A novel up-converting phosphor,Na_xAl_yF_（x＋3y）/CaF2（0.3 〈 x 〈 0.5,0 〈 y 〈 0.1） composite,is prepared by a hydrothermal process at 180°C and an annealing treatment at 500℃.X-ray diffraction（XRD） patte...A novel up-converting phosphor,Na_xAl_yF_（x＋3y）/CaF2（0.3 〈 x 〈 0.5,0 〈 y 〈 0.1） composite,is prepared by a hydrothermal process at 180°C and an annealing treatment at 500℃.X-ray diffraction（XRD） pattern indicates that Na_xAl_yF_（x＋3y）/CaF_2 is a composite consisting of NaF,Na_3 AlF_6,and CaF_2.The up-conversion luminescence properties of this phosphor are investigated by fluorescence spectrometer.Results show that Na_xAl_yF_（x＋3y）/CaF_2 exhibits visible-to-ultraviolet up-conversion luminescence properties.The emission peaks at 316 and 336 nm are observed when excited by 610 nm,the luminescence lifetime of the emissions is great than 18 ms,and the internal fluorescence quantum yield is 4.2%.Additionally,the luminescent mechanism of this phosphor is also mentioned.展开更多
Background:Methodological applications of the high sensitivity genus-specific Schistosoma CAA strip test,allowing detection of single worm active infections(ultimate sensitivity),are discussed for efficient utilizatio...Background:Methodological applications of the high sensitivity genus-specific Schistosoma CAA strip test,allowing detection of single worm active infections(ultimate sensitivity),are discussed for efficient utilization in sample pooling strategies.Besides relevant cost reduction,pooling of samples rather than individual testing can provide valuable data for large scale mapping,surveillance,and monitoring.Method:The laboratory-based CAA strip test utilizes luminescent quantitative up-converting phosphor(UCP)reporter particles and a rapid user-friendly lateral flow(LF)assay format.The test includes a sample preparation step that permits virtually unlimited sample concentration with urine,reaching ultimate sensitivity(single worm detection)at 100%specificity.This facilitates testing large urine pools from many individuals with minimal loss of sensitivity and specificity.The test determines the average CAA level of the individuals in the pool thus indicating overall worm burden and prevalence.When requiring test results at the individual level,smaller pools need to be analysed with the pool-size based on expected prevalence or when unknown,on the average CAA level of a larger group;CAA negative pools do not require individual test results and thus reduce the number of tests.Results:Straightforward pooling strategies indicate that at sub-population level the CAA strip test is an efficient assay for general mapping,identification of hotspots,determination of stratified infection levels,and accurate monitoring of mass drug administrations(MDA).At the individual level,the number of tests can be reduced i.e.in low endemic settings as the pool size can be increased as opposed to prevalence decrease.Conclusions:At the sub-population level,average CAA concentrations determined in urine pools can be an appropriate measure indicating worm burden.Pooling strategies allowing this type of large scale testing are feasible with the various CAA strip test formats and do not affect sensitivity and specificity.It allows cost efficient stratified testing and monitoring of worm burden at the sub-population level,ideally for large-scale surveillance generating hard data for performance of MDA programs and strategic planning when moving towards transmission-stop and elimination.展开更多
An optical biosensor with up-converting phosphor （UCP） marker is developed for the sensitive rapid immunoassay to the specific biomolecule. UCP can emit visible light when excited by infrared light. Through detectin...An optical biosensor with up-converting phosphor （UCP） marker is developed for the sensitive rapid immunoassay to the specific biomolecule. UCP can emit visible light when excited by infrared light. Through detecting and analyzing the content of UCP particles on the test strip after immunoreaction, the concentration of target analyte in the sample can be obtained. The detection sensitivity to plague IgG is better than 5 ng/ml; to plague FI-Ab is better than 100 pg/ml; to plague Yersinia pestis cell is better than 3 ×10^4 CFU/ml. Good linear response characteristics and an excellent correlation （R^2 ≥ 0.95） have been verified by quantitative detection results. In the practical application, detection results to 167 analytic samples have an excellent consistency with those obtained by reverse hemagglutination test. The up-converting phosphor technology （UPT） based biosensor has stable, reliable, and sensitive performances. It can meet the need of various bioassay applications.展开更多
To completely recover valuable elements and reduce the amount of waste,the impact of phosphoric acid on the decomposition of rare earth,fluorine and phosphorus during cyclic leaching was studied based on the character...To completely recover valuable elements and reduce the amount of waste,the impact of phosphoric acid on the decomposition of rare earth,fluorine and phosphorus during cyclic leaching was studied based on the characteristics of low-tempe rature sulfuric acid deco mposition.When a single monazite was leached using 75 wt% H_(2)SO_(4) solution with phosphoric acid,the size and number of monazite particles in the washing slag gradually decrease with the increase in phosphoric acid content in the leaching solution.The monazite phase can hardly be found in the slag when the phosphoric acid content reaches 70 g/L,which indicates that phosphoric acid is favorable for monazite decomposition.The mixed rare earth concentrate was leached by 75 wt% H_(2)SO_(4) containing 70 g/L phosphoric acid,the mineral compositions of the washing slag are only gypsum and unwashed rare earth sulfuric acid.After cyclic leaching of75 wt% H_(2)SO_(4),the mineral compositions of the primary leaching washing slag are mainly undecomposed monazite,rare earth sulfate and calcium sulfate.However,monazite is not found in the mineral phase of the second and third leaching washing slag.The leaching rates of rare earth and phosphorus gradually increase with the increase in cyclic leaching times.In addition,the phosphoric acid content in the leaching solution increases with the increase in the number of cyclic leaching time.However,the rising trend decreases when the phosphoric acid content reaches 50 g/L by adsorption and crystallization of phosphoric acid.A small amount of water can be used to clean the leaching residue before washing to recover the more soluble phosphorus acid according to the difference of dissolution between phosphoric acid and rare earth sulfuric acid.展开更多
The catalytic enantioselective electrophilic amination reaction has emerged as a highly efficient method for synthesizing diverse nitrogen-containing chiral molecules,with the development of various asymmetric catalys...The catalytic enantioselective electrophilic amination reaction has emerged as a highly efficient method for synthesizing diverse nitrogen-containing chiral molecules,with the development of various asymmetric catalysis systems.Chiral phosphoric acids(CPA)have been widely acknowledged as versatile chiral organocatalysts since it was first discovered in 2004,finding application in catalyzing diverse asymmetric reactions.A comprehensive overview of recent advances in CPA-catalyzed asymmetric electrophilic amination reactions using different N-electrophilic reagents,including azo reagents,aryldiazonium salts,and imine derivatives,is presented.Furthermore,insights into future developments in this field are offered.展开更多
