The first rubidium and cesium enediamide complexes based on bulky 1,4-diaza-1,3-diene ligands (DADs) have been prepared by metalation of either 1,4-bis(2,6-diisopropylphenyl)-1,4-diaza-1,3-butadiene (1, = H2DADDipp) or 1,4-bis(2,6-diisopropylphenyl)-2,3-dimethyl-1,4-diaza-1,3-butadiene (2, = Me2DADDipp) with an excess of Rb or Cs metals in coordinating solvents such as tetrahydrofuran (THF) or 1,2-dimethoxyethane (DME). All new complexes were fully characterized by spectroscopic and analytical methods as well as single-crystal X-ray diffraction studies.

Extracting cesium (Cs) from nonexpandable illite clay is important in the remediation of radioactive Cs-contaminated soil. In this study, we investigated a chloride salt treatment technique for the removal of Cs from illite. Cs-loaded illite samples with initial Cs concentrations of 2430 and 690 ppm were treated using a NaCl-MgCl2-CaCl2 ternary salt system at 400-850 °C under ambient pressure to suppress Cs loss by vaporization. As a result of the treatment at 850 °C, wherein the salt was in a molten state, the Cs concentration was reduced by 99.5% (to 11.6 ppm) in the first sample and by 99.4% (to 3.86 ppm) in the second sample. Cs removal was achieved for these two samples even in a solid-state reaction at 400 °C, with reductions of 83.3% (407 ppm) and 73.3% (184 ppm), respectively. CsCl was formed by the reaction and remained stable in the salt. The incorporation of cations from the salt (mainly Mg2+) to illite induced structural evolution forming an indialite phase to expel Cs from the clay samples.

Cesium lead halide perovskite nanocrystals are widely studied as among the most attractive emissive nanomaterials because of their high photoluminescence quantum yield and tunable emission wavelengths over the whole visible-light region by the halide ion-exchange reaction. However, the reactions were often observed in solution and generally very fast, which interferes with the fine-tuning capability of the emission properties. Here, we report a novel nanocrystal-organogel hybrid soft material in which the perovskite nanocrystals in a supramolecular gel exhibit extremely slow and inhomogeneous anion-exchange reactions that are different from those in solution. Furthermore, the inhomogeneous emission in the gel became homogeneous over several days due to a slow diffusion.

Two new phosphine ligands, diphenylmethylphosphine (DPMP) and triphenylphosphine (TPP), were introduced onto cesium lead bromoiodide nanocrystals (CsPbBrI2 NCs) to improve air stability in the ambient atmosphere. Incorporating DPMP or TPP ligands can also enhance film-forming and optoelectronic properties of the CsPbBrI2 NCs. The results reveal that DPMP is a better ligand to stabilize the emission of CsPbBrI2 NCs than TPP after storage for 21 days. The increased carrier lifetime and photoluminescence quantum yield (PLQY) of perovskite NCs are due to the surface passivation by DPMP or TPP ligands, which reduces nonradiative recombination at the trap sites. The DPMP and TPP-treated CsPbBrI2 NCs were successfully utilized as red emitters for fabricating perovskite light-emitting diodes with enhanced performance and prolonged device lifetime relative to the pristine one.

In this study, we report the utilization of low-temperature solution-processed Cs-doped VOX thin films as the hole extraction layers (HELs) in perovskite solar cells (PSCs). It is found that the VOX:yCs (where y is the mole ratio of Cs versus V and y = 0.1, 0.3, and 0.5) thin films possess better electrical conductivities than that of the pristine VOX thin film. As a result, the PSCs incorporated with the VOX:yCs HEL exhibit large fill factors and high short-circuit currents, with consequently high power conversion efficiencies, which is more than 30% enhancement as compared with pristine VOX HEL. Our studies provide a facial way to enhance the electrical conductivity of the hole extraction layer for boosting device performance of perovskite solar cells.

