Poly(organophosphazenes) have potential applications in making water-soluble and biocompatible quantum dots (QDs) due to their wide variety of properties. The CdSe QDs of green emission and the core-shell CdSe/ZnS QDs...Poly(organophosphazenes) have potential applications in making water-soluble and biocompatible quantum dots (QDs) due to their wide variety of properties. The CdSe QDs of green emission and the core-shell CdSe/ZnS QDs of red emission were prepared. Subsequently the trioctylphosphine oxide-stabilized CdSe/ZnS QDs were transferred from chloroform into water through a ligand exchange process with poly(glycino amino acid)phosphazenes, which can be obtained from the saponification of poly (glycino amino ester)phosphazenes at room temperature. The resulting QDs-polymer nanocomposite particles can form colloidally stable suspensions in water and exhibit good photostability.展开更多
A series of boron- and phosphorus-doped silicon wafers are used to prepare a series of doped silicon nanocrystals （nc-Si） by high-energy ball milling with carboxylic acid-terminated surface. The sizes of the nc-Si s...A series of boron- and phosphorus-doped silicon wafers are used to prepare a series of doped silicon nanocrystals （nc-Si） by high-energy ball milling with carboxylic acid-terminated surface. The sizes of the nc-Si samples are demonstrated to be 〈 S nm. The doping levels of the nc-Si are found to be nonlinearly dependent on the original doping level of the wafers by x-ray photoelectron spectroscopy measurement. It is found that the nonlinear doping process will lead to the nonlinear chemical passivation and photoluminescence （I3L） intensity evolution. The doping, chemical passivation and PL mechanisms of the doped nc-Si samples prepared by mechanochemical synthesis are analyzed in detail.展开更多
The impact of alkali metal carboxylates on the synthesis of colloidal quantum dots(CQDs)was investigated.Through a ligand removal experiment,we demonstrated that due to its high hydrophilic nature,sodium oleate disper...The impact of alkali metal carboxylates on the synthesis of colloidal quantum dots(CQDs)was investigated.Through a ligand removal experiment,we demonstrated that due to its high hydrophilic nature,sodium oleate dispersed in n-octadecene(ODE)with the formation of micelles with the help of other polar molecules,which resulted in reduced concentration of oleic acid and cadmium oleate both in the solution and on the surface of CQDs.These effects allow for control the size of CdSe CQDs in a wide range when synthesizing them by solely changing the amount of sodium oleate,under either cation-rich or anion-rich conditions.Additionally,enhanced ligand dynamics promote morphology transformation and suppress size deviation caused by different morphologies'existence in CQDs synthesis.Alkali metal oleate not only stabilized anion-rich CdSe CQDs but also results in highly crystallized wurtzite structure of CdSe CQDs when synthesizing them with excess anions.Furthermore,under anion-rich synthetic condition,anisotropic growth can be realized,leading to nanorods and nanoplatelets based on the alkali metal ions used.Given their outstanding effects and widely applicable synthetic conditions,alkali metal carboxylates offer new possibilities for designing efficient methods for synthesizing CQDs.展开更多
This study aims at preparing water soluble aspartic acid （ASP） modified CdTe quantum dots with tunable fluorescence emission controlled by reaction time. The size of the synthesized CdTe quantum dots was evaluated u...This study aims at preparing water soluble aspartic acid （ASP） modified CdTe quantum dots with tunable fluorescence emission controlled by reaction time. The size of the synthesized CdTe quantum dots was evaluated using transmission electron microscope （TEM） and also calculated based on their UV-vis spectra. The optical properties of TGA-CdTe quantum dots were characterized by UV-vis and fluorescence （FL） spectroscopy. The red-shift in the UV-vis absorption and FL emission with the increase of reaction time was observed. The biocompatibility examination indicated that the ASP modified CdTe QDs had low cytotoxicity.展开更多
基金Project(2006CB601005) supported by the National Basic Research Program of Chinaproject(200331) supported by the National Excellent Doctoral Dissertations of Chinaproject(Q5009001200801) supported by the Post-Doctoral Science and Technology Foundation from Beijing University of Technology
文摘Poly(organophosphazenes) have potential applications in making water-soluble and biocompatible quantum dots (QDs) due to their wide variety of properties. The CdSe QDs of green emission and the core-shell CdSe/ZnS QDs of red emission were prepared. Subsequently the trioctylphosphine oxide-stabilized CdSe/ZnS QDs were transferred from chloroform into water through a ligand exchange process with poly(glycino amino acid)phosphazenes, which can be obtained from the saponification of poly (glycino amino ester)phosphazenes at room temperature. The resulting QDs-polymer nanocomposite particles can form colloidally stable suspensions in water and exhibit good photostability.
