Pulse Duration and Wavelength Effects of Laser Ablation on the Oxidation, Hydrolysis, and Aging of Aluminum Nanoparticles in Water

Abstract

We analyzed the formation of the aluminum (Al) nanoparticles (NPs) with triangular shape obtained by ablating Al bulk in liquid using pulses with different durations (5 ns, 200 ps, and 30 fs) and wavelengths (355 nm, 800 nm, and 1064 nm). We report three stages of synthesis and aging of Al NPs: Formation, transformation, and stable stage. The NPs prepared by different pulses are almost identical at the initial stage. The effects of duration and wavelength of the ablation pulses on the aging of NPs are revealed. Pulse duration is determined to be essential for morphological transformation of NPs, while pulse wavelength strongly influences particle sizes. NPs produced by ultra-short pulses have smaller sizes and narrow size distribution. We demonstrate that oxidation and hydrolysis of Al in water are the results of ablation for all pulse durations and wavelengths, which also strongly modify the preferable reaction path of NPs in water, thus affecting the composition and morphology of triangle NPs. The results of modeling of the NPs generation in water due to a 50 ps laser pulse interacting with a thick Al target are presented. Water-based effects in the formation of NPs, their evolution, and solidification are considered from the mechanical and thermophysical points of view. The detailed analysis of the modeling results allowed for determination of the main mechanism responsible for the ablation process followed by the NPs formation.

Diverse nanomaterials synthesized by laser ablation of pure metals in liquids

“…Oxide phases are also producible in organic solvents. For example, γ-Al 2 O 3 particles are generated by LAL of Al in ethanol, and post-treatment by means of laser irradiation can only change the particle size, incapable of altering the phases [342], as shown in Table 9 [343][344][345][346][347][348][349][350][351].…”

“…Under hydrothermal conditions of 320°C-400°C and 1.5-10 MPa, α-Al 2 O 3 can be formed, whereas γ-Al 2 O 3 formation needs almost the same pressure but requires a high temperature above 400°C [355]. The reason why pure stable [351] α-Al 2 O 3 and γ-Al 2 O 3 particles with abnormal sizes can be produced by LAL is still a challenge to be addressed. In aqueous solutions including water, γ-, δ-, θ-, and α-Al 2 O 3 are producible with additional products of H + /Al 2+ codoped alumina [356] and β-NaAlO 2 [349].…”

Influence of Laser Process Parameters, Liquid Medium, and External Field on the Synthesis of Colloidal Metal Nanoparticles Using Pulsed Laser Ablation in Liquid: A Review

“…The ablation of aluminium (Al) targets in distilled water was analysed at different pulse durations (i.e., 5 ns, 200 ps, and 30 fs) by Zhang et al [108]. Moreover, the suspensions resulted in variations in colour (nanosecond pulses showed a white colour, picosecond pulses showed a light grey colour, and femtosecond pulses showed a brown colour) due to surface plasmon effects.…”

“…However, deciding which parameter plays a decisive role in the resultant formation of the desired NPs remains a challenge. Furthermore, we found studies on PLAL [34,67,72,92,[98][99][100][101][102][103][104][105][106][107][108][109][110][111] that focused on single-parameter evaluation; however, the area of multiparametric analysis of laser parameters on nanoparticle formation can be explored.…”

SrAl2O4: Eu2+, Dy3+ doped-nanoparticles prepared by pulsed laser ablation in liquids

“…In case of PLAL techniques, laser parameters (such as wavelength, pulse duration, laser energy) and the liquid environment (solvent, temperature, surfactant for instance) are the key points to optimize as reported in Table 1. Larger NPs with increase laser fluence 8 Increase of the size distribution with fs and ps lasers 9 Small increase of the size distribution with rep. rate 10 Higher yield for increase absorption 11 With the increasing need of nanoparticles to be used in various applications, more and more researches focus on rare-earth doped nanoparticles. Rare-earth and transition metal doped nanoparticles present good photostability and wide possible optical features including the well-known up-conversation, down-conversation and persistent luminescence processes 12 .…”