Bifunctional applications in solid state lighting and optical thermometry are attractive in the optical field.Despite Eu^(3+)doped phosphors are widely used in white-LEDs,phosphors with high temperature sensitivity re...Bifunctional applications in solid state lighting and optical thermometry are attractive in the optical field.Despite Eu^(3+)doped phosphors are widely used in white-LEDs,phosphors with high temperature sensitivity remain rare.Herein,NaLnTe_(2)O_(7):Eu^(3+)(Ln=Y and Gd)phosphors were synthesized using a rapid microwave-assisted solidstate(MASS)method to fulfill these applications.Under 395 nm excitation,NaLnTe_(2)O_(7):Eu^(3+)exhibit the characteristic ^(5)D_(0)→^(7)F_(J)(J=1–4)transitions of Eu^(3+).Substituting Gd^(3+) for Y^(3+) enhances the luminescence by approximately 2.42 times.Structural analyses reveal that the improved luminescent properties are attributed to the more distorted and appropriate coordination environment in NaGdTe_(2)O_(7):Eu^(3+).Finally,white-LEDs using NaGdTe_(2)O_(7):Eu^(3+)as the red-component produce white light with high Ra of 89.Furthermore,the distinct thermal responses of the ^(5)D_(0)→^(7)F_(J) transitions enable NaLnTe_(2)O_(7):Eu^(3+)to function as temperature sensors via fluorescence intensity ratio(FIR)strategy.NaYTe_(2)O_(7):Eu^(3+)possesses the maximum relative/absolute sensitivity of 1.45%/15.93%K^(-1),whereas NaGdTe_(2)O_(7):Eu^(3+)achieves the maximum relative/absolute sensitivity of 1.53%/30.24% K^(-1).This work highlights the significance of cationic substitution in enhancing luminescent properties for multifunctional applications.展开更多
The work deals with cellulose paper filled with nanocellulose and SrAl_(2)O_(4):Eu,Dy oxide phosphor.It was found that both nanocellulose and oxide improve the tensile strength of the composites obtained.The samples w...The work deals with cellulose paper filled with nanocellulose and SrAl_(2)O_(4):Eu,Dy oxide phosphor.It was found that both nanocellulose and oxide improve the tensile strength of the composites obtained.The samples with the oxide demonstrate a long-lasting photoluminescence(PL)under sunlight and ultra-violet(UV)illumination.Room-temperature the PL spectra reveal a wide multicomponent band spreading over all the visible spectral regions.The short-wavelength part of the band is ascribed to the cellulose-related luminescence,while the long-wavelength PL component with maxima near 540 nm corresponds to the luminescence of the SrAl_(2)O_(4):Eu,Dy phosphor.The dependency of the PL intensity on oxide concentration suggests the reabsorption of cellulose emission by the oxide and vice versa.The study of the dielectric properties of composite papers shows the presence of dielectric relaxations at low temperatures(T~−50℃).Similar cellulose materials to those studied can be considered as alternatives for artificial petroleum-based polymers.Low cost,eco-friendliness,biocompatibility,and the simplicity of recycling are among the main advantages of these materials.They are produced from the cellulose which is one of the most abundant renewable materials in nature.The data on the mechanical,dielectric,and optical properties indicate that the papers studied can be used in flexible lighting devices,WLEDs,coating,markers,labels,etc.展开更多
Broadband near-infrared(NIR)phosphor-conve rted light-emitting diode(pc-LED)is a new generation of light source for spectroscopy applications.Current studies generate a broad continuous NIR spectrum to promise the det...Broadband near-infrared(NIR)phosphor-conve rted light-emitting diode(pc-LED)is a new generation of light source for spectroscopy applications.Current studies generate a broad continuous NIR spectrum to promise the detection of a wide range of substances.This paper reports a discontinuous NIR spectral distribution peaking at 760 and 1400 nm,respectively,by co-doping Cr^(3+)and Ni^(2+)ions into CaLu_(2)Mg_(2)Si_(3)O_(12)garnet.The benefit of such a discontinuous spectrum is its ability to prevent energy waste in specific applications,such as moisture(freshness)and hemoglobin detection,where only spectral bands near 750 and 1500 nm are required.The discontinuous spectrum is attributed to the ene rgy transfer from Cr^(3+)to Ni^(2+)ions.The NIR pc-LED fabricated by the new phosphor shows photoelectric efficiency of 9.12%@10 mA and NIR output power of 11.44 mW@100 mA.The NIR pc-LED also performs well when measuring alcohol solution where only a discontinuous spectrum is needed.These results highlight the potential of NIR phosphors with a discontinuous spectrum across a broad 700-1600 nm range.展开更多
Sodium-ion batteries(SIBs) are promising electrochemical energy storage systems as lithium-ion batteries by virtue of their similar chemical properties and natural abundance and availability.However,the ionic radius o...Sodium-ion batteries(SIBs) are promising electrochemical energy storage systems as lithium-ion batteries by virtue of their similar chemical properties and natural abundance and availability.However,the ionic radius of Na^(+)is larger than that of Li^(+),leading to challenges in its insertion/extraction at anode side.As a class of anode materials,phosphorus allotropes(PAs,red,and black) and metal phosphides(MPs) have shown great prospects because of high theoretical gravimetric/volumetric capacity,high carrier mobility,and suitable redox potential.In this review,recent developments in the studies of PAs and MPs with particular emphasis on understanding sodium storage mechanisms,developing novel synthesis strategies,and performance validations have been manifested valuable solutions to address these challenges.We begin with the introduction and classification of the macroscopic sodiation mechanisms of PAs and MPs,and the various fabrication strategies of PAs and MPs are comprehensively summarized in second section.The third section thoroughly reviews the progresses on PAs and MPs-based advanced materials for their application in SIBs.Finally,we also discuss the significant challenges and outline a roadmap for future research directions.展开更多
This investigation evaluated the impact of as-is biochar(BC)and phosphorous(P)-loaded biochar(PBC)(3%)on the growth and biochemical characteristics of rice under exposure to vanadium(V)(60 mg L^(-1)).The results indic...This investigation evaluated the impact of as-is biochar(BC)and phosphorous(P)-loaded biochar(PBC)(3%)on the growth and biochemical characteristics of rice under exposure to vanadium(V)(60 mg L^(-1)).The results indicate that rice plants exposed to a V-only treatment experienced declines in several growth parameters.Conversely,the inclusion of BC and PBC caused noteworthy increases in physiological traits.PBC performed well in stress environments.Specifically,the shoot and root fresh weights increased by 82.86 and 53.33%,respectively,when compared to the V-only treatment.In addition,the SPAD chlorophyll of the shoot increased by 13.05%relative to the V-amended plants.Moreover,including BC and PBC improved the antioxidant enzyme traits of plant shoot and root,such as significant increases in superoxide dismutase(SOD by 56.11 and 117.35%),catalase(CAT by 34.19 and 35.77%),and peroxidase(POD by 25.90 and 18.74%)when compared to V-only amended plants,respectively.These findings strongly suggest that the application of BC and PBC can trigger biochemical pathways that facilitate biomass accumulation in meristematic cells.However,further investigations are required to elucidate the underlying mechanisms responsible for this growth promotion.展开更多
