- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
[IEEE 2019 International conference on Creative Business for Smart and Sustainable Growth (CREBUS) - Sandanski, Bulgaria (2019.3.18-2019.3.21)] 2019 International Conference on Creative Business for Smart and Sustainable Growth (CREBUS) - Innovative LED Lighting
摘要： The main innovative technologies and the principle of operation of OLED, FOLED, PHOLED, TOLED, QLED and RGB diodes are examined in this work. Luminous efficiency and the operating time dependencies on the working temperature of the diode are presented. The highly efficient light sources presented are also considered from the point of view of their energy use: for their production, use and subsequent safe disposal. In this way, an economic and environmental assessment of the benefits of their use in industry and households has been made.
关键词： Light-Emitting Diode,Efficiency,Quantum dot light emitting diode,Organic Light Emitting Diode
更新于2025-09-11 14:15:04
-
[IEEE 2019 IEEE Photonics Conference (IPC) - San Antonio, TX, USA (2019.9.29-2019.10.3)] 2019 IEEE Photonics Conference (IPC) - O-Band Quantum Dot Semiconductor Optical Amplifier Directly Grown on CMOS Compatible Si Substrate
摘要： We report the first demonstration of the O-band quantum dot semiconductor optical amplifier (QD-SOA) that is directly grown on CMOS compatible on-axis silicon substrate. The QD-SOA has a length of 3600 ????, tapered from 4 ???? to 5.5 ????, which can offer 29 dB on-chip gain and 22.8 dBm saturation output power with a minimum 7 dB fiber to fiber noise figure.
关键词： semiconductor optical amplifiers,molecular beam epitaxy,direct growth on silicon,Quantum dot devices
更新于2025-09-11 14:15:04
-
Effect of confinement potential shape on the electronic, thermodynamic, magnetic and transport properties of a GaAs quantum dot at finite temperature
摘要： The effect of the shape of the confinement potential on the electronic, thermodynamic, magnetic and transport properties of a GaAs quantum dot is studied using the power-exponential potential model with steepness parameter p. The average energy, heat capacity, magnetic susceptibility and persistent current are calculated using the canonical ensemble approach at low temperature. It is shown that for soft confinement, the average energy depends strongly on p while it is almost independent of p for hard confinement. The heat capacity is found to be independent of the shape and depth of the confinement potential at low temperatures and for the magnetic field considered. It is shown that the system undergoes a paramagnetic-diamagnetic transition at a critical value of the magnetic field. It is furthermore shown that for low values of the potential depth, the system is always diamagnetic irrespective of the shape of the potential if the magnetic field exceeds a certain value. For a range of the magnetic field, there exists a window of p values in which a re-entrant behavior into the diamagnetic phase can occur. Finally, it is shown that the persistent current in the present quantum dot is diamagnetic in nature and its magnitude increases with the depth of the dot potential but is independent of p for the parameters considered.
关键词： transport properties,thermodynamic properties,canonical ensemble approach,electronic properties,quantum dot,GaAs,paramagnetic-diamagnetic transition,persistent current,magnetic properties,power-exponential potential model,confinement potential
更新于2025-09-11 14:15:04
-
Bound-to-continuum intraband transition properties in InAs/GaAs quantum dot superlattice solar cells
摘要： We studied the interband and intraband excitation densities and the polarization dependent photocurrent in InAs/GaAs quantum dot superlattice (QDSL) solar cells with a built-in electric field of 5 kV cm?1. An almost polarization-insensitive intraband transition was observed for normal incident light, whereas slight anisotropy in the intraband transition resulted from the mixing between the conduction and valence bands. Furthermore, saturable two-color photocurrent was observed in the p–i–n solar-cell device because of electron transport in the QDSL miniband.
