A new facile method for preparing water-soluble near-infrared (NIR)-emitting PbS quantum dots (QDs) is proposed by using N-acetyl-L-cysteine (NAC, a derivate of L-cysteine) as its stabilizer. The influence of th...A new facile method for preparing water-soluble near-infrared (NIR)-emitting PbS quantum dots (QDs) is proposed by using N-acetyl-L-cysteine (NAC, a derivate of L-cysteine) as its stabilizer. The influence of the precursor Pb/S molar ratio, the Pb/NAC molar ratio, and the pH of original solution on optical properties is explored. Results show that aqueous PbS QDs with strong NIR fluorescence can be prepared and their photoluminescence emission peaks can be tuned from 895 nm to 970 nm. Studies indicate that such aqueous QDs have a potential application in biomedical imaging, especially in noninvasive in vivo fluorescence imaging. In addition, the resulting PbS QDs are further characterized by a transmission electron microscopy and X-ray diffraction analysis.展开更多
Semiconductor quantum dots(QDs) were used for labeling many biomacromolecules and small molecules,but it remains a challenge to couple it with short active peptides without any limitation,which play critical roles in ...Semiconductor quantum dots(QDs) were used for labeling many biomacromolecules and small molecules,but it remains a challenge to couple it with short active peptides without any limitation,which play critical roles in many physiological processes.Several coupling methods known about QDs and short peptides have some limitations.In this research,we report a method for the synthesis of QDs labeled peptides to be appropriate to any short peptide.The QDs(CdTe)-labeled short peptides were verified and characterized by RP-HPLC.The result shows that the surface of the T cell treated with QDs-TP5 emits yellow fluoresence.These results indicate that QDs-TP5 tends to aggregate on the surface of T cells.They were applied to monitoring the specific binding between the immune peptides and T cell surface receptors.The binding and the resultant fluorescence were observed and monitored by fluorescence microscope in vitro.The QDs-labeled immune peptides provide a powerful method for studying the immune modulating activity of TP5 in vivo.展开更多
This paper reported an efficient and rapid method to produce highly monodispersed CdSe quantum dots (QDs), in which the traditional trioctylphosphine oxide (TOPO) was replaced by paraffin liquid as solvent and oleic a...This paper reported an efficient and rapid method to produce highly monodispersed CdSe quantum dots (QDs), in which the traditional trioctylphosphine oxide (TOPO) was replaced by paraffin liquid as solvent and oleic acid as the reacting media. The experimental conditions and the properties of QDs had been studied in detail. The resulting samples were confirmed of uniform size distribution with transmission electronic microscopy (TEM), while UV-vis absorption and photoluminescence (PL) spectra clearly indicated that such synthesized QDs had good fluorescence properties.展开更多
The cytotoxicity and DNA damage caused by thioglycolic acid(TGA)-capped cadmium telluride(CdTe) quantum dots(QDs) to hepatocyte line HL-7702 were investigated.Cell viability was measured by 3-(4,5-dimethylthiaz...The cytotoxicity and DNA damage caused by thioglycolic acid(TGA)-capped cadmium telluride(CdTe) quantum dots(QDs) to hepatocyte line HL-7702 were investigated.Cell viability was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT) assay;DNA damage was detected by single cell gel electrophoresis(SCGE);the change of cell cycle progression was examined by propidium iodide(PI)-flow cytometry(FCM);apoptosis was measured by acridine orange/ethidium bromide(AO/EB) assay and Annexin V-FITC/PI-FCM(FITC:fluorescein isothiocyanate).The results show that the cytotoxicity induced by CdTe QDs was increased in a dose-dependent and time-dependent manner;after exposure to QDs for 24 h,as the exposure dose increased,the rate of DNA damage was significantly increased(P0.05),and the degree of DNA damage was elevated.As the dose of CdTe QDs increased,the percentage of G 0 /G 1 phase cells was significantly decreased(P0.001),while the percenttages of S and G 2 /M phases cells were significantly increased(P0.001).In AO/EB assay,apoptotic cells could be observed under a fluorescence microscope,and apoptotic rate was increased as exposure dose increased.In Annexin V-FITC/PI-FCM assay,the apoptotic rates of CdTe QDs treated groups were significantly increased compared with that of control group(P0.05).Our studies indicate that CdTe QDs could influence cell viability,and induce DNA damage,the S and G2 /M phases arrest and apoptosis of HL-7702.展开更多
