimized charge dissociation.