Oxygen-deficient State Research Articles

Functional co-delivery nanoliposomes based on improving hypoxia for increasing photoimmunotherapy efficacy of cold tumors

Cold tumors lack T cells infiltration and have low immunogenicity, resulting insufficient immunotherapy response. Therefore, how to realize the transformation from cold tumor to hot tumor is an urgent problem to be solved. Photodynamic therapy can induce immunogenic death of tumor cells (ICD) and activate T lymphocytes to produce tumor immune response. However, hypoxia in the cold tumor microenvironment limits the effectiveness of photodynamic therapy. So in this article, MET-HMME/CAT-HMME@Nlip as a functional co-delivery nanoliposomes was constructed based on overcoming the above problems. Firstly, the oxygen-deficient state could be improved by the following two ways, one is catalase loaded in CAT-HMME@Nlip can decompose high concentration hydrogen peroxide to produce oxygen, and the other is metformin loaded in MET-HMME@Nlip can decrease oxygen consumption by inhibiting of mitochondrial respiration. And then with the increase of substrate oxygen concentration, the sensitivity of photodynamic therapy can be greatly improved and the anti-tumor immune response by PDT-induced ICD can also be enhanced obviously. In addition, metformin could act as a small molecule immune checkpoint inhibitor to reduce the expression of PD-L1 on the surface of tumor cells, thereby effectively improving the specific killing ability of cytotoxic T cells to tumor cells which could not only erasing the primary tumor, but also inhibiting the growth of simulated distant tumors through the immune memory function. This study provides a new idea for improving the clinical treatment effect of hypoxic cold tumors, especially for tumors that could not benefit from immunotherapy due to low or no expression of PD-L1 protein on the surface of tumor cells.

High dissolved oxygen regulation by side-stream supersaturated oxygenation impedes black-odor removal from rivers affected by combined sewer overflows

In rivers affected by combined sewer overflows (CSOs), achieving fine-grained management of dissolved oxygen (DO) regulation is critical for effective suppression of black odor after rainfall and reduction of river management costs. However, systematic investigations of the DO regulation mechanisms underlying the removal of key pollutants that cause black, odorous waters after CSOs are lacking. In this study, we investigated the effects of different DO regulation levels associated with short- and long-term side-stream supersaturated (SSS) oxygenation on the formation of carbon, nitrogen, sulfur, and other black odorous pollutants after CSOs. In addition, the effects of different DO levels regulated by SSS oxygenation were determined using the modified entropy weight method. The results showed that the number of CSOs, the rate of the black-odor phenomenon (12 h), and its extent increased. After different SSS oxygenation steps, the odorous degree of CSOs was reduced to varying extents. Additionally, for SSS oxygenation-mediated DO regulation to yield a DO ≥ 3.0 mg L−1, the oxygen-deficient reduction state of the interface between the overlying water and CSO-induced turbid water was effectively reversed. The removal rates of sulfide, Fe2+, and other black odorous substances varied; high levels of SSS oxygenation-mediated DO regulation were more conducive to the emergency improvement of redox conditions (182.67%) and removal of NH3–N (0.616–0.638 mg L−1·d−1). However, regulation of such high DO levels was not as effective for the long-term removal of black malodorous substances, leading to a rapid decline in pH (lowest decrease to 5.68) and denitrification efficiency in later stages. Additionally, evaluating the effectiveness of different SSS oxygenations provided further evidence that medium to high DO levels (4.5 mg L−1) achieved the highest comprehensive scores of 23.81 and had the optimal cost-effectiveness for long-term regulation. These results provide a scientific basis for improving the management of black odorous water in rivers after CSOs.

