Over the past few decades,I-III-VI quantum dots(QDs)have attracted considerable attention due to their large Stokes shifts,good eco-friendliness,and wide tunable emissions.In this work,a facile microwave-assisted aque...Over the past few decades,I-III-VI quantum dots(QDs)have attracted considerable attention due to their large Stokes shifts,good eco-friendliness,and wide tunable emissions.In this work,a facile microwave-assisted aqueous route using glutathione(GSH)and citric acid(CA)as dual stabilizers is introduced to synthesize AgInGaS/ZnS(AIGS/ZnS)core/shell QDs.An exceptional photoluminescence quantum yield(PL QY)as high as 79%is successfully achieved,boosting the best performance of water-dispersible AIGS QDs.By varying the Ag/Ga ratio,the PL peak wavelength can be tuned from 547 to 616 nm,and luminescent hydrogel films with different colors are obtained by embedding AIGS/ZnS QDs in polyacrylamide/poly-vinyl alcohol(PAAm/PVA)hydrogels.The white light-emitting diode(WLED)with a high color rendering index(CRI)of 92.1(R_(9)=92.0)and a correlated color temperature(CCT)of 3022 K is fabricated using QDs-PAAm/PVA hydrogel films in combination with a blue InGaN LED chip,indicating that the as-prepared QDs are competitive color-conversion materials for WLEDs.展开更多
A new and convenient route is developed to synthesize CdSe and core-shell CdSe/CdS quantum dots（QDs） in aqueous solution.The gaseous precursors,H2Se and H2S,generated on-line by reducing SeO 3 2à with NaBH 4 an...A new and convenient route is developed to synthesize CdSe and core-shell CdSe/CdS quantum dots（QDs） in aqueous solution.The gaseous precursors,H2Se and H2S,generated on-line by reducing SeO 3 2à with NaBH 4 and the reaction between Na 2 S and diluted H2SO 4,are used to form high-quality CdSe and CdSe/CdS QDs,respectively.The synthesized water-soluble CdSe and CdSe/CdS QDs possess high quantum yield（3% and 20%） and narrow full-width-at-half-maximum（43 nm and 38 nm）.The synthesis process is easily reproducible with simple apparatus and low-toxic chemicals,and can be readily extended to the large-scale aqueous synthesis of QDs.展开更多
Lead halide perovskite nanocrystals(NCs)exhibit excellent optoelectronic performance and have drawn great interests in the fields of biological imaging and sensing.However,the poor stability of CsPbX_(3)(X=Cl,Br,I)in ...Lead halide perovskite nanocrystals(NCs)exhibit excellent optoelectronic performance and have drawn great interests in the fields of biological imaging and sensing.However,the poor stability of CsPbX_(3)(X=Cl,Br,I)in water is still a challenge to hinder their practical applications.In this work,a facile strategy has been developed for aqueous synthesis of CsPbX_(3) nanocrystals,in which L-glutamic acid(LGlu)has been used to replace oleic acid in the synthetic process.Benefiting from the synergic effects of L-Glu and oleylamine(OAm),CsPbBr_(3)nanocrystals(L-Glu/OAm-CsPbBr_(3)NCs)with high water stability have been directly prepared under a mild condition at room temperature in water,facilitated by the process of crystal phase transformation from Cs_(4)PbBr_(6) to CsPbBr_(3).L-Glu/OAm-CsPbBr_(3)NCs exhibit a high quantum yield of 85%and a narrow full width at half maximum of 16 nm,demonstrating their efficient luminescence in water.Typically,L-Glu on the surface have contributed greatly to an acidic environment and passivation of surface defects,improving the water stability and dispersibility of CsPbBr_(3)nanocrystals.Moreover,L-Glu/OAm-CsPbBr_(3)NCs exhibit great biocompatibility due to the presence of L-Glu,resulting in their good performance for HeLa cell imaging.Thus,we propose a facile and effective method to prepare CsPbBr_(3)nanocrystals with excellent water stability by using L-Glu and OAm as cooperated ligands and expand their application in cell imaging.展开更多
