Latest ArticlesCovalent organic frameworks (COFs) are a class of crystalline porous organic materials with variable structures and fascinating properties. The intrinsic low conductivity impedes their widely application in optoelectronic. Iodine doping is an effective way to enhance the electrical conductivity of COFs. Here, a novel 3D imine COF with lvt topology is synthesized from two different pentacene derivatives with the same core in the form of structural complementarity. DDHP-COF is a highly crystalline material featuring high surface area of 1679 m2/g and excellent thermal stability up to 490 ℃. Upon doping with iodine, the electrical conductivity can reach as high as 1.5 × 10−2 S/m which is significantly enhanced over 6 orders of magnitude compared with the pristine COF.
Aqueous zinc-ion batteries (ZIBs) have attracted significant attentions because of low cost and high reliability. However, conventional ZIBs are severely limited by the development of high energy density cathode materials with reversible Zn2+ insertion/extraction. Herein, a conducting polymer intercalated MoO3 (PMO) with extensively extended interlayer spacing is developed as a high-performance ZIBs cathode material. The interlayer spacing of PMO is prominently increased which results in an improved Zn2+ mobility during charge and discharge process. More significantly, the electrochemical results reveals that the intercalation of PANI facilitates the charge storage and reinforces the layered structure of MoO3, leading to a high capacity and good cycling stability. DFT calculation further reveals the intercalation of PANI into MoO3 significantly lower Zn2+ diffusion barrier. Benefit from these advantages, the ZIBs based on PMO electrode delivers a considerable capacity of 157 mAh/g at 0.5 A/g and ameliorative stability with 63.4% capacity retention after 1000 cycles.
We use a single-molecule self-assembled layer of an aromatic organophosphonic acid (2PACz) to modify the cathode interface layer in inverted organic solar cells (OSCs). The modified OSCs not only have an obvious improvement in power conversion efficiency (PCE), but also demonstrate greatly enhanced air stability. Ultraviolet photoelectron spectroscopy shows that the work function of cathode interlayer after modification by 2PACz is more suitable for electron extraction. In addition, the surface energy is reduced without affecting the film deposition, which will be beneficial to reduce the interfacial traps. As a result, the PCE of OSCs based on the PBDB-T: IT-M system is increased, and its stability in air is greatly improved (remaining 88% of its initial PCE after 555 h in air). Therefore, we provide a new strategy for constructing high-performance non-fullerene OSCs with enhanced air stability.
Based on the coumarin skeleton, we deliberately designed two groups of fluorophores, termed as Coum-R and Naph-Coum-R, using the diphenylamino group as the electron donor, which displayed long-wavelength emissions (red spectral region), large Stokes shift (up to 204 nm), superior AIE performance, and large two-photon absorbance cross-sections (as high as 365 GM). The electron-withdrawing substituents at the 3-position of these dyes could induce a significant red-shift in their emission spectra. Preliminary imaging experiments demonstrated the capability of these dyes as two-photon fluorophores for specifically staining lipid droplets in living cells.
Developing highly efficient photocatalysts for selective oxidation of benzene to phenol is of great significance. However, it is still challenging to simultaneously achieve high conversion rate and selectivity. Herein, we demonstrate 99.9% of benzene photoconversion and 99.1% of phenol selectivity under the illumination of AM 1.5 for 12 h. For this purpose, an advanced CuO@CN photocatalyst has been fabricated by loading tubular carbon nitride (CN) with CuO nanoparticles thermally polymerized from Cu-based metal-organic frameworks (MOFs). The sluggish photocharge carrier recombination rate and the excellent stability indicate that the as-prepared nanocomposite is an ideal photocatalyst for benzene oxidation application. This work paves a new avenue for designing novel photocatalyst based on MOFs and carbon nitride materials.
Controlling the particle size of catalyst to understand the active sites is the key to design efficient electrocatalysts toward hydrogen electrode reactions including hydrogen oxidation and evolution (HOR/HER). Herein, the hydrogen and hydroxyl adsorption on Ru/C could be effectively tuned for HOR/HER by simple controlling the particle sizes. It is found that the metallic Ru (Ru0) is the active site for HOR/HER, while oxidized Ru (Rux+) will hinder the adsorption and desorption of hydrogen on the catalyst. For the HOR, catalyst with small particles is more efficient, due to it is a three-phase interface reaction of gas on the surface of the catalyst. For the HER, the metallic state of Ru is crucial. The deconvolution of hydrogen peaks indicates that the catalytic sites with low hydrogen binding energy (HBE) shoulder the majority of the HOR activity. CO stripping curve further demonstrates that the stronger hydroxyl species (OHad) affinity is beneficial to promote the HOR performance. The results indicate that the design of efficient HOR/HER catalyst should focus on the balance between particle size and metallic states.