Change in parameters of the microcirculatory tissue system of the peri implant zone in patients with peri implantitis during complex use of mesodiencephalic modulation and ozone therapy

Abstract. Purpose of the study: The article examines the role of microcirculation disorders in the pathogenesis of peri-implantitis in patients after dental implantation. Materials and methods. It is shown that the development of peri-implantitis is characterized by significant changes in the parameters of microhemodynamics and oxygen exchange in the tissue involved in the inflammatory process. The state of oxygen and energy deficiency prompts the progression of inflammatory changes with the formation of signs of tissue destruction around dental implants. The application of a standard scheme of peri-implantitis therapy is accompanied by a correction of the microcirculatory tissue system indicators. The supplementation of standard treatment with course use of medical physical factors promotes the strengthening of the positive dynamics of microcirculation parameters of the peri-implant zone. The corrective influence of MDM-therapy is connected with the activation of the mechanisms of neuroendocrine regulation of vegetative functions, while the basis of ozone therapy is the polymodality of the factor, including the relaxation of the precapillary blood flow, improvement of the rheological properties of the blood, and the stimulating effect on angiogenesis processes. Results. The complex application of medical physical factors, combining systemotropic and local impacts, different modalities and points of application of their corrective activity, contributes to the manifestation of functional potentiation with a maximal corrective effect.

Defect characteristic of oxygen-deficient Ge-doped preform using photoluminescence spectroscopy

Study has been made of the Photoluminescence properties of Ge-doped silica preforms fabricated using the MCVD process and subsequently subjected to γ-ray irradiation. The photoluminescence emissions pointed to the presence of defects related to oxygen vacancies. Two types of preform were fabricated, obtained using a different flow rate and deposition temperature for each case. Results from the absorption spectra of the samples named as P1 and P2, show a signature absorption peak at 5.1 eV and 6.8 eV, indicative of oxygen-deficient and oxygen-rich defects respectively. Photoluminescence investigation have been carried out before and after the irradiation process with both samples reveal two main peaks at 1.5 eV. The highest intensity at 1.5 eV is known as an interaction between the Non- Bridging Oxygen Hole Centre (NBHOC) with the presence of impurity in the glass matrix. Upon irradiation, weak peak can be observed at 1.8 eV, sample P1 and P2, the PL intensity increases by a factor of 20 × and 50 × , respectively. This peak is associated with the oxygen deficient state in the sample. The peak referring to defect known as Germanium Lone Pair Centre (GLPC) are observed in both samples, peak shown at 3.1 eV, regardless of the Germanium Oxygen Deficient Centre (GODC) content. In regard to this, it can be concluded that this defect is generated independently in all germanium samples and are not correlated with the GODC band observed in the absorption band.

ZnO-NiO composite nanostructures produced by atmospheric PLD

In this study, ZnO-NiO binary metal oxides were synthesized by pulsed laser deposition regarding applications as gas sensors. The technology was applied in air at atmospheric pressure. A compound target fabricated by partially covering a ZnO pellet by a Ni slice was used for ablation. The structure, morphology, composition, and optical properties of the as deposited samples were studied. It was found that composites consisting of ZnO and NiO were formed during the ablation process in air. Generally, the morphology of the as deposited specimens represented a highly porous nanostructure. The samples’ microstructure indicated that the nanostructures were formed by spherically-shaped crystalline ZnO and NiO nanoparticles. The results demonstrated that the ZnO-NiO fabricated samples possessed a high surface-to-volume ratio with considerable number of components attributed to oxygen-deficient states and to adsorbed species, which makes them suitable for gas-sensing applications.

Green one-step synthesis of boron and nitrogen co-doped carbon dots based on inner filter effect as fluorescent nanosensors for determination of Fe3+

Significant efforts need to be devoted to enhancing the photoluminescence quantum yields (PLQY) of carbon dots (CDs) due to the typically low PLQY (< 10%) of currently synthesized CDs. Moreover, certain special industries such as textiles, paper, and food all have high requirements for water since Fe3+ can affect its color, odor, and taste. The traditional detection methods require expensive equipment, so a facile method to detect Fe3+ is urgently needed. In this work, the self-doping of nitrogen (N-CDs) has been achieved through tea residues as the carbon source to inhibit the oxygen-deficient state, and the doping of boric acid (BN-CDs) can activate the electron transition at the carbon site, which effectively enhanced the PLQY of CDs from 11.4% to 25.79% compared to N-CDs. Furthermore, as hydroxylated polyphenols in tea residues can adsorb metal ions, stable non-fluorescent matrix state complexes have been established between BN-CDs and Fe3+ to quench the FL owing to the inner filter effect. The linear relationship was formed in the concentration range of 0–60 μM, and the detection limit reached 0.07 μM. It demonstrates that along with the effective treatment of waste tea residues, the synthesized high fluorescence property BN-CDs are suitable to detect Fe3+ in water for textiles, paper, food, and other special industries.

