Concentrations Of Br Research Articles

High-performance p-channel CuIBr thin-film transistor synthesized from solution in the atmosphere

The p-type transparent semiconductor CuI has a high potential to be used in thin film transistors (TFTs) due to high hole mobility and solution processability. However, the lower copper vacancy formation energy and the subsequent high hole concentration in CuI lead to a low on/off current ratio (ION/IOFF) for CuI TFT devices. The density functional theory results suggest that the copper vacancy formation energy increases with the CuBr content in the Br-doped CuI film, resulting in lower hole concentration. Alloying CuI with CuBr is proposed to reduce the hole concentration in the CuIBr alloy. The CuIBr TFTs with Br content ranging from 0% to 10% were fabricated using the solution method. It is found that the hole mobility decreases from 8 to 1 cm2 V−1 s−1, while the ION/IOFF ratio increases from 102 to 104 with the increasing Br content. The CuIBr TFT with 7.5% Br content exhibits a high hole mobility larger than 5 cm2 V−1 s−1 and high ION/IOFF ratio of 104, which paves the way for inorganic-based CMOS circuits on flexible and transparent substrates.

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The study aimed to assess concentrations of heavy metals in soil samples on both sides along the three Niles (Blue, White, and Nile Rivers) and Almogran area (Tuti Island) in Khartoum city (the capital of Sudan country) after the overflow season. Concentrations of heavy metals Br, Cu, Ni, Pb, Co, Rb, Cr, Zn, Zr, Sr, Mn, Ti, K, Ca, and Fe were determined using Xray fluorescence (XRF) techniques compatible with direct analysis of soils. The results showed that the element's concentration along the Blue Nile is higher than White Nile, Nile river, and Almogran area. In addition, Enrichment Factor (EF) and Geoaccumulation index (GI) factor was calculated, and both are in recommended ranges except EF for Ni high at Blue Nile 2.58, which is more than recommended value (2).

Bromide ion enhancing the phytodegradation of emerging phenolic pollutants and its mechanisms mediating wheat resistance to phenolic pollutants stress

The phytodegradation of emerging phenolic pollutants (EPPs) has attracted widespread attention. However, the impact of bromide ions (Br−) on the phytodegradation of EPPs and its mechanism mediating wheat resistance to EPPs stress have rarely been reported. Our research discovered that Br− enhanced the removal of EPPs (7.5, 15 mg/L) in a dark hydroponic wheat system. The degradation efficiency of acetaminophen (ACE), bisphenol A (BPA) and 1-naphthol (1-NP) increased 2.2, 2.8 and 1.28 times as Br− concentration increased from 0 to 1 mM, respectively. In the presence of Br−, the mono- and dibromo-products of ACE and BPA were produced in the dark hydroponic wheat system, while 1-NP showed higher degradation efficiency but no bromine substitution formation. EPPs induced oxidative damage and root growth inhibition in wheat. The addition of Br− enhanced the chlorophyll content, indole-3-acetic acid (IAA) content and antioxidant potential to alleviate EPPs stress. Principal component analysis (PCA) revealed significant separation of different Br− stimuli, that is, the low concentrations of Br− (0.1 mM) enhanced the content of IAA by 28.6%, while higher concentrations of Br− (0.5, 1 mM) alleviated membrane lipid peroxidation by improving peroxidase (POD) activity. This is the first report that Br− could stimulate the synthesis of IAA via indole acetonitrile (IAN) pathway and hydrolysis of IAA-conjugates. This study provides more support for the feasibility of phytoremediation techniques for phenolic pollutants and references for the assessment of ecological risks and health hazards of EPPs.

