Size Modification of Optically Active Contamination‐Free Silicon Nanoparticles with Paramagnetic Defects by Their Fast Synthesis and Dissolution

Abstract

Contamination-free silicon-based nanoparticles (NPs) with several modalities are developed in this work. They are formed by non-toxic laser-assisted decomposition of silicon microgranules homogeneously dispersed in deionized water. Precise control of numerous experimental parameters allows repeatable fine tuning of nanoparticle size solving significant lacks of a direct laser ablation routine. Such a method provokes a huge amount of paramagnetic defect states of optically active silicon NPs that can serve as a contrast agent for magnetic resonance and nonlinear optical imaging. Perspectives of their bioapplication are driven by detected their fast size degradation in a NaCl-based medium.

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

“…The small (10 nm) and large (100 nm) composite NPs may reveal different structure and chemical composition. For instance, small NPs may combine nanocristalline and amorphous phases of Si (responsible for Raman and EPR signals [31], respectively) with nanocristalline gold. Performed calculation of interatomic distances in a small NP (Fig.…”

“…Particularly promising are silicon nanoparticles (Si NPs) prepared by means of pulsed laser ablation in liquid, revealing several aspects important for biomedical applications [12,[30][31][32][33][34][35].…”

Environmentally Friendly Improvement of Plasmonic Nanostructure Functionality towards Magnetic Resonance Applications

“…Both types of Au-based NPs have clear plasmonic maxima ( Figure 7 a) while the observed 18 nm blue shift of the plasmonic maximum of AuSi NHs can be associated with lower mean size of NPs. Their higher absorbance in the shorter wavelength range can indirectly indicate the presence of nanostructured silicon having a similar absorbance value [ 33 ]. Another direct evidence of the presence of silicon content in the synthesized nanomaterial follows from the EDX data giving us its quantitative value for nanoparticles of different sizes ( Figure 4 b).…”

“…To improve the functionality of plasmonic nanoparticles, we employed the PLAL technique by irradiation of a gold target (purity of 99.999%) in deionized water-based environment with 30 nm spherical Si NPs whose concentration was varied in the range of 0–70 mg/L ( Figure 1 ) [ 33 ]. Bare Au NPs were obtained by PLAL without Si NPs while the presence of Si NPs in water led to the formation of hybrid nanostructures.…”

“…To overcome the above-mentioned issues and ensure a high chemical purity of hybrids, preparation of nanomaterials is performed in biocompatible gaseous or liquid environments by using “green” laser-based methods. In particular, pulsed laser ablation in liquids (PLAL) has proven to be a very effective tool of the production of single-element plasmonic [ 28 , 29 , 30 ] and semiconductor silicon-based [ 31 , 32 , 33 , 34 , 35 ] nanoparticles with tuneable properties. Moreover, the efficient production of bimetallic nanostructures was achieved by laser-induced merging of plasmonic and magnetically active elements [ 36 , 37 , 38 , 39 , 40 ].…”