Fluorine Ions Research Articles

Determination of adsorbable organic halogens in textiles by ultrasonic extraction-high temperature combustion absorption-ion chromatography

建立了一种对纺织品中可吸附有机卤化物(AOX)的超声提取-高温燃烧吸收-离子色谱定量检测分析新方法。该方法采用超声方式提取纺织品中的AOX,提取液加入活性炭进行振荡吸附,并用酸性硝酸钠溶液对无机卤化物进行去除。采用程序升温的氧化燃烧方式对吸附AOX的活性炭进行裂解、燃烧及气化,其产生的卤化氢等气体随载气进入吸收液并完全转化为无机卤素阴离子,采用离子色谱分离测定,外标法定量。实验优化了超声提取时间、活性炭用量、燃烧气及其流量、燃烧升温程序、吸收液和吸收方式等前处理条件,并对离子色谱的仪器分析条件如色谱柱、柱温及淋洗液流速等进行优化。结果表明,氟、氯、溴、碘4种卤素离子的标准溶液在0.02~10 mg/L范围内呈线性关系,线性相关系数(R2)均在0.999以上;AOX测定的方法定量限为0.10~0.50 mg/kg。以棉、毛和涤纶3种不同种类的阴性纺织样品作为样品基质,选取典型的有机卤化物进行加标,在低、中、高3个加标水平下测得AOX的平均回收率为82.3%~98.7%,相对标准偏差(RSD, n=7)为2.0%~5.7%,表明方法具有良好的回收率和精密度。将该方法应用于实际纺织样品的测定,检出了不同含量的AOX,且重复性好。研究建立的方法通过采用活性炭的振荡吸附、程序升温的高温氧化燃烧方式和多孔吸收瓶的二级吸收方法,提高了AOX转化为无机卤素的回收率;同时利用离子色谱仪器选择性好、灵敏度高的特点成功地一次性分离检测4种AOX,且无杂质离子的干扰。该方法简单、准确、可靠,满足国内外法规和标准对纺织品中AOX的限量要求,适用于纺织品中AOX的分析测定。

СРАВНИТЕЛЬНЫЙ АНАЛИЗ РЕЗУЛЬТАТОВ ЛОКАЛЬНОГО ПРИМЕНЕНИЯ РАЗЛИЧНЫХ ЛЕКАРСТВЕННЫХ ФОРМ МЕСТНЫХ ФТОРПРЕПАРАТОВ IN VITRO

The aim of this research was to study the effectiveness of different medicinal forms of the products for local fluorine prophylaxis in vitro. The object of study was the intact first premolars removed on orthodontic indications. The extracted teeth were kept in saline solution. Then the Flairesse line product (DMG, Germany) for local fluorine prophylaxis (on the producer's instruction) was applied onto the proximal surfaces. In all studied groups the depth of penetration into an enamel of ions of fluorine was recorded up to 20 мm. The difference in radiation levels is significant (p = 0.0125). Groups of teeth with a focus of subsurface demineralization formed under laboratory conditions, on the surface of which fluorine-containing preparations were applied (comparison groups), had statistically significantly higher concentrations of fluoride ions at a depth of 15 um than teeth with enamel caries in the stage of spots on the proximal surface, on which fluorine-containing preparations were applied (control) (p < 0.0125).

Study on Electrogalvanizing Technology and Chromium-Free Passivation Treatment of 08Al Plate

