A series of energy storage phosphors,Lu2O3:Tb,M(M=Hf,Zr,Ti),were investigated by means of photoand thermoluminescence techniques to compare the effect of the co-dopant from the same group of periodic table of elements...A series of energy storage phosphors,Lu2O3:Tb,M(M=Hf,Zr,Ti),were investigated by means of photoand thermoluminescence techniques to compare the effect of the co-dopant from the same group of periodic table of elements on charge carriers trapping capability and trap parameters.Most of the investigated processes were tracked individually for the Tb3+in the two different metal sites offered by the Lu2O3 host-noncentrosymmetric C2 and centrosymmetric C3i.It is proved that both Tb3+ions participate in hole trapping and electrons are immobilized in traps whose depths are defined by the codopant.Deepest traps,~1.79 eV,appear upon Ti addition,while Zr and Hf generate traps of very similar,~1.40-1.44 eV,depths.The stored energy may be released not only by means of thermal stimulation but also upon the impact of optical photons.Light from the 390-430 nm range of wavelengths was found the most efficient in the latter process.Also deep red radiation of 780 nm releases most of the trapped electrons in Zr/Hf co-doped ceramics but is much less effective in the case of Tb,Ti material.Consistent scheme of electronic levels engaged in charge carriers trapping and subsequent generation of thermoand optically stimulated luminescence was constructed.展开更多
Lutetium oxide nanocrystals codoped with Tm3＋ and Yb3＋ were synthesized by the reverse-like co-precipitation method, using ammonium hydrogen carbonate as precipitant. Effects of the Tm3＋, Yb3＋ molar fractions and ...Lutetium oxide nanocrystals codoped with Tm3＋ and Yb3＋ were synthesized by the reverse-like co-precipitation method, using ammonium hydrogen carbonate as precipitant. Effects of the Tm3＋, Yb3＋ molar fractions and calcination temperature on the structural and upconversion luminescent properties of the Lu2O3 nanocrystals were investigated. The XRD results show that all the prepared nanocrystals can be readily indexed to pure cubic phase of Lu2O3 and indicate good crystallinity. The experimental results show that concentration quenching occurs when the mole fraction of Tm3＋ is above 0.2%. The optimal Tm3＋ and Yb3＋ doped molar fractions are 0.2% and 2%, respectively. The strong blue （490 nm） and the weak red （653 nm） emissions from the prepared nanocrystals were observed under 980 nm laser excitation, and attributed to the 1G4→3H6 and IG4→3F4 transitions of Tm3＋, respectively. Power-dependent study reveals that the 1G4 levels of Tm3＋ can be populated by three-step energy transfer process. The upconversion emission intensities of 490 nm and 653 nm increase gradually with the increase of calcination temperature. The enhancement of the upconversion luminescence is suggested to be the consequence of reducing number of OH- groups and the enlarged nanoerystal size.展开更多
基金Project supported by the Polish National Science Centre(NCN)(#UMO-2014/13/B/ST5/01535)preliminary studies supported by Wroclaw Research Centre EIT+within the project The Application of Nanotechnology in Advanced Materials-NanoMat(POIG.01.01.02-02-002/08)co-financed by the European Regional Development Fund(Innovative Economy Operational Program1.1.2)Experiments with synchrotron radiation were performed at DESY-Hasylab Station in Hamburg and were supported by grant #11-20090289 EC
文摘A series of energy storage phosphors,Lu2O3:Tb,M(M=Hf,Zr,Ti),were investigated by means of photoand thermoluminescence techniques to compare the effect of the co-dopant from the same group of periodic table of elements on charge carriers trapping capability and trap parameters.Most of the investigated processes were tracked individually for the Tb3+in the two different metal sites offered by the Lu2O3 host-noncentrosymmetric C2 and centrosymmetric C3i.It is proved that both Tb3+ions participate in hole trapping and electrons are immobilized in traps whose depths are defined by the codopant.Deepest traps,~1.79 eV,appear upon Ti addition,while Zr and Hf generate traps of very similar,~1.40-1.44 eV,depths.The stored energy may be released not only by means of thermal stimulation but also upon the impact of optical photons.Light from the 390-430 nm range of wavelengths was found the most efficient in the latter process.Also deep red radiation of 780 nm releases most of the trapped electrons in Zr/Hf co-doped ceramics but is much less effective in the case of Tb,Ti material.Consistent scheme of electronic levels engaged in charge carriers trapping and subsequent generation of thermoand optically stimulated luminescence was constructed.
基金Foundation item: Projects (10704090,10774140,11047147)supported by the National Natural Science Foundation of ChinaProjects (KJ090514,KJTD201016)supported by the Natural Science Foundation of Chongqing Municipal Education Commission,China
文摘Lutetium oxide nanocrystals codoped with Tm3＋ and Yb3＋ were synthesized by the reverse-like co-precipitation method, using ammonium hydrogen carbonate as precipitant. Effects of the Tm3＋, Yb3＋ molar fractions and calcination temperature on the structural and upconversion luminescent properties of the Lu2O3 nanocrystals were investigated. The XRD results show that all the prepared nanocrystals can be readily indexed to pure cubic phase of Lu2O3 and indicate good crystallinity. The experimental results show that concentration quenching occurs when the mole fraction of Tm3＋ is above 0.2%. The optimal Tm3＋ and Yb3＋ doped molar fractions are 0.2% and 2%, respectively. The strong blue （490 nm） and the weak red （653 nm） emissions from the prepared nanocrystals were observed under 980 nm laser excitation, and attributed to the 1G4→3H6 and IG4→3F4 transitions of Tm3＋, respectively. Power-dependent study reveals that the 1G4 levels of Tm3＋ can be populated by three-step energy transfer process. The upconversion emission intensities of 490 nm and 653 nm increase gradually with the increase of calcination temperature. The enhancement of the upconversion luminescence is suggested to be the consequence of reducing number of OH- groups and the enlarged nanoerystal size.
