Rational designing of the composition and structure of electrode material is of great significance for achieving highly efficient energy storage and conversion in electrochemical energy devices. ...Herein, MoS2/NiS yolk–shell microspheres are successfully synthesized via a facile ionic liquid‐assisted one‐step hydrothermal method. With the favorable interface effect and hollow structure, the electrodes assembled with MoS2/NiS hybrid microspheres present remarkably enhanced electrochemical performance for both overall water splitting and asymmetric supercapacitors. In particular, to deliver a current density of 10 mA cm−2, the MoS2/NiS‐based electrolysis cell for overall water splitting only needs an output voltage of 1.64 V in the alkaline medium, lower than that of Pt/C–IrO2‐based electrolysis cells (1.70 V). As an electrode for supercapacitors, the MoS2/NiS hybrid microspheres exhibit a specific capacitance of 1493 F g−1 at current density of 0.2 A g−1, and remain 1165 F g−1 even at a large current density of 2 A g−1, implying outstanding charge storage capacity and excellent rate performance. The MoS2/NiS‐ and active carbon‐based asymmetric supercapacitor manifests a maximum energy density of 31 Wh kg−1 at a power density of 155.7 W kg−1, and remarkable cycling stability with a capacitance retention of approximately 100% after 10 000 cycles.
MoS2/NiS yolk–shell microspheres exhibit prominent electrochemical performance for both overall water splitting and asymmetric supercapacitors, which can be attributed to the advanced structural features of the interface effect and hollow structure.
Layered antiferromagnetism is the spatial arrangement of ferromagnetic layers with antiferromagnetic interlayer coupling. The van der Waals magnet chromium triiodide (CrI3) has been shown to be a ...layered antiferromagnetic insulator in its few-layer form, opening up opportunities for various functionalities in electronic and optical devices. Here we report an emergent nonreciprocal second-order nonlinear optical effect in bilayer CrI3. The observed second-harmonic generation (SHG; a nonlinear optical process that converts two photons of the same frequency into one photon of twice the fundamental frequency) is several orders of magnitude larger than known magnetization-induced SHG and comparable to the SHG of the best (in terms of nonlinear susceptibility) two-dimensional nonlinear optical materials studied so far (for example, molybdenum disulfide). We show that although the parent lattice of bilayer CrI3 is centrosymmetric, and thus does not contribute to the SHG signal, the observed giant nonreciprocal SHG originates only from the layered antiferromagnetic order, which breaks both the spatial-inversion symmetry and the time-reversal symmetry. Furthermore, polarization-resolved measurements reveal underlying C2h crystallographic symmetry-and thus monoclinic stacking order-in bilayer CrI3, providing key structural information for the microscopic origin of layered antiferromagnetism. Our results indicate that SHG is a highly sensitive probe of subtle magnetic orders and open up possibilities for the use of two-dimensional magnets in nonlinear and nonreciprocal optical devices.
Graphene with massless Dirac fermions can have exceptionally strong third-order optical nonlinearities. Yet reported values of nonlinear optical susceptibilities for third-harmonic generation (THG), ...four-wave mixing (FWM) and self-phase modulation vary over six orders of magnitude. Such variation likely arises from frequency-dependent resonance effects of different processes in graphene under different doping. Here, we report an experimental study of THG and FWM in graphene using gate tuning to adjust the doping level and vary the resonant condition. We find that THG and sum-frequency FWM are strongly enhanced in heavily doped graphene, while the difference-frequency FWM appears just the opposite. Difference-frequency FWM exhibited a novel divergence towards the degenerate case in undoped graphene, leading to a giant enhancement of the nonlinearity. The results are well supported by theory. Our full understanding of the diverse nonlinearity of graphene paves the way towards future design of graphene-based nonlinear optoelectronic devices.
Artificial structures made of stacked two-dimensional crystals have recently been the focus of intense research activity. As in twisted or stacked graphene layers, these structures can show unusual ...behaviours and new phenomena. Among the various layered compounds that can be exfoliated, transition-metal dichalcogenides exhibit interesting properties governed by their structural symmetry and interlayer coupling, which are highly susceptible to stacking. Here, we obtain-by folding exfoliated MoS2 monolayers-MoS2 bilayers with different stacking orders, as monitored by second harmonic generation and photoluminescence. Appropriate folding can break the inversion symmetry and suppress interlayer hopping, evoking strong valley and spin polarizations that are not achieved in natural MoS2 bilayers of Bernal stacking. It can also enlarge the indirect bandgap by more than 100meV through a decrease in the interlayer coupling. Our work provides an effective and versatile means to engineer transition-metal dichalcogenide materials with desirable electronic and optical properties.
For centrosymmetric materials such as monolayer graphene, no optical second-harmonic generation (SHG) is generally expected, because it is forbidden under the electric-dipole approximation. Yet we ...observe a strong, doping-induced SHG from graphene, with its highest strength comparable to the electric-dipole-allowed SHG in noncentrosymmetric 2D materials. This novel SHG has the nature of an electric-quadrupole response, arising from the effective breaking of inversion symmetry by optical dressing with an in-plane photon wave vector. More remarkably, the SHG is widely tuned by carrier doping or chemical potential, being sharply enhanced at Fermi-edge resonances but vanishing at the charge neutral point that manifests the electron-hole symmetry of massless Dirac fermions. This striking behavior in graphene, which should also arise in graphenelike Dirac materials, expands the scope of nonlinear optics and holds the promise of novel optoelectronic and photonic applications.
