Description
The controlled synthesis of nanomaterials with defined size, morphology, and high purity remains a central objective in modern nanotechnology due to their distinctive optical, electronic, and catalytic properties. Among available fabrication approaches, Pulsed Laser Ablation in Liquids (PLAL), also referred to as Laser Ablation Synthesis in Solution (LASiS), has emerged as a versatile and efficient physical technique. In contrast to conventional chemical reduction methods, PLAL is a ligand-free and environmentally benign process that does not require surfactants, reducing agents, or complex precursors. This advantage is particularly important for catalytic and biomedical applications, where surface contamination can significantly affect intrinsic material performance.
Layered quaternary chalcogenides, particularly FeGaInS₄, represent a promising class of materials for optoelectronic and magnetic applications due to their anisotropic crystal structure and the incorporation of transition metal ions. However, the transformation of bulk FeGaInS₄ crystals into nanoparticles via PLAL has not yet been comprehensively reported. In this study, FeGaInS₄ nanoparticles were successfully synthesized using the PLAL technique.
Fig I) Synthesis process of PLAL II) PL spectra of (a) bulk FeGaInS4crystal and (b) FeGaInS4 NP after laser ablation.
Structural analysis based on Williamson–Hall (W–H) evaluation reveals a substantial increase in the average crystallite size from 35.4 nm (bulk) to 105.1 nm after laser ablation, indicating enhanced long-range crystalline order. Simultaneously, the microstrain decreased from 6.09 × 10⁻⁷ to −0.6 × 10⁻⁷, reflecting a transition from tensile to compressive residual stress. Photoluminescence (PL) analysis demonstrates a pronounced blue shift of the emission maximum from 855 nm (bulk) to 652 nm (nanoparticles), corresponding to an increase in the optical band gap from approximately 1.45 eV to 1.89 eV. This band gap widening is attributed to the quantum confinement effect, which becomes significant when crystallite dimensions approach the exciton Bohr radius. Under such conditions, continuous energy bands evolve into discrete energy levels, leading to an expansion of the band gap between the valence and conduction bands.These findings confirm that PLAL provides an effective route for producing high-purity FeGaInS₄ nanoparticles with tunable structural and optical properties.
