VUV excited luminescence of Gd0.9Eu0.1BO3 nanophosphor prepared by aqueous sol-gel method

Orthoborate nanopowder phosphor, with formulation Gd0.90Eu0.1BO3 has been synthesized by aqueous sol-gel method, and then annealed at 1000, 1100 and 1200 °C. The crystal structure and the morphology of the as prepared materials were cheeked using several techniques such as: IR, XRD, and SEM. The experimental results show that the synthesized nanoparticles have a primary average diameter of approximately 150-250 nm. The samples crystallize mainly in the vaterite structure. Despite that the signature of triangular borate group BO33- more characteristics of the calcite form is observed in the FTIR spectra indicating that some Eu3+ ions are embedded in parasitic phase such as calcite form. The VUV excitation spectra of the samples were recorded at room temperature and lead to selectivity for the VUV excited emission confirming that the overall emission come from the Eu3+ ions embedded in at least two crystallographic structures. However, the contribution from Eu3+ ions embedded in parasitic phase contribute weakly to the overall emission. The luminescence properties of the prepared phosphors were characterized also by its kinetic decay. The results show that luminescence decaying correlated the observations made for both excitation and emission spectra.