A red-emitting phosphor Ca_(2.91)Si_(2)O_(7):0.09Eu^(3+) with partial Al^(3+)/P^(5+) substitution on Si^(4+) was synthesized via a simple solid-state method,and the effects of the introduction of the M^(3+/5+)(M=Al,P)...A red-emitting phosphor Ca_(2.91)Si_(2)O_(7):0.09Eu^(3+) with partial Al^(3+)/P^(5+) substitution on Si^(4+) was synthesized via a simple solid-state method,and the effects of the introduction of the M^(3+/5+)(M=Al,P)ions on the crystal structure and photoluminescence performance of Ca_(2.91)Si_(2−x)M_(x)O_(7):0.09Eu^(3+) phosphors were investigated.The X-ray diffraction(XRD),energy-dispersive X-ray spectroscopy(EDS),and X-ray photoelectron spectroscopy(XPS)results revealed that the structure of Ca_(3)Si_(2)O_(7) remained the same after the introduction of Al^(3+) and P^(5+) ions.The characteristic emission of Eu^(3+)-doped Ca_(3)Si_(2−x)M_(x)O_(7) phosphors exhibited two main peaks at 617 nm(red)and 593 nm(orange)under excitation at 394 nm,which originated from the^(5)D_(0)→^(7)F_(2)and^(5)D_(0)→^(7)F_(1) electron transitions of Eu^(3+) ions.After the partial substitution of Al^(3+) and P^(5+),the red emission intensities of the Ca_(2.91)Si_(2)O_(7):0.09Eu^(3+) phosphors were significantly enhanced by 1.88-and 1.42-fold,respectively,which is attributed to the crystal-field effect around Eu^(3+).Meanwhile,the luminescence intensities of the Ca_(2.91)Si_(1.96)Al_(0.04)O_(7):0.09Eu^(3+) and Ca_(2.91)Si_(1.94)P_(0.06)O_(7):0.09Eu^(3+) phosphors at 210℃ were 79.36%and 77.53%of those at 30°C,respectively,indicating their excellent thermal stability.Moreover,the as-prepared Ca_(2.91)Si_(1.96)Al_(0.04)O_(7):0.09Eu^(3+)and Ca_(2.91)Si_(1.94)P_(0.06)O_(7):0.09Eu^(3+) red-emitting phosphors were combined with a near-ultraviolet chip of 395 nm to fabricate red-light-emitting diode(LED)and white(w)-LED devices with excellent chromaticity features.In summary,Al^(3+)/P^(5+)-substituted Ca_(2.91)Si_(2)O_(7):0.09Eu^(3+) can serve as red-emitting phosphors for applications in w-LEDs.展开更多
The title complex,(μ-pdt)Fe_2(CO)_5(Ph_2PCH_3)(pdt = SCH_2CH_2CH_2S),was obtained by the reaction of the parent complex(μ-pdt)Fe_2(CO)_6 with Ph_2PCH_3 and Me_3NO·2H_2O in good yield(90%). The tit...The title complex,(μ-pdt)Fe_2(CO)_5(Ph_2PCH_3)(pdt = SCH_2CH_2CH_2S),was obtained by the reaction of the parent complex(μ-pdt)Fe_2(CO)_6 with Ph_2PCH_3 and Me_3NO·2H_2O in good yield(90%). The title complex was characterized by IR,~1H NMR,^(31)P{~1H} NMR and ^(13)C{~1H} NMR spectroscopy as well as by single-crystal X-ray diffraction analysis. The molecular structure shows that the title complex contains a butterfly diiron propanedithiolate cluster with five terminal carbonyls and a monophosphine ligand Ph_2PCH_3. The crystal packing diagram reveals that intermolecular C H···O hydrogen bonds between CH_2 and carbonyls,π-π stacking interactions and van der Waals' interactions stabilize the solid state to form a three-dimensional network.展开更多
A series of Dy^(3+)-activated phosphors with the general formula LiGd_(9)(SiO_(4))6-x(GeO_(4))xO_(2):Dy^(3+)(0≤x≤3)characterized by an apatite-type structure were successfully synthesized via a simple solid-state te...A series of Dy^(3+)-activated phosphors with the general formula LiGd_(9)(SiO_(4))6-x(GeO_(4))xO_(2):Dy^(3+)(0≤x≤3)characterized by an apatite-type structure were successfully synthesized via a simple solid-state technique involving a partial substitution of[SiO_(4)]^(4-)with[GeO_(4)]^(4-)species.The effects of homovalent[GeO_(4)]^(4-)-[SiO_(4)]^(4-)substitution on the crystal structure,electronic structure,luminescence properties and thermal performance of LiGd_(9)(SiO_(4))6-x(GeO_(4))xO_(2):Dy^(3+)phosphors were studied in details.The phases and microstructure were performed by using X-ray diffraction(XRD)Rietveld refinement method and scanning electron