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4Laser-induced alloying and crystallization of multielement
nanostructures in liquids
N. Tarasenka , v. Kurnev , n. laraseiiku
1-B.I. Stepanov Institute of Physics, National Academy of Sciences ofBelarus, 68-2 Nezalezhnasti Ave., 220072 Minsk, Belarus 2- Nanotechnology and Integrated Bio-Engineering Centre, Ulster University, Belfast, UK
Multielement nanostructures, such as perovskites and high entropy alloys have a wide range of applications in different fields, including catalysis, magnetism, biomedical science, photovoltaics, etc. However, preparation of such nanostructures with attaining a composition control poses a persistent challenge. Pulsed laser irradiation (PLI) in liquid can be an effective technique for alloying and crystallization of multielement nanostructures, as laser irradiation can induce targeted changes in the structural and physical properties of nanoparticles (NPs), that makes laser-induced modification of NPs a relevant topic in the last decades [1,2]. By varying laser pulse duration, wavelength and fluence, a precise control of NPs inner structure and surface composition can be achieved.
For multielement nanomaterials synthesis, PLI can be used in different ways: for example, laser irradiation of the colloidal mixtures, laser ablation of preliminary prepared multielement targets or laser processing of the deposited multicomponent thin films under liquid layer in a surface scanning mode, that results in a fabrication of multielemental nanostructured films on a substrate (Fig. 1). In this study, we have applied PLI of multimetallic CuZnFeMo colloids and PbZrTi layers deposited on the silicon substrate aiming synthesis of nanostructures with nearly equiatomic element composition in the first case and polycrystalline Pb(Zr0.5Ti0.5)O3 ferroelectric films in the second case. As a laser source, the unfocused beams of the second and forth harmonic (wavelength 532 and 266 nm, respectively) of the Nd:YAG laser (LOTIS TII, LS2134D) were used for laser-induced modification. The laser operated at repetition rate 10 Hz and pulse duration 10 ns. The phase composition, morphology, structure and optical properties of the prepared nanostructures were investigated. The results demonstrated that crystalline Pb(Zr0.5Ti0.5)O3 films were formed on Si substrates during 532 nm laser irradiation of deposited seeded three-phasic colloidal precursors. In the conditions created, the formation of multielemental phases proceeds via generation of thermal energy by photoexcitation, followed by co-melting, and re-solidification processes at high cooling rates under optimized laser processing parameters. The results obtained demonstrated that PLI of colloidal NPs provides unique possibilities not only for a change of the NPs morphology, but also for the synthesis of compound and alloyed NPs with a control over their phase composition.
The work was supported by the National Academy of Sciences of Belarus under project Convergence 2.2.05 and by the Belarusian Foundation for Fundamental Researches under Grant F23RNF-156.
[1] D. Zhang, B. Gokce, S. Barcikowski, Laser Synthesis and Processing of Colloids: Fundamentals and Applications, Chem. Rev., vol. 117, pp. 3990-4103, (2017).
[2] N.N. Tarasenka, N.V. Tarasenko, V.V. Pankov, Preparation of Germanium-Tin Alloy Nanoparticles by Laser-Assisted Techniques in Liquid, Intern. J. of Nanoscience, vol. 18, p. 1940049, (2019).
Fig. 1. A principal scheme of laser assisted synthesis and modification experiments used for PZT perovskite nanomaterials preparation performed with colloids and thin films.
deposited nanoparticles