Establishing Substoichiometric Ag Oxidation and Its Physicochemical, Optoelectrical, and Structural Consequences for Ag Electrodes

Oxidation is adversely associated with inducing catastrophic degradation of the electrical and optical properties of Ag film electrodes. Existing information is largely distributed across thermodynamically favorable, stoichiometric, and higher oxidation states. However, this information is elusive in affording a better understanding of substoichiometric oxidation in extremely oxygen-deficient states because conventional perspectives disregard the plausibility of substoichiometric oxidation. This study presents computational and experimental evidence for the implementation of substoichiometric Ag oxidation with unique physicochemical properties that are clearly discordant with those of the stoichiometric and higher oxidation states. Further, characterization results confirmed the favorable contribution of extreme substoichiometric oxidation to morphological/structural improvements by hindering the oxidation-induced optoelectrical degradations of Ag film electrodes. The unexpected outcomes of substoichiometric oxidation can be attributed to the spontaneous reduction of the oxide phases under ambient atmosphere conditions at 20 °C and 40% relative humidity, owing to their thermodynamic instabilities, while successfully implementing the oxidation-mediated, two-dimensional growth of Ag films. These findings provide a comprehensive understanding beyond the conventional conclusions drawn from stoichiometric and higher oxide phases. Therefore, the precise control of substoichiometric oxidation facilitates the preparation of highly efficient Ag electrodes by successfully implementing ultralow optoelectrical losses and structural deficiencies for Ag films simultaneously.

Optimized Lithography-Free Fabrication of Sub-100 nm Nb2O5 Nanotube Films as Negative Supercapacitor Electrodes: Tuned Oxygen Vacancies and Cationic Intercalation.

The direct growth of sub-100 nm thin-film metal oxides has witnessed a sustained interest as a superlative approach for the fabrication of smart energy storage platforms. Herein, sub-100 nm Zr-doped orthorhombic Nb2O5 nanotube films are synthesized directly on the Nb-Zr substrate and tested as negative supercapacitor electrode materials. To boost the pseudocapacitive performance of the fabricated films, supplement Nb4+ active sites (defects) are subtly induced into the metal oxide lattice, resulting in 13% improvement in the diffusion current at 100 m V/s over that of the defect-free counterpart. The defective sub-100 nm film (H-NbZr) exhibits areal and volumetric capacitances of 6.8 mF/cm2 and 758.3 F/cm3, respectively. The presence of oxygen-deficient states enhances the intrinsic conductivity of the thin film, resulting in a reduction in the band gap energy from 3.25 to 2.5 eV. The assembled supercapacitor device made of nitrogen-doped activated carbon (N-AC) and H-NbZr (N-AC//H-NbZr) is able to retain 93, 83, 78, and 66% of its first cycle capacitance after 1000, 2000, 3000, and 4500 successive charge/discharge cycles, respectively. An eminent energy record of approximately 0.77 μW h/cm2 at a power of 0.9 mW/cm2 is achieved at 1 mA/cm2 with superb capability.

Synthesis, Characterization, and In V ivo Toxicological Evaluation of Copper (II) Oxide Containing Herbometallic Siddha Nanocomplex "Thamira Parpam".

“Thamira parpam” (TP), a copper-based herbometallic oxide (copper (II) oxide) nanodrug has been used in Siddha medicine for centuries because of its anti-ulcerogenic property. However, the physicochemical properties and in vivo toxicity of TP still remain elusive. Rigorous clinical translation requires deciphering these vital properties. We have synthesized TP following a gold standard protocol in the traditional Siddha methodology. We assessed the size, phase, elemental constituents, and thermal stability of TP by SEM and TEM, XRD, EPR, and EDAX analyses, respectively. The results depicted the conversion of metallic copper into copper (II) oxide in the final stages of TP preparation and exhibited nanodimensions ranging between 10 and 50 nm. The XPS spectra revealed the presence of oxygen-deficient state and a carbonaceous coating was found on the surface of TP using TEM analysis. In vivo safety was studied in rat toxicity models by adopting OECD guidelines. Body weight changes, feed, and water intake were unaltered upon TP administration. Hematological, biochemical profiling, and histopathological findings also suggested its nontoxic nature with no abnormalities in major organs and its functions. Interestingly, we found that the metal toxicity could have been subdued because of the carbonaceous coating around the nanoparticle copper (II) oxide, confirming that the drug is safe at a low dose. Overall, our study has enlightened the safety of TP supporting the use of Siddha formulations.