In this work the enhanced molecularly imprinted optosensing material based on graphene oxide-quantum dots ( GO- QDs) was synthesized for highly selective and sensitive specific recognition of the target protein, bov...In this work the enhanced molecularly imprinted optosensing material based on graphene oxide-quantum dots ( GO- QDs) was synthesized for highly selective and sensitive specific recognition of the target protein, bovine serum albumin (BSA). Here, GO was introduced to enhance the efficiency of mass-transfer in recognition of target protein. Molecularly imprinted polymer coated GO-QDs using BSA as template (BMIP-coated GO-QDs ) exhibited a fast mass-transfer speed, which could be ascribed to the high volume of efficient surface area and high target recognition efficiency of the synthesized nanoscale device. Under optimal conditions, it was found that the BSA as target protein could remarkably quench the relative fluorescence intensity of BMIP- coated GO-QDs linearly in a concentration-dependent manner that was best described by a Stern-Volmer equation. The Ksv (Stern- Volmer constant) for template BSA was much higher than bovine hemoglobin (BHb) and lysozyme (Lyz), implying a highly selective recognition ability of the BMIP-coated GO-QDs to BSA. This enhanced fluorescent nanoscale device may provide opportunities to develop a system that is efficient and effective and has potential in the design of highly effective fluorescent receptor for recognition of target protein in Droteomics studies.展开更多
A simple chemical-etching approach is used to prepare the silicon carbide quantum dots (QDs). The raw materials of silicon carbide (SiC) with homogeneous nanoparticles fabricated via self-propagating combustion synthe...A simple chemical-etching approach is used to prepare the silicon carbide quantum dots (QDs). The raw materials of silicon carbide (SiC) with homogeneous nanoparticles fabricated via self-propagating combustion synthesis are corroded in mixture etchants of nitric and hydrofluoric acid. After sonication and chromatography in the ultra-gravity field for the etched products, aqueous solution with QDs can be obtained. The microstructure evolution of raw particles and optical properties of QDs were measured. Different organophilic groups on the surface like carboxyl, oxygroup, and hyfroxy were produced in the process of etching. Fluorescent labeling and imaging for living cells of Aureobasidium pulluans were investigated. The results indicated that SiC QDs were not cytotoxic and could stably label due to the conjugation between organophilic groups of QDs and specific protein of cells, it can be utilized for fluorescent imaging and tracking cells with in vivo and long-term-distance. Moreover, mechanism and specificity of mark were also analyzed.展开更多
Photocatalytic water splitting is beneficial for the effective mitigation of global energy and environmental crises.Owing to multi-exciton generation,impressive light harvesting,and excellent photochemical properties,...Photocatalytic water splitting is beneficial for the effective mitigation of global energy and environmental crises.Owing to multi-exciton generation,impressive light harvesting,and excellent photochemical properties,the quantum dot(QD)-based catalysts reveal a considerable potential in photocatalytic hydrogen(H_(2))production compared with bulk competitors.In this review,we summarize the recent advances in QDs for photocatalytic H_(2) production by enumerating different synthetic and characterization strategies for QDs.Various QDs-based photocatalysts are introduced and summarized in categories,and the role of different QDs in varied systems,as well as the mechanism and key factors that enhance the photocatalytic H_(2) generation performance,is discussed.Finally,conclusions and future perspectives in the exploration of highly efficient QDs-based photocatalysts for innovative applications are highlighted.展开更多
Electrospun porous films doped with the green-synthesized CdSe quantum dots were synthesized. Glycerol was chosen to prepare the quantum dots ( QDs), with the highest quantum yield of 78.28%. Polycaprolactone (PCL...Electrospun porous films doped with the green-synthesized CdSe quantum dots were synthesized. Glycerol was chosen to prepare the quantum dots ( QDs), with the highest quantum yield of 78.28%. Polycaprolactone (PCL) was electrospun with CdSe QDs to avoid the QDs' toxicity and improve the QDs' cytocompatibility. The electrospun QDs-doped films preserve the original QDs' fluorescence. Pores can be detected from the SEM of the films, predicting the possibility of loading drugs in the cancer therapy. The cell proliferation assay shows excellent cytocompatibility of the eletrospun CdSe-QDs-doped films. The present eletrospun CdSe- QDs-doped porous films are cytocompatibale, highly-fluorescent and ootential to load drugs in cancer therapy.展开更多
