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ZnO@graphene QDs with tuned surface functionalities formed on eco-friendly keratin nanofiber textile for transparent and flexible ultraviolet photodetectors
摘要： We demonstrate the ZnO@graphene core@shell quantum dot (ZGQDs) fabricated by selectively engineering of oxygenated functional groups on the graphene shells with eco-friendly keratin textile for transparent and flexible UV photodetector devices. The ZGQDs with the octylamine (ZGQDs-OA) and the graphene sheet were employed as an active material and an electron transport channel. The functional groups on the surrounding graphene shell in ZGQDs were passivated by the OA, resulting in a good absorbance in UV light and excellent carrier transport properties. The passivation of the functional groups on the graphene shell by OA drastically enhanced the photocurrent. Optical transmittance of the ZGQDs-OA/graphene sheets/PMMA/keratin nanofiber textile composites structures was approximately 77 % at the visible spectrum range. Current–voltage (I-V) and current–time (I-t) measurements on the UV photodetector under illumination state in bending condition exhibited the excellent ON/OFF switching states and stability. The photosensitivity and responsivity of the photodetector with ZGQDs-OA were found to be around 13.10 and 68.64 μAmW-1, respectively, which is much higher than that without the passivation. The improved performance of the photodetector with ZGQDs-OA could be attributed to the efficient electron transport to the electrode by the passivation of the graphene on ZnO QDs.
关键词： ZnO@graphene QDs,flexible device,photodetector,Eco-friendly,Textile
更新于2025-09-12 10:27:22
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Size-Programmed Synthesis of PbSe Quantum Dots via Secondary Phosphine Chalcogenides
摘要： In the most common syntheses of colloidal nanocrystal quantum dots (QDs) the size of the particle increases monotonically with reaction time. We have discovered a PbSe QD synthesis whereby size can be easily controlled by varying the side-chains of a secondary phosphine selenide precursor. The reaction runs to completion, and thus a desired QD diameter can be achieved by simply selecting an appropriate secondary phosphine. Quenching of the reaction to select a desired QD size is not required. For different secondary phosphine selenides, measurements of the precursor conversion rate show a direct relationship with final QD size, while P=Se bond strength calculations show an unexpected inverse relationship between QD size and P=Se bond strength. Finally, it is also demonstrated that secondary phosphine selenide precursors can provide an effective route for IV-VI QD syntheses on the large scale.
关键词： colloidal synthesis,size control,IV-VI QDs,secondary phosphine selenide,PbSe quantum dots
更新于2025-09-12 10:27:22
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Ultraefficient Green LEDs Using Quantum Dots in Liquid Matrix
摘要： Green spectral range, which has the highest human eye sensitivity, is one of the most fundamental colors in lighting and display. Quantum dots (QDs) offer exceptional optical properties including high quantum yield (QY), strong absorption, and narrow emission linewidths for efficient green-emitting diodes. In this article, we demonstrated QD-based light-emitting diodes (QD-LEDs) that operate at a luminous efficiency (LE) level of 95 lumens per electrical watt, the luminous efficacy of optical radiation of 409 lumens per optical watt, and external quantum efficiency (EQE) of 23.3% in the green spectral region. For that, we synthesized 1-octanethiol-capped CdSe/ZnS QDs with an absolute QY of 91% and integrated them in a liquid matrix that allows conservation of the QD efficiency in device architecture. Our simulations were in agreement with the performance of the fabricated QD-LEDs, and they showed that the QD-LEDs can be further improved to reach LE levels over 250 lm/W.
关键词： light-emitting diodes (LEDs),luminous efficiency (LE),liquid-state integration,quantum dots (QDs),External quantum efficiency (EQE)
更新于2025-09-12 10:27:22
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CdSe/ZnS Quantum-Dot Light-Emitting Diodes With Spiro-OMeTAD as Buffer Layer
摘要： We report a high-ef?cient green CdSe/ZnS quantum-dot light-emitting diode (QLED) using 2,2’,7,7’-Tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9’-Spirobi?uorene (Spiro-OMeTAD) as an electron buffer layer. The high lowest unoccupied molecular orbital level of Spiro-OMeTAD suppresses the electron transfer and promotes the charge balance. The external quantum ef?ciency (EQE) of the green QLED device is increased by 1.93 times to 14.65%, and the brightness is increased by 1.37 times to 55 760 cd/m2. The results show that the Spiro-OMeTAD layer can effectively prevent excessive electron injection into QDs, and balance the combination of electron and hole carriers.
