The red long-lasting phosphorescent （LLP） of β-Zn3（POa）2：Mn2＋,pr3＋ material was prepared through combustion and conventional solid-state sintering methods. The influence of Pr3＋ ions on luminescence and LLP o...The red long-lasting phosphorescent （LLP） of β-Zn3（POa）2：Mn2＋,pr3＋ material was prepared through combustion and conventional solid-state sintering methods. The influence of Pr3＋ ions on luminescence and LLP of Mn2＋ in 13-Zn3（POa）2：Mn2＋,pr3＋ phosphor was systematically investigated. The phosphor presented a strong photoluminescence peak at 620 nm attributed to the 4T1g→ 6A1 g transition of Mn2＋ ions in octahedral coordination. Red LLP was observed in β-Zn3（PO4）2：Mn2＋,Pr3＋ phosphors with persistence time for more than 2 h. It was found that the long persistent phosphorescent performance of Mn2＋ such as brightness and duration was improved by the energy transfer from Pr3＋ to Mn2＋ when Pr3＋ ions as sensitizers were doped into matrix. The fact that the TL peak at low temperature was largely enhanced in Mn2＋, Pr3＋ codoped ^-Zn3（PO4）2 phosphor showed the significant increase of defect concentration with suitable depth. There existed two factors working together to be responsible for the enhancement of LLP performance in β-Zn3（PO4）2：Mn2＋,Pr3＋.展开更多
By using inorganic salts as raw materials and citric acid as complexing agent, α-Zn 3(PO 4) 2 and Eu 3+ doped α-Zn 3(PO 4) 2 phosphor powders were prepared by a citrate-gel process. X-ray diffraction (XRD), T...By using inorganic salts as raw materials and citric acid as complexing agent, α-Zn 3(PO 4) 2 and Eu 3+ doped α-Zn 3(PO 4) 2 phosphor powders were prepared by a citrate-gel process. X-ray diffraction (XRD), TG-DTA, FT-IR and luminescence excitation and emission spectra were used to characterize the resulting products. The results of XRD reveal that the powders begin to crystallize at 500 ℃ and pure α-Zn 3(PO 4) 2 phase is obtained at 800 ℃. And the results of XRD reveal that Eu 3+ exists as EuPO 4 in the powder. In the phosphor powders, the Eu 3+ shows its characteristic red-orange (592 nm, 5D 0- 7F 1) emission and has no quenching concentration.展开更多
Luminescence and defect properties of novel phosphor β-Zn 3(PO 4) 2:Zr 4+ were systematically investigated. Corresponding to its lowest optical absorption transition at 240 nm, phosphor emits a bluish-green light...Luminescence and defect properties of novel phosphor β-Zn 3(PO 4) 2:Zr 4+ were systematically investigated. Corresponding to its lowest optical absorption transition at 240 nm, phosphor emits a bluish-green light at 485 nm, which yields the Stokes shift about 20000 cm -1. The unusual optical properties of Zr 4+ ion are ascribed to its uncommon coordination environment. In addition it shows intensive bluish-green long lasting phosphorescence (LLP) due to the existence of electron trap, which is generated by aliovalent substitution of Zr 4+ ion for the cation site in the matrix as shown in thermoluminescence (TL) spectrum.展开更多
KF Zn 3(PO 4) 2 catalyst was found to be effective for isobutane oxidative dehydrogenation into isobutene. The effects of O 2 concentration in feed gas on isobutene yield and selectivity were discussed. The modi...KF Zn 3(PO 4) 2 catalyst was found to be effective for isobutane oxidative dehydrogenation into isobutene. The effects of O 2 concentration in feed gas on isobutene yield and selectivity were discussed. The modification of zinc phosphate by potassium fluoride leads to the formation of a new compound KF Zn 3(PO 4) 2 and surface basic sites, the catalytic performance of which is thus improved.展开更多
TG-DTG technique and Harcourt-Esson integrated equation were used to study the dehydration process of zinc phosphate tetrahydrate α-Zn3（PO4）2·4H2O nanoparticle and its thermal decomposition kinetics. The resul...TG-DTG technique and Harcourt-Esson integrated equation were used to study the dehydration process of zinc phosphate tetrahydrate α-Zn3（PO4）2·4H2O nanoparticle and its thermal decomposition kinetics. The results show that there are three stages of dehydration between 300 and 800 K during the thermal decomposition of α-Zn3（PO4）2·4H2O nanoparticle. The first stage is controlled by chemical reaction with an activation energy of 69.48 kJ·mol^-1 and a pre-exponential factor of 1.77×10^6 s^-1. The second is controlled by nucleation and growth with an activation energy of 78.74 kJ·mol^-1 and a pre-exponential factor of 5.86×10^9 s^-1. The third is controlled by nucleation and growth with an activation energy of 141.5 kJ·mol^-1 and a pre-exponential factor of 1.01×10^12 s^-1. The kinetic compensative effects not only exist in Arrhenius equation but also in Harcourt-Esson equation. Activation energy E is dependent on both the decomposition fraction α and temperature T.展开更多
Using rare earth and zinc coordination polymers with aromatic carboxylic acids as the precursors, composing with the polyethylene glycol (PEG) as the dispersing media, micro crystalline phosphors Zn_3(PO_4)_2∶Eu 3+ a...Using rare earth and zinc coordination polymers with aromatic carboxylic acids as the precursors, composing with the polyethylene glycol (PEG) as the dispersing media, micro crystalline phosphors Zn_3(PO_4)_2∶Eu 3+ and LaPO_4∶Eu 3+ were synthesized by in-situ co-precipitation method. X-ray diffraction and scanning electronic micrograph were used to characterize the resultant samples, whose particle size are in the range of micrometer. The emission spectra of Zn_3(PO_4)_2∶Eu 3+ (λ_ ex=245 nm) and LaPO_4∶Eu 3+ (λ_ ex=390 nm) shows that the emission for Eu 3+ in Zn_3(PO_4)_2 is dominated by the 5D_0→7F_1 (592 nm) magnetic-dipole transition,While the dominant emission for Eu 3+ in LaPO_4 is the typical hypersensitive transition 5D_0→7F_2 (618 nm).展开更多
