Synthesis and Characterization of Novel Nanoparticles of Lithium Aluminum Iodate LiAl(IO3)4, and DFT Calculations of the Crystal Structure and Physical Properties

Abstract

Here we report on the non-hydrothermal aqueous synthesis and characterization of nanocrystalline lithium aluminum iodate, LiAl(IO3)4. Morphological and compositional analyses were carried out by using scanning electron microscopy (SEM) and energy-dispersive X-ray measurements (EDX). The optical and vibrational properties of LiAl(IO3)4 have been studied by UV-Vis and IR spectroscopy. LiAl(IO3)4 is found to crystallize in the non-centrosymmetric, monoclinic P21 space group, contrary to what was reported previously. Theoretical simulations and Rietveld refinements of crystal structure support this finding, together with the relatively high Second Harmonic Generation (SGH) response that was observed. Electronic band structure calculations show that LiAl(IO3)4 crystal has an indirect band gap Egap=3.68 eV, in agreement with the experimental optical band gap Egap=3.433 eV. The complex relative permittivity and the refraction index of LiAl(IO3)4 have also been calculated as a function of energy, as well as its elastic constants and mechanical parameters. LiAl(IO3)4 is found to be a very compressible and ductile material. Our findings imply that LiAl(IO3)4 is a promising material for optoelectronic and non -linear optical applications.

Pressure-induced phase transition and increase of oxygen-iodine coordination in magnesium iodate

“…For instance, by introducing Nb 5+ cations in metal iodates, Sun et al [3] successfully * daniel.errandonea@uv.es synthesized BaNbO(IO 3 ) 5 , which has a SHG response 14 times larger than that of the currently widely used NLO materials, i.e., potassium dihydrogen phosphate (KH 2 PO 4 ), usually known as KDP. Moreover, metal iodates usually exhibit transparency in a wide wavelength region [11,12], high optical-damage thresholds, and high thermal stability [5,6,13], which make them the choice for the next generation of NLO materials.…”

Solution‐Based Synthesis Routes for the Preparation of Noncentrosymmetric 0‐D Oxide Nanocrystals with Perovskite and Nonperovskite Structures

“…Similarly, nanoparticles of LiAl(IO 3 ) 4 belonging to the low‐symmetry P 2 1 space group have also been obtained after a simple coprecipitation in water and solvent evaporation thus leading to partially agglomerated but well‐crystallized NCO nanomaterials. [ 63 ] However, for iodate compounds that easily precipitate in acidic solutions, solubility issues and long‐term chemical stability are in this case to be considered before any further surface chemical modifications in water‐based media. Regarding functional nanocomposites, nonlinear optical thin films of SiO 2 (and of Laponite) with embedded SHG‐active α‐LiIO 3 nanocrystals can also be readily prepared from dip‐coated solution precursors containing the dissolved lithium iodate salt.…”

“…The above kinetic aspects and growth mechanisms, when reported in the literature, are indicated in the next sections of this review only dedicated to 0-D dielectric nanomaterials and whose global outline is largely inspired from the excellent contributions of Charles et al [56] and Schnepp et al [57] Very notably, the overall complexity of NCO nanocrystals has recently been increased in terms of chemical compositions with the synthesis of three-and four-cation perovskites belonging to high-symmetry point groups, [8,58] in terms of new functional optical properties with the doping by fluorescent rare-earth ions, [59][60][61] in terms of crystalline structures with new hosts belonging to low-symmetry point groups [62,63] and finally, in terms of surface functionalization for bioimaging [64,65] and for the two-photon-triggered photorelease of caged compounds in advanced drug-delivery theranostic applications. [66,67] In parallel, the experimental techniques (TEM imaging, synchrotron radiations, pair distribution function analysis of the Bragg and diffuse scattering components, SAXS, real-time UV-Vis, FTIR, DLS, SHG, and AFM-based experiments, etc.)…”