基金Supported by the National Natural Science Foundation of China under Grant No 61575216
文摘A series of boron- and phosphorus-doped silicon wafers are used to prepare a series of doped silicon nanocrystals （nc-Si） by high-energy ball milling with carboxylic acid-terminated surface. The sizes of the nc-Si samples are demonstrated to be 〈 S nm. The doping levels of the nc-Si are found to be nonlinearly dependent on the original doping level of the wafers by x-ray photoelectron spectroscopy measurement. It is found that the nonlinear doping process will lead to the nonlinear chemical passivation and photoluminescence （I3L） intensity evolution. The doping, chemical passivation and PL mechanisms of the doped nc-Si samples prepared by mechanochemical synthesis are analyzed in detail.
基金supported by the Shanghai Rising-Star Program(No.22QA1406300)the National Natural Science Foundation of China(No.U22A2072)the Start-up Funding of ShanghaiTech University.
文摘The impact of alkali metal carboxylates on the synthesis of colloidal quantum dots(CQDs)was investigated.Through a ligand removal experiment,we demonstrated that due to its high hydrophilic nature,sodium oleate dispersed in n-octadecene(ODE)with the formation of micelles with the help of other polar molecules,which resulted in reduced concentration of oleic acid and cadmium oleate both in the solution and on the surface of CQDs.These effects allow for control the size of CdSe CQDs in a wide range when synthesizing them by solely changing the amount of sodium oleate,under either cation-rich or anion-rich conditions.Additionally,enhanced ligand dynamics promote morphology transformation and suppress size deviation caused by different morphologies'existence in CQDs synthesis.Alkali metal oleate not only stabilized anion-rich CdSe CQDs but also results in highly crystallized wurtzite structure of CdSe CQDs when synthesizing them with excess anions.Furthermore,under anion-rich synthetic condition,anisotropic growth can be realized,leading to nanorods and nanoplatelets based on the alkali metal ions used.Given their outstanding effects and widely applicable synthetic conditions,alkali metal carboxylates offer new possibilities for designing efficient methods for synthesizing CQDs.
基金funded by the Danish Strategic Research Council(No.DSF-10-93456,FENAMI Project)the Fundamental Research Funds for the Central Universities(No.JUSRP1042)+2 种基金the Open Project Program of Key Laboratory of Eco-textiles,Ministry of Education,Jiangnan University(No.KLET1202)the National Natural Science Foundation of China under Grant No.31201134National High-tech R&D Program of China(863 Program,No. 2012AA030313)
文摘This study aims at preparing water soluble aspartic acid （ASP） modified CdTe quantum dots with tunable fluorescence emission controlled by reaction time. The size of the synthesized CdTe quantum dots was evaluated using transmission electron microscope （TEM） and also calculated based on their UV-vis spectra. The optical properties of TGA-CdTe quantum dots were characterized by UV-vis and fluorescence （FL） spectroscopy. The red-shift in the UV-vis absorption and FL emission with the increase of reaction time was observed. The biocompatibility examination indicated that the ASP modified CdTe QDs had low cytotoxicity.