Synergistic therapy that combines chemo‐, gene‐, or photothermal means shows great potential for enhancing the therapeutic effects on cancers. Tumor‐targeted nanoparticles based on a doxorubicin ...(DOX)‐gated mesoporous silica nanocore (MSN) encapsulated with permeability glycoprotein (P‐gp) small interfering RNA (siRNA) and a polydopamine (PDA) outer layer for DOX loading and folic acid decoration are designed. The multifunctional nanoplatform tactfully integrates chemo‐ (DOX), gene‐ (P‐gp siRNA), and photothermal (PDA layer) substances in one system. In vitro results reveal that DOX release behaviors are both pH‐ and thermal‐responsive and the release of co‐delivered P‐gp siRNA is also pH‐dependent due to the pH‐cleavable DOX gatekeeper on MSN. In addition, due to the near‐infrared light‐responsive PDA outer layer and folic acid conjugation, the nanoparticles exhibit outstanding photothermal activity and selective cell targeting ability. Subsequently, in vitro and in vivo antitumor experiments both demonstrate the enhanced antitumor efficacy of the multifunctional nanoparticles, indicating the significance of synergistic therapy combining chemo‐, gene‐, and photothermal treatments in one system.
A novel drug and siRNA codelivery system based on polydopamine‐coated drug‐self‐gated mesoporous silica is developed. This drug delivery platform possesses three different therapeutic effects: chemo‐, gene‐, and photothermal therapy. Moreover, this nanosystem with tumor‐targeting and pH‐responsive abilities is also endowed. The enhanced tumor therapy effect is demonstrated by both in vitro and in vivo studies.
Traditional treatments such as chemotherapy and surgery usually cause severe side effects and excruciating pain. The emergence of nanomedicines and minimally invasive therapies (MITs) has brought ...hope to patients with malignant diseases. Especially, minimally invasive nanomedicines (MINs), which combine the advantages of nanomedicines and MITs, can effectively target pathological cells/tissues/organs to improve the bioavailability of drugs, minimize side effects and achieve painless treatment with a small incision or no incision, thereby acquiring good therapeutic effects. In this review, we provide a comprehensive review of the research status and challenges of MINs, which generally refers to the medical applications of nanotechnology in photo-/ultrasound-/radiation-/magnetism-mediated therapy and imaging. Additionally, we also discuss their combined application in various fields including cancers, cardiovascular diseases, tissue engineering, neuro-functional diseases, and infectious diseases. The prospects, and potential bench-to-bedside translation of MINs are also presented in this review. We expect that this review can inspire the broad interest for a wide range of readers working in the fields of interdisciplinary subjects including (but not limited to) chemistry, nanomedicine, bioengineering, nanotechnology, materials science, pharmacology, and biomedicine.
This review systematically summarizes the research status, challenges, prospects, and potential bench-to-bedside translation of minimally invasive nanomedicines.
The great success achieved by the two highly-effective messenger RNA (mRNA) vaccines during the COVID-19 pandemic highlights the great potential of mRNA technology. Through the evolution of mRNA ...technology, chemistry has played an important role from mRNA modification to the synthesis of mRNA delivery platforms, which allows various applications of mRNA to be achieved both
in vitro
and
in vivo
. In this tutorial review, we provide a summary and discussion on the significant progress of emerging mRNA technologies, as well as the underlying chemical designs and principles. Various nanoparticle (NP)-based delivery strategies including protein-mRNA complex, lipid-based carriers, polymer-based carriers, and hybrid carriers for the efficient delivery of mRNA molecules are presented. Furthermore, typical mRNA delivery platforms for various biomedical applications (
e.g.
, functional protein expression, vaccines, cancer immunotherapy, and genome editing) are highlighted. Finally, our insights into the challenges and future development towards clinical translation of these mRNA technologies are provided.
This review highlights significant progress in mRNA delivery platforms and therapeutic applications from the view of chemistry. Insights into the challenges and future development towards clinical translation of mRNA therapeutics are also provided.
Rutile titanium dioxide (TiO2) is a promising photocatalyst due to its high thermodynamic stability and few intragrain defects. However, it has not yet achieved photocatalytic activity comparable to ...that of anatase TiO2 owing to its higher recombination rate of electron–hole pairs. To effectively separate the electron–hole pairs in rutile TiO2, a facet heterojunction (FH) structure to prolong the lifetime of the photogenerated electrons is proposed. Ultrathin TiO2 nanosheets with different facets are coated in situ onto TiO2 nanorod (NR) substrates, where FHs are built among the nanosheets as well as between the nanosheets and NR substrates. The as‐prepared rutile TiO2, with an FH structure (FH‐TiO2), serves as an effective photocatalyst for water splitting. More than 45 and 18 times higher photogenerated current density and H2 production rate, respectively, are obtained compared to those of pure rutile TiO2 NRs. Moreover, FH‐TiO2 delivers a 0.566 mmol g−1 h−1 H2 production rate even in pure water. This study offers important insights into the rational design of rutile TiO2 structures for highly efficient photocatalytic reactions.
Rutile TiO2 photocatalyst with facet heterojunction structure is designed for high‐performance hydrogen evolution. Benefiting from the enhanced electron–hole separation, the heterojunction structure sample delivers more than 45 and 18 times higher photocurrent density and H2 productive rate, respectively, compared to pure rutile TiO2 nanorods.
The photo-induced polymerization to covalently link metal-organic polyhedra (MOPs) by flexible polymer chains is reported for the first time, which endows MOPs with enhanced processability, ...dispersity, and hydrostability. The resultant hybrid material exhibits 9 times higher capacity and much better reusability than bulk MOPs in the adsorption of methylene blue.
Metal-organic polyhedra are covalently linked by flexible polymer chains through photopolymerization, endowing the materials with enhanced processability, dispersity, and hydrostability.
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