摘要
A serials of novel Ba_2Mg(PO_4)_2:Eu~(3+) and BaMgP_2O_7:Eu~(3+) red-emitting phosphors were synthesized by solid-state reaction method,and their crystal structures were refined by the Rietveld method using powder X-ray diffraction(XRD) data.Ba_2Mg(PO_4)_2:Eu~(3+) and BaMgP_2O_7:Eu~(3+)crystallize in P2_1/n space group,with Eu~(3+) and Ba~(2+)occupy the same site.Under UV excitation at393 nm(~7F_0→~5L_6 transition),both Ba_2Mg(PO_4)_2:Eu~(3+) and BaMgP_2O_7:Eu~(3+) exhibit red emission with two main peaks at 592 nm and 613 nm,corresponding to the ~5D_0→~7F_1 and ~5D_0→~7F_2 transitions of Eu~(3+),respectively.The excitation spectra monitored at 592 and 613 nm show a wide band peaked around 248 nm and several sharp lines,with domain peak centered at 393 nm.The former band is attributed to transition towards the charge-transfer state(CT) due to O~(2-)-Eu~(3+) interaction.The prevailing peak at 613 nm in Ba_2Mg(PO_4)_2:Eu~(3+) corresponds to the hypersensitive transition.It indicates that Eu~(3+) ion is located in an asymmetric cation environment in Ba_2Mg(PO_4)_2:Eu~(3+).Whereas,the intensity of the peak at 592 nm is much stronger in Ba_2Mg(PO_4)_2 under the same excitation wavelength.It is obvious that Eu~(3+) ions are expected to substitute for different sites in Ba_2Mg(PO_4)_2 and BaMgP_2O_7 lattice.Intensity of Eu~(3+)as far apart as Ba_2Mg(PO_4)_2 and BaMgP_2O_7is interpreted based on the difference of crystal structure.In this work,a dopant site occupancy mechanism is proposed which could be taken as a general method to find new high color purity red phosphors.
A serials of novel Ba_2Mg(PO_4)_2:Eu~(3+) and BaMgP_2O_7:Eu~(3+) red-emitting phosphors were synthesized by solid-state reaction method,and their crystal structures were refined by the Rietveld method using powder X-ray diffraction(XRD) data.Ba_2Mg(PO_4)_2:Eu~(3+) and BaMgP_2O_7:Eu~(3+)crystallize in P2_1/n space group,with Eu~(3+) and Ba~(2+)occupy the same site.Under UV excitation at393 nm(~7F_0→~5L_6 transition),both Ba_2Mg(PO_4)_2:Eu~(3+) and BaMgP_2O_7:Eu~(3+) exhibit red emission with two main peaks at 592 nm and 613 nm,corresponding to the ~5D_0→~7F_1 and ~5D_0→~7F_2 transitions of Eu~(3+),respectively.The excitation spectra monitored at 592 and 613 nm show a wide band peaked around 248 nm and several sharp lines,with domain peak centered at 393 nm.The former band is attributed to transition towards the charge-transfer state(CT) due to O~(2-)-Eu~(3+) interaction.The prevailing peak at 613 nm in Ba_2Mg(PO_4)_2:Eu~(3+) corresponds to the hypersensitive transition.It indicates that Eu~(3+) ion is located in an asymmetric cation environment in Ba_2Mg(PO_4)_2:Eu~(3+).Whereas,the intensity of the peak at 592 nm is much stronger in Ba_2Mg(PO_4)_2 under the same excitation wavelength.It is obvious that Eu~(3+) ions are expected to substitute for different sites in Ba_2Mg(PO_4)_2 and BaMgP_2O_7 lattice.Intensity of Eu~(3+)as far apart as Ba_2Mg(PO_4)_2 and BaMgP_2O_7is interpreted based on the difference of crystal structure.In this work,a dopant site occupancy mechanism is proposed which could be taken as a general method to find new high color purity red phosphors.
引文