Following the nuclear accident at the Fukushima Daiichi Nuclear Power Plant in 2011, even the municipal solid waste (MSW) and sewage sludge (SS) in northeastern Japan became contaminated by radioactive nuclides such as 137Cs and 134Cs. To understand the state of radioactive cesium (r-Cs) in the incineration residues of the municipal wastes, research groups studied the concentration and the chemical form of r-Cs in the residues, as well as its water-leaching behavior. In the present study, we conducted thermodynamic equilibrium calculations to estimate the possible chemical forms of r-Cs in the incineration residues. Thermodynamic data for cesium oxides and aluminosilicates were collected and compiled into a new database to perform equilibrium calculations for systems that include Cs. The calculation results suggested that Cs (radiocesium and stable cesium) in municipal solid waste was transformed into gaseous CsCl or crystalline aluminosilicate at incineration temperatures and, when a molten aluminosilicate phase (i.e., slag phase) was generated, a proportion of the Cs species was dissolved into the slag phase. In the case of sewage sludge, Cs was calculated to be transformed mostly into crystalline aluminosilicate at incineration temperatures, whereas by analogy with the behaviors of Na and K, Ca,Cs-phosphate double salts were also potential incineration products. These results could account for the high leaching rates of r-Cs from the MSW incineration fly ash and the low leaching rates from the MSW incineration bottom ash and SS incineration fly ash reported in earlier studies. In the case of dewatered SS that included a large amount of slaked lime as a flocculant, it was exceptionally difficult for the calculation to represent the fate of Cs, and we needed to include the contribution of silica sand in a fluidized-bed combustor in the equilibrium calculation to represent the low leaching rates of alkali species from the dewatered SS fly ash. From the results of the thermodynamic equilibrium calculations and also from the calculated standard Gibbs energy of cesium aluminosilicate formation/decomposition reactions, the effects of waste composition and incineration temperature on the fate of Cs were examined: High incineration temperature and large amounts of Ca and Cl in the waste composition increased the fraction of gaseous CsCl in the furnace and thus resulted in the high distribution ratios of Cs in the fly ash of MSW and the high leaching rates of Cs from the fly ash.

CsPbX3 (X = Cl, Br, I) perovskite nanocrystals (NCs) are promising materials due to their excellent optoelectronic properties. This work shows a successful anion exchange reaction in CsPbBr3 nanowire (NW) systems with HCl gas resulting in a blue-green light-emitting CsPbBr3@CsPbBr3-x Cl x core-shell heterojunction. By adjusting the reaction time and the reaction temperature, the structure and light emission of the NWs can be adjusted. The core-shell heterojunction NCs are stably luminescent in 24 h. The rational mechanism of anion exchange in perovskite NCs is also investigated. The work highlights the feasibility of NWs heterogeneously prepared under the HC1 gas atmosphere, which provides a new strategy for studying the two- and multicolor luminescent perovskite NCs.

Adulteration of edible oils by the manufacturers has been found frequently in modern societies. Due to the complexity of the chemical contents in edible oils, it is challenging to quantitatively determine the extent of adulteration and prove the authenticity of edible oils. In this study, a robust and simple MALDI-TOF-MS platform for rapid fingerprinting of triacylglycerols (TAGs) in edible oils was developed, where spectral similarity analysis was performed to quantitatively reveal correlations among edible oils in the chemical level. Specifically, we proposed oil networking, a spectral similarity-based illustration, which enabled reliable classifications of tens of commercial edible oils from vegetable and animal origins. The strategy was superior to traditional multivariate statistics due to its high sensitivity in probing subtle changes in TAG profiles, as further demonstrated by the success in determination of the adulterated lard in a food fraud in Taiwan. Finally, we showed that the platform allowed quantitative assessment of the binary mixture of olive oil and canola oil, which is a common type of olive oil adulteration in the market. Overall, these results suggested a novel strategy for chemical fingerprint-based quality control and authentication of oils in the food industry.

Lower-dimensional metal halide perovskites have been recognized as an efficient white light emitter. The broad band emission spectrum originates from the recombination of excited charge carriers through free excitons (FEs), self-trapped excitons (STEs), and defect-trapped excitons. However, the emission properties of zero-dimensional (0-D) perovskites have not been explored extensively. Here, in this work, we have performed low-temperature absorbance, photoluminescence (PL), PL excitation (PLE), PL lifetime, and Raman measurements to understand the exciton relaxation processes in Cs4PbBr6 NCs. Our experimental observations indicate that two distinct UV light spectra evolved from the photoexcited carrier recombination through FE and STE states. We emphasize that such UV light sources can be beneficial for various applications, like curing of materials, disinfection of viruses, hygiene control, etc.

