Nanoparticle Formation by Laser Ablation and by Spark Discharges — Properties, Mechanisms, and Control Possibilities

Abstract

Laser ablation L" and spark discharge SD techniques are commonly used for nanoparticle NP formation. The produced NPs have found numerous applications in such areas as electronics, biomedicine, textile production, etc. Previous studies provide us information about the amount of NPs, their size distribution, and possible applications. On one hand, the main advantage of the L" method is in the possibilities of changing laser parameters and background conditions and to ablate materials with complicated stoichiometry. On the other hand, the major advantage of the SD technique is in the possibility of using several facilities in parallel to increase the yield of nanoparticles. To optimize these processes, we consider different stages involved and analyze the resulting plasma and nanoparticle NP parameters. "ased on the performed calculations, we analyze nanoparticle properties, such as mean size and mean density. The performed analysis shows how the experimental conditions are connected with the resulted nanoparticle characteristics in agreement with several previous experiments. Cylindrical plasma column expansion and return are shown to govern primary nanoparticle formation in spark discharge, whereas hemispherical shock describes quite well this process for nanosecond laser ablation at atmospheric pressure. In addition, spark discharge leads to the oscillations in plasma properties, whereas monotonous behavior is characteristic for nanosecond laser ablation. Despite the difference in plasma density and time evolutions calculated for both phenomena, after well-defined delays, similar critical nuclei have been shown to be formed by both techniques. This result is attributed to the fact that whereas larger evaporation rate is typical for nanosecond laser ablation, a mixture of vapor and background gas determines the supersaturation in the case of spark.

Quantum scale organic semiconductors for SERS detection of DNA methylation and gene expression

“…The "*" indicates the excited state of molecular species. The formation rate of each of the molecular species is determined by the individual bond energies 20 . Thus, the determination of molecular species, helps in regulating the functional groups present in the organic semiconductor probes.…”

Nanoparticles, Nanocrystals, and Nanocomposites Produced with Pulsed Laser Ablation and Their Applications

“…Although many synthesis and applications of nanoparticles have been demonstrated by using PLAL method in the past decade, the main physical mechanism behind PLAL method remains a puzzle. To understand the mechanism, Direct Simulation Monte Carlo (DSMC) calculations have been performed to simulate the ultra-short, laser-ablated plume dynamics and nanoparticle evolution under realistic experimental conditions [6].…”

Nanoparticle Generation by Double-Pulse Laser Ablation

“…Laser ablation (LA) is a unique tool for the fabrication of NPs, exhibiting several advantages over the classical wet chemical synthesis methods. On one hand, the main advantage of the LA technique is the possibility to preserve material stoichiometry during the ablation process [19]. On the other hand, LA is a faster and cleaner procedure since toxicity is difficult to avoid in traditional chemical routes of synthesis [20].…”

“…As a consequence, a certain degree of freedom for tailoring NPs size and composition is possible while the fabrication of complicated nano-objects is a difficult task, most of NPs being spherical. Recent advances in laser synthesis of NPs with both nanosecond and femtosecond pulses are reviewed in the book chapters published by Besner and Meunier [21], Voloshko and Itina [19], and Caricato et al [20]. Moreover, the processes involved in short pulse LA in vacuum and in a low pressure background gas, the generation of NPs and the deposition of NP-assembled films are discussed in Chapter 4 of this book.…”

“…A large description of the theoretical models currently used in simulations, with their advantages and limitations was reviewed (see e.g. [19,20,36,37] and references therein). An improvement of the theoretical approaches requires therefore reliable experimental data for comparison.…”