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Electron transfer mediated by iron carbonyl clusters enhance lighta??driven hydrogen evolution in water by quantum dots
摘要： Photocatalytic water splitting has become a promising strategy for converting solar energy into clean and carbon-neutral solar fuels via a low-cost and environmentally benign way. Hydrogen gas is such a potential solar fuel/energy carrier. In a classical artificial photosynthetic system, a photosensitizer is generally associated with a co-catalyst to convert photogenerated charge into (a) chemical bond(s). In the present study, assemblies consisting of CdSe quantum dots that are coupled with one of two [Fe2S2(CO)6] or [Fe3Te2(CO)9], using an interface-directed approach, have been tested as catalytic systems for hydrogen production in aqueous solution/organic solution. In the presence of ascorbic acid as a sacrificial electron donor and proton source, these assemblies exhibit enhanced activities for the rate of hydrogen production under visible light irradiation for 8 hrs in aqueous solution at pH 4.0 with up to 110 μmol of H2 per mg of assembly, almost 8.5 times that of pure CdSe quantum dots under the same conditions. Transient absorption and time-resolved photoluminescence spectroscopies have been used to investigate the charge carrier transfer dynamics in the quantum dot/iron carbonyl cluster assemblies. The spectroscopic results indicate that effective electron transfer from the molecular iron complex to the valence band of the excited CdSe quantum dots to the significantly inhibits the recombination of photogenerated charge carriers, boosting the photocatalytic activity for hydrogen generation; i.e. the iron clusters function as effective intermediaries for electron transfer from the sacrificial electron donor to the valence band of the quantum dots.
关键词： iron carbonyl cluster,quantum dot,electron transfer,proton reduction
更新于2025-09-19 17:13:59
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Entanglement of two distant quantum dots with the flip-flop interaction coupled to plasmonic waveguide
摘要： The entanglement of two distant quantum dots coupled to metallic waveguide has been investigated theoretically in the presence of the flip-flop interaction with the analytic solutions of eigenvalue equations of the system. High entanglement of two quantum dots could be achieved by adjusting the direct-coupling strength of two quantum dots, the coupling strength of quantum dots with surface plasmon along metallic waveguide, the group velocity of surface plasmon and detuning. The discussed system with the flip-flop interaction provides us with a rich way to realize the quantum device for quantum information processing, such as quantum communication and quantum computation.
关键词： surface plasmon,Quantum dot,entanglement,waveguide
更新于2025-09-19 17:13:59
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Low Temperature Processed Highly Efficient Hole-Transport-Layer Free Carbon-based Planar Perovskite Solar Cells with SnO2 Quantum Dot Electron-Transport-Layer
摘要： The use of expensive hole transport layer (HTL) and back contact along with the stability issue of perovskite solar cells have been a detrimental factor when it comes to commercialization of the technology. In addition, high-temperature and long annealing time processed electron transport layers (ETLs, e.g., TiO2) prevents the flexible solar cell application in most polymer substrate. Herein, we opted for HTL-free carbon electrodes owing to their low-cost production and superior stability in air, compared to their noble metal counterparts. In this work, we fabricate planar perovskite solar cells using low-temperature solution processed SnO2 quantum dots (QDs) as ETL, which offers significant advantages over high temperature processed ETLs due to its excellent electron extraction and hole blocking ability. In addition, by integrating a low cost and stable carbon electrode, an impressive energy conversion efficiency of 13.64% with a device architecture glass/In doped SnO2/QD-SnO2/Perovskite/Carbon under 1 sun illumination at ambient conditions have been achieved. This work paves the way to achieve fully low-temperature processed printable perovskite solar cells (PSCs) at an affordable cost by integrating the QD SnO2 ETL and Carbon electrode.
关键词： low-temperature process,planar perovskite solar cells,hole transport layer free,carbon electrode,SnO2 Quantum Dot
更新于2025-09-19 17:13:59
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Stacked Encapsulation Structure for Discretely Distributed Quantum Dot Array
摘要： The performances of quantum-dot (QD) based photoluminescent devices are highly restricted by the application environment, especially the moisture and oxygen. However, current external encapsulation structures are not applicable to the devices with discrete QD distribution, especially for some rough profiles. To address this issue, an encapsulation method for discretely distributed quantum-dot arrays (DQDA) is proposed for liquid crystal display (LCD) backlight applications, in which the DQDA can be well fabricated by printing the QD slurry onto a light guiding substrate (LGS), and then covered with a thin UV glue layer and a barrier film. By specially optimizing the UV glue and barrier film, this ultra-thin encapsulation structure cannot only improve the surface defects of the QD morphology without affecting the original light path and the output optical performance, but also significantly suppress the fluorescence decay and isolate moisture and oxygen by almost 100 times compared with unencapsulated one. The water vapor transmission rate (WVTR) was measured to be 1.29 × 10?4 g/m2/day after fabricated the stacked encapsulation structure. After a long period of aging test, the encapsulated sample kept its luminance for 1000 hours. This method also has potential to widely used for discrete structures in other device applications due to its easy fabrication process, high reliability, and low manufacturing costs.
