Cooperation of Hot Holes and Surface Adsorbates in Plasmon-Driven Anisotropic Growth of Gold Nanostars

Abstract

Light-driven synthesis of plasmonic metal nanostructures has garnered broad scientific interests. Although it has been widely accepted that surface plasmon resonance (SPR)-generated energetic electrons play an essential role in this photochemical process, the exact function of plasmon-generated hot holes in regulating the morphology of nanostructures has not been fully explored. Herein, we discover that those hot holes work with surface adsorbates collectively to control the anisotropic growth of gold (Au) nanostructures. Specifically, it is found that hot holes stabilized by surface adsorbed iodide enable the site-selective oxidative etching of Au0, which leads to nonuniform growths along different lateral directions to form six-pointed Au nanostars. Our studies establish a molecular-level understanding of the mechanism behind the plasmon-driven synthesis of Au nanostars and illustrate the importance of cooperation between charge carriers and surface adsorbates in regulating the morphology evolution of plasmonic nanostructures.

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

“… 64 It is worth noting, however, that carrier-mediated growth can also develop with homogeneous patterns, especially when it depends on bulk-type interband transitions. 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.…”

“…(c) Plasmon-driven anisotropic growth of Au nanostructures: SEM image of the resulting geometry, with a 100 nm scale bar, and inset showing a diagram with initial and final morphologies. 52 (d) Diagram and TEM image of a silver nanoprism after growth through galvanic replacement at its corners on illumination at its main plasmonic resonance by unpolarized light. 53 (e) TEM images of Au@PbO 2 chiral structures successfully photogrown by using circularly polarized illumination over nonchiral Au rods.…”

“… 54 (f) Schematic depiction of the development of chirality from a nonchiral NC by using HE-mediated photogrowth under circulary polarized light (CPL). (c) was reproduced with permission from ref ( 52 ). Copyright 2020 American Chemical Society.…”

Photoinduced Electron and Energy Transfer Pathways and Photocatalytic Mechanisms in Hybrid Plasmonic Photocatalysis

“…[ 7 ] A wide range of redox reactions has been shown to be driven by d‐band holes generated by the interband damping of LSPs in Au nanoparticles. Some prominent examples include light‐driven nanoparticle growth, [ 157,158 ] Fe 3+ reduction, [ 159–163 ] and CO 2 reduction. [ 164–167 ] As one recent example, Kamarudheen et al.…”

Highly Porous Au–Pt Bimetallic Urchin-Like Nanocrystals for Efficient Electrochemical Methanol Oxidation

“…The Noble metals are active and stable materials that can be applied to various electrocatalysis [1][2][3][4][5]. Recently, noble metal-based nanocrystals (NCs) have been widely studied owing to their unique physical and chemical properties, which are different from those of their parent metals in bulk [6][7][8][9]. In particular, Pt-based NCs have been extensively investigated as a potential candidate material for various electrochemical reactions including electrochemical fuel oxidation, oxygen reduction, sensing, and hydrogen evolution by water splitting [10][11][12][13][14].…”