Colloidal Control of Branching in Metal Chalcogenide Semiconductor Nanostructures.

Colloidal syntheses of metal chalcogenides yield nanostructures of various 1D, 2D, and 3D nanocrystals (NCs), including branched nanostructures (BNSs) of nanoflowers, tetrapods, octopods, nanourchins, and more. Efforts are continuously being made to understand the branching mechanism in colloidally prepared metal chalcogenides for tailor-making them into various morphologies for dedicated applications in solar cells, light-emitting diodes, stress sensor devices, and near-infrared photodetectors. The vital role of precursors and ligands has widely been recognized in directing nanocrystal morphology during the colloidal synthesis of metal chalcogenide nanostructures. Moreover, a few basic branching mechanisms in nanocrystals have also been derived from decades-long observations of branching in NCs. This Perspective (a) accounts for the mediation of branching in In 2 S 3 , PbS, MoSe 2 , WSe 2, and WS 2 ; (b) analyzes the underlying mechanisms; and (c) gives a future perspective toward better controlling the BNSs' morphologies and their impact on applications.