Latest ArticlesThrough-space charge transfer (TSCT) is regarded as an effective way to develop thermally activated delayed fluorescence (TADF) emitters. Based on this strategy, many molecular frameworks have been proposed, among which spirobased scaffolds have been extensively studied due to their unique advantages. In this work, we developed three emitters SPS, SPO, and SPON, which were constructed with the same donor and various acceptors to explore the influence of acceptor modulation at the C9 position of fluorene for spirostructure TSCT emitters. The results show that the acceptor with too weak electron-withdrawing ability will cause the emitter to not have TADF properties, while the acceptor with too much steric hindrance will weaken the face-to-face π-π stacking interaction between donor/acceptor (D/A). Since SPO balances the electron-withdrawing strength and steric hindrance of the acceptor, it achieves the highest external quantum efficiency (EQE) of 17.75%. This work shows that appropriate acceptor selection is essential for the TADF properties and high efficiency of the spirobased scaffold TSCT emitter
A series of linear poly(ethylene oxide)-b-poly(4-vinylbenzyl chloride)-b-poly(4-tert-butylstyrene) (PEO113-b-PVBC130-b-PtBSx or E113V130Tx) triblock terpolymers with various lengths x (=20, 33, 66, 104, 215) of PtBS block were synthesized via a two-step reversible addition-fragmentation chain transfer (RAFT) polymerization. The E113V130T triblock terpolymers were non-crystalline because the PVBC and PtBS blocks strongly hindered the crystallization of PEO block. The effects of PtBS block length x on the phase structures of E113V130Tx triblock terpolymers were investigated by combined techniques of small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM). It was found that with increasing x from 20 to 215, the phase structure of E113V130Tx triblock terpolymers became more ordered and changed from disordered structure, hexagonally-packed cylinder (HEX), hexagonally perforated layer (HPL), to lamellar (LAM) phase structures. Temperature-variable SAXS measurements showed that the HEX, HPL and LAM phase structures obtained for E113V130T66, E113V130T104 and E113V130T215 by thermal annealing, respectively, were thermodynamically stable in the temperature range of 30–170 ℃.
One-step assembly of organic-ligand modified Pd-Keggin-POMs has been rarely reported, so as for their applications in catalytic benzothiadiazole generation and derived cell-imaging probing. Herein, three Pd-Keggin-POMs (compounds 1–3) have been successfully synthesized via a one-step assembly strategy. Thus-obtained Pd-Keggin-POMs with well-defined structures and heterogeneous properties enable highly efficient catalytic benzothiadiazole generation. Specifically, compound 3 showed outstanding catalytic activities in Suzuki-Miyaura coupling reactions for the generation of benzothiadiazole derivatives (yields, 90%-97%) and was represented as one of the best catalysts reported to date. Consequently, the obtained benzothiadiazoles were used as the bio-probe for tracking lipid droplets in living-cells and exhibited large Stokes shifts (130 nm), low cytotoxicity and good targeting, which could be also applied to mark the distribution of LDs in living HeLa cells. Systematic investigations clearly decipher the functions of Pd-Keggin-POMs toward finding novel bio-probe materials, highlighting a new insight into the generation of sustainable materials in life-science.
MOF-based composites have aroused widespread concern due to their controllable morphology and pore characteristics. Nevertheless, the poor conductivity and volume expansion hinder its practical application in LIBs. Herein a classical structure HKUST-1, as the precursor, was used to fabricate quasi-Cu-MOF composite through a facile thermal decomposition strategy. The results showed that quasi-Cu-MOF composite had superior reversible specific capacity (627.5 mAh/g at 100 mA/g) and outstanding cycle stability (514.6 mAh/g at 500 mA/g after 400 cycles) as anodes for LIBs. The results demonstrated that the low-temperature calcination strategy played a significant role in morphology retaining during cycling and the derived copper framework play a crucial part in conductivity improvement. This work is helpful to the design of high-performance electrodes with advanced three-dimensional hierarchical structures.
Increasing the charging cut-off potential of lithium cobalt oxide (LiCoO2, LCO) can effectively improve the energy density of the lithium-ion batteries, which are the mainstream energy storage devices used in 3C electronic products. However, the continuous decomposition of the electrolyte and dissolution of Co from the electrode will occur at high-potential operation, which deteriorate the performances of LCO. Here, a cathode-electrolyte interface (CEI) layer containing MgF2 is constructed to enhance the electrochemical stability of LCO at 4.6 V (vs. Li+/Li). The Mg2+ added to the cathode gradually releases into the electrolyte during cycling, which forms a stable MgF2-rich protective layer. In addition, 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropylether (TTE) is added to the electrolyte acting as a F source to increase the content of MgF2 in the CEI layer. The MgF2-rich CEI layer effectively suppresses the decomposition of electrolyte components and the dissolution of Co of LCO, which makes the Li||LiCoO2 (Li||LCO) cell cycled stably at 3~4.6 V (vs. Li+/Li) in 200 cycles with a retention of 83.9%.