Simultaneous Enhancement in Visible Transparency and Electrical Conductivity via the Physicochemical Alterations of Ultrathin-Silver-Film-Based Transparent Electrodes.

A methodology for the simultaneous modulation of the chemical and physical states of an amorphous TiOx layer surface and its impact on the subsequent deposition of a polycrystalline Ag layer are presented. The smoothened TiOx layer surface comprising chemically altered, oxygen-deficient states serves as a nucleating platform for Ag deposition, facilitating a marked increase (∼75%) in the nucleation number density, which strongly enhances the wettability of ultrathin Ag layers. The physically smoothened TiOx/Ag interface further reduces the optical and electrical losses. When the proposed methodology is applied to TiOx/Ag/ZnO transparent conductive electrodes (TCEs), exceptional TCE properties are yielded owing to the simultaneous improvement in visible transparency and electrical conductivity; specifically, a record-high 0.22 Ω-1 Haacke figure of merit is realized. TCEs are prepared on flexible substrates to verify their applicability as stand-alone flexible transparent heaters and as integrated heaters within electrochromic devices to enhance color-switching reactions.

Pathomorphological changes due to helium inhalation: an expert case report

BACKGROUND: Helium, being an inert substance, does not have a significant effect on the human body, but sometimes at very high concentrations in the air, it can cause suffocation and a state of oxygen deficiency. Oxygen-helium therapy has proven to be the most effective recovery, rehabilitation, and treatment for all types of lung damage and reduced saturation. It is even included in the recommendations for preventing, diagnosing, and treating COVID-19.&#x0D; Deaths due to inhalation of inert gases, especially helium, are sporadic in forensic practice. As a rule, the probability of death in such cases is most often associated with man-made accidents or violations of safety regulations when performing technological processes and operations related to the use of gas.&#x0D; Safety instructions for handling helium warn of possible damage to the mucous membrane of the eyes and frostbite of the skin, as well as mechanical injury when a heavy gas cylinder falls.&#x0D; CASE PRESENTATION: Inert gases do not interact with other chemicals. However, we encountered a suicide case where an inert gas was chosen as a means. Inhalation of helium caused macro- and micromorphological changes in the human body, which led to a fatal outcome.&#x0D; The case is illustrated by photographs of microscopic preparations, which demonstrate the absence of specific signs of toxic effects on the organs and tissues of the deceased.&#x0D; CONCLUSION: Despite the substances extreme volatility, the compressed gass pressure and low temperature can cause various injuries and even death. The study of general pathomorphology can be helpful in the conduct of a forensic medical examination.

액체질소에 의한 산소결핍 질식사

Asphyxia typically occurs due to oxygen deficiency in confined spaces. A male researcher died in a minor car accident. He had loaded a container filled with liquid nitrogen in his car the day before the accident. Clinical analysis of blood showed that blood alcohol concentration(BAC), carboxyhemoglobin (CO-Hb), drugs and toxins were negative. During the car investigation, it was found that there was frost around the lid of the liquid nitrogen container with a trace amount of liquid nitrogen left. To determine the cause of death, the simulation test was performed by reconstructing the situation of liquid nitrogen leaking in a confined space. The results showed that liquid nitrogen in the container was continuously evaporated and reduced the oxygen concentration in the car. After 20 min the state of oxygen deficiency was reached and then the oxygen concentration was cut down to 6.5 % within 10 hours. It was concluded that the cause of death was oxygen-deficient circumstance resulted from the evaporation of liquid nitrogen in the car. In order to determine the cause of death, it is necessary to perform a simulation test considering all potential factors that may affect the accident.

