Latest ArticlesThe power conversion efficiencies (PCEs) of organic solar cells (OSCs) have reached 18% recently, which have already met the demand of practical application. However, these outstanding results were generally achieved with donor-acceptor (D-A) type copolymer donors, which can hardly fulfill the low-cost large-scale production due to their complicated synthesis processes. Therefore, developing polymer donors with simple chemical structures is urgent for realizing low-cost OSCs. Polythiophene (PT) derivatives are currently regarded as promising candidates for such kind of donor materials, which has been illustrated in many works. In this work, two new alkylthio substituted PT derivatives, P301 and P302, were synthesized and tested as donors in the OSCs using Y5 as the acceptor. In comparison, the introduction of fluorine atoms on the backbone of P302 can not only downshift the energy levels, but also greatly improve the phase separation morphologies of the active layers, which is ascribed to the enhanced aggregation effect and the reduced miscibility with the non-fullerene acceptor. As a result, the P302:Y5-based OSC exhibits a significantly improved PCE of 9.65% than that of P301:Y5-based one, indicating the important role of fluorination in the construction of efficient PT derivative donors.
Hematite (α-Fe2O3) is a promising photoanode for photoelectrochemical (PEC) water splitting. However, the severe charge recombination and sluggish water oxidation kinetics extremely limit its use in photohydrogen conversion. Herein, a co-activation strategy is proposed, namely through phosphorus (P) doping and the loading of CoAl-layered double hydroxides (CoAl-LDHs) cocatalysts. Unexpectedly, the integrated system, CoAl-LDHs/P-Fe2O3 photoanode, exhibits an outstanding photocurrent density of 1.56 mA/cm2 at 1.23 V (vs. reversible hydrogen electrode, RHE), under AM 1.5 G, which is 2.6 times of pure α-Fe2O3. Systematic studies reveal that the remarkable PEC performance is attributed to accelerated surface OER kinetics and enhanced carrier separation efficiency. This work provides a feasible strategy to enhance the PEC performance of hematite photoanodes.
Overall water photo-splitting is a prospective ideal pathway to produce ultra-clean H2 energy by semiconductors. However, the band structure of many semiconductors cannot satisfy the requirement of H2 and O2 production at the same time. Herein, we illustrate that carbon dots (CDs)/Bi2WO6 photocatalyst with compensatory photo-electronic effect has enhanced activity for overall water photo-splitting without any sacrificial agent. In this complex photocatalytic system, the photo-potential provided by CDs makes the CDs/Bi2WO6 (C-BWO) composite could satisfy the band structure conditions for overall water photo-splitting. The C-BWO composite (3 wt% CDs content) exhibits optimized hydrogen evolution (oxygen evolution) of 0.28 μmol/h (0.12 μmol/h) with an approximate 2:1 (H2: O2) stoichiometry at normal pressure. We further employed the in-situ transient photovoltage (TPV) technique to study the photoelectron extraction and the interface charge transfer kinetics of this composite catalyst.
Recently, photodynamic therapy (PDT) has been extensively applied in clinical and coadjuvant treatment of various kinds of tumors. However, the photosensitizer (PS) of PDT still lack of high production of singlet oxygen (1O2), low cytotoxicity and high biocompatibility. Herein, we propose a facile method for establishing a new core-shell structured Sn nanocluster@carbon dots (CDs) PS. Firstly, Sn4+@S-CDs complex is synthesized using the sulfur-doped CDs (S-CDs) and SnCl4 as raw materials, and subsequently the new PS (Sn nanocluster@CDs) is obtained after vaporization of Sn4+@S-CDs solution. Remarkably, the obtained Sn nanocluster@CDs show an enhanced fluorescence as well as a higher 1O2 quantum yield (QY) than S-CDs. The high 1O2 QY (58.3%) irradiated by the LED light (400–700 nm, 40 mW/cm2), induce the reduction of 4T1 cancer cells viability by 25%. More intriguingly, no visible damage happens to healthy cells, with little impact on liver tissue due to renal excretion, both in vitro and in vivo experiments demonstrate that Sn nanocluster@CDs may become a promising PS, owning a high potential for application in PDT.
Carbon dots (Cdots) has been proved to possess the catalytic decomposition of H2O2 in the photocatalytic system. It is a potential photo-Fenton catalyst. Since multiple emissive Cdots have different light response range. There is rarely investigation on the performance of Cdots based photo-Fenton on the light wavelength. Herein, blue, green and red emissive carbon dots were synthesized from the different ratio of o-phenylenediamine and catechol by the solvothermal method. They exhibit different light adsorption range from UV to visible light. Furthermore, the photo-Fenton reactivity of Cdots was studied for catalyzing the decomposition of H2O2 to generate free hydroxyl radicals and consequently applying for the removal of methyl blue. The results exhibit that Cdots with the broader light adsorption rang possess the stronger catalytic activity for the photo-Fenton reaction. The H2O2 decomposition rate of red emissive Cdots is 0.074 min−1, which is 2.64 and 1.46 times than the blue and green emissive Cdots, respectively. And the radical detection results confirm that the photo-Fenton happens in the reaction. In addition, the Cdots photo-Fenton can be carried out in the broad pH range from acidic to basic solution, which has a great potential to treat wastewater in the neutral system.
Borylative cyclization of E-3-arylallyl carbamoyl chlorides is achieved through copper catalyzed intramolecular carboboration with B2pin2. 2-Aryl-3-boryl-γ-lactams are formed with exclusive cis-diastereoselectivity. CuBr-Dppp combination gives the best outcomes. The substrate scope is profiled.
Recognition features of glycine (Gly) with cucurbit[5]uril (Q[5]) and cucurbit[6]uril (Q[6]) both in aqueous solution and solid state were investigated by 1H NMR spectroscopy and X-ray crystallography. 1H NMR data indicate that the Gly is located outside of the portals of the Q[5], exhibiting exo binding with the Q[5]. In the case of the Q[6], the Gly shows endo binding or a dual binding mode (endo and exo binding) with the host, which depends on the amount of the host in the aqueous solution. X-ray crystallography clearly display that the Gly forms 2:1 exclusion complex with the Q[5], and 2:1 inclusion complex with the Q[6]. Interestingly, hydrogen bondings between the encapsulated Gly molecules in the Q[6] were observed.
Chiral α-substituted 1, 3-dihydroisobenzofurans are key scaffolds in a number of bioactive natural products and synthetic pharmaceuticals. However, catalytic asymmetric approaches have been rarely developed. Here, a redox deracemization technology is adopted to address the catalytic asymmetric synthesis. A broad range of α-aryl substituted 1, 3-dihydroisobenzofurans are effectively deracemized in high efficiency with excellent ee. α-Alkynyl substituted ethers were also compatible with the deracemization technology.
A novel route for tandem C–C/C–N formation, annulation and aromatization of hydrazones with 1, 2-dichloroethane to synthesize 1H-pyrazoles has been developed. Furthermore, the 1, 2-dichloroethane serves as alkylation reagent in good to excellent yields. This methodology features mild reaction conditions and good functional group tolerance, providing a direct approach for the preparation of 1H-pyrazoles.
When treated with an alkoxide base like t-BuOK in aprotic solvent, N-diphenylmethyl imino oxindoles, made conveniently through condensation of corresponding isatins with N-diphenylmethyl amine, are deprotonated to form azaallyl anions. Allylation and alkylation of this type of intermediates proceed smoothly with diverse C-electrophiles. Acidic work up finishes 3-amino-3-allyl/alkyl oxindoles. The overall transformation equals to an umpolung process at the C3 of isatins.