Aqueous zinc-ion batteries (ZIBs) has been regarded as a promising energy storage system for large-scale application due to the advantages of low cost and high safety. However, the growth of Zn dendrite, hydrogen evolution and passivation issues induce the poor electrochemical performance of ZIBs. Herein, a Na3Zr2Si2PO12 (NZSP) protection layer with high ionic conductivity of 2.94 mS/cm on Zn metal anode was fabricated by drop casting approach. The protection layer prevents Zn dendrites formation, hydrogen evolution as well as passivation, and facilitates a fast Zn2+ transport. As a result, the symmetric cells based on NZSP-coated Zn show a stable cycling over 1360 h at 0.5 mA/cm2 with 0.5 mAh/cm2 and 1000 h even at a high current density of 5 mA/cm2 with 2 mAh/cm2. Moreover, the full cells combined with V2O5-based cathode displays high capacities and high rate capability. This work offers a facile and effective approach to stabilizing Zn metal anode for enhanced ZIBs.
Quantum dots (QDs) based heterojunction is a candidate for the photocatalytic CO2 reduction, owing to the large extinction coefficient and easy modification of band structures. However, the van der Waals interaction causes the large charge resistance and strong recombination centers between QDs and host materials, which makes the poor photocatalytic performance. Herein, a covalent bonded CdSeTe QDs and NH2-UiO-66 heterojunction (NUC-x) is constructed through an acylamino (-CONH-). The results indicate that the acylamino between NH2-UiO-66 and CdSeTe QDs can serve as the transfer channels for the photogenerated charges and stabilize the QDs. The optimized NUC-1200 achieved a CO generation rate of 228.68 µmol/g, which is 13 and 4 times higher than that of NH2-UiO-66 and CdSeTe QDs, respectively. This work provides a new avenue for efficient and stable photocatalysis of QDs.
Fluoranthenes have attracted tremendous attention due to their unique optoelectronic properties and extensive applications. Although several synthetic methodologies have been developed for the preparation of fluoranthene derivatives, it is still unfavorable to functionalize the fluoranthene framework at different positions due to the relatively low selectivity and reactivity. Herein, a catalyst-free intramolecular [4 + 2] annulation between thiophenes and alkynes is developed towards the synthesis of fluoranthenes. Altogether 20 examples have been demonstrated using this method. Various functional groups can be precisely introduced into the fluoranthene skeleton at different positions by simply tuning the substituents on the thiophenes and alkynes. The conjugation of the fluoranthene can be facilely extended through different directions. Furthermore, the feasibility of this [4 + 2] annulation reaction is also investigated by density functional theory calculations. Therefore, this protocol provides not only a synthetic methodology towards fluoranthenes with substituents functionalized at different positions, but also an effective pathway to construct large polycyclic aromatic hydrocarbons containing fluoranthene moieties.
Two-dimensional electride Ca2N has strong electron transfer ability and low work function, which is a potential candidate for hydrogen evolution reaction (HER) catalyst. In this work, based on density functional theory calculations, we adopt two strategies to improve the HER catalytic activity of Ca2N monolayer: introducing Ca or N vacancy and doping transition metal atoms (TM, refers to Ti, V, Cr, Mn, Fe, Zr, Nb, Mo, Ru, Hf, Ta and W). Interestingly, the Gibbs free energy ΔGH* of Ca2N monolayer after introducing N vacancy is reduced to -0.146 eV, showing good HER catalytic activity. It is highlighted that, the HER catalytic activity of Ca2N monolayer can be further enhanced with TM doping, the Gibbs free energy ΔGH* of single Mo and double Mn doped Ca2N are predicted to be 0.119 and 0.139 eV, respectively. The present results will provide good theoretical guidance for the HER catalysis applications of two-dimensional electride Ca2N monolayer.
Local delivery of nanomedicines holds therapeutic promise for colorectal cancer (CRC). However, it presents tremendous challenges due to the existence of multiple physiological barriers, especially intracellular obstacles, including intracellular trafficking, subcellular accumulation, and drug release. Herein, we report a multifunctional nanoparticle (CMSNR) by wrapping the mesoporous silica nanorod with cell membrane derived from CRC cells for improved chemotherapy. Compared with their naked counterparts, the cell membrane endowed CMSNR with homotypic targeting and improved cellular uptake capacities. Due to the rod-like shape, CMSNR achieved superior colorectal mucus permeability, enhanced tumor accumulation, and boosted cellular uptake than their spherical counterparts. Moreover, the internalized CMSNR underwent robust intracellular trafficking and gained augmented motility toward the nucleus, leading to efficient perinuclear accumulation and a subsequent 5.6-fold higher nuclear accumulation of loaded drug than that of nanospheres. In the orthotopic colorectal tumor-bearing nude mice, rectally administrated mefuparib hydrochloride (MPH)-loaded CMSNR traversed the colorectal mucus, penetrated the tumor tissue, and successfully aggregated in the perinuclear region of cancer cells, thus exhibiting significantly improved antitumor outcomes. Our findings highlight the shape-based design of cell membrane-coated nanoparticles that can address sequential drug delivery barriers has a promising future in cancer nanomedicine.
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