关键词： charge balance,light-emitting diodes,quantum dots (QDs),Buffer layer
更新于2025-09-12 10:27:22
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Development of Ratiometric Fluorescence Sensors Based on CdSe/ZnS Quantum Dots for the Detection of Hydrogen Peroxide
摘要： In this study, carboxyl group functionalized-CdSe/ZnS quantum dots (QDs) and aminofluorescein (AF)-encapsulated polymer particles were synthesized and immobilized to a sol–gel mixture of glycidoxypropyl trimethoxysilane (GPTMS) and aminopropyl trimethoxysilane (APTMS) for the fabrication of a hydrogen peroxide-sensing membrane. CdSe/ZnS QDs were used for the redox reaction of hydrogen peroxide (H2O2) via a reductive pathway by transferring electrons to the acceptor that led to fluorescence quenching of QDs, while AF was used as a reference dye. Herein, the ratiometric fluorescence intensity of CdSe/ZnS QDs and AF was proportional to the concentration of hydrogen peroxide. The fluorescence membrane (i.e., QD–AF membrane) could detect hydrogen peroxide in linear detection ranges from 0.1 to 1.0 mM with a detection limit (LOD) of 0.016 mM and from 1.0 to 10 mM with an LOD of 0.058 mM. The sensitivity of the QD–AF membrane was increased by immobilizing horseradish peroxidase (HRP) over the surface of the QD–AF membrane (i.e., HRP–QD–AF membrane). The HRP–QD–AF membrane had an LOD of 0.011 mM for 0.1–1 mM H2O2 and an LOD of 0.068 mM for 1–10 mM H2O2. It showed higher sensitivity than the QD–AF membrane only, although both membranes had good selectivity. The HRP–QD–AF membrane could be applied to determine the concentration of hydrogen peroxide in wastewater, while the QD–AF membrane could be employed for the detection of α-ketobutyrate.
关键词： ratiometric fluorescence QD membrane,CdSe/ZnS QDs,hydrogen peroxide,α-ketobutyrate,redox reaction
更新于2025-09-12 10:27:22
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A Layered Photo-Anode Prepared Using TiO <sub/>2</sub> ?Nanocrystals with Different Sizes for Enhanced Light-Trapping in Quantum Dots-Sensitized Solar Cells
摘要： Using TiO2 nanocrystals (NCs) with diameters of 20 nm (T20), 40 nm (T40) and 60 nm (T60) as starting materials, three TiO2 photo-anodes were constructed on FTO glass. Meanwhile, a triple-layered photo-anode was prepared by depositing the T20, the T40, and the T60 layer by layer on FTO glass (T60/T40/T20/FTO/glass). These four kinds of photo-anodes were sensitized with CdZn0.02S0.08Se0.92 QDs by successive ionic layer adsorption and reaction (SILAR). Based on these photo-anodes, four quantum dot-sensitized solar cells (QDSSCs) were ?nally obtained. The results indicated that the highest ef?ciency of 3.95% was obtained in the QDSSC with the triple-layered photo-anode. The short-circuit photocurrent density (Jsc) of the QDSSC with the triple-layered photo-anode was 1.25, 1.21 and 1.13-fold higher than that of the QDSSCs with T20-, T40- and T60-based photo-anode, respectively. Moreover, with the increase of the average size of the TiO2 NCs from 20 to 60 nm, the Jsc increased from 13.8 to 15.24 mA·cm?2. The optical properties, crystal structure and morphologies of the bare TiO2 ?lms and the CdZn0.02S0.08Se0.92 sensitized TiO2 photo-anodes were characterized by UV-Vis spectroscopy, XRD and SEM. The incident photon-to-electron conversion ef?ciency, the open circuit voltage decay and the electrochemical impedance spectroscopy of the QDSSCs were measured and discussed, so as to clarify the underlying mechanism of the property enhancement.
关键词： quantum dots-sensitized solar cells,TiO2 nanocrystals,light-trapping,CdZn0.02S0.08Se0.92 QDs,photo-anode
更新于2025-09-11 14:15:04
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The Preparation and Up-Conversion Properties of Full Spectrum CsPbX3 (X = Cl, Br, I) Quantum Dots Glasses
摘要： All-inorganic perovskite (CsPbX3) quantum dots (QDs) have achieved unprecedented success in various applications due to their outstanding performance. Nevertheless, the inherent instability of these QDs severely limits their practical applications. Here, ultra-stable full visible spectrum CsPbX3 (X = Cl, Br, I) QDs glasses were prepared successfully. For the first time, CsPbX3 QDs glasses were observed full spectrum tunable up-conversion (UC) emission (420–711 nm) with the excitation of 800 nm femtosecond (fs) laser. Importantly, the two-photon absorption properties, the exciton binding energy and the UC full width at half maximum (FWHM) of the CsPbCl1.5Br1.5 (blue), CsPbBr3 (green), and CsPbBr1.5I1.5 (red) QDs glasses were studied in depth. Furthermore, CsPbCl1.5Br1.5 was observed to have the highest exciton binding energy (~87.5 meV), allowing the CsPbCl1.5Br1.5 QDs glass to act as a good optical gain material that could more easily achieve amplified spontaneous emission (ASE).
