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Green emitted CdSe@ZnS quantum dots for FLIM and STED imaging applications
摘要： Inorganic quantum dots (QDs) have excellent optical properties, such as high fluorescence intensity, excellent photostability and tunable emission wavelength, etc., facilitating them to be used as labels and probes for bioimaging. In this study, CdSe@ZnS QDs are used as probes for Fluorescence lifetime imaging microscope (FLIM) and stimulated emission depletion (STED) nanoscopy imaging. The emission peak of CdSe@ZnS QDs centered at 526 nm with a narrow width of 19 nm and the photoluminescence quantum yield (PLQY) was 64%. The QDs presented excellent anti-photobleaching property which can be irradiated for 400 min by STED laser with 39.8 mW. The lateral resolution of 42.0 nm is demonstrated for single QDs under STED laser (27.5 mW) irradiation. Furthermore, the CdSe@ZnS QDs were for the first time used to successfully label the lysosomes of living HeLa cells and 81.5 nm lateral resolution is obtained indicating the available super-resolution applications in living cells for inorganic QD probes. Meanwhile, Eca-109 cells labeled with the CdSe@ZnS QDs was observed with FLIM, and their fluorescence lifetime was around 3.1 ns, consistent with the in vitro value, suggesting that the QDs could act as a satisfactory probe in further FLIM-STED experiments.
关键词： CdSe@ZnS QDs,living cells,STED,FLIM
更新于2025-09-19 17:13:59
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Signal-switchable lab-on-paper photoelectrochemical aptasensing system integrated triple-helix molecular switch with charge separation and recombination regime of type-II CdTe@CdSe core-shell quantum dots
摘要： Herein, a new “on-off-on” signal switch system combined triple helix molecular switch with efficient charge separation and transfer between different sensitization units was designed for the ultrasensitive photoelectrochemical (PEC) determination of prostate-specific antigen (PSA). Concretely, the initial “signal-on” state was obtained via the cascaded sensitization structure consisting of type-II CdTe@CdSe core-shell quantum dots (QDs), CdS QDs, and ZnO nanotubes, which were assembled on Au nanoparticles modified paper fibers with the aid of signal transduction probe (STP). Thereinto, the type-II CdTe@CdSe QDs with hole-localizing core and electron-localizing shell could enable the ultrafast charge transfer and retard the charge recombination, magnifying the initial photocurrent response and preserving the high efficiency of signal-switchable PEC aptasensing system. Subsequently, the PSA aptamer (PSA-Apt) modified with gold nanoparticles (GNPs) was introduced by the hybridization of PSA-Apt with STP and the hairpin configuration of STP changed from closed to open state, forming a triple-helix structure. Hence, the CdTe@CdSe QDs labeled on the terminal of STP moved away from the electrode surface while the GNPs kept attached close to it. The proposed aptasensor turned to “signal-off” state because of the dual inhibition of vanished cosensitization effect and signal quenching effect of GNPs. Upon the target recognition, the triple-helix structure was perturbed with the formation of DNA-protein complex and the recovery of STP hairpin structure, resulting in the second “switch-on” state. Based on the target-induced photocurrent enhancement, the proposed PEC aptasensor was utilized for the determination of PSA with high sensitivity, persuasive selectivity, and excellent stability.
关键词： Prostate-specific antigen,Type-II CdTe@CdSe QDs,Signal-switchable,Triple helix molecular switch,Photoelectrochemical
更新于2025-09-19 17:13:59
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High staility of silica-wrapped CsPbBr3 perovskite quantum dots for light emitting application
摘要： Encapsulating quantum dots (QDs) into other medium has been considered as an efficacious method to avoid the fluorescence degradation of QDs. Here, we proposed a facile method to embed CsPbBr3 perovskite QDs in silica matrix derived from (3-aminopropyl)triethoxysilane (APTES) at room temperature in open air. The QDs/SiO2 composite was extracted from the sol-gel solution by using a precipitation-encapsulation method assisted with APTES. As-prepared composite powder possess a high photoluminescence quantum yield (PLQY) of 68% and a full width at half maximum (FWHM) of ~23 nm. The QDs/SiO2 compounds show excellent stability after the five heating cycles (105 °C) and a continuous xenon irradiation (500 W, 70 °C). Besides, the products remain 94.3% and 98.6% photoluminescence (PL) intensity after 30 days of storage (25 °C) and 96 hours of ultraviolet (UV) irradiation (λ= 365 nm) respectively. The white light-emitting diode (LED) was fabricated by coating green-emitting CsPbBr3@SiO2 composite powder and commercial red phosphors on blue chip. The fabricated white LED performed excellent light characteristics with a luminous efficacy (ηL) of 58.9 lmW-1 and a correlated color temperature (CCT, Tc) of 5829 K (current = 20 mA), it also display a wide color gamut with 126.8% of National Television System Committee (NTSC) color triangle area.
