Latest ArticlesNon-fused ring electron acceptors (NFREAs) have a broad application prospect in the commercialization of organic solar cells (OSCs) due to the advantages of simple synthesis and low cost. The selection of intermediate block cores of non-fused frameworks and the establishment of the relationship between molecular structure and device performance are crucial for the realization of high-performance OSCs. Herein, two A-D-A'-D-A type NFREAs namely CBTBO-4F and CBTBO-4Cl, constructed with a novel electron-deficient block unit N-(2-butyloctyl)-carbazole[3,4-c: 5,6-c]bis[1,2,5]thiadiazole (CBT) and bridging unit 4,4-bis(2-ethylhexyl)-4H-cyclopenta[2,1-b: 3,4-b']dithiophene (DTC) coupling with different terminals (IC-2F/2Cl), were designed and synthesized. The two NFREAs feature broad and strong photoresponse from 500 nm to 900 nm due to the strong intramolecular charge transfer characteristics. Compared with CBTBO-4F, CBTBO-4Cl shows better molecular planarity, stronger crystallinity, more ordered molecular stacking, larger van der Waals surface, lower energy level and better active layer morphology, contributing to much better charge separation and transport behaviors in its based devices. As a result, the CBTBO-4Cl based device obtains a higher power conversion efficiency of 10.18% with an open-circuit voltage of 0.80 V and a short-circuit current density of 21.20 mA/cm2. These results not only demonstrate the great potential of CBT, a new building block of the benzothiazole family, in the construction of high-performance organic conjugated semiconductors, but also suggest that the terminal chlorination is an effective strategy to improve device performance.
The oxalate-phosphate polyanion-mixed cathode materials are promising for sodium-ion batteries (SIBs) due to their unique open-framework structures and high voltage property. However, materials of this type generally contain crystal water molecules in the lattice frameworks, which may affect their energy storage properties. This work aims to disclose the impacts of crystal water on physiochemical and electrochemical properties of Na2(VO)2(HPO4)2(C2O4)·2H2O (NVPC-W). It shows that the water molecules can be eliminated by vacuum drying at 150 ℃. The elimination of water molecules does not change the crystal phase of the material, while the obtained Na2(VO)2(HPO4)2(C2O4) (NVPC) exhibits significant improvements in cycling stability, Coulombic efficiency, as well as rate performances. Kinetics analysis indicates that the existence of lattice water molecules hinders sodium-ion diffusion and promotes the degradation of electrodes. We believe the findings can help to develop high-performance cathode materials.
Brookhart-type α-diimine nickel and palladium catalysts have been extensively studied over the past several decades; however, the heterogenization of these metal complexes has received much less attention. In this contribution, we installed a trifluoroborate potassium substituent on an α-diimine framework. The ionic nature of trifluoroborate potassium endowed the α-diimine nickel complex with a strong affinity for the SiO2 support, while its electron-donating nature enhanced the catalyst stability and polyethylene molecular weight. In the presence of only 100 equiv. of Et2AlCl cocatalyst, the SiO2-supported catalyst demonstrated significantly better performance than its homogeneous analog during ethylene polymerization, with extremely high activity (1.42–6.53 × 107 g mol−1 h−1) and high thermal stability. The heterogeneous system led to the formation of high-molecular-weight polyethylenes (Mn 142, 500–732, 800 g/mol), narrow polydispersities (2.18–3.00), tunable branching densities (21–64 per 1000 carbon atoms), and great mechanical properties. Moreover, the efficient copolymerization of ethylene with comonomers such as methyl 10-undecenoate, 6-chloro-1-hexene or 5-hexenylacetate was achieved. These superior properties enabled by the trifluoroborate potassium moiety may inspire its applications in other polymerization catalyst systems.
Herein, we developed for the first time two carboxylic acid based intrinsic proton conductors (COOH-COF-1 and COOH-COF-2) via pre-assembly approach. The obtained COOH-COF-1 and COOH-COF-2 not only show outstanding chemical and thermal stabilities, but also exhibit superhigh intrinsic proton conductive behaviors. Especially, the intrinsic proton conductivity of COOH-COF-2 is up to 2.6 × 10−3 S/cm at 353 K and 98% RH, which is the highest value among all the reported acid functionalized COFs. This work lights up the way for the rational design of functional COFs with remarkably intrinsic proton conducting performance and related practical applications.
The rapid evolution of portable and wearable electronic devices has fueled the development of smart functional textiles that are able to conduct electricity, sense body movements, or store energy. One main challenge inhibiting the further development of functional textile-based electronics is the lack of robust functional fibers with suitable electrical, electrochemical and sensing functionalities. MXenes, an emerging family of two-dimensional (2D) materials, have shown to be promising candidates for producing functional fibers due to their exceptional electrical and electrochemical properties combined with solution processability. The unique ability of MXenes to readily form liquid crystal phases in various solvents has allowed them to generate additive-free fibers using a wet spinning process. In this work, we review the recent exciting developments in the fabrication of neat MXenes fibers and present a critical evaluation of practical challenges in MXenes processing that influence the macroscale material properties and the performance of the subsequent devices. We also provide our assessment for the future opportunities and challenges in producing MXene fibers to help pave the way for their widespread use in advanced wearable applications.
