White light illumination is essential in daily life,however,the substantial amount of blue light it contains can damage human eyes.Therefore,it is important to block this high-energy blue light to protect visual healt...White light illumination is essential in daily life,however,the substantial amount of blue light it contains can damage human eyes.Therefore,it is important to block this high-energy blue light to protect visual health.In this study,yellow-emitting carbon dots(CDs)with a quantum yield exceeding 94%were synthesized using citric acid and urea.These CDs effectively absorb blue light.By incorporating them into polystyrene,multiple films termed CDs-based blue light blocking films(CBFs)were developed,each offering different levels of blue light absorption.These CBFs exhibited excellent transparency and efficient blue light filtering capabilities.This study highlights the potential of high quantum yield CDs,which specifically absorb blue light,as foundational materials for developing light-blocking solutions against highenergy short-wavelength light.展开更多
The exploitation of a highly selective and sensitive probe to detect both cancer marker and metal ion is of great importance.In this work,the "one stone two bird" agent of 1,10-phenanthroline(phen) is design...The exploitation of a highly selective and sensitive probe to detect both cancer marker and metal ion is of great importance.In this work,the "one stone two bird" agent of 1,10-phenanthroline(phen) is designed to disrupt the polymeric lanthanide MOFs(LnMOFs,[Ln(CHO_(2))_(3)]n,Ln=Tb,la;Eu,1 b,CHO_(2)=formic acid) {[Ln(CHO_(2))_(4)·(C_(2) H_(8) N)]n,Ln=Y,2 a;Gd,2 b;Dy,2 c,C_(2)H_(8) N=dimethylamine}) into a soluble mononuclear species [Ln(phen)_(2)(NO_(3))_(3),Ln=Tb,3 a;Eu,3 b] as well as to provide an antenna for efficient photons absorption,resulting in an ultra-high luminescence quantum yield(QY,90%) europium complex.The luminescence QY is among the highest record of monomeric(zero-dimensional) lanthanide complexes.Furthermore,mononuclear Tb3+complex(3 a) functions as a multiplex sensor towards both Fe^(2+)and cancer marker of 5-hydroxyindole-3-acetic acid(5-HIAA).Importantly,the limit of detection(LOD)for sensing 5-HIAA is an ultra-sensitive value of 1 × 10 s mol/L,which is even lower than that necessary for the early diagnosis of carcinoid tumors.More interestingly,sensing results in simulated urine reveals that 3 a has potential application for early diagnosis in the clinic.展开更多
Long-emission carbon dots(CDs) is triggering immense enthusiasm on account of their intrinsic merits of high chemical stability and excellent optical properties.In this study,a facile and rapid approach was developed ...Long-emission carbon dots(CDs) is triggering immense enthusiasm on account of their intrinsic merits of high chemical stability and excellent optical properties.In this study,a facile and rapid approach was developed for the preparation of barium-doped carbon dots(Ba-CDs) with yellow fluo rescence emission and high quantum yields.Surface chemistry and the chemical architecture of the Ba-CDs was revealed under various spectroscopic methods.This work provides more insights into the effects of charge transfer caused by Ba heteroatoms,which is considered as the most challenging step in the investigation on luminescence mechanism.Remarkably,the prepared Ba-CDs were successfully applied as fluorescent probes in the detection of trace water in organic solvents(ethanol,isopropanol,acetone,tetrahydrofuran).Comparing with traditional fluorescent probes for water detection in organic solvents,Ba-CDs detection provides a more sensitive,much faster and more economical approach.展开更多
The major cytotoxic agent with most current photosensitizers used in photodynamic therapy(PDT)is widely believed to be singlet oxygen(^(1)O_(2)).Determination of the ^(1)O_(2) quantum yields for porphyrin-based photos...The major cytotoxic agent with most current photosensitizers used in photodynamic therapy(PDT)is widely believed to be singlet oxygen(^(1)O_(2)).Determination of the ^(1)O_(2) quantum yields for porphyrin-based photosensitizers,including hematoporphyrin derivative(HiPorfin),hematoporphyrin monomethyl ether(HMME)and photocarcinorin(PsD-007)in air-saturated dimethylformamide(DMF)solutions were performed by the direct measurement of their near-infrared luminescence.In addition,^(1)O_(2) quencher sodium azide was employed to confirm the ^(1)O_(2) generation from the investigated photosensitizers.The maximal ^(1)O_(2) luminescence occurs at about 1280 nm with full width at half maximum of 30 nm.The ^(1)O_(2) quantum yields were found to be 0.61±0.03,0.60±0.02 and 0.59±0.03 for HiPorfin,HMME and PsD-007,respectively.These results provide that these porphyrin-based photosensitizers produce ^(1)O_(2) under irradiation,which is of significance for the study of their photodynamic action in PDT.展开更多
A series of Tb^3+ mono-doped and Ce^3+-Tb^3+ co-doped Sr3Gd2(Si3O9)2 phosphors with high thermal stability and quantum yields were successfully prepared via the solid state reaction. The as-prepared Sr3Gd2(Si3O9)2:Tb^...A series of Tb^3+ mono-doped and Ce^3+-Tb^3+ co-doped Sr3Gd2(Si3O9)2 phosphors with high thermal stability and quantum yields were successfully prepared via the solid state reaction. The as-prepared Sr3Gd2(Si3O9)2:Tb^3+ samples showed broad excitation spectrum from 250 to 400 nm and presented characteristic emission transitions ^5D4→^7FJ(J=6, 5, 4, 3) of Tb^3+ under 313 nm excitation, which were located at about 488, 541, 584 and 620 nm. The emission intensities of Tb^3+ rose steadily in Sr3Gd2(Si3O9)2 host with the increase of Tb^3+ concentration even though Gd^3+ ions were completely replaced by Tb^3+ ions. The Ce^3+ ion as a sensitizer could efficiently improve the performance of Tb^3+ ion. First, with Ce^3+ co-doping, the excitation spectrum of Tb^3+ monitored at 541 nm showed a similar band that responds to the violet emission of Ce^3+ monitored at 416 nm. Second, the quantum yields of Sr3Gd2(Si3O9)2:Tb^3+ phosphors could be enhanced from 26.6% to 80.2% by co-doping Ce^3+. Finally, the co-doping of Ce^3+ was also effective to improve the thermal stability of Sr3Gd2(Si3O9)2:Tb^3+. As the temperature rose to 150 oC, the emission intensity of Tb^3+ remained at about 83.6% of that measured at room temperature, which was better than the commercial YAG:Ce phosphor in terms of their thermal quenching properties. These results indicated that the as-prepared Sr3Gd2(Si3O9)2:Tb^3+,Ce^3+ samples could be used as green emission phosphors for possible applications in near ultraviolet based WLEDs.展开更多
