LiFe0.99RE0.01PO4/C cathode material was synthesized by solid-state reaction method using FeC2O4-2H2O, Li2CO3, NH4H2PO4, RE（NO3）3·nH2O as raw materials and glucose as a carbon source. The doping effects of rare...LiFe0.99RE0.01PO4/C cathode material was synthesized by solid-state reaction method using FeC2O4-2H2O, Li2CO3, NH4H2PO4, RE（NO3）3·nH2O as raw materials and glucose as a carbon source. The doping effects of rare earth ions, such as La3＋, Ce3＋, Nd3＋, on the structure and electrochemical properties of LiFePO4/C cathode material were systematically investigated. The as-prepared samples were characterized by means of X-ray diffraction （XRD）, scanning electron microscopy （SEM） and particle size analysis. The electrochemical properties were investigated in terms of constant-current charge/discharge cycling tests. The XRD results showed that the rare earth ions doping did not change the olivine structure of LiFePO4, and all the doped samples were of single-phase with high crystallinity. SEM and particle size analysis results showed that the doping of La3＋, Ce3＋ and Nds＋ led to the decrease of particle size. The electrochemical results exhibited that the doping of La3＋ and Ce3＋ could improve the high-rate capability of LiFePO4/C cathode material, among which, the material doped with 1% Ce3＋ exhibited the optimal electrochemical properties, whose specific discharge capacities could reach 128.9, 119.5 and 104.4 mAh/g at 1C, 2C and 5C rates, respectively.展开更多
Polyanion-based materials are considered one of the most attractive and promising cathode materials for lithiumion batteries(LIBs)due to their good stability,safety,cost-effectiveness,suitable voltages,and minimal env...Polyanion-based materials are considered one of the most attractive and promising cathode materials for lithiumion batteries(LIBs)due to their good stability,safety,cost-effectiveness,suitable voltages,and minimal environmental impact.However,these materials suffer from poor rate capability and low-temperature performance owing to limited electronic and ionic conductivity,which restricts their practical applicability.Recent developments,such as coating material particles with carbon or a conductive polymer,crystal deformation through the doping of foreign metal ions,and the production of nanostructured materials,have significantly enhanced the electrochemical performances of these materials.The successful applications of polyanion-based materials,especially in lithium-ion batteries,have been extensively reported.This comprehensive review discusses the current progress in crystal deformation in polyanion-based cathode materials,including phosphates,fluorophosphates,pyrophosphates,borates,silicates,sulfates,fluorosilicates,and oxalates.Therefore,this review provides detailed discussions on their synthesis strategies,electrochemical performance,and the doping of various ions.展开更多
Ultrathin TiO_(2)nanosheets with coexposed{001}/{101}facets have attracted considerable attention because of their high photocatalytic activity.However,the charge-separated states in the TiO_(2)nanosheets must be exte...Ultrathin TiO_(2)nanosheets with coexposed{001}/{101}facets have attracted considerable attention because of their high photocatalytic activity.However,the charge-separated states in the TiO_(2)nanosheets must be extended to further enhance their photocatalytic activity for H_(2)evolution.Herein,we present a successful attempt to selectively dope lanthanide ions into the{101}facets of ultrathin TiO_(2)nanosheets with coexposed{001}/{101}facets through a facile one-step solvothermal method.The lanthanide doping slightly extended the light-harvesting region and markedly improved the charge-separated states of the TiO_(2)nanosheets as evidenced by UV-vis absorption and steady-state/transient photoluminescence spectra.Upon simulated sunlight irradiation,we observed a 4.2-fold enhancement in the photocatalytic H_(2)evolution activity of optimal Yb^(3+)-doped TiO_(2)nanosheets compared to that of their undoped counterparts.Furthermore,when Pt nanoparticles were used as cocatalysts to reduce the H_(2)overpotential in this system,the photocatalytic activity enhancement factor increased to 8.5.By combining these results with those of control experiments,we confirmed that the extended charge-separated states play the main role in the enhancement of the photocatalytic H_(2)evolution activity of lanthanide-doped TiO_(2)nanosheets with coexposed{001}/{101}facets.展开更多
In this study, nanosized TiO2 co-doped with Fe3+ and Nd3+ ions was synthesized via a sol-gel method. The metallic ion doped TiO2 was thoroughly characterized with XRD and UV-vis, and the photocatalytic activity was ev...In this study, nanosized TiO2 co-doped with Fe3+ and Nd3+ ions was synthesized via a sol-gel method. The metallic ion doped TiO2 was thoroughly characterized with XRD and UV-vis, and the photocatalytic activity was evaluated by degrading methylene blue (MB) solution. The results indicated that TiO2 crystalline size was reduced and phase transformation of anatase to rutile was suppressed as the content of doped Nd3+ ion increased in the co-doped TiO2. The UV-vis spectra of co-doped TiO2 seemed to simply overlay two spectra of single metal doped TiO2, and had significantly increased absorbance in the ranges of 400～500 nm, 565～600 nm and 730～765 nm as compared to pure TiO2. The photocatalytic activity of co-doped TiO2 was obviously enhanced, and raised about 30% compared to that of pure TiO2 as doped Nd3+ content was 0.15% and Fe3+ content was 0.05%, respectively. The enhanced catalytic activity was attributed to a synergistic effect of two doped ions, where doped Fe3+ ion inhibited the recombination of photogenerated electron and hole, and Nd3+ ion brought more surface carboxyl to promote the degradation reaction.展开更多
Ca1-xRxCu3Ti4O12(R=La,Y,Gd;x=0,0.1,0.2,0.3) electronic ceramics were fabricated by conventional solid-state reaction method.The microstructure and dielectric properties as well as impedance behavior were carefully inv...Ca1-xRxCu3Ti4O12(R=La,Y,Gd;x=0,0.1,0.2,0.3) electronic ceramics were fabricated by conventional solid-state reaction method.The microstructure and dielectric properties as well as impedance behavior were carefully investigated.XRD results showed that the secondary phases with the general formula R2Ti2O7 existed at grain boundaries of rare earth doped ceramics,which inhibited abnormal grain growth.The dielectric constant decreased from 4×105 in pure CaCu3Ti4O12(CCTO) ceramics to 2×103 with rare earth doping....展开更多
The doping effects of La^3＋, Gd^3＋ and Lu^3＋ on the crystal structure and luminescence properties of （Yo96-x LnxCe0.04）3Al5O12（Ln = Gd, La, Lu） phosphors were studied. The X-ray diffraction patterns presented t...The doping effects of La^3＋, Gd^3＋ and Lu^3＋ on the crystal structure and luminescence properties of （Yo96-x LnxCe0.04）3Al5O12（Ln = Gd, La, Lu） phosphors were studied. The X-ray diffraction patterns presented that with the inerease of the doping concentrations of La^3＋ and Gd^3＋ ions, the d-value of （Y0.96-xLnxCe0.04）3Al5O12 （Ln = Gd, La） inereased and the larger the doping ion, the stronger the effect would be. The doping amount causing phase transition in （Y0.96-xLnxCe0.04）3Al5O12 decreased with the inerease of the ionic radii of the doping lanthanide ions （La^3＋： 0.106 nm, Gd^3＋： 0. 094 nm, Lu^3＋ ： 0.083 nm）. The bigger doping ion of Gd^3＋ made the emission of （Y0.96-xGdxCe0.04）3Al5O12 move to red spectral region, but the smaller one of Lu^3＋ made it blue.展开更多