A Study of Elemental Composition and Risk Assessment Due to Exposure to Indoor PM10 in Two Residences in Mexico City

Samples of airborne particles with aerodynamic diameters smaller than 10 µm (PM10) were collected in 2021 at two households in the Metropolitan Area of Mexico City. Both sites are in areas with different characteristics (residential or industrial zones). Simultaneous sampling indoors and outdoors was carried out at the two locations, using low-volume samplers. The study aimed to determine the indoor and outdoor gravimetric mass and elemental concentrations, identify emitting sources and possible penetration towards the households enhanced by natural ventilation, and assess risks to human health due to inhalation, ingestion, and dermal absorption, through hazard quotients. Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Br, Se, and Pb concentrations were measured with X-ray fluorescence. Mass concentrations were higher indoors than outdoors, and most elemental concentrations had similar values in both environments. Cluster analysis was applied to identify possible emitting sources. The results showed a strong penetration of geogenic and industrial emissions at the Iztapalapa site, while only particles of industrial origin entered the interior of the Tlalnepantla dwelling, in both cases caused by the natural ventilation of the households. Health risks due to exposure to particles containing Fe, Ni, Cu, Zn, and Mn are not significant, and Pb and Cr only pose a risk via ingestion for men and women, although for children, there is a risk due to ingestion of all these elements.

Architecture of the Lesser Antilles Arc Illustrated by Melt Inclusions

Abstract Volatiles are an essential aspect of subduction zones and constraining their cycling through subduction zones is of prime importance to better understand the genesis, transport, storage and eruption of arc magmas. Here we performed an along-arc investigation of the chemical composition of melt inclusions trapped in minerals representative of ten volcanic centers and 23 key explosive eruptions along the presently active Lesser Antilles arc, from Montserrat in the North to St. Vincent in the South. We use the melt inclusion compositions to reconstruct pre-eruptive conditions, especially pre-eruptive magma storage and degassing levels that highlight how the magma plumbing system is organized and works and to discuss magma source characteristics. All major and selected trace elements and volatiles (H2O, CO2, S, halogens (F, Cl, Br)) have been measured on the same melt inclusions when possible. Eruptions dominantly involved andesitic to dacitic magmas (Montserrat, Guadeloupe, Dominica, Martinique, St. Lucia) and basaltic andesite magmas from St. Vincent. Melt inclusions have been used as pressure probes for magmas, for inferring crustal equilibration pressures. We shed light on the systematic occurrence and lateral complexity of a vertical transcrustal magmatic systems feeding active volcanoes. The geochemical view of the architecture of the plumbing system and in particular the Moho's depth is more variable than the view obtained by seismic data along the Lesser Antilles arc. We propose that the discontinuity between the upper and the middle crust is a major magma ponding zone beneath most of the Lesser Antilles islands and that the crustal structure thus imparts a control on the geochemical signature of arc lavas. Melt inclusions are highly differentiated (dacitic to rhyolitic in composition), so they are distant in composition from the primary, mantle-derived magmas, but they provide indirect information about the magmatic sources. The along-arc variability in Y and heavy rare earth element contents of melt inclusions is consistent with the presence of garnet in the mantle source. Our results also indicate an important contribution of oxidized and saline slab-derived fluids to the magma source predominantly in the southern Lesser Antilles that may have implication on the accretionary system behavior. In addition, a high geographical gradient between sediment melt and slab-derived fluid contributions, illustrating high variability in magmas erupted in close spatial association is reported for some islands, such as Martinique and Dominica. Volatile contents are variable for MIs across the arc: the highest H2O (<8 wt%), Cl (up to 3800 ppm) and Br (up to 20 ppm) concentrations occur in MIs from Dominica. However, there is no systematic correlation between MI volatile content and position along the arc. Halogen Cl/F and Cl/Br ratios vary from one island to another, even between the different eruptions, but without any along arc zoning, indicating that halogen fractionation occurred by fluid transfer (variable assimilation rate of fluids derived from seawater) or by heterogeneities of mantle origin inherited from the initial differentiation of the mantle.

