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Nutrient Levels in Brassicaceae Microgreens Increase Under Tailored Light-Emitting Diode Spectra
摘要： To increase the nutritional value and levels of essential minerals in vegetable food, microgreens are promising targets. The metabolic processes of microgreens can be managed with different cultivation techniques, which include manipulating the properties of light derived by light-emitting diodes (LEDs). In this study Brassicaceae microgreens (kohlrabi Brassica oleracea var. gongylodes, broccoli Brassica oleracea, and mizuna Brassica rapa var. Japonica) were cultivated under different light spectral quality, and the metabolic changes insoluble sugars (hexoses and sucrose), ascorbic acid, β-carotene, and contents of non-heme iron (Fe) and its connection with magnesium (Mg) or calcium (Ca) levels were monitored. Plants grew under the primary LED light spectrum (the combination of blue light at 447 nm, red at 638 and 665 nm, and far-red at 731 nm) or supplemented with LED green light at 520 nm, yellow at 595 nm, or orange at 622 nm. The photoperiod was 16 h, and a total PPFD of 300 μmol m-2 s-1 was maintained. Under supplemental yellow light at 595 nm, the content of soluble carbohydrates increased significantly in mizuna and broccoli. Under all supplemental light components, β-carotene accumulated in mizuna, and ascorbic acid accumulated significantly in kohlrabi. Under supplemental orange light at 622 nm, Fe, Mg, and Ca contents increased significantly in all microgreens. The accumulation of Fe was highly dependent on promoters and inhibitors of Fe absorption, as demonstrated by the very strong positive correlations between Fe and Ca and between Fe and Mg in kohlrabi and broccoli, and the strong negative correlations between Fe and β-carotene and between Fe and soluble carbohydrates in kohlrabi. Thus, the metabolic changes that occurred in treated microgreens led to increases in the contents of essential nutrients. Therefore, selected supplemental LED wavelengths can be used in the cultivation of Brassicaceae microgreens to preserve and increase the contents of specific nutritionally valuable metabolites.
关键词： microgreens,Brassicaceae,carbohydrates,β-carotene,ascorbic acid,mineral elements,light-emitting diodes
更新于2025-09-11 14:15:04
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Slot-Die-Printed Two-Dimensional ZrS <sub/>3</sub> Charge Transport Layer for Perovskite Light-Emitting Diodes
摘要： Liquid phase exfoliation of zirconium trisulfide (ZrS3) was used to produce stable and ready-to-use inks for solution processed semiconductor thin film deposition. Ribbon-like layered crystals of ZrS3 were produced by chemical vapor transport method and were then exfoliated in three different solvents: dimethyl formamide, ethanol and isopropyl alcohol. The resulting ZrS3 dispersions were compared for stability and the ability to form continuous films on top of perovskite layer in light-emitting diodes with ITO/PEDOT:PSS/MAPbBr3/2D-ZrS3/LiF/Al structure. Film deposition was performed by using either spray or slot-die coating methods. Slot-die coating route proved to produce better and more uniform films with respect to spray-coating. We found that 2D ZrS3 electron injection layer (EIL) stabilized the interface between the perovskite and LiF/Al cathode, reducing the turn-on voltage to 2.8 V and showing a luminance that does not degrade during voltage sweep. On the opposite, EIL-free devices show electroluminescence on the first voltage sweep that reduces almost to zero in the subsequent sweeps. Combining physical device simulation and Density Functional Theory calculation, we are able to explain these results in terms of lowering of electron injection barrier at the cathode.
关键词： perovskite light emitting diodes,slot-die printing,2D materials,exfoliation,transition metal trichalcogenides,ZrS3
更新于2025-09-11 14:15:04
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p-GaN/n-ZnO Nanorod/CsPbBr <sub/>3</sub> Quantum Dots Decorated with ZnO Nanoseeds for Light-Emitting Diodes
摘要： In this paper, we report the dual-wavelength green-light emission from zinc oxide (ZnO)-nanoseed-decorated p-GaN (gallium nitride)/n-ZnO nanorod/CsPbBr3 quantum dots (QDs) light-emitting diodes (LEDs). At the same time, the effect of ZnO nanoseeds on the p-GaN/n-ZnO nanorod/CsPbBr3 QDs LED performance is deeply studied. ZnO nanoseeds were fabricated by magnetron sputtering and the sol?gel method; then ZnO nanorods were obtained on GaN by hydrothermal treatment to form the p-GaN/n-ZnO nanorod heterojunction, and green CsPbBr3 QDs were further deposited on ZnO nanorod arrays to realize LEDs. The results show that magnetron-sputtering ZnO nanoseeds can induce regular vertical ZnO nanorod arrays, and the corresponding device presents a better electroluminescence (EL) performance. The X-ray diffraction, atomic force microscopy, and EL mechanisms indicate that the p-GaN/n-ZnO nanorod with magnetron-sputtering ZnO nanoseeds has a better crystalline interface. Our results indicate that the p-GaN/n-ZnO nanorod/CsPbBr3 QDs heterojunction structure can be served as dual-wavelength LEDs, and magnetron-sputtering ZnO nanoseeds can give rise to a better EL performance.