microscopy(SEM)characterization.The substitution of smaller[SiO_(4)]^(4-)ions by larger[GeO_(4)]^(4-)ones makes their unit cell parameters increase gradually,and their band gaps decrease.The photoluminescence spectra of LiGd_(9)(SiO_(4))6-x(GeO_(4))xO_(2):Dy^(3+)(0≤x≤3)exhibit obvious emission peaks located at 477,573 and 675 nm within a visible wavelength region,resulting in an excellent white light.Furthermore,the I573nm/I477nm values of LiGd_(9)(SiO_(4))6-x(GeO_(4))xO_(2):Dy^(3+)(0≤x≤3)become larger with the partial substitution of[SiO_(4)]^(4-)by[GeO_(4)]^(4-),and their CIE chromaticity coordinates exhibit a yellow shift.展开更多
Anti-structured defects bridge atom migration among heterogeneous sublattices facilitating diffusion but could also result in the collapse of ordered structure.Component distribution Ni(75)AlxV(25-x) alloys are in...Anti-structured defects bridge atom migration among heterogeneous sublattices facilitating diffusion but could also result in the collapse of ordered structure.Component distribution Ni(75)AlxV(25-x) alloys are investigated using a microscopic phase field model to illuminate relations between anti-structured defects and composition,precipitate order,precipitate type,and phase stability.The Ni(75)AlxV(25-x) alloys undergo single Ni3V(stage Ⅰ),dual Ni3Al and Ni3V(stage Ⅱ with Ni3V prior;and stage Ⅲ with Ni3Al prior),and single Ni3Al(stage Ⅳ) with enhanced aluminum level.For Ni3V phase,anti-structured defects(V(Ni1),Niy,except V(Ni2)) and substitution defects(Al(Ni1),Al(Ni2),Alv) exhibit a positive correlation to aluminum in stage I,the positive trend becomes to negative correlation or smooth during stage Ⅱ.For Ni3 Al phase,anti-structured defects(Al(Ni),Ni(Al)) and substitution defects(V(Ni),V(Al)) have a positive correlation to aluminum in stage Ⅱ,but Ni(Al) goes down since stage Ⅲ and lasts to stage Ⅳ.V(Ni) and V(Al) fluctuate when Ni3Al precipitates prior,but go down drastically in stageⅣ.Precipitate type conversion of single Ni3V/dual(Ni3V+Ni3Al) affects Ni3V defects,while dual(Ni3V+Ni3Al)/single Ni3 Al has little effect on Ni3Al defects.Precipitate order swap occurred in the dual phase region affects on Ni3Al defects but not on Ni3V.展开更多
LaMgNi(4-x)Cox(x = 0-0.8) electrode alloys used for MH/Ni batteries were prepared by induction melting. The structures and electrochemical hydrogen storage properties of the alloys were investigated in detail.X-ra...LaMgNi(4-x)Cox(x = 0-0.8) electrode alloys used for MH/Ni batteries were prepared by induction melting. The structures and electrochemical hydrogen storage properties of the alloys were investigated in detail.X-ray diffraction(XRD) and scanning electron microscopy(SEM) analysis show that LaMgNi4 phase and LaNi5 phase are obtained. The lattice parameters of the two phases increase first and then decrease with Co content increasing.The electrochemical properties of the alloy electrodes were measured by means of simulated battery tests. Results show that the addition of Co does not change the discharge voltage plateau of the alloy electrodes. However, the maximum discharge capacity increases from 319.9 mAh·g^-1(x = 0)to 347.5 mAh·g^-1(x = 0.4) and then decreases to331.7 mAh·g^-1(x = 0.8). The effects of Co content on electrochemical kinetics of the alloy electrodes were also performed. The high rate dischargeability(HRD) first increases and then decreases with Co content increasing and reaches the maximum value(95.0 %) when x = 0.4. Test results of the electrochemical impedance spectra(EIS),potentiodynamic polarization curves and constant potential step measurements of the alloy electrodes all demonstrate that when Co content is 0.4 at%, the alloy exhibits the best comprehensive electrochemical properties.展开更多
基金This work was financially supported by the Department of Science and Technology of Sichuan Province(No.2020YJ0157).
