- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Designer cell-self-implemented labeling of microvesicles in situ with the intracellular-synthesized quantum dots
摘要： Cell-derived microvesicles (MVs) are secreted from almost all kinds of mammalian cells into the extracellular space, and play crucial roles in intercellular communication and transporting biomolecules between cells. However, there is a great challenge for visualizing and monitoring of MVs’ bio-behaviors due to the limitations of existing labeling methods. Herein, we report the first paradigm of designer cell-self-implemented labeling of MVs secreted from living mammalian MCF-7 cells in situ using the intracellular-synthesized fluorescent quantum dots (QDs) during the formation of MVs. By elaborately coupling intracellular biochemical reactions and metabolism pathways, the MCF-7 cells can be illuminated brightly by intracellular-biosynthesized fluorescent CdSe QDs. Simultaneously, intracellular-synthesized QDs can be in situ encapsulated by the secreted MVs budding from the plasma membrane of the fluorescing cells to label the MVs with an efficiency of up to 89.9%. The whole labeling process skillfully combines designer precise cell-tuned intricate synthesis of CdSe QDs with mild in-situ labeling via cell-self-implementation just after feeding the cell with suitable chemicals, which is structure- or function-nondestructive and much more straightforward and milder than those by chemical conjugation or indirect encapsulation with conventional fluorogenic labels.
关键词： quantum dot,cell-derived microvesicles,live cell synthesis,cell-self-implementation,in situ labeling
更新于2025-09-23 15:19:57
-
Dynamics of pulse amplification in tapered-waveguide quantum-dot semiconductor optical amplifiers
摘要： Tapered-waveguide quantum dot semiconductor optical amplifiers (TW-QDSOAs) have been modeled using numerical calculation of the rate and propagation equations in this article and the amplification characteristics and dynamics of pulse propagation in non-tapered QDSOA, linear, and exponential TW-QDSOA structures have been studied and compared in detail. It has been found that TW-QDSOAs apply less distortion to the amplified pulse and have greater optical gain than non-tapered QDSOA. In TW-QDSOAs, the amplified pulse becomes much less broadening and this amount is negligible, therefore the pulse bit rate can be increased. While the amplified pulse in a non-tapered QDSOA is much broadening than the TW-QDSOAs. The carrier density distribution and dependency of the amplifier gain to the output energy for both non-tapered and tapered structures have been studied. The carrier density and gain in non-tapered QDSOA decreases more than TW-QDSOAs, indicating that the tapered amplifiers are saturated at higher input energies. Our obtained results agree well with those previously obtained for conventional tapered amplifiers.
关键词： Quantum dot semiconductor optical amplifier,tapered QDSOA,gain saturation
更新于2025-09-23 15:19:57
-
Graphene quantum dots doped ZnO superstructure (ZnO superstructure/GQDs) for weak UV intensity photodetector application
摘要： Usually, the photoresponse performances of zinc oxide based ultraviolet (UV) photodetector can be enhanced by improving the nanostructure of zinc oxide. Here, we demonstrate a kind of weak ultraviolet intensity photodetector which bases on ZnO superstructure doped with graphene quantum dots (ZnO superstructure/GQDs). The ZnO superstructure includes a ZnO nanoflower on the top of ZnO nanorod. The nanoflower has large specific surface area that is favor to the absorption of weak UV light, and the nanorod provides a good route for carriers transport. Also, the GQDs can assist the absorption of UV and the transport of carriers. The photo-response performance of the ZnO superstructure/GQDs we measured is obtained at a working bias of 3 V and an irradiate condition of 50 μW/cm2, under the excitation wavelength 365 nm. The results show that ZnO superstructure/GQDs has a low dark current (40 nA) and a good photocurrent (2.1 μA) in a low irradiation and power supply condition, and we calculate the current ratio of on/off is about 52.5 times. Further, we discuss in-depth the synthesis mechanism of ZnO superstructure and the transport mechanism of photo-generated carriers in this paper. At the same time, we develop a UV signal acquisition and voltage conversion system, which proves the practical application reference of ZnO superstructure/GQDs for weak UV intensity photodetector.
