Nanophosphor with the nominal composition of Ca0.8 Zn0.2 TiO3 ： Pr3 ＋ , Na^＋ （CZTOPN） was synthesized at relatively low temperature by the sol-gel method. Metal ions were dispersed by citric acid in ethylene glyc...Nanophosphor with the nominal composition of Ca0.8 Zn0.2 TiO3 ： Pr3 ＋ , Na^＋ （CZTOPN） was synthesized at relatively low temperature by the sol-gel method. Metal ions were dispersed by citric acid in ethylene glycol solvent and then react with Ti（OC4H9）4 to form sol and gel. The decomposition process of the precursor, and crystallization and particle size of CZTOPN were examined by thermal analysis （TG-DSC）, powder X-ray diffraction （XRD）, and scan election microscopy （SEM）. Results of TG-DSC and XRD reveal that the composition of Ca0.8 Zn0.2 TiO3 ： Pr3 ＋ , Na^＋ changes with the sintering temperature. SEM data indicate that the diameter of particles is under 50 nm even if the sintering temperature increases to 1000 ℃. In contrast to a solid state reaction, the excitation spectra of samples synthesized by the sol-gel method shift blue about 10 nm and the emission intensity at 617 nm increases significantly.展开更多
A type of red luminescent Sr3Al2O6：Eu2＋, Dy3＋ phosphor powder is synthesised by sol-gel-combustion processing, with metal nitrates used as the source of metal ions and citric acid as a chelating agent of metal ions...A type of red luminescent Sr3Al2O6：Eu2＋, Dy3＋ phosphor powder is synthesised by sol-gel-combustion processing, with metal nitrates used as the source of metal ions and citric acid as a chelating agent of metal ions. By tracing the formation process of the sol-gel, it is found that it is necessary to reduce the amount of NO3 by dropping ethanol into the solution for forming a stable and homogeneous sol-gel. Thermogravimetric and Differential Scanning Calorimeter Analysis, x-ray diffractionmeter, scanning electron microscopy and photoluminescence spectroscopy are used to investigate the luminescent properties of the as-synthesised Sr3A1206：Eu2＋, Dy3＋. The results reveal that the Sr3Al2O6 crystallises completely when the combustion ash is sintered at 1250℃. The excitation and the emission spectra indicate that the excitation broadband lies mainly in a visible range and the phosphors emit a strong light at 618 nm under the excitation of 472 nm. The afterglow of （Sr0.94Eu0.03Dy0.03）3Al2O6 phosphors sintered at 1250℃ lasts for over 1000 s when the excited source is cut off.展开更多
The SrTiO3 ： Pr^3＋ material, co-doped with monovalent Li^＋ , divalent Mg^2＋ , and trivalent Al^3＋ was prepared by a new sol-gel method. The phase and crystallinity of the synthesized materials were investigated b...The SrTiO3 ： Pr^3＋ material, co-doped with monovalent Li^＋ , divalent Mg^2＋ , and trivalent Al^3＋ was prepared by a new sol-gel method. The phase and crystallinity of the synthesized materials were investigated by powder X-ray diffraction（XRD） and scanning electron microcopy（SEM）. Among the co-doped ion, Al^3＋ incorporation caused the least lattice change and had the best crystallinity. Photoluminescence spectra were taken to investigate the luminescence characteristics. We observed a red luminescence change of SrTiO3 ： Pr^3＋ after being co-doped, and a best enhancement on the red luminescence with the trivalent Al^3＋ was observed. The present results indicated that the charge defect associated with Al^3＋ has led to charge compensation of Pr^＋ and also implied that the charge defects（usually the second dopant ions replacing the A or B sites in the lattice） which are closer to PrSr^＋ contribute more to the red luminescence enhancement.展开更多
The efficient new red emitting scheelite-type compounds, Eu3＋-doped （5 tool.%） Y（Zro.5Wo.5）O4, Lu（Zro.sWo,5）O4 and Y（Y1/3W2/3）O4, were successfully prepared. The crystal structure, photoluminescence and decay...The efficient new red emitting scheelite-type compounds, Eu3＋-doped （5 tool.%） Y（Zro.5Wo.5）O4, Lu（Zro.sWo,5）O4 and Y（Y1/3W2/3）O4, were successfully prepared. The crystal structure, photoluminescence and decay properties of the obtained phosphors were investigated. Shifts of the peaks in the XRD patterns were observed when y3＋ sites in the host were occupied by Lu3＋ or Zr/W sites were occupied by Y/W, As a result of the crystallographic occupancy of Eu3＋ located at the cation positions without inversion symmetry, under O---Zr/W and O---.Eu3＋ ligand-to-metal charge-transfer states （LMCT） excitation at 300 nm, the emission spectra of these compounds presented 5Do---7F2 transition for EH3＋ at 612 nm. The diagram of EU3＋ energy levels in these new scheelite-type compounds and the energy transfer processes were discussed.展开更多
