Particle size effect on structural and optical properties of Y2O3:Nd3+ nanoparticles prepared by coconut water-assisted sol-gel route

Pure and Nd3+ doped Y2O3 samples were produced under different calcination conditions via a modified sol-gel route. The powders were characterized by Extended X-Ray Absorption Fine Structure (EXAFS), X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and photoluminescence (PL) measurements. EXAFS measurement at Y K edge of amorphous powders showed a more organized structure for samples produced at higher pH of starting sol, which in turn facilitated the crystallization of the cubic Y2O3 phase at lower temperatures. On the other hand, the quantitative EXAFS analysis of the crystalline samples showed that the produced nanomaterials presented a high degree of crystallinity, even for samples with the crystallite sizes of about 6 nm. The behavior of fluorescence emission intensity of Nd doped samples was studied considering the influence of adsorbed molecules onto particle' surfaces and energy transfer processes between the dopant ions.