基金Project supported by the National Natural Science Foundation of China(91222110)Key Project of Industry-University-Research of Science and Technology Department of Fujian Province(2010H6029,2012H6026)+1 种基金Key Project of Advanced Industry of Science and Technology Department of Fujian Province(2013H0053)the Training Program of Fujian Excellent Talents in University
文摘The red long-lasting phosphorescent （LLP） of β-Zn3（POa）2：Mn2＋,pr3＋ material was prepared through combustion and conventional solid-state sintering methods. The influence of Pr3＋ ions on luminescence and LLP of Mn2＋ in 13-Zn3（POa）2：Mn2＋,pr3＋ phosphor was systematically investigated. The phosphor presented a strong photoluminescence peak at 620 nm attributed to the 4T1g→ 6A1 g transition of Mn2＋ ions in octahedral coordination. Red LLP was observed in β-Zn3（PO4）2：Mn2＋,Pr3＋ phosphors with persistence time for more than 2 h. It was found that the long persistent phosphorescent performance of Mn2＋ such as brightness and duration was improved by the energy transfer from Pr3＋ to Mn2＋ when Pr3＋ ions as sensitizers were doped into matrix. The fact that the TL peak at low temperature was largely enhanced in Mn2＋, Pr3＋ codoped ^-Zn3（PO4）2 phosphor showed the significant increase of defect concentration with suitable depth. There existed two factors working together to be responsible for the enhancement of LLP performance in β-Zn3（PO4）2：Mn2＋,Pr3＋.
文摘By using inorganic salts as raw materials and citric acid as complexing agent, α-Zn 3(PO 4) 2 and Eu 3+ doped α-Zn 3(PO 4) 2 phosphor powders were prepared by a citrate-gel process. X-ray diffraction (XRD), TG-DTA, FT-IR and luminescence excitation and emission spectra were used to characterize the resulting products. The results of XRD reveal that the powders begin to crystallize at 500 ℃ and pure α-Zn 3(PO 4) 2 phase is obtained at 800 ℃. And the results of XRD reveal that Eu 3+ exists as EuPO 4 in the powder. In the phosphor powders, the Eu 3+ shows its characteristic red-orange (592 nm, 5D 0- 7F 1) emission and has no quenching concentration.
文摘Luminescence and defect properties of novel phosphor β-Zn 3(PO 4) 2:Zr 4+ were systematically investigated. Corresponding to its lowest optical absorption transition at 240 nm, phosphor emits a bluish-green light at 485 nm, which yields the Stokes shift about 20000 cm -1. The unusual optical properties of Zr 4+ ion are ascribed to its uncommon coordination environment. In addition it shows intensive bluish-green long lasting phosphorescence (LLP) due to the existence of electron trap, which is generated by aliovalent substitution of Zr 4+ ion for the cation site in the matrix as shown in thermoluminescence (TL) spectrum.
文摘KF Zn 3(PO 4) 2 catalyst was found to be effective for isobutane oxidative dehydrogenation into isobutene. The effects of O 2 concentration in feed gas on isobutene yield and selectivity were discussed. The modification of zinc phosphate by potassium fluoride leads to the formation of a new compound KF Zn 3(PO 4) 2 and surface basic sites, the catalytic performance of which is thus improved.
基金Project supported by the National Natural Science Foundation of China （No. 20566003）, and Youth Science Foundation （No. 0339012） of Guangxi, China.
文摘TG-DTG technique and Harcourt-Esson integrated equation were used to study the dehydration process of zinc phosphate tetrahydrate α-Zn3（PO4）2·4H2O nanoparticle and its thermal decomposition kinetics. The results show that there are three stages of dehydration between 300 and 800 K during the thermal decomposition of α-Zn3（PO4）2·4H2O nanoparticle. The first stage is controlled by chemical reaction with an activation energy of 69.48 kJ·mol^-1 and a pre-exponential factor of 1.77×10^6 s^-1. The second is controlled by nucleation and growth with an activation energy of 78.74 kJ·mol^-1 and a pre-exponential factor of 5.86×10^9 s^-1. The third is controlled by nucleation and growth with an activation energy of 141.5 kJ·mol^-1 and a pre-exponential factor of 1.01×10^12 s^-1. The kinetic compensative effects not only exist in Arrhenius equation but also in Harcourt-Esson equation. Activation energy E is dependent on both the decomposition fraction α and temperature T.
文摘Using rare earth and zinc coordination polymers with aromatic carboxylic acids as the precursors, composing with the polyethylene glycol (PEG) as the dispersing media, micro crystalline phosphors Zn_3(PO_4)_2∶Eu 3+ and LaPO_4∶Eu 3+ were synthesized by in-situ co-precipitation method. X-ray diffraction and scanning electronic micrograph were used to characterize the resultant samples, whose particle size are in the range of micrometer. The emission spectra of Zn_3(PO_4)_2∶Eu 3+ (λ_ ex=245 nm) and LaPO_4∶Eu 3+ (λ_ ex=390 nm) shows that the emission for Eu 3+ in Zn_3(PO_4)_2 is dominated by the 5D_0→7F_1 (592 nm) magnetic-dipole transition,While the dominant emission for Eu 3+ in LaPO_4 is the typical hypersensitive transition 5D_0→7F_2 (618 nm).