The luminescent properties of two Eu3＋ compounds based on quinoline-2-car- boxylic acid （Hqc）, [Na2Eu2（qc）6（CH3COO）2（H2O）4].2DMF （1） and [Eu2（qc）6（H2O）6].3H2O （2）, as well as their syntheses and struc...The luminescent properties of two Eu3＋ compounds based on quinoline-2-car- boxylic acid （Hqc）, [Na2Eu2（qc）6（CH3COO）2（H2O）4].2DMF （1） and [Eu2（qc）6（H2O）6].3H2O （2）, as well as their syntheses and structures are reported. Both compounds are formed by slow evaporation at room temperature and exhibit zero dimensional dinuclear structures. It is worth mentioning that a 4.5-fold enhancement in luminescent quantum yield is achieved by reducing the nonradiative deactivation, through which the quantum yield increases remarkably to 67.62% for 1 compared with 12.18% for 2.展开更多
Gdo.9xRxEUo.lOOH （R=Y, La） crystals were synthesized by a flux method using a mixture of NaOH and KOH as the flux. X-ray diffraction data were well refined using the Rietveld method assuming that the crystals had a ...Gdo.9xRxEUo.lOOH （R=Y, La） crystals were synthesized by a flux method using a mixture of NaOH and KOH as the flux. X-ray diffraction data were well refined using the Rietveld method assuming that the crystals had a monoclinic structre belonging to the P21/m space group. The unit cell volumes of the Gdo.9 xLaxEuo.OOH crystals increased with increasing x, whereas those of Gdo.9-xYxEUo.lOOH decreased with increasing x. The Commission Internationale de IEclairage （CIE） chromaticity coordinates of Gdo.9 xRxEUo.lOOH （R=Y, La） crystals were located in the red region and were nearly constant over the range ofx values considered. The fluorescence quantum yield Dr monotonically decreased with increasing x regardless of the ionic radii of the substitute ions. The fact that the Dr value of Lao.9EuoAOOH was greater than that of Gdo.gEUo.lOOH indicated that the observed decrease in the values of the Gdo.9-,LaxEuo.1OOH crystals up to x=0.3 could not be attributed to an increase in the distance between Eu3＋ ions or to a decrease in the Gd3＋ content. The decrease might be due to an increase of killer centers introduced by elemental substitutions with the larger ion.展开更多
The fluorescently labelled polymers including pyrene-labelled polystyrene(PyPS) and pyrene-labelled poly(methyl methacrylate)(PyPMMA) with narrow molecular weight distributions were synthesized by the atom transfer ra...The fluorescently labelled polymers including pyrene-labelled polystyrene(PyPS) and pyrene-labelled poly(methyl methacrylate)(PyPMMA) with narrow molecular weight distributions were synthesized by the atom transfer radical copolymerization(ATRCP) of styrene or methyl methacrylate with 1-pyrenemethyl methacrylate(PyMMA). The ultrathin PyPS and PyPMMA films with the thickness ranging from 30 nm to 400 nm supported on the quartz slides were prepared by spin-coating. The fluorescent quantum yield(QY) of the pyrene probe in the ultrathin polymer films was investigated by the photoluminescence spectrometer using an integrating sphere detector. The QY decreased with the reduction of film thickness in the sub-200 nm range.展开更多
Theoretical dependence of the quantum yields on the size of Agnano-particle distribution from 0.8 nm to 37 nm embedded in BaOsemiconductor is discussed. The calculation results show that theincrease in Ag nano-particl...Theoretical dependence of the quantum yields on the size of Agnano-particle distribution from 0.8 nm to 37 nm embedded in BaOsemiconductor is discussed. The calculation results show that theincrease in Ag nano-particle diameter leads to the increase of thequantum yield threshold and the emergence of the rough Gaussian form,the results also shown that the greater increase in Ag nano-particlediameter causes the emergence of the exact Gaussian form and makesthe peaks rise up.展开更多
Eu3+-doped gadolinium oxyhydroxide Gd1-xEuxOOH crystals were synthesized by the flux method. The X-ray diffraction data for the crystals were well refined assuming a monoclinic structure with the P21/m space group. Gd...Eu3+-doped gadolinium oxyhydroxide Gd1-xEuxOOH crystals were synthesized by the flux method. The X-ray diffraction data for the crystals were well refined assuming a monoclinic structure with the P21/m space group. Gd1-xEuxOOH (x ≤ 0.2) crystals showed strong red emission, and the highest fluorescence quantum yield (Φf) was 0.27, obtained for x = 0.10. Φf decreased rapidly as the Eu3+ content x increased above 0.2, owing to concentration quenching. Analysis with a percolation model indicated three-dimensional energy transfer between the Eu3+ ions.展开更多
The alpine meadow is widely distributed on the Tibetan Plateau with an area of about 1.2×106km2.Damxung County,located in the hinterland of the Tibetan Plateau,is the place covered with this typical vegetation.An...The alpine meadow is widely distributed on the Tibetan Plateau with an area of about 1.2×106km2.Damxung County,located in the hinterland of the Tibetan Plateau,is the place covered with this typical vegetation.An open-path eddy covariance system was set up in Damxung rangeland station to measure the carbon flux of alpine meadow from July to October,2003.The continuous carbon flux data were used to analyze the relationship between net ecosystem carbon dioxide exchange(NEE)and photosynthetically active radiation(PAR),as well as the seasonal patterns of apparent quantum yield(α)and maximum ecosystem assimilation(Pmax).Results showed that the daytime NEE fitted fairly well with the PAR in a rectangular hyperbola function,withαdeclining in the order of peak growth period(0.0244μmolCO2·μmol-1PAR)>early growth period>seed maturing period>withering period(0.0098μmolCO2·μmol-1PAR).The Pmax did not change greatly during the first three periods,with an average of 0.433 mgCO2·m-2·s-1,i.e.9.829μmolCO2·m-2·s-1.However,during the withering period,Pmax was only 0.35 mgCO2·m-2·s-1,i.e.7.945μmolCO2·m-2·s-1.Compared with other grassland ecosystems,theαof the Tibetan Plateau alpine meadow ecosystem was much lower.展开更多
