Plasmonic Core–Shell Zirconium Nitride–Silicon Oxynitride Nanoparticles

Abstract

We discuss the synthesis and properties of plasmonic zirconium nitride nanocrystals produced using a nonthermal plasma reactor. The process enables the continuous conversion of chemical precursors into free-standing ∼10 nm diameter nanoparticles. Oxidation limits the resonant plasmon energy from ∼2.6 eV for ideal unoxidized particles to ∼2.1 eV for particles exposed to air at room temperature. A simple modification to the plasma process allows the inflight growth of a conformal silicon oxynitride shell onto the zirconium nitride core. The shell inhibits the oxidation of the core, resulting in particles with a plasmon energy of 2.35 eV. These particles show good plasmonic behavior even after annealing in air at 300 °C, largely improved when compared to unprotected particles that oxidize and lose plasmonic activity at the same temperature. This work represents a step toward the development of earth-abundant, thermally and chemically resistant nanoparticles that can offer an inexpensive alternative to gold and silver and extended applicability in harsh environments.

Overview of Synthetic Methods to Prepare Plasmonic Transition‐Metal Nitride Nanoparticles

“…Shells composed of SiO 2 or SiO x N y have been shown to narrow and intensifyt he LSPRs in TiNa nd ZrN, respectively. [43,48] Such strategies could be expanded to other TMNs as well. Molecular ligands have not been explored on plasmonic nitride NPs yet and can provide another pathway to prevents urfaceo xidation andr ender desired solubility and functionality.A dditionally,m ost of the synthetic methods described herein yieldeds pherically shaped NPs.…”

“…Nonthermal plasma synthesis was used to preparef reestanding plasmonic ZrN NPs. [48] ZrCl 4 wasr eacted with NH 3 to yield ac rystallinep roduct at ap roduction rate of about 20 mg h À1 .T EM analysiss howed the particles to be spherically shaped, with an average size of 8.2 nm ( Figure 5D). The extinction spectrum of ZrNN Ps showed the LSPR maximum at 585 nm ( Figure 5E).…”

“…[47].Copyright 2018, American Chemical Society.D)TEM image of bare ZrN NPs preparedb yu sing the nonthermal plasma method,E )experimentala nd F) calculated extinction spectrao fb are and silicono xynitride coated ZrN NPs, and G) electronm icroscopy-energy-dispersive X-ray mapping of silicon oxynitride coated ZrN NPs, showing the elementalcomposition.R eproduced with permission from ref. [48].C opyright2 019, American Chemical Society. face oxidation, ZrN NPs werec oated with about 2nma morphous silicon oxynitride shells through the plasma method ( Figure 5G).…”

Nanocrystal‐based inorganic nanocomposites: A new paradigm for plasma‐produced optoelectronic thin films

“…One such example of dual functionalities would be the combination of an electrically conductive nanocrystal network, for example, of ZnO nanocrystals with a matrix phase that exhibits plasmonic absorption. Group 4 transition metal nitrides have interesting plasmonic properties [ 60–64 ] and are amenable to ALD. For plasmonic applications, a nanocrystalline matrix is preferable to an amorphous one.…”

Synthesis, plasmonic properties, and CWA simulant decontamination activity of first row early transition metal nitride powders and nanomaterials

“…Some early transition metal nitrides, particularly TiN and ZrN, have optical properties similar to noble metals (e.g., Au, Ag), making them potential drop-in replacements for these expensive and, in some cases, chemically unstable materials. In fact, TiN has been shown to exhibit plasmonic resonances similar to those of Au but at a far reduced cost and with much greater thermal stability [1][2][3][4][5][6][7]. Additionally, there is already a fair body of literature that already describes the use of hot charge carriers, generated via plasmon decay [8], to perform a number of reactions [9], including water oxidation [10,11], water reduction [12][13][14], oxidation of amines to aldehydes [15], CO 2 reduction [16], and NH 3 decomposition [17].…”