关键词： Weak ultraviolet detector,Practical application,Graphene quantum dot doping,ZnO superstructure
更新于2025-09-23 15:19:57
-
Application of ZnxLayFezO4 spinel nanomaterial in quantum dot sensitized solar cells
摘要： A novel inorganic spinel nanomaterial with formula Zn0.6093La1.3979Fe0.8650O4 (ZLF) was synthesized and characterized by the X-ray photoelectron spectroscopy (XPS) to determine its stoichiometric formula. The Filed-Emission Scanning Electron Microscopy (FE-SEM) and Transmission Electron Microscopy (TEM) images displayed that the ZLF nanoparticles (NPs) had a very fine spherical morphology and average particle sizes in the range of about 5–30 nm. Quantum dot-sensitized solar cells (QDSSCs) were fabricated using the ZLF NPs which were incorporated into the TiO2 pastes of photoanodes. The photoluminescence (PL) spectra of the ZLF NPs and the photoanodes exhibited three maxima plus a weak broad peak at around 420, 460 and 485 plus 530 nm. The lowest intensity of the PL peak for the CdSe cell fabricated using 0.4 %ZLF suggested that it had the least charge recombination and the easiest electron transfer. The photovoltaic parameters of the optimized champion cell containing 0.4 % of ZLF NPs (η = 3.50 %, JSC = 13.11 mA/cm2, VOC = 0.58 V) were boosted compared to those of the ZLF-free reference cell (η = 2.18 %, JSC = 8.70 mA/cm2, VOC = 0.57 V) demonstrating a high improvement of approximately 61 % in the efficiency. The Electrochemical Impedance Spectra (EIS) revealed that the charge transfer resistance (RCT) in the optimum cell was dropped by adding the ZLF NPs into the TiO2 compared to that of the reference ZLF-free cell. Thus, upon adding 0.4 %ZLF, appropriate photocurrent efficiency was attained for the QDSSC because the ZLF nanoparticles were used in a minimum amount in order to speed up the electron transport, decline the recombination and enhance the cell efficiency.
关键词： Photoluminescence spectra,Spectra,ZnLaFeO4nanoparticles,Quantum dot sensitized solar cells,Electrochemical impedance (EIS),XPS
更新于2025-09-23 15:19:57
-
Orbital Tuning of Tunnel Coupling in InAs/InP Nanowire Quantum Dots
摘要： We report results on the control of barrier transparency in InAs/InP nanowire quantum dots via the electrostatic control of the device electron states. Recent works demonstrated that barrier transparency in this class of devices displays a general trend just depending on the total orbital energy of the trapped electrons. We show that a qualitatively different regime is observed at relatively low filling numbers, where tunneling rates are rather controlled by the axial configuration of the electron orbital. Transmission rates versus filling are further modified by acting on the radial configuration of the orbitals by means of electrostatic gating, and the barrier transparency for the various orbitals is found to evolve as expected from numerical simulations. The possibility to exploit this mechanism to achieve a controlled continuous tuning of the tunneling rate of an individual Coulomb blockade resonance is discussed.
关键词： quantum dot,InAs/InP,nanowire,Coulomb blockade,tunnel barrier,electron tunneling rate
更新于2025-09-23 15:19:57
-
AIP Conference Proceedings [AIP Publishing THE 7TH INTERNATIONAL CONFERENCE ON APPLIED SCIENCE AND TECHNOLOGY (ICAST 2019) - Karbala City, Iraq (27–28 March 2019)] THE 7TH INTERNATIONAL CONFERENCE ON APPLIED SCIENCE AND TECHNOLOGY (ICAST 2019) - Chaos synchronization in quantum dot semiconductor lasers with negative optoelectronic feedback
摘要： Chaos synchronization is investigated in quantum dot semiconductor lasers with negative optoelectronic feedback. Depending on the coupling strength between transmitter and receiver quantum dot semiconductor Laser. Synchronization happens when the coupling strength to the receiver matches the feedback strength to the transmitter, where the receiver output reproduces the output of the transmitter regardless of the presence of channel distortion or an encoded message. when feedback strength of transmitter, receiver quantum dot semiconductor Laser and coupling feedback strength are equal (- 0.3), time delay of transmitter, receiver quantum dot semiconductor Laser and coupling are sensitive to synchronization.