Zero-dimensional(0D)lead-free all-inorganic metal halides have emerged as next-generation photoluminescent(PL)materials in recent years because of their extraordinary PL properties,non-toxicity,and high stability.Here...Zero-dimensional(0D)lead-free all-inorganic metal halides have emerged as next-generation photoluminescent(PL)materials in recent years because of their extraordinary PL properties,non-toxicity,and high stability.Herein,a green,high stability,all-inorganic Rb_(2)CsBiCl_(6) single crystal with 0D structure was grown as a new PL material.Strikingly,using the antimony doping strategy,the broad yellow emission of Rb_(2)CsBiCl_(6) was significantly enhanced due to the enhanced absorption in the UV region,and the PL quantum yield was increased from 1%to 45%at room temperature.Furthermore,the fluorescent mechanism was revealed by the combination of optical characterizations and first-principles calculations.展开更多
Two novel tetrahedral manganese(II)complexes,(N-methylpiperidinium)MnCl_(4)(1)and(N-methylpyrrolidinium)MnCl_(4)(2),with clearly distinct fluorescence characteristics were synthesized through organic cation modulation...Two novel tetrahedral manganese(II)complexes,(N-methylpiperidinium)MnCl_(4)(1)and(N-methylpyrrolidinium)MnCl_(4)(2),with clearly distinct fluorescence characteristics were synthesized through organic cation modulation.Compound 1 exhibits prominent green luminescence with a high quantum yield of 79.37%and 2 emits unusual red emission at 611 nm.展开更多
By optimizing the Debye temperature,we identified two extremely efficient phosphors based on the S-P transition of Bi^(3+).The quantum yields of Sr_(0.99)Ga_(1.50)B_(2)O_(7):0.01Bi^(3+),0.50Al^(3+)and Ba_(0.995)Ga_(1....By optimizing the Debye temperature,we identified two extremely efficient phosphors based on the S-P transition of Bi^(3+).The quantum yields of Sr_(0.99)Ga_(1.50)B_(2)O_(7):0.01Bi^(3+),0.50Al^(3+)and Ba_(0.995)Ga_(1.60)B_(2)O_(7):0.005Bi^(3+),0.40Al^(3+)phosphors reach 96%and 99%,respectively.Moreover,Sr_(0.99)Ga_(1.50)B_(2)O_(7):0.01Bi^(3+),0.50Al^(3+)exhibits negative thermal quenching,which shows unique advantages for practical application.The blue phosphors with quantum efficiencies close to unity and superior thermal stability can be competitive candidates for practical applications.展开更多
Herein we present a structure–property relationship study of thirteen cationic iridium(III)complexes of the form of[Ir(C^N)2(P^P)]PF6 in both solution and the solid state through systematic evaluation of six bisphosp...Herein we present a structure–property relationship study of thirteen cationic iridium(III)complexes of the form of[Ir(C^N)2(P^P)]PF6 in both solution and the solid state through systematic evaluation of six bisphosphine(P^P)ligands(xantphos,dpephos,dppe,Dppe,nixantphos and isopropxantphos).展开更多
Perovskite nanoplatelets(NPLs)display excellent photoluminescence(PL)properties and unique shape features,including thickness-dependent bandgap luminescence.However,perovskite NPLs,especially those based on iodides,ex...Perovskite nanoplatelets(NPLs)display excellent photoluminescence(PL)properties and unique shape features,including thickness-dependent bandgap luminescence.However,perovskite NPLs,especially those based on iodides,exhibit poor spectral and phase stability.Herein,we propose a facile strategy to achieve a near-unity PL quantum yield(QY)and high stability of CsPbI_(3) NPLs by employing hydrogen iodate(HI)for in situ etching-assisted surface modification of the short-chain strongly bound ligand dodecylamine(DDDAm).It is found that HI can etch off the incomplete octahedron[PbI_(6)]^(4-)on the surface of CsPbI_(3) NPLs.Simultaneously,the excessive use of I^(-)ions and the introduction of DDDAm ligands effectively passivate the surface defects of NPLs,significantly improving their radiation recombination rate.As a result,the as-prepared CsPbI_(3) NPLs exhibit up to 95%PL QY,maintaining PL characteristics even after 87 days of exposure to the atmospheric environment.Conversely,untreated CsPbI_(3) NPLs display poor phase stability and transform into non-PL features(δ-CsPbI_(3))after 21 days.As a proof of concept,we fabricated perovskite LEDs(PeLEDs)using these treated CsPbI_(3) NPLs as luminescent layers for calibration.These PeLEDs showcase bright electroluminescence at 600 nm,with a full width at half maximum of 22 nm and an external quantum efficiency of 2.98%.The effective synthesis strategy using HI^(-)assisted ligand treatment presented here is expected to be extended to the synthesis of other perovskite NPLs,thereby accelerating the integration of perovskite NPLs in optoelectronic technology.展开更多
Low-dimensional lead-free Mn(Ⅱ)-based organic–inorganic metal halides(OIMHs)are promising luminescent materials,yet molecular-level fine-tuning of organic structures to achieve high quantum yield and functional red-...Low-dimensional lead-free Mn(Ⅱ)-based organic–inorganic metal halides(OIMHs)are promising luminescent materials,yet molecular-level fine-tuning of organic structures to achieve high quantum yield and functional red-light emission remains challenging.In this study,three Mn(Ⅱ)-based OIMHs were designed and synthesized using aminomethyl-pyridine isomers as cations.The results show that when 3-(aminomethyl)pyridine(3-AMPY)is employed as the organic ligand,itsπ-conjugated framework and enhanced molecular polarity facilitate the formation of a highly ordered and rigid zero-dimensional octahedral hybrid architecture,which achieves a high photoluminescence quantum yield(PLQY)of 63.42%with bright orange-red emission at 614 nm.In contrast,2-AMPY and 4-AMPY counterparts only demonstrate weak red emission with low PLQY of 14.05%and 9.23%,respectively.Notably,(4-AMPY)_(4)Mn_(3)Br_(15)exhibits sensitive and irreversible red-to-green emission switching upon thermal treatment due to phase transition.To leverage this thermoresponsive luminescence behavior,a heating-assisted digital encryption system has been developed for complex information.This work reveals how cation substitution regulates the OIMH structure–property relationship and enriches the family of lead-free metal halides for anticounterfeiting,information security,and optoelectronic applications.展开更多