Exogenous hormone application regulates dwarf mutant plant height in Sophora davidii (Franch.) Skeels by changing endogenous hormone levels

Dwarf mutants are valuable materials for investigating plant gene function and developing new crop varieties. In the present study, dwarf mutant (D-CK) and wild-type (W-CK) Sophora davidii (Franch.) Skeels plants foliarly sprayed with distilled water were used as controls, and dwarf mutants were treated with different concentrations of gibberellin A3 (GA3; 20, 40 and 60 mg L-1), brassinosteroid (BR; 12.5, 25 and 50 mg L-1); and auxin indole-3-acetic acid (IAA; 12.5, 25 and 50 mg L-1) to study the changes in plant height at 20, 40 and 60 d after exogenous hormone spraying. The changes in endogenous contents of IAA, GA3, BR, abscisic acid (ABA), jasmonic acid (JA), and salicylic acid (SA) and IAA:ABA ratio in the dwarf mutant plants were also measured at 20, 40 and 60 d after exogenous hormone application. The dwarf mutants reverted to the W-CK height phenotype after 60 d of exogenous spraying with different concentrations of GA3 and BR (except 50 mg·L-1), but after exogenous spraying with IAA, dwarf mutants did not revert to the W-CK height phenotype. Compared with D-CK plants, endogenous GA3, BR and IAA contents in dwarf mutant plants increased to some extent with exogenous spraying of GA3, BR and IAA. The results indicated that exogenous spraying of different concentrations of GA3 and BR regulated S. davidii plant height by promoting the secretion of endogenous GA3, BR, IAA and SA and inhibiting endogenous ABA secretion in dwarf mutant. The height of mutants was sensitive to exogenous GA3 and BR but not to exogenous IAA.

Differences of Relationships between Iodine and Trace Elements in Normal Thyroid and Thyroid Benign Nodules Revealed by X-Ray Fluorescent Analysis

Thyroid Benign Nodules (TBN) are the most common lesions of this endocrine gland. The etiology of TBN is not clear. The aim of this exploratory study was to examine differences in the content of bromine (Br), cooper (Cu), iron (Fe), iodine (I), rubidium (Rb), strontium (Sr), and zinc (Zn), as well as I/Br, I/Cu, I/Fe, I/Rb, I/Sr, and I/Zn content ratios in tissues of normal thyroid and TBN. Thyroid tissue levels of seven Trace Elements (TEs) were prospectively evaluated in 105 apparently healthy persons and in 79 patients with TBN. Measurements were performed using 109Cd and 241Am radionuclide-induced energy-dispersive X-ray fluorescent analysis. Tissue samples were divided into two portions. One was used for morphological study while the other was intended for TEs analysis. It was observed that in TBN the mass fraction of Br, Cu, and Fe were higher, whereas mass fractions of I as well as I/Br, I/Cu, I/Fe, and I/Zn mass fraction ratios were lower than in normal tissues of the thyroid. These changes can potentially be used as TBN markers. Furthermore, it was found that the levels of Br, Cu, Fe, Rb, Sr, and Zn contents in the normal and affected thyroid gland were interconnected and depend on the content of I in thyroid tissue. Because I plays a decisive role in the function of the thyroid gland, the data obtained allow us to conclude that, along with I, at least such TEs as Br, Cu, Fe, Rb, and Zn, if not directly, then indirectly, are involved in the process of thyroid hormone synthesis.

Mineralogical and Structural Analyses of Natural Fluorite from Yantuwaru Mining Site, Nigeria

Experimental studies of natural fluorite have been reported. In this study, combined X-Ray Fluorescence, FTIR and UV-Vis analyses were performed to give mineralogical information about natural fluorspar. The X-ray diffraction technique was also used to determine the crystallographic parameters and structure of the mineral. Results show a variation of Ca contents and low concentration of F, through all fluorite samples due to Ba and Br contents in the samples, causing replacements of impurity ions in the fluorite lattice. REEs in the fluorite samples were to be found responsible for colour. UV-Visible absorption results showed peaks between 209 to 368 nm, which did not affect the fluorite colour. The 224 nm and 365 nm peaks were caused by the electrons and holes trapped in the Ca2+ interstitial and vacancy, respectively. The absorption bands in the visible range relate to the corresponding fluorite samples. The FTIR results showed absorptions causing CO2 and CO32-stretching vibration due to the CaCO3 and OH stretching vibration due to water in the samples. The structural configuration, the lattice parameters, and the planes confirmed a cubic structure. Obtained results confirmed them to be Calcium Fluorite, as expected.