An environment-friendly electrogalvanizing technology of 08Al cold rolled steel sheet (CRS) was developed. 08Al CRS sheet was placed as cathode in the electroplating solution containing zinc salt 1-10g/L, organic acid 3-24g/L, complexing agent 0.2-0.8g/L, and Hot-dip galvanized alloyed sheet (GA) as anode. The relationship between the current density and the plating mass per unit area was studied by applying 0.15-2A direct current at room temperature, current density 0.19-2.6A/dm2, and plating time 35min. The relationship between plating mass per unit area and anode thinning per unit area was linear regression by introducing current density as intermediate quantity. The effect of electric power range on the coating mass per unit area was studied under the condition of different concentration of main salt. The chromium-free passivation treatment was also carried out on the surface of electrogalvanizing layer. 08Al electrogalvanized sheet and GA sheet were placed in chromium-free passivation solution containing molybdate 1-10g/L, hydrogen peroxide 1-5g/L, fluorine ion complexing agent 1-10g/L, potassium hydroxide 1-2g/L. The temperature and reaction time of chromium-free passivation solution and the corrosion resistance of chemical conversion film were studied, and the experimental conditions of chromium-free passivation were optimized. The adhesion and corrosion resistance of the coating were tested by scratching test and neutral salt spray test (NSS). The results show that after scratching test, the adhesion of the electrogalvanizing layer on 08Al surface reaches grade 0, and the adhesion of the electrogalvanizing and chemical conversion film composite coating on 08Al surface reaches grade 0. The NSS test showed that the corrosion resistance increased with the increase of the thickness of the galvanizing layer. The corrosion resistance time of the galvanizing layer with the thickness of 15um exceeded 216h. Salt spray resistance time of electric galvanizing layer about 10um is 72-96 h; The salt spray resistance time of electrogalvanizing layer less than 5um is less than 48 h. The salt spray corrosion time of GA plate (galvanized layer thickness is 10-11um) is less than 96 h. After chromium-free passivation treatment, the corrosion resistance of GA plate is more than doubled to 192h. The salt spray corrosion resistance of the composite coating (10-11um thickness) on 08Al with electrogalvanizing and chemical conversion film can reach more than 216h.

Muon sites in PbF2 and YF3 : Decohering environments and the role of anion Frenkel defects

Muons implanted into ionic fluorides often lead to a so-called F--$\ensuremath{\mu}$--F state, in which the time evolution of the muon spin contains information about the geometry and nature of the muon site. Nuclei more distant from the muon than the two nearest-neighbor fluorine ions result in decoherence of the F--$\ensuremath{\mu}$--F system, and this can yield additional quantitative information about the state of the muon. We demonstrate how this idea can be applied to the determination of muon sites within the ionic fluorides $\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{PbF}}_{2}$ and ${\mathrm{YF}}_{3}$, which contain fluoride ions in different crystallographic environments. Our results can be used to distinguish between different crystal phases and provide strong evidence for the existence of anion Frenkel defects in $\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{PbF}}_{2}$.

Recycling rare earth from ultrafine NdFeB waste by capturing fluorine ions in wastewater and preparing them into nano-scale neodynium oxyfluoride

Ultrafine NdFeB waste is a relatively clean waste produced during NdFeB magnet processing. Fluorine-containing wastewater is a common type of industrial wastewater, such as stainless steel pickling wastewater. In this work, rare earth element neodynium was recycled from ultrafine NdFeB waste by capturing fluorine ions in the fluorine-containing wastewater and prepared into neodynium oxyfluoride. The reaction process was investigated through UV-Vis-NIR, thermogravimetry/differential thermogravimetry (TG/DTG), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The neodymium hydroxide in the ultrafine NdFeB waste reacted with fluorine ions to form Nd(OH)2F, and Nd(OH)2F was then transformed into neodymium oxyfluoride after decomposition. The formed neodymium oxyfluoride is found to be particles with rhombohedral structure and a particle size of around 50 nm. The reaction kinetics of forming Nd(OH)2F was investigated. The reaction kinetic equation was established and the reaction activation energy was calculated. The effect of fluorine ion concentration on the reaction rate and products was evaluated. The results show that the reaction rate increases with the increase of fluorine ion concentration in the range of 0.01–1.5 mol/L, but it has little effect. In addition, the fluorine ion concentration affects the crystallinity of formed neodymium oxyfluoride. The recycling process not only realizes the sustainable utilization of rare earths, but also reduces the concentration of fluorine ions in the fluorine-containing wastewater, achieving two goals with one stone.

Hierarchical Stratiform of a Fluorine-Doped NiO Prism as an Enhanced Anode for Lithium-Ion Storage.

Doping is regarded as a prominent strategy to optimize the crystal structure and composition of battery materials to withstand the anisotropic expansion induced by the repeated insertion and extraction of guest ions. The well-known knowledge and experience obtained from doping engineering predominate in cathode materials but have not been fully explored for anodes yet. Here, we propose the practical doping of fluorine ions into the host lattice of nickel oxide to unveil the correlation between the crystal structure and electrochemical properties. Multiple ion transmission pathways are created by the orderly two-dimensional nanosheets, and thus the stress/strain can be significantly relieved with trace fluorine doping, ensuring the mechanical integrity of the active particle and superior electrochemical properties. Density functional theory calculations manifest that the F doping in NiO could improve crystal structural stability, modulate the charge distribution, and enhance the conductivity, which promotes the performance of lithium-ion storage.