关键词： white LED,stability,perovskite QDs,CsPbBr3,SiO2
更新于2025-09-19 17:13:59
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Facile Preparation of MnO <sub/>2</sub> Quantum Dots with Enhanced Fluorescence via the Micro-environment Engineering with the Assistance of Some Reductive Biomolecules
摘要： MnO2 nanomaterials have been aroused wide attention because of their nano-enzyme activity, redox property, good biocompatibility and therapy-related activities. However, not any report about self-luminescent MnO2 materials are concerned to date, which greatly hampered their further development in various fields. In this paper, luminescent MnO2 quantum dots (MnO2 QDs) has been firstly prepared via a facile one-step ultrasonic method. With the assistant of bovine serum albumin (BSA) or cysteine (Cys), the synthesized MnO2 QDs (BSA-MnO2 QDs or Cys-MnO2 QDs) display strongly enhanced fluorescence (FL). The prepared BSA-MnO2 QDs with the particles size of about 1-2 nm show the maximum excitation and emission peaks at 320 and 410 nm with excellent salt stability, anti-photo bleaching ability and time stability. It is confirmed that BSA play the dual function as the exfoliating agent to promote the exfoliation of bulk MnO2 nanosheets and as the capping agent to provide a friendly micro-environment for MnO2 QDs. Ag ions can destroy the micro-environment of BSA-MnO2 QDs owing to the in-situ formation of Ag nanoparticles (Ag NPs) mediated by the BSA on the surface of the QDs. Then these Ag NPs can quench the FL intensity of the QDs by fluorescence resonance energy transfer. However, the FL strength of BSA-MnO2 QDs is recovered after adding H2O2 and NaHS since they may react with Ag NPs to produce Ag+ and Ag2S, which further confirmed the role of BSA. This work not only opens a facile and universal avenue to synthesize luminescent MnO2 QDs with enhanced FL, but provide a possible sensing platform through tuning the micro-environment of MnO2 QDs. The MnO2 QDs with outstanding performance may show great potential as promising fluorescent probes in the fields of biological imaging, optical sensing, drug delivery and therapy.
关键词： micro-environment engineering,reductive biomolecules,MnO2 QDs,enhanced fluorescence,Ag ions
更新于2025-09-19 17:13:59
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Molybdenum Disulfide Nanosheet/Quantum Dot Dynamic Memristive Structure Driven by Photoinduced Phase Transition
摘要： MoS2 2D nanosheets (NS) with intercalated 0D quantum dots (QDs) represent promising structures for creating low-dimensional (LD) resistive memory devices. Nonvolatile memristors based 2D materials demonstrate low power consumption and ultrahigh density. Here, the observation of a photoinduced phase transition in the 2D NS/0D QDs MoS2 structure providing dynamic resistive memory is reported. The resistive switching of the MoS2 NS/QD structure is observed in an electric field and can be controlled through local QD excitations. Photoexcitation of the LD structure at different laser power densities leads to a reversible MoS2 2H-1T phase transition and demonstrates the potential of the LD structure for implementing a new dynamic ultrafast photoresistive memory. The dynamic LD photomemristive structure is attractive for real-time pattern recognition and photoconfiguration of artificial neural networks in a wide spectral range of sensitivity provided by QDs.
关键词： neuromorphic computing,photoinduced phase transition,2D crystals and QDs,dynamic photomemristors,liquid phase exfoliation
更新于2025-09-19 17:13:59
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A Review on Quantum Dots Modified g-C3N4-Based Photocatalysts with Improved Photocatalytic Activity
摘要： In the 21st century, the development of sustainable energy and advanced technologies to cope with energy shortages and environmental pollution has become vital. Semiconductor photocatalysis is a promising technology that can directly convert solar energy to chemical energy and is extensively used for its environmentally-friendly properties. In the field of photocatalysis, graphitic carbon nitride (g-C3N4) has obtained increasing interest due to its unique physicochemical properties. Therefore, numerous researchers have attempted to integrate quantum dots (QDs) with g-C3N4 to optimize the photocatalytic activity. In this review, recent progress in combining g-C3N4 with QDs for synthesizing new photocatalysts was introduced. The methods of QDs/g-C3N4-based photocatalysts synthesis are summarized. Recent studies assessing the application of photocatalytic performance and mechanism of modification of g-C3N4 with carbon quantum dots (CQDs), graphene quantum dots (GQDs), and g-C3N4 QDs are herein discussed. Lastly, challenges and future perspectives of QDs modified g-C3N4-based photocatalysts in photocatalytic applications are discussed. We hope that this review will provide a valuable overview and insight for the promotion of applications of QDs modified g-C3N4 based-photocatalysts.
关键词： organic pollutant photodegradation,H2 production,graphitic carbon nitride (g-C3N4),photocatalysis,CO2 reduction,quantum dots (QDs)
更新于2025-09-19 17:13:59
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Stable and efficient hybrid Ag-In-S/ZnS@SiO2-carbon quantum dots nanocomposites for white light-emitting diodes
摘要： As a promising energy-saving technique, the eco-friendly and low-cost solid-state white light-emitting diodes (WLEDs) based on quantum dots (QDs) have been widely studied. Herein, a WLED device prepared by core–shell structure nanocomposites based on Ag-In-S/ZnS@SiO2 quantum dots (AIS@SiO2) and carbon quantum dots (CDs) was successfully constructed. CDs were combined onto the surface of AIS@SiO2 QDs to synthesize Ag-In-S/ZnS@SiO2-Carbon quantum dots (AIS-CDs) nanocomposites with a white-light emission, which successfully overcome the quenching effect of CDs induced by conventional aggregation. The as-prepared AIS-CDs nanocomposites presented high stability and a photoluminescence quantum yield (PLQY) of 35%. Moreover, the corresponding AIS-CDs nanocomposites-based WLEDs demonstrated the color coordinate of (0.32, 0.33), which is comparable to the pure white light (0.33,0.33); Furthermore, the luminous efficiency of the as-prepared WLEDs showed 15.1 lm W-1. These results reported herein may open up a new avenue for the development of high-performance, low-cost, and environmentally-friendly WLEDs.