Comparison of the photochemical properties of phthalocyanine and hemiporphyrazine Zn(II) complexes

In DMF (dimethylformamide) solutions containing concentrations of (NEt4)Br (Et = ethyl) between 0.001 and 0.05 M both zinc phthalocyanine (Pc) and hemiporphyrazine (Hp) complexes are dissolved and form species [Zn(Hp)(Br)]–, and [Zn(Pc)(Br)]–. The increase in formation of the hemiporphyrazine bromide adduct is revealed by a linear dependence of the UV–Vis absorption spectrum on the Br– concentration whereas, over the same concentration range, absorption measurements indicate the formation of the phthalocyanine bromide adduct in solution. The x-ray and molecular structure of [NEt4][Zn(Pc)(Br)](H2O)0.33 has been determined showing the coordination of the Br– to the metal center. Photo-induced processes of the Zn complexes were investigated with deaerated solutions in a time scale t ≥10 ns. The 355 nm flash irradiation of [Zn(Hp)(Br)]– produced transient spectra which showed a bathochromic shift of the absorption maximum from 460 nm to 440 nm and an increase of the spectrum rate of decay with increasing Br– concentrations. The initial spectrum is attributed to the (nπ*–LLCTBr→Hp)[Zn(Hp)(Br)]– excited state which reacts with H-atom donors forming a radical [Zn(Hp-H)(Br)]•–. On the other hand, a transient spectrum, λmax ∼600 nm, grows in a time t ≤0.6 µs when [Zn(Pc)(Br)]– is flash irradiated at 355 nm. The photoreactions of these complexes with SCN– and 2-propanol (IPA) were studied. Despite of the apparent similarity between both complexes, IPA was photo-oxidized by both complexes although by different mechanisms, an electron transfer with [Zn(Pc)(Br)]– and an H atom abstraction with [Zn(Hp)(Br)]–. The photo-oxidation of SCN– by [Zn(Pc)(Br)]– but not by [Zn(Hp)(Br)]– makes a remarkable difference between the photochemistries of these complexes.

BiOBr Surface-Functionalized Halide Double-Perovskite Films for Slow Ion Migration and Improved Stability

Surface-tailored lead-free halide double-perovskite (Cs2AgBiX6) thin films are utilized for ion migration studies. A thin surface layer of BiOBr/Cl is grown via intentional annealing of the halide films in ambient conditions. Herein, we physically stacked the two films, viz., Cs2AgBiBr6 and Cs2AgBiCl6, to thermally activate the halide ion migration at different temperatures (room temperature (RT)-150 °C). While annealing, the films' color changes from orange to pale yellow and transparent brown to yellow as a result of the migration of Br- ions from Cs2AgBiBr6 to Cs2AgBiCl6 and Cl- ions from Cs2AgBiCl6 to Cs2AgBiBr6, respectively. Annealing helps in homogenizing the halide ions throughout the films, consequently leading to a mixed phase, i.e., Cs2AgBiClxBr6-x/Cs2AgBiBrxCl6-x (x = 0 to 6) formation. The movement of ions is understood by absorption studies performed at regular time intervals. These investigations reveal a redshift (from 366 to 386 nm) and a blueshift (from 435 to 386 nm) in absorption spectra, indicating the migration of Br- and Cl- toward Cs2AgBiCl6 and Cs2AgBiBr6, respectively. The films characterized using X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) reveal the presence of a peak at 2θ = 10.90° and binding energy of 158.1 eV, respectively, corresponding to the formation of Bi-O bonds at the film surface. Also, XRD studies show a lower 2θ shift of the diffraction peak in the case of Cs2AgBiCl6 films and a higher 2θ shift in the case of Cs2AgBiB6 films, which further confirms the migration of Cl- and Br- from one film to the other. XPS investigations confirm the compositional change with a gradual increment in the concentration of Br-/Cl- with an increase in heating time for Cs2AgBiCl6/Cs2AgBiBr6 films. All these studies confirm thermal diffusion of halide ions in double-perovskite films. Further, from the exponential decay of the absorption spectra, the rate constant for halide (Br) ion diffusion is calculated, which shows an increment from 1.7 × 10-6 s-1 at RT to 12.1 × 10-3 s-1 at 150 °C. The temperature-dependent rate constant follows Arrhenius behavior and renders an activation energy of 0.42 eV (0.35 eV) for bromide (chloride) ion mobility. A larger estimated value as compared to the reported values for Cs2AgBiBr6 wafers (∼0.20 eV) reveals a slow mobility of halide ions in thin films of Cs2AgBiBr6/Cl6. The formation of a BiOBr passivation layer at the surface of Cs2AgBiBr6 thin film might be one of the plausible causes of the slow anion diffusion in the present work. Slow ion migration is an indication that the films are stable and of high-quality.

