Colloidal Plasmonic Titanium Nitride Nanoparticles: Properties and Applications

Abstract

Optical properties of colloidal plasmonic titanium nitride nanoparticles are examined with an eye on their photothermal and photocatalytic applications via transmission electron microscopy and optical transmittance measurements. Single crystal titanium nitride cubic nanoparticles with an average size of 50 nm, which was found to be the optimum size for cellular uptake with gold nanoparticles [1], exhibit plasmon resonance in the biological transparency window and demonstrate a high absorption efficiency. A self-passivating native oxide at the surface of the nanoparticles provides an additional degree of freedom for surface functionalization. The titanium oxide shell surrounding the plasmonic core can create new opportunities for photocatalytic applications. an excitement to develop technologies for a broad range of applications. The wide range of carrier concentrations available from several material classes spans the electromagnetic spectrum from the ultra-violet through the midinfrared [2]. Additionally, the broad variety of materials studied in the field provide extra degrees of freedom to solve technological challenges thanks to the unique properties such as tunability, process compatibility, chemical stability, etc [3]. KeywordsTransition metal nitrides, especially titanium nitride (TiN), have been studied for the last three decades due to the unique combination of their material properties [4]. Metallic behavior of TiN combined with its hardness and chemical stability has attracted attention in microelectronics research [5]. Adjustable optical properties and stoichiometry of TiN thin films were examined in the 1990s [6]. The optical characterization of TiN thin films was extensively performed later with the increasing interest in the field of plasmonics [7][8][9][10]. Improved properties with epitaxial TiN thin films have recently been demonstrated with a hyperbolic metamaterial and a plasmonic waveguide [11,12]. As a refractory plasmonic material, TiN holds the potential to solve critical issues associated with the softness and low melting points of plasmonic metals such as gold and silver [13,14]. In contrast to thin films, TiN nanoparticles have not been extensively studied until recently. Localized surface plasmons (LSPs) in TiN nanoparticles were first theoretically analyzed by Quinten [15], while their first experimental demonstration was performed by Reinholdt et al. [16] In their work, cubic nanoparticles smaller than 10 nm with a broad size dispersion were fabricated through laser ablation, and plasmon resonance peaks centered around 730 nm wavelength were reported. Reinholdt et al. proposed the use of TiN nanoparticles as inorganic, stable color pigments. We have previously shown that TiN nanoparticles provide field enhancement comparable to that achievable with Au, with a broader peak spectrally positioned in the biological transparency window [17]. In a more recent study, we experimentally analyzed the absorption efficiencies of lithographically fabricated TiN and Au nanoparticles an...

Solar-Powered Plasmon-Enhanced Heterogeneous Catalysis

“…We foresee an increased efficiency of one order of magnitude in the next years by using alternative plasmonic materials and by introducing proper engineering of the interfaces [100][101][102].…”

“…Over the last decade, the search for alternative plasmonic materials has gained momentum due to needs emerging with the technology transfer efforts [101,144,145]. Process compatibility, spectral match, chemical stability, cost reduction, and several other needs for specific applications forced the research direction into the investigation and optimization of a variety of material systems for plasmonic applications [102,[146][147][148]. Plasmonic photocatalysis can utilize alternative materials for efficient collection of broad solar spectrum.…”

“…Figure 7A shows the distribution of alternative materials over the electromagnetic spectrum where metals cover UV-visible range, plasmonic metal nitrides cover visible-near infrared, and semiconductors cover longer wavelengths in the NIR [140]. Due to optical properties similar to that of gold, metal nitrides such as ZrN and TiN ( Figure 7B) could be used to replace Au NPs in the vis-NIR region and to provide enhanced light harvesting and field concentration [101,102,[144][145][146][147]. Together with galliumdoped zinc oxide (GZO), showing plasmonic resonance in the 1400-2200 nm range [141], these alternative materials offer the possibility of covering a broadband spectrum to selectively activate chemical bonds.…”

The Sedimentation of Colloidal Nanoparticles in Solution and Its Study Using Quantitative Digital Photography

“…The use of a standard digital photo camera limits the applications to systems that have detectable optical response in the visible region. Many particle systems do indeed have such a response, for instance, plasmonic materials such as gold, silver, titanium nitride, but also other metal particles, semiconductor quantum dots, and paramagnetic iron oxide . Attainment of equilibrium can take quite some time, and an analytical photocentrifuge may be a time‐saving investment, which also will yield more precise analysis, in particular for broad size distributions and multimodal samples.…”

Band engineering of ternary metal nitride system Ti_1-x Zr_xN for plasmonic applications

“…To visualize the performance of these materials for different classes of plasmonic devices, we apply two quality factors defined for localized surface plasmon resonance (LSPR) and surface plasmon polariton (SPP) which are localized and propagating plasmonic oscillations at the surface of metallic components, respectively. Note that there are already some experimental demonstration on both LSPR [42,43] and SPP [44] with TiN. Their quality factors, QLSPR and QSPP, can be expressed in terms of their dielectric functional formulism as shown in Eqs.…”