- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Temperature-Dependent Photoluminescence in CdTe/ZnTe Triple Quantum Dots
摘要： We studied the optical properties of CdTe/ZnTe quantum dots (QDs) in single, double, and triple QD structures by measuring the temperature-dependent photoluminescence (PL). On going from the single to the triple QD structures, the PL peak position of the QDs was blue shifted. This blue-shift was attributed to compressive strain imparted by the separation layers and to material intermixing. Temperature-dependent PL measurements of the triple QD structures showed that, as the temperature increased, the PL peak intensity for the 4.5-monolayer (ML) QDs decreased less than it did for the 3.0- and the 3.5-ML QDs. The activation energy of the 4.5-ML QDs in the triple QD structures was larger than that of the corresponding 4.5-ML QDs in the single QD structures. The reason for this is that, as the temperature increases, some carriers disappear due to non-radiative recombination, but many carriers in the 3.0- and the 3.5-ML QDs move to the 4.5-ML QDs in the triple QD structures, and those carriers then undergo radiative recombination.
关键词： Cadmium telluride,Photoluminescence,Triple quantum dots,Activation energy
更新于2025-09-11 14:15:04
-
Fabrication of Ag2S quantum dots sensitized CdSe photoelectrodes and its photoelectric performance
摘要： Well-aligned wheat-like CdSe nanorods array was fabricated by electrodeposition method, which was sensitized with Ag2S quantum dots (QDs) by using successive ionic layer adsorption and reaction (SILAR) method. The combination of five successive layers Ag2S QDs with CdSe shows maximum short-circuit photocurrent density of 36.88 mA/cm2. Compared with TiO2-based photoelectrode, the wheat-like CdSe nanorods array modified with Ag2S QDs exhibit improved photoelectrochemical (PEC) performance. The main reason for the enhancement of PEC is to use narrow band-gap semiconductor CdSe instead of the conventional wide band-gap oxide as the sensitized substrate of Ag2S QDs. In addition, the synthetic nanocomposites are characterized by analytical techniques such as XRD, UV–vis absorption spectroscopy, FESEM, HRTEM, EDX, XPS and EIS. The results indicate that Ag2S QDs are well grown on the surface of CdSe photoelectrodes. Meantime, the PEC performance of CdSe photoelectrodes has also been improved.
关键词： SILAR,Ag2S,CdSe,Thin films,Quantum dots
更新于2025-09-11 14:15:04
-
Study of Charge Transfer at Quantum Dot-Graphene Interface by Raman Spectroscopy
摘要： Charge transfer at the interface is important for the optoelectronic and photochemical applications of quantum dot-two dimensional material (QD-2D) hybrids. In this work, Raman spectroscopy was exploited to characterize the CdS QD-graphene hybrids with varied thicknesses of graphene and QD layer. The selection of Raman excitation energies below the QD bandgap rules out the photoexcitation effects and thus we can focus on equilibrium charge transfer upon hybrid formation. Correlation analysis of Raman spectra shows evidences of electron transfer with concentration on the order of ~1012 cm-2, confirmed by electrical measurements. The method used in this study can be applied to characterize the interfacial interaction of various QD-2D hybrids.
关键词： hybrid interface,charge transfer,quantum dots,Raman spectroscopy,two-dimensional materials
更新于2025-09-11 14:15:04
-
Electrostatic Interaction Mediates the Formation of Vesicular Structures from Coassembly of PS- <i>b</i> -PAA with Quantum Dots
摘要： Vesicular structures of block copolymers and inorganic nanoparticles with good stability have potential applications in therapeutic drug release and bioimaging. Herein, a block copolymer of polystyrene-b-poly(acrylic acid) (PS48-b-PAA67) and water-soluble AgInS2/ZnS core/shell quantum dots (QDs) capped with gelatin and thioglycolic acid were coassembled in tetrahydrofuran by adding water. The positively charged QDs bind to negatively charged PAA segments through electrostatic interaction. Numerous vesicular structures, such as uniform bilayer vesicles, ?owerlike large compound vesicles, onionlike lamellar structures consisting of alternating PS and PAA&QD layers, and multilamellar vesicles with spaces between concentric vesicle layers were obtained from the coassembly of PS48-b-PAA67 with QDs. The binding of the positively charged QDs to the PAA block in?uenced both the intra-aggregate PAA corona conformation and the interaggregate interactions. The key parameters a?ecting the formation of these vesicular structures included the QD content, solution pH, and water addition rate. Thus, tunable vesicular structures can be prepared and regulated through this simple but e?ective coassembly method.
关键词： electrostatic interaction,vesicular structures,quantum dots,coassembly,block copolymers
更新于2025-09-11 14:15:04
-
[IEEE 2018 Asia Communications and Photonics Conference (ACP) - Hangzhou (2018.10.26-2018.10.29)] 2018 Asia Communications and Photonics Conference (ACP) - All-optical Phase Shifter and Switch Based on Microfiber Coated with Colloidal Quantum Dots
摘要： We propose an all-optical phase shifter and switch based on a microfiber coated with colloidal quantum dots, phase shift up to 5.95π is achieved, and the pump-controlled optical switch has an extinction ratio of 13dB.
