The past few years have witnessed the rapid development of carbon dots (CDs) due to their outstanding optical properties and a wide range of applications. However, the design and control of CDs with long-wavelength multicolor emission are still huge challenges to be addressed for their practical use in different fields. Here, novel nitrogen-doped multiple-core@shell-structured AC-CDs with tricolor emissions of red, green, and blue were constructed via one-pot hydrothermal method from 5-amino-1,10-phenanthroline and citric acid as reactants and the growth process of AC-CDs was monitored with the reaction time in the synthetic system. The origin of different fluorescence emissions was explored using the unique coordination ability of the surface groups of AC-CDs. An obvious concentration dependence of fluorescent properties was observed for the as-prepared AC-CDs, and a highly fluorescent quantum yield (QY) of 67% for red emission at 630 nm can be obtained by adjusting concentration of AC-CDs. The pure white-light emission (0.33, 0.33; Commission Internationale de l'Elcairage coordinate) was carried out from single carbon dot with QY of 29% through regulation of the excitation and concentration of multiple-core@shell-structured AC-CDs. In addition, because of their excellent photoluminescent properties, the white-emitting AC-CDs as emitting phosphor can be easily used in the fabrication of white-light-emitting diode with good anti-photobleaching and temperature stability.
Lithiophilic sites with high binding energy to Li have shown the capability to guide uniform Li deposition, however, the irreversible reaction between Li and lithiophilic sites causes a loss of lithiophilicity. Herein, the concept of using reversible lithiophilic sites, such as single‐atoms (SAs) doped graphene, as a host, is systematically inspected in the context of Li metal battery (LMB) performance. Here, it is proposed that the binding energy to Li atoms should be within a certain threshold range, i.e., strong enough to inhibit Li dendrite growth and weak enough to avoid host structure collapse. Six kinds of SAs are utilized; doped 3D graphene, nitrogen‐doped 3D graphene, and pure 3D graphene, whose performance in LMBs are compared with each other. It is discovered that the SA‐Mn doped 3D graphene (SAMn@NG) has the most reversible lithiophilic site, in which adsorption strength with Li is suitable to guide uniform deposition and keep the structure stable. During Li plating/stripping, the changes of the atomic structures in SAMn@NG, such as change of bond length and bond angle around Mn atoms are much smaller than those on SAZr@NG, although its binding energy is higher, enabling a much‐improved battery performance in SAMn@NG. This work provides a new insight to design lithiophilic sites in LMBs.
The absence of targeted, single treatment methods produces low therapeutic value for treating cancers. To increase the accumulation of drugs in tumors and improve the treatment effectiveness, near-infrared 808 nm photothermal responsive dual aptamers-targeted docetaxel (DTX)-containing nanoparticles is proposed. In this system, DTX and NH HCO are loaded in thermosensitive liposomes. The surface of liposomes is coated with gold nanoshells and connected with sulfydryl (SH) modified AS1411 and S2.2 aptamers. The nanosystem has good biocompatibility and uniform size (diameter about 200 nm). The drug is rapidly released, reaching a maximum amount (84%) at 4 h under 808 nm laser irradiation. The experiments conducted in vitro and in vivo demonstrate the nanosystem can synergistically inhibit tumor growth by combination of chemotherapy, photothermal therapy, and biological therapy. Dual ligand functionalization significantly increases cellular uptake on breast cancer cell line (MCF-7) cells and achieves ultrasound imaging (USI) at tumor site. The results indicate that this drug delivery system is a promising theranostic agent involving light-thermal response at tumor sites, dual ligand targeted triplex therapy, and USI.
Two novel diimine rhenium(I) carbonyl complexes with the formula [Re(CO)(3)(L)Br], where L = 1-(4-5'-phenyl-1,3,4-oxadiazolylbenzyl)-2-pyridinylbenzoimidazole (1) and 1-(4-carbazolylbutyl)-2-pyridinylbenzoimidazole (2), have been successfully synthesized and characterized by elemental analysis, (1)H NMR, and IR spectra. Their electrochemical, photophysical, and electroluminescent behaviors, along with the X-ray crystal structure analysis of 2, are also described. White electrophosphorescent devices were fabricated using 1 and 2 as emitters. The devices based on carbazole-containing (hole-transporting group) 2 with the structure ITO/m-MTDATA (30 nm)/NPB (20 nm)/2:CBP (8%, 30 nm)/Bphen (20 nm)/Alq(3) (20 nm)/LiF (0.8 nm)/Al (200 nm) exhibit Commission Internationale de L'Eclairage coordinates of x = 0.34, y = 0.33 with a maximum brightness of 2300 cd/m(2) at 580 mA/cm(2). When a brightness of 1500 cd/m(2) appears at 230 mA/cm(2), the devices based on 10 wt % 2 still possess 56% of the maximum efficiency which appeared at 2.7 mA/cm(2). These performances are among the best reported for devices using Re(I) complexes as emitters. By comparison of the electroluminescent properties of the devices based on 1 and 2, we conclude that the introduction of the carbazole group into the ligand improves the performance of 1-doped devices.