Lithium and brine geochemistry in the Qianjiang Formation of the Jianghan Basin, central China

The Li-enriched oilfield brine is a very important lithium resource. It has gained much attention and become the target of active Li surveys with the growing global demand for Li. However, only little is known about their feature and nature. In the study, hydrochemical data from 155 oil wells tapping the Eocene to Lower Oligocene Qianjiang Formation of the Jianghan Basin, central China indicate that the brines are of the Na–Cl or Na–Ca–Cl type and are characterized by highly variable Li contents of 7.56 to 150 mg/L, with Mg/Li ratios less than 11.65. High Na/Cl and Cl/Br molar ratios indicate distinct contributions from halite dissolution. The Ca excess, Na deficit and Ca/Mg and Ca/Sr molar ratios in the brines imply multiple diagenetic processes, including halite dissolution, dolomitization, albitization and calcite or anhydrite cementation. The lithium contents of these brines have a weak relationship with the salinity and a negative correlation with Cl/Br ratios, possibly indicating that these Qianjiang oilfield brines have been diluted by secondary brines derived from halite dissolution. The spatial distribution patterns for Li and B concentrations of the brines are different from those for salinity and Br contents and show a geographic pattern, indicating that Li enrichment in the Qianjiang brines is likely connected with geothermal sources associated with volcanic activity.

Controlled growth and spectroscopy characterization of blue violet perovskite quantum dots in borate glasses

Blue violet light emitting CsPb(Cl/Br)3 perovskite quantum dots glasses (QDGs) have been successfully fabricated in multi-component borate glass matrix by melt quenching and heat treatment. The spectral characteristics have been evaluated by photoluminescence (PL), PL excitation (PLE), PL decay and absorption spectra. The recipe and preparation conditions have been optimized for controlled growth of QDs. By using raw materials of NH4Br/NH4Cl/PbO and crucible cover, optimizing composition of Na2O/K2O in matrix, melting temperature and time, heat treatment temperature and time, and NH4Cl and NH4Br contents, we have finally realized blue violet exciton emission in target range of 405–440 nm. The PL wavelength adjustment is comprehensive effect of the abovementioned influence factors. The emission in short wavelength of 405–440 nm is due to controlled growth of the QDs. In final CsPb(Cl/Br)3 QDs, the contents of Cl and Br are suitable and the Cl/Br ratios are large. A little Br is necessary for growth of CsPb(Cl/Br)3 QDs and then the Br is partially replaced by Cl at suitable treatment condition. Unsymmetrical PL spectrum profile of some samples is explained as reabsorption effect by monitoring PL spectral profile and PL decay. The temperature characteristics of PL spectra show good recoverability after a temperature cycle.