Aqueous synthesis is a green but challenging pathway to produce cadmium-free,bright,and near-infrared(NIR)emitting quantum dots(QDs).Herein,we develop a straightforward aqueous phase approach to prepare Zn-Cu-In-Se QD...Aqueous synthesis is a green but challenging pathway to produce cadmium-free,bright,and near-infrared(NIR)emitting quantum dots(QDs).Herein,we develop a straightforward aqueous phase approach to prepare Zn-Cu-In-Se QDs with tunable emission from 630 to 800 nm through varying the molar ratio of Zn and Cu.The ultrasmall nanoparticle size remains nearly fixed(~2.6 nm)when the QD composition is varied,allowing for the effects of composition on the optical properties of QDs to be decoupled from the impact of particle size.By leveraging the off-stoichiometric effect on photoluminescence(PL),Zn-Cu-In-Se QDs with a Zn:Cu molar ratio of 1.0 show a long PL decay lifetime of 211 ns and an absolute photoluminescence quantum yield(PLQY)of 14.2%.The PLQY is further enhanced by overcoating a ZnS shell,reaching up to 25.8%.Based on the bright,biocompatible,and emission-tunable QDs,nanoprobes with targeting capability for multiple tumor markers are further constructed and employed to simultaneously ascertain targets in the cytoplasm and cell membrane.This study provides a green and effective strategy for achieving bright and biocompatible NIR quantum dots for multiplexed biodetection applications.展开更多
Carbon supported Pt-Co alloys are among the most promising electrocatalysts towards oxygen reduction reaction(ORR)for the application in low temperature fuel cells and beyond,thus their facile and green synthesis is h...Carbon supported Pt-Co alloys are among the most promising electrocatalysts towards oxygen reduction reaction(ORR)for the application in low temperature fuel cells and beyond,thus their facile and green synthesis is highly demanded.Herein we initially report an alternate aqueous phase one-pot synthesis of such catalysts(containing nominally ca.20 wt.%Pt)based on dimethylamine borane(DMAB)reduction.The as-obtained electrocatalyst(denoted as Pt3Co/C-DMAB)is compared with the ones obtained by NaBH4 and N2H4·H2O reduction(denoted as Pt3Co/C-NaBH4 and Pt3Co/C-N2H4·H2O,respectively)as well as a commercial Pt/C,in terms of the structure and electrocatalytic property.It turns out that Pt3Co/C-DMAB exhibits the highest ORR performance among all the tested samples in an O2-saturated 0.1 mol/L HClO4,with the mass activity(specific activity)ca.4(6)times as large as that for Pt/C.After 10000 cycles of the accelerated degradation test,the half-wave potential for ORR on Pt3Co/C-DMAB decreases only by 4 mV,in contrast to 24 mV for that on Pt/C.Pt3Co/C-NaBH4 or Pt3Co/C-N2H4·H2O shows a specific activity comparable to that for Pt3Co/C-DMAB,but a mass activity similar to that for Pt/C.ICP-AES,TEM,XRD and XPS characterizations indicate that Pt3Co nanoparticles are well-dispersed and alloyed with a mean particle size of ca.3.4±0.4 nm,contributing to the prominent electrocatalytic performance of Pt3Co/C-DMAB.This simple aqueous synthetic route may provide an alternate opportunity for developing efficient practical electrocatalysts for ORR.展开更多
Nine complexes(RC_5H_4)_2Ti(O_2CC_6H_4X)_2(R=H,CH_3;X=H,o-Cl,o-OH, o-NH_2,o-NHPh)have been conveniently prepared by the reaction of (RC_5H_4)_2TiCl_2 with 2 equiv.sodium salts of corresponding carboxylic acid in aqueo...Nine complexes(RC_5H_4)_2Ti(O_2CC_6H_4X)_2(R=H,CH_3;X=H,o-Cl,o-OH, o-NH_2,o-NHPh)have been conveniently prepared by the reaction of (RC_5H_4)_2TiCl_2 with 2 equiv.sodium salts of corresponding carboxylic acid in aqueous solution containing acetylacetone.The carboxylate ligands in the complexes coordinate to titanium atom in monodentate mode.展开更多
We report a facile aqueous phase synthesis for prepar-ing water-soluble inverted core/shell ZnSe/CdSe semiconductor nanocrystals.The samples were characterized by X-ray diffraction(XRD),transmission electron microscop...We report a facile aqueous phase synthesis for prepar-ing water-soluble inverted core/shell ZnSe/CdSe semiconductor nanocrystals.The samples were characterized by X-ray diffraction(XRD),transmission electron microscopy(TEM),and their optical properties were investigated by using UV-vis-NIR spectropho-tometer and fluorescence spectrophotometer.The results indicate that the synthesized ZnSe/CdSe nanocrystals are inverted core/shell structure with diameter of about 5 nm.Furthermore,their absorption band-edge is red-shifted with the growth of CdSe shell;correspondingly,their emission wavelength can be tuned from 460 nm to 604 nm.展开更多
