The controllable growth of CsPbI3 perovskite thin films with desired crystal phase and morphology is crucial for the development of high efficiency inorganic perovskite solar cells (PSCs). The role ...of dimethylammonium iodide (DMAI) used in CsPbI3 perovskite fabrication was carefully investigated. We demonstrated that the DMAI is an effective volatile additive to manipulate the crystallization process of CsPbI3 inorganic perovskite films with different crystal phases and morphologies. The thermogravimetric analysis results indicated that the sublimation of DMAI is sensitive to moisture, and a proper atmosphere is helpful for the DMAI removal. The time‐of‐flight secondary ion mass spectrometry and nuclear magnetic resonance results confirmed that the DMAI additive would not alloy into the crystal lattice of CsPbI3 perovskite. Moreover, the DMAI residues in CsPbI3 perovskite can deteriorate the photovoltaic performance and stability. Finally, the PSCs based on phenyltrimethylammonium chloride passivated CsPbI3 inorganic perovskite achieved a record champion efficiency up to 19.03 %.
The role of DMAI in fabricating high quality CsPbI3 inorganic perovskite thin films is demonstrated to be a volatile crystal growth additive rather than dopant. With optimal DMAI additive and PTACl passivation, a PTACl‐CsPbI3 based champion photovoltaic device exhibits a record efficiency of 19.03 %.
Recent efforts and progress in unraveling the fundamental mechanism of excitation energy migration dynamics in upconversion nanomaterials are covered in this review, including short- and long-term ...interactions and other interactions in homogeneous and heterogeneous nanostructures. Comprehension of the role of spatial confinement in excitation energy migration processes is updated. Problems and challenges are also addressed.
Excitation energy migration in a rare earth ions doped upconversion nanoparticle.
Cellulose is one of the most abundant bio-renewable materials on the earth and its conversion to biofuels provides an appealing way to satisfy the increasing global energy demand. However, before ...carrying out the process of enzymolysis to glucose or polysaccharides, cellulose needs to be pretreated to overcome its recalcitrance. In recent years, a variety of ionic liquids (ILs) have been found to be effective solvents for cellulose, providing a new, feasible pretreatment strategy. A lot of experimental and computational studies have been carried out to investigate the dissolution mechanism. However, many details are not fully understood, which highlights the necessity to overview the current knowledge of cellulose dissolution and identify the research trend in the future. This perspective summarizes the mechanistic studies and microscopic insights of cellulose dissolution in ILs. Recent investigations of the synergistic effect of cations/anions and the distinctive structural changes of cellulose microfibril in ILs are also reviewed. Besides, understanding the factors controlling the dissolution process, such as the structure of anions/cations, viscosity of ILs, pretreatment temperature, heating rate,
etc.
, has been discussed from a structural and physicochemical viewpoint. At the end, the existing problems are discussed and future prospects are given. We hope this article would be helpful for deeper understanding of the cellulose dissolution process in ILs and the rational design of more efficient and recyclable ILs.
This perspective summarizes mechanistic studies on cellulose dissolution in ionic liquids, highlighting the synergistic mechanism, physicochemical aspects and future research trends.
•The multi-objective optimization method is developed for thermal-fluid problems.•Pareto-optimal solutions based on the multi-objective function are provided.•A novel model for heat transfer ...enhancement and pressure drop reduction.•The influence of non-Newtonian fluid on the microchannel heat transfer system is considered.
This paper presents a multi-objective topology optimization method for convective heat transfer problems based on Navier-Stokes and heat transport equations. In this research, the pressure drop (or energy dissipation) function and the recoverable thermal power function are combined and optimized as a multi-objective function. A Pareto algorithm is constructed, based on a weighted-sum method using different weight coefficients. The Pareto solutions composed of a set of optimal solutions are obtained to reveal the trade-off relationship between the objective functions. The effects of non-Newtonian fluid on the flow-channel arrangement and heat transfer performance are numerically studied. In the numerical method, the interpolation term in the density-based topology optimization method is modified, while the filtering method is used to solve the problems of grayscale and the flow channel discontinuity. The results show that the differences between the optimal structures for non-Newtonian fluid and Newtonian fluid are more obvious at Re = 0.01 in the dual-terminal devices. Under the same situation, blood (non-Newtonian fluid) has greater energy dissipation and better heat transfer performance than water (Newtonian fluid).
An efficient, mild and redox‐neutral iridium(III)‐catalyzed C−H annulation of N‐phenoxyacetamides for the regioselective synthesis of benzofurans has been developed by employing tertiary propargyl ...alcohols as the versatile coupling partners. The computed results together with the experimental data revealed that the hydroxyl group of tertiary propargyl alcohols acts as the key factor in controlling the regioselectivity and tuning the reactivity.
Herein, multiple types of chiral Os(II) complexes have been designed to address the appealing yet challenging asymmetric C(sp3)−H functionalization, among which the Os(II)/Salox species is found to ...be the most efficient for precise stereocontrol in realizing the asymmetric C(sp3)−H amidation. As exemplified by the enantioenriched pyrrolidinone synthesis, such tailored Os(II)/Salox catalyst efficiently enables an intramolecular site‐/enantioselective C(sp3)−H amidation in the γ‐position of dioxazolone substrates, in which benzyl, propargyl and allyl groups bearing various substituted forms are well compatible, affording the corresponding chiral γ‐lactam products with good er values (up to 99 : 1) and diverse functionality (>35 examples). The unique performance advantage of the developed chiral Os(II)/Salox system in terms of the catalytic energy profile and the chiral induction has been further clarified by integrated experimental and computational studies.
