CERAMICS INTERNATIONAL
·
2021
·
IF 4.527
Yefeng Feng,Hongrong Qiu,Wei Xiong,Jiangqiong Wang,Maolin Bo,Qihuang Deng
High dielectric response and low leakage conduction are desired in polymer/ceramic composite dielectrics for capacitive energy storage. Rational structural design of hybrid ceramic filler can lead to a balance between high dielectric constant and insulation in composites. In this study, high dielectric constant and breakdown strength were achieved in fluoropolymer/mesoporous silica@CdTe nanocomposite films . Mesoporous silica nanoparticles (MSNs) were employed owing to their high insulation and complex electron-leakage channel. CdTe quantum dots combined with pore-canal inwalls of MSNs were employed because of their internal exciton polarization and MSNs/CdTe interface polarization. Compared with polymer/MSNs composites, polymer/MSNs@CdTe composites exhibited remarkably improved dielectric constant, slightly increased dielectric loss, and slightly reduced breakdown strength. High dielectric constant of ternary composites was ascribed to exciton orientation inside CdTe and interfacial dipole orientation between MSNs and CdTe. High breakdown strength was attributed to high insulation in MSNs and long-range electron transfer inside MSNs@CdTe. An optimal ternary composite with 12 wt% MSNs@CdTe showed a high dielectric constant of ~56, low dielectric loss of ~0.19 at 100 Hz, and high breakdown strength of ~308 MV m -1 . The results of this study can provide insights for enabling large-scale fabrication of modern composite dielectrics based on mesoporous particles@semi-conductive quantum dots fillers.
研究领域:
材料科学
·
物理学
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Environmental Science-Processes & Impacts
·
2026
·
IF 4.2
Jing Wang,Jiaxuan Li,Xinyi Peng,Wenbin Mu,Shuyang Guo,Songrui Yang,Xinping Yu,Lining Zhao
This study investigated the aggregation, dissolution, and sedimentation of Zn-doped CdTe quantum dots (CdTe: Zn2+ QDs) incubating with or without three different dissolved organic matter (DOM) in artificial freshwater and seawater as well as the underlying mechanisms. Our results found that water composition and DOM species significantly affected the above behaviors. Compared with in freshwater, bare QDs and QDs-DOM in seawater formed larger aggregates, released higher Cd2+ contents and sedimented faster. Under most circumstances, DOM inhibited QDs aggregation through enhancing electrosteric stabilization and accelerated QDs dissolution via promoting their contacts. Bovine serum albumin (BSA), humic acid (HA) and fulvic acid (FA) formed the largest, medium and smallest aggregates with QDs in freshwater, which were well agreed with the molecular weight of DOM and the stoichiometry of QDs-DOM interactions. QDs-FA released the largest content of Cd2+ in freshwater since FA has the strongest capacity of complexing QDs. In both artificial waters, HA and FA adsorption accelerated the sedimentation of QDs; while BSA impeded the sedimentation. Isothermal titration calorimetric experiments found that the major driving forces of all QDs-DOM interactions are hydrophobic forces. The stoichiometries for HA, FA and BSA binding to QDs are 6.3, 4.7 and 9.4, respectively. Results from multi-spectroscopic experiments suggested that the nano-form of QDs mainly interact with aromatic skeletons in HA rather than Cd2+. This study could shed light on predicting the fate and assessing the risk of QDs in aquatic environment.
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ANALYTICAL BIOCHEMISTRY
·
2023
·
IF 2.9
You Quan Shi,Zhao Xu,Le Wang,Kang Wang,Li Xu,Heng Zheng
It is particularly meaningful to therapeutic drug monitoring (TDM) of mycophenolic acid (MPA) for transplant patients to maximize the drug efficacy and minimize the adverse effect. In this study, a novel fluorescence and colorimetric dual-readout probe was put forward to fast and reliable detect MPA. The blue fluorescence of MPA was largely enhanced in the presence of poly (ethylenimine) (PEI), while the red fluorescence of [email protected] 2 (silica-coated CdTe quantum dots) provided a reliable reference signal. Hence, combining PEI 70,000 and [email protected] 2 , a fluorescence and colorimetric dual-readout probe could be constructed. For fluorescence measurement of MPA, the linearity was obtained in the MPA concentration range of 0.5–50 μg/mL, with a limit of detection (LOD) of 33 ng/mL. For the visual detection, the fluorescent colorimetric card was established in the MPA concentration from 0.5 to 50 μg/mL corresponding to the fluorescence color from red to violet and then to blue, which could be used for semi-quantification. Furthermore, in the light of the ColorCollect APP by the smartphone, the ratio of blue and red brightness values was linear with the MPA concentration from 1 to 50 μg/mL; thus, quantification of MPA could be realized by APP with the LOD of 83 ng/mL. The developed method was successfully applied to the analysis of MPA in the plasma samples of three patients after oral administration of mycophenolate mofetil , which was the prodrug of MPA. The result was comparable to those obtained by the clinically widely-used enzyme multiplied immunoassay technique. The developed probe was fast, cost-effective and operational convenience, and possessed high potential for TDM of MPA.