Here,we report two europium(III)complexes(Eu1 and Eu2)with high photoluminescence quantum yield,based on tridentate isoquinoline derivatives(HL1 and HL2).The single crystal structures of Eu1 and Eu2 show that three li...Here,we report two europium(III)complexes(Eu1 and Eu2)with high photoluminescence quantum yield,based on tridentate isoquinoline derivatives(HL1 and HL2).The single crystal structures of Eu1 and Eu2 show that three ligands coordinate with an Eu(III)ion through diphenylphosphoryl oxygen,pyridyl nitrogen and carboxyl oxygen atoms(O^N^O)with no solvent in the first coordination sphere.展开更多
The Tibetan Plateau is characterized by lower atmospheric pressure, lower air temperature and high daily and seasonal variation due to high elevation. The photosynthesis of aaplants is significantly influenced by thes...The Tibetan Plateau is characterized by lower atmospheric pressure, lower air temperature and high daily and seasonal variation due to high elevation. The photosynthesis of aaplants is significantly influenced by these alpine environmental factors. Apparent quantum yield (αA) is one of the basic parameters of photosynthesis and mass production. Its accuracy determination is of significance to model photosynthesis of C3 plants and global change on the plateau. In the Lhasa Plateau Ecological Station with 65.4 kPa of atmospheric pressure at an elevation of 3688 m, Li-Cor 6400 portable photosynthesis system was used to measure light response curves of winter wheat in different temperatures and intercellular CO2 concentration (C,). The slope of light response curve in weak light area of PFD from 0 to 150 μmol m-2 s-1 was used to evaluate the value of αA. The dependence of αA on temperature and intercellular concentration was analyzed. In 30℃, the average value of αA was 0.0476±0.0038. It is not quite different from the values in low elevation areas. αA is influenced both by temperature and by the ratio of CO2 and O2 partial pressure ([CO2]/[O2]). The measured values in the previous study were much lower. This might be due to systematic errors from instrument and data processing methods. The values of αA decreased linearly with temperature. It decreased 0.0007 in every 1℃ increase of temperature. The decrease slope is similar to those of C3 plants in the previous researches. While [O2] is constant,αA increases with Ciwith a hyperbolic relationship. In comparison with low elevation areas, the αA on the Tibetan Plateau is more sensitive to increase of CO2.展开更多
Ionically bonded organic metal halide perovskite-like luminescent materials,which incorporate organic cations and metal halides,have emerged as a versatile multicomponent material system.However,these materials still ...Ionically bonded organic metal halide perovskite-like luminescent materials,which incorporate organic cations and metal halides,have emerged as a versatile multicomponent material system.However,these materials still face challenges in terms of low phosphorescence quantum yields and limited long persistent luminescence(LPL)colors.Herein,we present the design and synthesis of an intraligand chargetransfer organic-based metal halide perovskite-like material,in which organic cations form a compact supramolecular hydrogen-bonded organic framework(HOF)structure,exhibiting crystallization-induced phosphorescence emission of ligand,while metal halides form a unique two-dimensional(2D)structure that displays intrinsic self-trapped excitons(STE)emission under the radiation of UV light.Notably,the metal halide hybrid is found to exhibit enhanced phosphorescent photoluminescence efficiency of up to 81.05%and tunable LPL from cyan to orange compared to the pristine organic phosphor,due to the structural distortion and scaffolding effects of 2D metal halides as well as a well-packed HOF structure.Optical characterizations and theoretical calculations reveal that charge transfer from organic cations and halogen to ligand as well as STE from inorganic layers are responsible for the tunable LPL.Meanwhile,the high-efficiency phosphorescent quantum yield is attributed to stronger hydrogen bond stacking as well as structural distortion of metal halogen bands.Thus,the obtained LPL provides potentials in anti-counterfeiting,security systems,and so on.展开更多
基金supported by Medical Science and Technology Research Project of Henan Province(Joint Construction Project)(No.LHGJ20200433)National Natural Science Foundation of China(No.52122308)。
文摘White light illumination is essential in daily life,however,the substantial amount of blue light it contains can damage human eyes.Therefore,it is important to block this high-energy blue light to protect visual health.In this study,yellow-emitting carbon dots(CDs)with a quantum yield exceeding 94%were synthesized using citric acid and urea.These CDs effectively absorb blue light.By incorporating them into polystyrene,multiple films termed CDs-based blue light blocking films(CBFs)were developed,each offering different levels of blue light absorption.These CBFs exhibited excellent transparency and efficient blue light filtering capabilities.This study highlights the potential of high quantum yield CDs,which specifically absorb blue light,as foundational materials for developing light-blocking solutions against highenergy short-wavelength light.
