Abstract
Engineering catalytic sites at the atomic level provides an opportunity to understand the catalyst’s active sites, which is vital to the development of improved catalysts. Here we show a ...reliable and tunable polyoxometalate template-based synthetic strategy to atomically engineer metal doping sites onto metallic 1T-MoS
2
, using Anderson-type polyoxometalates as precursors. Benefiting from engineering nickel and oxygen atoms, the optimized electrocatalyst shows great enhancement in the hydrogen evolution reaction with a positive onset potential of ~ 0 V and a low overpotential of −46 mV in alkaline electrolyte, comparable to platinum-based catalysts. First-principles calculations reveal co-doping nickel and oxygen into 1T-MoS
2
assists the process of water dissociation and hydrogen generation from their intermediate states. This research will expand on the ability to improve the activities of various catalysts by precisely engineering atomic activation sites to achieve significant electronic modulations and improve atomic utilization efficiencies.
Two-dimensional Ruddlesden–Popper phase (2DRP) perovskites are known to exhibit improved photostability and environmental stability compared with their three-dimensional (3D) counterparts. However, ...fundamental questions remain over the interaction between the bulky alkylammoniums and the 2DRP perovskite framework. Here, we unambiguously demonstrate that a sulfur–sulfur interaction is present for a new bulky alkylammonium, 2-(methylthio)ethylamine hydrochloride (MTEACl). In addition to a weaker van der Waals interaction, the interaction between sulfur atoms in two MTEA molecules enables a (MTEA)2(MA)4Pb5I16 (n = 5) perovskite framework with enhanced charge transport and stabilization. The result is 2DRP perovskite solar cells with significantly improved efficiency and stability. Cells with a power conversion efficiency as high as 18.06% (17.8% certified) are achieved, along with moisture tolerance for up to 1,512 h (under 70% humidity conditions), thermal stability for 375 h (at 85 °C) and stability under continuous light stress (85% of the initial efficiency retained over 1,000 h of operation at the maximum power point).Two-dimensional perovskite solar cells have been engineered to be robust against moisture, high temperatures and light stress.
Chemistry under high pressure Miao, Maosheng; Sun, Yuanhui; Zurek, Eva ...
Nature reviews. Chemistry,
10/2020, Letnik:
4, Številka:
10
Journal Article
Recenzirano
Thanks to the development of experimental high-pressure techniques and methods for crystal-structure prediction based on quantum mechanics, in the past decade, numerous new compounds, mostly binary, ...with atypical compositions have been predicted, and some have been synthesized. Differing from conventional solid-state materials, many of these new compounds are comprised of various homonuclear chemical species, such as dimers, trimers, pentagonal and heptagonal rings, polymeric chains, atomic layers and 3D networks. Strikingly, it has been shown that pressure can alter the chemistry of an element by activating its (semi)core electrons, unoccupied orbitals and even the non-atom-centred quantum orbitals located on the interstitial sites, leading to many new surprising phenomena. This Review provides a summary of atypical compounds that result from the effects of high pressure on either the chemical bonds or the local orbitals. We describe various unusual chemical species and motifs, show how the chemical properties of the elements are altered under pressure and illustrate how compound formation is favoured even in situations in which chemical bonds are not formed. An extraordinary new picture of chemistry emerges as we piece together these unexpected high-pressure phenomena. In marked contrast to the previously held beliefs regarding the behaviour of solids under pressure, we are learning that the quantum-mechanical features of electrons, such as those that lead to the formation of directional bonds, inhomogeneous distributions of electrons and atoms, as well as variations in symmetry, might be magnified under pressure. We discuss the influence of these phenomena on future studies that will probe chemistry at higher pressures and explore more complex chemical compositions than those that have been studied to date.High pressure leads to striking new chemistry. Many new compounds with atypical compositions and a plethora of novel chemical species can be stabilized by the formation of homonuclear bonds and the activation of core electrons, non-valence and non-atomic orbitals.
MicroRNA exhibits differential expression levels in cancer and can affect cellular transformation, carcinogenesis and metastasis. Although fluorescence techniques using dye molecule labels have been ...studied, label-free molecular-level quantification of miRNA is extremely challenging. We developed a surface plasmon resonance sensor based on two-dimensional nanomaterial of antimonene for the specific label-free detection of clinically relevant biomarkers such as miRNA-21 and miRNA-155. First-principles energetic calculations reveal that antimonene has substantially stronger interaction with ssDNA than the graphene that has been previously used in DNA molecule sensing, due to thanking for more delocalized 5s/5p orbitals in antimonene. The detection limit can reach 10 aM, which is 2.3-10,000 times higher than those of existing miRNA sensors. The combination of not-attempted-before exotic sensing material and SPR architecture represents an approach to unlocking the ultrasensitive detection of miRNA and DNA and provides a promising avenue for the early diagnosis, staging, and monitoring of cancer.