Small molecule activators could equally provide powerful tools as inhibitors do for interrogating cellular signal transduction. However, targeted protein activation is chemically challenging. Developing activators against Src homology region 2 domain-containing phosphatase-1 (SHP-1) to block STAT3 pathway represents a promising strategy for DLBCL therapy. Here we reported a new class of thieno[2,3-b]quinoline-procaine hybrid molecules as SHP-1 allosteric activators. The representative hybrid compound 3b displayed SHP-1 activating effect with EC50 of 5.48 ± 0.28 µmol/L. Further investigations confirmed that 3b allosterically interacted with SHP-1, switched it from close to open conformation, blocked SHP-1/p-STAT3 pathway, induced apoptosis and inhibited ABC-DLBCL cell proliferation in vitro, and delayed tumor growth in the xenograft model of SU-DHL-2. Overall, this work offered a novel paradigm to develop SHP-1 allosteric activators through chemical space evolution of PTPs inhibitors, and firstly validated the therapeutic strategy that directly activating SHP-1 alone could be a potential therapy against ABC-DLBCL via blocking STAT3 pathway.
Opportunities coexist with challenges for the development of carbon-based cathodes with a high energy density applied for zinc ion hybrid capacitors (ZIHCs). In the present study, a facile and effective surface engineering approach is demonstrated to greatly improve the energy storage ability of commercial carbon paper (CP) in ZIHC. Benefiting from the introduced oxygen functional groups, larger surface area and improved surface wettability upon air calcination, the assembled aqueous ZIHC with the functionalized carbon paper (FCP) exhibits a much higher areal capacity of 0.22 mAh/cm2 at 1 mA/cm2, outperforming the counterpart with blank CP by over 5000 times. More importantly, a superior energy density and power density of 130.8 µWh/cm2 and 7460.5 µW/cm2, are respectively delivered. Furthermore, more than 90% of the initial capacity is retained over 10000 cycles. This surface engineering strategy to improve the energy storage capability is potentially applicable to developing a wide range of high-energy carbon electrode materials.
Chiral high-nuclearity lanthanide (4f) clusters have shown fantastic properties in various fields. However, their synthesis is still of great challenge. Herein, we report two pairs of enantiomers of high-nuclearity Dy-oxo clusters synthesized through in situ strategy. They are [Dy18(R/SHftp)4 (R/SH2btp)4(μ2-OH)8(μ3-OH)20(μ6-O)(NO3)4(μ-H2O)8]·[solvents] (1R and 1S) and [Dy9(R/SHftp)2 (R/SH2btp)2(OAc)6(μ3-OH)10(H2O)6](OAc)·[solvents] (2R and 2S), where R/SHftp2− and R/SH2btp3− represent in situ formed 2-formyl-6-[N-(threonine)iminomethyl]-4-methylphenol and 2,6-bis[N-(threonine)iminomethyl]-4-methylphenol anions, respectively. These in situ formed clusters were endowed with not only homochirality via introducing R/SHftp2− and R/SH2btp3− ligands, but also rich oxo-bridges by controlling the hydrolysis of DyⅢ ions. Different anions from DyⅢ salts further induced structural variation between two sets of clusters. 1R and 1S feature an unprecedent four-blade propeller shaped {Dy18} core, whose centered octahedral {Dy6} unit are surrounded by four triangular {Dy3} units. Strikingly, they represent the second largest chiral 4f cluster species so far. 2R and 2S display a sandglass-like {Dy9} skeleton that consist of two square pyramid {Dy5} units sharing a DyⅢ vertex. Magnetic investigation revealed possible antiferromagnetic interactions between the DyⅢ centers in these clusters.
The liquid leakage and weak solar absorption capacity of organic phase change materials (PCMs) seriously hinder the efficient utilization of solar energy and thermal energy storage. To address these issues, we prepared nanoporous metal organic framework (Ni-MOF) for the vacuum infiltration of paraffin wax (PW), followed by the coating of solar-absorbing functional polydopamine (PDA) on the surface of PW@MOF for photothermal conversion and storage. As an efficient photon harvester, PDA coating endows PW@MOF/PDA composite PCMs with excellent photothermal conversion and storage properties due to the robust broadband solar absorption capability in the UV–vis region. Resultantly, our prepared PW@MOF/PDA composite PCMs exhibit a high photothermal conversion and storage efficiency of 91.2%, while that of PW@MOF composite PCMs is only zero. In addition, PW@MOF/PDA composite PCMs also exhibit excellent thermal stability, shape stability, energy storage stability, and photothermal conversion stability. More importantly, this coating strategy is universal by integrating different MOFs and solar absorbers, showing the potential to accelerate the major breakthroughs of high-efficiency MOF-based photothermal composite PCMs in solar energy utilization.
Unraveling the catalytic reaction mechanism is a long-term challenge for developing efficient catalysts. The blooming bimetallic catalyst have enabled to activate inert bonds and realize complex C-C formation. Herein, we theoretically discover a dual-phosphinito bridged hetero-bimetallic species that verified by NMR experiments. Our results indicate only dual-phosphinito Ni-Al model can be an active catalyst in asymmetric cycloadditions via C-C activation and C-H activation, which can well rationalize the experimental observations for both reactivity and stereo-selectivity. An unprecedented tandem redox dehydrogenation mechanism was revealed to control the formation of this active species overriding the inherent basicity. Synergistic Lewis acid and eg orbital interactions, including dz2 orbital reoccupation and dx2-y2 orbital recombination, were disclosed to understand both thermodynamic and kinetic advance of dual-bridged model, displaying feasible redox properties.