This work mainly investigated the influences of some factors, such as, synthesis methods, precursor alteraatives, and vacuum heat-treating process, etc, on the fluorescent characteristics of the semiconductor quantum ...This work mainly investigated the influences of some factors, such as, synthesis methods, precursor alteraatives, and vacuum heat-treating process, etc, on the fluorescent characteristics of the semiconductor quantum dots synthesized by aqueous phase. The research results indicate that the fluorescent characteristic of water- solution sample prepared from Na2 SO3 precursor was sensitive to water bath heating time, and specially, its photohuninescence spectrum shows the unique phenomenon of double excitation and emission peaks. Meanwhile, the fluorescent characteristic of water- solution sample prepared from NaBH4 precursor is slightly influenced by water bath heating time, and the sugface of CdSe quantum dots could be passivated by the excessive amount of NaBH4 precursor, which results in the effective decrease of surface traps and great enhancement of quantum yield. Furthermore, the fluorescent emission peaks of samples could be sharpened by vacuum heat-treating process, with its spectral full width at half of maximum （FWHM） around 30- 40 run, so the emission peaks become redshifi, of which the intensity greatly increases.展开更多
This paper explored the feasibility for the application of luminescent CdTe quantum dots prepared in aqueous phase to live cell imaging. The highly luminescent CdTe quantum dots （QDs） were first prepared in aqueous ...This paper explored the feasibility for the application of luminescent CdTe quantum dots prepared in aqueous phase to live cell imaging. The highly luminescent CdTe quantum dots （QDs） were first prepared in aqueous phase, and then were covalentiy coupled to a plant lectin （UEA-1）, as a fluorescent probe. After incubating with of human umbilical vein endothelial cells （HUVECs）, the QD probe with UEA-1 was able to specifically bind the corresponding cell receptor. The good cell images were obtained in live cells using laser confocal scanning microscopy. We predict that QDs prepared in water phase will probably become an attractive alternative probe in cellular imaging and bio-labeling.展开更多
A convenient,effcient and environmentally benign procedure has been developed for the synthesis of pyrano[4,3-b]pyran derivatives via a one-pot,three-component reaction of 4-hydroxy-6-methylpyran-2-one,aldehydes and m...A convenient,effcient and environmentally benign procedure has been developed for the synthesis of pyrano[4,3-b]pyran derivatives via a one-pot,three-component reaction of 4-hydroxy-6-methylpyran-2-one,aldehydes and malononitrile in water using H6P2W18O62á18H2O as catalyst.Reusability of the catalyst and reaction media,short reaction times and easy isolation of products are some added advantages of the present methodology.展开更多
The synthesis of CdSe/ZnS core/shell nanocrystals though aqueous phase using the coprecipitation method was reported. The influences of factors such as injection methods and dosages of precursors, reaction duration of...The synthesis of CdSe/ZnS core/shell nanocrystals though aqueous phase using the coprecipitation method was reported. The influences of factors such as injection methods and dosages of precursors, reaction duration of water-bathing and the initial CdSe：ZnS molar ratio were discussed. In comparison to the CdSe plain core nanocrystals, the CdSe/ZnS core/shell nanocrystals show much brighter photoluminescence demonstrated by the photoluminescence spectra. The epitaxial growth of the core/shell structures was verified by TEM and XRD.展开更多
Bismuth-based fluoride nanocrystalline materials are an emerging class of host matrixes for luminescent ions with promising applications in optoelectronic devices and medical diagnosis.However,rapid aqueous-phase synt...Bismuth-based fluoride nanocrystalline materials are an emerging class of host matrixes for luminescent ions with promising applications in optoelectronic devices and medical diagnosis.However,rapid aqueous-phase synthesis of highly stable bismuth-based fluoride nanocrystals at low temperature(room temperature∼90℃)is still a significant challenge.Herein we report an ultrafast(1 min only)and economical aqueous method to synthesize lanthanide-doped K_(0.3)Bi_(0.7)F_(2.4)upconversion nanocrystalline particles at low temperature.The resultant materials show exceptional upconversion luminescence performance under the excitation of a 980 nm near-infrared laser.More importantly,these fluoride nanocrystalline particles show excellent stability against high temperature up to 200℃,high excitation power density(80 W cm^(−2))and prolonged water soaking(60 days or more).The proposed simple synthesis route,rare-earth free fluoride matrix,commendable upconversion luminescence performance and excellent chemical and thermal stability opens the door to access these lanthanide-doped K0.3Bi0.7F2.4 upconversion nanocrystalline particles for anti-counterfeiting and other daily applications.展开更多
