A MELET- and IFE-based UV-visible luminescent ratiometric probe for quantization of mercury(II) and nitrofurantoin in environmental sewage.

A novel fluorimetric ratiometric probe of green and eco-friendily nitrogen-enriched, oxygen-doped carbon nanodots (Cnanodots) was prepared for the quantitative analysis of mercury(II) (Hg) and nitrofurantoin (Nit) in the environmental sewage. The Cnanodots exhibits dual-emission peaks respectively at 345 and 445 nm under 285 nm excitation, with excitation-independent properties. Unexpectedly, this Cnanodots displays two obvious ratiometric responses to Hg and Nit through decreasing the signal at 345 nm and remaining invariable at 445 nm.

Uranyl Affinity between Uranyl Cation and Different Kinds of Monovalent Anions: Density Functional Theory and Quantitative Structure-Property Relationship Model.

In order to design effective extractants for uranium extraction from seawater, it is imperative to acquire a more comprehensive understanding of the bonding properties between the uranyl cation (UO) and various ligands. Therefore, we employed density functional theory to investigate the complexation reactions of UO with 29 different monovalent anions (L), exploring both mono- and bidentate coordination. We proposed a novel concept called "uranyl affinity" () to facilitate the establishment of a standardized scale for assessing the ease or difficulty of coordination bond formation between UO and diverse ligands.

Ion transport through short nanopores modulated by charged exterior surfaces.

Short nanopores find extensive applications, capitalizing on their high throughput and detection resolution. Ionic behaviors through long nanopores are mainly determined by charged inner-pore walls. When pore lengths decrease to sub-200 nm, charged exterior surfaces provide considerable modulation to ion current.

Colorimetric method transforms into highly sensitive homogeneous voltammetric sensing strategy for mercury ion based on mercury-stimulated TiCT MXene nanoribbons@gold nanozyme activity.

Nanozymes were emerged as the next generation of enzyme-mimics which exhibit great applications in various fields, but there is rarely report in the electrochemical detection of heavy metal ions. In this work, TiCT MXene nanoribbons@gold (TiCT MNR@Au) nanohybrid was prepared firstly via a simple self-reduction process and its nanozyme activity was studied. The results showed the peroxidase-like activity of bare TiCT MNR@Au is extremely weak, while in the presence of Hg, the related nanozyme activity is stimulated and improved remarkably, which can easily catalyze oxidation of several colorless substrates (e.

Nitrogen-doped TiC MXene quantum dots as an effective FRET ratio fluorometric probe for sensitive detection of Cu and D-PA.

In this work, a ratiometric fluorescence sensing platform was established to detect Cu and D-PA (d-penicillamine) based on nitrogen-doped TiC MXene quantum dots (N-MODs) that was prepared via a simple hydrothermal method and exhibited strong fluorescent and photoluminescence performance as well as excellent stability. Since the oxidation reaction between o-phenylenediamine (OPD) and Cu induced the formation of 2,3-diaminophenazine (ox-OPD) which not only can emerge an emission peak at 570 nm, but also inhibit the fluorescence intensity of N-MQDs at 450 nm, a ratiometric reverse fluorescence sensor via fluorescence resonance energy transfer (FRET) was designed to sensitively detect Cu, where N-MQDs acted as energy donor and ox-OPD as energy acceptor. More importantly, another considerably interesting phenomenon was that their catalytic oxidation reaction can be restrained in the presence of D-PA because of the coordination of Cu with D-PA, further triggering the obvious changes in ratio fluorescent signal and color, thus a ratiometric fluorescent sensor of determining D-PA was proposed also in this work.

Iodine-doped g-CN modified zinc titanate electron transporting layer for highly efficient perovskite solar cells.

The development of excellent ternary metal oxides as electron transporting layers (ETLs) is highly challenging for perovskite solar cells (PSCs). In this study, ZnTiO (ZTO) nanoparticles are synthesized via a facile sol-gel method, and used as an ETL in PSCs. Furthermore, for the first time, iodine-doped g-CN (ICN) is introduced into ZnTiO-based ETL as additive via a glass-assisted annealing route.

Upon DFT-D3 dispersion correction and ECD spectral confirmation, only several conformers can stably coexist for three fungal cycloaspeptides (A, D, G).

Dispersion correction in theoretical determination of cyclopeptide conformations is emphasized. Whether in gas approximation or in solvation simulation, the density functional theory with London dispersion correction (DFT-D3) demonstrates that only 2-3 conformers can stably coexist for cycloaspeptides (A, D, G) at B3LYP-D3 and CAM-B3LYP-D3. Conformational rationality is confirmed by electronic circular dichroism (ECD).

Robust Mesoporous Functional Hydrogen-Bonded Organic Framework for Hypochlorite Detection.