关键词： encapsulation,oxygen,stacked structure,moisture,Quantum-dot array
更新于2025-09-19 17:13:59
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Sensitive detection of influenza a virus based on a CdSe/CdS/ZnS quantum dot-linked rapid fluorescent immunochromatographic test
摘要： Prevention is the most effective management strategy for influenza A infection in humans. In this study, we developed a CdSe/CdS/ZnS quantum dot (QD) fluorescent dye for rapid and sensitive detection of two common subtypes (H1N1 and H3N2) of influenza A virus, and examined its utility. CdSe/CdS/ZnS QD was conjugated with antibody (Ab) after conjugation with latex, making QD conjugate of QD+Latex+Ab. A stable photoluminescence of QD conjugate and advantage of CdSe/CdS/ZnS QD used was characterized in this study. The performance of a rapid fluorescent immunochromatographic test (FICT) employing QD conjugate (QD-FICT) in detecting influenza A/H1N1 was 8-fold and 64-fold higher than that of a europium nanoparticle-based FICT and a rapid diagnostic test (RDT; Standard Diagnostics BIOLINE Influenza A/B), respectively. For influenza A/H3N2, QD-FICT showed 8-fold and 128-fold higher performance than europium nanoparticle-based FICT and RDT, respectively. In clinical evaluations, QD-FICT showed 93.75% clinical sensitivity [45/48; 95% confidence interval (95% CI): 82.80-98.69], 100% clinical specificity (117/117; 95% CI: 96.90-100.00), and strong correlation (kappa; 0.98) with rRT-PCR (20 ≤ Ct ≤ 40). Europium nanoparticle-linked FICT showed 79.17% clinical sensitivity (38/48; 95% CI: 65.01-89.53) and 100% clinical specificity (117/117; 95% CI: 96.90-100.00), whereas RDT showed 77.08% sensitivity (37/48; 95% CI: 62.69-87.97), 100% specificity (117/117; 95% CI: 96.90-100.00), and reasonably good correlation with rRT-PCR (kappa; 0.93). Water-soluble QDs can therefore be used as an effective material for developing fluorescent diagnostic systems for rapid detection of human influenza A virus in clinical specimens.
关键词： Rapid Fluorescent Immunochromatographic Test,Influenza A Virus,Quantum Dot Fluorescent Dye
更新于2025-09-19 17:13:59
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Optimization of a spectrally tunable daylight simulator using four quantum dot light‐emitting diodes for visual appraisal of color
摘要： An optimization model for luminous efficacy of a spectrally tunable light-emitting diode (LED) daylight simulator under constraint of metamerism index was developed. It was first reported that the optimal spectrally tunable LED daylight simulator of AA grade for D50, D55, D65, and D75 standard illuminants could consist of two quantum dot-integrated LEDs (QDLEDs) with the ultraviolet chip and two other QDLEDs with the blue chip. The optimized spectral parameters of each QDLED, as well as photometric and colorimetric performances of D50, D55, D65, and D75 daylight simulators, were obtained by maximizing luminous efficacy under the metamerism index for both a visible and ultraviolet range less than 0.25. The limit luminous efficacies of four daylight simulators using four QDLEDs under the ideal case will reach 181 lm/W to 205 lm/luminous efficacies with a radiant efficiency of both the ultraviolet and blue chips of 60%, as well as a quantum efficiency of a quantum dots layer of 90%, will reach 100 lm/W to 112 lm/W.