Herein,we proposed a green synthetic route based on coordination chemistry to produce nanostructured layered double hydroxides(LDHs).The synthesized NiAl-,NiFe-and ZnAl-LDHs exhibited similar morphologies and crystal ...Herein,we proposed a green synthetic route based on coordination chemistry to produce nanostructured layered double hydroxides(LDHs).The synthesized NiAl-,NiFe-and ZnAl-LDHs exhibited similar morphologies and crystal structures.A possible mechanism for LDH formation was proposed based on pHpotentiometric titrations.Extensive electronic spectroscopy analyses,interpreted through the lens of ligand field theory,provided key insights into the formation mechanism of NiFe-LDH.展开更多
New Ce(Ⅳ)metal-organic frameworks(MOFs)are reported based on the aliphatic linker butane-1,2,3,4-tetracarboxylic acid(H4BTCA).These materials were prepared using an eco-friendly aqueous-based synthesis,and their stru...New Ce(Ⅳ)metal-organic frameworks(MOFs)are reported based on the aliphatic linker butane-1,2,3,4-tetracarboxylic acid(H4BTCA).These materials were prepared using an eco-friendly aqueous-based synthesis,and their structures were elucidated through microcrystal electron diffraction(MicroED)and powder X-ray diffraction(PXRD).They feature an 8-coordinated net with a bcu topology,rarely observed for Ce(Ⅳ)MOFs.Interconversion between the MOFs was easily achieved via treatment with basic or formic acid solutions,revealing the breathing of the MOFs’frameworks.The MOFs were investigated for their ability to sorb Pb^(2+)under both batch and continuous flow conditions.The results showed relatively high Pb^(2+)sorption capacities(up to 254 mg Pb per g)and an exceptional capability for the rapid removal(in less than 10 min of MOF-solution contact)of Pb^(2+)from low initial concentrations of complex solutions and real-world water samples.Notably,the materials in the form of calcium alginate-based beads used as a stationary phase in a column(along with sea sand)demonstrate a remarkable ability to capture Pb^(2+)under continuous flow,showing decent removal capacities,excellent regeneration efficiency,and reusability.The mechanism of the Pb^(2+)sorption process was determined via experimental data,indicating strong interactions of the MOF’s functional groups(carboxylate and hydroxide groups)with the Pb^(2+)ions.展开更多
The highly regio-and stereoselective hydroborations of unactivated internal alkynes with diboron compound catalyzed by Cu（OTf）2 with spiro（phosphoamidite） as ligand in the presence of Cs2CO3 in water was developed...The highly regio-and stereoselective hydroborations of unactivated internal alkynes with diboron compound catalyzed by Cu（OTf）2 with spiro（phosphoamidite） as ligand in the presence of Cs2CO3 in water was developed.This protocol was applied efficiently in the aqueous synthesis of multi-substituted vinylboranes.展开更多
Herein,we have developed a method for the facile aqueous synthesis of ligand-free cesium lead halide perovskite nanoplatelets with pure CsPb_(2)Br_(5).The ligand-free CsPb_(2)Br_(5)nanoplatelets showed good environmen...Herein,we have developed a method for the facile aqueous synthesis of ligand-free cesium lead halide perovskite nanoplatelets with pure CsPb_(2)Br_(5).The ligand-free CsPb_(2)Br_(5)nanoplatelets showed good environmental stability with green and easy synthesis.In addition to their demonstrated good stability in aqueous solutions,and enhanced charge separation and charge transportability.展开更多
基金supported by the National Natural Science Foundation of China(NSFC,No.62074044,NSFC,No.61904036),Zhongshan-Fudan Joint Innovation Center,Jihua Laboratory Projects of Guangdong Province(X190111UZ190)Shanghai Post-doctoral Excellence Program(2021016)Shanghai Rising-Star program(22YF1402000).