Er^(3+)-doped BaLaGaO_(4)green phosphors was synthesized through a high-temperature solid-state reaction technique.The phase structure and morphology test results of the phosphor indicate that the BaLaGaO_(4)material ...Er^(3+)-doped BaLaGaO_(4)green phosphors was synthesized through a high-temperature solid-state reaction technique.The phase structure and morphology test results of the phosphor indicate that the BaLaGaO_(4)material was successfully synthesized and Er^(3+)ions were successfully doped into the main lattice.This doping does change the basic structure of the crystal.BaLaGaO_(4):Er^(3+)phosphor exhibits bright green emission centered at 545 nm when excited by 381 nm ultraviolet light or 980 nm near-infrared light.The optimal doping concentration is found to be x=0.04.To quantify the temperature sensitivity of the phosphor,the fluorescence intensity ratio method was used.Within the temperature range of 298-473 K,the maximum relative sensitivities are 1.35%/K(298 K,381 nm)and 1.45%/K(298 K,980 nm),respectively.The maximum absolute sensitivities are 0.67%/K(473 K,381 nm)and 0.69%/K(473 K,980 nm),respectively.Finally,white light-emitting diodes(WLEDs)with a high colour index of Ra=82and a relatively low correlated colour temperature of CCT=5064 K are obtained by integrating the synthesized BaLaGaO_(4):0.04Er^(3+)green phosphor into warm WLEDs devices.These results suggest that Er^(3+)-activated BaLaGaO_(4)multifunctional phosphors hold considerable promise in the areas of optical temperature sensing and WLEDs phosphor conversion.展开更多
We demonstrate a case study of Ce-doped yttrium aluminum garnet(YAG)phosphor to illustrate a novel plasma route for the synthesis of multicomponent materials with addressing morphology and structural control.The prese...We demonstrate a case study of Ce-doped yttrium aluminum garnet(YAG)phosphor to illustrate a novel plasma route for the synthesis of multicomponent materials with addressing morphology and structural control.The presented strategy was started directly from liquid precursors without any precipitating agents,and an innovative growth mechanism was proposed to explain the formation of monodispersed spherical particles with an adjusted size distribution.Homogeneous elemental distribution close to that of liquid precursors was also achieved due to the thermal nonequilibrium effect in plasma.Benefiting from the structural feature of the obtained product,a low transformation temperature of 1100℃for YAG phase was obtained and final products exhibit the highest photoluminescence intensity with rather low Ce doping of 0.5 wt.%,together with excellent thermal stability of 92%preservation of initial emission at 473 K.This work well illustrates the advance of plasma strategy in formation of multicomponent com-pounds with excellent performances,and its potential for large-scale production due to the transient and in-flight synthesis process.展开更多
A blue-red dual-emitting phosphor,Na_(3)KMg_(7)(PO_(4))_(6):Eu^(2+),Mn^(2+)was developed in this study.Eu^(2+)acts as a sensitizer ion in Na_(3)KMg_(7)(PO_(4))_(6):Mn^(2+),which significantly improves the undesirable ...A blue-red dual-emitting phosphor,Na_(3)KMg_(7)(PO_(4))_(6):Eu^(2+),Mn^(2+)was developed in this study.Eu^(2+)acts as a sensitizer ion in Na_(3)KMg_(7)(PO_(4))_(6):Mn^(2+),which significantly improves the undesirable luminous efficiency of Mn^(2+).The energy transfer between Eu^(2+)and Mn^(2+)significantly boosts both internal quantum efficiency(IQE)and external quantum efficiency(EQE)of the phosphor,achieving values of 72.5%and 42.6%,respectively.Additionally,the phosphor demonstrates exceptional thermal stability,at150℃.maintaining 71.49%of its initial emission intensity.The emission spectrum of the phosphor closely matches the chlorophyll's absorption spectra,with similarities of 75.06%and 94.52%,respectively.This was further confirmed through a fabricated LED with a n-UV chip(395 nm).To further assess the potential for agritech applications,a light-conversion film incorporating the developed phosphor in PDMS glue was prepared.An outdoor cultivation trial with Chlorella showed that the algae's growth rate improves by 27.3%relative to a control group.These results reveal the significant potential of the Na_(3)KMg_(7)(PO_(4))_(6):Eu^(2+),Mn^(2+)phosphor for enhancing plant growth in practical applications.展开更多
To develop new up-conversion luminescent materials for non-contact optical thermometer with high sensitivity and temperature re solution,a battery of KBaGd(MoO_(4))_(3):Yb^(3+),Ho^(3+)phosphors were fabricated through...To develop new up-conversion luminescent materials for non-contact optical thermometer with high sensitivity and temperature re solution,a battery of KBaGd(MoO_(4))_(3):Yb^(3+),Ho^(3+)phosphors were fabricated through solid reaction process.The crystal structure,up-conversion luminescence,energy transfer,thermal stability and optical temperature sensing performances were studied in detail.Under 980 nm laser excitation,the KBaGd(MoO_(4))_(3):Yb^(3+),Ho^(3+)phosphor exhibits distinctive emission bands of Ho^(3+)at545,660,and 755 nm,and excellent illuminant performance.Based on the thermally coupled levels(TCLs)of Ho^(3+),both the relative sensitivity(S_(r))and absolute sensitivity(S_(a))display similar change trends,with the highest values of 6.73%/K(@298 K)and 5.69%/K(@298 K),respectively.Furthermore,the highest Saof 13.90%/K(@623 K)and the ultimate Srof 0.62%/K(@298 K)are achieved based on non-TCLs of Ho^(3+).Therefore,KBaGd(MoO_(4))_(3):Yb^(3+),Ho^(3+)phosphor is a promising candidate for self-referenced optical thermometry.展开更多
Phosphoric acid is a key ingredient in fertilizer production and contains many rare earth elements(REEs).Recovering REEs from phosphoric acid can prevent the accumulation of these elements in the soil and help bridge ...Phosphoric acid is a key ingredient in fertilizer production and contains many rare earth elements(REEs).Recovering REEs from phosphoric acid can prevent the accumulation of these elements in the soil and help bridge the gap between supply and demand.In this concern,a new material called Si-6G PAMAMPPAAM dendrimers modified silica gel terminated with phenylphosphonic acid-amide moieties was developed and its ability to adsorb Nd(Ⅲ)and Er(Ⅲ)from the phosphoric acid solution was investigated.K inetics and isotherm of the uptake process were investigated to explo re the so rption characte ristics.The attained results show that both metal ions exhibit the same adsorption performance,and the uptake process is depicted as a chemisorption,monolayer,uniform,and homogeneous process.The equilibrium state is achieved within 120 min,and the maximum uptake capacity is 16.7 mg Nd(Ⅲ)/g,and 14.0 mg Er(Ⅲ)/g.Sorption thermodynamics is an endothermic,spontaneous,and feasible uptake process.Nitric acid(1.0 mol/L)is found to be efficient for adsorbing about 94.3%and 92.5%of neodymium(Ⅲ)and erbium(Ⅲ)respectively,and the prepared Si-6G PAMAM-PPAAM demonstrates excellent stability over five consecutive sorption/desorption cycles.Preliminary tests on commercial phosphoric acid demonstrate that Si-6G PAMAM-PPAAM retains its effective REEs uptake from a complex comm ercial phosph oric acid solution.展开更多
