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Significant Lifetime Enhancement in QLEDs by Reducing Interfacial Charge Accumulation via Fluorine Incorporation in the ZnO Electron Transport Layer

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Nano-Micro Letters 2022年第12期14卷 432-446页

作者： Dong Seob Chung Tyler Davidson-Hall Giovanni Cotella Quan Lyu Peter Chun Hany Aziz Department of Electrical and Computer Engineering Waterloo Institute for NanotechnologyUniversity of Waterloo200 University Avenue WestWaterlooON N2L 3G1Canada Ipswich Research Centre Huawei Technologies Research&Development(UK)Ltd.Phoenix House(B55)Adastral ParkIpswich IP53REUK Ottawa IC Laboratory Huawei Canada19 Allstate ParkwayMarkhamON L3R 5B4Canada

ZnO nanoparticles are widely used for the electron transport layers(ETLs)of quantum dots light emitting devices(QLEDs).In this work we show that incorporating fluorine(F)into the ZnO ETL results in significant enhancement in device electroluminescence stability,leading to LT50 at 100 cd m^(−2) of 2,370,000 h in red QLED,47X longer than the control devices.X-ray photo-electron spectroscopy,time-of-flight secondary ion mass spectroscopy,photoluminescence and electrical measurements show that the F passivates oxygen vacancies and reduces electron traps in *** photoluminescence versus bias measurements and capacitance-voltage-luminance measurements reveal that the CF4 plasma-treated ETLs lead to increased electron concentration in the QD and the QD/hole transport layer interface,subsequently decreasing hole accumulation,and hence the higher *** findings provide new insights into the critical roles that optimizing charge distribution across the layers play in influencing stability and present a novel and simple approach for extending QLED lifetimes.

关键词： Colloidal quantum dots Quantum dots light emitting device Device stability zinc oxide nanoparticles Fluorine

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Speciation in nanosecond laser ablation of zinc in water

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Science China(Physics,Mechanics & Astronomy) 2022年第7期65卷 90-98页

作者： Stefan Reich Yannis Klügl Anna Ziefuss RenéStreubel Jorg Gottlicher Anton Plech Institute for Photon Science and Synchrotron Radiation Karlsruhe Institute of TechnologyKarlsruhe D-76021Germany Department of Technical ChemistryⅠand Center for Nanointegration Duisburg-Essen University of Duisburg-EssenEssen D-45141Germany Fraunhofer Institute for High-Speed Dynamics Ernst-Mach-Institute(EMI)Freiburg 79104Germany

In situ experimental methods have been applied to resolve mass flow and chemical speciation in the pulsed laser ablation of zinc in water. The chemical speciation has been resolved by time-resolved μ-X-ray absorption spectroscopy and mapped onto the macroscopic mass flow during material ejection from the metallic target and bubble dynamics of evaporated water. Large particles and agglomerates have been detected via dark-field X-ray imaging with a Shack-Hartmann sensor. The characteristic of the dynamics is that the vapor bubble is nearly homogeneously filled with ablated material. This persists during bubble collapse,which means that the ablated particles are captured and retracted towards the target. Limited mass escape is indicated by the X-ray absorption signal. Importantly, the near-edge structure at the Zn-K;transition delivers information on the chemical state of the ejected material. It clearly confirms that oxidation is not present within the bubble phase and the following sub-millisecond time scale. The oxidation proceeds on Zn nanoparticles in suspension on a second to minute course. Within the first microseconds,a Zn atom phase is detected that resembles Zn vapor. The addition of either reductive NaBH;or oxidative HAuCl;to the water phase influences the quantity of the atom contribution moderately, but does not influence the initial atom phase. Such behavior must be understood in terms of the nanosecond pulse excitation. After ejected material and a plasma is formed within the pulse duration of 7 ns the laser is able to further heat the ejecta and transform it partly into vapor. Correspondingly, the coupling of energy into the ablation zone as followed by plasma intensity and bubble size follows a threshold behavior as a function of laser fluence, marking the onset of laser-plasma heating. The reaction conditions inside the bubble are probably reductive due to the concomitant formation of excess hydrogen.