文摘Over the past few decades,I-III-VI quantum dots(QDs)have attracted considerable attention due to their large Stokes shifts,good eco-friendliness,and wide tunable emissions.In this work,a facile microwave-assisted aqueous route using glutathione(GSH)and citric acid(CA)as dual stabilizers is introduced to synthesize AgInGaS/ZnS(AIGS/ZnS)core/shell QDs.An exceptional photoluminescence quantum yield(PL QY)as high as 79%is successfully achieved,boosting the best performance of water-dispersible AIGS QDs.By varying the Ag/Ga ratio,the PL peak wavelength can be tuned from 547 to 616 nm,and luminescent hydrogel films with different colors are obtained by embedding AIGS/ZnS QDs in polyacrylamide/poly-vinyl alcohol(PAAm/PVA)hydrogels.The white light-emitting diode(WLED)with a high color rendering index(CRI)of 92.1(R_(9)=92.0)and a correlated color temperature(CCT)of 3022 K is fabricated using QDs-PAAm/PVA hydrogel films in combination with a blue InGaN LED chip,indicating that the as-prepared QDs are competitive color-conversion materials for WLEDs.
文摘A new and convenient route is developed to synthesize CdSe and core-shell CdSe/CdS quantum dots（QDs） in aqueous solution.The gaseous precursors,H2Se and H2S,generated on-line by reducing SeO 3 2à with NaBH 4 and the reaction between Na 2 S and diluted H2SO 4,are used to form high-quality CdSe and CdSe/CdS QDs,respectively.The synthesized water-soluble CdSe and CdSe/CdS QDs possess high quantum yield（3% and 20%） and narrow full-width-at-half-maximum（43 nm and 38 nm）.The synthesis process is easily reproducible with simple apparatus and low-toxic chemicals,and can be readily extended to the large-scale aqueous synthesis of QDs.
基金support from the National Natural Science Foundation of China(Nos.22221001,and 22131007)the Science and Technology Major Plan of Gansu Province(No.23ZDGA012)the 111 project(No.B20027).
文摘Lead halide perovskite nanocrystals(NCs)exhibit excellent optoelectronic performance and have drawn great interests in the fields of biological imaging and sensing.However,the poor stability of CsPbX_(3)(X=Cl,Br,I)in water is still a challenge to hinder their practical applications.In this work,a facile strategy has been developed for aqueous synthesis of CsPbX_(3) nanocrystals,in which L-glutamic acid(LGlu)has been used to replace oleic acid in the synthetic process.Benefiting from the synergic effects of L-Glu and oleylamine(OAm),CsPbBr_(3)nanocrystals(L-Glu/OAm-CsPbBr_(3)NCs)with high water stability have been directly prepared under a mild condition at room temperature in water,facilitated by the process of crystal phase transformation from Cs_(4)PbBr_(6) to CsPbBr_(3).L-Glu/OAm-CsPbBr_(3)NCs exhibit a high quantum yield of 85%and a narrow full width at half maximum of 16 nm,demonstrating their efficient luminescence in water.Typically,L-Glu on the surface have contributed greatly to an acidic environment and passivation of surface defects,improving the water stability and dispersibility of CsPbBr_(3)nanocrystals.Moreover,L-Glu/OAm-CsPbBr_(3)NCs exhibit great biocompatibility due to the presence of L-Glu,resulting in their good performance for HeLa cell imaging.Thus,we propose a facile and effective method to prepare CsPbBr_(3)nanocrystals with excellent water stability by using L-Glu and OAm as cooperated ligands and expand their application in cell imaging.