基金supported by the National Natural Science Foundation of China (51962008)。
文摘The exploitation of a highly selective and sensitive probe to detect both cancer marker and metal ion is of great importance.In this work,the "one stone two bird" agent of 1,10-phenanthroline(phen) is designed to disrupt the polymeric lanthanide MOFs(LnMOFs,[Ln(CHO_(2))_(3)]n,Ln=Tb,la;Eu,1 b,CHO_(2)=formic acid) {[Ln(CHO_(2))_(4)·(C_(2) H_(8) N)]n,Ln=Y,2 a;Gd,2 b;Dy,2 c,C_(2)H_(8) N=dimethylamine}) into a soluble mononuclear species [Ln(phen)_(2)(NO_(3))_(3),Ln=Tb,3 a;Eu,3 b] as well as to provide an antenna for efficient photons absorption,resulting in an ultra-high luminescence quantum yield(QY,90%) europium complex.The luminescence QY is among the highest record of monomeric(zero-dimensional) lanthanide complexes.Furthermore,mononuclear Tb3+complex(3 a) functions as a multiplex sensor towards both Fe^(2+)and cancer marker of 5-hydroxyindole-3-acetic acid(5-HIAA).Importantly,the limit of detection(LOD)for sensing 5-HIAA is an ultra-sensitive value of 1 × 10 s mol/L,which is even lower than that necessary for the early diagnosis of carcinoid tumors.More interestingly,sensing results in simulated urine reveals that 3 a has potential application for early diagnosis in the clinic.
基金financially supported by the National Natural Science Foundation of China (NSFC,No.21805024)Science Foundation of China University of Petroleum (Nos. 2462019QNXZ02,2462018BJC004)+1 种基金the Scientifc and Technological Research Program of Chongqing Municipal Education Commission (No.KJ QN202001335)the Research Program ofYongchuan Science and Technology Commission (Ycstc,No.2018nb1402)。
文摘Long-emission carbon dots(CDs) is triggering immense enthusiasm on account of their intrinsic merits of high chemical stability and excellent optical properties.In this study,a facile and rapid approach was developed for the preparation of barium-doped carbon dots(Ba-CDs) with yellow fluo rescence emission and high quantum yields.Surface chemistry and the chemical architecture of the Ba-CDs was revealed under various spectroscopic methods.This work provides more insights into the effects of charge transfer caused by Ba heteroatoms,which is considered as the most challenging step in the investigation on luminescence mechanism.Remarkably,the prepared Ba-CDs were successfully applied as fluorescent probes in the detection of trace water in organic solvents(ethanol,isopropanol,acetone,tetrahydrofuran).Comparing with traditional fluorescent probes for water detection in organic solvents,Ba-CDs detection provides a more sensitive,much faster and more economical approach.
基金supported by the Program for New Century Excellent Talents in Fujian Province University。
文摘The major cytotoxic agent with most current photosensitizers used in photodynamic therapy(PDT)is widely believed to be singlet oxygen(^(1)O_(2)).Determination of the ^(1)O_(2) quantum yields for porphyrin-based photosensitizers,including hematoporphyrin derivative(HiPorfin),hematoporphyrin monomethyl ether(HMME)and photocarcinorin(PsD-007)in air-saturated dimethylformamide(DMF)solutions were performed by the direct measurement of their near-infrared luminescence.In addition,^(1)O_(2) quencher sodium azide was employed to confirm the ^(1)O_(2) generation from the investigated photosensitizers.The maximal ^(1)O_(2) luminescence occurs at about 1280 nm with full width at half maximum of 30 nm.The ^(1)O_(2) quantum yields were found to be 0.61±0.03,0.60±0.02 and 0.59±0.03 for HiPorfin,HMME and PsD-007,respectively.These results provide that these porphyrin-based photosensitizers produce ^(1)O_(2) under irradiation,which is of significance for the study of their photodynamic action in PDT.
基金Project supported by National Natural Science Foundation of China(21571162)the Guangdong Province Enterprise-University-Academy Collaborative Project(2012B091100474)
文摘A series of Tb^3+ mono-doped and Ce^3+-Tb^3+ co-doped Sr3Gd2(Si3O9)2 phosphors with high thermal stability and quantum yields were successfully prepared via the solid state reaction. The as-prepared Sr3Gd2(Si3O9)2:Tb^3+ samples showed broad excitation spectrum from 250 to 400 nm and presented characteristic emission transitions ^5D4→^7FJ(J=6, 5, 4, 3) of Tb^3+ under 313 nm excitation, which were located at about 488, 541, 584 and 620 nm. The emission intensities of Tb^3+ rose steadily in Sr3Gd2(Si3O9)2 host with the increase of Tb^3+ concentration even though Gd^3+ ions were completely replaced by Tb^3+ ions. The Ce^3+ ion as a sensitizer could efficiently improve the performance of Tb^3+ ion. First, with Ce^3+ co-doping, the excitation spectrum of Tb^3+ monitored at 541 nm showed a similar band that responds to the violet emission of Ce^3+ monitored at 416 nm. Second, the quantum yields of Sr3Gd2(Si3O9)2:Tb^3+ phosphors could be enhanced from 26.6% to 80.2% by co-doping Ce^3+. Finally, the co-doping of Ce^3+ was also effective to improve the thermal stability of Sr3Gd2(Si3O9)2:Tb^3+. As the temperature rose to 150 oC, the emission intensity of Tb^3+ remained at about 83.6% of that measured at room temperature, which was better than the commercial YAG:Ce phosphor in terms of their thermal quenching properties. These results indicated that the as-prepared Sr3Gd2(Si3O9)2:Tb^3+,Ce^3+ samples could be used as green emission phosphors for possible applications in near ultraviolet based WLEDs.
