Solvent Atmosphere Research Articles

Mixed solvent atmosphere induces the surface termination state transition of perovskite to achieve matched energy level alignment

The optimal alignment of semiconductor's electronic energy level with respect to hole-transporting materials (HTMs and ETMs) determines the photovoltaic conversion efficiency of perovskite solar cells (PSCs). The energy level of perovskite can be greatly affected by the crystal surface termination state formed in the perovskite polycrystalline film preparation process. Perovskite featured with Pb-X termination always bears deep energy level which cannot match well HTM. Herein, to regulate the surface termination state of the perovskite crystals, a controlled solvent atmosphere dimethyl sulfoxide (DMSO) and N,N-dimethylformamide (DMF) was employed to induce the regrowth of perovskite crystals. Results prove that the mixed solvent of DMSO and DMF can induce perovskite crystals from Pb-X termination to A-X termination. Density functional theory (DFT) calculations show that the terminated conversion moves the valence and conduction band edge (VBE and CBE) of perovskite crystal to a shallower energy level, which does great favor to match the energy level of HTM, and then contributes to extracting charges. In addition, the defect density of the optimized perovskite polycrystalline film decreased from 1.258 × 1016 to 1.022 × 1016 cm -3, and the depletion width of PSCs increased from 48.9 to 56.1 nm. Profiting from the effective charge extraction and reduced non-radiative recombination, the open circuit voltage of the PSC increased from 0.99 to 1.09 V, and the conversion efficiency boosted from 17.8% to 20.3%..

Promoting electron transfer of surface oxygen vacancies in Pd/CeO2-RE via doping engineering for enhancing catalytic activity in Suzuki coupling reaction

Doping engineering is considered as a facile and effective method for improving the physical and chemical properties of CeO2. Herein, rare earth (RE) ions (La and Nd) doped Pd/CeO2 with the coaxial double-nanotube structure were manufactured by the electrospinning and high-temperature calcination. Through the doping engineering, the original morphologies of Pd/CeO2 were not destroyed and all the elements were uniformly distributed on the surface of nanotubes. XRD, Raman and UV–vis characterizations revealed that La3+ and Nd3+ ions were incorporated into the CeO2 lattice, while the cubic fluorite structure of CeO2 was maintained. Moreover, it has been proved that there were oxygen vacancies existed on the surface of CeO2 and the concentration of oxygen vacancies increased significantly as the radius of RE ions increases. In addition, an electron transfer pathway between CeO2 and Pd nanoparticles was proposed based on the experimental data and Density Functional Theory (DFT) calculations. The Pd/CeO2-La catalyst with abundant oxygen vacancies showed a high catalytic performance for Suzuki coupling reaction under mild conditions without any phase-transfer reagent, toxic solvent and inert protective atmosphere, which realizing the green catalysis.

Structural (monomer and dimer), wavefunctional, NCI analysis in aqueous phase, electronic and excited state properties in different solvent atmosphere of 3-{(E)-[(3,4-dichlorophenyl)imino]methyl} benzene-1,2-diol

In this present work, structural, wave functional and electronic properties of 3-{(E)-[-(3,4-dichlorophenyl)imino]methyl}benzene-1,2-diol are investigated by utilizing Gaussian 16W density functional theory tool. Optimized geometrical properties, wave functional properties like, localized orbital locators, electron localization functions and reduced density gradient are examined in aqueous phase. Band gap energies with solvation effect are calculated from HOMO-LUMO orbital’s with different solvent molecules. Reactive sites are identified from MEP analysis in various solutions. Excited energies are calculated using TD-DFT method in different polar and non polar liquids. Intra molecular and intermolecular interactions are studied by NBO method to explain the charge transfer within the molecules. Spectroscopic (IR and Raman) wave numbers for headline compound are predicted computationally in monomer and dimer form. Moreover, adsorption, metabolism, excretion, distribution with toxicity are computed. Finally, to find biological and anticancer activities of title compound molecular docking study is performed.