Different reactive flame retardants have been extensively developed for vinyl ester resins(VERs),but very few of them can yield a flame-retardant resin that meets defined standards(e.g.UL-94 V-0 rating).In this work,p...Different reactive flame retardants have been extensively developed for vinyl ester resins(VERs),but very few of them can yield a flame-retardant resin that meets defined standards(e.g.UL-94 V-0 rating).In this work,phosphorous-containing 1-vinylimidazole salts(called VIDHP and VIDPP)were synthesized through the facile neutralization of the acid and 1-vinylimidazole.VIDHP and VIDPP were then applied as flame-retardant crosslinking agents of VERs,by which phosphorus-containing groups could be incorporated into the resin chain via ionic bonds.VIDHP/VER and VIDPP/VER showed a high curing activity and can be well cured in moderate temperatures.With 20 wt.%additions of VIDHP and VIDPP,VIDHP20/VER,and VIDPP20/VER presented a limiting oxygen index value of 29.7%and 28.4%,respectively,with the latter achieving a UL 94 V0 rating.In the cone calorimetric test,compared to the unmodified VERs,VIDPP20/VER exhibited large reductions in the peak heat release rate,total heat release rate,and total smoke release rate while VIDHP20/VER demonstrated comparatively inferior performance in terms of the heat release.VIDHP20/VER and VIDPP20/VER showed good thermal stability and presented a little lower glass transition temperature than the control sample.VIDPP with a low phosphorus oxidation state(+1)demonstrated high flame-retardant activities in the gaseous phase,whereas VIDHP with a high phosphorus oxidation state(+5)primarily exhibited efficacy in the condensed phase.展开更多
The significance of axial chiral compounds in asymmetric organic catalysis,functional materials,and pharmaceutical useful molecules has encouraged advancements in the atroposelective synthesis of such compounds.Herein...The significance of axial chiral compounds in asymmetric organic catalysis,functional materials,and pharmaceutical useful molecules has encouraged advancements in the atroposelective synthesis of such compounds.Herein,we report the first atroposelective construction of axially chiral N-aryl benzimidazoles catalyzed by a polymer-supported chiral phosphoric acid.A varied library of atropisomers has been synthesized in 30%-96%yield with 58%-98%enantiomeric excess(ee)under a straightforward reaction setup(without the use of molecular sieves).Notably,even after 12 cycles,the immobilized catalyst maintained its reactivity and selectivity(TON>540).展开更多
A comprehensive mechanistic study on the chiral phosphoric acid catalyzed an enantioselective asymmetric aza-pinacol rearrangement of 4-chloro-N-(2-(3'-hydroxy-1'-phenylspiro[cyclopentane-1,2'-indolin]-3&#...A comprehensive mechanistic study on the chiral phosphoric acid catalyzed an enantioselective asymmetric aza-pinacol rearrangement of 4-chloro-N-(2-(3'-hydroxy-1'-phenylspiro[cyclopentane-1,2'-indolin]-3'-yl)ethyl)(1a)is investigated at the M06-2X/6-311+G(d,p)level.Our computational results suggest that the whole catalytic cycle proceeds through dehydration of 1a,enantioselective aza-pinacol rearrangement,intramolecular cyclization and catalyst regeneration to deliver the fused indoline product.The aza-pinacol rearrangement is the key stereocontrolling step of the title reaction.The chiral catalyst controls the orientation of the transition states of the enantioselective step through two potential binding sites between the bifunctional chiral phosphate and the aza-ortho-xylylene intermediate.Moreover,theoretical studies identified that the multiple C—H…π,C—H…O,and C—H…N hydrogen bonds and N—H…O^(-)electrostatic interactions between the substrates and the arms as well as functional oxygen anion of the chiral catalyst(R)-4c play a crucial role in determining the stereochemical outcomes.And the strong N—H…O^(-)interaction in the major transition state was found to contribute to the high levels of enantioselectivity.Additionally,the predicted enantiomeric excess(ee)of 89%based on the 6.3 kJ·mol^(–1)energy difference between the enantioselective TS-2-major and TS-2-minor is in agreement with the experimental results of 90%.展开更多
All-inorganic reflective phosphor-in-glass film(PiGF) converter has garnered widespread attentions for high brightness laser-driven white lighting,while its poor color quality and low luminescence stability have been ...All-inorganic reflective phosphor-in-glass film(PiGF) converter has garnered widespread attentions for high brightness laser-driven white lighting,while its poor color quality and low luminescence stability have been inevitable roadblocks.Herein,the bicolor PiGF containing green-emitting Y3Al3.08Ga1.92O12:Ce3+(YAGG) and red-emitting CaAlSiN_(3):Eu^(2+)(CASN) phosphors bonded on Al2O3substrate was prepared for enabling high color quality laser-driven white lighting in reflective configuration.The bicolor PiGF has high quantum efficiency and good structure stability.By optimizing the CASN content,PiGF thickness and Al_(2)O_(3) content,the reflective bicolor PiGF based white laser diode(LD)displays good luminescence performance with a luminous flux of 451.5 lm and a luminous efficacy of142.3 lm/W and high color quality with a color rendering index(CRI) of 85.3 and a correlated color temperature(CCT) of 5177 K under the incident laser power of 3.15 W,and still has excellent luminescence and color stabilities(CRI and CCT) under the continuous laser excitation of 5.61 W,attributed to the good thermal conductivity and high reflectivity of Al_(2)O_(3) substrate and scattering enhancement effect of Al_(2)O_(3) particles.It can be foreseen that the reflective bicolor PiGF converter provides a promising strategy for enabling high quality laser-driven white lighting.展开更多
Nowadays,high-quality phosphor-converted white light-emitting diodes(pc-WLEDs)ought to include cyan-emitting phosphors allowing for full-spectrum light similar to sunlight.Herein,we report a garnetstructured Ce^(3+)-d...Nowadays,high-quality phosphor-converted white light-emitting diodes(pc-WLEDs)ought to include cyan-emitting phosphors allowing for full-spectrum light similar to sunlight.Herein,we report a garnetstructured Ce^(3+)-doped SrLu_(2)Ga_(1.5)Al_(2.5)SiO_(12)(SLGASO)phosphor that significantly compensates for the absence of cyan light,known as the"cyan cavity".The SLGASO host crystallizes into a cubic structure with the Ia3d space group.The cell parameters were determined using Rietveld refinement.Under430 nm blue excitation,SLGASO:Ce^(3+)emits intense cyan-green light in the 450-700 nm wavelength range.The representative SLGASO:0.07Ce^(3+)phosphor has an internal quantum efficiency(IQE)of 95.4%and excellent thermal stability,remaining 92.7%of its initial emission intensity at 152℃.After 155 d of immersion in water,the luminous intensity of SLGASO:0.07Ce^(3+)remains constant,confirming its waterproofness.Furthermore,a pc-WLED device with luminous efficiency(LE)of 101.58 lm/W,color rendering index(Ra)of 91,correlated color temperature(CCT)of 4536 K,and Commission Internationale de L'Eclairage(CIE)chromaticity coordinates of(0.3555,0.3390)was fabricated by combining asprepared cyan-green-emitting SLGASO:0.07Ce^(3+),yellow-emitting Y_(3)Al_(5)O_(12):Ce^(3+)(YAG:Ce^(3+)),and redemitting(Ca,Sr)AlSiN_(3):Eu^(2+)phosphors,as well as a 450 nm blue chip.These findings indicate that SLGASO:0.07Ce^(3+)phosphor can bridge the cyan gap and improve the performance of as-fabricated fullvisible-spectrum WLEDs.展开更多
基金supported by the National Natural Science Foundation of China(No.20876125)the Research Fund for the Doctoral Program of Higher Education(No.20096101110013)Northwest University Graduate Cross-discipline Funds(Nos.09YJC24 and 09YJC27)
文摘A novel up-converting phosphor,Na_xAl_yF_（x＋3y）/CaF2（0.3 〈 x 〈 0.5,0 〈 y 〈 0.1） composite,is prepared by a hydrothermal process at 180°C and an annealing treatment at 500℃.X-ray diffraction（XRD） pattern indicates that Na_xAl_yF_（x＋3y）/CaF_2 is a composite consisting of NaF,Na_3 AlF_6,and CaF_2.The up-conversion luminescence properties of this phosphor are investigated by fluorescence spectrometer.Results show that Na_xAl_yF_（x＋3y）/CaF_2 exhibits visible-to-ultraviolet up-conversion luminescence properties.The emission peaks at 316 and 336 nm are observed when excited by 610 nm,the luminescence lifetime of the emissions is great than 18 ms,and the internal fluorescence quantum yield is 4.2%.Additionally,the luminescent mechanism of this phosphor is also mentioned.