A novel quantum dots (QDs) optical fiber amplifier was proposed and demonstrated. It was fabricated by dipcoating the PbSe QDs doped sol onto the taper region of fiber coupler. The PbSe QDs was synthesized according...A novel quantum dots (QDs) optical fiber amplifier was proposed and demonstrated. It was fabricated by dipcoating the PbSe QDs doped sol onto the taper region of fiber coupler. The PbSe QDs was synthesized according to a colloidal method. A lower refractive index sol was also synthesized as the host of PbSe QDs. A standard single mode fiber was used to make the fusion tapered fiber coupler which had double input and output ports. With the simple structure, a signal and a pump can be injected into the amplifier and excite the PbSe QDs through evanescent wave. The experimental results indicated that the amplified light wave was observed at 1 550 nm wavelength with 980 nm .wavelength laser diode as pump.展开更多
Novel CdTe/CdS quantum dots(QDs)coated with a hybrid of SiO_2 and ZnS were fabricated through a simple two-step approach.The hybrid SiO_2/ZnS coated CdTe/CdS quantum dots was characterized by transmission electron mic...Novel CdTe/CdS quantum dots(QDs)coated with a hybrid of SiO_2 and ZnS were fabricated through a simple two-step approach.The hybrid SiO_2/ZnS coated CdTe/CdS quantum dots was characterized by transmission electron microscopy(TEM),UV and fluorescence spectrometer.Results indicated that the core-shell structure gave the QDs outstanding photoluminescence properties,includinganarrowphotoluminescencespectrum,high photoluminescence(PL)quantum yield and long emission lifetime(average PL lifetime of increased from 26.4 ns to 49.1 ns).Cellular studies showed the QDs had good cytocompatibility with Hela cells as determined by the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide(MTT)assay after coating SiO_2/ZnS,and also proved the feasibility of using the hybrid SiO_2/ZnS coated QDs as optical probes for in vitro cell imaging.The synthesis method of QDs is highly promising for the production of robust and functional optical probes for bio-imaging and sensing applications.展开更多
To improve the stability and luminescence properties of CsPbBr_(3)QDs,we proposed a new core-shell structure for CsPbBr_(3)/CdSe/Al quantum dots(QDs).By using a simple method of ion layer adsorption and a reaction met...To improve the stability and luminescence properties of CsPbBr_(3)QDs,we proposed a new core-shell structure for CsPbBr_(3)/CdSe/Al quantum dots(QDs).By using a simple method of ion layer adsorption and a reaction method,CdSe and A1 were respectively packaged on the surface of CsPbBr_(3)QDs to form the core-shell CsPbBr_(3)/CdSe/Al QDs.After one week in a natural environment,the photoluminescence quantum yields of CsPbBr_(3)/CdSe/Al QDs were greater than 80%,and the PL intensity remained at 71%of the original intensity.Furthermore,the CsPbBr_(3)/CdSe/Al QDs were used as green emitters for white light-emitting diodes(LEDs),with the LEDs spectrum covering 129%of the national television system committee(NTSC)standard color gamut.The core-shell structure of QDs can effectively improve the stability of CsPbBr_(3)QDs,which has promising prospects in optoelectronic devices.展开更多
We theoretically investigate the single- and few-electron states in deformed HgTe quantum dots (QDs) with an inverted band structure using the full configuration interaction method. For the circular and deformed QD,...We theoretically investigate the single- and few-electron states in deformed HgTe quantum dots (QDs) with an inverted band structure using the full configuration interaction method. For the circular and deformed QD, it is found that the energy of edge states is robust against the shape from the circular QD in various elliptic ones. For the few electron states, electrons will firstly fill the edge states localized at the short axis, then the states localized at the long axis of the QD before filling the bulk states. The filling of the edge states can be controlled by tuning the dot size or the deformation of the geometry of the HgTe QD, respectively.展开更多