Preparation and Self-Assembling of PLA-b-PNIPAM-b-PS Triblock Copolymer Thin Films.

Polylactide-b-poly(N-isopropylacrylamide)-b-polystyrene (PLA-b-PNIPAM-b-PS) triblock copolymers (tri-BCPs) with various chemical compositions (block ratio) were prepared from the combination of ring-opening polymerization and reversible addition-fragmentation chain transfer polymerization. Subsequently, the self-assembling behaviors of these tri-BCP films obtained from spin-coating were investigated by annealing them under different solvent atmosphere. We found that these films could self-assemble into various morphologies due to the microphase separation of incompatible copolymer blocks. Atomic force microscopy confirmed the perpendicular cylindrical morphology self-assembled from PLA4.5k-b-PNIPAM5.2k-b-PS22.4k tri-BCP film under mixed solvent atmosphere of toluene/acetone (7:3, v/v). Self-assembled PLA cylinders are evenly distributed among the PS matrix and perpendicular to the film surface, with PNIPAM component taking place at the PLA/PS interphase. Furthermore, by etching the degradable PLA component, porous PS film decorated with PNIPAM "brushes" hoisting channels were generated. This work provides a facile method and detailed protocol for fabricating stimuli-responsive porous films which are promising for thermoresponsive "smart" separation technologies.

Structural, physico-chemical landscapes, ground state and excited state properties in different solvent atmosphere of Avapritinib and its ultrasensitive detection using SERS/GERS on self-assembly formation with graphene quantum dots

Avapritinib is a complex molecule with many heterocyclic rings developed for the treatment of advanced PDGFRA D842V-mutant gastrointestinal stromal tumours. The manuscripts presents the study of the structure, ground state and excited state reactivity and stability indices in different solvent atmosphere using density functional theory in B3LYP/aug-cc-pVDZ level. Different molecular properties like reactivity surface, average local ionization energy, nuclear and electronic electrostatic potential, reduced density gradient assay, and localized molecular orbital analysis are studied in detail. The various intramolecular electron delocalisations were studied using natural orbital formalism and intermolecular interactions analysed by evaluating the extended of non-covalent interactions. Another interesting study is the enhancement in Raman activity of the compound when it forms a self-assembly with graphene quantum dots leading to SERS/GERS, which is studied by incorporating Grimme's dispersion into the previous functional. The electronic spectrum was studied in detail using time dependent density functional theory using long range corrected CAM-B3LYP functionals. The compound showed good light harvesting efficiency also. The local information entropy study provides uncertainty of electrons in spatial distribution.

Detailed spectra, electronic properties, qualitative non-covalent interaction analysis, solvatochromism, docking and molecular dynamics simulations in different solvent atmosphere of cenobamate

Cenobamate, which is a voltage-gated sodium channel (VGSC) blocker, finds its full application in several anti-epileptic medications. This manuscript tries to look at the structure and other physicochemical properties of this compound with electronic structure methods and molecular mechanics tools. Density functional theory was used to optimise the ground-state geometry of the molecule using dispersion-corrected ω-B97XD functional using aug-cc-pVDZ basis sets, from which frontier molecular orbitals were studied. This study gave a myriad of information about the electronic properties and descriptors that are well enough to predict the bioactivity of the molecule. Electronic excitations between different energy levels, resulting from the interaction between the electrons and electromagnetic radiation, were analysed using time-dependent density functional theory with CAM-B3LYP functional. Numerous parameters like Fukui, ALIE and MESP provided an ample amount of information about the reactivity preferences of the molecule. Molecular docking studies predicted the biological activity of the molecule and its possible use as an anti-depressant. As it was found to show biological activity, its liquid-state behaviour in different solvents was mapped using molecular dynamics simulations.

