论文部分内容阅读
CaGdAlO_4∶Eu~(3+) powder phosphors were prepared using citrate sol-gel (CSG), half-dry and half-wet (HDW) and solid state (SS) methods, respectively. X-ray diffraction results confirm the formation of CaGdAlO_4∶Eu~(3+) at 900 ℃ (CSG), 1200 ℃ (HDW) and 1400 ℃ (SS), respectively. Field emission scan electron microscopy (FE-SEM) images show that the CaGdAlO_4∶Eu~(3+) powder prepared by the CSG and HDW method has an elliptical shape and that prepared under the SS method has a flaky shape. Upon excitation with 280 nm UV light, all the CaGdAlO_4∶Eu 3+ powders show bright red emission on account of the 4f-4f transitions of the Eu 3+ ions. Moreover, the size of the phosphor particles and the emission intensity increase with the increase of calcined temperature. At the same calcination temperature of 1400 ℃, the 5D_0→7F_2 emission intensity of the sample prepared by HDW method is the highest. Stark components of the 5D_0→7F_J emission transitions, both at room temperature and at a low temperature, reveal that the Eu~(3+) ions occupy only one site with non-centrosymmetry in the crystals.
X-ray diffraction results confirm the formation of CaGdAlO_4: Eu 3+ powder phosphors were prepared using citrate sol-gel (CSG), half-dry and half-wet (HDW) and solid state The emission spectra of CaGdAlO_4: Eu3 + at 900 ℃ (CSG), 1200 ℃ (HDW) and 1400 ℃ (SS), respectively. Field emission scan electron microscopy (FE- After excitation with 280 nm UV light, all the CaGdAlO 4: Eu 3+ powders show bright red emission on account of the 4f -4f transitions of the Eu 3+ ions. Moreover, the size of the phosphor particles and the emission intensity increase with the increase of calcined temperature. At the same calcination temperature of 1400 ° C, the 5D_0 → 7F 2 emission intensity of the sample prepared by HDW method is the highest. Stark components of the 5D_0 → 7F_J emission transitions, both at room temperature an d at a low temperature, reveal that the Eu ~ (3+) ions occupy only one site with non-centrosymmetry in the crystals.