基金the National Key Research and Development Program of China(No.2018YFA0208800)the National Natural Science Foundation of China(NSFC)(Nos.22177115,81671755,and 21802083)+2 种基金the Youth Innovation Promotion Association CAS(No.2018042)the Taishan Scholar Program of Shandong Province of China(No.ts20110829)Cancer Prevention&Research Institute of Texas(No.RR190056).
文摘Aqueous synthesis is a green but challenging pathway to produce cadmium-free,bright,and near-infrared(NIR)emitting quantum dots(QDs).Herein,we develop a straightforward aqueous phase approach to prepare Zn-Cu-In-Se QDs with tunable emission from 630 to 800 nm through varying the molar ratio of Zn and Cu.The ultrasmall nanoparticle size remains nearly fixed(~2.6 nm)when the QD composition is varied,allowing for the effects of composition on the optical properties of QDs to be decoupled from the impact of particle size.By leveraging the off-stoichiometric effect on photoluminescence(PL),Zn-Cu-In-Se QDs with a Zn:Cu molar ratio of 1.0 show a long PL decay lifetime of 211 ns and an absolute photoluminescence quantum yield(PLQY)of 14.2%.The PLQY is further enhanced by overcoating a ZnS shell,reaching up to 25.8%.Based on the bright,biocompatible,and emission-tunable QDs,nanoprobes with targeting capability for multiple tumor markers are further constructed and employed to simultaneously ascertain targets in the cytoplasm and cell membrane.This study provides a green and effective strategy for achieving bright and biocompatible NIR quantum dots for multiplexed biodetection applications.
基金supported by the National Basic Research Program of China(973 Program,2015CB932303)the National Natural Science Foundation of China(NSFC)(21733004 and 21473039)the International Cooperation Program of Shanghai Science and Technology Committee(STCSM)(17520711200)~~
文摘Carbon supported Pt-Co alloys are among the most promising electrocatalysts towards oxygen reduction reaction(ORR)for the application in low temperature fuel cells and beyond,thus their facile and green synthesis is highly demanded.Herein we initially report an alternate aqueous phase one-pot synthesis of such catalysts(containing nominally ca.20 wt.%Pt)based on dimethylamine borane(DMAB)reduction.The as-obtained electrocatalyst(denoted as Pt3Co/C-DMAB)is compared with the ones obtained by NaBH4 and N2H4·H2O reduction(denoted as Pt3Co/C-NaBH4 and Pt3Co/C-N2H4·H2O,respectively)as well as a commercial Pt/C,in terms of the structure and electrocatalytic property.It turns out that Pt3Co/C-DMAB exhibits the highest ORR performance among all the tested samples in an O2-saturated 0.1 mol/L HClO4,with the mass activity(specific activity)ca.4(6)times as large as that for Pt/C.After 10000 cycles of the accelerated degradation test,the half-wave potential for ORR on Pt3Co/C-DMAB decreases only by 4 mV,in contrast to 24 mV for that on Pt/C.Pt3Co/C-NaBH4 or Pt3Co/C-N2H4·H2O shows a specific activity comparable to that for Pt3Co/C-DMAB,but a mass activity similar to that for Pt/C.ICP-AES,TEM,XRD and XPS characterizations indicate that Pt3Co nanoparticles are well-dispersed and alloyed with a mean particle size of ca.3.4±0.4 nm,contributing to the prominent electrocatalytic performance of Pt3Co/C-DMAB.This simple aqueous synthetic route may provide an alternate opportunity for developing efficient practical electrocatalysts for ORR.
文摘Nine complexes(RC_5H_4)_2Ti(O_2CC_6H_4X)_2(R=H,CH_3;X=H,o-Cl,o-OH, o-NH_2,o-NHPh)have been conveniently prepared by the reaction of (RC_5H_4)_2TiCl_2 with 2 equiv.sodium salts of corresponding carboxylic acid in aqueous solution containing acetylacetone.The carboxylate ligands in the complexes coordinate to titanium atom in monodentate mode.