Oxygen releasing and antioxidant breathing cardiac patch delivering exosomes promotes heart repair after myocardial infarction

Constant oxygen supply is inevitable for cardiac tissue function and survival. Myocardial infarction (MI) leaves heart tissue in a state of oxygen deficiency, causing oxidative stress and irreversible death of cardiomyocytes. Although vital in treating MI, restoration of oxygen supply and attenuation of oxidative stress has not been successfully utilized as a therapeutic strategy. Herein, we developed and evaluated an oxygen releasing antioxidant nanofibrous bi-layered cardiac patch (PUAO-CPO-Collagen) supplemented with adipose derived stem cell exosomes (ADSC-EXO) to promote heart repair. Antioxidant polyurethane was synthesised and calcium peroxide (CPO) was incorporated as an oxygen releasing material. The bilayered cardiac patch consists of an oxygen releasing antioxidant polyurethane, electrospun over a porous collagen scaffold and supplemented with adipose derived stem cell exosomes. The patch demonstrated sustained release of oxygen and exosomes. Under in-vitro conditions, bilayered patch and ADSC exosomes illustrated proliferative, pro-angiogenic and pro-survival effect. In an in-vivo rat MI model, the bi-layered patch demonstrated enhanced cardiac function, reduced scar formation, significantly attenuating adverse cardiac remodelling through improved angiogenesis and decreased oxidative stress. Our study demonstrated an innovative and promising cell free biomaterial approach for delivering oxygen, promoting angiogenesis, and attenuating oxidative stress for enhanced heart regeneration after myocardial infarction.

Tumor microenvironment triggered local oxygen generation and photosensitizer release from manganese dioxide mineralized albumin-ICG nanocomplex to amplify photodynamic immunotherapy efficacy

Photodynamic therapy (PDT) has emerged as a potential clinical strategy for tumor therapy. It can generate reactive oxygen species (ROS) to cause the chemical damage of tumor cells and promote the immune killing effects of T cells on tumor cells in the presence of enough oxygen and PDT drugs. However, most solid tumors are in a state of oxygen deficiency, which seriously limit the efficacy of PDT in generation enough ROS. Besides, few safe PDT drugs with ideal pharmacokinetic behavior are available in the clinic, which severely limits the clinical transformation and application of PDT. Herein, we utilized manganese chloride to mineralize the hydrophilic indocyanine green/albumin polyplexes (ICG@BSA@MnO2) by using bio-mineralized method to solve these problems of PDT. These ICG@BSA@MnO2 nanoparticles could circulate in the blood for a long period other than quickly removed from body after 30 min like free ICG. When accumulated at the tumor site, ICG was responsively released in the presence of hydrogen peroxide. Apart this, the tumor hypoxia microenvironment was also reversed owing to enhanced O2 generation by the reaction of MnO2 with hydrogen peroxide. Benefits from the rich accumulation of ICG and ameliorated tumor hypoxia in the tumor sites, the enhanced generation of ROS could successfully promote the distribution of CD3+ and CD8+ T cells inside the tumors, which then lead to the amplified efficacy of PDT in both CT26 and B16F10 tumor models without causing any side effects.

Rational design and preparation of copper vanadate anchored on sulfur doped reduced graphene oxide nanocomposite for electrochemical sensing of antiandrogen drug nilutamide using flexible electrodes

Copper vanadate nanoparticles (Cu2V2O7) are synthesized by using a simple hydrothermal method and later anchored with sulfur-doped reduced graphene oxide (S-rGO) by using ultrasonication to form a hybrid nanocomposite. The synthesized composite underwent characterizations like X-ray diffraction analysis (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FT-IR), Dynamic ray scattering-Ultra violet–visible spectroscopy (DRS-UV–visible) and X-ray photoelectron spectroscopically revealed the triclinic pattern of the P 1̅ space group of α-Cu2V2O7 and the reduced oxygen deficiency state of metal centers (Cu+ or V4+) resulting with oxides of mixed-valence oxidative states and forming of Cu-O bond. Morphological analysis was carried out by using transmission electron microscopy (TEM) and Field emission scanning electron microscopy (FE-SEM) with elemental mapping and EDX analysis. Furthermore, a novel electrochemical sensor is prepared by using the hybrid sCu2V2O7/S-rGO nanocomposite on to a disposable screen-printed carbon paste electrode (SPCE) for electrochemical sensing of antiandrogen drug nilutamide (NLT). This report reveals excellent activity in determining NLT with a low detection limit of 0.00459 nM for the linear range of 0.001–15 μM with high sensitivity of 26.2605 µA µM−1 cm−2. Further, electrode performance showed appreciable performance in real-time monitoring of biological samples like human blood serum, urine samples.