Efficient Thiophene Synthesis Mediated by 1,3‐Bis(carboxymethyl)imidazolium Chloride: C‐C and C‐S Bond Formation

Thiophene derivatives have been prepared by means of a functionalized imidazolium salt [1,3‐bis(carboxymethyl)imidazolium chloride] acting as a catalyst. The heterogeneous catalyst has allowed to carry out the reactions with no solvent or inert atmosphere. Different aryl methyl ketones have reacted with elemental sulfur to selective produce 2,4‐substituted thiophenes. Furthermore, the reaction of sulfur with cyclic ketones has enabled the preparation of polycyclic compounds. This protocol is simple and effective for preparing thiophene derivatives, even in a preparative scale. The thiophene synthesis described presents remarkable sustainability with an E‐factor of 7.4, the solvent‐free conditions being crucial for this feature. The catalyst is straightforwardly prepared, and it is easily separated from the reaction mixture, making its reuse possible.

Developments in Colloidal Synthesis of Cu2-xS (0 ≤ x ≤ 1) Nanocrystals—An Overview

Colloidal synthesis of Cu2-xS (x = 0 ≤ x ≤ 1) nanocrystals (NCs) has been developed in recent years as broad context and its applications for energy harvesting is widely analyzed. Exciting properties of Cu2-xS NCs such as cation exchange, localized surface plasmon resonance (LSPR) in near infra-red (NIR) region are well manipulated by altering the stoichiometry through facile colloidal method. Due to their size, shape, phase tunability and self-assembly nature, synthesis of Cu2-xS NCs through colloidal medium has many advantages. Desired phase with desired composition can be achieved through facile tuning of solvent atmosphere and physical parameters of the synthesis conditions. In this regard, the present review summarizes recent achievements made in the colloidal synthesis of Cu2-xS NCs. Their structural and phase transformation in presence of different solvents and reaction conditions have been reviewed. The crucial role of phosphine-free solvents in synthesizing various phases, morphology of Cu2-xS NCs has been discussed. Applications of these Cu2-xS NCs for solar energy harvesting in third generation solar cells have also been reviewed.

Enhancement of Novolac aerogel nanostructure and cellulose cork on thermal performance and ablation properties of lightweight heat shields: with regard to omission of thermal convection

ABSTRACT In order to study heat transfer in cellulose cork, Novolac aerogel with features including large surface area and low-thermal conductivity was used as filler. Novolac colloids result in cork micropores packing and minimize convection heat transfer. Novolac aerogel was synthesized through sol–gel at saturated vapor of solvent atmosphere. A small amount of Novolac enables cork nanocomposites to have low-thermal conductivity, diffusivity, and high-thermal stability (reduction about 39%, 45%, and improvement of 30°C, respectively). Ultimately, in order to improve aerogel/cellulose cork nanocomposites ablation, samples have been coated with resole resin-filled graphene oxide.

Co-liquefaction of Xilinguole lignite and lignin in ethanol/water solvents under a cheap iron ore catalyst

The co-liquefactions of Xilinguole lignite (XL) and lignin in ethanol/water solvents were carried out at N2 atmosphere, and the effect of an in-situ H2-reduced hematite ore catalyst was also discussed in this study. Ethanol-water (50:50, v/v) mixed solvent gave a high liquefaction conversion of 45.7 wt%, but the oil yield was low as 14.9 wt% in the co-liquefaction of XL and lignin at 360 °C, 60 min and N2 atmosphere. Ethanol was a better solvent than ethanol-water (50:50, v/v) mixed solvent; it achieved both high of 44.3 wt% liquefaction conversion and 31.3 wt% oil yield in the same co-liquefaction condition. Formic acid could supply in-situ active H in the co-liquefaction of XL and lignin in ethanol/water solvents, and promoted the liquefaction conversion and oil yield. Addition of 10 v% formic acid in ethanol, the liquefaction conversion and oil yield further increased from 44.3 and 31.3 wt% (without formic acid) to 53.3 and 37.7 wt%, respectively in the co-liquefaction of XL and lignin at 360 °C, 60 min and N2 atmosphere. There existed a synergistic effect in the co-liquefaction of XL and lignin, and the synergistic effect was further promoted by the in-situ H2-reduced hematite ore catalyst. The oil yield increased from 34.5% without ore catalyst, to 48.7% under the ore catalyst, with the increments of 13.8% in the co-liquefaction of XL and lignin at 400 °C with ethanol as solvent and N2 atmosphere. The characterization of co-liquefaction products suggested that the in-situ H2-reduced hematite ore catalyst promoted more heavy constituents of XL converting into oil fraction, thus dramatically promoting the synergistic effect.