关键词： optical switch,optical phase shifter,colloidal quantum dots
更新于2025-09-11 14:15:04
-
Highly Selective and Sensitive Sensing of Toxic Mercury Ions Utilizing Carbon Quantum Dot-Modified Glassy Carbon Electrode
摘要： In this paper, a novel synthesis of 1 nm sized metal-free carbon quantum dots (CQDs) and their electrochemical application vis-à-vis mercury (Hg) sensing have been demonstrated. The characterization of synthesized CQDs was done by FT-IR, HR-TEM, XRD and UV–Vis analysis. Furthermore, the CQD-modified electrode shows an excellent sensing ability toward deleterious Hg ion even when 600-fold of excess of interfering ions such as Cu2+, Pb2+, Cd2+, Na+, K+, Mg2+, Ba2+, Bi2+, Fe2+, Zn2+ and Hg2+ are present. A wide linearity range (0.5–300 nM) and the lowest limit of detection (2.5 nM) are exhibited by the proposed sensor with potential scanning from ? 0.7 to + 0.7 V vs Ag/AgCl at a scan rate of 20 mV. In addition, the CQD-modified electrode displays an outstanding recovery results toward Hg in various real water samples. This study promotes new possibilities of designing various electrochemical sensors based on CQD nanocomposite.
关键词： Differential pulse voltammetry,Mercury,Cyclic voltammetry,Carbon quantum dots,Electrochemical Sensing
更新于2025-09-11 14:15:04
-
Paper sensor of curcumin by fluorescence resonance energy transfer on nitrogen-doped carbon quantum dot
摘要： Paper Sensor detection methods are attractive in wide analytical applications. Presented herein is a paper sensor and ?uorescence methods that was ?rstly developed to detect curcumin (Cur) based on ?uorescence resonance energy transfer (FRET) between nitrogen-doped carbon quantum dots (NCQDs) and Cur. The facile ?uorescent method was demonstrated to detect Cur in the range of 0e2600 mM with a detection limit of 0.13 mM. And facile paper sensor of Cur was fabricated and displayed at concentration of 0 mM, 100 mM, 200 mM, 300 mM, 400 mM, 500 mM and 600 mM, respectively. In additions, it was realized for determination of Cur in real samples including orange juice and curry solution. Compared with the reported methods, the present method is simple, rapid and sensitive for detecting Cur.
关键词： Nitrogen-doped carbon quantum dots (NCQDs),Curcumin (Cur),Fluorescence resonance energy transfer (FRET),Paper-based sensor
更新于2025-09-11 14:15:04
-
Fluorescent Nanosensors Based on Colloidal Quantum Dots for the Determination of Reduced Glutathione
摘要： A ? uorescent nanosensor based on colloidal quantum dots CdSe/ZnS modi? ed with mercaptoacetic acid to determine reduced glutathione, a non-protein compound that plays an important role in protection against oxidative stress, is developed. Sample preparation protocols that allow determination of reduced glutathione in a wide range of concentrations are presented. Dependence of the ? uorescence intensity of the system on the incubation time for a number of concentrations of reduced glutathione was measured. The possibility of using the proposed nanosensor for reliable and sensitive determination of reduced glutathione in the concentration range from 10 to 1000 μM is con? rmed. The results can be used for quantitative determination of reduced glutathione in physiological media, which is of considerable interest for medical diagnostics.
关键词： quantum dots,nanoparticles,optical nanosensors,? uorescence,reduced glutathione,disease markers,medical diagnostics
更新于2025-09-11 14:15:04
-
Near-Infrared Lead Chalcogenide Quantum Dots: Synthesis and Applications in Light Emitting Diodes
摘要： This paper reviews recent progress in the synthesis of near-infrared (NIR) lead chalcogenide (PbX; PbX=PbS, PbSe, PbTe) quantum dots (QDs) and their applications in NIR QDs based light emitting diodes (NIR-QLEDs). It summarizes the strategies of how to synthesize high efficiency PbX QDs and how to realize high performance PbX based NIR-QLEDs.
关键词： lead chalcogenide,near-infrared,quantum dots,light emitting diodes
更新于2025-09-11 14:15:04
-
Green synthesized CeO <sub/>2</sub> quantum dots: a study of its antimicrobial potential
摘要： Cerium oxide (CeO2) nanoparticles (NPs) of size ～4 nm were successfully synthesized by green synthesis method using cerium nitrate as precursor and aloe-vera leaf extract as reducing and stabilizing agent. The switching between Ce3+ and Ce4+ state by reaction with H2O2 inferred the biomedical applications of CeO2 NPs. This switching enhances due to the presence oxygen vacancies and that was con?rmed by photoluminescence spectrum. The SEM images showed spherical morphology of cubic ?uorite structured CeO2 NPs which avoids the harming of cell. In the present study, CeO2 NPs show signi?cant inhibition effect on gram negative bacteria, E. coli and P. aeruginosa which are responsible for food poisoning. Thus study analyze the synthesized CeO2 NPs as promising candidates for removal of biological pollutants and thus have great potential in the environmental remediation.
关键词： antimicrobial activity,green synthesis,quantum dots
更新于2025-09-11 14:15:04