Retraction Note to: Characteristics of heavy metal pollutants in groundwater based on fuzzy decision making and the effect of aerobic exercise on teenagers

Due to its abundant reserves and pure water quality, groundwater is an important water resource on the earth, which is widely distributed and easy to use, so it is widely used in industrial production, agricultural production, and domestic drinking. Most urban and rural areas in China use groundwater as drinking water source, and the quality of groundwater is closely related to the life of residents. Indiscriminate use of agricultural fertilizers, wanton discharge of industrial wastewater, and untreated wastewater will cause heavy metal pollution in groundwater. Groundwater is polluted by characteristic pollutants, which makes it difficult to deal with, and the deeper the water layer is, the lower the self-purification capacity will be, threatening the health of residents. In this paper, the groundwater samples of 58 towns in l area were collected as the investigation area, and the contents of fluorine ion and 16 kinds of metals and nonmetals were analyzed and discussed by ICP-MS and other equipment, as well as the characteristics of rural groundwater pollution in dry period. At the same time, the index model fuzzy decision making and single factor of health risk assessment model were used to evaluate the carcinogenic and non-carcinogenic risk. Obesity among Chinese adolescents is also a very worrying problem. The current literature supports many weight loss methods. Exercise weight loss can not only reduce fat, but also improve physical strength. In the long run, it can make us gain synergy. In life, people are aware of the impact of aerobic exercise on weight loss, so they rarely use high-intensity temporary strength for training. According to the research of fuzzy decision making, it is applied to groundwater and aerobic movement, so that it can be effectively improved.

Multi-ion-doped nano-hydroxyapatite-coated titanium intramedullary pins for long bone fracture repair in dogs-Clinical evaluation.

Plasma spray nano-hydroxyapatite-coated titanium intramedullary implants doped either with 5% zinc, 2.5% strontium, and 2.5% fluorine ions or with 5% zinc, 5% strontium, and 2.5% silver ions were evaluated compared with plasma spray nano-hydroxyapatite-coated titanium intramedullary implant and uncoated titanium intramedullary implants for open reduction and internal immobilization in 24 clinical cases of long bone fracture repair in dogs. Fracture-healing limb outcome was evaluated clinically, that is, radiographically. Biochemical estimation of serum calcium, serum phosphorus, alkaline phosphatase (ALP), and bone markers (bone ALP [BALP] and C-telopeptide of type 1 collagen [CTX]) was carried out on 0th day, 3rd week, 6th, and 9th week postoperatively. Multi-ion-doped plasma spray nano-hydroxyapatite-coated titanium intramedullary implants were found to be superior to plasma spray nano-hydroxyapatite-coated titanium intramedullary implants and uncoated titanium intramedullary implants in terms of all the parameters studied. Using plasma spray nano-hydroxyapatite-coated titanium implants doped with multi ions, that is, 5% zinc, 5% strontium, and 2.5% silver gave the best results in fracture repair followed by the implants doped with 5% zinc, 2.5% strontium, and 2.5% fluorine ions. Earliest and excellent limb usage with no postoperative complications was the hallmark of the use of these multi-ion-doped implants with higher serum calcium, serum phosphorus, ALP, BALP, and CTX values up to 3rd postoperative week and no lameness on the 21st day.

Effect of Fluoride Ion on the Separation of Fluorite from Calcite Using Flotation with Acidified Water Glass