Inorganic cesium lead triiodide (CsPbI3) perovskite materials are becoming increasingly attractive for use in perovskite/silicon tandem solar cells, due to their almost ideal band gap energy (E g) of about 1.7 eV. To be useful as photovoltaic absorbers, the CsPbI3 must form the cubic or black phase (α-CsPbI3). To do so at relatively low temperatures, hydroiodic acid (HI) is required as a solution additive. This paper demonstrates CsPbI3 perovskite solar cells with an efficiency of 6.44%, formed using a HI concentration of 36 μL/mL. This value is higher than the previous most commonly used HI additive concentration. Herein, by undertaking a systematic study of the HI concentration, we demonstrate that the structural, morphological, optical, and electrical properties of CsPbI3 solar cells, processed with this HI additive concentration, are superior.

Ultrafast charge-transfer (i.e., electron and hole) dynamics has been investigated between the cesium lead bromide (CsPbBr3, CPB) perovskite nanocrystals (NCs) and cadmium selenide (CdSe) quantum dots (QDs) as a new composite material for photocatalytic and photovoltaic applications. The CPB NCs have been synthesized and characterized by high-resolution transmission electron microscopy (HR-TEM) and X-ray diffraction (XRD) pattern. The redox levels (i.e., conduction band (CB) and valence band (VB)) of the CPB NCs and CdSe QDs suggest the feasibility of photoexcited electron transfer from CPB NCs to CdSe QDs and photoexcited hole transfer from CdSe QDs to CPB NCs, and it has been confirmed by both steady-state and time-resolved spectroscopy. To investigate the electron- and hole-transfer dynamics in ultrafast time scale, we have performed femtosecond up-conversion and femtosecond transient absorption studies. The measured electron-transfer time from CPB NCs to CdSe QDs and hole-transfer time from CdSe QDs to CPB NCs were found to be 550 and 750 fs, respectively. Interestingly, the charge-transfer process found to be restricted in CPB/CdSe@CdS core-shell system where electron transfer from CPB NCs to core shell takes place, but the hole transfer from core shell to CPB NCs found to be restricted due to CdS shell making the process thermodynamically nonviable. Our observation has suggested that after the photoexcitation of CPB NCs/CdSe QDs composite system, a charge-separated state is formed where the electrons are localized in CB of CdSe QDs and holes are localized in VB of CPB NCs. This makes the composite system a better material for efficient light harvesting and photocatalytic material as compared to the individual ones.

Upon mass selection and ion activation under mass spectrometric conditions, gaseous formate adducts of many metal formates undergo decarboxylation and form product ions that bear metal-hydrogen bonds. Fortuitously, we noted that negative-ion spectra of several such formate adducts showed many peaks that could not be rationalized by the conventional fragmentation pathways attributed to the precursor ion. Subsequent experimentation proved that these enigmatic peaks are due to an ion-molecule reaction that takes place between traces of adventitious water vapor in the collision gas and the in situ formed product anions bearing metal-hydrogen bonds, generated by the fragmentation of the formate adducts. Results show that metal-hydrogen bonds of the group 2 elements are particularly susceptible to this reaction. For example, in the product-ion spectrum of [Sr(η2-O2CH)3]-, the peak at m/z 91 for SrH3 - was accompanied by three peaks at higher m/z ratios. These peaks, at m/z 107, 123, and 139, represented SrH2(OH)1 -, SrH1(OH)2 -, and Sr(OH)3 -, respectively. These satellite peaks, which were separated by 16 m/z units, were attributed to adducts formed due to the high affinity of gas-phase anions bearing metal-hydrogen bonds to water. Although undesired, these peaks are diagnostically useful to determine the number of metal-hydrogen bonds present in a precursor ion. Even though the peaks were less pronounced, analogous reactions were noted from the adducts of the group 1 elements as well. Moreover, Gibbs free energy values computed for the interaction of [H-Mg(η2-O2CH)2]- with water to form [HO-Mg(η2-OCOH)2]- and H2 indicated that this is an exergonic reaction.

The application of a domino radical bicyclization for the synthesis of compounds containing the 1-azaspiro[4.4]nonane skeleton in 11-67% yields as a mixture of diastereomers is described (trans configuration preference). This process involved formation and capture of alkoxyaminyl radicals. For this purpose, O-benzyl oxime ethers with a brominated or iodinated aromatic ring or a terminal alkynyl group and an alkenyl moiety were employed as starting materials. The bicyclization was initiated by 2,2'-azobisisobutyronitrile or triethylborane and promoted by Bu3SnH. The best results were obtained with O-benzyl oxime ethers containing an alkenyl moiety tethered to electron withdrawing groups or aryl substituents, whereas oxime radical precursor attached to methyl-substituted olefin precluded the capture of alkoxyaminyl radical, giving rise mainly to monocyclized product.

