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

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 (4F3/2 → 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.