Halogen enrichment in the North American lithospheric mantle from the dehydration of the Farallon plate

A greater quantity of halogens (F, Cl, Br, and I) appear to be subducted globally than are erupted at magmatic arcs, requiring either an increase in the mantle halogen budget through time or an additional output pathway or reservoir. The sub-continental lithospheric mantle (SCLM) is one such reservoir. SCLM can be enriched in volatile elements after metasomatism by fluids or melts from subducting oceanic lithosphere. We analyzed the bulk halogen content (F, Cl, Br, and I) of 28 variably metasomatized spinel and garnet peridotite xenoliths from the Navajo Volcanic Field (NVF; Central Colorado Plateau) to constrain the effects of the subducting Farallon plate-derived metasomatism on the halogen content of the western North American SCLM. We also analyzed 33 anhydrous spinel peridotites from various localities on and around the Colorado Plateau, as well as xenoliths from Oahu, Hawaii, and Eifel, Germany to compare them to the modally hydrated NVF xenoliths. Cl, Br, and I are enriched in NVF xenoliths relative to the depleted mantle, correlating with olivine oxygen isotope values and indices of metasomatism. F is less enriched, indicating preferential retention in the slab residue. Br/Cl and I/Cl are similar to partially dehydrated serpentinite, indicating that the source of these fluids is consistent with serpentinized oceanic lithosphere of the Farallon plate. Anhydrous xenoliths from the southwestern United States have more depleted mantle-like Cl and F contents but have highly enriched Br contents similar to the NVF xenoliths. Similar to NVF xenoliths, anhydrous xenolith Br/Cl and I/Cl suggest a Farallon derived serpentinite source of halogen enrichment. These results indicate that the Farallon slab sequestered halogens in the North American SCLM of the central and south Colorado Plateau and the southern Rio Grande Rift. Therefore, halogen sequestration in the SCLM may be a critical component in the global halogen cycle.

Analysis of the Elemental Composition of Gonads, Gametes and Larvae of the Mussel <i>Mytilus galloprovincialis</i> in the Spawning Period

In this work, we studied the elemental composition of gonads, eggs, sperm and larvae of the mussel Mytilus galloprovincialis during spawning, when the contents of biologically active compounds and minerals are maximal. A comparative analysis of the contents showed that the elements are involved in the mussel gametogenesis in different pathways. There were significant differences in the contents of Li, B, Mg, Si, P, K, Ca, V, Cr, Mn, Fe, Co, Ni, Zn, Ge, As, Se, Br, Rb, Sr, Mo, Pd, Sn, I, Ba and Ce in male and female gonads before and after spawning, gametes and larvae of mussels. It is likely that some of the listed elements are not only passively accumulated in the mollusk body, but are also essential, being directly involved in the reproduction process. Most of significant differences in the element contents were found between eggs and larvae and between male gonads before spawning and sperm. By spawning, mussel gonads accumulated mainly p- and d-elements, apparently due to the ability of their ions to form complexes and, consequently, to be included in the structure of enzymes. The contents of B, Mg, Si, P, K, Ca, Cr, Mn, Fe, Cu, Zn, As, Se, Br, Sr and Ba in male and female gonads, gametes and larvae were an order or several orders of magnitude higher than those of other elements. The contents of Ca, Fe, Sr, Sn and I in mussel larvae were significantly higher than in gonads and gametes. Sn is a technological hydropollutant, and thus, larvae can serve as a bioindicator of the aquatic environment pollution with this element. The data obtained are of practical interest for improving the biotechnology of reproduction of marine hydrobionts and obtaining functional products based on them, which is important for the optimization of aquaculture management and for addressing human health-related issues.

