Review on experimental and theoretical investigations of the early stage, femtoseconds to microseconds processes during laser ablation in liquid-phase for the synthesis of colloidal nanoparticles

Abstract

Laser ablation in liquid-phase (LAL) has been developed since the 1990s, but the interest in laser synthesis of colloids has emerged in the last decade due to a significant improvement in the production rate, proven comparative advantages in biomedical and catalysis applications, and recent commercialization. However, the method relies on highly transient phenomena, so that the fundamental understanding lacks behind the LAL synthesis refinement research. The complexity of the physics and chemistry involved has led to experimental and theoretical investigations that attempt to provide a basic description of the underlying processes but face the challenge of temporal and spatial resolution as well as non-equilibrium conditions. It appears that the processes occurring at the early time scales, ranging from femtoseconds to several microseconds are critical in the definition of the final product. The review is mainly dedicated to the comprehensive description of the processes occurring at early time scales, which include the description of laser-matter interaction for ultrashort and short laser pulses, plasma formation processes as well as comparison of the measured plasma parameters at these time scales, and subsequent description of the cavitation bubble dynamics. Furthermore, the plasma and cavitation bubble chemistry are addressed, and their impact on the nanoparticle formation is emphasized.

Composition and structure of magnetic high-temperature-phase, stable Fe–Au core–shell nanoparticles with zero-valent bcc Fe core

“…The formation of segregated NPs in LAL is based on the minimization of interface and surface energy by a thermodynamic driving force, which was also veried by Amram et al 16,17 On the other hand, non-equilibrium steps such as the initial steps of LAL with unparalleled cooling rates could yield metastable particle structures not thermodynamically favored at room temperature. 3,18 Recently, we identied that a Fe-rich target composition and a NP diameter above 10 nm are decisive for the formation of CS NPs. 12 Furthermore, the CS yield could be increased up to 99% in mass, by utilization of nanosecond pulses and thin layered targets.…”

Synthesis of silicon nanoparticles by laser ablation at low fluences in water and ethanol

“…The crystallization mechanism of the semiconductor nanocrystals involves extreme thermodynamic conditions occurring during the ablation process [11]. Irradiation with high energy nanosecond pulses of a target produces the melting and evaporation of the surface, leading to a plasma expansion into the liquid, the pressure and temperature produced in the process are high enough to modify the structure of the particles; also, thermal quenching plays and important role on the crystalline structure of the obtained silicon nanocrystals [4,12]. Figure 5 shows the Raman spectra of the laser irradiated colloidal Si in water.…”

“…The laser treated nanoparticles are bigger than the non-treated. According to the literature, this means that laser melting (LM) was induced instead of laser fragmentation [11,12]. However, in the sample irradiated for 5 min there is a laser fragmentation since the crystals reduced their size from 4 to 3 nm.…”

“…LFL aims at downsizing particles from micro and nanometer sizes into smaller ones. While LML produces a size increase or reshape of dispersed particles due to coalescence of molten material ejected from the target [11,12]. These techniques could allow precise size control of the synthetized nanoparticles.…”

Динамика Теплового Излучения, Сопровождающего Конденсацию Паров Вольфрама В Газообразном И Сверхтекучем Гелии

“…ИЛА является одним из наиболее простых и универсальных методов, дающим возможность получать наночастицы практически из любых материалов, при этом, в отличии от разнообразных химических методов, с чистой поверхностью, не загрязненной какими-либо реагентами. На форму, размеры, химический состав и прочие параметры получаемых в результате абляции продуктов оказывают влияние различные факторы: длина волны лазера, его мощность и длительность импульса, состояние поверхности мишени, а также характеристики среды, в которой проводится абляция [1][2][3]. Как правило, продуктами абляции являются сферические кластеры, чье распределение по размерам обычно описывается логнормальной функцией, а размеры варьируются от единиц до сотен нанометров [1].…”