CdTe/CdS quantum dots(QDs) are fabricated on Si nanowires(NWs) substrates with and without Au nanoparticles(NPs). The formation of Au NPs on Si NWs can be certified as shown in scanning electron microscopy image...CdTe/CdS quantum dots(QDs) are fabricated on Si nanowires(NWs) substrates with and without Au nanoparticles(NPs). The formation of Au NPs on Si NWs can be certified as shown in scanning electron microscopy images. The optical properties of samples are also investigated. It is interesting to find that the photoluminescence(PL) intensity of Cd Te/Cd S QD films on Si nanowire substrates with Au NPs is significantly increased,which can reach 8-fold higher than that of samples on planar Si without Au NPs. The results of finite-difference time-domain simulation indicate that Au NPs induce stronger localization of electric field and then boost the PL intensity of QDs nearby. Furthermore, the time-resolved luminescence decay curve shows the PL lifetime, which is about 5.5 ns at the emission peaks of QD films on planar, increasing from 1.8 ns of QD films on Si NWs to4.7 ns after introducing Au NPs into Si NWs.展开更多
A highly efficient single-photon source based on a semiconductor quantum dot (QD) is a promising candidate in quantum information processing. We report a single-photon source based on self-assembled GaAs QDs in nano...A highly efficient single-photon source based on a semiconductor quantum dot (QD) is a promising candidate in quantum information processing. We report a single-photon source based on self-assembled GaAs QDs in nanowires with an extraction efficiency of 14%. The second-order correlation function g(2) (0) at saturate excitation power is estimated to be 0.28. The measured polarization of QD emission depends on the geometric relations between the directions of PL collection and the long axis of nanowires.展开更多
Room-temperature negative differential resistance (NDR) has been observed in different types of organic materials. However, detailed study on the influence of the organic material on NDR performance is still scarce....Room-temperature negative differential resistance (NDR) has been observed in different types of organic materials. However, detailed study on the influence of the organic material on NDR performance is still scarce. In this work, room-temperature NDR & observed when CdSe quantum dot (QD) modified ITO is used as the electrode. Furthermore, material dependence of the NDR performance is observed by selecting materials with different charge transporting properties as the active layer, respectively. A peak-to-valley current ratio up to 9 is observed. It is demonstrated that the injection barrier between ITO and the organic active layer plays a decisive role for the device NDR performance. The influence of the aggregation state of CdSe QDs on the NDR performance is also studied, which indicates that the NDR is caused by the resonant tunneling process in the ITO/CdSe QD/organic active layer structure.展开更多
基金Supported by the National Natural Science Foundation of China (30800257,30700799)the Scien-tific Research Starting Foundation for Introduced Talented Persons of China Pharmaceutical University~~
文摘A new facile method for preparing water-soluble near-infrared (NIR)-emitting PbS quantum dots (QDs) is proposed by using N-acetyl-L-cysteine (NAC, a derivate of L-cysteine) as its stabilizer. The influence of the precursor Pb/S molar ratio, the Pb/NAC molar ratio, and the pH of original solution on optical properties is explored. Results show that aqueous PbS QDs with strong NIR fluorescence can be prepared and their photoluminescence emission peaks can be tuned from 895 nm to 970 nm. Studies indicate that such aqueous QDs have a potential application in biomedical imaging, especially in noninvasive in vivo fluorescence imaging. In addition, the resulting PbS QDs are further characterized by a transmission electron microscopy and X-ray diffraction analysis.
文摘Semiconductor quantum dots(QDs) were used for labeling many biomacromolecules and small molecules,but it remains a challenge to couple it with short active peptides without any limitation,which play critical roles in many physiological processes.Several coupling methods known about QDs and short peptides have some limitations.In this research,we report a method for the synthesis of QDs labeled peptides to be appropriate to any short peptide.The QDs(CdTe)-labeled short peptides were verified and characterized by RP-HPLC.The result shows that the surface of the T cell treated with QDs-TP5 emits yellow fluoresence.These results indicate that QDs-TP5 tends to aggregate on the surface of T cells.They were applied to monitoring the specific binding between the immune peptides and T cell surface receptors.The binding and the resultant fluorescence were observed and monitored by fluorescence microscope in vitro.The QDs-labeled immune peptides provide a powerful method for studying the immune modulating activity of TP5 in vivo.
