Realization of Tunable Localized Surface Plasmon Resonance of Cu@Cu₂O Core–Shell Nanoparticles by the Pulse Laser Deposition Method

Abstract

Cu@Cu2O core–shell nanoparticles (NPs) not only possess a stabilized structure but also exhibit better photocatalytic performance as compared to pure Cu2O. Therefore, preparation of Cu@Cu2O core–shell NPs is key toward efficient photocatalysis applications. In this paper, the fabrication of Cu@Cu2O core–shell NPs on single-crystal MgO(100) substrates has been studied systematically by pulse laser deposition. Scanning electron microscopy (SEM) images show that the average diameter of NPs is enlarged from 89.9 to 150.3 nm with the increasing of oxygen pressure. Transmission electron microscopy (TEM) images indicate that the NPs have elongated hexagons and a core–shell structure with a shell thickness of about 10 nm. UV–vis absorption spectra show that the position of the localized surface plasmon resonance (LSPR) peaks shifts from 648 to 858 nm and the full width at half-maximum (fwhm) of the LSPR peaks broadens from 226.7 to 436.5 nm with increasing average diameter of NPs. According to the analysis, the red shift of the LSPR peaks is caused by enlargement of the core diameter; higher fwhm is a result of broadened particle size distribution and the elongated morphology of NPs. Therefore, the width and range of LSPR peaks of the absorption spectrum can be tuned using this method, which is beneficial for enhancing the light absorption and improving the photocatalytic efficiency of Cu@Cu2O core–shell NPs.

Copper‐Based Plasmonic Catalysis: Recent Advances and Future Perspectives

“…), metal‐organic frameworks (MOFs), and graphene. [ 137,141–143,144–146 ] Taking Cu@TiO 2 core‐shell heterostructures derived from the Cu‐MOF for solar‐driven hydrogen evolution reaction (HER) as an example, Cu NPs are encapsulated by highly amorphous TiO 2 , which effectively inhibits the oxidation of Cu NPs (Figure 5D,E). [ 137 ] Meanwhile, Schottky barrier at the interfacial contacts between Cu NPs and TiO 2 promoted the fast photoexcited charge separation, contributing to the enhancement of hydrogen production rate.…”

Laser-Induced Deposition of Plasmonic Ag and Pt Nanoparticles, and Periodic Arrays

“…Metal nanoparticles (NPs) are a particular class of objects that are of interest due to their plasmonic properties and that can be synthesized with laser technologies. Among the most widespread techniques of metal NPs synthesis, are pulsed laser ablation/deposition in vacuum, gas, or liquid phases [1][2][3], as well as direct synthesis under intense laser beam focused in a solutions of metal salts [4,5]. These methods demonstrate high processing efficiency and a wide list of metal NPs have been synthesized with controlled parameters.…”

Morphology and Optical Properties of Gas-Phase-Synthesized Plasmonic Nanoparticles: Cu and Cu/MgO

“…This analysis is of crucial importance for the design of new functional materials. Different physical synthesis procedures have been developed in recent years: top-down methods, such as e-beam lithography [18,19] and focused ion beam assisted deposition [20], and bottom-up methods, such as pulsed laser deposition [21] thermal evaporation with self-organization [22][23][24][25][26], and gas-phase synthesis [6,[27][28][29]. The last method has been proved to be very flexible, because of the possibility of selecting the NP mass, generating nanoalloys [30], and developing core-shell geometries [31], which are of crucial importance if the protection of NPs from contamination is needed.…”

“…The main problem with the use of Cu NPs is their instability during air exposure, with consequent oxidation and loss of the localized surface plasmon resonance (LSPR). A possible solution is the generation of a stable oxide shell (mainly composed of Cu (II) oxide), with ozonization [36] or thermal treatment [21]. An alternative one-step procedure is the co-deposition of the pre-formed NPs with an inert and transparent material that can act either as a matrix or as a shell.…”

“…Ag/MgO NPs produced in this way were also deposited on the porous TiO 2 layer of perovskite solar cells, giving rise to an increase in PCE by 5% [15]. Although Cu NPs/MgO systems have been previously studied, MgO has mainly been used as an inert substrate [3,21,34,35] In this study, Cu NPs and Cu/MgO NPs were generated with a magnetron-assisted gas aggregation source (GAS), and they were co-deposited with MgO by making use of reactive thermal evaporation of Mg in O 2 . The chosen substrates were Si with its native oxide (Si/SiO x ), highly oriented pyrolytic graphite (HOPG), and quartz.…”