关键词： CsPbBr3 quantum dots,electroluminescence,ZnO nanoseeds,ZnO nanorods,light-emitting diodes
更新于2025-09-11 14:15:04
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Large-area near-infrared perovskite light-emitting diodes
摘要： The performance of perovskite light-emitting diodes (PeLEDs) has progressed rapidly in recent years, with electroluminescence efficiency now reaching 20%. However, devices, so far, have featured small areas and usually show notable variation in device-to-device performance. Here, we show that the origin of suboptimal device performance stems from inadequate hole injection, and that the use of a hole-transporting polymer with a shallower ionization potential can improve device charge balance, efficiency and reproducibility. Using an ITO/ZnO/PEIE/FAPbI3/poly-TPD/MoO3/Al device structure, we report a 799 nm near-infrared PeLED that operates with an external quantum efficiency (EQE) of 20.2%, at a current density of 57 mA cm?2 and a radiance of 57 W sr?1 m?2. The standard deviation in the device EQE is only 1.2%, demonstrating high reproducibility. Large-area devices measuring 900 mm2 operate with a high EQE of 12.1%, and are shown to suit medical applications such as subcutaneous deep-tissue illumination and heart rate monitoring.
关键词： near-infrared,hole injection,medical applications,perovskite light-emitting diodes,large-area
更新于2025-09-11 14:15:04
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High-Quality All-Inorganic Perovskite CsPbBr3 Quantum Dots Emitter Prepared by a Simple Purified Method and Applications of Light-Emitting Diodes
摘要： High-quality perovskite CsPbBr3 quantum dots (QDs-CsPbBr3) were prepared using the ultrasonic oscillation method, which is simple and provides variable yield according to requirements. The emission spectra over a large portion of the visible spectral region (450–650 nm) of QD-CsPbX3 (X = Cl, Br, and I) have tunable compositions that can be halide exchanged using the halide anion exchange technique and quantum size-effects. A strong peak with high intensity of (200) lattice plane of purified QDs-CsPbBr3 film is obtained, confirming the formation of an orthorhombic perovskite crystal structure of the Pnma space group. The photoluminescence of QDs-CsPbBr3 was characterized using a narrow line-width emission of 20 nm, with high quantum yields of up to 99.2%, and radioactive lifetime increasing to 26 ns. Finally, through the excellent advantages of QDs-CsPbBr3 mentioned above, purified perovskite QDs-CsPbBr3 as an active layer was utilized in perovskite quantum dot light-emitting diodes structure applications. As a result, the perovskite QDs-CsPbBr3 light-emitting diodes (LEDs) exhibits a turn-on voltage of 7 V and a maximum luminance of 5.1 cd/m2.
关键词： all-inorganic halide perovskite,perovskite CsPbBr3,quantum dot light-emitting diodes,quantum dots
更新于2025-09-11 14:15:04
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[IEEE 2019 IEEE Photonics Conference (IPC) - San Antonio, TX, USA (2019.9.29-2019.10.3)] 2019 IEEE Photonics Conference (IPC) - An Investigation on Stable and Continuous Operation of Hybrid Perovskite Quantum Dot Light Emitting Diodes
摘要： Two different package structures of hybrid perovskite quantum dots light emitting diodes were demonstrated with stable and continuous light emission. With boron nitride nanoparticles, the lifetime of device is expected to be thousands of hours.
