Study of deposition parameters for the fabrication of ZnO thin films using femtosecond laser

Femtosecond (fs) pulsed laser deposition (fs-PLD) of ZnO thin film on borosilicate glass substrates is reported in this work. The effect of important fs-PLD parameters such as target–substrate distance, laser pulse energy and substrate temperature on structure, morphology, optical transparency and luminescence of as-deposited films is discussed. XRD analysis reveals that all the films grown using the laser energy range 120–230 μJ are polycrystalline when they are deposited at room temperature in a ~10−5 Torr vacuum. Introducing 0.7 mTorr oxygen pressure, the films show preferred c-axis growth and transform into a single-crystal-like film when the substrate temperature is increased to 100 °C. The scanning electron micrographs show the presence of small nano-size grains at 25 °C, which grow in size to the regular hexagonal shape particles at 100 °C. Optical transmission of the ZnO film is found to increase with an increase in crystal quality. Maximum transmittance of 95 % in the wavelength range 400–1400 nm is achieved for films deposited at 100 °C employing a laser pulse energy of 180 μJ. The luminescence spectra show a strong UV emission band peaked at 377 nm close to the ZnO band gap. The shallow donor defects increase at higher pulse energies and higher substrate temperatures, which give rise to violet-blue luminescence. The results indicate that nano-crystalline ZnO thin films with high crystalline quality and optical transparency can be fabricated by using pulses from fs lasers

Effect of [OH-] linkages on luminescent properties of ZnO nanoparticles

Optical properties of ZnO nanoparticles prepared from a simple chemical method using sodium zincate bath show strong white light emission. X-ray absorption fine structure studies reveal a completely different local environment around Zn in these ZnO nanoparticles. The observed luminescence properties and local structural changes have been explained on the basis of a linkage between Zn and OH- ions in the surface layers of ZnO nanoparticles.Comment: J. Phys. Chem. C. (2011) (in print

Development of 2-in-1 Sensors for the Safety Assessment of Lithium-Ion Batteries via Early Detection of Vapors Produced by Electrolyte Solvents

Batteries play a critical role in achieving zero-emission goals and in the transition toward a more circular economy. Ensuring battery safety is a top priority for manufacturers and consumers alike, and hence is an active topic of research. Metal-oxide nanostructures have unique properties that make them highly promising for gas sensing in battery safety applications. In this study, we investigate the gas-sensing capabilities of semiconducting metal oxides for detecting vapors produced by common battery components, such as solvents, salts, or their degassing products. Our main objective is to develop sensors capable of early detection of common vapors produced by malfunctioning batteries to prevent explosions and further safety hazards. Typical electrolyte components and degassing products for the Li-ion, Li–S, or solid-state batteries that were investigated in this study include 1,3-dioxololane (C₃H₆O₂─DOL), 1,2-dimethoxyethane (C₄H₁0O₂─DME), ethylene carbonate (C₃H₄O₃─EC), dimethyl carbonate (C₄H₁0O₂─DMC), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium nitrate (LiNO₃) salts in a mixture of DOL and DME, lithium hexafluorophosphate (LiPF₆), nitrogen dioxide (NO₂), and phosphorous pentafluoride (PF₅). Our sensing platform was based on ternary and binary heterostructures consisting of TiO₂(111)/CuO(1̅11)/Cu₂O(111) and CuO(1̅11)/Cu₂O(111), respectively, with various CuO layer thicknesses (10, 30, and 50 nm). We have analyzed these structures using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), micro-Raman spectroscopy, and ultraviolet–visible (UV–vis) spectroscopy. We found that the sensors reliably detected DME C₄H₁0O₂ vapors up to a concentration of 1000 ppm with a gas response of 136%, and concentrations as low as 1, 5, and 10 ppm with response values of approximately 7, 23, and 30%, respectively. Our devices can serve as 2-in-1 sensors, functioning as a temperature sensor at low operating temperatures and as a gas sensor at temperatures above 200 °C. Density functional theory calculations were also employed to study the adsorption of the vapors produced by battery solvents or their degassing products, as well as water, to investigate the impact of humidity. PF₅ and C₄H₁0O₂ showed the most exothermic molecular interactions, which are consistent with our gas response investigations. Our results indicate that humidity does not impact the performance of the sensors, which is crucial for the early detection of thermal runaway under harsh conditions in Li-ion batteries. We show that our semiconducting metal-oxide sensors can detect the vapors produced by battery solvents and degassing products with high accuracy and can serve as high-performance battery safety sensors to prevent explosions in malfunctioning Li-ion batteries. Despite the fact that the sensors work independently of the type of battery, the work presented here is of particular interest for the monitoring of solid-state batteries, since DOL is a solvent typically used in this type of batteries