关键词： WLEDs,Ag-In-S/ZnS QDs,Nanocomposites,CDs
更新于2025-09-19 17:13:59
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Ratiometric fluorescent paper-based sensor based on CdTe quantum dots and graphite carbon nitride hybrid for visual and rapid determination of Cu <sup>2+</sup> in drinks
摘要： A simple and effective ratiometric fluorescent sensor of CdTe QDs/GCNNs for on-site and rapid analysis of Cu2+ has been established by mixing physically CdTe QDs and graphite carbon nitride (GCNNs). Two emissions peaks of CdTe QDs at 572 nm and GCNNs at 436 nm are both excitated at 340 nm. Under a UV lamp, fluorescent of traffic yellow CdTe QDs is linearly quenched by Cu2+ (as the detection signal), while blue GCNNs remains unchanged (as the reference), resulting in a distinguishable color change gradually from pink yellow to blue. The limit of detection (LOD) of this new sensor for Cu2+ is as low as 0.47 ng mL-1 with 1.4 % RSD. The established method has been successfully applied to detection of Cu2+ in various drinks with satisfactory results. Moreover, a paper-based sensor, which has been prepared by soaking cellulose acetate membrane in CdTe QDs/GCNNs sensor solution, has a wide semi-quantitative detection range for Cu2+ (0.01~5.0 μg mL-1). It has realized successfully on-site and rapid determination of Cu2+ in red wine without any pretreatment procedure and is of great promotion and application value in determination of Cu2+ in liquid samples.
关键词： CdTe QDs/GCNNs sensor,Cu2+,on-site,ratiometric fluorescence,paper-based
更新于2025-09-19 17:13:59
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Vitamin B6 cofactors guided highly selective fluorescent turn-on sensing of histamine using beta-cyclodextrin stabilized ZnO quantum dots
摘要： Histamine, one of the most important biogenic amines (BAs) is considered as food hazard and therefore various agencies have fixed threshold in different food and beverages. In this manuscript, two novel fluorescent turn-on probes were developed for the instantaneous detection of histamine. The β-cyclodextrin (β-CD) capped ZnO quantum dots (QDs) were decorated with the vitamin B6 cofactors like pyridoxal 5′-phosphate (PLP) and pyridoxal (Py) by forming host-guest inclusion complexation between the capped β-CD and PLP/Py. The cofactors decorated QDs (ZnO@PLP and ZnO@Py) were applied for the sensing of BAs. Addition of histamine to the ZnO@PLP and ZnO@Py solution resulted selective fluorescence enhancement at 473 nm and 460 nm, respectively. Without any interference from the other tested BAs, the fluorescence response of the probes ZnO@PLP and ZnO@Py showed good linearity to histidine concentration from 2.49 to 24.4 μM and 7.44 to 47.6 μM with the detection limit down to 0.59 μM and 0.97 μM, respectively.
关键词： Vitamin B6 cofactors,ZnO QDs,Fluorescent turn-on sensor,Histamine
更新于2025-09-19 17:13:59
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More Than 9% Efficient ZnSeTe Quantum Dot-Based Blue Electroluminescent Devices
摘要： We explore both synthesis of Cd-free blue quantum dots (QDs) with high-quality photoluminescence (PL) characteristics and fabrication of high-efficiency QD-light-emitting diodes (QLEDs). True blue (445 nm)-emissive, multishelled ZnSeTe QDs with a high PL quantum yield of 84% and sharp bandwidth of 27 nm are prepared. To obtain a better electron transport layer (ETL) material, surface of ZnMgO nanoparticles (NPs) is modified by additional Mg reaction, leading to the possible formation of Mg(OH)2 layer on the surface-modified ZnMgO (m-ZnMgO) NPs. The presence of Mg(OH)2 overlayer, origin for the desirably reduced electron mobility, is supposedly responsible for the improved charge balance of QD emissive layer (EML). The Mg(OH)2 layer is further found to alleviate the emission quenching of QD EML. Combining blue ZnSeTe QDs and m-ZnMgO NP ETL, highly bright, efficient blue QLEDs with the record luminance of 2904 cd/m2 and external quantum efficiency of 9.5% are demonstrated.
关键词： electron transport layer,Mg(OH)2 overlayer,electroluminescent devices,photoluminescence,ZnSeTe QDs,Cd-free blue quantum dots,QLEDs,ZnMgO nanoparticles
更新于2025-09-19 17:13:59