Binary Surfactant-Mediated Tunable Nanotip Growth on Gold Nanoparticles and Applications in Photothermal Catalysis

Plasmon-Mediated Hydrogen Dissociation with Symmetry Tunability

The atomic-scale mechanism of plasmon-mediated H₂ dissociation on gold nanoclusters is investigated using time-dependent density functional theory. The position relationship between the nanocluster and H₂ has a strong influence on the reaction rate. When the hydrogen molecule is located in the interstitial center of the plasmonic dimer, the hot spot here has a great field enhancement, which can promote dissociation effectively. The change in the molecular position results in symmetry breaking, and the molecular dissociation is inhibited. For the asymmetric structure, direct charge transfer from the gold cluster to the antibonding state of the hydrogen molecule by plasmon decay makes a prominent contribution to the reaction. The results provide deep insights into the influence of structural symmetry on plasmon-assisted photocatalysis in the quantum regime.

Plasmonic Au-Cu nanostructures: Synthesis and applications

Plasmonic Au-Cu nanostructures composed of Au and Cu metals, have demonstrated advantages over their monolithic counterparts, which have recently attracted considerable attention. Au-Cu nanostructures are currently used in various research fields, including catalysis, light harvesting, optoelectronics, and biotechnologies. Herein, recent developments in Au-Cu nanostructures are summarized. The development of three types of Au-Cu nanostructures is reviewed, including alloys, core-shell structures, and Janus structures. Afterwards, we discuss the peculiar plasmonic properties of Au-Cu nanostructures as well as their potential applications. The excellent properties of Au-Cu nanostructures enable applications in catalysis, plasmon-enhanced spectroscopy, photothermal conversion and therapy. Lastly, we present our thoughts on the current status and future prospects of the Au-Cu nanostructures research field. This review is intended to contribute to the development of fabrication strategies and applications relating to Au-Cu nanostructures.

Twinned-Au-tip-induced growth of plasmonic Au-Cu Janus nanojellyfish in upconversion luminescence enhancement

The metallic Janus nanoparticle is an emerging plasmonic nanostructure that has attracted attention in the fields of materials science and nanophotonics. The instability of the Cu nanostructure leads to very complex nucleation and growth kinetics, and synthesis of Cu Janus nanoparticle has challenges. Here, we report a new method for synthesis of Au-Cu Janus nanojellyfish (JNF) by using twinned tips of Au nanoflower (NF) as seeds. The twinned nanotip of the Au NF and the large lattice mismatch between Au and Cu can induce formation of twin defects during the growth process, resulting in asymmetric deposition of Cu atoms. The symmetry-breaking using different sizes of Au NF and Cu nanodomains within the Au-Cu JNF can controllably change the localized surface plasmon resonance (LSPR) modes. The asymmetric Au-Cu JNF can induce plasmon coupling between dipolar and multipolar modes, which leads to clear electric-field enhancement in the near-infrared region. An Au-Cu JNF with multiple LSPR modes was chosen to simultaneously match the excitation and emission bands of the lanthanide-doped upconversion nanoparticles (UCNPs). A 5000-fold enhancement of the upconversion luminescence was achieved by using single plasmonic Au-Cu JNF. The Au-Cu JNF can also provide a guide for new metallic Janus nanoparticles in the fields of plasmonic, photothermal conversion, and nanomotors.