Facile synthesis, structure, and properties of Gd2O2Se

Inorganic phosphors based on rare earth elements are commonly used as scintillation materials due to their high chemical and radiation resistance. In this work, we study gadolinium oxyselenide as a new phosphor material. The work describes a facile synthesis method for Gd2O2Se. Single crystal structure of this compound was determined for the first time: sp.gr. P¯3m1 with a ​= ​3.8911(4) Å and c ​= ​6.8829(8) Å. Gd2O2Se is stable in the inert atmosphere and melts at 2075 ​± ​20 ​°C. This material is also stable when heated in air up to 720 ​°C. with the following oxidation and weight increase. This mass increase can be explained by the oxidation of Se2− to Se4+. Further temperature increase above 952°С leads to a sharp mass loss and the final mass of sample corresponds to full oxidation of Gd2O2Se to gadolinium oxide. The band gap of the material was estimated to be 3.6 ​eV. Photoluminescence spectrum for Gd2O2Se:Tb3+ shows the characteristic transitions in Tb3+ ion with the most intense green emission that corresponds 5D4 → 7FJ transitions. [Display omitted] •A powder of Gd2O2Se was obtained and the single crystal structure was determined: sp.gr. P¯3m1, a ​= ​3.89Å, c ​= ​6.88 Å.•The melting point was found to be 2075 ​± ​20 ​°C. High air stability for this compound was demonstrated up to 720 ​°C.•The estimated value of the band gap is 3.6 ​eV. The photoluminescence of the Tb3+ doped sample was investigated.