Synthesis, characterization and optical properties of nanosized lanthanum (III) complexes thin film with aryl-azo-pyrogallol derivatives.

The present study is focused on the assembly of two new thin films based on the direct layer deposition of lanthanum ion from solution with two aryl-azo-pyrogallol ligands onto the surface of a glass substrate. Assembled lanthanum (III) complexes were characterized by different techniques including thermal gravimetric analysis, metal analysis by acid digestion and complexometric titration, Fourier transforms infrared, transmission electron microscopy, and X-ray diffraction. Two complexes were highly similar in their patterns and crystallinities with the characterized particle size range 23.16-23.31 nm. Energy gaps of the two complexes NS NaLa(III)-(L1) and NS NaLa(III)-(L2) were found to be 2.09 and 2.33 eV, respectively. Linear and calculated nonlinear optical properties have been studied for the two complexes. The nonlinear refractive index has been calculated and NS NaLa(III)-(L2) showed a high nonlinear behavior (n = 8 × 10 esu) and it could be a promising low-cost material in the optical nonlinear application.