基金Project supported by the National Natural Science Foundation of China (No. 30672017)the Swedish Foundation for Strategic Research (SSF)
文摘This paper reported an efficient and rapid method to produce highly monodispersed CdSe quantum dots (QDs), in which the traditional trioctylphosphine oxide (TOPO) was replaced by paraffin liquid as solvent and oleic acid as the reacting media. The experimental conditions and the properties of QDs had been studied in detail. The resulting samples were confirmed of uniform size distribution with transmission electronic microscopy (TEM), while UV-vis absorption and photoluminescence (PL) spectra clearly indicated that such synthesized QDs had good fluorescence properties.
基金Supported by the Funding Project for Academic Human Resources Development in Higher Learning Institution Under the Jurisdiction of Beijing Municipality,China(No.PHR201006110)the Innovative Team Project of Beijing Education Committee,China(No.PHR201107116)
文摘The cytotoxicity and DNA damage caused by thioglycolic acid(TGA)-capped cadmium telluride(CdTe) quantum dots(QDs) to hepatocyte line HL-7702 were investigated.Cell viability was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT) assay;DNA damage was detected by single cell gel electrophoresis(SCGE);the change of cell cycle progression was examined by propidium iodide(PI)-flow cytometry(FCM);apoptosis was measured by acridine orange/ethidium bromide(AO/EB) assay and Annexin V-FITC/PI-FCM(FITC:fluorescein isothiocyanate).The results show that the cytotoxicity induced by CdTe QDs was increased in a dose-dependent and time-dependent manner;after exposure to QDs for 24 h,as the exposure dose increased,the rate of DNA damage was significantly increased(P0.05),and the degree of DNA damage was elevated.As the dose of CdTe QDs increased,the percentage of G 0 /G 1 phase cells was significantly decreased(P0.001),while the percenttages of S and G 2 /M phases cells were significantly increased(P0.001).In AO/EB assay,apoptotic cells could be observed under a fluorescence microscope,and apoptotic rate was increased as exposure dose increased.In Annexin V-FITC/PI-FCM assay,the apoptotic rates of CdTe QDs treated groups were significantly increased compared with that of control group(P0.05).Our studies indicate that CdTe QDs could influence cell viability,and induce DNA damage,the S and G2 /M phases arrest and apoptosis of HL-7702.
文摘In this work the enhanced molecularly imprinted optosensing material based on graphene oxide-quantum dots ( GO- QDs) was synthesized for highly selective and sensitive specific recognition of the target protein, bovine serum albumin (BSA). Here, GO was introduced to enhance the efficiency of mass-transfer in recognition of target protein. Molecularly imprinted polymer coated GO-QDs using BSA as template (BMIP-coated GO-QDs ) exhibited a fast mass-transfer speed, which could be ascribed to the high volume of efficient surface area and high target recognition efficiency of the synthesized nanoscale device. Under optimal conditions, it was found that the BSA as target protein could remarkably quench the relative fluorescence intensity of BMIP- coated GO-QDs linearly in a concentration-dependent manner that was best described by a Stern-Volmer equation. The Ksv (Stern- Volmer constant) for template BSA was much higher than bovine hemoglobin (BHb) and lysozyme (Lyz), implying a highly selective recognition ability of the BMIP-coated GO-QDs to BSA. This enhanced fluorescent nanoscale device may provide opportunities to develop a system that is efficient and effective and has potential in the design of highly effective fluorescent receptor for recognition of target protein in Droteomics studies.
文摘A simple chemical-etching approach is used to prepare the silicon carbide quantum dots (QDs). The raw materials of silicon carbide (SiC) with homogeneous nanoparticles fabricated via self-propagating combustion synthesis are corroded in mixture etchants of nitric and hydrofluoric acid. After sonication and chromatography in the ultra-gravity field for the etched products, aqueous solution with QDs can be obtained. The microstructure evolution of raw particles and optical properties of QDs were measured. Different organophilic groups on the surface like carboxyl, oxygroup, and hyfroxy were produced in the process of etching. Fluorescent labeling and imaging for living cells of Aureobasidium pulluans were investigated. The results indicated that SiC QDs were not cytotoxic and could stably label due to the conjugation between organophilic groups of QDs and specific protein of cells, it can be utilized for fluorescent imaging and tracking cells with in vivo and long-term-distance. Moreover, mechanism and specificity of mark were also analyzed.