关键词： daylight simulator,metamerism index,optimization,luminous efficacy,quantum dot LED
更新于2025-09-19 17:13:59
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Binding energies and photoionization cross-sections of donor impurities in GaN/AlxGa1a??xN spherical quantum dot under hydrostatic pressure
摘要： In this paper, the binding energy and photoionization cross-section of donor impurity state in GaN/AlxGa1?xN quantum dot structure are studied theoretically by using variational method. The variation of binding energy and photoionization cross-section with core and shell sizes at di?erent impurity locations under hydrostatic pressure is calculated numerically. The results show that the binding energy decreases monotonously with the core size at di?erent impurity locations for GaN/AlxGa1?xN core/shell quantum dot. In contrast, for the inverted core/shell quantum dot, the binding energy exhibits di?erent trends with the increase of core size at di?erent impurity locations. But the binding energy decreases monotonically with the shell size for both of them. Moreover, when the photon energy is approximately equal to the donor binding energy, the peak of the photoionization cross-section appears. There will be di?erent peak shifts under di?erent conditions, and its peak intensity increases with the increase of core and shell sizes. When the hydrostatic pressure is applied, the binding energy and the peak strength of the photoionization cross-section increase with the increase of the pressure.
关键词： hydrostatic pressure,Spherical quantum dot,binding energy,photoionization cross-section
更新于2025-09-19 17:13:59
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Strain tunable quantum dot based non-classical photon sources
摘要： Semiconductor quantum dots are leading candidates for the on-demand generation of single photons and entangled photon pairs. High photon quality and indistinguishability of photons from different sources are critical for quantum information applications. The inability to grow perfectly identical quantum dots with ideal optical properties necessitates the application of post-growth tuning techniques via e.g. temperature, electric, magnetic or strain fields. In this review, we summarize the state-of-the-art and highlight the advantages of strain tunable non-classical photon sources based on epitaxial quantum dots. Using piezoelectric crystals like PMN-PT, the wavelength of single photons and entangled photon pairs emitted by InGaAs/GaAs quantum dots can be tuned reversibly. Combining with quantum light-emitting diodes simultaneously allows for electrical triggering and the tuning of wavelength or exciton fine structure. Emission from light hole exciton can be tuned, and quantum dot containing nanostructure such as nanowires have been piezo-integrated. To ensure the indistinguishability of photons from distant emitters, the wavelength drift caused by piezo creep can be compensated by frequency feedback, which is verified by two-photon interference with photons from two stabilized sources. Therefore, strain tuning proves to be a flexible and reliable tool for the development of scalable quantum dots-based non-classical photon sources.
关键词： quantum dot,on-chip,piezoelectric crystal,entangled photons,fine structure splitting,strain tuning
更新于2025-09-19 17:13:59
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P‐9.13: A Vertical Type Photodetector Based on All‐inorganic Perovskite Quantum Dots
摘要： In this work, the vertical type photodetector (PD) based on CsPbBr3 QDs with a structure of indium tin oxide (ITO)/ zinc oxide (ZnO)/ CsPbBr3 QDs/ Au is reported. In this device, the ZnO layer acts as a buffer layer, which can improve the uniformity and surface coverage of the CsPbBr3 QDs film to eliminate the current-leakage. As a result, the on/ off ratio, D* and rise time (decay time) of CsPbBr3/ZnO hybrid PD is measured to be 2.2x104, 1.06x1011 and 62ms (82ms) under low reverse bias. This work inspires the development of vertical type photodetectors based on the all-inorganic perovskite quantum dots.
关键词： ZnO,All-inorganic perovskite quantum dot,Vertical type photodetector
更新于2025-09-19 17:13:59
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Efficiency Enhancement of Perovskite CsPbBr <sub/>3</sub> Quantum Dot Light-emitting Diodes by Doped Hole Transport Layer
摘要： Balanced charge injection is essential to high-performance Perovskite CsPbBr3 quantum dot-based light-emitting diodes (QLEDs). However, low mobility of hole-transport materials (HTMs) severely restrict improving performance of QLEDs. Herein, we provide a novel HTMs to improve the highest occupied molecular orbital (HOMO) energy level structure and carrier mobility by doping poly (9-vinlycarbazole) (PVK) and poly [N, N′-bis(4-butylphenyl)-N, N′-bis(phenyl) benzi-dine] (poly-TPD). We also introduce poly (methyl methacrylate) (PMMA) as electron block layer to further achieve charge injection balance. Finally, an enhanced external quantum efficiency (EQE) of 0.53% and 414.83 cd/m2 was obtained. Compared with the untreated QLED, this result has been 8-fold enhanced, provides a new approach to attain better performance.
关键词： Quantum Dot Light-emitting Diodes,Efficiency Enhancement,Perovskite CsPbBr3,Hole Transport Layer
更新于2025-09-19 17:13:59