Luminescent Properties of a Solid-Phase Composite Based on Zirconium, Rare Earth Elements (Er, Nd) and Molybdenum

Abstract

As a result of the chemical synthesis, a heterogeneous compound with luminescent properties was obtained, containing rare-earth metal ions (Er³⁺, Nd³⁺), Mo⁶⁺, and Zr⁴⁺. The reaction was carried out using solutions of Na₂MoO₄, ZrOCl₂, NdCl₃, and ErCl₃ at a temperature of 22 °C. After 30─35 days, the system reached equilibrium, and an insoluble greyish-blue precipitate was formed. ICP-AES analysis confirmed the presence of all the initial components and showed the heterogeneity of the material; the molar ratio nNa : nMo : nZr : nEr : nNd = 0.05 : 0.22 : 0.086 : 0.082 : 0.05 was confirmed in the system. X-ray microanalysis revealed a complex multiphase structure characterized by significant chemical diversity and the presence of nanoparticles. Partial emission of Nd³⁺ at a wavelength of around 885 nm (⁴F_3/2 → 4I⁹/₂ transition) was found by luminescence investigations; this can be utilised in medical near-infrared laser systems. Spectrometer constraints prevented the detection of Er³⁺ emission. The material's molybdenum-based structure and the presence of Zr⁴⁺ ions are responsible for the visible glow. Although more research is necessary to completely comprehend the Er³⁺ emission, the acquired findings suggest the possibility of developing complex heterogeneous luminous compounds containing rare earth ions for optical and medicinal applications.