The possible defect models of Y^3＋：PbWO4 crystals are discussed by defect chemistry and the most possible substituting positions of the impurity Y^3＋ ions are studied by using the general utility lattice program （...The possible defect models of Y^3＋：PbWO4 crystals are discussed by defect chemistry and the most possible substituting positions of the impurity Y^3＋ ions are studied by using the general utility lattice program （GULP）. The calculated results indicate that in the lightly doped Y^3＋ ：PWO crystal, the main compensating mechanism is [2Ypb^＋ ＋ VPb^2-], and in the heavily doped Y^3＋ ：PWO crystal, it will bring interstitial oxygen ions to compensate the positive electricity caused by YPb^＋, forming defect clusters of [2Ypb^＋ ＋Oi^2-] in the crystal. The electronic structures of Y3＋ ：PWO with different defect models are calculated using the DV-Xα method. It can be concluded from the electronic structures that, for lightly doped cases, the energy gap of the crystal would be broadened and the 420nm absorption band will be restricted; for heavily doped cases, because of the existence of interstitial oxygen ions, it can bring a new absorption band and reduce the radiation hardness of the crystal.展开更多
Emission spectra,longitudinal transmission and light output for the Sb-doped and Y-doped PbWO_(4) crystals are presented.Scintillation decay kinetics has been measured by using gate integration and single photon count...Emission spectra,longitudinal transmission and light output for the Sb-doped and Y-doped PbWO_(4) crystals are presented.Scintillation decay kinetics has been measured by using gate integration and single photon counting method with blue and green filters.Radiation hardness has also been measured by using ^(60)Coγ-ray irradiation under different dose rates and different dose rate profiles.The light yield and radiation hardness of the Sb-doped and Y-doped PbWO_(4) crystals are improved as compared to the undoped crystals and are suitable for the requirements of compact muon solenoid.展开更多
Novel twin-Christmas tree-like PbWO4 microcrystals have been prepared via a convenient aqueous solution route at room temperature under the assistance of 13- cyclodextrin （13-CD）. The product was characterized by XR...Novel twin-Christmas tree-like PbWO4 microcrystals have been prepared via a convenient aqueous solution route at room temperature under the assistance of 13- cyclodextrin （13-CD）. The product was characterized by XRD, EDX, SEM, TEM, UV-vis and PL and BET techniques. It was found that 13-CD plays an important role in the forming of twin-Christmas tree-like PbWO4 microcrystals. A five-step growth mechanism was proposed to explain the formation of such twin-Christmas tree-like structures. The photocatalytic performance of PbWO4 microcrystals was evaluated by measuring the decomposition rate of methylene blue （MB） and malachite green （MG） solution under the UV irradiation, and the photocatalytic results indicated that as-prepared PbWO4 microcrystals exhibit good and versatile photocatalytic activity as well as excellent recyclability.展开更多
文摘The possible defect models of Y^3＋：PbWO4 crystals are discussed by defect chemistry and the most possible substituting positions of the impurity Y^3＋ ions are studied by using the general utility lattice program （GULP）. The calculated results indicate that in the lightly doped Y^3＋ ：PWO crystal, the main compensating mechanism is [2Ypb^＋ ＋ VPb^2-], and in the heavily doped Y^3＋ ：PWO crystal, it will bring interstitial oxygen ions to compensate the positive electricity caused by YPb^＋, forming defect clusters of [2Ypb^＋ ＋Oi^2-] in the crystal. The electronic structures of Y3＋ ：PWO with different defect models are calculated using the DV-Xα method. It can be concluded from the electronic structures that, for lightly doped cases, the energy gap of the crystal would be broadened and the 420nm absorption band will be restricted; for heavily doped cases, because of the existence of interstitial oxygen ions, it can bring a new absorption band and reduce the radiation hardness of the crystal.
基金Supported by the National Natural Science Foundation of China under Grant No.59932002.
文摘Emission spectra,longitudinal transmission and light output for the Sb-doped and Y-doped PbWO_(4) crystals are presented.Scintillation decay kinetics has been measured by using gate integration and single photon counting method with blue and green filters.Radiation hardness has also been measured by using ^(60)Coγ-ray irradiation under different dose rates and different dose rate profiles.The light yield and radiation hardness of the Sb-doped and Y-doped PbWO_(4) crystals are improved as compared to the undoped crystals and are suitable for the requirements of compact muon solenoid.
文摘Novel twin-Christmas tree-like PbWO4 microcrystals have been prepared via a convenient aqueous solution route at room temperature under the assistance of 13- cyclodextrin （13-CD）. The product was characterized by XRD, EDX, SEM, TEM, UV-vis and PL and BET techniques. It was found that 13-CD plays an important role in the forming of twin-Christmas tree-like PbWO4 microcrystals. A five-step growth mechanism was proposed to explain the formation of such twin-Christmas tree-like structures. The photocatalytic performance of PbWO4 microcrystals was evaluated by measuring the decomposition rate of methylene blue （MB） and malachite green （MG） solution under the UV irradiation, and the photocatalytic results indicated that as-prepared PbWO4 microcrystals exhibit good and versatile photocatalytic activity as well as excellent recyclability.