关键词： intraband transition,polarization anisotropy,quantum dot superlattice,solar cells,InAs/GaAs
更新于2025-09-11 14:15:04
-
Effect of CuS nanocrystalline particles on counter electrodes of multi-wall carbon nanotubes for QDSCs
摘要： CuS nanocrystalline particles are deposited into the acid-treated multi-wall carbon nanotubes (MWCNTs) film on the fluorine-doped tin oxide glass substrate through the successive ionic layer adsorption and reaction combined with spin-coating technology to form MWCNTs/CuS composite counter electrode (CE). The CuS adding amount is changed in different cycles to discuss its effect mechanism on the photoelectric properties of MWCNTs/CuS composite CE based quantum dot sensitized solar cells (QDSCs). The TiO2 photoanodes are prepared by the electrospinning technique with CdS and ZnS as co-sensitizer. QDSCs are assembled with photoanodes, the polysulfide electrolyte and abovementioned CEs. The CEs are characterized by X-ray diffraction, transmission electron microscope and energy dispersed X-ray detector, which verifies CuS nanocrystalline particles are attached to MWCNTs successfully. The photoelectric properties are analyzed by Nyquist, Tafel and J–V curves. The results show that the introduction of CuS nanocrystalline particles can promote reduction rate of polysulfide species and the short circuit current density (Jsc) to improve catalytic activity, leading to a higher power conversion efficiency (PCE). The MWCNTs based CE with deposition CuS in eight cycles exhibits the best photoelectric performance within all CE samples and the electrical conductivity of MWCNTs/8CuS CE is superior to that of Pt CE according to Nyquist and Tafel curve analysis. PCE of QDSCs with MWCNTs/8CuS CE is up to 5.186%, which is a little lower than that of Pt CE (5.250%), but it possesses a higher Jsc value (18.028?mA cm?2) than that of Pt CE (16.057?mA cm?2). The low-cost MWCNTs/CuS composite CE with simple preparation is more suitable than Pt CE for commercial application of QDSCs.
关键词： multi-wall carbon nanotubes,quantum dot sensitized solar cells,CuS nanocrystalline particles,photoelectric properties,counter electrode
更新于2025-09-10 09:29:36
-
Variation of the photoluminescence spectrum of InAs/GaAs heterostructures grown by ion-beam deposition
摘要： This work reports on an experimental investigation of the influence of vertical stacking of quantum dots, the thickness of GaAs potential barriers, and their isovalent doping with bismuth on the photoluminescence properties of InAs/GaAs heterostructures. The experimental samples were grown by ion-beam deposition. We showed that using three vertically stacked layers of InAs quantum dots separated by thin GaAs barrier layers was accompanied by a red-shift of the photoluminescence peak of InAs/GaAs heterostructures. An increase in the thickness of the GaAs barrier layers was accompanied by a blue shift of the photoluminescence peak. The effect of isovalent Bi doping of the GaAs barrier layers on the structural and optical properties of the InAs/GaAs heterostructures was investigated. It was found that the Bi content up to 4.96 atom % in GaAs decreases the density of InAs quantum dots from 1.53 × 1010 to 0.93 × 1010 cm?2. In addition, the average lateral size of the InAs quantum dots increased from 14 to 20 nm, due to an increase in the surface diffusion of In. It is shown that isovalent doping of GaAs potential barriers by bismuth was accompanied by a red-shift of the photoluminescence peak of InAs quantum dots of 121 meV.
关键词： photoluminescence,semiconductors,quantum dot,ion-beam deposition,nanoheterostructures,infrared photodetectors
更新于2025-09-10 09:29:36
-
[Springer Series in Optical Sciences] Fano Resonances in Optics and Microwaves Volume 219 (Physics and Applications) || Resonant-State Expansion of the Fano Peak in Open Quantum Systems
摘要： We describe the Fano asymmetry by expanding the transmission amplitude with respect to states with point spectra (discrete eigenstates), including not only bound states but also resonant states with complex eigenvalues. We ?rst introduce a novel complete set that spans the Hilbert space of the central part of an open quantum-dot system. This complete set contains all states of point spectra, but does not contain any states of continuous spectra. We thereby analytically expand the conductance of the dot in terms of all discrete states without any background integrals. This expansion implies that the resonant states produce the main contributions to the electron transmission. We then explain the Fano peak as an interference effect involving resonant states. We ?nd that there are three types of Fano asymmetry according to their origins: the interference between a resonant state and an anti-resonant state, that between a resonant state and a bound state, and that between two resonant states. We derive microscopic expressions of the Fano parameters that describe the three types of Fano asymmetry. We show that the last two types display the asymmetric energy dependence given by Fano, but the ?rst one shows a slightly different form.