In this study,K+-doped γ-Ce2 S3 was successfully prepared via a gas-solid reaction method using CeO2,K2 CO3,and CS2 as raw materials.The effects of the suitable sulfide system and different molar ratios of K to Ce(nK...In this study,K+-doped γ-Ce2 S3 was successfully prepared via a gas-solid reaction method using CeO2,K2 CO3,and CS2 as raw materials.The effects of the suitable sulfide system and different molar ratios of K to Ce(nK/Ce=0-0.30) on the phase composition,crystal structure,chromaticity and thermal stability ofγ-Ce2 S3 were systematically investigated.Pure γ-Ce2 S3 was obtained by calcining the doped samples at840℃ for 150 min.After calcination at the same temperature the undoped K+samples exhibit a pure α-phase.Samples with a K/Ce molar ratio(nK/Ce) of 0.10-0.25 comprise only the γ-phase;and when nK/Ce exceeds 0.25,a new heterogeneous phase,KCeS2,emerges.For values of nK/Ce in the range of0-0.25,the γ-Ce2 S3 lattice parameters gradually increases with increasing K+ content.When nK/Ceexceedes 0.25,the lattice parameters remains unchanged.As nK/Ce increased,the synthesized color gradually changes from red to orange—red and finally,to yellow.The redness value a* reaches the maximum(L*=33.86,a*=36.68,b*=38.15) when nK/Ce=0.10,The nK/Ce=0.10 composition continues to exhibit the y-phase after heat treatment at 420℃ for 10 min in air.The K+doping fills the internal vacancies of γ-Ce2 S3 and formed a solid solution,which is beneficial for the stability of its lattice,thus improving the thermal stability of γ-Ce2 S3(from 350 to 420℃).展开更多
In this work,a series of self-activated KYb(MoO_(4))_(2) phosphors with various x at% Er^(3+) doping concentrations(x=0.5,1,3,5,8,10,15) was synthesized by the solid-state reaction method.The phase structure of the as...In this work,a series of self-activated KYb(MoO_(4))_(2) phosphors with various x at% Er^(3+) doping concentrations(x=0.5,1,3,5,8,10,15) was synthesized by the solid-state reaction method.The phase structure of the as-prepared samples was analyzed by X-ray diffraction(XRD),XRD Rietveld refinement and Fourier transform infrared(FT-IR) spectroscopy.The as-prepared samples retain the orthorhombic structure with space group of Pbcn even Er^(3+) doping concentration up to 15 at%.High-purity upconversion(UC) green emission with green to red intensity ratio of 55 is observed from the as-prepared samples upon the excitation of 980 nm semiconductor laser and the optimum doping concentration of Er^(3+) ions in the self-activated KYb(MoO_(4))_(2) host is revealed as 3 at%.The strong green UC emission is confirmed as a two-photon process based on the power-dependent UC spectra.In addition,the fluorescence intensity ratios(FIRs) of the two thermally-coupled energy levels,namely ^(2)H_(11/2) and ^(4)S_(3/2).of Er^(3+) ions were investigated in the temperature region 300-570 K to evaluate the optical temperature sensor behavior of the sample.The maximum relative sensitivity(S_(R)) is determined to be 0.0069 K^(-1) at300 K and the absolute sensitivity(S_(A)) is determined to be 0.0126 K^(-1) at 300 K.The S_(A) of self-activated KYb(MoO_(4))2:Er^(3+)is almost twice that of traditional KY(MoO_(4))2:Er^(3+)/Yb^(3+)codoping phosphor.The results demonstrate that Er^(3+) ions doped self-activated KYb(MoO_(4))2 phosphor has promising application in visible display,trademark security and optical temperature sensors.展开更多
The electronic state density and energy bands of Ag-doped anatase TiO2 are studied by WIEN2k software package based on DFT. The calculation results show that the band-gap of anatase titania became bigger after doping ...The electronic state density and energy bands of Ag-doped anatase TiO2 are studied by WIEN2k software package based on DFT. The calculation results show that the band-gap of anatase titania became bigger after doping with Ag metal ions. The band-gap transfers from 2.04 to 2.5 eV, but a new energy band appears among the forbidden band after the Ag atom substitution. The interband width of Ag-TiO2 is 0.17 eV, which is located at –0.07 eV; more excitation and jump routes are opened for the electrons. The lowest excitation energy can achieve 1.2 eV, which may allow the photons with lower energy （at longer wavelength, such as visible light） to be absorbed. Ag ions are implanted into the titania nanotube sample by MEVVA （Metal Vapor Vacuum Arc） implanter. The photo-electrochemical response and photo-degradation experiment of titania nanotube samples implanted with Ag ions are tested under UV and visible light; the results indicated that the performance of implanted titania naotubes is enhanced both under UV and visible light; it is worth mentioning that the photocurrent density can reach 0.145 mA/cm2 under visible light, which is 181 times higher than those of pure TiNT, and the k value of degradation methyl orange can obtain 0.30 h-1, which is 71 times higher than that of pure TiNT. All the experimental results are consistent well with the theoretic ones.展开更多
Microporous titanium dioxide thin films have been fabricated on titanium plates by the micro-plasma oxidation method with the electrolyte of Na3PO4+Na2B4O7.The influence of V5+ions addition in the electrolyte on the p...Microporous titanium dioxide thin films have been fabricated on titanium plates by the micro-plasma oxidation method with the electrolyte of Na3PO4+Na2B4O7.The influence of V5+ions addition in the electrolyte on the photocatalytic activities was investigated.A kind of typical textile industry pollutant(methylene blue)was used to evaluate the photo-catalytic activity of the films.The results showed that this activity of the films had been improved by adding V5+ions into the electrolyte solution.The removal of methylene blue reaches 90%for 60 min when V5+ions addition concentrate is 0.3 g/L.X-ray diffraction,scanning electron microscopy and atomic force microscopy techniques were applied to characterize the modified films.Experimental results show that the improvement in activity was related to the forming of titanium dioxide lattice distortion,which could accept more photoexcitated holes and produce more strong surface free radicals to oxidate adsorptive molecules.展开更多
It is a difficult challenge to simultaneously employ the cationic and anionic redox chemistry in cathode materials for sodium-ion batteries with high energy.Even though layered oxides(classified as two-dimensional oxi...It is a difficult challenge to simultaneously employ the cationic and anionic redox chemistry in cathode materials for sodium-ion batteries with high energy.Even though layered oxides(classified as two-dimensional oxides)demonstrate excellent promise in the high discharge capacity,their poor oxygen transformation via redox reactions is limited by crystal instability.Therefore,a doping strategy was conceived to tackle this issue and increase redox efficiency.K doping was applied to transform the two-dimensional Na_(1.3)Mn_(0.7)O_(2)(NMO)to threedimensional K_(0.2)Na_(1.3)Mn_(0.5)O_(2)(KNMO),preventing the irreversible phase shift and preserving the crystal structure’s stability while cycling.With this modification treatment,KNMO features manganese and oxygen reactive sites,delivering a promising energy density of 190mAh·g^(-1)at 5 mA·g^(-1)in the 2.0–4.5 V voltage range(vs71.4 mAh·g^(-1)for the pristine NMO).Moreover,it displays improved capacity retention of more than 83.5%after 50cycles at 50 mA·g^(-1).The results demonstrated that doped intercalation oxides were promising for redox oxygen transformation in sodium-ion batteries.展开更多