关键词： laser ablation in liquids elemental speciation X-ray absorption spectroscopy oxidation zinc oxide nanoparticles

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Unravel the potential of zinc oxide nanoparticle-carbonized sawdust matrix for removal of lead(Ⅱ) ions from aqueous solution

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Chinese Journal of Chemical Engineering 2021年第1期34卷 92-102页

作者： Racheal Aigbe Doga Kavaz Department of Environmental Science Cyprus International UniversityNicosiaMersin 10Turkey Environmental Research Centre Cyprus International UniversityNicosiaMersin 10Turkey Department of Bioengineering Cyprus International UniversityNicosiaMersin 10Turkey

zinc oxide nanoparticles(ZnOnp) are molecular nanoparticles synthesized by a chemical precipitation method from zinc nitrate tetrahydrate and sodium *** sawdust(CSD) was prepared from sawdust obtained from a local wood *** matrix of both provides a better material as an *** present study applied the functionality of ZnOnp,CSD,and ZnOnp-CSD matrix as adsorbent materials for the removal of Pb(Ⅱ) ions from aqueous *** method of batch process was employed to investigate the potential of the *** influence of pH,contact time,initial concentration of adsorbate,the dosage of adsorbents,and the temperature of adsorbate-adsorbent mixture on the adsorption capacity were *** adsorption isotherm studies indicate that both Freundlich and Langmuir isotherms were suitable to express the experimental data obtained with theoretical maximum adsorption capacities(q_(m)) of 70.42,87.72,and 92.59 mg·g^(-1) for the adsorption of Pb(Ⅱ) ions onto ZnOnp,CSD,and ZnOnp-CSD matrix,*** separation factors(R_(L)) calculated showed that the use of the adsorbents for the removal of Pb(Ⅱ) ions is a feasible process with R_(L) <*** thermodynamic parameters obtained revealed that the processes are endothermic,feasible,and spontaneous in nature at 25-50℃.Evaluation of the kinetic model elected that the processes agreed better with pseudo-second order where the values of rate constant(k_2) obtained for the adsorption of Pb(Ⅱ) ions onto ZnOnp,CSD,and ZnOnp-CSD matrix are 0.00149,0.00188,and 0.00315 g·mg^(-1)·min^(-1),*** reusability potential examined for four cycles indicated that the adsorbents have better potential and economic value of reuse and the ZnOnp-CSD matrix indicates improved adsorbent material to remove Pb(Ⅱ) ions from aqueous solution.

关键词： zinc oxide nanoparticles Carbonized saw dust Matrix Batch process Reusability potential

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Tapered Optical Fiber-Based LSPR Biosensor for Ascorbic Acid Detection

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Photonic Sensors 2021年第4期11卷 418-434页

作者： Guo ZHU Lokendra SINGH Yu WANG Ragini SINGH Bingyuan ZHANG Fengzhen LIU Brajesh Kumar KAUSHIK Santosh KUMAR Shandong Key Laboratory of Optical Communication Science and Technology School of Physics Science and Information TechnologyLiaocheng UniversityLiaocheng 252059China Department of Robotics and Automation Engineering PARK College of Engineering and TechnologyKaniyur 641659India School of Agriculture Science Liaocheng UniversityLiaocheng 252059China Liaocheng People's Hospital Medical College of Liaocheng UniversityLiaocheng 252000China Department of Electronics and Communication Engineering Indian Institute of Technology-RoorkeeRoorkee 247667India Department of Electrical and Electronics&Communication Engineering DIT UniversityDehradim 248009India

The ascorbic acid(AA)is a biomarker that can be used to detect the symptoms of severe disorders such as scurvy,Parkinson’s,Alzheimer’s,and cardiovascular *** this work,a simple and effective sensor model is developed to diagnose the presence of AA *** develop the sensor,a tapered single-mode optical fiber has been used with the well-known phenomenon of localized surface plasmon resonance(LSPR).For LSPR,the tapered region is immobilized with synthesized gold nanoparticles(AuNPs)and zinc oxide nanoparticles(ZnO-NPs)whose absorbance peak wavelengths appear at 519nm and 370nm,*** the basis of nanoparticles(NPs)configurations,two different biosensor probes are *** the first one,the sensing region is immobilized with AuNPs and named Probe *** the second probe,the immobilized layer of AuNPs is further coated with a layer of ZnO-NPs,and a resultant probe is termed as Probe *** characterizations of synthesized AuNPs and developed fiber probes are done by the ultraviolet-visible(UV-vis)spectrophotometer,high-resolution transmission electron microscope(HR-TEM),atomic force microscopy(AFM),and scanning electron microscope(SEM).To enhance the selectivity,a sensing region of probes is functionalized with ascorbate oxidase enzyme that oxidizes the AA in the presence of *** response of developed sensor probes is authenticated by sensing the samples of AA in the range from 500 nM to 1 mM,which covers the range of AA found in human bodies,i.e.,40μM-120μ*** performance analysis of the developed sensor probes has been done in terms of their stability,reproducibility,reusability,and *** observe the stability of AA,a pH-test has also been done that results in a better solubility of AA molecules in phosphate-buffered saline(PBS)solution.