Effect of Preparation Solvent and Calcination Atmosphere on Ni@SiO2 Catalyst for Simultaneous Production of Hydrogen and Carbon Nanotubes from Simulated Plastic Waste Syngas

SiO2 core supports are prepared via the Stöber method with various synthesizing solvents. Then, a Ni shell is deposited on SiO2 by a deposition–precipitation method. The results illustrate that using isopropanol as the solvent governs the catalyst particle size with a superior dispersion and a high catalytic activity. Thus, the calcination atmosphere of the catalyst directly affects both the chemical state and the catalytic performance of the active sites. The Ni@SiO2‐I‐air (isopropanol) catalyst calcined by air with more Ni2+ facilitates the highest H2 production of 142.2 mmol g−1 h−1 but provides a carbon nanotube (CNT) yield of only 7.6%. Most importantly, the Ni@SiO2‐I‐H2 catalyst calcined by ambient H2 is prone to form Ni0 species, thus providing the best crystalline conversion and metal–support interaction, which benefits the production of CNTs to a maximum yield of 19.8% with a H2 production of 122.8 mmol g−1 h−1.

Solvent and Substituents Effect on the UV/Vis Absorption Spectra of Novel Acidochromic 2-Aminothiazole Based Disperse Mono Azo Dyes

The effect of solvent atmosphere on the electronic absorption properties of 2-aminothiazole based monoazo disperse dyes are studied. The synthesized monoazo dyes with different substituents on the para position of phenyl ring led to changes in the absorption properties of these dyes. Further, the positive solvatochromism data was evaluated to get the excited and ground state dipole moment ratio of the dyes. The Kamlet-Taft and Catalan polarity scales were employed wherein the solvent basicity and dipolarity is responsible for the bathochromic shift with increase in solvent polarity. The free amino group in the dyes made it responsive towards protonation by trifluoroacetic acid. The acidochromic behavior of the dyes was studied and D1, D3, and D4 exhibited major color change to longer wavelength with emergence of a new red shifted absorption band at 556 nm, 580 nm, and 540 nm, respectively, in their absorption spectra. Thus with help of simple UV-Vis absorption studies, we have studied the intermolecular interactions of the 2-aminothiazole based mono azo acidochromic probe.

Synthesis of Benzoxazoles, Benzimidazoles, and Benzothiazoles Using a Brønsted Acidic Ionic Liquid Gel as an Efficient Heterogeneous Catalyst under a Solvent-Free Condition.

Herein, we introduce a reusable Brønsted acidic ionic liquid gel (BAIL gel) obtained by treating 1-methyl-3-(4-sulfobutyl)-1H-imidazolium hydrogen sulfate with tetraethyl orthosilicate (TEOS). The grafting of the Brønsted acidic ionic liquid to the surface of TEOS has increased the catalytic activity of the material and also simplified catalyst recovery from the reaction mixture. This reaction has a wide substrate scope, and the BAIL gel represents a new catalyst for the synthesis of benzoxazoles, benzimidazoles, and benzothiazoles. The method shows attractive characteristics such as high yields, recyclable catalyst, and work-up simplicity. More importantly, no additional additives or volatile organic solvent and inert atmosphere are required for the reaction, and the BAIL gel has shown a great promise for industrial applications. To the best of our knowledge, the synthesis of benzoxazoles, benzimidazoles, and benzothiazoles using a recyclable heterogeneous ionic liquid gel was not previously reported in the literature.

Generation of twisted nanowires with achiral organic amphiphilic copper complexes.

