- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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<i>(Invited)</i> Mid-Infrared Colloidal Quantum Dot Based Nanoelectronics and Nano-Optoelectronics
摘要： Electronic and optoelectronic devices fabricated from colloidal quantum dots (CQDs) provide a promising path toward realizing low-cost devices with greatly simplified device fabrication procedure, owing to their solution-processability. The impact that CQD technology would bring is expected to be significant, especially in the mid-infrared application areas, which is currently dominated by epitaxial semiconductor technologies. In this work, we introduce a new generation of infrared CQDs, namely Ag2Se CQDs, which has been recently uncovered to show distinct optical absorption in the mid-infrared. We report on the fabrication of solution-processed photoconductive photodetectors and discuss our analyses on the electronic and optoelectronic characteristics of our devices. We also demonstrate the feasibility of mid-infrared photodetection with a measured peak responsivity of 0.16 mA/W at 4 μm under room temperature operation.
关键词： Ag2Se,solution-processability,photodetectors,mid-infrared,colloidal quantum dots
更新于2025-09-19 17:13:59
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23.4: <i>Invited Paper:</i> The Longevity Study for Hybrid Colloidal Quantum Dot Optoelectronic Devices
摘要： The nano-scale size of colloidal quantum dots provide unique properties, such as strong luminescent efficiency, wavelength tunable emission, and narrow linewidth etc., which are desirable for high quality display devices. However, the reliability of these nanoparticles is always the center of attention when the commercialization issue is discussed. In this paper, we will review our latest result on the hybrid package method that can dramatically these magnificent optoelectronic materials . lifetime of improve the
关键词： reliability tests,Light emitting diodes,colloidal quantum dots,solar cells
更新于2025-09-19 17:13:59
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Quantum Dot-Plasmon Lasing with Controlled Polarization Patterns
摘要： The tailored spatial polarization of coherent light beams is important for applications ranging from microscopy to biophysics to quantum optics. Miniaturized light sources are needed for integrated, on-chip photonic devices with desired vector beams; however, this issue is unresolved because most lasers rely on bulky optical elements to achieve such polarization control. Here, we report on quantum dot-plasmon lasers with engineered polarization patterns controllable by near-field coupling of colloidal quantum dots to metal nanoparticles. Conformal coating of CdSe?CdS core?shell quantum dot films on Ag nanoparticle lattices enables the formation of hybrid waveguide-surface lattice resonance (W-SLR) modes. The sidebands of these hybrid modes at nonzero wavevectors facilitate directional lasing emission with either radial or azimuthal polarization depending on the thickness of the quantum dot film.
关键词： nanolaser,band structure engineering,radially and azimuthally polarization states,surface lattice resonances,colloidal quantum dots,lattice plasmons,waveguide
更新于2025-09-19 17:13:59
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Nonradiative Energy Transfer in a??Colloidal Quantum Dot Nanoclustera??Dyea?? Hybrid Nanostructures: Computer Experiment
摘要： A computer model of nonradiative electronic excitation energy transfer from nanoclusters of colloidal quantum dots of cadmium selenide to the meso-tetra(3-pyridyl)porphyrin molecule in hybrid nanostructures nanocluster–dye has been constructed and analyzed. The model uses the experimental luminescence and absorption spectra of quantum dots and the dye, takes into account heterogeneity of the properties of quantum dots in nanoclusters and the different location of the dye in the hybrid structure. It has been shown that, in the ideal case, due to such energy transfer, the intensity of the luminescent signal of the dye can be increased by five orders of magnitude. However, this value is significantly reduced due to nonluminescent particles, the presence of a protective ligand shell, a large size distribution of the particles, and the non-optimal geometric structure of the hybrid system.
关键词： porphyrin dye,colloidal quantum dots,F?rster resonance energy transfer,hybrid systems,cadmium selenide,computer simulation
更新于2025-09-19 17:13:59
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Improving indistinguishability of single photons from colloidal quantum dots using nanocavities
摘要： Colloidal quantum dots have garnered active research interest as quantum emitters due to their robust synthesis process and straightforward integration with nanophotonic platforms. However, obtaining indistinguishable photons from the colloidal quantum dots at room temperature is fundamentally challenging because they suffer from an extremely large dephasing rate. Here we propose an experimentally feasible method of obtaining indistinguishable single photons from an incoherently pumped solution-processed colloidal quantum dot coupled to a system of nanocavities. We show that by coupling a colloidal quantum dot to a pair of silicon nitride cavities, we can obtain comparable performance of a single photon source from colloidal quantum dots as other leading quantum emitters like defect centers and self-assembled quantum dots.