The rare earth ion Yb^3+ doped Bi2WO6 photocatalysts were synthesized by hydrothermal method.Moreover,XRD,XPS,FESEM,TEM,Ramam,N2 adsorption-desorption isotherm measurements and UV-vis diffusion reflectance spectra wer...The rare earth ion Yb^3+ doped Bi2WO6 photocatalysts were synthesized by hydrothermal method.Moreover,XRD,XPS,FESEM,TEM,Ramam,N2 adsorption-desorption isotherm measurements and UV-vis diffusion reflectance spectra were used to characterize the Yb^3+ doped Bi2WO6 photocatalysts.The morphology,specific surface area,and pore volume distribution were greatly affected after Yb3+ ions doping.Photocatalytic performance of Bi2WO6 was effectively enhanced after Yb3+ ions doping,6% Yb^3+ doped Bi2WO6 had the best photocatalytic performance,and 96.2% Rhodamine B was degradated after irradiated 30 min,which was 1.29 times that of the pristine one.The enhanced photocatalytic performance was due to the increased specific surface area,decreased energy band gap and inhibition of photoelectron-hole recombination after Yb3+ ions doping.展开更多
Sulfur dioxide(SO_(2))emissions from diesel exhaust pose a serious threat to the environment and human health.Thus,desulfurization technology and the performance of desulfurization materials must be improved.In this s...Sulfur dioxide(SO_(2))emissions from diesel exhaust pose a serious threat to the environment and human health.Thus,desulfurization technology and the performance of desulfurization materials must be improved.In this study,MnO_(2) was modified with various alkali metal ions using the impregnation method to enhance its SO_(2) capture performance.The composites were characterized intensively by scanning electron microscopy,energydispersive X-ray spectroscopy,X-ray diffraction spectroscopy,and Brunauer-Emmett-Teller theory.The SO_(2) capture performance of these composites were measured via thermogravimetry,and the effect of doping with alkali metal ions on the SO_(2) capture performance of MnO_(2) was investigated.Results showed that the SO_(2) capture performance of MnO_(2) could be enhanced by doping with alkali metal ions,and the MnO_(2) composite doped with LiOH(2.0 mol/L)had the best SO_(2) capture capacity(124 mgSO_(2)/gMaterial),which was 18%higher than that of pure MnO_(2).Moreover,the type and concentration of alkali metal ions had varying effects on the SO_(2) capture performance of MnO_(2).In our experiment,the SO_(2) capture performance of the MnO_(2) doped with NaOH,LiCl,Na2CO3,K2CO3,and Li2CO3 composites were worse than that of pure MnO_(2).Therefore,the influences of the type and concentration of alkali metal ions to be doped into desulfurization materials must be considered comprehensively.展开更多
The zero-dimensional(0D)ordered lead-free double perovskites(DPs)Cs_(2)B^((IV))X_(6)have recently been recognized as promising candidates in the optoelectronics domain.Their exceptional stability and environmentally b...The zero-dimensional(0D)ordered lead-free double perovskites(DPs)Cs_(2)B^((IV))X_(6)have recently been recognized as promising candidates in the optoelectronics domain.Their exceptional stability and environmentally benign nature position them as ideal alternatives to their toxic and unstable lead-based halide perovskite counterparts.Recent years have witnessed notable progress in the optical properties of Cs_(2)B^((IV))X_(6),propelled by techniques such as ion doping,surface coating and ligand modification,which has been instrumental in broadening their applications in various optoelectronic domains.Herein,a comprehensive overview is provided on the recent progress regarding synthesis methods,optimization strategies,bandgap engineering,photoluminescence(PL)optimization,and device applications related to Cs_(2)B^((IV))X_(6)materials.It also explores critical aspects including structural diversity,tunable emission,photophysical mechanisms,and material stability.Moreover,the review addresses the prevailing challenges in this field and outlines future research directions aimed at enhancing the photoluminescence quantum yield and stability of Cs_(2)B^((IV))X_(6).展开更多
All-inorganic perovskite CsPbX_(3)(X=Cl,Br,I)nanocrystals(NCs)have emerged as promising candidates for light-emitting diode(LED)displays due to their outstanding photophysical properties.However,their practical applic...All-inorganic perovskite CsPbX_(3)(X=Cl,Br,I)nanocrystals(NCs)have emerged as promising candidates for light-emitting diode(LED)displays due to their outstanding photophysical properties.However,their practical application remains hindered by poor stability and the inherent toxicity of Pb2+.In this study,we present a two-step heating method to synthesize CsPb_(1-x)Zn_(x)Br_(3)NCs with enhanced optoelectronic performance and uniform dispersion.The optimized Zn^(2+)-doped NCs achieve a photoluminescence quantum yield(PLQY)of 86%,with a reduction in lattice spacing from 0.384 to 0.365 nm,attributed to increased perovskite lattice formation energy and effective surface passivation.To further improve stability,a silica(SiO_(2))shell is introduced via surface modification with(3-aminopropyl)triethoxysilane(APTES),forming CsPb_(0.7)Zn_(0.3)Br_(3)@SiO_(2)core–shell NCs.At an optimal APTES/B-site metal ion molar ratio of 1.8,the PLQY increases to 96%.The SiO2encapsulation significantly enhances environmental stability,with coated NCs retaining 43%of their initial photoluminescence(PL)intensity after immersion in water for 36 h,compared to only 5%for uncoated NCs.Furthermore,after ethanol treatment for 210 min,the coated NCs retain 39%of their initial PL intensity,while the uncoated counterparts retain merely7%.The enhanced stability and luminescence performance of CsPb_(0.7)Zn_(0.3)Br_(3)@SiO_(2)NCs make them highly promising for LED applications.White light-emitting diodes(WLEDs)fabricated using these NCs exhibit a color rendering index(CRI)of 78.2,a correlated color temperature(CCT)of 5470 K,and a luminous efficiency(LE)of 54.2 lm/W,demonstrating significant potential for next-generation display and lighting technologies.展开更多