As a common depressant, acidified water glass (AWG) has strong inhibitory effects on fluorite and calcite. The inhibited fluorite is difficult to be recovered, thus resulting in the waste of resources and low flotation efficiency. In this study, the interaction of fluoride ions with fluorite and calcite surfaces was investigated, and its effects of AWG adsorption on mineral surfaces were evaluated. Micro-flotation experiments indicated that the flotation recovery of fluorite is 88.72% after fluoride ion treatment, that is, approximately fourfold with respect to that without fluoride ion modification. The results of solution chemical calculations showed that SiO(OH)3− is the main component to inhibit fluorite, and Si(OH)4 is the main component to inhibit calcite in AWG solution. XPS and ICP-MS results showed that fluoride ions can improve the floatability of fluorite by converting CaSiO3 on the surface of fluorite into CaF2, but the conversion ability of Si(OH)4 on the surface of calcite is weak, which increases the difference in floatability between fluorite and calcite. The above results were further verified by the analysis of flotation foam image and contact angle measurement. After fluorine ion treatment, the contact angle of fluorite increased, and it was more easily adsorbed on the foam. Therefore, the interaction of the fluoride ion with the fluorite surfaces eliminated the adsorption of AWG on fluorite, thereby resulting in the enhanced hydrophobicity of fluorite. Different from the traditional metal ions modification, the idea of anion modification in this paper is expected to be further studied.

Toward Better Stability and Reversibility of the Mn4+/Mn2+ Double Redox Activity in Disordered Rocksalt Oxyfluoride Cathode Materials

Cation-disordered rocksalt (DRS) materials have shown good initial reversibility and facile Li+ insertion and extraction in the structure at high rates. However, all of the Li-rich oxyfluorides introduced so far suffer from short cycle lifetimes and severe capacity fading. In the current study, we combine the strategy of using high-valent cations with partial substitution of oxygen anions by fluorine ions to achieve the optimal Mn4+/Mn2+ double redox reaction in the composition system Li2Mn1–xTixO2F (0 ≤ x ≤ 2/3). While Ti-rich compositions correlate to an O-oxidation plateau and a partial Mn3+–Mn4+ redox process at high voltages, owing to the presence of Ti3+ in the structure, a new composition Li2Mn2/3Ti1/3O2F with a lower amount of Ti shows better electrochemical performance with an initial high discharge capacity of 227 mAh g–1 (1.5–4.3 V window) and a Coulombic efficiency of 82% after 200 cycles with a capacity of 136 mAh g–1 (>462 Wh kg–1). The structural characteristics, oxidation states, and charge-transfer mechanism have been examined as a function of composition and state of charge. The results indicate a double redox mechanism of Mn4+/Mn2+ in agreement with Mn–Ti structural charge compensation. The findings point to a way for designing high-capacity DRS materials with multi-electron redox reactions.

Stability of the threshold voltage in fluorine-implanted normally-off AlN/GaN HEMTs co-integrated with commercial normally-on GaN HEMT technology

Fluorine ion migration in normally-off AlN/GaN HEMTs fabricated by fluorine ion plasma implantation technology is evidenced. Devices under test are co-integrated into the OMMIC commercial D006GH/D01GH MMIC process, providing fluorine-free normally-on HEMTs. Gate reverse bias step-stress experiment at a drain fixed voltage of 0 V, carried out as well on normally-on ones as on normally-off ones, shows a permanent negative shift in the threshold voltage Vth of normally-off devices only. Vth degradation is starting at a VGS,stress of −8 V, with a negative shift from 0 V to −0.4 V at VGS,stress = −30 V, while the transconductance gm and gm,max remains unchanged prior to breakdown that occurred at VGS,stress ranging between −26 and −32 V. Since the positive threshold voltage of these devices is induced by F-ions dose and position, the above result suggests a possible drift of F-ions away from the 2DEG channel. A field-assisted migration mechanism of fluorine ions is proposed and supported by the absence of Vth degradation in fluorine-free normally-on devices.

Kinetic and Thermodynamic Characteristics of Fluoride Ions Adsorption from Solution onto the Aluminum Oxide Nanolayer of a Bacterial Cellulose-Based Composite Material.

The described research examined the adsorption of fluoride ions from solution immobilized onto an aluminum oxide-coated bacterial cellulose-based composite material in which aluminum oxide had been deposited using ALD technology. The kinetic regularities of the adsorption of fluoride ions from the solution as well as the mechanism of the processes were analyzed. The established equations show that the dynamics of adsorption correspond to first-order kinetics. Based on the Langmuir adsorption isotherms, we defined the adsorption equilibrium constants, parameter maximum adsorption, and change in Gibbs free energy. It is shown that, with increasing temperature, an increase in the reaction rate is constant, both forward and reverse. This testifies to the activated character of adsorption of the first fluoride on the surface of the sorbent based on bacterial cellulose modified with an alumina nanolayer. The activation energy of the desorption process is higher than the activation energy of the adsorption process, which characterizes the adsorption as ionic. The negative value of entropy indicates that in the course of sorption, an adsorption complex “aluminum-fluorine” is formed, where the system is more ordered than the initial system in which fluorine ions are in solution. The limiting stages of the process are revealed. The high sorption capacity of the resulting bacterial cellulose-based composite material obtained by means of biosynthesis through cultivation of the bacterium Komagataeibacter sucrofermentans B-11267 was demonstrated.