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MICROCHIMICA ACTA
·
2015
·Vol. 183
·期 2
·667-673
·
IF 3.741
Xu Shuxia,Li Jialin,Li Xianming,Su Min,Shi Zeming,Zeng Ying,Ni Shijun
This article describes a nonenzymatic chemiluminescence resonance energy transfer (CRET) system for highly sensitive determination of hydroquinone. It was found that the Co(II)-catalyzed luminescence of luminol in pH 11.5 solution is transferred to CdTe quantum dots (QDs) via a CRET mechanism. Hydroquinone is oxidized by H 2 O 2 to benzoquinone which quenches the fluorescence of the QDs. The enhancement is attributed to the adsorption of Co(II) on the surface of the negatively charged QDs. The CRET system was applied in an assay for hydroquinone that has a detection limit of 0.17 nmol L −1 . The detection limit was lower by factors between 100 and 250,000 than earlier reported methods. The assay was successfully applied to the quantitation of hydroquinone in (spiked) water samples, with recoveries ranging from 95 % to 106 %, and relative standard deviations between 0.5 % and 2.4 %.
A Co(II)-luminol-H 2 O 2 -quantum dot chemiluminescence resonance energy transfer system was developed for highly sensitive detection of hydroquinone. Strong signals were observed due to energy transfer between luminol donor and CdTe quantum dots which is catalyzed by Co(II).
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MICROCHEMICAL JOURNAL
·
2021
·
IF 4.821
Yiyun Zhang,Wenwen Zhang,Liming Zhang,Guangsan Song,Ningwei Wang,Wanzhen Xu,Weihong Huang
An imprinted electrochemical sensor based on multifunctional multi-walled carbon nanotubes was synthesized for detection of bisphenol A (BPA). Molecularly imprinted polymers (MIPs) consist carboxylated quantum dots grafted with aminated multi-walled carbon nanotubes as a carrier, BPA as a template, and 3-aminopropyltriethoxysilane (APTES) as a monomer. The successful recombination of quantum dots allows the electrodes to translate small differences in concentration into large changes in current response. Modified materials were discussed by TEM, SEM, FT-IR, Fluorescence, XRD, together with a series of characterization of electrochemical behavior. The MIPs displayed well selectivity towards BPA and hardly showed response to interferes. Also, the sensor has a high stability (RSD of 5.17%) and repeatability (RSD of 0.43%). Moreover, the current response has a linear relationship range from 0.05 to 50 nmol L −1 , with a detection limit of 0.015 nmol L −1 . Finally, the modified electrode was utilized for the detection of 3 kinds of water samples which indicated that the sensor has potential for future applications in trace detection of BPA in environment water.
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NEW JOURNAL OF CHEMISTRY
·
2018
·Vol. 42
·期 19
·15743-15749
·
IF 3.201
Jing Wang,Daquan Li,Xinyue Liu,Yu Qiu,Xiao Peng,Liang Huang,Huimin Wen,Jun Hu
Aqueous N-acetyl-L-cysteine (NAC)-capped CdTe quantum dots (QDs) are prepared in one step by using sodium tellurite as a tellurium source and sodium borohydride as a reductant. The fluorescence (FL) emissions of the QDs are tunable between 514 and 753 nm. The effects of NAC/Cd, Cd/Te molar ratios, and pH values on the photoluminescence quantum yield (PLQY) of the QDs have been systematically studied. They display a high PLQY of up to 52.83%, with uniform narrow-size distributions. Furthermore, the obtained green- and red-emissive CdTe QDs are applied to explore the impact of QD size on the FL response toward glutathione (GSH) by a “turn-on” strategy. The results imply that the large-sized CdTe QDs with red FL are more suitable for detecting GSH than the small-sized QDs with green FL. The possible mechanism is also investigated.