Fabrication of efficient solid luminogens with tunable emission is both fundamentally significant and technically important. Herein, based on our previous strategy for the construction of efficient and multifunctional...Fabrication of efficient solid luminogens with tunable emission is both fundamentally significant and technically important. Herein, based on our previous strategy for the construction of efficient and multifunctional solid luminogens through the combination of diverse aggregation-induced emission （ALE） units with other functional moieties, a group of luminophores with electron donor-acceptor （D-A） structure and typical intramolecular charge transfer （ICT） characteristics, namely CZ-DCDPP, DPA-DCDPP and DBPA-DCDPP were synthesized and investigated. The presence of twisting and AlE-active 2,3- dicyano-S,6-diphenylpyrazine （DCDPP） moiety endows them highly emissive in the solid states, whereas the introduction of arylamines with varied electron-donating capacity and different conjugation render them with tunable solid emissions from green to red. While CZ-DCDPP and DPA-DCDPP solids exhibit distinct mechanochromism, both DPA-DCDPP and DBPA-DCDPP solids can generate efficient red emission. Owing to their high efficiency, remarkable thermal and morphological stabilities and moreover red emission, they are promising for diverse optoelectronic and biological applications.展开更多
文摘Nanophosphor with the nominal composition of Ca0.8 Zn0.2 TiO3 ： Pr3 ＋ , Na^＋ （CZTOPN） was synthesized at relatively low temperature by the sol-gel method. Metal ions were dispersed by citric acid in ethylene glycol solvent and then react with Ti（OC4H9）4 to form sol and gel. The decomposition process of the precursor, and crystallization and particle size of CZTOPN were examined by thermal analysis （TG-DSC）, powder X-ray diffraction （XRD）, and scan election microscopy （SEM）. Results of TG-DSC and XRD reveal that the composition of Ca0.8 Zn0.2 TiO3 ： Pr3 ＋ , Na^＋ changes with the sintering temperature. SEM data indicate that the diameter of particles is under 50 nm even if the sintering temperature increases to 1000 ℃. In contrast to a solid state reaction, the excitation spectra of samples synthesized by the sol-gel method shift blue about 10 nm and the emission intensity at 617 nm increases significantly.
基金Project supported by the Key Research Project of Science and Technology of Shanxi, Shanxi Province, China (Grant No 2007031141)the Natural Science Foundation of Shanxi Province, China (Grant No 2007011061)the Scientific Research Foundation of the Higher Education Institutions of Shanxi Province, China (Grant No 20080012)
文摘A type of red luminescent Sr3Al2O6：Eu2＋, Dy3＋ phosphor powder is synthesised by sol-gel-combustion processing, with metal nitrates used as the source of metal ions and citric acid as a chelating agent of metal ions. By tracing the formation process of the sol-gel, it is found that it is necessary to reduce the amount of NO3 by dropping ethanol into the solution for forming a stable and homogeneous sol-gel. Thermogravimetric and Differential Scanning Calorimeter Analysis, x-ray diffractionmeter, scanning electron microscopy and photoluminescence spectroscopy are used to investigate the luminescent properties of the as-synthesised Sr3A1206：Eu2＋, Dy3＋. The results reveal that the Sr3Al2O6 crystallises completely when the combustion ash is sintered at 1250℃. The excitation and the emission spectra indicate that the excitation broadband lies mainly in a visible range and the phosphors emit a strong light at 618 nm under the excitation of 472 nm. The afterglow of （Sr0.94Eu0.03Dy0.03）3Al2O6 phosphors sintered at 1250℃ lasts for over 1000 s when the excited source is cut off.