Bisphenol A polycarbonate (BPA-PC) is a remarkable high-performance engineering polymer, although it is susceptible to photo-Fries and hydrolytic degradation. New poly(aryl ether carbonates) were synthesized to address these limitations by replacing the chain backbone carbonate ester functionality with aryl ether functionality. The monomers for these new polymers were synthesized by a variation of the Ullmann condensation accelerated by 2,2,6,6-tetramethylheptane-3,5-dione and promoted by Cs2CO3 and 1-methyl-2-pyrrolidinone under mild conditions. Four such bisphenol A-based diarylether monomers containing different mass ratios of carbonate ester groups were prepared and polymerized with phosgene gas to give novel poly(aryl ether carbonates). Polymers were named as di-o-BPA-PC 9', tri-o-BPA-PC 11', tetra-o-BPA-PC 13', and penta-o-BPA-PC 15' where di-, tri-, tetra-, and penta- reflect the number of diphenylisopropylidene units in each of the respective polymers. The molecular weights of the resulting four poly(aryl ether carbonates) were measured by gel permeation chromatography. Differential scanning calorimetry was used to measure glass transition temperature (T g). The polymers exhibited weight-average molecular weights up to 4.09 × 105 g/mol and T g in the range of 136 to 149 °C with no melting temperature peak, indicative of their amorphous character. The new polymers formed transparent and flexible films by solution casting from chloroform solution.

We used a cesium hexafluorophosphate (CsPF6)-containing liquid electrolyte for surface-patterned Li metal anodes and confirmed that there is a synergistic improvement in the electrochemical performance such as cycle performance and rate capability. For instance, the surface-patterned Li metal maintains 91.4% of the initial discharge capacity after the 1000th cycle (C/2 = 0.8 mA cm-2 for charging, 1C for discharging). When a large quantity of the CsPF6-containing liquid electrolyte (600 μL) is used, the bare Li metal and surface-patterned Li metal are more effectively stabilized in comparison with the case where 80 μL of electrolyte is used, resulting in improved electrochemical performance. Through systematic testing, we recognize that these results are because of the self-healing electrostatic shield mechanism, which is mainly dependent on the amount of Cs+ ions. A small amount of Cs+ ions cannot effectively counteract the incoming Li+ ions because they cannot form an effective electrostatic shield on the protrusions present on the Li metal surface.

Lanthanide-doped upconversion nanoparticles (UCNPs) and cesium lead halide perovskite quantum dots (PeQDs) are highly compatible with each other: UCNPs produce anti-Stokes upconversion luminescence (UCL) under near-infrared (NIR) excitation and the emissive profiles of PeQDs can be conveniently tuned by varying the halide composition ratio. Therefore, in this study, UCNPs and PeQDs are mixed together, producing colorful UCL under 980 nm laser excitation. In addition, ZnI2 is used to vary the halide composition ratio of PeQDs and manipulate UCL in situ, thus adding more flexibility in UCL regulation. Finally, based on the above-mentioned discussion, a double-encrypted anticounterfeiting pattern is generated via sequentially printing ZnI2 solution and UCNP suspension on an A4 paper. Using PeQDs as the decrypting reagent, under the NIR excitation and decryption channel, the hidden information can be fully decrypted. The combination of UCNPs and PeQDs greatly expands the upconversion possibility, offers more feasibility in UCL regulation, and further promotes the practical applications.

Metal-hydride anions of main group elements, such as BaH3 - and InH4 -, were generated by dissociating formate adducts of the respective metal formates. Upon activation, these adducts fragment by formate-ion ejection or by decarboxylation. For adducts of alkali-metal formates, the formate-ion ejection is the preferred pathway, whereas for those of alkaline-earth and group 13-15 metals, the expulsion of CO2 is the more favorable pathway. Decarboxylation is deemed to yield a metal-hydrogen bond presumably by a hydride transfer to the metal atom. For example, the decarboxylation of Al(η-OCOH)4 - and Ga(η-OCOH)4 - generated AlH4 - and GaH4 -, respectively. The initial fragment-ion with a H-M bond formed in this way from adducts of the heavier metals of group 13 (Ga, In, and Tl) undergo a unimolecular reductive elimination, ascribable to the "inert-pair" effect, to lower the metal-ion oxidation state from +3 to +1. As group 13 is descended, the tendency for this reductive elimination process increases. PbH3 -, generated from the formate adduct of lead formate, reductively eliminated H2 to form PbH-, in which Pb is in oxidation state zero. In the energy-minimized structure [H-Pb(η2-H2)]-, proposed as an intermediate for the process, a H2 molecule is coordinated with PbH- as a dihapto ligand. The formate adducts of strontium and barium produce monoleptic ions such as [M(0)(η2-O2CH)1]-, in which the formate ion is chelated to a neutral metal atom. The bismuth formate adduct undergoes a double reductive elimination process whereby the oxidation state of Bi is reduced from +3 to +1 and then to -1. Upon activation, the initially formed [H-Bi-H]- ion transforms to an anionic η2-H2 complex, which eliminates dihydrogen to form the bismuthide anion (Bi-).

