Energy transfer mechanism of Sm~(3+)/Eu~(3+) co-doped 2CaO-B_2O_3-P_2O_5 phosphors

摘要

Sm~(3+)/Eu~(3+) co-doped calcium borophosphate phosphors were synthesized by solid state reaction method. 2CaO-B_2O_3-P_2O_5: Sm~(3+)/Eu~(3+) co-doped phosphors were characterized by XRD, SEM, 31P solid state NMR, excitation, photoluminescence (PL) and decay profiles. XRD profiles showed that the prepared phosphors exhibit a hexagonal phase in crystal structure and SEM results showed that the particles are more irregular morphologies. From ~(31)P NMR spectra of Sm~(3+)/Eu~(3+) co-doped 2CaO-B_2O_3-P_2O_5 phosphors, the chemical shifts located in the positive frequency region indicating the presence of mono-phosphate complexes Q0-(PO43-). Photoluminescence spectra of Sm~(3+)/Eu~(3+) co-doped 2CaO-B_2O_3-P_2O_5 phosphors show enhancement in emission intensity of Eu~(3+) ion due to co-doping with Sm~(3+) ions through energy transfer process. The energy level mechanism between Sm~(3+) and Eu~(3+) ions has been clearly explained. The energy transfer process has also been evidenced by lifetime decay profiles. These results suggest that the prepared phosphors are potential red luminescent optical materials.