The development of bifunctional electrocatalysts for hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)at high current density under industrial temperatures is crucial for large-scale industrial hydrog...The development of bifunctional electrocatalysts for hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)at high current density under industrial temperatures is crucial for large-scale industrial hydrogen production from water splitting.In this work,M-MnO_(2)@TNTA composite electrodes were prepared by depositing various metal ion-doped manganese oxide nanoparticles on the titania nanotube array(TNTA)by successive ionic layer adsorption reaction(SILAR)method,and their HER and OER electrocatalytic performances were investigated in 1 M KOH.Results show that the CoFe-MnO_(2)@TNTA composite electrode prepared by simultaneous doping of Co^(3+)and Fe^(3+)in MnO_(2) exhibits optimal catalytic performance.Compared with MnO_(2)@TNTA without ion doping,the overpotentials of CoFe-MnO_(2)@TNTA at 10 mA cm^(-2)(η_(10))for HER and OER are reduced by 571 and 665 mV.In addition,the electrode perfor-mance can be significantly enhanced by increasing the test temperature,and the porous array structure enables CoFe-MnO_(2)@TNTA to exhibit better performance at high current densities.At 50℃,which is the common industrial electrolytic water temperature,the η_(10) of CoFe-MnO_(2)@TNTA for HER is almost equal to that of the Pt/C electrode.The η_(100) of CoFe-MnO_(2)@TNTA for HER is reduced by 35 mV compared with the Pt/C electrode.Moreover,η_(200) of CoFe-MnO_(2)@TNTA for OER is significantly lowered by 111 and 184 mV compared with IrO_(2) and RuO_(2) electrodes.Utilizing CoFe-MnO_(2)@TNTA as both the cathode and anode for overall water splitting,the electrolysis voltage is merely 2.33 V under the current density of 200 mA cm^(-2),much lower than that of IrO_(2)(+)||Pt/C(-)(2.68 V).The present work may provide a valuable reference for the development of self-supporting bifunctional electrodes suitable for high-current-density water splitting at industrial temperatures.展开更多
Rare-earth ion-doped garnets with excellent luminescent properties show great potential for temperature sensing,displays,and nondestructive detection.However,their limited luminescent modes and low photoluminescence q...Rare-earth ion-doped garnets with excellent luminescent properties show great potential for temperature sensing,displays,and nondestructive detection.However,their limited luminescent modes and low photoluminescence quantum yields(PLQY)restrict further applications.In this study,we synthesized Al^(3+),Er^(3+)-co-doped Gd_(3)Ga_(5)O_(12) garnets with multimode luminescence via a high-temperature solid-state method.Notably,the preferential substitution of Al^(3+)ion at octahedral-coordinated GaI sites significantly enhanced the charge density and electron transition probability,achieving a PLQY enhancement of the downshifting luminescence from 35.1%to 68.5%.Al^(3+)ion also influences electron relaxation during up-conversion luminescence,resulting in a color shift from red to yellow to green.Additionally,Al^(3+)incorporation increased the photoelectric conversion efficiency of light-emitting diodes from 2.9%to 6.3%and improved temperature sensing sensitivity from 2.7%to 5.1%K⁻1.This work provides new insights into the photophysical mechanisms and underscores the key role of Al^(3+)ion in optimizing the optical properties of garnet-based materials.展开更多
A series of new oxyapatite red phosphors Ca_(3) Y_(7)(BO_(4)) (SiO_(4))_(5) O doped with different concentrations of Eu^(3+)were successfully synthesized by high temperature solid state method.The X-ray diffraction(XR...A series of new oxyapatite red phosphors Ca_(3) Y_(7)(BO_(4)) (SiO_(4))_(5) O doped with different concentrations of Eu^(3+)were successfully synthesized by high temperature solid state method.The X-ray diffraction(XRD)Rietveld refinement results show that the structure of the phosphor belongs to space group P6_(3)/m and Eu^(3+)ion replaces Y^(3+)ion.The emission spectrum consists of the characteristic emission peaks corresponding to Eu^(3+)under the excitation of 274 nm and the dominant emission peak is at 614 nm(^(5)D_(0)→^(7)F_(2) of Eu^(3+)).The concentration quenching effect occurs and the optimized Eu^(3+)concentration is 4.0 mol%.The energy level diagram for luminous mechanism is also given and the non-radiative energy transfer mechanism between Eu^(3+)is mainly exchange interaction.The CIE coordinate is close to the ideal red light and the color purity is higher than 99.79%.Moreover,the phosphor exhibits moderate thermal stability because the photoluminescence intensity at 423 K is still maintained at higher than 78.97%of that at room temperature.The internal quantum efficiency of Ca_(3) Y_(7)(BO_(4)) (SiO_(4))_(5) O:4.0 mol%Eu^(3+)phosphor is 58.2%.A red light emitting diode(LED)device based on it can emit bright red light.The CCT values of the device are basically unchanged when driven by various bias current.The results show that Ca_(3) Y_(7)(BO_(4)) (SiO_(4))_(5) O:Eu^(3+)is a new type of oxyapatite red fluorescent material with good comprehensive performances.展开更多
With the rapid development of white LEDs,the research of new and efficient white light emitting materials has attracted increasing attention.Zero dimensional(0D)organic–inorganic hybrid metal halide perovskites with ...With the rapid development of white LEDs,the research of new and efficient white light emitting materials has attracted increasing attention.Zero dimensional(0D)organic–inorganic hybrid metal halide perovskites with superior luminescent property are promising candidates for LED application,due to their abundant and tailorable structure.Herein,[(CH_(3))_(3)S]_(2)SnCl_(6)・H_(2)O is synthesized as a host for dopant ions Bi^(3+)and Sb^(3+).The Sb^(3+)doped,or Bi^(3+)/Sb^(3+)co-doped,[(CH_(3))3S]_(2)SnCl_(6)・H_(2)O has a tunable optical emission spectrum by means of varying dopant ratio and excitation wavelength.As a result,we can achieve single-phase materials suitable for emission ranging from cold white light to warm white light.The intrinsic mechanism is examined in this work,to clarify the dopant effect on the optical properties.The high stability of title crystalline material,against water,oxygen and heat,makes it promising for further application.展开更多
基金Technology Innovation Foundation Project for Outstanding Youth of Hebei Uninversity of Technology for financial support
文摘LiFe0.99RE0.01PO4/C cathode material was synthesized by solid-state reaction method using FeC2O4-2H2O, Li2CO3, NH4H2PO4, RE（NO3）3·nH2O as raw materials and glucose as a carbon source. The doping effects of rare earth ions, such as La3＋, Ce3＋, Nd3＋, on the structure and electrochemical properties of LiFePO4/C cathode material were systematically investigated. The as-prepared samples were characterized by means of X-ray diffraction （XRD）, scanning electron microscopy （SEM） and particle size analysis. The electrochemical properties were investigated in terms of constant-current charge/discharge cycling tests. The XRD results showed that the rare earth ions doping did not change the olivine structure of LiFePO4, and all the doped samples were of single-phase with high crystallinity. SEM and particle size analysis results showed that the doping of La3＋, Ce3＋ and Nds＋ led to the decrease of particle size. The electrochemical results exhibited that the doping of La3＋ and Ce3＋ could improve the high-rate capability of LiFePO4/C cathode material, among which, the material doped with 1% Ce3＋ exhibited the optimal electrochemical properties, whose specific discharge capacities could reach 128.9, 119.5 and 104.4 mAh/g at 1C, 2C and 5C rates, respectively.
