Corner-, edge-, and facet-controlled growth of nanocrystals

Abstract

The ability to precisely control nanocrystal (NC) shape and composition is useful in many fields, including catalysis and plasmonics. Seed-mediated strategies have proven effective for preparing a wide variety of structures, but a poor understanding of how to selectively grow corners, edges, and facets has limited the development of a general strategy to control structure evolution. Here, we report a universal synthetic strategy for directing the site-specific growth of anisotropic seeds to prepare a library of designer nanostructures. This strategy leverages nucleation energy barrier profiles and the chemical potential of the growth solution to control the site-specific growth of NCs into exotic shapes and compositions. This strategy can be used to not only control where growth occurs on anisotropic seeds but also control the exposed facets of the newly grown regions. NCs of many shapes are synthesized, including over 10 here-to-fore never reported NCs and, in principle, many others are possible.

Local Growth Mediated by Plasmonic Hot Carriers: Chirality from Achiral Nanocrystals Using Circularly Polarized Light

“… 65 Inhomogeneous growth can also be the consequence of distinct reaction probabilities on different sites, such as the flat nanostars depicted in Figure 1 c, whose final shape arises from the balance of electron and hole injection at different crystalline faces, 52 or can be controlled with the curvature of the edges in the NC geometry. 66 Also, it can arise from the larger excitation rates of hot carriers at plasmonic hot spots, producing growth patterns centered on these regions, such as the example in Figure 1 d showing the results of the galvanic reduction of silver triangular nanoprisms on excitation at their plasmonic resonance. 53 Importantly, the growth pattern can also reflect the symmetry of the incoming illumination, such as that shown in Figure 1 e, where the chiral deposition of PbO 2 over nonchiral Au rods is achieved by illuminating them with circularly polarized light (CPL).…”

Heterostructures Built through Site‐Selective Deposition on Anisotropic Plasmonic Metal Nanocrystals and Their Applications

“…Metals that have been selectively deposited on the specific sites of anisotropic plasmonic NCs include plasmonic metals (Cu, Ag, Au), [21,[46][47][48][49] catalytic metals (Ru, Pd, Pt), [18,44,45,[50][51][52][53] magnetic metals (Fe, Co, Ni), [54,55] and metal alloys such as AgPd, AgPt, and CoFe (Figure 2a-d). [46,49,[55][56][57][58] The deposited metal or alloy improves the plasmonic performance of the anisotropic plasmonic metal NC core or introduces additional functionality like catalytic activity and magnetism.…”

“…A very recent study has demonstrated that by appropriate ligands, distinct nucleation energy barriers for secondary nucleation (E) at the different sites can be introduced on anisotropic NC seeds and the chemical potential of the growth solution can be tailored, leading to site-selective deposition (Figure 4a,b). [48] For example, for a triangular Au nanoprism, the density of the ligand adsorbate varies at different sites with different curvatures. A higher curvature results in a larger average distance (δ) between the ligand molecules.…”

Cell Sheet‐Like Soft Nanoreactor Arrays

“…In contrast, synthetic chemistry is usually carried out in a bulk dilute solution, as is modern nanocrystal synthesis. In nanocrystal synthesis, soft organic materials, including small molecules, [ 1–4 ] polymers, [ 5–11 ] DNA, [ 12,13 ] and proteins, [ 14,15 ] have been widely used to regulate nanoscale nucleation/growth, enabling sophisticated control over the sizes and shapes of inorganic nanocrystals for various technical applications. Such organically guided inorganic crystallization has been carried out predominantly in bulk solutions.…”