Based on a computer‐aided ligand design, the first chiral Os(II)/Salox catalytic system is realized to address the appealing yet challenging asymmetric γ‐C(sp3)−H amidation of dioxazolones with precise site‐/enantioselectivity control and diverse functionality. The catalytic energy profile and the chiral induction mode of the developed chiral Os(II)/Salox system are also further clarified by integrated experimental and computational studies.
Lung cancer is a leading cause of cancer mortality worldwide. In tumors, the important role of noncoding RNA regulatory networks has been more and more reveal. EGFR has been identified as an ...oncogenic driver of NSCLC, especially activating mutations EGFR and its inhibition with specific TKIs can generate dramatic tumor responses. Studies have shown that EGFR plays significant roles in the progression of NSCLC. Subset analysis of the small proportion of patients with EGFR-mutant lung cancer showed a disease-free survival benefit, but was underpowered to detect a survival advantage. Herein, we highlight the progression of EGFR, noncoding RNA, and their roles in carcinogenesis. We also focus on anti-lung cancer drug development and EGFR-related drug resistance.
Chloroplasts are the organelles that perform energy transformation in plants. The normal physiological functions of chloroplasts are essential for plant growth and development. Chilling is a common ...environmental stress in nature that can directly affect the physiological functions of chloroplasts. First, chilling can change the lipid membrane state and enzyme activities in chloroplasts. Then, the efficiency of photosynthesis declines, and excess reactive oxygen species (ROS) are produced. On one hand, excess ROS can damage the chloroplast lipid membrane; on the other hand, ROS also represent a stress signal that can alter gene expression in both the chloroplast and nucleus to help regenerate damaged proteins, regulate lipid homeostasis, and promote plant adaptation to low temperatures. Furthermore, plants assume abnormal morphology, including chlorosis and growth retardation, with some even exhibiting severe necrosis under chilling stress. Here, we review the response of chloroplasts to low temperatures and focus on photosynthesis, redox regulation, lipid homeostasis, and chloroplast development to elucidate the processes involved in plant responses and adaptation to chilling stress.
Recently, it has been reported that addition of a cosolvent significantly influences solubility of cellulose in ionic liquids (ILs), but little is known about the influence mechanism of the cosolvent ...on the molecular level. In this work, four kinds of typical molecular solvents (dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), CH3OH, and H2O) were used to investigate the effect of cosolvents on cellulose dissolution in C4mimCH3COO by molecular dynamics simulations and quantum chemistry calculations. It was found that dissolution of cellulose in IL/cosolvent systems is mainly determined by the hydrogen bond interactions between CH3COO− anions and the hydroxyl protons of cellulose. The effect of cosolvents on the solubility of cellulose is indirectly achieved by influencing such hydrogen bond interactions. The strong preferential solvation of CH3COO− by the protic solvents (CH3OH and H2O) can compete with the cellulose–CH3COO− interaction in the dissolution process, resulting in decreased cellulose solubility. On the other hand, the aprotic solvents (DMSO and DMF) can partially break down the ionic association of C4mimCH3COO by solvation of the cation and anion, but no preferential solvation was observed. The dissociated CH3COO− would readily interact with cellulose to improve the dissolution of cellulose. Furthermore, the effect of the aprotic solvent-to-IL molar ratio on the dissolution of cellulose in C4mimCH3COO/DMSO systems was investigated, and a possible mechanism is proposed. These simulation results provide insight into how a cosolvent affects the dissolution of cellulose in ILs and may motivate further experimental studies in related fields.
Early diagnosis and monitoring of SARS-CoV-2 virus is essential to control COVID-19 outbreak. In this study, we propose a promising surface enhanced Raman scattering (SERS)-based COVID-19 biosensor ...for ultrasensitive detection of SARS-CoV-2 virus in untreated saliva. The SERS-immune substrate was fabricated by a novel oil/water/oil (O/W/O) three-phase liquid-liquid interfaces self-assembly method, forming two layers of dense and uniform gold nanoparticle films to ensure the reproducibility and sensitivity of SERS immunoassay. The detection was performed by an immunoreaction between the SARS-CoV-2 spike antibody modified SERS-immune substrate, spike antigen protein and Raman reporter-labeled immuno-Ag nanoparticles. This SERS-based biosensor was able to detect the SARS-CoV-2 spike protein at concentrations of 0.77 fg mL−1 in phosphate-buffered saline and 6.07 fg mL−1 in untreated saliva. The designed SERS-based biosensor exhibited excellent specificity and sensitivity for SARS-CoV-2 virus without any sample pretreatment, providing a potential choice for the early diagnosis of COVID-19.
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•A new SERS-based COVID-19 biosensor was developed for ultrasensitive detection of SARS-CoV-2 virus.•A novel three-phase interfaces self-assembly method was applied for fabricating the SERS-immune substrate.•The SERS-immune substrate assembled by highly dense and uniform Au NPs can improve the reproductivity of SERS immunoassay.•The biosensor can detect the SARS-CoV-2 spike protein at ultra-low concentration of 6.07 fg mL−1 in untreated saliva.•The biosensor exhibits excellent specificity and sensitivity for SARS-CoV-2 virus without any sample pretreatment.
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