基金Part of this work related to UCP-LF CAA testing,received financial support from the University of Georgia Research Foundation,Inc.(Schistosomiasis Consortium for Operational Research and Evaluation[SCORE]project).
文摘Background:Methodological applications of the high sensitivity genus-specific Schistosoma CAA strip test,allowing detection of single worm active infections(ultimate sensitivity),are discussed for efficient utilization in sample pooling strategies.Besides relevant cost reduction,pooling of samples rather than individual testing can provide valuable data for large scale mapping,surveillance,and monitoring.Method:The laboratory-based CAA strip test utilizes luminescent quantitative up-converting phosphor(UCP)reporter particles and a rapid user-friendly lateral flow(LF)assay format.The test includes a sample preparation step that permits virtually unlimited sample concentration with urine,reaching ultimate sensitivity(single worm detection)at 100%specificity.This facilitates testing large urine pools from many individuals with minimal loss of sensitivity and specificity.The test determines the average CAA level of the individuals in the pool thus indicating overall worm burden and prevalence.When requiring test results at the individual level,smaller pools need to be analysed with the pool-size based on expected prevalence or when unknown,on the average CAA level of a larger group;CAA negative pools do not require individual test results and thus reduce the number of tests.Results:Straightforward pooling strategies indicate that at sub-population level the CAA strip test is an efficient assay for general mapping,identification of hotspots,determination of stratified infection levels,and accurate monitoring of mass drug administrations(MDA).At the individual level,the number of tests can be reduced i.e.in low endemic settings as the pool size can be increased as opposed to prevalence decrease.Conclusions:At the sub-population level,average CAA concentrations determined in urine pools can be an appropriate measure indicating worm burden.Pooling strategies allowing this type of large scale testing are feasible with the various CAA strip test formats and do not affect sensitivity and specificity.It allows cost efficient stratified testing and monitoring of worm burden at the sub-population level,ideally for large-scale surveillance generating hard data for performance of MDA programs and strategic planning when moving towards transmission-stop and elimination.
基金This work was supported by the National Natural Science Foundation of China under Grant No. 60378024.
文摘An optical biosensor with up-converting phosphor （UCP） marker is developed for the sensitive rapid immunoassay to the specific biomolecule. UCP can emit visible light when excited by infrared light. Through detecting and analyzing the content of UCP particles on the test strip after immunoreaction, the concentration of target analyte in the sample can be obtained. The detection sensitivity to plague IgG is better than 5 ng/ml; to plague FI-Ab is better than 100 pg/ml; to plague Yersinia pestis cell is better than 3 ×10^4 CFU/ml. Good linear response characteristics and an excellent correlation （R^2 ≥ 0.95） have been verified by quantitative detection results. In the practical application, detection results to 167 analytic samples have an excellent consistency with those obtained by reverse hemagglutination test. The up-converting phosphor technology （UPT） based biosensor has stable, reliable, and sensitive performances. It can meet the need of various bioassay applications.
基金support by the National Natural Science Foundation of Inner Mongolia (2022SHZR1885)Natural Science Foundation of Hebei province (E2022402101,E2022402105)。
文摘To completely recover valuable elements and reduce the amount of waste,the impact of phosphoric acid on the decomposition of rare earth,fluorine and phosphorus during cyclic leaching was studied based on the characteristics of low-tempe rature sulfuric acid deco mposition.When a single monazite was leached using 75 wt% H_(2)SO_(4) solution with phosphoric acid,the size and number of monazite particles in the washing slag gradually decrease with the increase in phosphoric acid content in the leaching solution.The monazite phase can hardly be found in the slag when the phosphoric acid content reaches 70 g/L,which indicates that phosphoric acid is favorable for monazite decomposition.The mixed rare earth concentrate was leached by 75 wt% H_(2)SO_(4) containing 70 g/L phosphoric acid,the mineral compositions of the washing slag are only gypsum and unwashed rare earth sulfuric acid.After cyclic leaching of75 wt% H_(2)SO_(4),the mineral compositions of the primary leaching washing slag are mainly undecomposed monazite,rare earth sulfate and calcium sulfate.However,monazite is not found in the mineral phase of the second and third leaching washing slag.The leaching rates of rare earth and phosphorus gradually increase with the increase in cyclic leaching times.In addition,the phosphoric acid content in the leaching solution increases with the increase in the number of cyclic leaching time.However,the rising trend decreases when the phosphoric acid content reaches 50 g/L by adsorption and crystallization of phosphoric acid.A small amount of water can be used to clean the leaching residue before washing to recover the more soluble phosphorus acid according to the difference of dissolution between phosphoric acid and rare earth sulfuric acid.
文摘The catalytic enantioselective electrophilic amination reaction has emerged as a highly efficient method for synthesizing diverse nitrogen-containing chiral molecules,with the development of various asymmetric catalysis systems.Chiral phosphoric acids(CPA)have been widely acknowledged as versatile chiral organocatalysts since it was first discovered in 2004,finding application in catalyzing diverse asymmetric reactions.A comprehensive overview of recent advances in CPA-catalyzed asymmetric electrophilic amination reactions using different N-electrophilic reagents,including azo reagents,aryldiazonium salts,and imine derivatives,is presented.Furthermore,insights into future developments in this field are offered.
基金financially supported by the Caiyun Postdoctoral Innovation Project(No.C615300504089)Yunnan Fundamental Research Project(No.202401AS070128)National Natural Science Foundation of China(No.22165031).