关键词： Ascorbic acid localized surface plasmon resonance gold nanoparticlcs zinc oxide nanoparticles tapered fiber optical fiber sensor

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Adsorption of Chromium (VI) Using Nano-ZnO Doped Scrap Tire-Derived Activated Carbon

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Journal of Geoscience and Environment Protection 2022年第9期10卷 121-135页

作者： Jean Tsitsi Chigova Stanford Mudono Department of Chemical Engineering Faculty of Engineering National University of Science and Technology (NUST) Bulawayo Zimbabwe

Nowadays, nano mineral modified biochars show a promising adsorption capacity for pollutants removals by combining the advantages of porous structure of biochar and unique property of nano minerals. In this work, nano-zinc oxide doped scrap tire derived activated carbon (nZnO-STAC) was synthesized by wetness impregnation method. Equilibrium data were analyzed using Langmuir and Freundlich isotherm models while the kinetics of the process were examined using Lagergren Pseudo-first and second order, intraparticle diffusion and Elovich kinetic models. Characterization of the activated carbon by Powder X-ray Diffraction (PXRD). The surface groups present on the activated carbon surface were determined using the Fourier Transform Infra-Red Spectroscopy (FTIR) analysis. Optimization studies were carried out to determine the effects of pH, initial metal concentration, adsorbent dosage, contact time and adsorbent particle size on the Cr (VI) removal efficiency. The results showed optimum Cr (VI) removal at pH 3, 10 mg/L concentration, 120 minutes of contact using 1000 - 1400 μm adsorbent particle size at a dosage of 2.5 g/L. The adsorbent structure was found to be predominantly amorphous. The chromium removal efficiency of the adsorbent was around 81.6%. Of the tested kinetic models, the pseudo-second order model exhibited the best fit with the experimental data with an R2 value of 0.9744. This study clearly demonstrates the feasibility of using the nano-ZnO doped scrap tyre derived activated carbon adsorbent for the remediation of chromium (VI) polluted industrial wastewaters.

关键词： Adsorption zinc oxide nanoparticles Tire Granules Hexavalent Chromium Tannery Effluent

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Phenotype,Physiology,and Gene Expression of Barley Seedlings in Response to Nano zinc oxide Stress

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Phyton-International Journal of Experimental Botany 2021年第6期90卷 1589-1598页

作者： Mengyuan Dong Rong Sun Qianhui Yang Lantian Zhang Yangying Yong Yunxia Fang Xian Zhang Xiaoqin Zhang Dawei Xue College of Life and Environmental Sciences Hangzhou Normal UniversityHangzhou310036China

In recent years,zinc oxide nanoparticles(ZnO NPs)have been widely used as zinc fertilizers and *** use of ZnO NPs in this way can provide benefits to humans,but also has potential *** NPs inevitably enter the environment during their production and use,which affects the ecological environment and crop *** order to investigate the phenotype,physiology,and gene expression of barley(Hordeum vulgare L.)seedlings under ZnO NPs stress,the barely cultivars ZJU3(P21),Golden Promise(GP)and L23 were chosen for *** ZnO NPs concentrations were applied to compare the physiological and biochemical indexes of the barley seedlings and the responses of six stress-related genes,when seedlings were cultured to the two-leaf stage through *** results showed that the density of brown spots on the leaf surface increased with increasing ZnO NPs *** NPs stress inhibited the root growth of barley seedlings,and P21 was the most ***,ZnO NPs stress could stimulate plants to produce a large number of reactive oxygen species(ROS),resulting in an imbalance between the production and removal of ROS and membrane lipid peroxidation in *** imbalance inhibited the growth and development of the barley *** increasing ZnO NPs concentration,the activity of superoxide dismutase was gradually increased,the activity of catalase was progressively decreased,and the contents of malondialdehyde and proline were *** with the control,among six stress-related genes,the expression levels of five genes were downregulated and one gene was upregulated in the experimental *** study preliminarily revealed the toxic effect of ZnO NPs on seedlings and the effect on the expression of stress-related resistance genes in different barley varieties.

关键词： Antioxidant enzymes barley seedlings reactive oxygen species gene expression zinc oxide nanoparticles

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