Shape-controlled synthesis and self-assembly of bismuth nanocrystals

Non-noble metal nanocrystals (NCs) have attracted considerable interest for wide applications, however, their development is constrained by the challenge of synthesizing high-quality nanostructures with precise control over their size and morphology. In this study, we present a shape-controlled synthesis of well-defined spherical and non-spherical bismuth (Bi) NCs through delicate control over reaction thermodynamics. Interestingly, the tunable fabrication of non-spherical Bi NCs (triangular nanoplates and nanorods) is successfully achieved by simply employing surfactants with different halide ions (Cl-and Br-), which selectively adsorb onto specific crystal facets during the growth process. Furthermore, these non-spherical Bi NCs can spontaneously self-assemble into two-dimensional (2D) and three-dimensional (3D) superlattices, where the stacking arrangement is dictated by both the geometry of the building blocks and the nature of the dispersion solvent. The successful synthesis of Bi NCs with diverse morphologies provides a robust platform for further exploration of structure-property relationships and potential applications.