文摘A red-emitting phosphor Ca_(2.91)Si_(2)O_(7):0.09Eu^(3+) with partial Al^(3+)/P^(5+) substitution on Si^(4+) was synthesized via a simple solid-state method,and the effects of the introduction of the M^(3+/5+)(M=Al,P)ions on the crystal structure and photoluminescence performance of Ca_(2.91)Si_(2−x)M_(x)O_(7):0.09Eu^(3+) phosphors were investigated.The X-ray diffraction(XRD),energy-dispersive X-ray spectroscopy(EDS),and X-ray photoelectron spectroscopy(XPS)results revealed that the structure of Ca_(3)Si_(2)O_(7) remained the same after the introduction of Al^(3+) and P^(5+) ions.The characteristic emission of Eu^(3+)-doped Ca_(3)Si_(2−x)M_(x)O_(7) phosphors exhibited two main peaks at 617 nm(red)and 593 nm(orange)under excitation at 394 nm,which originated from the^(5)D_(0)→^(7)F_(2)and^(5)D_(0)→^(7)F_(1) electron transitions of Eu^(3+) ions.After the partial substitution of Al^(3+) and P^(5+),the red emission intensities of the Ca_(2.91)Si_(2)O_(7):0.09Eu^(3+) phosphors were significantly enhanced by 1.88-and 1.42-fold,respectively,which is attributed to the crystal-field effect around Eu^(3+).Meanwhile,the luminescence intensities of the Ca_(2.91)Si_(1.96)Al_(0.04)O_(7):0.09Eu^(3+) and Ca_(2.91)Si_(1.94)P_(0.06)O_(7):0.09Eu^(3+) phosphors at 210℃ were 79.36%and 77.53%of those at 30°C,respectively,indicating their excellent thermal stability.Moreover,the as-prepared Ca_(2.91)Si_(1.96)Al_(0.04)O_(7):0.09Eu^(3+)and Ca_(2.91)Si_(1.94)P_(0.06)O_(7):0.09Eu^(3+) red-emitting phosphors were combined with a near-ultraviolet chip of 395 nm to fabricate red-light-emitting diode(LED)and white(w)-LED devices with excellent chromaticity features.In summary,Al^(3+)/P^(5+)-substituted Ca_(2.91)Si_(2)O_(7):0.09Eu^(3+) can serve as red-emitting phosphors for applications in w-LEDs.
基金Supported by the Natural Science Foundation of Zhejiang Province(No.LY16B020009)K.C.Wong Education Foundation
文摘The title complex,(μ-pdt)Fe_2(CO)_5(Ph_2PCH_3)(pdt = SCH_2CH_2CH_2S),was obtained by the reaction of the parent complex(μ-pdt)Fe_2(CO)_6 with Ph_2PCH_3 and Me_3NO·2H_2O in good yield(90%). The title complex was characterized by IR,~1H NMR,^(31)P{~1H} NMR and ^(13)C{~1H} NMR spectroscopy as well as by single-crystal X-ray diffraction analysis. The molecular structure shows that the title complex contains a butterfly diiron propanedithiolate cluster with five terminal carbonyls and a monophosphine ligand Ph_2PCH_3. The crystal packing diagram reveals that intermolecular C H···O hydrogen bonds between CH_2 and carbonyls,π-π stacking interactions and van der Waals' interactions stabilize the solid state to form a three-dimensional network.
基金supported by the Guangdong Basic and Applied Basic Research Foundation(2021A1515110283,2021A1515110702)the China Postdoctoral Science Foundation(2021M702562)+4 种基金the Research Start-up Funds of DGUT(211135307)the National Natural Science Foundation of China(51872269)the Key Scientific Research Project in Colleges and Universities of Henan Province of China(21A430040)the Natural Science Foundation of Guangdong Province(2018B030311022)Guangdong Innovation Research Team for Higher Education(2017KCXTD030)。
文摘A series of Dy^(3+)-activated phosphors with the general formula LiGd_(9)(SiO_(4))6-x(GeO_(4))xO_(2):Dy^(3+)(0≤x≤3)characterized by an apatite-type structure were successfully synthesized via a simple solid-state technique involving a partial substitution of[SiO_(4)]^(4-)with[GeO_(4)]^(4-)species.The effects of homovalent[GeO_(4)]^(4-)-[SiO_(4)]^(4-)substitution on the crystal structure,electronic structure,luminescence properties and thermal performance of LiGd_(9)(SiO_(4))6-x(GeO_(4))xO_(2):Dy^(3+)phosphors were studied in details.The phases and microstructure were performed by using X-ray diffraction(XRD)Rietveld refinement method and scanning electron microscopy(SEM)characterization.The substitution of smaller[SiO_(4)]^(4-)ions by larger[GeO_(4)]^(4-)ones makes their unit cell parameters increase gradually,and their band gaps decrease.The photoluminescence spectra of LiGd_(9)(SiO_(4))6-x(GeO_(4))xO_(2):Dy^(3+)(0≤x≤3)exhibit obvious emission peaks located at 477,573 and 675 nm within a visible wavelength region,resulting in an excellent white light.Furthermore,the I573nm/I477nm values of LiGd_(9)(SiO_(4))6-x(GeO_(4))xO_(2):Dy^(3+)(0≤x≤3)become larger with the partial substitution of[SiO_(4)]^(4-)by[GeO_(4)]^(4-),and their CIE chromaticity coordinates exhibit a yellow shift.