Drying under solvent atmosphere (DUSA) was investigated as an experimental technique to generate self-assembled nanowires and needles from solutions of organic molecules under controlled conditions. Experimental observations of twisted nanowires are reported. These twisted nanowires were obtained by drying of solutions of achiral molecules under solvent controlled atmospheres: achiral, amphiphilic copper complexes were dissolved in an achiral solvent and these solutions were dried under controlled conditions. Two structurally related copper complexes were investigated. Microscopic investigations of the resulting nanowires revealed, and scanning electron microscopy confirmed: self-assembled twisted ribbons could be selectively obtained from one of these compounds. This behavior could be explained by comparing the ratio of the size of the head group and the overall length of the molecules. The occurrence of chiral filaments and chiral phases of nanosegregated filaments are rare in achiral compounds. The occurance of such twisted filaments is thought to be related to symmetry-breaking during a phase transition from liquid crystalline or lyotropic liquid crystalline phases to a nanosegregated phase. In the reported experiments, the concentration of a solution was gradually increased until crystallization occurred. The results clearly show how DUSA can be applied to investigate the capability of achiral substances to yield twisted filaments. Moreover, the investigated compounds had high-enough charge carrier mobilities, such that the twisted filaments obtained are candidates for self-assembled, intrinsically coiled nano-inductivities.

Four solid forms of filgotinib hydrochloride: Insight into the crystal structures, properties, stability, and solid-state transitions

Four solid forms of filgotinib hydrochloride were introduced in this study, including form A (trihydrate), form B (DMF solvate), form C (DMSO-water solvate) and form D (anhydrate). Single-crystal structures of the three pseudopolymorphs were elucidated by single-crystal X-ray diffraction. The results show that both form B and C are crystallized in the P‾1 space group with similar packing arrangement, while form A is in the P21/n space group. The host molecule conformations, H-bonding interactions, and packing arrangements of these single crystals were analyzed also. Besides, Hirshfeld surface analysis were used to compare the intermolecular interactions in these crystal structures. The properties of these solid forms were fully characterized by powder X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis and Fourier transform infrared spectroscopy. The transformation relationship and the solid-state stability of all forms under different conditions were examined. Form A is proved to be the most stable form under normal storage conditions. However, solid-state transition experiment shows that it would transform to the corresponding solvate form under specific solvent atmosphere.

Convenient fabrication of conjugated polymer semiconductor nanotubes and their application in organic electronics.

Organic heterojunction is indispensable in organic electronic devices, such as organic solar cells, organic light-emitting diodes and so on. Fabrication of core–shell nanostructure provides a feasible and novel way to prepare organic heterojunction, which is beneficial for miniaturization and integration of organic electronic devices. Fabrication of nanotubes which constitute the core–shell structure in large quantity is the key for the realization of application. In this work, a simple and convenient method to prepare nanotubes using conjugated copolymer of perylene diimide and dithienothiophene (P(PDI-DTT)) was demonstrated. The relationship between preparation conditions (solvent atmosphere, solution concentration and pore diameter of templates) and morphology of nanostructure was studied systematically. P(PDI-DTT) nanotubes could be fabricated in regular shape and large quantity by preparing the solution with appropriate concentration and placing anodic aluminium oxide template with nanopore diameter of 200 nm in the solvent atmosphere. The tubular structure was confirmed by scanning electron microscopy. P(PDI-DTT) nanotubes exhibited electron mobility of 0.02 cm2 V–1 s–1 in field-effect transistors under ambient condition. Light-emitting nanostructures were successfully fabricated by incorporating tetraphenylethylene into polymer nanotubes.

Morphology-controlled self-assembled nanostructures of an organic emitter based on an aromatic amino compound

Here we show the fabrication of the morphology-controlled self-assembled nanostructures based on the aromatic emitter dimethyl 2,5-bis((perfluorophenyl)amino)terephthalate (DPPAT) by using the drying under solvent atmosphere method. The experimental results indicate one-dimensional nanowires with high aspect ratio. Moreover, the corresponding nanostructures are strongly dependent on the experimental conditions such as concentration, applied volume and solvent atmosphere. In our case, wire growth seems to be favorable under solvent atmospheres with a high vapor pressure, while the polarity of the used solvent does not have a significant influence. Furthermore, flexible and thin wires can be fabricated with acetone, hexane and chloroform as the solvent atmosphere.