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SENSORS AND ACTUATORS B-CHEMICAL
·
2014
·
IF 3.84
Jing Wang,Na Li,Feng Shao,Heyou Han
Highly luminescent, good stable and low toxic N-acetyl- l -cysteine (NAC) capped CdTe/CdS@ZnS–SiO 2 near-infrared (NIR)-emitting quantum dots (QDs) were successfully fabricated in aqueous solution via a microwave irradiation reduction route, in which thiol-capped CdTe/CdS QDs were employed as core templates and ZnCl 2 , NAC and tetraethyl orthosilicate as shell precursors. This presented ZnS-like clusters filled hybrid SiO 2 model not only greatly improved the brightness and stability of original CdTe/CdS QDs, but also tremendously decreased the cytotoxicity towards HeLa cells. Furthermore, it was found that Hg 2+ could effectively selective quench the QD NIR emission based on electron transfer process. On the basis of this fact, a simple, rapid and specific method for trace Hg 2+ determination was proposed. Under optimal conditions, the fluorescence intensity decreased linearly with the concentration of Hg 2+ ranging from 5.0 × 10 −9 to 1.0 × 10 −6 M and the limit of detection for Hg 2+ was 1.0 × 10 −9 M ( S / N = 3). As practical applications, the novel NIR sensor has been demonstrated to monitor and image Hg 2+ level in milk power and HeLa cells respectively with satisfactory results obtained.
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DYES AND PIGMENTS
·
2014
·
IF 3.468
Jie Sha,Cuiyan Tong,Haixia Zhang,Lijuan Feng,Bingxin Liu,Changli Lü
This paper reported a facile method for fabricating CdTe quantum dots decorated fluorescent mesoporous silica nanoparticles containing poly(p-phenylenevinylene) by electrostatic interaction in aqueous solution. The resulted fluorescent hybrid nanomaterials showed the dual-emission centered at 500 nm and 717 nm, which can be used as a fluorescent probe to detect Cu 2+ in water through fluorescence resonance energy transfer. Cu 2+ can be captured by the amino groups of the polyethyleneimine to form an absorbent complex, resulting in a strong quenching of red-emission from CdTe quantum dots on the surface of nanoparticles via energy transfer. However, the green-emission of poly(p-phenylenevinylene) remained. Therefore the addition of Cu 2+ induced the fluorescent evolution of the nanoprobe from red to green. The nanoprobe provided an efficient platform for the sensing of Cu 2+ with a detection limit of 31.2 nM. Compared with pure quantum dots, the nanoprobe can distinguish Cu 2+ from Hg 2+ .
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SENSORS AND ACTUATORS B-CHEMICAL
·
2015
·
IF 4.097
Xiao Wei,Tongfan Hao,Yeqing Xu,Kai Lu,Hongji Li,Yongsheng Yan,Zhiping Zhou
In this paper, we develop a method by using octadecyl-4-vinylbenzyl-dimethyl-ammonium chloride (OVDAC) as a surfactant to transfer aqueous CdTe quantum dots (QDs) with excellent fluorescent property to organic solvent, after a surface imprinting-directing polymerization process, a high-performance aqueous QDs-polymer fluorescent imprinted composite sensor was obtained and used for highly selective recognition of λ-cyhalothrin (LC). Here, OVDAC was first used in the fabrication of fluorescent imprinted composite sensors, and the OVDAC-modified CdTe QDs were used as the solid supports and auxiliary monomers. Through this novel strategy, strong fluorescence of aqueous QDs was inherited in the resultant MIPs . After the experimental conditions were optimized, a linear relationship was obtained covering the linear range of 0.1–16 μmol L −1 with a correlation coefficient of 0.9989 and a high imprinting factor about 5.99. In addition, the MIPs-OVDAC/CdTe QDs had higher molecular selectivity and sensing specificity than two kinds of molecularly imprinted silica coated QDs which were prepared by the Stöber method and reverse microemulsion method, respectively. The developed method was applicable to routine trace determination of LC in real examples. This study provides a general strategy to fabricate high-performance fluorescent sensors based on QDs which were originally water-soluble for highly selective detection of environmental pollutants.