基金Project supported by the Natural Science Basic Research Plan in Shaanxi Province of China(Grant No.2016JQ5014)the Fundamental Research Funds for the Central Universities,China(Grant No.3102014JCQ01024)+2 种基金the Research Fund of the State Key Laboratory of Solidification Processing(NWPU),China(Grant No.114-QP-2014)the Specialized Research Fund for the Doctoral Program of Higher Education of China(Grant No.20136102120021)the National Natural Science Foundation of China(Grant Nos.51474716 and 51475378)
文摘Anti-structured defects bridge atom migration among heterogeneous sublattices facilitating diffusion but could also result in the collapse of ordered structure.Component distribution Ni(75)AlxV(25-x) alloys are investigated using a microscopic phase field model to illuminate relations between anti-structured defects and composition,precipitate order,precipitate type,and phase stability.The Ni(75)AlxV(25-x) alloys undergo single Ni3V(stage Ⅰ),dual Ni3Al and Ni3V(stage Ⅱ with Ni3V prior;and stage Ⅲ with Ni3Al prior),and single Ni3Al(stage Ⅳ) with enhanced aluminum level.For Ni3V phase,anti-structured defects(V(Ni1),Niy,except V(Ni2)) and substitution defects(Al(Ni1),Al(Ni2),Alv) exhibit a positive correlation to aluminum in stage I,the positive trend becomes to negative correlation or smooth during stage Ⅱ.For Ni3 Al phase,anti-structured defects(Al(Ni),Ni(Al)) and substitution defects(V(Ni),V(Al)) have a positive correlation to aluminum in stage Ⅱ,but Ni(Al) goes down since stage Ⅲ and lasts to stage Ⅳ.V(Ni) and V(Al) fluctuate when Ni3Al precipitates prior,but go down drastically in stageⅣ.Precipitate type conversion of single Ni3V/dual(Ni3V+Ni3Al) affects Ni3V defects,while dual(Ni3V+Ni3Al)/single Ni3 Al has little effect on Ni3Al defects.Precipitate order swap occurred in the dual phase region affects on Ni3Al defects but not on Ni3V.
基金financially supported by the National Natural Science Foundations of China (Nos.51161015,51371094 and 51471054)
文摘LaMgNi(4-x)Cox(x = 0-0.8) electrode alloys used for MH/Ni batteries were prepared by induction melting. The structures and electrochemical hydrogen storage properties of the alloys were investigated in detail.X-ray diffraction(XRD) and scanning electron microscopy(SEM) analysis show that LaMgNi4 phase and LaNi5 phase are obtained. The lattice parameters of the two phases increase first and then decrease with Co content increasing.The electrochemical properties of the alloy electrodes were measured by means of simulated battery tests. Results show that the addition of Co does not change the discharge voltage plateau of the alloy electrodes. However, the maximum discharge capacity increases from 319.9 mAh·g^-1(x = 0)to 347.5 mAh·g^-1(x = 0.4) and then decreases to331.7 mAh·g^-1(x = 0.8). The effects of Co content on electrochemical kinetics of the alloy electrodes were also performed. The high rate dischargeability(HRD) first increases and then decreases with Co content increasing and reaches the maximum value(95.0 %) when x = 0.4. Test results of the electrochemical impedance spectra(EIS),potentiodynamic polarization curves and constant potential step measurements of the alloy electrodes all demonstrate that when Co content is 0.4 at%, the alloy exhibits the best comprehensive electrochemical properties.