Structural, morphological and emissive properties of rare earth-doped Y₂O₃ synthesized by hydrothermal method

Transparent polycrystalline ceramics have been developed in response to the growing demand for new materials with multiple applications in advanced technologies. Yttrium oxide (Y₂O₃) is a ceramic material, intensively studied due to its superior qualities, which include optical clarity, biocompatibility, and chemical and thermal stability. In biotechnology, it can be used to create fluorescent labels, drug delivery systems, antimicrobial materials, lasers, and protective windows, among other applications. This paper aims to clarify certain methodological issues related to the synthesis of Y₂O₃ doped with rare earth ions. In this regard, a hydrothermal process involving the use of nitrates as a cation source, along with urea and polyethylene glycol, was employed. The influence of the process parameters (the type and concentration of raw materials, reaction time and temperature, the influence of surfactant and intermediate steps, etc.) on the properties of Y₂O₃ was analyzed. Furthermore, the effectiveness of oxide doping was also evaluated. FTIR spectroscopy and X-ray diffraction were used to determine the chemical bonds, crystal structure, and purity of the material. The morphological properties influence the applicability of the oxide in the biotechnology field, so as not to raise toxicity problems in the liver or kidneys. The particles' rounded edges and spherical shape were visible under SEM microscopy. Studies on the optical properties confirmed the efficiency and applicability of the proposed method for obtaining yttrium oxide-based ceramics with potential applications in biotechnology.

Acknowledgements: This work was supported by a grant from the Ministry of Research, Innovation and Digitization, CNCS-UEFISCDI, project number PN-IV-P2-2.1-TE-2023-0417 (BioYDetect, Contract no. 30TE/2025), within PNCDI IV, and by the Core Program within the National Research Development and Innovation Plan 2022-2027, project no. 2307.