基金Taishan Youth Scholar Program of Shandong ProvinceNational Natural Science Foundation of China,Grant/Award Numbers:21972058,21975110,22088102,51825205+3 种基金Postgraduate Practice Research Innovation Program of Jiangsu Province,Grant/Award Number:SJCX21_1707CAS Project for Young Scientists in Basic Research,Grant/Award Number:YSBR‐004DNL Cooperation Fund,CAS,Grant/Award Number:DNL202016National Key Projects for Fundamental Research and Development of China,Grant/Award Number:2018YFB1502002。
文摘Photocatalytic water splitting is beneficial for the effective mitigation of global energy and environmental crises.Owing to multi-exciton generation,impressive light harvesting,and excellent photochemical properties,the quantum dot(QD)-based catalysts reveal a considerable potential in photocatalytic hydrogen(H_(2))production compared with bulk competitors.In this review,we summarize the recent advances in QDs for photocatalytic H_(2) production by enumerating different synthetic and characterization strategies for QDs.Various QDs-based photocatalysts are introduced and summarized in categories,and the role of different QDs in varied systems,as well as the mechanism and key factors that enhance the photocatalytic H_(2) generation performance,is discussed.Finally,conclusions and future perspectives in the exploration of highly efficient QDs-based photocatalysts for innovative applications are highlighted.
基金Shanghai Leading Academic Discipline Project,China,Shanghai Key Laboratory Project,China,Doctoral Fund of Ministry of Education of China,National Natural Science Foundation of China
文摘Electrospun porous films doped with the green-synthesized CdSe quantum dots were synthesized. Glycerol was chosen to prepare the quantum dots ( QDs), with the highest quantum yield of 78.28%. Polycaprolactone (PCL) was electrospun with CdSe QDs to avoid the QDs' toxicity and improve the QDs' cytocompatibility. The electrospun QDs-doped films preserve the original QDs' fluorescence. Pores can be detected from the SEM of the films, predicting the possibility of loading drugs in the cancer therapy. The cell proliferation assay shows excellent cytocompatibility of the eletrospun CdSe-QDs-doped films. The present eletrospun CdSe- QDs-doped porous films are cytocompatibale, highly-fluorescent and ootential to load drugs in cancer therapy.
基金Project supported by the Innovation Program of Shanghai Municipal Education Commission (Grant No.10YZ12)the Science and Technology of Commission of Shanghai Municipality (Grant No.0952nm06800)the Shanghai Leading Academic Discipline Project (Grant No.S30108)
文摘A novel quantum dots (QDs) optical fiber amplifier was proposed and demonstrated. It was fabricated by dipcoating the PbSe QDs doped sol onto the taper region of fiber coupler. The PbSe QDs was synthesized according to a colloidal method. A lower refractive index sol was also synthesized as the host of PbSe QDs. A standard single mode fiber was used to make the fusion tapered fiber coupler which had double input and output ports. With the simple structure, a signal and a pump can be injected into the amplifier and excite the PbSe QDs through evanescent wave. The experimental results indicated that the amplified light wave was observed at 1 550 nm wavelength with 980 nm .wavelength laser diode as pump.
基金The Fundamental Research Funds for the Central Universities,China(No.2232015D3-15)Shanghai Natural Science Foundation,China(No.14ZR1401300)“111 Project”Biomedical Textile Materials Science and Technology,China(No.B07024)
文摘Novel CdTe/CdS quantum dots(QDs)coated with a hybrid of SiO_2 and ZnS were fabricated through a simple two-step approach.The hybrid SiO_2/ZnS coated CdTe/CdS quantum dots was characterized by transmission electron microscopy(TEM),UV and fluorescence spectrometer.Results indicated that the core-shell structure gave the QDs outstanding photoluminescence properties,includinganarrowphotoluminescencespectrum,high photoluminescence(PL)quantum yield and long emission lifetime(average PL lifetime of increased from 26.4 ns to 49.1 ns).Cellular studies showed the QDs had good cytocompatibility with Hela cells as determined by the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide(MTT)assay after coating SiO_2/ZnS,and also proved the feasibility of using the hybrid SiO_2/ZnS coated QDs as optical probes for in vitro cell imaging.The synthesis method of QDs is highly promising for the production of robust and functional optical probes for bio-imaging and sensing applications.
