Advances in the Colloidal Synthesis of Two-Dimensional Semiconductor Nanoribbons

The shape-controlled synthesis of colloidal semiconductor nanocrystals has attracted a lot of interest because of their shape-dependent physical and chemical properties. With the growing understanding of the shape evolution, several successful syntheses of two-dimensional (2D) nanocrystals have been reported. In this review, we focus on the recent advances in the colloidal synthesis of 2D CdSe nanoribbons with a wurtzite structure. 2D lamellar assemblies of CdSe clusters are generated in the early stage of the synthesis, and then they direct the formation of 2D structure. The dense organic layers on the {11 (2) over bar0} facets significantly stabilize the 2D nanoribbons. The nanoribbons exhibit unique optical properties originating from the strong ID quantum confinement within their extremely uniform and thin thickness. Interestingly, a large amount of manganese(II) ions can be incorporated into CdSe nanoribbons via a nucleation-controlled doping process. A high doping concentration and the strong confinement effect of the nanoribbons result in enhanced magneto-optical properties that are suitable for spintronic device applications. CdS nanoribbons have a very similar formation pathway, which suggests the cluster-assembled approaches can potentially be extended to various other materials.