21 research outputs found

    Mapping the Space of Inorganic and Hybrid Halides and Their Optical Properties Using Mechanochemistry and First-Principles Calculations

    No full text
    Inorganic and hybrid metal halides (MHs) are a class of ionic compounds that attract growing interest due to their richness of structure, properties, and resulting applications. These are largely ionic in nature and hence dominantly follow solid-state synthesis reactions rather than the solution approach. Keeping the importance of these materials in mind, herein, combination reactions of compounds via mechanochemistry is considered as a universal synthetic approach for the synthesis of MHs, and a library of MHs, including all inorganic MHs, ternary (A–B–X) MHs, enormous number of quaternary MHs based on representative 10 double perovskites (A–B–B′–X), and most of the hybrid ones based on randomly selected 49 samples as representative from the 1300 ones, are reported. The fundamental structure–property relationships are well revealed, where most of the MHs exhibit bright photoluminescence and/or magnetic properties for a few materials. Hence, the adopted concept of material design and related with their crystal structure and material properties for such a large number of halide materials not only help in building a library but also provide fundamental guidance to develop new MH materials with selective optoelectronic and magnetic properties.

    Tunable Schottky Barrier and Efficient Ohmic Contacts in MSi<sub>2</sub>N<sub>4</sub> (M = Mo, W)/2D Metal Contacts

    No full text
    Monolayer MSi2N4 (M = Mo, W) has been fabricated and proposed as a promising channel material for field-effect transistors (FETs) due to the high electron/hole mobility. However, the barrier between the metal electrode and MSi2N4 will affect device performance. Hence, it is desirable to reduce the barrier for achieving high-performance electrical devices. Here, using density functional theory (DFT) calculations, we systematically investigate the electrical properties of the van der Waals (vdW) contacts formed between MSi2N4 and two-dimensional (2D) metals (XY2, X = Nb, Ta, Y = S, Se, Te). It is found that the contact types and Schottky barrier height (SBH) of MSi2N4/XY2 can be effectively tuned by selecting 2D metals with different work functions (WFs). Specifically, n- and p-type Schottky contacts and Ohmic contacts can be achieved in MSi2N4/XY2. Among them, MoSi2N4/H-NbS2, WSi2N4/H-XS2, and WSi2N4/H-NbSe2 present Ohmic contacts due to the high WF of 2D metals. Notably, the pinning factors of MSi2N4/XY2 are obviously larger than those of the other 2D semiconductor/metal contacts, indicating that the Fermi-level pinning (FLP) effect is weak in MSi2N4/XY2. Therefore, vdW stack engineering can strongly weaken the FLP effect, making the Schottky barrier tunable in MSi2N4/XY2 by choosing 2D metals with different WFs. The results provide important insights into the selection of appropriate electrodes and valuable guidance for the development of MSi2N4-based 2D electronic devices with high performance

    Table_1_LncmiRHG-MIR100HG: A new budding star in cancer.docx

    No full text
    MIR100HG, also known as lncRNA mir-100-let-7a-2-mir-125b-1 cluster host gene, is a new and critical regulator in cancers in recent years. MIR100HG is dysregulated in various cancers and plays an oncogenic or tumor-suppressive role, which participates in many tumor cell biology processes and cancer-related pathways. The errant expression of MIR100HG has inspired people to investigate the function of MIR100HG and its diagnostic and therapeutic potential in cancers. Many studies have indicated that dysregulated expression of MIR100HG is markedly correlated with poor prognosis and clinicopathological features. In this review, we will highlight the characteristics and introduce the role of MIR100HG in different cancers, and summarize the molecular mechanism, pathways, chemoresistance, and current research progress of MIR100HG in cancers. Furthermore, some open questions in this rapidly advancing field are proposed. These updates clarify our understanding of MIR100HG in cancers, which may pave the way for the application of MIR100HG-targeting approaches in future cancer diagnosis, prognosis, and therapy.</p