基金supported by the National Natural Science Foundation of China(Grant Nos.61865002 and 62065002)Project of Outstanding Young Scientific and Technological Talents of Guizhou Province,China(Grant No.QKEPTRC[2019]5650)+1 种基金Guizhou Province Science and Technology Platform and Talent Team Project,China(Grant No.QKEPTRC[2018]5616)Central Government of China Guiding Local Science and Technology Development Plan(Grant No.QKZYD[2017]4004)。
文摘To improve the stability and luminescence properties of CsPbBr_(3)QDs,we proposed a new core-shell structure for CsPbBr_(3)/CdSe/Al quantum dots(QDs).By using a simple method of ion layer adsorption and a reaction method,CdSe and A1 were respectively packaged on the surface of CsPbBr_(3)QDs to form the core-shell CsPbBr_(3)/CdSe/Al QDs.After one week in a natural environment,the photoluminescence quantum yields of CsPbBr_(3)/CdSe/Al QDs were greater than 80%,and the PL intensity remained at 71%of the original intensity.Furthermore,the CsPbBr_(3)/CdSe/Al QDs were used as green emitters for white light-emitting diodes(LEDs),with the LEDs spectrum covering 129%of the national television system committee(NTSC)standard color gamut.The core-shell structure of QDs can effectively improve the stability of CsPbBr_(3)QDs,which has promising prospects in optoelectronic devices.
基金Supported by the National Natural Science Foundation of China under Grant No 11434010the National Basic Research Program of China under Grant No 2011CB922204
文摘We theoretically investigate the single- and few-electron states in deformed HgTe quantum dots (QDs) with an inverted band structure using the full configuration interaction method. For the circular and deformed QD, it is found that the energy of edge states is robust against the shape from the circular QD in various elliptic ones. For the few electron states, electrons will firstly fill the edge states localized at the short axis, then the states localized at the long axis of the QD before filling the bulk states. The filling of the edge states can be controlled by tuning the dot size or the deformation of the geometry of the HgTe QD, respectively.
基金Supported by the Qing Lan Project of the Higher Education Institutions of Jiangsu Province,Qing Lan Project of Yangzhou Polytechnic Institute,the Natural Science Foundation of Yangzhou City under Grant No YZ2016123the National Natural Science Foundation of China under Grant No 61376004
文摘CdTe/CdS quantum dots(QDs) are fabricated on Si nanowires(NWs) substrates with and without Au nanoparticles(NPs). The formation of Au NPs on Si NWs can be certified as shown in scanning electron microscopy images. The optical properties of samples are also investigated. It is interesting to find that the photoluminescence(PL) intensity of Cd Te/Cd S QD films on Si nanowire substrates with Au NPs is significantly increased,which can reach 8-fold higher than that of samples on planar Si without Au NPs. The results of finite-difference time-domain simulation indicate that Au NPs induce stronger localization of electric field and then boost the PL intensity of QDs nearby. Furthermore, the time-resolved luminescence decay curve shows the PL lifetime, which is about 5.5 ns at the emission peaks of QD films on planar, increasing from 1.8 ns of QD films on Si NWs to4.7 ns after introducing Au NPs into Si NWs.
基金Supported by the National Key Basic Research Program of China under Grant No 2013CB922304the National Natural Science Foundation of China under Grant Nos 11474275 and 11204297
文摘A highly efficient single-photon source based on a semiconductor quantum dot (QD) is a promising candidate in quantum information processing. We report a single-photon source based on self-assembled GaAs QDs in nanowires with an extraction efficiency of 14%. The second-order correlation function g(2) (0) at saturate excitation power is estimated to be 0.28. The measured polarization of QD emission depends on the geometric relations between the directions of PL collection and the long axis of nanowires.
基金Supported by the National Natural Science Foundation of China under Grant Nos 61106123 and 61275034the National Basic Research Program of China under Grant No 2013CB328705
文摘Room-temperature negative differential resistance (NDR) has been observed in different types of organic materials. However, detailed study on the influence of the organic material on NDR performance is still scarce. In this work, room-temperature NDR & observed when CdSe quantum dot (QD) modified ITO is used as the electrode. Furthermore, material dependence of the NDR performance is observed by selecting materials with different charge transporting properties as the active layer, respectively. A peak-to-valley current ratio up to 9 is observed. It is demonstrated that the injection barrier between ITO and the organic active layer plays a decisive role for the device NDR performance. The influence of the aggregation state of CdSe QDs on the NDR performance is also studied, which indicates that the NDR is caused by the resonant tunneling process in the ITO/CdSe QD/organic active layer structure.