Shaped femtosecond laser induced photoreduction for highly controllable Au nanoparticles based on localized field enhancement and their SERS applications

Abstract

Gold nanoparticles (Au NPs) have a wide range of applications because of their localized surface plasmon resonance properties. Femtosecond laser is considered to be an effective method for preparing Au NPs because of its characteristics of ultrashort irradiation periods and ultrahigh intensities. In this study, a novel method is proposed to produce an Au NP-attached substrate using the spatially and temporally shaped femtosecond laser. Laser-induced periodic surface structures (LIPSS) are designed to obtain the localized optical field enhancement, which leads to the femtosecond laser spatially reshaping, enabling the deposition of Au NPs by photoreduction on silicon substrates. The Au NPs prepared by this method exhibit morphological controllability and chemical stability, especially excellent spatial selectivity and uniformity, resulting in the tunable and stable surface-enhanced Raman scattering (SERS) applications. Also, the temporally shaped femtosecond pulses are introduced to further increase the enhancement factors of the SERS. This method successfully achieves the controllable morphology synthesis and selective deposition of Au NPs on the substrate simultaneously, which provides a promising candidate for SERS substrates fabrication, and holds potential applications in optoelectronics, such as molecular detection and biosensors.

Laser-Induced Deposition of Plasmonic Ag and Pt Nanoparticles, and Periodic Arrays

“…Laserinduced forward transfer (LIFT) achieves the spatially controlled formation of a donor Materials 2021, 14, 10 2 of 14 material (that can be a metal film as well) on a receiving substrate [7]. As a hybrid method of surface functionalization with metal NPs, preliminary surface activation with femtosecond laser beam, followed by laser induced photoreduction, can be mentioned [8].…”

Classification of Preeclamptic Placental Extracellular Vesicles Using Femtosecond Laser-fabricated Nanoplasmonic Sensors and Machine Learning

“…In contrast, femtosecond (fs) laser ablation offers a scalable, tunable, single step, and reproducible approach to SERS substrate fabrication. [34][35][36][37][38] Many efforts have been focused on exploiting fs-laser machining to tune surface wettability, creating combinations of superhydrophobic/philic areas that enhance detection performance by concentrating analyte molecules into hotspot areas, leading to the detection of concentrations down to 10 −13 M using SERS. [39][40][41][42] Additionally, fs-laser induced plasma assisted ablation has been used to create active SERS substrates based on Ag nanoparticles, demonstrating promising results regarding food safety detection.…”

Biomedical Applications of Metal 3D Printing

“…There is an experimental DED technique that uses an arc plasma as an integrating agent, known as plasma-arc directed energy deposition (DED-PA), but it produces large structures with low precision, resolution, and surface quality (19); instead, μPS uses a low-current glow discharge for finer process control. Because μPS does not use binder, it creates imprints with near-bulk electrical conductivity without annealing (∼85% bulk value for gold), surpassing competing technologies such as electrohydrodynamic deposition (jetting of metal micro/nanoparticle solutions using high electric fields; see 106-108), laser-assisted electrophoretic deposition (creation of deposits via electrophoresis of metal micro-and nanoparticles confined by high-intensity photons; see 109), laser-induced forward transfer (direct transfer by laser ablation of materials sourced as a thin film on a transparent substrate; see 110, 111), meniscus-confined electroplating (see 112,113), laser-induced photoreduction (photochemical reduction of metal salt solutions using a rastering laser; see [114][115][116], and focused-ion-beam-induced deposition (deposition of metallic molecules from the ion-induced dissociation of gases; see 117, 118) (Table 2). In principle, many materials can be sputtered, but the reported μPS work focuses on gold and copper (see [99][100][101][102][103][104].…”