基金Supported by the National Natural Science Foundation of China(10874134)the Specialized Research Fund for the Doctoral Program of Higher Education of China(20060486031)
文摘We report a facile aqueous phase synthesis for prepar-ing water-soluble inverted core/shell ZnSe/CdSe semiconductor nanocrystals.The samples were characterized by X-ray diffraction(XRD),transmission electron microscopy(TEM),and their optical properties were investigated by using UV-vis-NIR spectropho-tometer and fluorescence spectrophotometer.The results indicate that the synthesized ZnSe/CdSe nanocrystals are inverted core/shell structure with diameter of about 5 nm.Furthermore,their absorption band-edge is red-shifted with the growth of CdSe shell;correspondingly,their emission wavelength can be tuned from 460 nm to 604 nm.
文摘This work mainly investigated the influences of some factors, such as, synthesis methods, precursor alteraatives, and vacuum heat-treating process, etc, on the fluorescent characteristics of the semiconductor quantum dots synthesized by aqueous phase. The research results indicate that the fluorescent characteristic of water- solution sample prepared from Na2 SO3 precursor was sensitive to water bath heating time, and specially, its photohuninescence spectrum shows the unique phenomenon of double excitation and emission peaks. Meanwhile, the fluorescent characteristic of water- solution sample prepared from NaBH4 precursor is slightly influenced by water bath heating time, and the sugface of CdSe quantum dots could be passivated by the excessive amount of NaBH4 precursor, which results in the effective decrease of surface traps and great enhancement of quantum yield. Furthermore, the fluorescent emission peaks of samples could be sharpened by vacuum heat-treating process, with its spectral full width at half of maximum （FWHM） around 30- 40 run, so the emission peaks become redshifi, of which the intensity greatly increases.
基金This work was financially supported by the National Natural Science Foundation of China （No. 20335020, 90408014） and the Nano-Science Foundation of Shanghai （0452NM052, 05NM0500 -2）.
文摘This paper explored the feasibility for the application of luminescent CdTe quantum dots prepared in aqueous phase to live cell imaging. The highly luminescent CdTe quantum dots （QDs） were first prepared in aqueous phase, and then were covalentiy coupled to a plant lectin （UEA-1）, as a fluorescent probe. After incubating with of human umbilical vein endothelial cells （HUVECs）, the QD probe with UEA-1 was able to specifically bind the corresponding cell receptor. The good cell images were obtained in live cells using laser confocal scanning microscopy. We predict that QDs prepared in water phase will probably become an attractive alternative probe in cellular imaging and bio-labeling.
文摘A convenient,effcient and environmentally benign procedure has been developed for the synthesis of pyrano[4,3-b]pyran derivatives via a one-pot,three-component reaction of 4-hydroxy-6-methylpyran-2-one,aldehydes and malononitrile in water using H6P2W18O62á18H2O as catalyst.Reusability of the catalyst and reaction media,short reaction times and easy isolation of products are some added advantages of the present methodology.
基金the National Natural Science Foundation of China (No. 50572072)Nano Special Fouds from Science and Technology Commission of Shanghai Municipality (No. 0852nm05200)
文摘The synthesis of CdSe/ZnS core/shell nanocrystals though aqueous phase using the coprecipitation method was reported. The influences of factors such as injection methods and dosages of precursors, reaction duration of water-bathing and the initial CdSe：ZnS molar ratio were discussed. In comparison to the CdSe plain core nanocrystals, the CdSe/ZnS core/shell nanocrystals show much brighter photoluminescence demonstrated by the photoluminescence spectra. The epitaxial growth of the core/shell structures was verified by TEM and XRD.
基金support from the National Natural Science Foundation of China(grant no.51902184)the Shandong Provincial Natural Science Foundation(grant no.ZR2019BEM028)+2 种基金the“Qi-Lu Young Scholar Fund”(grant no.31370088963167)from Shandong Universitysupport from the Major Basic Research Projects of Shandong Natural Science Foundation(ZR2018ZB0104)supported by the National Natural Science Foundation of China(grant no.21805111)and the Taishan Scholar Fund.