文摘Polyanion-based materials are considered one of the most attractive and promising cathode materials for lithiumion batteries(LIBs)due to their good stability,safety,cost-effectiveness,suitable voltages,and minimal environmental impact.However,these materials suffer from poor rate capability and low-temperature performance owing to limited electronic and ionic conductivity,which restricts their practical applicability.Recent developments,such as coating material particles with carbon or a conductive polymer,crystal deformation through the doping of foreign metal ions,and the production of nanostructured materials,have significantly enhanced the electrochemical performances of these materials.The successful applications of polyanion-based materials,especially in lithium-ion batteries,have been extensively reported.This comprehensive review discusses the current progress in crystal deformation in polyanion-based cathode materials,including phosphates,fluorophosphates,pyrophosphates,borates,silicates,sulfates,fluorosilicates,and oxalates.Therefore,this review provides detailed discussions on their synthesis strategies,electrochemical performance,and the doping of various ions.
文摘Ultrathin TiO_(2)nanosheets with coexposed{001}/{101}facets have attracted considerable attention because of their high photocatalytic activity.However,the charge-separated states in the TiO_(2)nanosheets must be extended to further enhance their photocatalytic activity for H_(2)evolution.Herein,we present a successful attempt to selectively dope lanthanide ions into the{101}facets of ultrathin TiO_(2)nanosheets with coexposed{001}/{101}facets through a facile one-step solvothermal method.The lanthanide doping slightly extended the light-harvesting region and markedly improved the charge-separated states of the TiO_(2)nanosheets as evidenced by UV-vis absorption and steady-state/transient photoluminescence spectra.Upon simulated sunlight irradiation,we observed a 4.2-fold enhancement in the photocatalytic H_(2)evolution activity of optimal Yb^(3+)-doped TiO_(2)nanosheets compared to that of their undoped counterparts.Furthermore,when Pt nanoparticles were used as cocatalysts to reduce the H_(2)overpotential in this system,the photocatalytic activity enhancement factor increased to 8.5.By combining these results with those of control experiments,we confirmed that the extended charge-separated states play the main role in the enhancement of the photocatalytic H_(2)evolution activity of lanthanide-doped TiO_(2)nanosheets with coexposed{001}/{101}facets.
基金Project supported by Beijing Excellent Talents Training Fund (20061D0502200299)
文摘In this study, nanosized TiO2 co-doped with Fe3+ and Nd3+ ions was synthesized via a sol-gel method. The metallic ion doped TiO2 was thoroughly characterized with XRD and UV-vis, and the photocatalytic activity was evaluated by degrading methylene blue (MB) solution. The results indicated that TiO2 crystalline size was reduced and phase transformation of anatase to rutile was suppressed as the content of doped Nd3+ ion increased in the co-doped TiO2. The UV-vis spectra of co-doped TiO2 seemed to simply overlay two spectra of single metal doped TiO2, and had significantly increased absorbance in the ranges of 400～500 nm, 565～600 nm and 730～765 nm as compared to pure TiO2. The photocatalytic activity of co-doped TiO2 was obviously enhanced, and raised about 30% compared to that of pure TiO2 as doped Nd3+ content was 0.15% and Fe3+ content was 0.05%, respectively. The enhanced catalytic activity was attributed to a synergistic effect of two doped ions, where doped Fe3+ ion inhibited the recombination of photogenerated electron and hole, and Nd3+ ion brought more surface carboxyl to promote the degradation reaction.
基金supported by the National Basic Research Program of China (973) (2007CB31407)Foundation for Innovative Research Groups of the NSFC (60721001)+1 种基金the Young Fund of Sichuan Province (08ZQ026-013)the National Natural Science Foundation of China (50972023, 50872078)
文摘Ca1-xRxCu3Ti4O12(R=La,Y,Gd;x=0,0.1,0.2,0.3) electronic ceramics were fabricated by conventional solid-state reaction method.The microstructure and dielectric properties as well as impedance behavior were carefully investigated.XRD results showed that the secondary phases with the general formula R2Ti2O7 existed at grain boundaries of rare earth doped ceramics,which inhibited abnormal grain growth.The dielectric constant decreased from 4×105 in pure CaCu3Ti4O12(CCTO) ceramics to 2×103 with rare earth doping....
基金Project supported by the National Natural Science Foundation of China (20071031)
文摘The doping effects of La^3＋, Gd^3＋ and Lu^3＋ on the crystal structure and luminescence properties of （Yo96-x LnxCe0.04）3Al5O12（Ln = Gd, La, Lu） phosphors were studied. The X-ray diffraction patterns presented that with the inerease of the doping concentrations of La^3＋ and Gd^3＋ ions, the d-value of （Y0.96-xLnxCe0.04）3Al5O12 （Ln = Gd, La） inereased and the larger the doping ion, the stronger the effect would be. The doping amount causing phase transition in （Y0.96-xLnxCe0.04）3Al5O12 decreased with the inerease of the ionic radii of the doping lanthanide ions （La^3＋： 0.106 nm, Gd^3＋： 0. 094 nm, Lu^3＋ ： 0.083 nm）. The bigger doping ion of Gd^3＋ made the emission of （Y0.96-xGdxCe0.04）3Al5O12 move to red spectral region, but the smaller one of Lu^3＋ made it blue.