Ionothermal Crystallization of SAPO-11 Using Novel Pyridinium Ionic Liquid and Its Catalytic Activity in Esterification of Levulinic Acid into Ethyl Levulinate

A study using a novel pyridinium ionic liquid, namely 1-propylpyridinium bromide ([PPy]Br), to crystallize SAPO-11 under ionothermal conditions is reported. By carefully following the crystallization process, SAPO-11 can readily be crystallized in the presence of [PPy]Br, which serves as a synthesis solvent and structure-directing agent, at 150 °C after 133 h of heating. The study also focuses on manipulating other synthesis parameters (e.g., crystallization temperature, phosphorous content, silicon amount and [PPy]Br concentration) and investigating their respective effects on the formation of SAPO-11. The crystallized SAPO-11 has an acidic nature and a high surface area. Under conductive instant heating conditions, the SAPO-11 catalyst is very active in the conversion of levulinic acid into ethyl levulinate; 93.4% conversion and 100% selectivity of ethyl levulinate are recorded at 180 °C after 30 min of reaction. This result is comparable to or even better than those of conventional homogeneous catalysts.

A lead-free environment-friendly material for optoelectronic and photocatalytic applications: A computational approach

The structural, optoelectronic, and photocatalytic properties of KCaF3-xBrx, where x indicates Br concentration (x = 0, 0.6, 1.2, 1.8, 2.4, 3.0), are described here using density functional theory. Computed structural and optoelectronic results for pristine c-KCaF3 are well consistent with existing literature. Bandgap was engineered by impurity inclusion such that the proposed material changes its bandgap for both generalized gradient approximation (GGA) and Heyd, Scuseria, and Ernzerhof hybrid functional (HSE03) formalism from 5.638 eV to 3.807 eV and from 8.538eV to 2.772 eV respectively. One of the most important criteria for proposing a new end material is structural and mechanical stability, thus the tolerance factor and Born's requirements were used to establish the end materials' stable cubic nature. Optical parameters such as dielectric function, reflection and absorption coefficient, refractive index, and energy loss function are calculated and analyzed up to the photon energy range of 0–35 eV. A redshift was observed whereas the refractive index values for different concentration shows continuous change except for x = 2.6. The highest value of reflectivity is observed for KCaBr3 making it useful for several thermoelectric applications. Photocatalytic properties were predicted using a band edge diagram, indicating that the presented series of materials is a useful candidate for hydrogen evolution reaction (HER), and oxygen evolution reaction (OER). Br substitution at the anionic site of c-KCaF3 has been reported first ever, with promising optical, elastic, and photocatalytic properties that will inspire further research on this material.

Prospects for Eocene potash deposition in the East Tethyan domain: New evidence from fluid inclusions and chlorine isotope of halite crystals in the Kuqa Basin, NW China

The level of the Tethys Sea increased several times during the deposition of Mesozoic to Cenozoic sediments in the Kuqa Basin in the Tarim Block. The basin contains Paleogene to Neogene units containing evaporite-rich layers, which are favourable sources for economic concentration of potash (K-rich salt). However, the basin’s geology is poorly understood, lacking knowledge of the source of the brine, paleo-water temperatures, and the degree of evaporation. As a result, the exploration for potash mineralisation has been limited. This study documents the geochemistry, fluid inclusions, and Cl-isotope of Early Eocene halite crystals from the Kuqa Basin. The results show that the homogenisation temperatures of primary fluid inclusions in halite range between 20° and 57 °C, which is close to the temperature range of the seawater in the Tethyan sea during the same period. The average value of ∼ 32 °C is taken as the average temperature of the salt-forming brine in the Early Eocene. The homogenisation temperatures of the inclusions are generally high, with a maximum temperature of ∼ 57 °C, which is consistent with the global Paleocene–Eocene thermal maximum (PETM) climatic event, indicating that the salt-forming brine has experienced long-term and sustained high temperatures and short-term extremely high temperatures. This is consistent with the high temperatures recorded during the deposition of potash in other parts of the earth, such as ∼ 59 °C for the Silurian Michigan Basin in the USA and ∼ 58 °C for the Quaternary Lop Nur region in Mongolia. In addition, the Br content of the halite samples is between 58 and 125 ppm, and the Br × 103/Cl value is between 0.11 and 0.21, which is consistent with the evaporation curve of seawater, indicating that there is a marine environment favourable for potash deposition. The value of δ37Cl is between −0.7 and −0.14 ‰ showing that the salinity of the brine evolved to a higher concentration, especially during the later stage of potash deposition. This indicates that the potential for the presence of potash deposits in the Early Eocene Kuqa Basin is high.

