Expedient paramagnetic properties of surfactant-free plasmonic silicon-based nanoparticles

Abstract

Surfactant-free multifunctional semiconductor-metallic nanostructures possessing several modalities are formed due to laser-induced structural modification of pure silicon nanoparticles in the presence of gold. It results to variable size-dependent chemical composition examined by energy-dispersive X-ray spectroscopy. Laser-synthesized silicon-based nanocomposites exhibit remarkable both plasmonic and paramagnetic properties. Their plasmonic maxima are found to be easily adjusted in the whole visible spectral range. Influence of resonant laser irradiation on spin behaviour of silicon-gold nanoparticles is established. Their spin-lattice and spin-spin relaxation processes are investigated as well. Such multifunctional nanoparticles can reveal a huge potential for different applications in field of nanomedicine, in particular, for biosensing and bioimaging.

Merging of Bi-Modality of Ultrafast Laser Processing: Heating of Si/Au Nanocomposite Solutions with Controlled Chemical Content

“…here d is the size of the Si nanostructures and E g is their optical bandgap values. However, this suggestion contradicts to the observed size decrease in Si/Au NCs (Figure 2b) [20,42].…”

“…But in this case, narrowing of the Si bandgap corresponds to increasing the size of the nanostructures according to the following formula [ 40 , 41 ]: here d is the size of the Si nanostructures and E g is their optical bandgap values. However, this suggestion contradicts to the observed size decrease in Si/Au NCs ( Figure 2 b) [ 20 , 42 ]. Another reason for the bandgap modification can be associated with the formation of the shallow/deep donor/acceptor electronic states in the semiconductor bandgap playing a role of charge carrier traps.…”

“Green” Fluorescent–Plasmonic Carbon-Based Nanocomposites with Controlled Performance for Mild Laser Hyperthermia

“…Aiming to reveal the plasmonic properties of the laser-synthesised nanocomposites, their absorbance spectra were measured in the visible spectral range (280-800 nm). In all cases, apart from the carbon absorption band at 350 nm, laser ablation led to the appearance of plasmonic features either at around 400 nm (for silver) or 520 nm (for gold) (Figure 3), thus allowing us to vary the spectral position of the plasmonic maximum [17]. Moreover, their intensity also considerably depended on the duration of the laser treatment.…”

“…In particular, platforms based on silicon and plasmonic metals, such as Ag-Si or Au-Si prepared via pulsed laser ablation, have been reported recently for optical sensing and light-to-heat conversion applications [13,14]. Furthermore, Si-Au nanocomposites can also be formed without the use of any chemical surfactants via laser ablation of a metallic target immersed in colloidal solutions of semiconductor nanoparticles that were also prepared by PLALs [15][16][17][18][19].…”

Multi-Modal Laser-Fabricated Nanocomposites with Non-Invasive Tracking Modality and Tuned Plasmonic Properties

“…In order to overcome the above-mentioned issues, an environmentally friendly "green" synthesis method based on ultrafast laser irradiation is widely used for the formation of singleelement or bi-metallic nanostructures [28][29][30][31][32][33]. Recently, the possibility of manufacturing nanostructures by combining semiconductor and metallic elements in one nanoparticle was demonstrated [34][35][36][37][38]. Nevertheless, this field of laser-matter interaction, which is promising for biomedical applications, is still under development, providing the novelty of the research.…”