Structural, optical and magnetic properties of Ni-doped ZnO micro-rods grown by the spray pyrolysis method

Undoped and Ni-doped ZnO micro-rod arrays were successfully synthesized by the spray pyrolysis method on glass substrates. Analysis of the samples with x-ray diffraction and scanning electron microscopy showed that these micro-rod arrays had a polycrystalline wurtzite structure with a highly c-axis preferred orientation. Photoluminescence studies at both 300 K and 10 K show that the incorporation of nickel leads to a relative increase in the visible blue light band intensity. Magnetic measurements indicated that Ni-doped ZnO samples exhibit ferromagnetic behavior at room temperature, which is possibly related to the presence of point defects

Ultra-fast Microwave Synthesis of ZnO Nanowires and their Dynamic Response Toward Hydrogen Gas

Ultra-fast and large-quantity (grams) synthesis of one-dimensional ZnO nanowires has been carried out by a novel microwave-assisted method. High purity Zinc (Zn) metal was used as source material and placed on microwave absorber. The evaporation/oxidation process occurs under exposure to microwave in less than 100 s. Field effect scanning electron microscopy analysis reveals the formation of high aspect-ratio and high density ZnO nanowires with diameter ranging from 70 to 80 nm. Comprehensive structural analysis showed that these ZnO nanowires are single crystal in nature with excellent crystal quality. The gas sensor made of these ZnO nanowires exhibited excellent sensitivity, fast response, and good reproducibility. Furthermore, the method can be extended for the synthesis of other oxide nanowires that will be the building block of future nanoscale devices

Максаквин в лечении рецидивирующего урогенитального хламидиоза (клинико-лабораторное и электронно-микроскопическое исследование)

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Комплементингибирующая терапия атипичного гемолитико-уремического синдрома у пациентки с мутацией гена, кодирующего фактор Н

Atypical haemolytic uremic syndrome (aHUS) is an extremely rare pathology with the development of complement-mediated thrombotic microangiopathy (TMA). Before eculizumab, a humanized IgG monoclonal antibody to the complement component C5, the prognosis of total and renal survival with aHUS was unfavourable due to the high probability of death and the development of end-stage chronic renal failure in surviving patients. This article presents a clinical observation of a patient with aHUS who had an identified heterozygous factor H (CFH) mutation — c.3653G>A(p.Cys1218Tyr), and two heterozygous variants of polymorphism in the same gene — c.2016A>G; c.2808G>T. Despite the achievement of haematological remission of TMA against the background of plasma therapy, the child developed dialysis-dependent renal failure. Treatment with eculizumab in a patient with chronic kidney damage provided a significant improvement in their function, maintaining a stable remission and improving the quality of life of the patient with aHUS.Kh. М. Emirova, Е. S. Stolyarevich take part in educational events for doctors as lecturers with the support of Alexion Pharma. The other contributors confirmed the absence of a reportable conflict of interest.Атипичный гемолитико-уремический синдром (аГУС) — ультраредкая патология с развитием комплементопосредованной тромботической микроангиопатии (ТМА). До появления экулизумаба — гуманизированного моноклонального антитела класса IgG к C5-компоненту комплемента — прогноз общей и почечной выживаемости при аГУС был неблагоприятным вследствие высокой вероятности летального исхода и развития терминальной хронической почечной недостаточности у выживших пациентов. В этой статье представлено клиническое наблюдение пациентки с аГУС, у которой были идентифицированы гетерозиготная мутация гена, кодирующего фактор Н (CFH) — c.3653G>A(p.Cys1218Tyr) и два гетерозиготных варианта полиморфизма в том же гене — c.2016A>G; c.2808G>T. Несмотря на достижение гематологической ремиссии ТМА на фоне плазмотерапии, у ребенка развилась диализзависимая почечная недостаточность. Лечение экулизумабом при уже имеющемся хроническом повреждении почек обеспечило существенное улучшение их функции, поддержание стойкой ремиссии и повышение качества жизни пациентки с аГУС.Х.М. Эмирова, Е.С. Столяревич принимают участие в образовательных мероприятиях для врачей в качестве лекторов при поддержке компании «Алексион Фарма». Другие соавторы статьи подтвердили отсутствие конфликта интересов, о котором необходимо сообщить