Although tremendous progress has been achieved in the field of hydrogen-bonded organic frameworks (HOFs), the low stability, small/none pores, and difficult functionality severely obstruct their development. Herein, a novel robust mesoporous HOF (HOF-FAFU-1) decorated with a high density of free hydroxy moieties has been designed and readily synthesized in the synthesis. In HOF-FAFU-1, the planar building blocks are connected to each other by typical intermolecular carboxylate dimers to form two-dimensional (2D) layers with topology, which are further connected to their adjacent layers by face-to-face π-π interactions to obtain a three-dimensional (3D) open mesoporous framework.

Cuttlefish ink loaded polyamidoxime adsorbent with excellent photothermal conversion and antibacterial activity for highly efficient uranium capture from natural seawater.

Owing to the abundant uranium reserves in the oceans, the collection of uranium from seawater has aroused the widespread interest. Compared to the uranium extraction from ore, uranium collection from seawater is a more environmentally friendly strategy. The amidoxime (AO) functional group has been considered as one of the most efficient chelating groups for uranium capture.

Novel Third-Order Nonlinear Optical Materials with Craig-Möbius Aromaticity.

Electron delocalization in aromatic materials significantly impacts their third-order nonlinear optics (NLO). Despite organometallic complexes with Craig-Möbius aromaticity attracting great attention for their unusual physicochemical properties, their third-order NLO have been little studied to date. Herein, 12 Craig-Möbius aromatic organometallics with a stable structure similar to osmapentalyne, namely, carbolong complexes, are screened by DFT.

Tin Metal Cluster Compounds as New Third-Order Nonlinear Optical Materials by Computational Study.

It is quite appealing but challenging to predict and synthesize new nonlinear optical (NLO) materials with exceptional performance. Herein, the different Sn cluster core structures and third-order NLO properties are studied through electronic structure, excited hole-electron, bonding character, and aromaticity analysis. As a result, Sn clusters with ring core structure (Sn-R) not only have the smallest , the largest UV-vis response intensity, but also the strongest third-order NLO response in our work.

A Review of Conductive Carbon Materials for 3D Printing: Materials, Technologies, Properties, and Applications.

Carbon material is widely used and has good electrical and thermal conductivity. It is often used as a filler to endow insulating polymer with electrical and thermal conductivity. Three-dimensional printing technology is an advance in modeling and manufacturing technology.

In situ synthesis of g-CN by glass-assisted annealing route to boost the efficiency of perovskite solar cells.

TiO-based electron transport layers (ETLs) show tremendous advantages in constructing efficient perovskite solar cells (PSCs), but the power conversion efficiency (PCE) needs further improvements. Thus, in this study, graphitic carbon nitride (g-CN), a typical two-dimensional material, was synthesized in-situ and introduced into TiO-based ETLs as an additive via a facile glass-assisted annealing route. The results demonstrated that the addition of g-CN positively influenced the crystalline quality of the perovskite layers, as well as the conductivity and photovoltaic properties of the devices.

Dual-emissive metal-organic framework: a novel turn-on and ratiometric fluorescent sensor for highly efficient and specific detection of hypochlorite.

Hypochlorite (ClO-) is widely used as a disinfectant, whose residue content in water should be strictly controlled due to the potential threat to human health in an inappropriate concentration. Herein, dual-emissive metal-organic frameworks with a UiO-66 prototype structure, PDA/Eu/PDA-UiO-66-NH2(x), were elegantly designed and prepared by a mixed ligand assembly and sequential post-synthesis strategy. Since blue emission is sensitive to ClO-, PDA/Eu/PDA-UiO-66-NH2(40) was selected as a model nanosensor for ratiometric and turn-on sensing of ClO- while red emission acts as a reference signal.

Anion-directed assemblies of europium(III) coordination polymers based on 1H-benzimidazole-5,6-dicarboxylate: structures and luminescence properties.

Two europium(III) coordination polymers (CPs), namely, poly[[diaquabis(μ-1H-benzimidazole-5,6-dicarboxylato-κN:O,O:O,O:O)(μ-oxalato-κO,O:O,O)dieuropium(III)] dihydrate], {[Eu(CHNO)(CO)(HO)]·2HO} (1), and poly[(μ-1H-benzimidazol-3-ium-5,6-dicarboxylato-κO:O,O:O,O)(μ-sulfato-κO:O':O'')europium(III)], [Eu(CHNO)(SO)] (2), have been synthesized via the hydrothermal method and structurally characterized. CP 1 shows a three-dimensional network, in which the oxalate ligand acts as a pillar, while CP 2 has a two-dimensional network based on a europium(III)-sulfate skeleton, further extended into a three-dimensional framework by hydrogen-bonding interactions. The structural diversity in the two compounds can be attributed to the different acidification abilities and geometries of the anionic ligands.

First-principles study of structural stability, electronic and optical properties of GA-doped MAPbI.

Organic-inorganic hybrid halide perovskites have been considered as potential photoconductive materials for photovoltaic applications. Through first-principles calculations, we have investigated the structural stability, electronic and optical properties of GA-doped MAPbI. Our calculated results reveal that 25% GA doping slightly reduce the structural stability of MAPbI.

