Ag-Decorated Si Microspheres Produced by Laser Ablation in Liquid: All-in-One Temperature-Feedback SERS-Based Platform for Nanosensing

Abstract

Combination of dissimilar materials such as noble metals and common semiconductors within unified nanomaterials holds promise for optoelectronics, catalysis and optical sensing. Meanwhile, difficulty of obtaining such hybrid nanomaterials using common lithography-based techniques stimulates an active search for advanced, inexpensive, and straightforward fabrication methods. Here, we report one-pot one-step synthesis of Ag-decorated Si microspheres via nanosecond laser ablation of monocrystalline silicon in isopropanol containing AgNO3. Laser ablation of bulk silicon creates the suspension of the Si microspheres that host further preferential growth of Ag nanoclusters on their surface upon thermal-induced decomposition of AgNO3 species by subsequently incident laser pulses. The amount of the AgNO3 in the working solution controls the density, morphology, and arrangement of the Ag nanoclusters allowing them to achieve strong and uniform decoration of the Si microsphere surface. Such unique morphology makes Ag-decorated Si microspheres promising for molecular identification based on the surface-enhanced Raman scattering (SERS) effect. In particular, the designed single-particles sensing platform was shown to offer temperature-feedback modality as well as SERS signal enhancement up to 106, allowing reliable detection of the adsorbed molecules and tracing their plasmon-driven catalytic transformations. Considering the ability to control the decoration degree of Si microspheres by Ag nanoclusters via amount of the AgNO3, the developed one-pot easy-to-implement PLAL synthesis holds promise for gram-scale production of high-quality hybrid nanomaterial for various nanophotonics and sensing applications.

Single-step fabrication of hybrid germanium-gold/silver nanoentities by femtosecond laser ablation and applications in SERS-based sensing

“…The generated CB contains both ionized species of the target (Ge) and surrounding material (AgNO 3 /HAuCl 4 ) [46][47][48][49]. Owing to the pressure gradient, the CB expands rapidly into the surrounding liquid, followed by collapse leading to the formation of alloy (Ge-Ag) NPs [19,36,50]. Subsequently, the vaporized material fragments re-solidify on the surface of the Ge target over time.…”

“…Gurbatov et al [36] have studied the fabrication of hybrid Ag-Si microspheresvia ns ablation of Si in AgNO 3 (5 × 10 -4 M). Further, hybrid Ag-Si substrates were employed to detect 10 −6 M concentration of R6G through the SERS approach.…”

Single-Step Fabrication of Resonant Silicon–Gold Hybrid Nanoparticles for Efficient Optical Heating and Nanothermometry in Cells

“…Meanwhile, as the Si particles were produced into the liquid upon laser ablation, these particles further acted as local light absorbers and nanoheaters that give surface sites for preferential growth of the Au nanoclusters. 28,29 Additionally, Au NPs formed in the solution volume upon laser irradiation also attached to the surface of pure Si or Si−Au NPs. 13,30 The geometry of the obtained hybrid nanostructures (Si−Au NPs) was investigated with TEM, and the elemental mapping confirmed the presence of Si NPs (50−250 nm) with attached Au NPs (1−15 nm; Figures 4B,C and S11).…”

Accurate prediction of the optical properties of nanoalloys with both plasmonic and magnetic elements

“…In nanoparticles (NPs) and nanostructures, conduction electrons can be excited also by electromagnetic radiation, leading to surface plasmons and localized surface plasmons (LSP) 1 , 2 . Over the last decades, plasmonics permeated a wide range of sectors with critical importance for future technological challenges, such as sensing 3 , 4 , photocatalysis 5 – 7 , sunlight conversion 8 , metamaterials 9 , nanomedicine 10 , nonlinear 11 and quantum 12 , 13 optics. Each of these applications has specific requirements that cannot be simultaneously fulfilled by a single material 14 – 16 .…”