文摘Bifunctional applications in solid state lighting and optical thermometry are attractive in the optical field.Despite Eu^(3+)doped phosphors are widely used in white-LEDs,phosphors with high temperature sensitivity remain rare.Herein,NaLnTe_(2)O_(7):Eu^(3+)(Ln=Y and Gd)phosphors were synthesized using a rapid microwave-assisted solidstate(MASS)method to fulfill these applications.Under 395 nm excitation,NaLnTe_(2)O_(7):Eu^(3+)exhibit the characteristic ^(5)D_(0)→^(7)F_(J)(J=1–4)transitions of Eu^(3+).Substituting Gd^(3+) for Y^(3+) enhances the luminescence by approximately 2.42 times.Structural analyses reveal that the improved luminescent properties are attributed to the more distorted and appropriate coordination environment in NaGdTe_(2)O_(7):Eu^(3+).Finally,white-LEDs using NaGdTe_(2)O_(7):Eu^(3+)as the red-component produce white light with high Ra of 89.Furthermore,the distinct thermal responses of the ^(5)D_(0)→^(7)F_(J) transitions enable NaLnTe_(2)O_(7):Eu^(3+)to function as temperature sensors via fluorescence intensity ratio(FIR)strategy.NaYTe_(2)O_(7):Eu^(3+)possesses the maximum relative/absolute sensitivity of 1.45%/15.93%K^(-1),whereas NaGdTe_(2)O_(7):Eu^(3+)achieves the maximum relative/absolute sensitivity of 1.53%/30.24% K^(-1).This work highlights the significance of cationic substitution in enhancing luminescent properties for multifunctional applications.
基金financed by the National Research Foundation of Ukraine(Project No.2022.01/0168).
文摘The work deals with cellulose paper filled with nanocellulose and SrAl_(2)O_(4):Eu,Dy oxide phosphor.It was found that both nanocellulose and oxide improve the tensile strength of the composites obtained.The samples with the oxide demonstrate a long-lasting photoluminescence(PL)under sunlight and ultra-violet(UV)illumination.Room-temperature the PL spectra reveal a wide multicomponent band spreading over all the visible spectral regions.The short-wavelength part of the band is ascribed to the cellulose-related luminescence,while the long-wavelength PL component with maxima near 540 nm corresponds to the luminescence of the SrAl_(2)O_(4):Eu,Dy phosphor.The dependency of the PL intensity on oxide concentration suggests the reabsorption of cellulose emission by the oxide and vice versa.The study of the dielectric properties of composite papers shows the presence of dielectric relaxations at low temperatures(T~−50℃).Similar cellulose materials to those studied can be considered as alternatives for artificial petroleum-based polymers.Low cost,eco-friendliness,biocompatibility,and the simplicity of recycling are among the main advantages of these materials.They are produced from the cellulose which is one of the most abundant renewable materials in nature.The data on the mechanical,dielectric,and optical properties indicate that the papers studied can be used in flexible lighting devices,WLEDs,coating,markers,labels,etc.
基金Project supported by the National Natural Science Foundation of China(12074373,12474415,U22A20139)the Major Science and Technology Project of Anhui Province(2021e03020007)+1 种基金the Developing Project of Science and Technology of Jilin Province(the Natural Science Foundation,20210101473JC)the Key Laboratory of Advanced Structural Materials(ASM-202205)。
文摘Broadband near-infrared(NIR)phosphor-conve rted light-emitting diode(pc-LED)is a new generation of light source for spectroscopy applications.Current studies generate a broad continuous NIR spectrum to promise the detection of a wide range of substances.This paper reports a discontinuous NIR spectral distribution peaking at 760 and 1400 nm,respectively,by co-doping Cr^(3+)and Ni^(2+)ions into CaLu_(2)Mg_(2)Si_(3)O_(12)garnet.The benefit of such a discontinuous spectrum is its ability to prevent energy waste in specific applications,such as moisture(freshness)and hemoglobin detection,where only spectral bands near 750 and 1500 nm are required.The discontinuous spectrum is attributed to the ene rgy transfer from Cr^(3+)to Ni^(2+)ions.The NIR pc-LED fabricated by the new phosphor shows photoelectric efficiency of 9.12%@10 mA and NIR output power of 11.44 mW@100 mA.The NIR pc-LED also performs well when measuring alcohol solution where only a discontinuous spectrum is needed.These results highlight the potential of NIR phosphors with a discontinuous spectrum across a broad 700-1600 nm range.
基金financially supported by the Natural Science Foundation of China(Nos.22208214,22005190,and 21938005)the Science&Technology Commission of Shanghai Municipality(Nos.20QB1405700,and 19DZ1205500)Zhejiang Key Research and Development Program(No.2020C01128)
文摘Sodium-ion batteries(SIBs) are promising electrochemical energy storage systems as lithium-ion batteries by virtue of their similar chemical properties and natural abundance and availability.However,the ionic radius of Na^(+)is larger than that of Li^(+),leading to challenges in its insertion/extraction at anode side.As a class of anode materials,phosphorus allotropes(PAs,red,and black) and metal phosphides(MPs) have shown great prospects because of high theoretical gravimetric/volumetric capacity,high carrier mobility,and suitable redox potential.In this review,recent developments in the studies of PAs and MPs with particular emphasis on understanding sodium storage mechanisms,developing novel synthesis strategies,and performance validations have been manifested valuable solutions to address these challenges.We begin with the introduction and classification of the macroscopic sodiation mechanisms of PAs and MPs,and the various fabrication strategies of PAs and MPs are comprehensively summarized in second section.The third section thoroughly reviews the progresses on PAs and MPs-based advanced materials for their application in SIBs.Finally,we also discuss the significant challenges and outline a roadmap for future research directions.
基金funded by the Launch Fund of Hainan University High Level Talent,China(RZ2100003226)the National Natural Science Foundation of China(NSFC-31860728).
文摘This investigation evaluated the impact of as-is biochar(BC)and phosphorous(P)-loaded biochar(PBC)(3%)on the growth and biochemical characteristics of rice under exposure to vanadium(V)(60 mg L^(-1)).The results indicate that rice plants exposed to a V-only treatment experienced declines in several growth parameters.Conversely,the inclusion of BC and PBC caused noteworthy increases in physiological traits.PBC performed well in stress environments.Specifically,the shoot and root fresh weights increased by 82.86 and 53.33%,respectively,when compared to the V-only treatment.In addition,the SPAD chlorophyll of the shoot increased by 13.05%relative to the V-amended plants.Moreover,including BC and PBC improved the antioxidant enzyme traits of plant shoot and root,such as significant increases in superoxide dismutase(SOD by 56.11 and 117.35%),catalase(CAT by 34.19 and 35.77%),and peroxidase(POD by 25.90 and 18.74%)when compared to V-only amended plants,respectively.These findings strongly suggest that the application of BC and PBC can trigger biochemical pathways that facilitate biomass accumulation in meristematic cells.However,further investigations are required to elucidate the underlying mechanisms responsible for this growth promotion.