基金The Natural Science Foundation of Shaan'xi Province(2005F06)
文摘The SrTiO3 ： Pr^3＋ material, co-doped with monovalent Li^＋ , divalent Mg^2＋ , and trivalent Al^3＋ was prepared by a new sol-gel method. The phase and crystallinity of the synthesized materials were investigated by powder X-ray diffraction（XRD） and scanning electron microcopy（SEM）. Among the co-doped ion, Al^3＋ incorporation caused the least lattice change and had the best crystallinity. Photoluminescence spectra were taken to investigate the luminescence characteristics. We observed a red luminescence change of SrTiO3 ： Pr^3＋ after being co-doped, and a best enhancement on the red luminescence with the trivalent Al^3＋ was observed. The present results indicated that the charge defect associated with Al^3＋ has led to charge compensation of Pr^＋ and also implied that the charge defects（usually the second dopant ions replacing the A or B sites in the lattice） which are closer to PrSr^＋ contribute more to the red luminescence enhancement.
基金financially supported by the National Natural Science Foundation of China(12074324 and 11374247)the Science,Technology,and Innovation Commission of Shenzhen Municipality(JCJY20180508163404043 and JCYJ20170818141709893)。
基金supported by National Natural Science Foundation of China(11104298U133220251302039)
文摘The efficient new red emitting scheelite-type compounds, Eu3＋-doped （5 tool.%） Y（Zro.5Wo.5）O4, Lu（Zro.sWo,5）O4 and Y（Y1/3W2/3）O4, were successfully prepared. The crystal structure, photoluminescence and decay properties of the obtained phosphors were investigated. Shifts of the peaks in the XRD patterns were observed when y3＋ sites in the host were occupied by Lu3＋ or Zr/W sites were occupied by Y/W, As a result of the crystallographic occupancy of Eu3＋ located at the cation positions without inversion symmetry, under O---Zr/W and O---.Eu3＋ ligand-to-metal charge-transfer states （LMCT） excitation at 300 nm, the emission spectra of these compounds presented 5Do---7F2 transition for EH3＋ at 612 nm. The diagram of EU3＋ energy levels in these new scheelite-type compounds and the energy transfer processes were discussed.
基金supported by the National Key Research and Development Program of China(2021YFE0105700)the National Natural Science Foundations of China(51972118)+3 种基金the Natural Science Foundation of Shandong Province(ZR2021ZD10 and ZR2018JL016)Guangzhou Science&Technology Project(202007020005)the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(2017BT01X137)funded by Russian Foundation for Basic Research(19-52-80003)。
基金supported by the National Natural Science Foundation of China (No. 51473092)the Shanghai Rising-Star Program (No. 15QA1402500)
文摘Fabrication of efficient solid luminogens with tunable emission is both fundamentally significant and technically important. Herein, based on our previous strategy for the construction of efficient and multifunctional solid luminogens through the combination of diverse aggregation-induced emission （ALE） units with other functional moieties, a group of luminophores with electron donor-acceptor （D-A） structure and typical intramolecular charge transfer （ICT） characteristics, namely CZ-DCDPP, DPA-DCDPP and DBPA-DCDPP were synthesized and investigated. The presence of twisting and AlE-active 2,3- dicyano-S,6-diphenylpyrazine （DCDPP） moiety endows them highly emissive in the solid states, whereas the introduction of arylamines with varied electron-donating capacity and different conjugation render them with tunable solid emissions from green to red. While CZ-DCDPP and DPA-DCDPP solids exhibit distinct mechanochromism, both DPA-DCDPP and DBPA-DCDPP solids can generate efficient red emission. Owing to their high efficiency, remarkable thermal and morphological stabilities and moreover red emission, they are promising for diverse optoelectronic and biological applications.