Introducing SiC/C dual-interface on porous silicon anode by a conventional exothermic displacement reaction for improved cycle performance

The poor cyclability and high cost are the two major obstacles to the commercial applications of Si-based anode materials. Porous structure and carbon coating may facilitate the ion and electron conduction and also restrict the huge volume change of Si anodes. In addition, introducing a ceramic interlayer between Si and C can reduce the chemical reaction of Si with fluorine ions in the electrolyte and hence improve the cyclability. In this work, porous Si anode protected by SiC/C dual-interface is prepared by simply heating fine Mg 2 Si particles in pure CO 2 at 650 °C, based on the conventional exothermic displacement reaction between Mg (released from Mg 2 Si) and CO 2 . The large amount of heat generated during the displacement reaction leads to sharp temperature rise, resulting in the formation of SiC at such a low temperature. The porous Si/SiC/C powders as well as the spherical sample prepared by subsequent spray-drying and pyrolysis process display much improved rate capability and cyclability as compared to the porous Si/C counterpart, due to the enhanced structural integrity induced synergistically by the porous structure, SiC/C dual-interface and spherical structure during the repeated lithiation/delithiation cycles. • SiC/C dual-interface is introduced on porous Si anode at low temperature. • Fine Mg 2 Si leads to high exothermic displacement reaction between Mg and CO 2 . • Porous SiC/C/Si anode exhibits improved rate capability and cyclstability. • Spherical porous SiC/C/Si anode shows the least volume expansion after cycles.

Charge transfer transitions in glasses - Attempt of a systematic review

In glasses, even low levels of dopants or impurities can give rise to very intense and broad charge transfer transitions from ligands (e.g. oxygen or fluorine ions) to the metal ion (L→M), absorbing strongly in the short wavelength ultraviolet. In an attempt of a systematic review of charge transfer transitions, we compile data of various glass systems with high intrinsic transmission that allow the observation of charge transfer (CT) transitions involving cations of different electronic configurations. Various glasses of different composition were selected as matrices, including fluoroaluminate glasses with low P2O5 content (FP10 = 35AlF3–10MgF2–30CaF2–15SrF2–10Sr(PO3)2), phosphate [SrP = Sr(PO3)2, NSP = Na2O-40SrO-50P2O5], silicate (NS = 15Na2O–85SiO2, DS = 33Na2O–67SiO2), aluminosilicate (BCAS = 10BaO–10CaO–15Al2O3–65SiO2) and borosilicate (NBS1 = 16Na2O–10B2O3–74SiO2, NBS2 = 4Na2O–1Al2O3–21B2O3–74SiO2, Duran = 5Na2O/K2O–1Al2O3–12B2O3–82SiO2) compositions. All glasses were prepared from very high purity materials and doped with various metal ions. Charge transfer transitions of electrons to or from these cations induce absorption and photoluminescence phenomena in the ultraviolet and visible spectral region, which were recorded by optical spectroscopy.Charge transfer transitions were considered for empty valence orbitals, that is, for the high valent 3d, 4d and 5d ions, and for Zn2+, Ag+, Cu+ with full d10 orbitals. 3d, 4d and 5d ions with partially filled valence orbitals that could be stabilized in the named glasses are studied as well. Doping concentrations for these allowed transitions typically ranged from 5 to 5000 wt-ppm of metal ions, with some samples also displaying higher dopant levels.Inter valence charge transfer (IVCT) transitions directly from one metal ion to a neighboring metal ion (M→M) of the same element or metal to metal charge transfer (MM-CT) between ions of different elements can also induce strong visible absorption and deep coloring for which some examples will be discussed.