基金Supported by the National Natural Science Foundation of China(No.21501075 and 21501076)the Natural Science Foundation of Jiangsu Province(No.BK20150226)+1 种基金Open Foundation of State Key Laboratory of Structure Chemistry(20170022)Undergraduate Students Project of Jiangsu
文摘The luminescent properties of two Eu3＋ compounds based on quinoline-2-car- boxylic acid （Hqc）, [Na2Eu2（qc）6（CH3COO）2（H2O）4].2DMF （1） and [Eu2（qc）6（H2O）6].3H2O （2）, as well as their syntheses and structures are reported. Both compounds are formed by slow evaporation at room temperature and exhibit zero dimensional dinuclear structures. It is worth mentioning that a 4.5-fold enhancement in luminescent quantum yield is achieved by reducing the nonradiative deactivation, through which the quantum yield increases remarkably to 67.62% for 1 compared with 12.18% for 2.
基金supported by Japan Society for the Promotion of Science(JSPS)KAKENHI Grants(2156069624560827)
文摘Gdo.9xRxEUo.lOOH （R=Y, La） crystals were synthesized by a flux method using a mixture of NaOH and KOH as the flux. X-ray diffraction data were well refined using the Rietveld method assuming that the crystals had a monoclinic structre belonging to the P21/m space group. The unit cell volumes of the Gdo.9 xLaxEuo.OOH crystals increased with increasing x, whereas those of Gdo.9-xYxEUo.lOOH decreased with increasing x. The Commission Internationale de IEclairage （CIE） chromaticity coordinates of Gdo.9 xRxEUo.lOOH （R=Y, La） crystals were located in the red region and were nearly constant over the range ofx values considered. The fluorescence quantum yield Dr monotonically decreased with increasing x regardless of the ionic radii of the substitute ions. The fact that the Dr value of Lao.9EuoAOOH was greater than that of Gdo.gEUo.lOOH indicated that the observed decrease in the values of the Gdo.9-,LaxEuo.1OOH crystals up to x=0.3 could not be attributed to an increase in the distance between Eu3＋ ions or to a decrease in the Gd3＋ content. The decrease might be due to an increase of killer centers introduced by elemental substitutions with the larger ion.
基金financially supported by the National Natural Science Foundation of China(Nos.21174167 and 51573212)the Natural Science Foundation of Guangdong Province(Nos.S2013030013474 and 2014A030313178)
文摘The fluorescently labelled polymers including pyrene-labelled polystyrene(PyPS) and pyrene-labelled poly(methyl methacrylate)(PyPMMA) with narrow molecular weight distributions were synthesized by the atom transfer radical copolymerization(ATRCP) of styrene or methyl methacrylate with 1-pyrenemethyl methacrylate(PyMMA). The ultrathin PyPS and PyPMMA films with the thickness ranging from 30 nm to 400 nm supported on the quartz slides were prepared by spin-coating. The fluorescent quantum yield(QY) of the pyrene probe in the ultrathin polymer films was investigated by the photoluminescence spectrometer using an integrating sphere detector. The QY decreased with the reduction of film thickness in the sub-200 nm range.
文摘Theoretical dependence of the quantum yields on the size of Agnano-particle distribution from 0.8 nm to 37 nm embedded in BaOsemiconductor is discussed. The calculation results show that theincrease in Ag nano-particle diameter leads to the increase of thequantum yield threshold and the emergence of the rough Gaussian form,the results also shown that the greater increase in Ag nano-particlediameter causes the emergence of the exact Gaussian form and makesthe peaks rise up.
文摘Eu3+-doped gadolinium oxyhydroxide Gd1-xEuxOOH crystals were synthesized by the flux method. The X-ray diffraction data for the crystals were well refined assuming a monoclinic structure with the P21/m space group. Gd1-xEuxOOH (x ≤ 0.2) crystals showed strong red emission, and the highest fluorescence quantum yield (Φf) was 0.27, obtained for x = 0.10. Φf decreased rapidly as the Eu3+ content x increased above 0.2, owing to concentration quenching. Analysis with a percolation model indicated three-dimensional energy transfer between the Eu3+ ions.
基金This work was jointly supported by the Major State Basic Research Development Program of China(Grant No.2002CB412501)the National Natural Science Foundation of China(Grant Nos.30170153 and 30470280)the Key Innovation Project of Institute of Geographic Sciences and Natural Resources Research,CAS(Grant No.CXIOG-E01-03-03).