The coevolution and coexistence of bacterial–fungal consortium have been widely reported in various natural ecosystems. The transboundary communication mediated by bacterial acyl–homoserine lactone signals probably is the driving force of fungal spore germination. This study aimed to report a functional bacterial signal molecule, C10-acyl homoserine lactone, which could be sensed by Galactomyces geotrichum. The spore germination rates of G. geotrichum increased by 22%. Meanwhile, carbohydrate production improved by 1.0- to 2.5-fold. G. geotrichum signaled to C10-HSL through receptor gene Rho1 and made a response in cell wall assembly and carbohydrate biosynthesis by the upregulated expression (above 1-fold) of functional genes, such as Smi1, Utr2, and Chs2. It contributed to spore germination and morphology transformation together. This study provides a novel perspective for understating the transboundary cooperation between fungi and bacteria by cell-to-cell communication.
Erythrocyte membrane (EM)-camouflaged chemotherapeutic delivery nanovehicles hold promise for solid tumor therapy because of their excellent biostability and biocompatibility. However, it is accompanied with insufficient targeting effect and deficient pharmacokinetic behavior due to the lack of a regulated biointerface to navigate and overcome biological transportation obstacles in solid tumor therapy. Herein, an anti-epidermal growth factor receptor (EGFR) aptamer (EApt) modified and EM-cloaked chemotherapeutic nanomissile delivery system was constructed. The anchored-EApt acting as a specific EGFR suppressor promotes to inhibit the overexpression of EGFR and initiate the cell apoptosis. Importantly, the resulting PLGA-DOX@EM-EApt orchestrated the bioactivity of each component and provided synergistic cell apoptosis and antitumor effects by precisely suppressing EGFR expression levels and delivering DOX. The in vitro and in vivo experimental results confirmed that the immune escape and active targeting behaviors of PLGA-DOX@EM-EApt could significantly promote its drug retention and tumor inhibition abilities. Our findings propose a novel strategy using the biointerface functionalization technique, demonstrating a promising therapeutic platform via a biomimetic drug delivery system for precise solid tumor recognition and synergistic therapy.
Chiral glycosyl lactone is an important class of bioactive compound and pharmaceutical intermediate in nature, especially for chiral lactones with 4 carbon atoms, which are very useful building blocks for synthesis of biologically interesting compounds. Herein, a selective dehydrogenation and solvent matched catalytic system under oxygen-free conditions was developed to try to achieve the one-step direct conversion of cyclic hemiacetal sugars toward their chiral glycosyl lactones. During the process, the inherent structural characteristics of sugar was efficiently utilized, and the transfer of its chiral centers was realized. Under the optimum condition, the corresponding lactones were successfully prepared from C4-C6 sugars with cyclic hemiacetal structure in acetonitrile. The reaction mechanism in acetonitrile was explored by the first principle density functional theory calculations and tracking reaction process. It was found that the high lactone yield in acetonitrile was due to the high proportion of α-conformation form among multiple tautomers in it. This selective dehydrogenation process may further extend the possibility of the preparation of chiral synthons from carbohydrates directly.
The elaborate regulation of heterostructure interface to accelerate the interfacial charge separation is one of practicable approaches to improve the photocatalytic CO2 reduction performance of halide perovskite (HP) materials. Herein, we report an in-situ growth strategy for the construction of 2D CsPbBr3 based heterostructure with perovskite oxide (SrTiO3) nanosheet as substrate (CsPbBr3/SrTiO3). Lattice matching and matchable energy band structures between CsPbBr3 and SrTiO3 endow CsPbBr3/SrTiO3 heterostructure with an efficient interfacial charge separation. Moreover, the interfacial charge transfer rate can be further accelerated by etching SrTiO3 with NH4F to form flat surface capped with Ti−O bonds. The resultant 2D/2D T-SrTiO3/CsPbBr3 heterostructure exhibits an impressive photocatalytic activity for CO2 conversion with a CO yield of 120.2 ± 4.9 µmol g−1 h−1 at the light intensity of 100 mW/cm2 and water as electron source, which is about 10 and 7 times higher than those of the pristine SrTiO3 and CsPbBr3 nanosheets, surpassing the reported halide perovskite-based photocatalysts under the same conditions.