关键词： transmission amplitude,Fano asymmetry,discrete eigenstates,resonant states,quantum-dot system
更新于2025-09-10 09:29:36
-
Investigation of nonlinear absorption and the electromagnetically induced transparency in a SMNP-SQD hybrid system by using the Mie theory
摘要： By using the Mie theory, nonlinear absorption coefficient and electromagnetically induced transparency (EIT) of a hybrid system consisting of GaAs spherical quantum dot (SQD) with ladder model and parabolic potential in the vicinity of a spherical metal nanoparticle (SMNP) are investigated. The density matrix equations in steady-state are solved and the third order susceptibility is obtained. Then, by using imaginary part of third order susceptibility, the nonlinear absorption coefficient are computed. Then, the effects of radii of SQD and SMNP, distance between SQD and SMNP and control laser frequency on nonlinear absorption coefficient and electromagnetically induced transparency (EIT) are investigated.
关键词： Metal nanoparticle,Mie theory,Spherical quantum dot,Electromagnetically induced transparency,Absorption coefficient
更新于2025-09-10 09:29:36
-
A facile synthesis of graphene nanoribbon-quantum dot hybrids and their application for composite electrolyte membrane in direct methanol fuel cells
摘要： In this work, we report the concept of synthesizing graphene nanoribbon-graphene quantum dot (GNR-GQD) hybrids with even grafting of GQD on GNR sheet in a facile single step process under ultrasonication in chlorosulfonic acid. Further, diazotization route is followed for the preparation of 4-benzenediazonium sulfonate precursor to sulfonate both GNR and GQD to form sulfonated graphene nanoribbons-sulfonated graphene quantum dots (sGNR-sGQD) nanohybrids. Synergistic and structure dependent effect of nanohybrids is seen via its dispersion in sulfonated poly(ether ether ketone) (sPEEK) to form nanocomposite membrane. sPEEK/sGNR-sGQD (1.5 wt. %) nanocomposite membrane shows remarkable direct methanol fuel cell (DMFC) performance compared to pristine sPEEK and Nafion 117 with 40 % increment in peak power density along with higher durability up to 100 h due to better physicochemical properties like water uptake, ion exchange capacity, proton conductivity, and reduced methanol crossover to suggest its potential which includes diverse membrane applications.
关键词： Graphene nanoribbon-graphene quantum dot hybrids,Nanohybrids,Nanocomposite membrane,Sulfonated poly(ether ether ketone),Direct methanol fuel cell
更新于2025-09-10 09:29:36
-
Effective GQD/AuNPs nanosensors for selectively bifunctional detection of lysine and cysteine under different photophysical properties
摘要： This work presented the development of the optical nanosensor based on AuNPs and GQDs which perform the efficiency dual optical sensor. Importantly, the AuNPs with GQDs was prepared by one-pot chemical reaction by using GQDs as an excellent bifunction of the reducing agent and stabilizer to obtain the disaggregated AuNPs/GQDs in red color property. Apart from its photophysical sensing ability, this hybrid material demonstrated the dual sensing of cysteine and lysine regarding to colorimetric and fluorometric techniques, respectively, in PBS solution pH 7.4. The presence of Cys in the AuNPs/GQDs solution rapidly lead to the color change from red to blue with concomitant of the red shift of the absorption band at 525 to 645 nm undergone the aggregation process. On the other hand, AuNPs/GQDs nanosensor in the presence of Lys performs the off-on fluorescence at 450 nm without color change in PBS solution pH 7.4. Interestingly, no interference of any amino acids towards Cys and Lys detection highlighted a high efficacy in selective sensing aspect. For sensing application, the detection limit of Cys and Lys was 5.88 μM and 16.14 μM, respectively, with an acceptable % recovery of 101–106 in real samples.
关键词： Graphene quantum dot,Gold nanoparticles,Aggregation,Lysine,Cysteine,Displacement
更新于2025-09-10 09:29:36