    Data_Sheet_1_Enzymes and microorganisms jointly promote the fermentation of rapeseed cake.docx

    No full text
    Rapeseed cake is a by-product of rapeseed oil separation. The nutritional components of rapeseed cake mainly include a variety of carbohydrates, proteins, and minerals. In order to improve the conversion rate of rapeseed cake, we studied the physicochemical properties, the structure of microbial communities, and the composition of metabolites in rapeseed cake after enzymatic fermentation. The results showed that the addition of enzymatic preparation increased microbial diversity. The relative abundance of Bacillus, Lysinibacillus, Empedobacter, Debaryomyces, Hyphopichia, and Komagataella in enzymatic fermentation was significantly higher than that in natural fermentation. Unlike natural fermentation, microbial diversity during enzymatic fermentation is specific, which improves the efficiency of fermentation. Otherwise, enzymatic fermentation promotes the conversion of macromolecular substances in rapeseed cake, which increases small metabolites, such as fatty acids, organic acids, amino acids and their derivatives. The metabolite enrichment pathway is mostly concentrated in sugar metabolism and fatty acid metabolism. In conclusion, after adding enzymatic preparation, enzymes and microorganisms jointly promote the transformation of macromolecules during the fermentation of rapeseed cake, which laid a good foundation for further utilization of rapeseed cake.</p

    Vapor Growth and Tunable Lasing of Band Gap Engineered Cesium Lead Halide Perovskite Micro/Nanorods with Triangular Cross Section

    No full text
    Although great efforts have been devoted to the synthesis of halide perovskites nanostructures, vapor growth of high-quality one-dimensional cesium lead halide nanostructures for tunable nanoscale lasers is still a challenge. Here, we report the growth of high-quality all-inorganic cesium lead halide alloy perovskite micro/nanorods with complete composition tuning by vapor-phase deposition. The as-grown micro/nanorods are single-crystalline with a triangular cross section and show strong photoluminescence which can be tuned from 415 to 673 nm by varying the halide composition. Furthermore, these single-crystalline perovskite micro/nanorods themselves function as effective Fabry–Perot cavities for nanoscale lasers. We have realized room-temperature tunable lasing of cesium lead halide perovskite with low lasing thresholds (∼14.1 μJ cm<sup>–2</sup>) and high <i>Q</i> factors (∼3500)

    Spring-Like Pseudoelectroelasticity of Monocrystalline Cu<sub>2</sub>S Nanowire

    No full text
    Prediction from the dual-phase nature of superionic conductorsboth solid and liquid-likeis that mobile ions in the material may experience reversible extraction–reinsertion by an external electric field. However, this type of pseudoelectroelasticity has not been confirmed <i>in situ</i>, and no details on the microscopic mechanism are known. Here, we <i>in situ</i> monitor the pseudoelectroelasticity of monocrystalline Cu<sub>2</sub>S nanowires (NWs) using transmission electron microscopy (TEM). Specifically, we reveal the atomic scale details including phase transformation, migration and redox reactions of Cu<sup>+</sup> ions, nucleation, growth, as well as spontaneous shrinking of Cu protrusion. Caterpillar-diffusion-dominated deformation is confirmed by the high-resolution transmission electron microscopy (HRTEM) observation and <i>ab initio</i> calculation, which can be driven by either an external electric field or chemical potential difference. The observed spring-like behavior was creatively adopted for electric nanoactuators. Our findings are crucial to elucidate the mechanism of pseudoelectroelasticity and could potentially stimulate in-depth research into electrochemical and nanoelectromechanical systems

    New Insights into Electrochemical Lithiation/Delithiation Mechanism of α‑MoO<sub>3</sub> Nanobelt by in Situ Transmission Electron Microscopy