基金Project supported by National Natural Science Foundation of China (51462010)Natural Science Foundation of Jiangxi Province(20161BAB206132,20171ACB20022)The Innovation fund of Jingdezhen Ceramic Institute (JYC-201803)。
文摘In this study,K+-doped γ-Ce2 S3 was successfully prepared via a gas-solid reaction method using CeO2,K2 CO3,and CS2 as raw materials.The effects of the suitable sulfide system and different molar ratios of K to Ce(nK/Ce=0-0.30) on the phase composition,crystal structure,chromaticity and thermal stability ofγ-Ce2 S3 were systematically investigated.Pure γ-Ce2 S3 was obtained by calcining the doped samples at840℃ for 150 min.After calcination at the same temperature the undoped K+samples exhibit a pure α-phase.Samples with a K/Ce molar ratio(nK/Ce) of 0.10-0.25 comprise only the γ-phase;and when nK/Ce exceeds 0.25,a new heterogeneous phase,KCeS2,emerges.For values of nK/Ce in the range of0-0.25,the γ-Ce2 S3 lattice parameters gradually increases with increasing K+ content.When nK/Ceexceedes 0.25,the lattice parameters remains unchanged.As nK/Ce increased,the synthesized color gradually changes from red to orange—red and finally,to yellow.The redness value a* reaches the maximum(L*=33.86,a*=36.68,b*=38.15) when nK/Ce=0.10,The nK/Ce=0.10 composition continues to exhibit the y-phase after heat treatment at 420℃ for 10 min in air.The K+doping fills the internal vacancies of γ-Ce2 S3 and formed a solid solution,which is beneficial for the stability of its lattice,thus improving the thermal stability of γ-Ce2 S3(from 350 to 420℃).
基金supported by the National Natural Science Foundation of China (52202001)Open Project of Advanced Laser Technology Laboratory of Anhui Province (AHL2021KF07)+1 种基金Major Science and Technology of Anhui Province(202203a05020002)University Natural Science Research Project of Anhui Province (KJ2021A0388)。
文摘In this work,a series of self-activated KYb(MoO_(4))_(2) phosphors with various x at% Er^(3+) doping concentrations(x=0.5,1,3,5,8,10,15) was synthesized by the solid-state reaction method.The phase structure of the as-prepared samples was analyzed by X-ray diffraction(XRD),XRD Rietveld refinement and Fourier transform infrared(FT-IR) spectroscopy.The as-prepared samples retain the orthorhombic structure with space group of Pbcn even Er^(3+) doping concentration up to 15 at%.High-purity upconversion(UC) green emission with green to red intensity ratio of 55 is observed from the as-prepared samples upon the excitation of 980 nm semiconductor laser and the optimum doping concentration of Er^(3+) ions in the self-activated KYb(MoO_(4))_(2) host is revealed as 3 at%.The strong green UC emission is confirmed as a two-photon process based on the power-dependent UC spectra.In addition,the fluorescence intensity ratios(FIRs) of the two thermally-coupled energy levels,namely ^(2)H_(11/2) and ^(4)S_(3/2).of Er^(3+) ions were investigated in the temperature region 300-570 K to evaluate the optical temperature sensor behavior of the sample.The maximum relative sensitivity(S_(R)) is determined to be 0.0069 K^(-1) at300 K and the absolute sensitivity(S_(A)) is determined to be 0.0126 K^(-1) at 300 K.The S_(A) of self-activated KYb(MoO_(4))2:Er^(3+)is almost twice that of traditional KY(MoO_(4))2:Er^(3+)/Yb^(3+)codoping phosphor.The results demonstrate that Er^(3+) ions doped self-activated KYb(MoO_(4))2 phosphor has promising application in visible display,trademark security and optical temperature sensors.
基金Supported by National Natural Science Foundation of China (No. 10975020)Key Laboratory of Beam Technology and Material Modification of Ministry of Education, Beijing Normal University
文摘The electronic state density and energy bands of Ag-doped anatase TiO2 are studied by WIEN2k software package based on DFT. The calculation results show that the band-gap of anatase titania became bigger after doping with Ag metal ions. The band-gap transfers from 2.04 to 2.5 eV, but a new energy band appears among the forbidden band after the Ag atom substitution. The interband width of Ag-TiO2 is 0.17 eV, which is located at –0.07 eV; more excitation and jump routes are opened for the electrons. The lowest excitation energy can achieve 1.2 eV, which may allow the photons with lower energy （at longer wavelength, such as visible light） to be absorbed. Ag ions are implanted into the titania nanotube sample by MEVVA （Metal Vapor Vacuum Arc） implanter. The photo-electrochemical response and photo-degradation experiment of titania nanotube samples implanted with Ag ions are tested under UV and visible light; the results indicated that the performance of implanted titania naotubes is enhanced both under UV and visible light; it is worth mentioning that the photocurrent density can reach 0.145 mA/cm2 under visible light, which is 181 times higher than those of pure TiNT, and the k value of degradation methyl orange can obtain 0.30 h-1, which is 71 times higher than that of pure TiNT. All the experimental results are consistent well with the theoretic ones.
基金Education Department of Liaoning Province National Science Foundation(2008615)
文摘Microporous titanium dioxide thin films have been fabricated on titanium plates by the micro-plasma oxidation method with the electrolyte of Na3PO4+Na2B4O7.The influence of V5+ions addition in the electrolyte on the photocatalytic activities was investigated.A kind of typical textile industry pollutant(methylene blue)was used to evaluate the photo-catalytic activity of the films.The results showed that this activity of the films had been improved by adding V5+ions into the electrolyte solution.The removal of methylene blue reaches 90%for 60 min when V5+ions addition concentrate is 0.3 g/L.X-ray diffraction,scanning electron microscopy and atomic force microscopy techniques were applied to characterize the modified films.Experimental results show that the improvement in activity was related to the forming of titanium dioxide lattice distortion,which could accept more photoexcitated holes and produce more strong surface free radicals to oxidate adsorptive molecules.