关键词： Chaos synchronization,Quantum dot semiconductor lasers,Negative optoelectronic feedback
更新于2025-09-23 15:19:57
-
Equivalent Circuit Parameters of Hybrid Quantum-Dot Solar Cells
摘要： We experimentally investigate the equivalent circuit parameters of hybrid quantum-dot (QD) solar cells consisted of InAs/GaAs and GaSb/GaAs QDs. The hybrid QD solar cell samples are fabricated by stacking one pair and three pairs of InAs/GaAs and GaSb/GaAs QD layers. Four equivalent circuit models are applied to fit the experimentally obtained current-voltage characteristics of the investigated samples. The relevant circuit parameters are photocurrent, reverse saturation current, diode ideality factor, series resistance, and shunt resistance. The best fitted model of all samples contains both series and shunt resistances. According to the fitting result, the diode ideality factor of 2, which indicates the dominant recombination current, is always obtained. Comparing the extracted parameters from two single-pair hybrid QD solar cells, the effects of structural stacking sequence can be discussed in term of light absorption and carrier storage properties. We have found that an increase of stacking number from one pair to three pairs deteriorates the solar cell performance. This might be caused by an excessive total QD layer thickness or a presence of dislocation defects in that sample.
关键词： Parameter Extraction,Current-Voltage Characteristics,Solar Cell,Quantum Dot
更新于2025-09-23 15:19:57
-
Aharonov-Bohm Interferometer in a T-Shaped Quantum Dot Embedded in Majorana Bound States
摘要： We theoretically study the spin-dependent transport properties of an Aharonov-Bohm (AB) interferometer composed by a T-shaped quantum dot (QD) embedded in Majorana bound states (MBS). We use the equation of motion method to calculate the conductance across the interferometer. We note that the conductance exhibits sensitive dependence on the MBS-QD coupling strength as well as the polarization strength of the leads when the phase factor of AB ring changes periodically. The conductance shows a transition from resonance to anti-resonance when the MBS-QD coupling strength changes from small to large. Also, there is di?erent p-dependence conductance when the leads alignment changes from parallel to anti-parallel. These ?ndings suggest that such a model could be used for a sensitive detection of MBS interactions, exploiting the high sensitivity of conductance to the AB phase in the interferometer.
关键词： quantum dot,Majorana bound states,Aharonov-Bohm e?ect
更新于2025-09-23 15:19:57
-
Single-electron current gain in a quantum dot with three leads
摘要： The conductance through a quantum dot (QD) between a source and a drain electrode is usually controlled electrostatically by a nearby gate electrode. A periodic modulation of the conductance versus gate voltage is observed, swapping between Coulomb blockade and single-electron tunneling. By controlling the Fermi level of a third (‘base’) lead attached to the QD, we were able to switch a single-electron current from source to drain, exceeding the single-electron current to or from the base lead. A simple model is presented revealing the role of ground- and excited states within the QD for this dynamic operation of a single-electron transistor.
关键词： electronic wavefunction,coulomb blockade,single-electron tunneling,quantum dot excitations
更新于2025-09-23 15:19:57
-
The dispersion behaviors of the tripod-type four-level cylindrical quantum dot under phenomenon of electromagnetically induced transparency
摘要： In this paper, linear and 3rd-order nonlinear group velocities of the probe laser field are investigated in a tripod-type four-level cylindrical quantum dot (TTFLCQD) with parabolic potential in electromagnetically induced transparency. The control lasers at z-polarization are applied to the system and the results are investigated. Also, linear and 3rd-order nonlinear group velocities in z-polarization are compared. The effects of parameters of TTFLCQD and control lasers on linear and 3rd-order nonlinear group velocities are explored. Finally, the results are discussed. The linear and 3rd-order nonlinear group velocities are compared at z-polarization. Furthermore, the effects of parameters of TTFLCQD and control lasers on linear and 3rd-order nonlinear group velocities are explored. Finally, the results are discussed. The linear and 3rd-order nonlinear group velocities are compared at z-polarization. Furthermore, the effects of parameters of TTFLCQD and control lasers on linear and 3rd-order nonlinear group velocities are explored. Finally, the results are discussed.
关键词： Electromagnetically induced transparency,Tripod-type four-level cylindrical quantum dot,Nonlinear group velocity,Linear group velocity,Slow light
更新于2025-09-23 15:19:57