Role of hydrogen donor and non-donor binary solvents in product distribution and hydrogen consumption during direct coal liquefaction

Direct liquefaction of Chinese Hami sub-bituminous coal was conducted with binary mixtures of hydrogen donor solvent tetralin (THN) and non-donor 1-methylnaphthalene (1-MN) or naphthalene (Nap.). Effects of solvent composition, temperature, atmosphere, and catalyst FeS2 on product distribution and hydrogen consumption were investigated at solvent/coal mass ratio of 2. The results show that oil yield increases from 47.70% to 59.95% with 1-MN/THN ratio changing from 2:1 to 1:2. Hydrogen donating ability of binary solvents increases with the rising ratio of THN. H2 contributes noticeably positive effect on coal conversion in the case of liquefaction with insufficient hydrogen donor solvent. Oil yield obtained during direct coal liquefaction (DCL) with Nap./THN is 58.32%, which is 10.62% higher than that with 1-MN/THN at same solvent ratio of 2:1. This is owing to demethylation effect of 1-MN under liquefaction condition. 1-MN demethylation is induced by active hydrogen and coal radicals, and could consume noticeable hydrogen during DCL. This indicates that the amount of alkylarenes included in liquefaction mixed solvents should be limited, or sufficient hydrogen donor solvent is required to achieve high coal conversion.

In Situ Real-Time Study of the Dynamic Formation and Conversion Processes of Metal Halide Perovskite Films.

Metal halide perovskite solar cells (PSCs) have advanced to the forefront of solution-processed photovoltaic techniques and made stunning progress in power conversion efficiency (PCE). Further improvements in device performances rely on perfecting the structure and morphology of perovskite films. However, undesirable defects such as pinholes and grain boundaries are often created in film preparations due to lack of knowledge of the precise reaction mechanism. Here, in situ grazing-incidence X-ray diffraction (GI-XRD) investigations are performed, facilitated by other techniques, on the formation of the widely adopted MAPbI3 (MA = methylammonium) perovskite films from their intermediate adduct (IA) phases. The influences of solvent vapor atmospheres on MAPbI3 films are also systematically investigated, where the dynamic conversion processes between different phases are visualized in real time. Further in situ GI-XRD and infrared spectroscopy measurements reveal that the IA phases contain both N,N-dimethylformamide and dimethyl sulfoxide (DMSO) as coordinating molecules. By tuning the DMSO concentration in perovskite precursors, the ideal perovskite film is formed and the best PCE is achieved for the planar MAPbI3 -based PSCs. These findings highlight the role of IA phases and the effect of solvent atmospheres on the quality of perovskite films, providing direct insights into their growth mechanism.

Die Bonding Performance Using Bimodal Cu Particle Paste Under Different Sintering Atmospheres

A one-step polyol method was employed to synthesize bimodal Cu particles with average diameters around 200 nm and 1000 nm, respectively. The bimodal Cu particles were mixed with a reductive solvent of polyethylene glycol (PEG) to form a paste. The Cu paste was used as die bonding material to prepare Cu joints under N2 or vacuum sintering atmosphere. The results showed that the strength of the Cu joints in N2 atmosphere was always higher than that in vacuum. The shear strength of a Cu joint processed at 350°C under only 0.4 MPa bonding pressure in N2 was above 40 MPa, which was far higher than that obtained using single-sized nano-Cu particle paste. It is related to the dense packing of the bimodal Cu particles and slow decomposition behavior of the reductive PEG solvent. The reductive PEG solvent in the Cu paste, which effectively removed oxides on the surface of the Cu particles, was necessary for easy-oxidized Cu pastes. These results suggested that Cu pastes with suitable particle sizes, reducing solvent and sintering atmosphere could be a proper candidate for low-temperature and low-pressure bonding process.