基金financially supported by the Scientific Research Startup Fund for Shenzhen High-Caliber Personnel of SZPT(No.6021310029K)Research Projects of Department of Education of Guangdong Province(No.2023KTSCX319)。
文摘It is a difficult challenge to simultaneously employ the cationic and anionic redox chemistry in cathode materials for sodium-ion batteries with high energy.Even though layered oxides(classified as two-dimensional oxides)demonstrate excellent promise in the high discharge capacity,their poor oxygen transformation via redox reactions is limited by crystal instability.Therefore,a doping strategy was conceived to tackle this issue and increase redox efficiency.K doping was applied to transform the two-dimensional Na_(1.3)Mn_(0.7)O_(2)(NMO)to threedimensional K_(0.2)Na_(1.3)Mn_(0.5)O_(2)(KNMO),preventing the irreversible phase shift and preserving the crystal structure’s stability while cycling.With this modification treatment,KNMO features manganese and oxygen reactive sites,delivering a promising energy density of 190mAh·g^(-1)at 5 mA·g^(-1)in the 2.0–4.5 V voltage range(vs71.4 mAh·g^(-1)for the pristine NMO).Moreover,it displays improved capacity retention of more than 83.5%after 50cycles at 50 mA·g^(-1).The results demonstrated that doped intercalation oxides were promising for redox oxygen transformation in sodium-ion batteries.
基金the National Natural Science Foundation of China(No.51662005)。
文摘The rare earth ion Yb^3+ doped Bi2WO6 photocatalysts were synthesized by hydrothermal method.Moreover,XRD,XPS,FESEM,TEM,Ramam,N2 adsorption-desorption isotherm measurements and UV-vis diffusion reflectance spectra were used to characterize the Yb^3+ doped Bi2WO6 photocatalysts.The morphology,specific surface area,and pore volume distribution were greatly affected after Yb3+ ions doping.Photocatalytic performance of Bi2WO6 was effectively enhanced after Yb3+ ions doping,6% Yb^3+ doped Bi2WO6 had the best photocatalytic performance,and 96.2% Rhodamine B was degradated after irradiated 30 min,which was 1.29 times that of the pristine one.The enhanced photocatalytic performance was due to the increased specific surface area,decreased energy band gap and inhibition of photoelectron-hole recombination after Yb3+ ions doping.
基金This work was financially supported by the Key Program of Frontier Science of Chinese Academy of Sciences(QYZDY-SSW-JSC038)the Natural Science Foundation of Guangdong Province(2017A030310185)the Science and Technology Planning Project of Guangzhou,China(201704030040).
文摘Sulfur dioxide(SO_(2))emissions from diesel exhaust pose a serious threat to the environment and human health.Thus,desulfurization technology and the performance of desulfurization materials must be improved.In this study,MnO_(2) was modified with various alkali metal ions using the impregnation method to enhance its SO_(2) capture performance.The composites were characterized intensively by scanning electron microscopy,energydispersive X-ray spectroscopy,X-ray diffraction spectroscopy,and Brunauer-Emmett-Teller theory.The SO_(2) capture performance of these composites were measured via thermogravimetry,and the effect of doping with alkali metal ions on the SO_(2) capture performance of MnO_(2) was investigated.Results showed that the SO_(2) capture performance of MnO_(2) could be enhanced by doping with alkali metal ions,and the MnO_(2) composite doped with LiOH(2.0 mol/L)had the best SO_(2) capture capacity(124 mgSO_(2)/gMaterial),which was 18%higher than that of pure MnO_(2).Moreover,the type and concentration of alkali metal ions had varying effects on the SO_(2) capture performance of MnO_(2).In our experiment,the SO_(2) capture performance of the MnO_(2) doped with NaOH,LiCl,Na2CO3,K2CO3,and Li2CO3 composites were worse than that of pure MnO_(2).Therefore,the influences of the type and concentration of alkali metal ions to be doped into desulfurization materials must be considered comprehensively.
基金Project(2024YFD2101000)supported by the National Key R&D Program of ChinaProject(62004143)supported by the National Natural Science Foundation of China+5 种基金Project(2022BAA084)supported by the Key R&D Program of Hubei Province,ChinaProject(2024JJ7231)supported by the Hunan Provincial Natural Science Foundation of ChinaProject(2023GK2040)supported by the Key R&D Program Projects in Hunan Province,ChinaProject(22C0306)supported by the Scientific Research Fund of Hunan Provincial Education Department,ChinaProject(2023KFKT06)supported by the“Research and Development of Degradable Materials and Forming Technology”Open Project of Hunan Engineering Research Center,ChinaProject(LCX202404)supported by the Innovation Project of Engineering Research Center of Phosphorus Resources Development and Utilization of Ministry of Education,China。
文摘The zero-dimensional(0D)ordered lead-free double perovskites(DPs)Cs_(2)B^((IV))X_(6)have recently been recognized as promising candidates in the optoelectronics domain.Their exceptional stability and environmentally benign nature position them as ideal alternatives to their toxic and unstable lead-based halide perovskite counterparts.Recent years have witnessed notable progress in the optical properties of Cs_(2)B^((IV))X_(6),propelled by techniques such as ion doping,surface coating and ligand modification,which has been instrumental in broadening their applications in various optoelectronic domains.Herein,a comprehensive overview is provided on the recent progress regarding synthesis methods,optimization strategies,bandgap engineering,photoluminescence(PL)optimization,and device applications related to Cs_(2)B^((IV))X_(6)materials.It also explores critical aspects including structural diversity,tunable emission,photophysical mechanisms,and material stability.Moreover,the review addresses the prevailing challenges in this field and outlines future research directions aimed at enhancing the photoluminescence quantum yield and stability of Cs_(2)B^((IV))X_(6).
基金supported by the National Natural Science Foundation of China(No.52062019)the Natural Science Research Project of Higher Education Institutions in Jiangsu Province,China(No.24KJA430013)the Natural Science Foundation of Jiangsu Province for Youths,China(No.BK20230662)。
文摘All-inorganic perovskite CsPbX_(3)(X=Cl,Br,I)nanocrystals(NCs)have emerged as promising candidates for light-emitting diode(LED)displays due to their outstanding photophysical properties.However,their practical application remains hindered by poor stability and the inherent toxicity of Pb2+.In this study,we present a two-step heating method to synthesize CsPb_(1-x)Zn_(x)Br_(3)NCs with enhanced optoelectronic performance and uniform dispersion.The optimized Zn^(2+)-doped NCs achieve a photoluminescence quantum yield(PLQY)of 86%,with a reduction in lattice spacing from 0.384 to 0.365 nm,attributed to increased perovskite lattice formation energy and effective surface passivation.To further improve stability,a silica(SiO_(2))shell is introduced via surface modification with(3-aminopropyl)triethoxysilane(APTES),forming CsPb_(0.7)Zn_(0.3)Br_(3)@SiO_(2)core–shell NCs.At an optimal APTES/B-site metal ion molar ratio of 1.8,the PLQY increases to 96%.The SiO2encapsulation significantly enhances environmental stability,with coated NCs retaining 43%of their initial photoluminescence(PL)intensity after immersion in water for 36 h,compared to only 5%for uncoated NCs.Furthermore,after ethanol treatment for 210 min,the coated NCs retain 39%of their initial PL intensity,while the uncoated counterparts retain merely7%.The enhanced stability and luminescence performance of CsPb_(0.7)Zn_(0.3)Br_(3)@SiO_(2)NCs make them highly promising for LED applications.White light-emitting diodes(WLEDs)fabricated using these NCs exhibit a color rendering index(CRI)of 78.2,a correlated color temperature(CCT)of 5470 K,and a luminous efficiency(LE)of 54.2 lm/W,demonstrating significant potential for next-generation display and lighting technologies.