基金supported by the National Natural Science Foundation of China(52403403)Guizhou Provincial Basic Research Program(Natural Science)(Qian ke he ji chu-ZK2024 YiBan 095)。
文摘Er^(3+)-doped BaLaGaO_(4)green phosphors was synthesized through a high-temperature solid-state reaction technique.The phase structure and morphology test results of the phosphor indicate that the BaLaGaO_(4)material was successfully synthesized and Er^(3+)ions were successfully doped into the main lattice.This doping does change the basic structure of the crystal.BaLaGaO_(4):Er^(3+)phosphor exhibits bright green emission centered at 545 nm when excited by 381 nm ultraviolet light or 980 nm near-infrared light.The optimal doping concentration is found to be x=0.04.To quantify the temperature sensitivity of the phosphor,the fluorescence intensity ratio method was used.Within the temperature range of 298-473 K,the maximum relative sensitivities are 1.35%/K(298 K,381 nm)and 1.45%/K(298 K,980 nm),respectively.The maximum absolute sensitivities are 0.67%/K(473 K,381 nm)and 0.69%/K(473 K,980 nm),respectively.Finally,white light-emitting diodes(WLEDs)with a high colour index of Ra=82and a relatively low correlated colour temperature of CCT=5064 K are obtained by integrating the synthesized BaLaGaO_(4):0.04Er^(3+)green phosphor into warm WLEDs devices.These results suggest that Er^(3+)-activated BaLaGaO_(4)multifunctional phosphors hold considerable promise in the areas of optical temperature sensing and WLEDs phosphor conversion.
基金supported by the National Natu-ral Science Foundation of China(No.52174342)the Beijing Nat-ural Science Foundation(No.2232044)the Beijing Munic-ipal Education Commission Research Plan General Project(No.KM202410005009).
文摘We demonstrate a case study of Ce-doped yttrium aluminum garnet(YAG)phosphor to illustrate a novel plasma route for the synthesis of multicomponent materials with addressing morphology and structural control.The presented strategy was started directly from liquid precursors without any precipitating agents,and an innovative growth mechanism was proposed to explain the formation of monodispersed spherical particles with an adjusted size distribution.Homogeneous elemental distribution close to that of liquid precursors was also achieved due to the thermal nonequilibrium effect in plasma.Benefiting from the structural feature of the obtained product,a low transformation temperature of 1100℃for YAG phase was obtained and final products exhibit the highest photoluminescence intensity with rather low Ce doping of 0.5 wt.%,together with excellent thermal stability of 92%preservation of initial emission at 473 K.This work well illustrates the advance of plasma strategy in formation of multicomponent com-pounds with excellent performances,and its potential for large-scale production due to the transient and in-flight synthesis process.
基金supported by the Department of Industry and Information Technology of Gansu Province(2024 Provincial Key Talent Program)the National Natural Science Foundation of China(U22A20136)。
文摘A blue-red dual-emitting phosphor,Na_(3)KMg_(7)(PO_(4))_(6):Eu^(2+),Mn^(2+)was developed in this study.Eu^(2+)acts as a sensitizer ion in Na_(3)KMg_(7)(PO_(4))_(6):Mn^(2+),which significantly improves the undesirable luminous efficiency of Mn^(2+).The energy transfer between Eu^(2+)and Mn^(2+)significantly boosts both internal quantum efficiency(IQE)and external quantum efficiency(EQE)of the phosphor,achieving values of 72.5%and 42.6%,respectively.Additionally,the phosphor demonstrates exceptional thermal stability,at150℃.maintaining 71.49%of its initial emission intensity.The emission spectrum of the phosphor closely matches the chlorophyll's absorption spectra,with similarities of 75.06%and 94.52%,respectively.This was further confirmed through a fabricated LED with a n-UV chip(395 nm).To further assess the potential for agritech applications,a light-conversion film incorporating the developed phosphor in PDMS glue was prepared.An outdoor cultivation trial with Chlorella showed that the algae's growth rate improves by 27.3%relative to a control group.These results reveal the significant potential of the Na_(3)KMg_(7)(PO_(4))_(6):Eu^(2+),Mn^(2+)phosphor for enhancing plant growth in practical applications.
基金supported by the National Natural Science Foundation of China(61865003)。
文摘To develop new up-conversion luminescent materials for non-contact optical thermometer with high sensitivity and temperature re solution,a battery of KBaGd(MoO_(4))_(3):Yb^(3+),Ho^(3+)phosphors were fabricated through solid reaction process.The crystal structure,up-conversion luminescence,energy transfer,thermal stability and optical temperature sensing performances were studied in detail.Under 980 nm laser excitation,the KBaGd(MoO_(4))_(3):Yb^(3+),Ho^(3+)phosphor exhibits distinctive emission bands of Ho^(3+)at545,660,and 755 nm,and excellent illuminant performance.Based on the thermally coupled levels(TCLs)of Ho^(3+),both the relative sensitivity(S_(r))and absolute sensitivity(S_(a))display similar change trends,with the highest values of 6.73%/K(@298 K)and 5.69%/K(@298 K),respectively.Furthermore,the highest Saof 13.90%/K(@623 K)and the ultimate Srof 0.62%/K(@298 K)are achieved based on non-TCLs of Ho^(3+).Therefore,KBaGd(MoO_(4))_(3):Yb^(3+),Ho^(3+)phosphor is a promising candidate for self-referenced optical thermometry.
文摘Phosphoric acid is a key ingredient in fertilizer production and contains many rare earth elements(REEs).Recovering REEs from phosphoric acid can prevent the accumulation of these elements in the soil and help bridge the gap between supply and demand.In this concern,a new material called Si-6G PAMAMPPAAM dendrimers modified silica gel terminated with phenylphosphonic acid-amide moieties was developed and its ability to adsorb Nd(Ⅲ)and Er(Ⅲ)from the phosphoric acid solution was investigated.K inetics and isotherm of the uptake process were investigated to explo re the so rption characte ristics.The attained results show that both metal ions exhibit the same adsorption performance,and the uptake process is depicted as a chemisorption,monolayer,uniform,and homogeneous process.The equilibrium state is achieved within 120 min,and the maximum uptake capacity is 16.7 mg Nd(Ⅲ)/g,and 14.0 mg Er(Ⅲ)/g.Sorption thermodynamics is an endothermic,spontaneous,and feasible uptake process.Nitric acid(1.0 mol/L)is found to be efficient for adsorbing about 94.3%and 92.5%of neodymium(Ⅲ)and erbium(Ⅲ)respectively,and the prepared Si-6G PAMAM-PPAAM demonstrates excellent stability over five consecutive sorption/desorption cycles.Preliminary tests on commercial phosphoric acid demonstrate that Si-6G PAMAM-PPAAM retains its effective REEs uptake from a complex comm ercial phosph oric acid solution.
基金supported by the National Natural Science Foundation of China(Grant Nos.51991351 and51903132)the Young Elite Scientist Sponsorship Program by CAST(No.2022QNRC001).
文摘Different reactive flame retardants have been extensively developed for vinyl ester resins(VERs),but very few of them can yield a flame-retardant resin that meets defined standards(e.g.UL-94 V-0 rating).In this work,phosphorous-containing 1-vinylimidazole salts(called VIDHP and VIDPP)were synthesized through the facile neutralization of the acid and 1-vinylimidazole.VIDHP and VIDPP were then applied as flame-retardant crosslinking agents of VERs,by which phosphorus-containing groups could be incorporated into the resin chain via ionic bonds.VIDHP/VER and VIDPP/VER showed a high curing activity and can be well cured in moderate temperatures.With 20 wt.%additions of VIDHP and VIDPP,VIDHP20/VER,and VIDPP20/VER presented a limiting oxygen index value of 29.7%and 28.4%,respectively,with the latter achieving a UL 94 V0 rating.In the cone calorimetric test,compared to the unmodified VERs,VIDPP20/VER exhibited large reductions in the peak heat release rate,total heat release rate,and total smoke release rate while VIDHP20/VER demonstrated comparatively inferior performance in terms of the heat release.VIDHP20/VER and VIDPP20/VER showed good thermal stability and presented a little lower glass transition temperature than the control sample.VIDPP with a low phosphorus oxidation state(+1)demonstrated high flame-retardant activities in the gaseous phase,whereas VIDHP with a high phosphorus oxidation state(+5)primarily exhibited efficacy in the condensed phase.
