Characteristics of nLnvo4:Eu3+ (Ln = La, Gd, Y, Sm) sols with nanoparticles of different shapes and sizes

Abstract

Colloidal aqueous solutions of nanocrystals based on LnVO4:Eu 3+ (Ln = La, Gd, Y, Sm) with different form factors and sizes from 2 to 300 nm were obtained. The main characteristics (volume, mass, density, specific surface area) of these disperse systems in the solid phase were calculated based on transmission electron mi- croscopy data. UV/Vis spectroscopy was used to show that light absorption depended linearly on the nanoparticle concentration in solution in the range 5⋅10 -5 —1⋅10 -3 M (0.01-0.25 g/L). Extinction coefficients of Introduction. Much attention is currently focused on the properties of various nanomaterials in solutions. Nanocrystalline luminophores based on broad-band semiconductors and dielectrics activated by lanthanides (Ln) are es- pecially interesting. Activated nanocrystals are attractive owing to several properties that are promising for use in op- tics, chemistry, biology, and medicine (1, 2). The most important features of such materials are high photostability, a large luminescence Stokes shift, the lack of a scintillating effect, stability of narrow luminescence spectral lines, and relatively low toxicity. Liquid-phase synthetic methods are some of the most simple and convenient ways of preparing small-sized nanocrystals (up to several nanometers) (3, 4). In particular, low-temperature colloidal synthesis can produce stable colloidal solutions of nanocrystalline systems. The size and shape of nanoparticles (NP) can be controlled by varying the chemical reaction conditions. The study of the physicochemical and optical properties of such disperse systems has fundamental and applied significance in physics, chemistry, and biology. Herein we present results from a determina- tion of the volume, mass, density, and specific surface area of activated NP-luminophores based on Ln orthovanadates