Thermodynamic Origin of the Photostability of the Two-Dimensional Perovskite PEA2Pb(I1-x Br x )4.

The two-dimensional (2D) mixed halide perovskite PEA2Pb(I1-x Br x )4 exhibits high phase stability under illumination as compared to the three-dimensional (3D) counterpart MAPb(I1-x Br x )3. We explain this difference using a thermodynamic theory that considers the sum of a compositional and a photocarrier free energy. Ab initio calculations show that the improved compositional phase stability of the 2D perovskite is caused by a preferred I-Br distribution, leading to a much lower critical temperature for halide segregation in the dark than for the 3D perovskite. Moreover, a smaller increase of the band gap with Br concentration x and a markedly shorter photocarrier lifetime in the 2D perovskite reduce the driving force for phase segregation under illumination, enhancing the photostability.

Charge Carrier Recombination Dynamics in MAPb(BrxCl1-x)3 Single Crystals.

Understanding carrier recombination processes in MAPb(BrxCl1-x)3 crystals is essential for their photoelectrical applications. In this work, carrier recombination dynamics in MAPb(BrxCl1-x)3 single crystals were studied by steady-state photoluminescence (PL), time-resolved photoluminescence (TRPL), and time-resolved microwave photoconductivity (TRMC). By comparing TRPL and TRMC, we find TRPL of MAPb(BrxCl1-x)3 (x < 0.98) single crystals is dominated by a hole trapping process while the long-lived component of TRMC is dominated by an electron trapping process. We also find both electron and hole trapping rates of MAPb(BrxCl1-x)3 (x < 0.98) crystals decrease with an increase in Br content. A temperature-dependent PL study shows there are shallow trap states besides the deep level trap states in the MAPb(Br0.82Cl0.18)3 crystal. The activation energy for holes in shallow trap states detrapped into the valence band is ∼0.1 eV, while the activation energy for free holes to be trapped into deep trap states is ∼0.4 eV. This work provides insight into carrier recombination processes in MAPb(BrxCl1-x)3 single crystals.

Study of trace elements in stranded green turtles (Chelonia mydas), hawksbill turtles (Eretmochelys imbricata), and olive ridley turtles (Lepidochelys olivacea) in Gulf of Thailand and Andaman Sea.

The purpose of this study was to survey and compare the amounts of elements in the serum of stranded sea turtles from the Gulf of Thailand and the Andaman Sea. The sea turtles from the Gulf of Thailand had Ca, Mg, P, S, Se, and Si concentrations significantly higher than those in sea turtles from the Andaman Sea. The Ni and Pb concentrations of sea turtles from the Gulf of Thailand was higher, but not significantly so, than in sea turtles from the Andaman Sea. Rb was detected only in sea turtles from the Gulf of Thailand. This may have been related to the industrial activities in Eastern Thailand. The concentration of Br in the sea turtles from the Andaman Sea were significantly higher than those in sea turtles from the Gulf of Thailand. The higher serum concentration of Cu in hawksbill (H) and olive ridley turtles (O) than in green turtles may be due to hemocyanin, as an important component in the blood of crustaceans. The higher Fe concentration in the serum from green turtles than for H and O may be due to chlorophyll, which is an important component of chloroplasts in eel grass. Co was not found in the serum of green turtles but was found in the serum of H and O. The monitoring of important elements in sea turtles may be used as a tool to assess the levels of pollution in marine ecosystems.