Computational analysis of non-heme iron-oxo formation by direct NO release in nitrite reduction.

A direct NO-releasing reaction of nitrite catalyzed by [N(afa)Fe(OTf)] (afa (azafulvene-amine); OTf (trifluoromethanesulfonate); Cy (cyclohexyl)) was investigated using density functional theory (DFT) with D3 dispersion correction. The complex featured a secondary coordination sphere that facilitated the formation of the iron-oxo product [N(afa)FeO] with three (Fe)OH-N hydrogen bonds. As a high-spin iron(ii), the O-binding initial intermediate Fe(O)-nitrito was thermodynamically favorable in the S = 2 state.

Ethylammonium as an alternative cation for efficient perovskite solar cells from first-principles calculations.

Mixed-cation lead halide perovskites have emerged as a new class of promising photovoltaic materials for perovskite solar cells. Formamidinium (FA), methylammonium (MA), and Cs cations are widely studied in the field of mixed-cation hybrid halide perovskites. In this work, we have investigated ethylammonium (CHCHNH, EA) as an alternative cation to explore the stabilities and electronic properties of mixed MA EA PbI perovskites.

Pressure-induced effects in the inorganic halide perovskite CsGeI.

Perovskite photovoltaic materials are gaining significant attention due to their excellent photovoltaic properties. In this study, density functional theory calculations were performed to investigate the structure and electronic and optical properties of CsGeI under hydrostatic strain. The results show that the band gap of CsGeI can be tuned from 0.

Synergistic Effect of Doping and Compositing on Photocatalytic Efficiency: A Case Study of LaTiO.

Charge generation and separation are two key issues in developing a high-efficiency semiconductor for the visible-light-driven photocatalysis. Here, we use the layered perovskite-type wide-gap semiconductor LaTiO (LTO) as a model to systematically explore the synergistic effect of doping (with sulfur or nitrogen) and heterojunction (with graphitic CN) on improving visible light absorption and photoexcited charge separation by means of density functional theory calculations. It is found that the anion (N or S) doping into the LTO(010) surface can not only shift the optical absorption edge to the visible region, but also creates some partially occupied or unoccupied states in the band gap that would facilitate the formation of recombination centers.

A highly hydrolytically stable lanthanide organic framework as a sensitive luminescent probe for DBP and chlorpyrifos detection.

Organic pollutants have attracted increasing attention due to their strong persistence and extensive diffusivity. Plasticizers (PAEs) and organophosphorus pesticides (OPs), as the vital part of organic pollutants, have made extensive damage to the environment with the rapid development of modern agriculture and industry. Therefore, we have, for the first time, carried out a quantitative analysis of the PAEs and OPs by fluorescence recognition.

Two-Dimensional Deep-Ultraviolet Beryllium-Free KBeBOF Family Nonlinear-Optical Monolayer.

A two-dimensional (2D) nonlinear-optical (NLO) material could generate a breakthrough in the development of a nanoscale laser, especially in the range of high-energy and short-wavelength deep ultraviolet (DUV; <200 nm). KBeBOF (KBBF) is the only bulk crystal actually used in the DUV region. In this letter, we designed the new 2D KBBF family monolayer AlLiBOF (2D-ALBF), which was predicted to have a broad DUV-vis transparent range and an enhanced NLO effect that doubles the frequency.

Thickness-controlled electronic structure and thermoelectric performance of ultrathin SnS2 nanosheets.

The thermoelectric conversion efficiency of a material relies on a dimensionless parameter (ZT = S σT/κ). It is a great challenge in enhancing the ZT value basically due to that the related transport factors of most of the bulk materials are inter-conditioned to each other, making it very difficult to simultaneously optimize these parameters. In this report, the negative correlation between power factor and thermal conductivity of nano-scaled SnS multilayers is predicted by high-level first-principle computations combined with Boltzmann transport theory.

Theoretical perspectives on the structure, electronic, and optical properties of titanosilicates LiM[(TiO)SiO] (M = K, Rb).

It is still a challenge to design and synthesize high performance broader ultraviolet non-linear optical (NLO) materials. Two new transition-metal silicates have recently attracted a lot of attention due to their strong phase-matched second harmonic generation (SHG) responses (about 4.5 times higher than KDP).

A promising lead-free fluoride carbonate SHG material designed from a theoretical perspective.

In recent years, a series of fluoride carbonate crystals, as second harmonic generation (SHG) materials, have been considerably developed; however the lead in these materials is a potential threat to the environment. In this study, the structure, mechanical and optical properties of ABCOF (A = Rb, Cs; B = Ge, Sn) were systematically investigated to find alternatives to APbCOF. We found that the RbSnCOF crystal displays substantial stability and remarkable linear optical properties compared with those of the lead fluoride carbonate SHG materials.