    No full text
    The α-MoO<sub>3</sub> nanobelt has great potential for application as anode of lithium ion batteries (LIBs) because of its high capacity and unique one-dimensional layer structure. However, its fundmental electrochemical failure mechanism during first lithiation/delithiation process is still unclear. Here, we constructed an electrochemical setup within α-MoO<sub>3</sub> nanobelt anode inside a transmission electron microscope to observe in situ the mircostructure evolution during cycles. Upon first lithiation, the α-MoO<sub>3</sub> nanobelt converted into numerous Mo nanograins within the Li<sub>2</sub>O matrix, with an obvious size expansion. Interestingly, α-MoO<sub>3</sub> nanobelt was found to undergo a two-stage delithiation process. Mo nanograins were first transformed into crystalline Li<sub>1.66</sub>Mo<sub>0.66</sub>O<sub>2</sub> along with the disappearance of Li<sub>2</sub>O and size shrink, followed by the conversion to amorphous Li<sub>2</sub>MoO<sub>3</sub>. This irreversible phase conversion should be responsible for the large capacity loss in first cycle. In addition, a fully reversile phase conversion between crystalline Mo and amorphous Li<sub>2</sub>MoO<sub>3</sub> was revealed accompanying the formation and disapperance of the Li<sub>2</sub>O layer during the subsequent cycles. Our experiments provide direct evidence to deeply understand the distinctive electrochemical lithiation/delithiation behaviors of α-MoO<sub>3</sub> nanobelt, shedding light onto the development of α-MoO<sub>3</sub> anode for LIBs

    Solubility of Boron, Carbon, and Nitrogen in Transition Metals: Getting Insight into Trends from First-Principles Calculations

    No full text
    Efficient chemical vapor deposition synthesis of two-dimensional (2D) materials such as graphene, boron nitride, and mixed BCN systems with tunable band gaps requires precise knowledge of the solubility and mobility of B/C/N atoms in the transition metals (TMs) used as substrates for the growth. Yet, surprisingly little is known about these quantities either from experiments or simulations. Using first-principles calculations, we systematically study the behavior of B/C/N impurity atoms in a wide range of TMs. We compute formation energies of B/C/N interstitials and demonstrate that they exhibit a peculiar but common behavior for TMs in different rows of the periodic table, as experimentally observed for C. Our simulations indicate that this behavior originates from an interplay between the unit cell volume and filling of the d-shell electronic states of the metals. We further assess the vibrational and electronic entropic contributions to the solubility, as well as the role of anharmonic effects. Finally, we calculate the migration barriers, an important parameter in the growth kinetics. Our results not only unravel the fundamental behavior of interstitials in TMs but also provide a large body of reference data, which can be used for optimizing the growth of 2D BCN materials

    Zn–Cu–In–Se Quantum Dot Solar Cells with a Certified Power Conversion Efficiency of 11.6%

    No full text
    The enhancement of power conversion efficiency (PCE) and the development of toxic Cd-, Pb-free quantum dots (QDs) are critical for the prosperity of QD-based solar cells. It is known that the properties (such as light harvesting range, band gap alignment, density of trap state defects, etc.) of QD light harvesters play a crucial effect on the photovoltaic performance of QD based solar cells. Herein, high quality ∼4 nm Cd-, Pb-free Zn–Cu–In–Se alloyed QDs with an absorption onset extending to ∼1000 nm were developed as effective light harvesters to construct quantum dot sensitized solar cells (QDSCs). Due to the small particle size, the developed QD sensitizer can be efficiently immobilized on TiO<sub>2</sub> film electrode in less than 0.5 h. An average PCE of 11.66% and a certified PCE of 11.61% have been demonstrated in the QDSCs based on these Zn–Cu–In–Se QDs. The remarkably improved photovoltaic performance for Zn–Cu–In–Se QDSCs vs Cu–In–Se QDSCs (11.66% vs 9.54% in PCE) is mainly derived from the higher conduction band edge, which favors the photogenerated electron extraction and results in higher photocurrent, and the alloyed structure of Zn–Cu–In–Se QD light harvester, which benefits the suppression of charge recombination at photoanode/electrolyte interfaces and thus improves the photovoltage
    corecore