Latest ArticlesWe 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.
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.
Inspired by the indolopyridoquinazoline scaffold of natural products evodiamine and rutaecarpine, novel triple G4 and Top1/2 ligands were rationally designed and synthesized. Systematic structure–activity relationship (SAR) studies led to the discovery of compound 15g, which effectively induced and stabilized G4 and inhibited Top1/2 with potent antitumor activity. Compound 15g represents a valuable chemical tool or lead compound for antitumor drug discovery. This proof-of-concept study also validated the feasibility of using planar natural products scaffold as templates to design new G4 ligands.
Luminescent spin crossover (SCO) materials have attracted significant interest owing to their potential applications in magneto-optical switches. However, the majority of previously reported FeⅡ-based SCO complexes are adversely affected by fluorescence quenching in the solid-state. Here, we have constructed the first mononuclear FeⅡ complex decorated with an aggregation-induced emission (AIE) luminophore (i.e., tetraphenylethylene) that exhibits synergistic SCO and fluorescence behavior. Intriguingly, we obtained two types of crystals in different solvent systems, both displaying distinct magnetic bistability and fluorescence properties. The fluorescence intensity was observed to track the magnetic susceptibility, which confirmed that SCO and solid-state fluorescence operate synergistically. We introduce a novel approach for the construction of luminescent SCO compounds using an AIEgen as a luminophore, which leads to fluorescence emission in the solid-state, thus allowing us to study the synergy between SCO and fluorescence.
The distinct influences of cephalosporins (CEPs, i.e., cefamandole nafate and cefpirome sulfate) affiliated to different generations on the volatile fatty acids (VFAs) production and antibiotic resistance genes (ARGs) fates during waste activated sludge (WAS) fermentation were unveiled. The presence of CEPs mainly exhibited negative effects on the total VFAs production (5%–15% reduction), especially the cefamandole nafate, which is quite different to previous understanding. Further investigation revealed that the CEPs contributed to the solubilization and hydrolysis but inhibited the acidification process by affecting the functional microbial populations (i.e., Tissierella) and general microbial metabolic activities (i.e., pyruvate metabolism and VFAs biosynthesis). In addition, CEPs (especially the cefpirome sulfate) caused the propagation of ARGs (i.e., blaTEM, tetX and mexF) during WAS fermentation. CEPs enhanced the cell membrane permeability to promote the antibiotics mechanism of efflux pump and the horizontal transfer of ARGs. Also, the CEPs altered the regulatory systems (i.e., two component system) and microbial populations associated with ARGs, resulting in the proliferation of specific ARGs. Overall, the dissimilarity of different CEPs impacts on the WAS fermentation for VFAs production and ARGs variations enlightened the diverse environmental behaviors of anthropogenic pollutants and evoked the caution of ecological risks.
A novel Au11Cd nanocluster was synthesized by developing a combined method and controlling the kinetics, and another Au26Cd5 nanocluster was also obtained after the conditions were changed in the same reaction, which could transfer to Au11Cd in a two-way style. Both alloy nanoclusters can photocatalyze the production of singlet oxygen (1O2) and exhibit enhanced efficiencies in photocatalyzing two kinds of organic oxidations involving singlet oxygen compared with their non-alloyed mother nanoclusters, indicating that the Cd-doping might be an efficient way to enhance the photocatalysis performance of gold nanoclusters and metal nanoclusters are promising photocatalysts for organic oxidation involving singlet oxygen.
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.
Graphite carbon nitride (g-C3N4) is a promising non-metal photocatalyst for photocatalytic hydrogen production, but its performance is still limited due to sluggish charges separation and low utilization of light. In this work, P-doped and N-doped carbon dots (NCDs) supported g-C3N4 were successfully prepared via hydrothermal and polymerization reactions. The sub-bandgap formed by P-doping enhances the utilization of visible light, and the high electron density of P sites is conducive to the trapping of holes. NCDs also improve light utilization and, more importantly, act as electron acceptors and transporters to promote electron transport. The built-in electric field formed by the synergy of P-doping and NCDs-loading greatly promotes the separation of charges. The PCN/NCDs showed a significantly improved hydrogen evolution activity of 3731 µmol h−1 g−1, which was 6.7 times that of pure carbon nitride (560 µmol h−1 g−1). This strategy may be generalized to the design of g-C3N4 -based photocatalysts, facilitating the separation of charges for enhanced catalytic activity.
As a glucagon (GCG) receptor (GCGR) and glucagon-like peptide 1 (GLP-1) receptor (GLP-1R) dual agonist, oxyntomodulin (OXM) has been attracting scientific attentions due to its efficacies of suppressing appetite, increasing energy expenditure, and inducing body weight loss in obese humans. Based on the scaffold of native OXM, specific helix-favoring amino acids substitutions and the consequent salt bridge formations were believed to offer enhanced and balanced GCGR/GLP-1R activations through increasing α-helical conformation. Novel OXM analogues are obtained by intramolecular lactam stapling of positions [Glu16 & Lys20] or [Lys17 & Glu21] to further strengthen conformationally constrained stabilization. Even though the lactam staple does not provide additional dual GCGR/GLP-1R activations in vitro, the stapled OXM analogues are firstly reported to have higher or lower anti-PANC-1 cell proliferation activity, meanwhile which has no obvious inhibitory effect on the proliferation of HeLa cells. Therefore, it is speculated that the stapled analogues may have the potential to inhibit the proliferation of specific cancer cell types. Among the stapled peptides as well as their precursors, analogue 6 has the most prominent anti-PANC-1 proliferation activity with the IC50 value of 115.1 µmol/L. Its mechanism of actions including effective signal pathways should be worth further investigations in future.