文摘Bismuth-based fluoride nanocrystalline materials are an emerging class of host matrixes for luminescent ions with promising applications in optoelectronic devices and medical diagnosis.However,rapid aqueous-phase synthesis of highly stable bismuth-based fluoride nanocrystals at low temperature(room temperature∼90℃)is still a significant challenge.Herein we report an ultrafast(1 min only)and economical aqueous method to synthesize lanthanide-doped K_(0.3)Bi_(0.7)F_(2.4)upconversion nanocrystalline particles at low temperature.The resultant materials show exceptional upconversion luminescence performance under the excitation of a 980 nm near-infrared laser.More importantly,these fluoride nanocrystalline particles show excellent stability against high temperature up to 200℃,high excitation power density(80 W cm^(−2))and prolonged water soaking(60 days or more).The proposed simple synthesis route,rare-earth free fluoride matrix,commendable upconversion luminescence performance and excellent chemical and thermal stability opens the door to access these lanthanide-doped K0.3Bi0.7F2.4 upconversion nanocrystalline particles for anti-counterfeiting and other daily applications.
基金the Italian Ministry of University and Research for funding through the LEGACY(healing wide-gap chalcopyrite,grant no.20223ZP4WP)project of national relevance(PRIN 2022),under the ERC PE3 Condensed Matter Physics sector。
文摘Herein,we proposed a green synthetic route based on coordination chemistry to produce nanostructured layered double hydroxides(LDHs).The synthesized NiAl-,NiFe-and ZnAl-LDHs exhibited similar morphologies and crystal structures.A possible mechanism for LDH formation was proposed based on pHpotentiometric titrations.Extensive electronic spectroscopy analyses,interpreted through the lens of ligand field theory,provided key insights into the formation mechanism of NiFe-LDH.
基金the European Union NextGenerationEU under the call RESEARCH-CREATE-INNOVATE 16971 Recovery and Resilience Facility(project code:TAEDK-06193).
文摘New Ce(Ⅳ)metal-organic frameworks(MOFs)are reported based on the aliphatic linker butane-1,2,3,4-tetracarboxylic acid(H4BTCA).These materials were prepared using an eco-friendly aqueous-based synthesis,and their structures were elucidated through microcrystal electron diffraction(MicroED)and powder X-ray diffraction(PXRD).They feature an 8-coordinated net with a bcu topology,rarely observed for Ce(Ⅳ)MOFs.Interconversion between the MOFs was easily achieved via treatment with basic or formic acid solutions,revealing the breathing of the MOFs’frameworks.The MOFs were investigated for their ability to sorb Pb^(2+)under both batch and continuous flow conditions.The results showed relatively high Pb^(2+)sorption capacities(up to 254 mg Pb per g)and an exceptional capability for the rapid removal(in less than 10 min of MOF-solution contact)of Pb^(2+)from low initial concentrations of complex solutions and real-world water samples.Notably,the materials in the form of calcium alginate-based beads used as a stationary phase in a column(along with sea sand)demonstrate a remarkable ability to capture Pb^(2+)under continuous flow,showing decent removal capacities,excellent regeneration efficiency,and reusability.The mechanism of the Pb^(2+)sorption process was determined via experimental data,indicating strong interactions of the MOF’s functional groups(carboxylate and hydroxide groups)with the Pb^(2+)ions.
文摘The highly regio-and stereoselective hydroborations of unactivated internal alkynes with diboron compound catalyzed by Cu（OTf）2 with spiro（phosphoamidite） as ligand in the presence of Cs2CO3 in water was developed.This protocol was applied efficiently in the aqueous synthesis of multi-substituted vinylboranes.
基金supported by the National Natural Science Foundation of China(21874020)the Key Project of Natural Science Foundation of Fujian Province(2020J02038)+2 种基金the National Science Foundation for Distinguished Young Scholars of Fujian Province(2020J06019)Program for Fujian Youth Talent Support Project(2019B016)Program for Fujian Top-Notch Innovative Personnel(Fujian Commission Talent[2018]No.5).
文摘Herein,we have developed a method for the facile aqueous synthesis of ligand-free cesium lead halide perovskite nanoplatelets with pure CsPb_(2)Br_(5).The ligand-free CsPb_(2)Br_(5)nanoplatelets showed good environmental stability with green and easy synthesis.In addition to their demonstrated good stability in aqueous solutions,and enhanced charge separation and charge transportability.
基金financially supported by the National Key Research and Development Program of China(2022YFB3803300)the Natural Science Foundation of Hunan Province of China(2021JJ10058)the Major Scientific and Technological Project of Changsha in 2022(kq2301002)。