文摘The alpine meadow is widely distributed on the Tibetan Plateau with an area of about 1.2×106km2.Damxung County,located in the hinterland of the Tibetan Plateau,is the place covered with this typical vegetation.An open-path eddy covariance system was set up in Damxung rangeland station to measure the carbon flux of alpine meadow from July to October,2003.The continuous carbon flux data were used to analyze the relationship between net ecosystem carbon dioxide exchange(NEE)and photosynthetically active radiation(PAR),as well as the seasonal patterns of apparent quantum yield(α)and maximum ecosystem assimilation(Pmax).Results showed that the daytime NEE fitted fairly well with the PAR in a rectangular hyperbola function,withαdeclining in the order of peak growth period(0.0244μmolCO2·μmol-1PAR)>early growth period>seed maturing period>withering period(0.0098μmolCO2·μmol-1PAR).The Pmax did not change greatly during the first three periods,with an average of 0.433 mgCO2·m-2·s-1,i.e.9.829μmolCO2·m-2·s-1.However,during the withering period,Pmax was only 0.35 mgCO2·m-2·s-1,i.e.7.945μmolCO2·m-2·s-1.Compared with other grassland ecosystems,theαof the Tibetan Plateau alpine meadow ecosystem was much lower.
基金supported by the Natural Science Foundation of Shandong Province(ZR2020MF128,ZR2021MB059)the Key projects of Natural Science Foundation of Shandong Province(ZR2020KB014)the Key Research Program of the Chinese Academy of Sciences(ZDRW-CN-2021-3).
文摘Zero-dimensional(0D)lead-free all-inorganic metal halides have emerged as next-generation photoluminescent(PL)materials in recent years because of their extraordinary PL properties,non-toxicity,and high stability.Herein,a green,high stability,all-inorganic Rb_(2)CsBiCl_(6) single crystal with 0D structure was grown as a new PL material.Strikingly,using the antimony doping strategy,the broad yellow emission of Rb_(2)CsBiCl_(6) was significantly enhanced due to the enhanced absorption in the UV region,and the PL quantum yield was increased from 1%to 45%at room temperature.Furthermore,the fluorescent mechanism was revealed by the combination of optical characterizations and first-principles calculations.
基金supported by the National Key Research and Development Program of China(Grant 2017YFA0204800)the National Natural Science Foundation of China(21522101)the Fundamental Research Funds for the Central Universities(Grant 2242017K41027).
文摘Two novel tetrahedral manganese(II)complexes,(N-methylpiperidinium)MnCl_(4)(1)and(N-methylpyrrolidinium)MnCl_(4)(2),with clearly distinct fluorescence characteristics were synthesized through organic cation modulation.Compound 1 exhibits prominent green luminescence with a high quantum yield of 79.37%and 2 emits unusual red emission at 611 nm.
基金supported by the Key Laboratory for Green Chemical Process of Ministry of Education,Wuhan Institute of Technology,via grant GCP20190201。
文摘By optimizing the Debye temperature,we identified two extremely efficient phosphors based on the S-P transition of Bi^(3+).The quantum yields of Sr_(0.99)Ga_(1.50)B_(2)O_(7):0.01Bi^(3+),0.50Al^(3+)and Ba_(0.995)Ga_(1.60)B_(2)O_(7):0.005Bi^(3+),0.40Al^(3+)phosphors reach 96%and 99%,respectively.Moreover,Sr_(0.99)Ga_(1.50)B_(2)O_(7):0.01Bi^(3+),0.50Al^(3+)exhibits negative thermal quenching,which shows unique advantages for practical application.The blue phosphors with quantum efficiencies close to unity and superior thermal stability can be competitive candidates for practical applications.
基金the University of St Andrews for financial support.We thank Johnson Matthey and Umicore AG for the gift of materials and Cihang Yu for the preparation of isopropxantphos.We thank Dr Nail Shavaleev for the synthesis of NMS25.IDWS and AKB acknowledge support from EPSRC(EP/J01771X)We thank the EPSRC UK National Mass Spectrometry Facility at Swansea University for analytical services.This work has been supported by the Spanish Ministry of Economy and Competitiveness(MINECO)MAT2014–55200.
文摘Herein we present a structure–property relationship study of thirteen cationic iridium(III)complexes of the form of[Ir(C^N)2(P^P)]PF6 in both solution and the solid state through systematic evaluation of six bisphosphine(P^P)ligands(xantphos,dpephos,dppe,Dppe,nixantphos and isopropxantphos).
基金supported by the Outstanding Youth Fund of the Guangxi Natural Science Foundation(2022GXNSFFA035032)the National Natural Science Foundation of China(62165001,12174075)the special fund for“Guangxi Bagui Scholars”,and the“Guangxi Hundred-Talent Program”.
文摘Perovskite nanoplatelets(NPLs)display excellent photoluminescence(PL)properties and unique shape features,including thickness-dependent bandgap luminescence.However,perovskite NPLs,especially those based on iodides,exhibit poor spectral and phase stability.Herein,we propose a facile strategy to achieve a near-unity PL quantum yield(QY)and high stability of CsPbI_(3) NPLs by employing hydrogen iodate(HI)for in situ etching-assisted surface modification of the short-chain strongly bound ligand dodecylamine(DDDAm).It is found that HI can etch off the incomplete octahedron[PbI_(6)]^(4-)on the surface of CsPbI_(3) NPLs.Simultaneously,the excessive use of I^(-)ions and the introduction of DDDAm ligands effectively passivate the surface defects of NPLs,significantly improving their radiation recombination rate.As a result,the as-prepared CsPbI_(3) NPLs exhibit up to 95%PL QY,maintaining PL characteristics even after 87 days of exposure to the atmospheric environment.Conversely,untreated CsPbI_(3) NPLs display poor phase stability and transform into non-PL features(δ-CsPbI_(3))after 21 days.As a proof of concept,we fabricated perovskite LEDs(PeLEDs)using these treated CsPbI_(3) NPLs as luminescent layers for calibration.These PeLEDs showcase bright electroluminescence at 600 nm,with a full width at half maximum of 22 nm and an external quantum efficiency of 2.98%.The effective synthesis strategy using HI^(-)assisted ligand treatment presented here is expected to be extended to the synthesis of other perovskite NPLs,thereby accelerating the integration of perovskite NPLs in optoelectronic technology.