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ELECTROCHIMICA ACTA
·
2013
·
IF 3.777
Yanhu Wang,Dejin Zang,Shenguang Ge,Lei Ge,Jinghua Yu,Mei Yan
Driven by the urgent demand of high-selectively point-of-care testing device for pesticide, molecular imprinting-photoelectrochemistry (MI-PEC) was introduced into microfluidic paper-based analytical strategy to design a novel paper-based photoelectrochemical (paper-based PEC) protocol. The MI-PEC strategy was constructed based on CdTe quantum dots dotted molecular imprinted polymers (CdTe QDs@MIPs), and triggered by a common ultraviolet lamp (∼365 nm, 50$). The paper-based PEC sensor was fabricated by immobilizing CdTe QDs@MIPs on paper-based screen-printed working electrodes (WEs) via gold nanoparticles (Au NPs), which was electrodeposited on the surface of WE to improve the electron transfer efficiency for high sensitivity. Using S-fenvalerate as model analyte, the produced photocurrent from the proposed paper-based MI-PEC sensor upon ultraviolet radiation decreased with the increasing concentrations of S-fenvalerate solution, and the quenched paper-based MI-PEC showed a low detection limit of 3.2 × 10 −9 mol L −1 . This study has made a successful attempt in the development of highly selective and sensitive photoelectrochemical sensor for S-fenvalerate monitoring.
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SENSORS AND ACTUATORS B-CHEMICAL
·
2016
·
IF 4.758
Le Wu,Zheng-zhong Lin,Hui-ping Zhong,Xiao-mei Chen,Zhi-yong Huang
A fluorescent probe based on CdTe quantum dots (QDs) coated with molecularly imprinted polymers (MIPs) was fabricated for the determination of malachite green (MG) by the strategy of fluorescence resonance energy transfer (FRET). The MIP-coated QDs were synthesized through precipitation polymerization using acrylamide and ethylene glycol dimethacrylate as monomer and cross-linker, respectively. The optimum molar ratio of MG, monomer and cross-linker was 1:8:40 in 60 mL of acetonitrile, and the polymerization time was 28 h. The MIP-coated QDs, with an average diameter around 290 nm, showed excellent fluorescence emission in 500–700 nm at λ ex 370 nm. The probe exhibited fluorescence quenching response to MG selectively within only 5 min at the concentrations from 0.1 to 20 μmol L −1 . The fluorescent probe was successfully used to detect MG in water and fish samples with a detection limit of 0.059 μmol L −1 (3 σ , n = 9). The spiked recoveries, from 94.8% to 98.1% for water samples, and 98.1% to 106.2% for fish samples, respectively, indicated that the as-prepared MIP-coated QDs could be used as a fluorescent probe to detect MG rapidly in water and fish samples.
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JOURNAL OF ELECTROANALYTICAL CHEMISTRY
·
2024
·
IF 4.1
Shuangshuang Tian,Liqiang Chen,Hong Zhang,Liangquan Sheng,Xinxin Wang,Deqian Huang
CdTe quantum dots (CdTe QDs) were synthesized using mercaptopropionic acid (MPA) as a stabilizer. The electrochemiluminescence (ECL) mechanism of CdTe QDs was examined at cathodic (−2.1 to 0 V) and anodic (0–1.5 V) potentials. Utilizing dissolved oxygen as a co-reactant for cathodic CdTe QDs, the addition of phenylephrine hydrochloride (PEH) triggers a burst effect on the intermediate OH at the electrode surface, resulting in a reduction of electron hole formation. Consequently, a novel method for detecting PEH in the concentration range of 0.2–10 μM has been developed. A strong linear correlation was observed between Lg C PEH and the ECL intensity ratio ( I/I 0 ) of cathodic CdTe QDs, with a detection limit of 37 nM. Tri- n -propylamine (TPrA) was utilized as a co-reactant for the anode of CdTe QDs. The addition of paliperidone (PP) occupies the oxidized vacancies of TPrA, leading to a diminished ECL signal. A new method was subsequently established to detect PP in the concentration range of 0.2 nM–1.0 μM with a detection limit of 18 pM. This method has been successfully applied to detect PEH in urine and in compound tropicamide eye drops, as well as to quantify PP content in paliperidone sustained-release tablets and serum, demonstrating excellent recovery and selectivity.
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