Cooperative Jahn-Teller effect in NdMn1-xFexO3+δ (0 ≤ x ≤ 0.2)

NdMn1-xFexO2.90(5) (0 ≤ x ≤ 0.2) compounds undergo first order reversible orthorhombic-orthorhombic structural phase transition from a high temperature O phase to low temperature O′ phase after heat treatment in Ar. This transition takes place in wide temperature range between the Jahn Teller (JT) temperature TJT and the onset of transition to orbital ordered state at T∗. Iron shifts the transition to lower temperatures TJT = 1230(5) K, 1190(5) K, 1160(5) K and T∗ = 1035(5) K, 985(5) K, 950(5) K for x = 0; 0.1; and 0.2. Both O phase and O’ phase coexist in short temperature range above T∗ and cooperative Jahn Teller distortions (CJTDs) persist even in O phase for x = 0 and 0.1 in vicinity of T∗.Oxygen is being built into crystal lattice for heat treatment in air at elevated temperatures. As a consequence the composition changes to NdMn1-xFexO3, the CJTDs vanish from O phase. The increase of oxygen in samples results in the reduction of anomalies at the phase transition and their shift to lower temperatures (TJT = 1106(5) K and T∗ = 1045(5) K for x = 0). The transformation from O phase to O’ phase is not connected with strong anomaly anymore for x = 0.1 and 0.2. The CJTDs are present below 750 K on all samples, which are temperatures from about 350 K to 250 K smaller in comparison with Ar atmosphere. Subsequent thermal cycling in air leads to phase separation into two phases for compounds with higher concentration of iron.Analysis of our results revealed that the O to O′ phase transitions are much stronger for samples in oxygen deficient state where oxygen vacancy clusters can be created at relevant temperature. We suppose that oxygen vacancy clusters are responsible for appearance of strong anomalies at the O to O′ phase transition and for easier formation of CJTDs over the volume of samples. Conditions for formation of CJTDs as well number of JT active ions in the sample are main factors which affect the O to O’ phase transition.

Microwave assisted sol-gel synthesis of bioactive zirconia nanoparticles – Correlation of strength and structure

It is well known that long term stability in zirconia has been a problem because of the structural alteration from stabilized tetragonal zirconia to monoclinic that leads to fracture in implants. Microwave (MW) assisted sol-gel synthesis is employed in the present work to prepare stabilize zirconia nanoparticles. ZrOCl2.8H2O is used as a precursor whereas de-ionized water is used as a solvent. Power of microwave radiations is varied in the range of 100–1000W. Zirconia nanoparticles have been characterized under as-synthesized, 6- and 12-months’ room temperature (RT) aged conditions. Metastable phase (MP) of zirconia, appearing under as-synthesized conditions, transforms to phase pure tetragonal zirconia (t-ZrO2) after RT aging that was prepared with MW powers of 100, 200 and 700–1000W. Whereas, MP transforms to mixed tetragonal-monoclinic phases at microwave powers of 300–600W after RT aging. XPS results show presence of oxygen-deficient state of ZrO2 lattice along with surface defects contributing towards the tetragonal zirconia phase under all conditions. Value of dielectric constant (i.e. ~11–12 at log f = 4.0), hardness (~13 GPa) and fracture toughness observed under all conditions are well in agreement to be used for biological implants. Disks of aged t-ZrO2 nanoparticles are checked for their biodegradation test by dipping in simulated body fluid for several weeks. ZrO2, with 26 weeks of immersion, shows small loss in hardness and weight. Stabilized tetragonal zirconia shows strong anti-oxidant activity. Stabilized ZrO2 nanoparticles presented strong antibacterial activity against both gram positive (S. aureus, Bacillus) and gram negative (E. coli) bacteria. Thus, structural and mechanical stability of zirconia (checked after 6 and 12 months) make this material highly beneficial for long term use in biomedical applications.