基金supported by the National Natural Science Foundation of China(No.U21A20290,22406028)the Guangdong Province General University Youth Innovative Talent Project(2024KQNCX112)+1 种基金the Projects of Talents Recruitment of GDUPT(No.2023rcyj2008)the 2022“Sail Plan”Project of the Maoming Green Chemical Industry Research Institute(No.MMGCIRI2022YFJH-Y-024).
文摘Low-dimensional lead-free Mn(Ⅱ)-based organic–inorganic metal halides(OIMHs)are promising luminescent materials,yet molecular-level fine-tuning of organic structures to achieve high quantum yield and functional red-light emission remains challenging.In this study,three Mn(Ⅱ)-based OIMHs were designed and synthesized using aminomethyl-pyridine isomers as cations.The results show that when 3-(aminomethyl)pyridine(3-AMPY)is employed as the organic ligand,itsπ-conjugated framework and enhanced molecular polarity facilitate the formation of a highly ordered and rigid zero-dimensional octahedral hybrid architecture,which achieves a high photoluminescence quantum yield(PLQY)of 63.42%with bright orange-red emission at 614 nm.In contrast,2-AMPY and 4-AMPY counterparts only demonstrate weak red emission with low PLQY of 14.05%and 9.23%,respectively.Notably,(4-AMPY)_(4)Mn_(3)Br_(15)exhibits sensitive and irreversible red-to-green emission switching upon thermal treatment due to phase transition.To leverage this thermoresponsive luminescence behavior,a heating-assisted digital encryption system has been developed for complex information.This work reveals how cation substitution regulates the OIMH structure–property relationship and enriches the family of lead-free metal halides for anticounterfeiting,information security,and optoelectronic applications.
基金supported through grants from the National Key R&D Program of China(Grant 2017YFA0205100)National Natural Science Foundation of China(Grant 21621061)+1 种基金Key Project of Science and Technology Plan of Beijing Education Commission(Grant KZ201910028038)Natural Science Foundation of Beijing Municipality(Grant 2172017).
文摘Here,we report two europium(III)complexes(Eu1 and Eu2)with high photoluminescence quantum yield,based on tridentate isoquinoline derivatives(HL1 and HL2).The single crystal structures of Eu1 and Eu2 show that three ligands coordinate with an Eu(III)ion through diphenylphosphoryl oxygen,pyridyl nitrogen and carboxyl oxygen atoms(O^N^O)with no solvent in the first coordination sphere.
基金This work was supported by the National Key Basic Research and Development Project(Grant No.2002CB41250l)the National Natural Science Foundation of China(Grant Nos.90211006,30370257 and 30470280)the Knowledge Innovation Project of Institute of Geographical Sciences and Natural Resources Research,CAS(Grant No.CXIOG-E01-03-03).
文摘The Tibetan Plateau is characterized by lower atmospheric pressure, lower air temperature and high daily and seasonal variation due to high elevation. The photosynthesis of aaplants is significantly influenced by these alpine environmental factors. Apparent quantum yield (αA) is one of the basic parameters of photosynthesis and mass production. Its accuracy determination is of significance to model photosynthesis of C3 plants and global change on the plateau. In the Lhasa Plateau Ecological Station with 65.4 kPa of atmospheric pressure at an elevation of 3688 m, Li-Cor 6400 portable photosynthesis system was used to measure light response curves of winter wheat in different temperatures and intercellular CO2 concentration (C,). The slope of light response curve in weak light area of PFD from 0 to 150 μmol m-2 s-1 was used to evaluate the value of αA. The dependence of αA on temperature and intercellular concentration was analyzed. In 30℃, the average value of αA was 0.0476±0.0038. It is not quite different from the values in low elevation areas. αA is influenced both by temperature and by the ratio of CO2 and O2 partial pressure ([CO2]/[O2]). The measured values in the previous study were much lower. This might be due to systematic errors from instrument and data processing methods. The values of αA decreased linearly with temperature. It decreased 0.0007 in every 1℃ increase of temperature. The decrease slope is similar to those of C3 plants in the previous researches. While [O2] is constant,αA increases with Ciwith a hyperbolic relationship. In comparison with low elevation areas, the αA on the Tibetan Plateau is more sensitive to increase of CO2.
基金National Natural Science Foundation of China,Grant/Award Numbers:22101162,92261114。
文摘Ionically bonded organic metal halide perovskite-like luminescent materials,which incorporate organic cations and metal halides,have emerged as a versatile multicomponent material system.However,these materials still face challenges in terms of low phosphorescence quantum yields and limited long persistent luminescence(LPL)colors.Herein,we present the design and synthesis of an intraligand chargetransfer organic-based metal halide perovskite-like material,in which organic cations form a compact supramolecular hydrogen-bonded organic framework(HOF)structure,exhibiting crystallization-induced phosphorescence emission of ligand,while metal halides form a unique two-dimensional(2D)structure that displays intrinsic self-trapped excitons(STE)emission under the radiation of UV light.Notably,the metal halide hybrid is found to exhibit enhanced phosphorescent photoluminescence efficiency of up to 81.05%and tunable LPL from cyan to orange compared to the pristine organic phosphor,due to the structural distortion and scaffolding effects of 2D metal halides as well as a well-packed HOF structure.Optical characterizations and theoretical calculations reveal that charge transfer from organic cations and halogen to ligand as well as STE from inorganic layers are responsible for the tunable LPL.Meanwhile,the high-efficiency phosphorescent quantum yield is attributed to stronger hydrogen bond stacking as well as structural distortion of metal halogen bands.Thus,the obtained LPL provides potentials in anti-counterfeiting,security systems,and so on.