关键词： Colloidal quantum dots,Nanocavities,Indistinguishable single photon source
更新于2025-09-16 10:30:52
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Spatial Collection in Colloidal Quantum Dot Solar Cells
摘要： In thin-film photovoltaic (PV) research and development, it is of interest to determine where the chief losses are occurring within the active layer. Herein, a method is developed and presented by which the spatial distribution of charge collection, operando, is ascertained, and its application in colloidal quantum dot (CQD) solar cells is demonstrated at a wide range of relevant bias conditions. A systematic computational method that relies only on knowledge of measured optical parameters and bias-dependent external quantum efficiency spectra is implemented. It is found that, in CQD PV devices, the region near the thiol-treated hole-transport layer suffers from low collection efficiency, as a result of bad band alignment at this interface. The active layer is not fully depleted at short-circuit conditions, and this accounts for the limited short-circuit current of these CQD solar cells. The high collection efficiency outside of the depleted region agrees with a diffusion length on the order of hundreds of nanometers. The method provides a quantitative tool to study the operating principles and the physical origins of losses in CQD solar cells, and can be deployed in thin-film solar cell device architectures based on perovskites, organics, CQDs, and combinations of these materials.
关键词： colloidal quantum dots,Gaussian regularization least-squares,spatial collection efficiency,photovoltaics
更新于2025-09-16 10:30:52
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Solution-processed P3HT:PbS based NIR Photodetector with FET Configuration
摘要： A near-infrared (NIR) solution-processed photodetector based on a mixture of PbS colloidal quantum dots (CQDs) and Poly(3-hexylthiophene) (P3HT) was presented. In a reverse field-effect transistor (FET) device configuration Au(S,D)/P3HT:PbS/PMMA/Al(G), uniform-sized and well-dispersed PbS CQDs were employed as NIR absorbing materials in the active layer. Meanwhile, the poly(methyl methacrylate) (PMMA) dielectric layer could be seen as an encapsulation to enhance the device stability. Herein, High “on/off” current ratio (Ion/Ioff) of 104 was obtained in dark, and the maximum photosensitivity (P) of 947 was gotten under 200 mW/cm2 980 nm illumination. When the irradiance reduced to 0.1 mW/cm2, the responsivity (R) and detectivity (D?) of the NIR photodetector reached 9.4 mA/W and 2.5×1011 Jones, respectively. Therefore, the P3HT:PbS hybrid FET-based NIR photodetector had shown both relatively high electrical and detecting performance, which provided an experimental foundation and method for the next fabrication of medical infrared detectors and sensors.
关键词： PbS colloidal quantum dots (CQDs),Near-infrared (NIR) photodetector,Poly(3-hexylthiophene) (P3HT),Field-effect transistor (FET)
更新于2025-09-16 10:30:52
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Observation of a phonon bottleneck in copper-doped colloidal quantum dots
摘要： Hot electrons can dramatically improve the efficiency of solar cells and sensitize energetically-demanding photochemical reactions. Efficient hot electron devices have been hindered by sub-picosecond intraband cooling of hot electrons in typical semiconductors via electron-phonon scattering. Semiconductor quantum dots were predicted to exhibit a "phonon bottleneck" for hot electron relaxation as their quantum-confined electrons would couple very inefficiently to phonons. However, typical cadmium selenide dots still exhibit sub-picosecond hot electron cooling, bypassing the phonon bottleneck possibly via an Auger-like process whereby the excessive energy of the hot electron is transferred to the hole. Here we demonstrate this cooling mechanism can be suppressed in copper-doped cadmium selenide colloidal quantum dots due to femtosecond hole capturing by copper-dopants. As a result, we observe a lifetime of ~8.6 picosecond for 1Pe hot electrons which is more than 30-fold longer than that in same-sized, undoped dots (~0.25 picosecond).
关键词： phonon bottleneck,electron-phonon scattering,hot electrons,colloidal quantum dots,copper-doped
更新于2025-09-16 10:30:52
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Illustrating the Shell Thickness Dependence in Alloyed Core/Shell Quantum Dot based Light-Emitting Diodes by Impedance Spectroscopy
摘要： Colloidal quantum dots (QDs) are talented materials and have been extensively investigated in the field of photonics and optoelectronics due to their size-dependent optical properties. The core/shell structure of QDs with wide bandgap shell has been adopted for obtaining stable emission and high PL quantum efficiency. However, when employed in active devices such as light-emitting diodes (LEDs), the thick shell structure of QDs may impede the transportation of carriers thus deteriorate the device performance. In this work, the effect of shell thickness of CdSe/ZnS QDs on device performance is systematically studied through impedance spectroscopy (IS) by constructing the electron-only symmetric device architecture. It is found that the evolution of capacitance in the symmetric device under applied voltage reflects the charge accumulation within the device and predicts the LED performance. The lowest capacitance is evaluated in the symmetric device containing QDs with a medium shell size of 2.1 nm, showing improved performance in LED with the highest luminance and current efficiency (CE) of 26370 cd/m2 and 8.3 cd/A respectively.
关键词： impedance spectroscopy,light-emitting diodes,charge accumulation,shell thickness,Colloidal quantum dots
更新于2025-09-16 10:30:52
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Study of Electrophotophysical Characteristics of IR Photodetectors Based on PbS Colloidal Quantum Dots
摘要： The electrophotophysical characteristics of laboratory samples of IR photodetectors obtained by dip coating of PbS colloidal quantum dots with the subsequent exchange of oleic acid molecules that compose their ligand shell by S2? ions have been studied.
关键词： thin layers,electrophysical characteristics of layers,spectral and luminescent properties,dip-coating method,near infrared region,PbS colloidal quantum dots,ligand exchange,IR photodetectors
更新于2025-09-16 10:30:52