Improvement of Electrical Performance by Neutron Irradiation Treatment on IGZO Thin Film Transistors

The effects of the neutron irradiation treatment on indium-gallium-zinc oxide (IGZO) are investigated as a function of the neutron irradiation time. With an increase in neutron irradiation time, the oxygen vacancies associated the oxygen deficient states increase, and both shallow and deep band edge states below the conduction band also increase. Moreover, the conduction band offset continuously decreases because of the increase in the oxygen vacancies with increasing the neutron irradiation time. In IGZO TFTs with the neutron irradiation time for 10 s, superior device performance demonstrates such as the lower threshold voltage, higher field effect mobility, smaller sub-threshold gate swing, larger on-off current ratio, and improved bias stability, comparing those of other IGZO TFTs.

Thermal plasma synthesis and electrochemical properties of high-voltage LiNi0.5Mn1.5O4 nanoparticles

The synthesis of LiNi0.5Mn1.5O4 has been reported to change the crystal structure with the oxygen partial pressure and affect the battery characteristics. LiNi0.5Mn1.5O4 involves the formation of impurities, such as LixNi1−xO, LixMn3−xO4, and Li2CO3, at a high temperature range exceeding 700 °C because oxygen loss occurs during synthesis. LiNi0.5Mn1.5O4 electrochemically contains Mn4+, however, Mn3+ is formed because of oxygen deficiency. The Li–Ni–Mn-oxide causes a disproportionation of Mn3+ in an oxygen-deficient state. The synthesized Li–Ni–Mn-oxide nanoparticles at 10,000 K by induction thermal plasma formed spinel-type LiNi0.5Mn1.5O4 (space group Fd3m) of Mn4+. The crystal structure of the cubic-spinel nanoparticles approached a LiNi0.5Mn1.5O4 single phase as the flow rate of O2 increased from 2.5 to 5 l min−1. The formation of LiNi0.5Mn1.5O4 was shown to be accelerated by increasing the O2 gas flow rate. The measured current–voltage characteristics of LiNi0.5Mn1.5O4 nanoparticles appeared at around 4.7–4.8 V as the reaction peak of Ni2+/Ni3+ and Ni3+/Ni4+. In contrast, the Mn of the Li–Ni–Mn-oxide nanoparticles synthesized in the oxygen-deficient state was less than trivalent, which caused disproportionation of Mn. The measured current-voltage characteristics showed peak of an oxygen desorption at near 4.6 V. This study investigated the factors affecting the crystal structure formation and electrochemical properties of high-voltage LiNi0.5Mn1.5O4 nanoparticles formed in thermal plasma.

All-oxide thin-film transistors with channels of mixed InOx-ZnOy formed by plasma-enhanced atomic layer deposition process

To make high mobility oxide thin-film transistors (TFTs) for transparent large displays, the authors fabricated all-oxide TFTs having amorphous mixed-oxide channels of indium oxide (InOx) and zinc oxide (ZnOy). Liquid precursors of 3-(dimethyl amino)propyl-dimethyl indium (C7H18InN) and diethyl zinc [(C2H5)2Zn] and oxygen plasma were used to form mixed-oxide channels by plasma-enhanced atomic layer deposition (ALD). The authors varied the cycle ratio of InOx and ZnOy to deduce the optimal ratio of InOx:ZnOy for high performance TFTs. X-ray photoelectron spectroscopy analyses were performed to reveal the decrease in the oxygen-deficient state as the fraction of InOx increases. At a deposition cycle ratio of InOx:ZnOy = 2:1, the TFT demonstrated the best performance of field effect mobility of 30.3 cm2/V s, subthreshold of 0.14 V/decade, and Ion/Ioff ratio of 3.1 × 109. By adjusting the relative cycles of different oxides in an ALD process, one may obtain the desired mixed-oxide channel TFT properties, which is not readily possible in the sputtering process. By varying the compositions of the oxide channel layer, the latitude of device fabrication could be widening, thereby enabling performance customization.