基金financially supported by the National Natural Science Foundation of China(No.51972095).
文摘The development of bifunctional electrocatalysts for hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)at high current density under industrial temperatures is crucial for large-scale industrial hydrogen production from water splitting.In this work,M-MnO_(2)@TNTA composite electrodes were prepared by depositing various metal ion-doped manganese oxide nanoparticles on the titania nanotube array(TNTA)by successive ionic layer adsorption reaction(SILAR)method,and their HER and OER electrocatalytic performances were investigated in 1 M KOH.Results show that the CoFe-MnO_(2)@TNTA composite electrode prepared by simultaneous doping of Co^(3+)and Fe^(3+)in MnO_(2) exhibits optimal catalytic performance.Compared with MnO_(2)@TNTA without ion doping,the overpotentials of CoFe-MnO_(2)@TNTA at 10 mA cm^(-2)(η_(10))for HER and OER are reduced by 571 and 665 mV.In addition,the electrode perfor-mance can be significantly enhanced by increasing the test temperature,and the porous array structure enables CoFe-MnO_(2)@TNTA to exhibit better performance at high current densities.At 50℃,which is the common industrial electrolytic water temperature,the η_(10) of CoFe-MnO_(2)@TNTA for HER is almost equal to that of the Pt/C electrode.The η_(100) of CoFe-MnO_(2)@TNTA for HER is reduced by 35 mV compared with the Pt/C electrode.Moreover,η_(200) of CoFe-MnO_(2)@TNTA for OER is significantly lowered by 111 and 184 mV compared with IrO_(2) and RuO_(2) electrodes.Utilizing CoFe-MnO_(2)@TNTA as both the cathode and anode for overall water splitting,the electrolysis voltage is merely 2.33 V under the current density of 200 mA cm^(-2),much lower than that of IrO_(2)(+)||Pt/C(-)(2.68 V).The present work may provide a valuable reference for the development of self-supporting bifunctional electrodes suitable for high-current-density water splitting at industrial temperatures.
基金supported by the Guangxi Natural Science Foundation(Grant No.2025GXNSFDA069038)The Guangxi Science and Technology Plan Project(Grant No.AA23073018)+1 种基金the National Natural Science Foundation of China(Grant Nos.22175043 and 52162021)the Open Foundation of State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures(Grant No.MMCS2023OF05).
文摘Rare-earth ion-doped garnets with excellent luminescent properties show great potential for temperature sensing,displays,and nondestructive detection.However,their limited luminescent modes and low photoluminescence quantum yields(PLQY)restrict further applications.In this study,we synthesized Al^(3+),Er^(3+)-co-doped Gd_(3)Ga_(5)O_(12) garnets with multimode luminescence via a high-temperature solid-state method.Notably,the preferential substitution of Al^(3+)ion at octahedral-coordinated GaI sites significantly enhanced the charge density and electron transition probability,achieving a PLQY enhancement of the downshifting luminescence from 35.1%to 68.5%.Al^(3+)ion also influences electron relaxation during up-conversion luminescence,resulting in a color shift from red to yellow to green.Additionally,Al^(3+)incorporation increased the photoelectric conversion efficiency of light-emitting diodes from 2.9%to 6.3%and improved temperature sensing sensitivity from 2.7%to 5.1%K⁻1.This work provides new insights into the photophysical mechanisms and underscores the key role of Al^(3+)ion in optimizing the optical properties of garnet-based materials.
基金Project supported by the National Natural Science Foundation of China(51972213,61605116,51972208,51802196).
文摘A series of new oxyapatite red phosphors Ca_(3) Y_(7)(BO_(4)) (SiO_(4))_(5) O doped with different concentrations of Eu^(3+)were successfully synthesized by high temperature solid state method.The X-ray diffraction(XRD)Rietveld refinement results show that the structure of the phosphor belongs to space group P6_(3)/m and Eu^(3+)ion replaces Y^(3+)ion.The emission spectrum consists of the characteristic emission peaks corresponding to Eu^(3+)under the excitation of 274 nm and the dominant emission peak is at 614 nm(^(5)D_(0)→^(7)F_(2) of Eu^(3+)).The concentration quenching effect occurs and the optimized Eu^(3+)concentration is 4.0 mol%.The energy level diagram for luminous mechanism is also given and the non-radiative energy transfer mechanism between Eu^(3+)is mainly exchange interaction.The CIE coordinate is close to the ideal red light and the color purity is higher than 99.79%.Moreover,the phosphor exhibits moderate thermal stability because the photoluminescence intensity at 423 K is still maintained at higher than 78.97%of that at room temperature.The internal quantum efficiency of Ca_(3) Y_(7)(BO_(4)) (SiO_(4))_(5) O:4.0 mol%Eu^(3+)phosphor is 58.2%.A red light emitting diode(LED)device based on it can emit bright red light.The CCT values of the device are basically unchanged when driven by various bias current.The results show that Ca_(3) Y_(7)(BO_(4)) (SiO_(4))_(5) O:Eu^(3+)is a new type of oxyapatite red fluorescent material with good comprehensive performances.
基金supported by the National Natural Science Foundation of China(NSFC)(Grant Nos.22373014 and 22371043)the Natural Science Foundation of Fujian Province(No.2022J06019)the Open Project Program of Wuhan National Laboratory for Optoelectronics(No.2020WNLOKF009).
文摘With the rapid development of white LEDs,the research of new and efficient white light emitting materials has attracted increasing attention.Zero dimensional(0D)organic–inorganic hybrid metal halide perovskites with superior luminescent property are promising candidates for LED application,due to their abundant and tailorable structure.Herein,[(CH_(3))_(3)S]_(2)SnCl_(6)・H_(2)O is synthesized as a host for dopant ions Bi^(3+)and Sb^(3+).The Sb^(3+)doped,or Bi^(3+)/Sb^(3+)co-doped,[(CH_(3))3S]_(2)SnCl_(6)・H_(2)O has a tunable optical emission spectrum by means of varying dopant ratio and excitation wavelength.As a result,we can achieve single-phase materials suitable for emission ranging from cold white light to warm white light.The intrinsic mechanism is examined in this work,to clarify the dopant effect on the optical properties.The high stability of title crystalline material,against water,oxygen and heat,makes it promising for further application.