基金supported by Shenzhen Science and Technology Research(Nos.JSGG20201103153807021,GXWD20220811173736002,KCXFZ20230731094904009)the Fundamental Research Funds for the Central Universities,Sun Yat-sen University(No.24qnpy060)+2 种基金Natural Science Foundation of Guangdong Province(No.2021A1515110366)National Natural Science Foundation of China(Nos.22302048,82204231,22275146)Shenzhen Key Laboratory of Advanced Functional Carbon Materials Research and Comprehensive Application。
文摘The significance of axial chiral compounds in asymmetric organic catalysis,functional materials,and pharmaceutical useful molecules has encouraged advancements in the atroposelective synthesis of such compounds.Herein,we report the first atroposelective construction of axially chiral N-aryl benzimidazoles catalyzed by a polymer-supported chiral phosphoric acid.A varied library of atropisomers has been synthesized in 30%-96%yield with 58%-98%enantiomeric excess(ee)under a straightforward reaction setup(without the use of molecular sieves).Notably,even after 12 cycles,the immobilized catalyst maintained its reactivity and selectivity(TON>540).
基金financially supported by the National Natural Science Foundation of China(21873018,21573036,and21603028)the open project of the Jilin Province Key Laboratory of Organic Functional Molecular Design&Synthesis(130028655)the Northeast Normal University Research Frontier Exploration Program(XDFZ202501)
文摘A comprehensive mechanistic study on the chiral phosphoric acid catalyzed an enantioselective asymmetric aza-pinacol rearrangement of 4-chloro-N-(2-(3'-hydroxy-1'-phenylspiro[cyclopentane-1,2'-indolin]-3'-yl)ethyl)(1a)is investigated at the M06-2X/6-311+G(d,p)level.Our computational results suggest that the whole catalytic cycle proceeds through dehydration of 1a,enantioselective aza-pinacol rearrangement,intramolecular cyclization and catalyst regeneration to deliver the fused indoline product.The aza-pinacol rearrangement is the key stereocontrolling step of the title reaction.The chiral catalyst controls the orientation of the transition states of the enantioselective step through two potential binding sites between the bifunctional chiral phosphate and the aza-ortho-xylylene intermediate.Moreover,theoretical studies identified that the multiple C—H…π,C—H…O,and C—H…N hydrogen bonds and N—H…O^(-)electrostatic interactions between the substrates and the arms as well as functional oxygen anion of the chiral catalyst(R)-4c play a crucial role in determining the stereochemical outcomes.And the strong N—H…O^(-)interaction in the major transition state was found to contribute to the high levels of enantioselectivity.Additionally,the predicted enantiomeric excess(ee)of 89%based on the 6.3 kJ·mol^(–1)energy difference between the enantioselective TS-2-major and TS-2-minor is in agreement with the experimental results of 90%.
基金Project supported by the Science and Technology Project of Shenzhen City (JSGG20210802154213040)the Guangdong Basic and Applied Basic Research Foundation (2024A1515010001)the Shenzhen Postdoctoral Research Funding Project。
文摘All-inorganic reflective phosphor-in-glass film(PiGF) converter has garnered widespread attentions for high brightness laser-driven white lighting,while its poor color quality and low luminescence stability have been inevitable roadblocks.Herein,the bicolor PiGF containing green-emitting Y3Al3.08Ga1.92O12:Ce3+(YAGG) and red-emitting CaAlSiN_(3):Eu^(2+)(CASN) phosphors bonded on Al2O3substrate was prepared for enabling high color quality laser-driven white lighting in reflective configuration.The bicolor PiGF has high quantum efficiency and good structure stability.By optimizing the CASN content,PiGF thickness and Al_(2)O_(3) content,the reflective bicolor PiGF based white laser diode(LD)displays good luminescence performance with a luminous flux of 451.5 lm and a luminous efficacy of142.3 lm/W and high color quality with a color rendering index(CRI) of 85.3 and a correlated color temperature(CCT) of 5177 K under the incident laser power of 3.15 W,and still has excellent luminescence and color stabilities(CRI and CCT) under the continuous laser excitation of 5.61 W,attributed to the good thermal conductivity and high reflectivity of Al_(2)O_(3) substrate and scattering enhancement effect of Al_(2)O_(3) particles.It can be foreseen that the reflective bicolor PiGF converter provides a promising strategy for enabling high quality laser-driven white lighting.
基金supported by the National Natural Science Foundations of China(21801254,52002411,52272174,22205017,U1301242)China Postdoctoral Science Foundation(2022M720400,2023M743978)+1 种基金Specialized Research Fund for the Doctoral Program of Higher Education of China(20130171130001)the Ministry of Science,Technological Development,and Innovation of the Republic of Serbia(451-03-66/2024-03/200017)。
文摘Nowadays,high-quality phosphor-converted white light-emitting diodes(pc-WLEDs)ought to include cyan-emitting phosphors allowing for full-spectrum light similar to sunlight.Herein,we report a garnetstructured Ce^(3+)-doped SrLu_(2)Ga_(1.5)Al_(2.5)SiO_(12)(SLGASO)phosphor that significantly compensates for the absence of cyan light,known as the"cyan cavity".The SLGASO host crystallizes into a cubic structure with the Ia3d space group.The cell parameters were determined using Rietveld refinement.Under430 nm blue excitation,SLGASO:Ce^(3+)emits intense cyan-green light in the 450-700 nm wavelength range.The representative SLGASO:0.07Ce^(3+)phosphor has an internal quantum efficiency(IQE)of 95.4%and excellent thermal stability,remaining 92.7%of its initial emission intensity at 152℃.After 155 d of immersion in water,the luminous intensity of SLGASO:0.07Ce^(3+)remains constant,confirming its waterproofness.Furthermore,a pc-WLED device with luminous efficiency(LE)of 101.58 lm/W,color rendering index(Ra)of 91,correlated color temperature(CCT)of 4536 K,and Commission Internationale de L'Eclairage(CIE)chromaticity coordinates of(0.3555,0.3390)was fabricated by combining asprepared cyan-green-emitting SLGASO:0.07Ce^(3+),yellow-emitting Y_(3)Al_(5)O_(12):Ce^(3+)(YAG:Ce^(3+)),and redemitting(Ca,Sr)AlSiN_(3):Eu^(2+)phosphors,as well as a 450 nm blue chip.These findings indicate that SLGASO:0.07Ce^(3+)phosphor can bridge the cyan gap and improve the performance of as-fabricated fullvisible-spectrum WLEDs.