Supramolecular self-assembly is an effective method for constructing complex ordered aggregates with specific functions by noncovalent bonding. However, silver nanoclusters (NCs) have rarely been explored in the self-assembly of nanoscale building blocks, and the noncovalent forces (electrostatic, hydrogen-bonding, π−π-stacking interactions, etc.) and argentophilic interactions [Ag(I)•••Ag(I)] are crucial in directing to the supramolecular self-assembly of Ag(I) compounds. Here, we used silver NCs (Ag 9 -NCs, [Ag 9 (mba) 9 ], where H 2 mba = 2mercaptobenzoic acid) as the model cluster to interact with succinic acid (SA) to construct a nanofiber structure. The formation of highly ordered nanofibers is the result of SA-modified peripheral ligands of Ag 9 -NCs. Under the action of noncovalent forces (hydrogen-bonding, π−πstacking, and hydrophobic interactions), the reconstruction of this ordered structure not only increases the content of Ag(I) species in the protective shell of Ag 9 -NCs but also provides the possibility for directional argentophilic interactions [Ag(I)•••Ag(I)]. More interestingly, the compact structure and effective argentophilic interactions in the nanofibers synergistically achieve aggregation-induced emission, thereby inducing the emission of phosphorescence, which can be used as a temperature-controlled detector. Moreover, the orange-red Ag 9 -NCs/SA xerogels, together with commercial phosphor, can also be used as a phosphor to produce white-light-emitting-diode color conversion materials.
Lithium (Li) metal is considered as one of the best anode materials due to its high theoretical capacity and low reduction potential. However, its practical application is restricted by uneven Li metal dendrite growth. Herein, vertically aligned Ti3C2Tx MXene nanosheet arrays synthesized by a facile ice template assisted blade coating method are adopted to regulate Li metal nucleation and guide Li metal deposition. This kind of vertical structure exhibits low tortuosity that can achieve homogeneous and fast Li transport. In addition, the rich F and O groups on the Ti3C2Tx surface are conducive to the formation of a uniform solid–electrolyte interphase layer, which plays an important role in regulating the nucleation and growth of Li metal. Consequently, the vertically aligned Ti3C2Tx electrodes achieve high Coulombic efficiencies (98.8%) for more than 450 cycles at a fixed areal capacity of 1.0 mAh cm−2 with a current density of 1.0 mA cm−2. Moreover, it can maintain stable lithium plating/striping behaviors even at an ultrahigh current density of 5.0 mA cm−2 and high areal capacity of 5.0 mAh cm−2. Furthermore, full batteries (LiFePO4 as cathode) paired with these vertically aligned Ti3C2Tx electrodes show superior stability and rate performance than the horizontally aligned Ti3C2Tx electrodes.
Recently, nanoplatforms with multiple functions, such as tumor-targeting drug carriers, MRI, optical imaging, thermal therapy etc., have become popular in the field of cancer research. The present study reports a novel multi-functional liposome for cancer theranostics. A dual targeted drug delivery with radiofrequency-triggered drug release and imaging based on the magnetic field influence was used advantageously for tumor multi-mechanism therapy. In this system, the surface of fullerene (C60) was decorated with iron oxide nanoparticles, and PEGylation formed a hybrid nanosystem (C60-Fe3O4-PEG2000). Thermosensitive liposomes (dipalmitoylphosphatidylcholine, DPPC) with DSPE-PEG2000-folate wrapped up the hybrid nanosystem and docetaxel (DTX), which were designed to combine features of biological and physical (magnetic) drug targeting for fullerene radiofrequency-triggered drug release. The magnetic liposomes not only served as powerful tumor diagnostic magnetic resonance imaging (MRI) contrast agents, but also as powerful agents for photothermal ablation of tumors. Furthermore, a remarkable thermal therapy combined chemotherapy multi-functional liposome nanoplatform converted radiofrequency energy into thermal energy to release drugs from thermosensitive liposomes, which was also observed during both in vitro and in vivo treatment. The multi-functional liposomes also could selectively kill cancer cells in highly localized regions via their excellent active tumor targeting and magnetic targeted abilities.
MXene has been found as a good host for lithium (Li) metal anodes because of its high specific surface area, lithiophilicity, good stability with lithium, and the in situ formed LiF protective layer. However, the formation of Li dendrites and dead Li is inevitable during long‐term cycle due to the lack of protection at the Li/electrolyte interface. Herein, a stable artificial solid electrolyte interface (SEI) is constructed on the MXene surface by using insulating g‐C3N4 layer to regulate homogeneous Li plating/stripping. The 2D/2D MXene/g‐C3N4 composite nanosheets can not only guarantee sufficient lithiophilic sites, but also protect the Li metal from continuous corrosion by electrolytes. Thus, the Ti3C2Tx/g‐C3N4 electrode enables conformal Li deposition, enhanced average Coulombic efficiency (CE) of 98.4%, and longer cycle lifespan over 400 cycles with an areal capacity of 1.0 mAh cm−2 at 0.5 mA cm−2. Full cells paired with LiFePO4 (LFP) cathode also achieve enhanced rate capacity and cycling stability with higher capacity retention of 85.5% after 320 cycles at 0.5C. The advantages of the 2D/2D lithiophilic layer/artificial SEI layer heterostructures provide important insights into the design strategies for high‐performance and stable Li metal batteries.
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