Carbon quantum dots (CQDs), a novel fluorescent nanomaterial, have been extensively employed/explored in various applications, that is, biosensors, bioimaging, nanomedicine, therapeutics, photocatalysis, electrocatalysis, energy storage system, and so forth. In this study, we report the synthesis, characterization, and the application of phosphorus-doped CQDs (PCQDs), synthesized using trisodium citrate and phosphoric acid by the hydrothermal method. The effect of phosphorus doping on optical features and the formation of PCQDs have been explored elaborately by controlling the concentrations of precursors, reaction time, and the temperature. The fluorescent quantum yield for PCQDs was determined to be 16.1% at an excitation/emission wavelength of 310/440 nm. Also, the optical and structural properties of PCQDs were determined by using various spectroscopic and microscopic techniques. Static quenching of fluorescence was determined upon the addition of Fe3+ to PCQDs because of the formation of the fluorescent inactive complex (PCQDs-Fe3+). Hence, this chemistry leads to the development of a new fluorometric assay for the detection of Fe3+. The lower limit of Fe3+ detection is determined to be 9.5 nM (3σ/slope), with the linear fit from 20 nM to 3.0 μM (R 2 = 0.99). We have validated this new assay in the raw, ejected, and purified water samples of the RO plant by the standard addition method. These results suggest the possibility of developing a new commercial assay for Fe3+ detection in blood, urine, and various industrial waste and sewage water samples. Furthermore, recycling the pollutant water into the freshwater using filters that consist of PCQDs offers a great deal.

A novel bioorthogonal gold nanoparticle (AuNP) template displaying interfacial nitrone functional groups for bioorthogonal interfacial strain-promoted alkyne-nitrone cycloaddition reactions has been synthesized. These nitrone-AuNPs were characterized in detail using 1H nuclear magnetic resonance spectroscopy, transmission electron microscopy, thermogravimetric analysis, and X-ray photoelectron spectroscopy, and a nanoparticle raw formula was calculated. The ability to control the conjugation of molecules of interest at the molecular level onto the nitrone-AuNP template allowed us to create a novel methodology for the synthesis of AuNP-based radiolabeled probes.

Desalination and nuclide separation, with cesium (Cs), strontium (Sr), and cobalt (Co), using commercial polymeric membranes are investigated under room temperature (298 K) to elucidate the permeation mechanism and possibility of applying commercial membranes to the separation of radioactive nuclides. The physicochemical properties of membranes are characterized by multiple techniques. The thickness of the selective layer and the boundary between the layers of membranes are observed by scanning electron microscopy. The chemical structure of selective and support layers is assessed by direct Fourier transform infrared/attenuated total reflection measurements on membrane samples. Thermogravimetric analysis demonstrates the composition comparison between membranes, which describes the relative amount of selective layers consisting of polyamide. The separation performance of polyamide-based commercial membranes is tested on simulated seawater (35,000 ppm of NaCl) and single- and multi-component aqueous nuclide solutions (10 ppm). Nanofiltration (NF) membranes exhibit a high flux of 160-210 L m-2 h-1 with low 31-64% rejection on the permeation of simulated seawater, while reverse osmosis (RO) membranes display a low flux of 13-22 L m-2 h-1 with nearly 80% rejection. This reveals RO membranes to be more effective for the rejecting nuclides (Cs, Sr, and Co) in dilute aqueous solutions, and NF membranes have advantage on high throughput. RO membranes reject above 93% for single components and even higher for mixed nuclide separation (>98%), and NF membranes permeate high flux above 230 L m-2 h-1. This study indicates that the desalination membranes (NF and RO) can be potential candidates for nuclide separation with combination.