关键词： CsPbX3 perovskite,full spectrum,two-photon,QDs glass,UC emission
更新于2025-09-11 14:15:04
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Carbon‐Intercalated 0D/2D Hybrid of Hematite Quantum Dots/Graphitic Carbon Nitride Nanosheets as Superior Catalyst for Advanced Oxidation
摘要： Efficient charge separation and sufficiently exposed active sites are important for light-driving Fenton catalysts. 0D/2D hybrids, especially quantum dots (QDs)/nanosheets (NSs), offer a better opportunity for improving photo-Fenton activity due to their high charge mobility and more catalytic sites, which is highly desirable but remains a great challenge. Herein, a 0D hematite quantum dots/2D ultrathin g-C3N4 nanosheets hybrid (Fe2O3 QDs/g-C3N4 NS) is developed via a facile chemical reaction and subsequent low-temperature calcination. As expected, the specially designed 0D/2D structure shows remarkable catalytic performance toward the removal of p-nitrophenol. By virtue of large surface area, adequate active sites, and strong interfacial coupling, the 0D Fe2O3 QDs/2D g-C3N4 nanosheets establish efficient charge transport paths by local in-plane carbon species, expediting the separation and transfer of electron/hole pairs. Simultaneously, highly efficient charge mobility can lead to continuous and fast Fe(III)/Fe(II) conversion, promoting a cooperative effect between the photocatalysis and chemical activation of H2O2. The developed carbon-intercalated 0D/2D hybrid provides a new insight in developing heterogeneous catalysis for a large variety of photoelectronic applications, not limited in photo-Fenton catalysis.
关键词： Fe2O3 QDs,g-C3N4 NS,charge separation,carbon-intercalated 0D/2D hybrid,Fe(III)/Fe(II) conversion
更新于2025-09-11 14:15:04
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Analysis of aqueous systems using all-inorganic perovskite CsPbBr3 quantum dots with stable electrochemiluminescence performance using a closed bipolar electrode
摘要： All-inorganic perovskite CsPbX3 (X = Cl, Br, I) quantum dots (QDs) have emerged as a new class of semiconductor nanocrystals, but the stability of CsPbX3 QDs in polar solvents is still a significant challenge. Since most targets in analytical chemistry, especially for biological detection, exist in an aqueous medium, this weakness seriously hampers practical analytical applications of CsPbX3 QDs. In this work, we introduce a closed bipolar electrode (BPE) to extend the application of perovskite QDs to aqueous systems. Based on the principle of conservation of charge in the electrode reactions at opposite ends of the BPE, the concentration of H2O2 in an aqueous medium can be detected by measuring the ECL intensity of CsPbBr3 QDs in an organic solution. Thus, for the first time, H2O2 in an aqueous system has been successfully analyzed using all-inorganic perovskite CsPbBr3 QDs with stable electrochemiluminescence performance combined with a closed bipolar electrode chip.
关键词： Bipolar electrode,Electrochemiluminescence,Perovskite,CsPbBr3 QDs
更新于2025-09-11 14:15:04
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Effects of Hexagonal Boron Nitride Sheets on the Optothermal Performances of Quantum Dots-Converted White LEDs
摘要： Recently, quantum dots-converted white light-emitting diodes (QDs-WLEDs) are attracting numerous attention due to their high luminous efficiency and excellent color quality. As for color conversion material, the quantum dots (QDs) are commonly embedded into a low-thermal-conductivity polymer matrix. In this case, their generated heat during the photoluminescence process can hardly be dissipated into the heat sink, leading to a high working temperature and reduced lifetime. Adding particles with high thermal conductivity to the QDs layer can enhance its thermal conductivity, and thus reduce QDs’ working temperature. At the same time, these particles may affect the optical properties of QDs. However, this problem has still not been deeply studied. In this article, we systematically investigated the effects of the highly thermal-conductive hexagonal boron nitride sheets (hBNSs) on the optothermal performances of QDs/phosphor film in white light-emitting diodes (WLEDs). The thermal conductivity of QDs/phosphor film was significantly increased by 24% after adding 5wt% of 45-μm-diameter hBNS. As for the optical performance, the transparency of the silicone gel film with 45-μm-diameter hBNS was much better than that with 6–9-μm-diameter hBNS under the same weight fraction. Furthermore, the scattering effect of hBNS plays a more important role in enhancing the light conversion performance of QDs than that of phosphor. At last, a color stability test showed the increasing rate of correlated color temperature (IRCCT) of hBNS-added WLEDs are 21% smaller than that of common WLEDs after working 153 h, meaning a better QDs stability in hBNS-added WLEDs.
关键词： light conversion,quantum dots (QDs),Hexagonal boron nitride sheets (hBNSs),thermal conductivity
更新于2025-09-11 14:15:04