Eu3＋ doped CaWO4 with tetragonal system were prepared at comparatively low temperature （125 ℃） in ethylene glycol medium. The phosphor was further investigated by X-ray difffactometer （XRD）, photoluminescence sp...Eu3＋ doped CaWO4 with tetragonal system were prepared at comparatively low temperature （125 ℃） in ethylene glycol medium. The phosphor was further investigated by X-ray difffactometer （XRD）, photoluminescence spectrophotometer （PL）, Fourier transform infra red （FT-IR） spectroscopy and transmission electron microscopy （TEM）. XRD analysis indicated a decrease in the unit cell volume of CaWO4 with increasing Eu3＋ ion concentration. It indicated the homogeneous substitution of Ca2＋ ions in CaWO4 by the Eu3＋ ions. TEM images showed that the particle size ranged from 20 to 200 nm and it could extend the application of the nanoparticles. The photoluminescence study showed that the intensity of electric dipole transition （SD0→TF2） at 614 nm dominated over the magnetic dipole transition （SD0→TFx） at 592 nm. The optimum concentration of Eu3＋ for the highest luminescence was found to be 20 at.%. The as prepared samples were found to be dispersible in water and methanol.展开更多
The influence of different solvents and metal ions （Li^＋, Ba^2＋, Bi^3＋） on the crystallization behaviour, morphology and enhancement in photoluminescence intensity of Dy^3＋ doped CePO4 were investigated. Highly ...The influence of different solvents and metal ions （Li^＋, Ba^2＋, Bi^3＋） on the crystallization behaviour, morphology and enhancement in photoluminescence intensity of Dy^3＋ doped CePO4 were investigated. Highly crystalline luminescent nanophosphors of CePO4：DY^3＋ re-dispersible in polar solvents were successfully prepared via a simple polyol route at 140 ℃. As-prepared Dy^3＋ doped CePO4 nanophosphors prepared in EG and DMF appeared to have crystalline monoclinic phase but exhibited hexagonal phase when prepared in water and water mixed solvents, The hexagonal phase transformed to monoclinic phase after heating at 900 ℃. TEM study revealed different shapes of the synthesized nanophosphors with change of solvents. The luminescence intensity of 4F9/2→6H15/2 at 478 nm （blue） was found to be more prominent than 4F9/2→6H13/2 at 572 nm （yellow）. The introduction of metal ions （Li＋, Ba2＋ and Bi3＋） in CePO4：Dy3＋ led to considerable luminescent enhancement. The nanophosphors were subsequently incorporated in polymer films of PVA which showed the characteristic emissions of Dy3＋. It also served as an effective method to improve the performance of polymer materials and brought about novel properties in them.展开更多
基金Project supported by the Department of Science and Technology (DST), New Delhi, Govt. of India
文摘Eu3＋ doped CaWO4 with tetragonal system were prepared at comparatively low temperature （125 ℃） in ethylene glycol medium. The phosphor was further investigated by X-ray difffactometer （XRD）, photoluminescence spectrophotometer （PL）, Fourier transform infra red （FT-IR） spectroscopy and transmission electron microscopy （TEM）. XRD analysis indicated a decrease in the unit cell volume of CaWO4 with increasing Eu3＋ ion concentration. It indicated the homogeneous substitution of Ca2＋ ions in CaWO4 by the Eu3＋ ions. TEM images showed that the particle size ranged from 20 to 200 nm and it could extend the application of the nanoparticles. The photoluminescence study showed that the intensity of electric dipole transition （SD0→TF2） at 614 nm dominated over the magnetic dipole transition （SD0→TFx） at 592 nm. The optimum concentration of Eu3＋ for the highest luminescence was found to be 20 at.%. The as prepared samples were found to be dispersible in water and methanol.
基金Project supported by Department of Science and Technology of India
文摘The influence of different solvents and metal ions （Li^＋, Ba^2＋, Bi^3＋） on the crystallization behaviour, morphology and enhancement in photoluminescence intensity of Dy^3＋ doped CePO4 were investigated. Highly crystalline luminescent nanophosphors of CePO4：DY^3＋ re-dispersible in polar solvents were successfully prepared via a simple polyol route at 140 ℃. As-prepared Dy^3＋ doped CePO4 nanophosphors prepared in EG and DMF appeared to have crystalline monoclinic phase but exhibited hexagonal phase when prepared in water and water mixed solvents, The hexagonal phase transformed to monoclinic phase after heating at 900 ℃. TEM study revealed different shapes of the synthesized nanophosphors with change of solvents. The luminescence intensity of 4F9/2→6H15/2 at 478 nm （blue） was found to be more prominent than 4F9/2→6H13/2 at 572 nm （yellow）. The introduction of metal ions （Li＋, Ba2＋ and Bi3＋） in CePO4：Dy3＋ led to considerable luminescent enhancement. The nanophosphors were subsequently incorporated in polymer films of PVA which showed the characteristic emissions of Dy3＋. It also served as an effective method to improve the performance of polymer materials and brought about novel properties in them.