Elaborate design of highly active and stable catalysts from Earth-abundant elements has great potential to produce materials that can replace the noble-metal-based catalysts commonly used in a range ...of useful (electro)chemical processes. Here we report, for the first time, a synthetic method that leads to in situ growth of {2̅10} high-index faceted Ni3S2 nanosheet arrays on nickel foam (NF). We show that the resulting material, denoted Ni3S2/NF, can serve as a highly active, binder-free, bifunctional electrocatalyst for both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). Ni3S2/NF is found to give ∼100% Faradaic yield toward both HER and OER and to show remarkable catalytic stability (for >200 h). Experimental results and theoretical calculations indicate that Ni3S2/NF’s excellent catalytic activity is mainly due to the synergistic catalytic effects produced in it by its nanosheet arrays and exposed {2̅10} high-index facets.
Flexible thin films of poly(nickel‐ethylenetetrathiolate) prepared by an electrochemical method display promising n‐type thermoelectric properties with the highest ZT value up to 0.3 at room ...temperature. Coexistence of high electrical conductivity and high Seebeck coefficient in this coordination polymer is attributed to its degenerate narrow‐bandgap semiconductor behavior.
It is significant for the healthy outcome of patients with psoriasis (PSO) to improve their self-management efficacy. A standardized assessment tool, however, was lacking. Therefore, we aimed to ...develop a self-management efficacy questionnaire for patients with PSO (SMEQ-PSO) and evaluate its psychometric properties.
A cross-sectional study developing clinical evaluation tool was conducted from October 2021 to August 2022. In the process of developing SMEQ-PSO, three phases were involved: item generation, item evaluation, and psychometric evaluation.
The SMEQ-PSO with five dimensions and 28 items was developed. The questionnaire's content validity index was 0.976. Exploratory factor analysis indicated a five-factor structure (self-efficacy of psychosocial adaptation, self-efficacy of daily life management, self-efficacy of skin management, self-efficacy of disease knowledge management and self-efficacy of disease treatment management) that explained 62.039% of the total variance. Confirmatory factor analysis indicated appropriate fit of the five-factor model. The overall Cronbach'α coefficient was 0.930, the test-retest reliability was 0.768 and the split half reliability coefficients was 0.952.
The 28-item SMEQ-PSO is a reliable and valid tool that can be used to assess the self-management efficacy among patients with PSO and provide personalized interventions based on their individual circumstances to improve their health outcomes.
Phosphorescent near‐infrared (NIR) organic light‐emitting devices (OLEDs) have drawn increasing attention for their promising applications in the fields such as photodynamic therapy and night‐vision ...readable displays. Here, three simple phosphorescent Pt(II) complexes are synthesized, and their intermolecular interactions are investigated in crystals and neat films by X‐ray single crystal diffraction and grazing‐incidence wide‐angle X‐ray scattering, respectively. The photophysical properties, molecular aggregation (including Pt–Pt interaction), molecular packing orientation, and electron transport ability are all influenced by the strong intermolecular hydrogen bonds. Consequently, the nondoped OLEDs based on tBu‐Pt and F‐Pt show electroluminescent emissions in NIR region with the highest external quantum efficiencies of 13.9% and 16.7%, respectively.
Because of enhanced molecular aggregations induced by strong intermolecular hydrogen bonds, a simple Pt(II) complex neat film shows near‐infrared (NIR) emission with high photoluminescence quantum yield, improved electron transport ability, and preferred molecular orientation. The related nondoped organic light‐emitting device (OLED) exhibits the near‐infrared (NIR) emission with a peak external quantum efficiency of 16.7%.
Moiré superlattices (MSLs) are modulated structures produced from homogeneous or heterogeneous 2D layers stacked with a twist angle and/or lattice mismatch. Expanding the range of available ...materials, methods for fabricating MSL, and realization of unique emergent properties are key challenges. Here we report a facile bottom-up synthesis of homogeneous MSL based on a wide-gap 2D semiconductor, BiOCl, using a one-pot solvothermal approach with robust reproducibility. Unlike previous MSLs usually prepared by directly stacking two monolayers, our BiOCl MSLs are realized in a scalable, direct way through chemical growth of spiral-type nanosheets driven by screw-dislocations. We find emergent properties including large band gap reduction (∼0.6 eV), two-fold increase in carrier lifetime, and strongly enhanced photocatalytic activity. First-principles calculations reveal that such unusual properties can be ascribed to the locally enhanced inter-layer coupling associated with the Moiré potential modulation. Our results demonstrate the promise of MSL materials for chemical and physical functions.
A series of thiophene-diketopyrrolopyrrole-based quinoidal small molecules (TDPPQ-2–TDPPQ-5) bearing branched alkyl chains with different side-chain lengths and varied branching positions are ...synthesized. Field-effect transistor (FET) measurement combined with thin-film characterization is utilized to systematically probe the influence of the side-chain length and branching position on the film microstructure, molecular packing, and, hence, charge-transport property. All of these TDPPQ derivatives show air-stable n-channel transporting behavior in spin-coated FET devices, which exhibit no significant decrease in mobility even after being stored in air for 2 months. Most notably, TDPPQ-3 exhibits an outstanding n-channel semiconducting property with electron mobilities up to 0.72 cm2 V–1 s–1, which is an unprecedented value for spin-coated DPP-based n-type semiconducting small molecules. A balance of high crystallinity, satisfactory thickness uniformity and continuity, and strong intermolecular interaction accounts for the superior charge-transport characteristics of TDPPQ-3 films. Our study demonstrates that tuning the length and branching position of alkyl side chains of semiconducting molecules is a powerful strategy for achieving high FET performance.
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