Synthesis and temperature dependent luminescence investigation of GdOCl:Ce3+ powders

Gadolinium oxychloride (GdOCl) powders doped with various concentrations of Ce3+ were synthesized via heat-treatment of hydrated gadolinium chloride. The reaction pathway to produce GdOCl by heat treating GdCl3·xH2O was explored through a combination of thermal analysis and X-Ray Diffraction (XRD) techniques, leading to the proposition of possible chemical reactions that describe the underlying mechanism of this complex process. The reversible hydration behavior observed in GdOCl:Ce has been leveraged to examine the possible impact of Gd(OH)2Cl:Ce on the optical characteristics of GdOCl:Ce. Studies comparing the luminescence properties of mixed GdOCl:Ce/Gd(OH)2Cl:Ce and pure GdOCl:Ce samples were conducted over a temperature range of 12–300K. These comparative analyses revealed analogous complex photoluminescence emissions between 350 and 600 nm, along with comparable lifetime characteristics for both GdOCl:Ce and Gd(OH)2Cl:Ce. The broad emission peak around 500 nm is likely associated with the oxide sublattice in GdOCl:Ce and may be attributed to emissions related to the host lattice or color center defects. These defects are likely responsible for the rapid decay components (<20 ns) observed in the luminescence decay.