Leaching behavior and environmental safety evaluation of fluorine ions from shotcrete with high-fluorine alkali-free liquid accelerator.

High-fluorine alkali-free liquid accelerator (AF-hf, F- concentration was about 2.31g/L) was still used in engineering because of its low cost, excellent stability, and coagulation-promoting effect. The main purpose of this study was to explore the leaching behavior of fluorine ions in shotcrete for tunnel lining with high-fluorine alkali-free liquid accelerator and whether there was fluoride pollution. The setting time and mechanical properties of cement paste and mortar with AF-hf were tested. Under different environmental conditions, F- leaching concentration from sprayed concrete was studied comparatively. Moreover, XRD and SEM were used to analyze the crystal composition and micro morphology of hydration products. The experimental results showed that with the increase of AF-hf dosage, the setting time of cement paste was greatly shortened, and later strength of mortar and shotcrete could meet the construction requirements. In addition, when the leaching solution type (including Na2CO3, Na3PO4, Na2SO4, and NaNO3) and testing conditions (particle size, soaking temperature, leaching solutions) were different, F- leaching concentration changed regularly, and the minimum value was more than 20 mg/L, which might cause fluorine pollution to groundwater and soil. After shotcrete samples were soaked, the CaF2 peaks' intensity was relatively weaker and Ca(OH)2 decreased obviously. Meanwhile, cement hydration products became looser and abundant of flaky C-S-H gel transformed into fibrous and chained structure.

A holistic study on fluoride-contaminated groundwater models and its widespread effects in healthcare and irrigation.

Groundwater is a key resource in the world. Its importance is often undermined, despite the various applications which include irrigation, drinking, sanitation, and industrial uses. One of the contaminants of groundwater is fluoride or the fluorine ion. Fluoride is a common pollutant of water, carrying potential benefits and costs to various sectors. Fluoride contamination of groundwater can impact humans, animals, healthcare, and the agricultural sector in direct or indirect ways. This paper aims to establish the definition of fluoride contamination of groundwater and simultaneously provide an outline of a few common sources that may cause fluoride contamination. Furthermore, this study will lay out the impacts of fluoride-contaminated groundwater on two sectors: healthcare and agriculture/irrigation. This study will also summarize various other research projects conducted across the world, which deliver promising evidence to support the points made throughout the paper. In addition to a detailed analysis of the impacts of fluoride on the healthcare and agricultural sector, this study also evaluates few other challenges which this issue poses and how to overcome them in the near future. A summation of deflouridation techniques is included, along with the future scope pertaining to the field of fluoride contamination. Another objective of the study is to spread awareness about the various health impacts that fluoride contamination poses and encourages consumption of fluoride in accordance with the set limit of 0.5-1.5 mg/L. The motivation behind writing this review is to compile and document various researches, along with an address on this prevalent issue to minimize the detrimental impacts and potential health risks on the society. The results of this study help to minimize risks in the future and encourage scientists to come up with mitigation strategies to ensure a safer environment.

Fluorine Accumulation in Sunflower and Its Photosynthetic Response

In order to investigate the practicability to phytoremediation fluoride in wastewater by sunflower, experiment was carried out by hydroponic culture with oilseed type sunflower (Helianthus annuus L.) seedlings. The results indicated that fluorine concentrations in organs of sunflower were significantly increased with increasing solution concentrations and the content order of fluorine in sunflower organs was: roots> leaves> stems. The translocation factor was between 0.045-0.095, indicating that sunflower cannot effectively transport fluorine ions from the roots to the aerial part. The Pn, Gs and Tr of sunflower leaves decreased significantly with the increase of fluoride concentration. The Ci first decreased and then increased with the increase of fluoride concentration. Those results showed that the main reason for the decrease of Pn was the stomatal limitation when the F-1 concentration was between 0 and 20 mg L-1, and the non-stomatal limitation was the main reason for the decrease of Pn when the concentration of F-1 was between 50 and 150 mg L-1. The maximum concentration of fluoride ions in which sunflower can endure was 87 mg L-1.