关键词： Nanomaterials,Quantum-dot devices,Light-emitting diodes
更新于2025-09-11 14:15:04
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Blue-emitting dendritic molecule with dual functionality as host and dopant for solution-processed white OLEDs with red-emitting material
摘要： In this study, a three-armed dendritic molecule, 1,3,5-tris(10-(4-(2,6-diphenylpyrimidin-4-yl)phenyl)-9,9-diphenyl-9,10-dihydroacridin-2-yl)benzene (3PDPAc), was successfully synthesized and utilized as a blue dopant and its host of two-component white organic light-emitting diodes (WOLEDs). The high molecular weight of dendritic 3PDPAc showed an advantage in the production of rigid thin films with fine surface morphology after doping with red-emitting 7-(7,7-dimethyl-5,13,13-triphenyl-7,13-dihydro-5H-indeno[1,2-b]acridin-2-yl)benzo[c][1,2,5]thiadiazole-4-carbonitrile (IABTCN). Transient photoluminescence spectroscopy confirmed that 3PDPAc and IABTCN displayed conventional fluorescence behavior. Furthermore, it was possible to form a two-component emission layer with 3PDPAc and IABTCN when fabricating a WOLED. The WOLED device bearing 3PDPAc and IABTCN (99.5:0.5 wt. ratio) exhibited 3.80% of the maximum external quantum efficiency (EQE) and CIE coordinates of (0.33, 0.34) which indicates almost pure white emission. The chromaticity of white color emission could be tuned from cool white to warm white by varying the concentration of IABTCN. Moreover, the device with 3PDPAc and IABTCN has been observed to display emission stability because of the miscibility of the host and dopants. Thus, the dendritic structure of 3PDPAc is advantageous for fabrication of a rigid emitting layer.
关键词： White organic light-emitting diodes,Blend film,Solution-process,Dendritic molecule
更新于2025-09-11 14:15:04
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Sonochemical Synthesis of Carbon Dots/Lanthanoid MOFs Hybrids for White Light-Emitting Diodes with High Color Rendering
摘要： Although lanthanoid metal-organic frameworks (Ln-MOFs) have been widely developed for white light-emitting diodes (WLEDs), the color rendering index (CRI) values are still lower than 80. To overcome this limitation, a series of carbon dots/Ln-MOFs hybrids namely CDs-2@Ln-MOF, CDs-3@Ln-MOF and CDs-4@Ln-MOF containing blue emitting CDs and yellow emitting bimetallic [(Eu1.22Tb0.78(1,4-phda)3(H2O)](H2O)2 were prepared via sonication at room temperature to restrict the self-quenching of CDs in composite materials. The as-synthesized composite materials were investigated by FT-IR, PXRD, TEM, SEM and photoluminescence. The luminescent color of the materials can be adjusted by varying the amount of CDs and excitation wavelengths. The resulting CDs-3@Ln-MOF achieved excellent CRI up to 93 with the ideal CIE coordinate (0.334, 0.334) and appropriate correlated color temperature, CCT (5443 K). In addition, the tunable multi-colored luminescence based on single and bimetallic EuxTb2-x(1,4-phda)3(H2O)](H2O)2; x = 0, 0.73, 1.22, 1.57, 1.94 and 2 were applied as the luminescent security inks for anti-counterfeiting application through encoding/decoding and rewritable data.
关键词： anti-counterfeiting,luminescence material,white light-emitting diodes,metal-organic frameworks,carbon dots
更新于2025-09-11 14:15:04
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Methylammonium-Mediated Crystallization of Cesium-Based 2D/3D Perovskite toward High-Efficiency Light-Emitting Diodes
摘要： 2D/3D perovskites have been successfully applied to high-efficiency light-emitting diodes (LEDs) due to their large exciton binding energy (Eb) caused by the quantum and dielectric confinements. Thermal annealing and antisolvent treatments are usually executed in order to promote the crystallization and film quality of perovskites, which add complexity to the device fabrication process. Here, the Cesium-based 2D/3D perovskite was prepared by introducing an ammonium halide benzamidine hydrochloride (BMCl) as the additive. By further introducing an appropriate amount of MABr and PbBr2, BM2(Cs1-xMAxPbBr3)n-1PbBr4 crystals can be formed rapidly without any additional treatments, whilst inhibiting the formation of unfavorable Cs4PbBr6 phase. The optimized 2D/3D perovskite based LEDs achieved a maximum luminance of 12367 Cd/m2, current efficiency of 17.4 Cd/A, and EQE of 5.2%. Our results suggest that appropriate perovskite crystallization can be achieved at room temperature by the regulation of precursor solution, making the perovskite crystallization process easier to control with reduced processing complexity.
关键词： CsPbBr3,light-emitting diodes,perovskite,fast crystallization,2D/3D
更新于2025-09-11 14:15:04
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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