Reduction of Fluorine Diffusion and Improvement of Dark Current Using Carbon Implantation in CMOS Image Sensor

Recently, the demand of a high resolution complementary metal-oxide semiconductor (CMOS) image sensor is dramatically increasing. As the pixel size reduces to submicron, however, the quality of the sensor image decreases. In particular, the dark current can act as a large noise source resulting in reduction of the quality of the sensor image. Fluorine ion implantation was commonly used to improve the dark current by reducing the trap state density. However, the implanted fluorine diffused to the outside of the silicon surface and disappeared after annealing process. In this paper, we analyzed the effects of carbon implantation on the fluorine diffusion and the dark current characteristics of the CMOS image sensor. As the carbon was implanted with dose of 5.0 × 1014 and 1 × 1015 ions/cm2 in N+ area of FD region, the retained dose of fluorine was improved by more than 131% and 242%, respectively than no carbon implantation indicating that the higher concentration of the carbon implantation, the higher the retained dose of fluorine after annealing. As the retained fluorine concentration increased, the minority carriers of electrons or holes decreased by more Si-F bond formation, resulting in increasing the sheet resistance. When carbon was implanted with 1.0 × 1015 ions/cm2, the defective pixel, dark current, transient noise, and flicker were much improved by 25%, 9.4%, 1%, and 28%, respectively compared to no carbon implantation. Therefore, the diffusion of fluorine after annealing could be improved by the carbon implantation leading to improvement of the dark current characteristics.

Butyl-Methyl-Pyridinium Tetrafluoroborate Confined in Mesoporous Silica Xerogels: Thermal Behaviour and Matrix-Template Interaction.

Organic-inorganic silica composites have been prepared via acid catalyzed sol-gel route using tetramethoxysilan (TMOS) and methyl-trimethoxysilane (MTMS) as silica precursors and n-butyl-3-methylpyridinium tetrafluoroborate ([bmPy][BF4]) as co-solvent and pore template, by varying the content of the ionic liquid (IL). Morphology of the xerogels prepared using the ionic liquid templating agent were investigated using scanning electron microscopy and small angle neutron scattering (SANS). Thermal analysis has been used in order to evaluate the thermal and structural stability of the materials, in both nitrogen and synthetic air atmosphere. In nitrogen atmosphere, the IL decomposition took place in one step starting above 150 °C and completed in the 150–460 °C temperature interval. In synthetic air atmosphere, the IL decomposition produced two-step mass loss, mainly in the 170–430 °C temperature interval. The decomposition mechanism of the IL inside the silica matrix was studied by mass spectrometric evolved gas analysis (MSEGA). The measurements showed that the degradation of the IL’s longer side chain (butyl) starts at low temperature (above 150 °C) through a C-N bond cleavage, initiated by the nucleophilic attack of a fluorine ion.

Structure, Magnetism, and Thermal Stability of La2NiO2.5F3: A Ruddlesden-Popper Oxyfluoride Crystallizing in Space Group P42/nnm.

We report on the new Ruddlesden-Popper (RP) oxyfluoride La2NiO2.5F3 containing an unprecedented high amount of fluorine and Ni2+. This oxyfluoride was prepared by topochemical low-temperature fluorination of La2NiO4, which was obtained by a soft chemistry synthesis, with poly(vinylidene difluoride) (PVDF) as fluorinating agent. La2NiO2.5F3 is the first n = 1 RP compound crystallizing in the tetragonal space group P42/nnm (a = 5.7297(6) Å and c = 13.0106(2) Å). The crystal structure shows a unique tilting scheme of the NiO4F2 octahedra that has so far been only theoretically predicted. Combined neutron and X-ray powder diffraction experiments together with bond-valence-sum and DFT+U calculations reveal an unusual anion ordering with fluoride being located on the apical anion sites of the NiO4F2 octahedra. Excess fluorine ions were found to populate two of the four interstitial anion sites in an ordered fashion. A third interstitial anion position is occupied by oxygen ions while the fourth site remains unoccupied. This hitherto unobserved ordering scenario in RP oxyfluorides promotes a strong layerwise alternating tilting of the NiO4F2 octahedra. Magnetic measurements show strong antiferromagnetic interactions with a high Néel temperature of about 225 K and a pronounced ZFC/FC splitting most likely as the result of a small ferromagnetic moment arising from spin canting. The electronic structure was characterized by DFT and UV-vis spectroscopy, and a strong increase of Eg was found compared to La2NiO4 (3.4 eV vs 1.3 eV).