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The rapid development of modern electronic devices increasingly requires thermal management materials with controllable electrical properties, ranging from conductive and dielectric to insulating, to meet the needs of diverse applications. However, highly thermally conductive materials usually have a high electrical conductivity. Intrinsically highly thermally conductive, but electrically insulating materials are still limited to a few kinds of materials. To overcome the electrical-thermal conductance trade-off, here, we report a facile Pechini-based method to prepare multiple core (metal)/shell (metal oxide) engineered fillers, such as aluminum-oxide-coated and beryllium-oxide-coated Ag microspheres. In contrast to the previous in situ growth method which mainly focused on small-sized spheres with specific coating materials, our method combined with ultrafast joule heating treatment is more versatile and robust for varied-sized, especially large-sized core-shell fillers. Through size compounding, the as-synthesized core-shell-filled epoxy composites exhibit high isotropic thermal conductivity (∼3.8 W m -1 K -1 ) while maintaining high electrical resistivity (∼10 12 Ω cm) and good flowability, showing better heat dissipation properties than commercial thermally conductive packaging materials. The successful preparation of these core-shell fillers endows thermally conductive composites with controlled electrical properties for emerging electronic package applications, as demonstrated in circuit board and battery thermal management.

Breast-conserving surgery (BCS) is the standard of care for early breast cancer patients, while the high ratio of reoperation is still a challenge due to inaccurate margin assessments. In patients with locally advanced or advanced breast cancer, radiotherapy is an important treatment for local control or improvement of quality of life. However, enhancing sensitization to radiotherapy is an unmet medical need. To solve the above clinical predicaments, a glutathione (GSH) exhausting virus-like silicon dioxide nanoprobe with Gd coating and folic acid (FA) modification is designed. After loading ICG in the mesopores, the VGd@ICG-FA probe efficiently targets tumor cells with high resolution, due to its virus-like morphology and folate acid anchoring. Especially, the fabricated nanoprobe enables the identification of tiny cancers and navigates precise surgery under NIR-II fluorescence imaging. Moreover, after the nanoprobes enter into the cytoplasm of cancer cells, tetrasulfide linkages in the silica framework are broken under the triggering of high GSH concentrations. In turn, the broken framework exhausts GSH to disrupt intracellular reactive oxygen species (ROS) homeostasis, and Gd produces more ROS under radiotherapy, further activating ferroptosis, and resulting in the enhancement of radiotherapy in breast cancer. Therefore, our nanoprobe exhibits tremendous potential as a NIR-II fluorescence imaging agent with no systematic side effects for precise cancer surgery and nanotherapeutics for boosting radiation sensitivity in future clinical translation of breast cancer.

The electrocatalytic nitrogen reduction reaction (NRR) has been regarded as a promising strategy for producing ammonia (NH 3 ) at ambient conditions. However, the development of the NRR is severely hindered by the difficult adsorption and activation of N 2 on the catalyst surface and the competitive hydrogen evolution reaction (HER) due to the lack of efficient NRR electrocatalysts. Herein, Mo 2 C-MoO 2 heterostructure quantum dots embedded in reduced graphene oxide (RGO) are proposed as efficient catalysts for the electrocatalytic NRR. The ultrasmall size of the quantum dot is beneficial for exposing the active sites for the NRR, and the synergetic effect of Mo 2 C and MoO 2 can promote N 2 adsorption and activation and suppress the competitive HER simultaneously. As a result, a well-balanced NRR performance is achieved with a high NH 3 yield rate of 13.94 ± 0.39 μg h -1 mg -1 at -0.15 V vs RHE and a high Faradaic efficiency of 12.72 ± 0.58% at -0.1 V vs RHE. Density functional theory (DFT) calculations reveal that the Mo 2 C (001) surface has a strong N 2 adsorption energy of -1.47 eV with the side-on configuration, and the N≡N bond length is elongated to 1.254 Å, indicating the enhanced N 2 adsorption and activation on the Mo 2 C surface. On the other hand, the low Δ G H* for HER over the MoO 2 (-111) surface demonstrates the impeded HER process for MoO 2 . This work may provide effective catalyst-design strategies for enhancing the electrocatalytic NRR performance of Mo-based materials.

Efficient thermal transportation in a preferred direction is highly favorable for thermal management issues. The combination of 3D printing and two-dimensional (2D) materials such as graphene, BN, and so on enables infinite possibilities for hierarchically aligned structure programming. In this work, we report the formation of the asymmetrically aligned structure of graphene filled thermoplastic polyurethane (TPU) composites during 3D printing process. The as-printed vertically aligned structure demonstrates a through-plane thermal conductivity (TC) up to 12 W m -1 K -1 at 45 wt % graphene content, which is ∼8 times of that of a horizontally printed structure and surpasses many of the traditional particle reinforced polymer composites. The superior TC is mainly attributed to the anisotropic structure design that benefited from the preferable degree of orientation of graphene and the multiscale dense structure realized by finely controlling the printing parameters. Finite element method (FEM) confirms the essential impact of anisotropic TC design for highly thermal conductive composites. This study provides an effective way to develop 3D printed graphene-based polymer composites for scalable thermal-related applications such as battery thermal management, electric packaging, and so on.

Room-temperature self-healing and self-growing of the exoskeleton with aligned structures in insects has few analogs in synthetic materials. Insect cuticle, such as elytra in beetles, with a typical lightweight lamellar structure, has shown this capability, which is attributed to the accumulation of phenol oxidase with polyphenol and amine-rich compounds in the hard cuticle. In this study, laminar-structure-based intelligence is imitated by incorporating adaptable and growable pyrogallol (PG)-borax dynamic-covalent bonds into a poly(acrylamide)-clay network. The events that lead to crack formation and water accumulation quickly trigger the deprotection of PG. Subsequently, atmospheric O 2 , as a regeneration source, activates PG oxidative self-polymerization. Multiple permanent and dynamic cross-links, with the involvement of the sacrificed borax, and initiation of a series of intelligent responses occur. The fabricated composites with an aligned lamellar structure exhibit outstanding characteristics, such as air/water-triggered superstrong adhesion, self-repairing, self-sealing and resealing, and reprocessing. Moreover, the strategy endows the composites with a self-growing capability, which leads to a 4- to 10-fold increase in its strength in an outdoor climate (up to 51 MPa). This study could lead to advances in the development of air/water-responsive composite materials for applications such as adaptive barriers.

Tumor cell metabolism and tumor blood vessel proliferation are distinct from normal cells. The resulting tumor microenvironment presents a characteristic of hypoxia, which greatly limits the generation of oxygen free radicals and affects the therapeutic effect of photodynamic therapy. Here, we developed an oxygen-independent free radical generated nanosystem (CuFeSe 2 -AIPH@BSA) with dual-peak absorption in both near-infrared (NIR) regions and utilized it for imaging-guided synergistic treatment. The special absorption provides the nanosystem with high photothermal conversion efficiency and favorably matched photoactivity in both I and II NIR biological windows. Upon NIR light irradiation, the generated heat could prompt AIPH release and decompose to produce oxygen-independent free radicals for killing cancer cells effectively. The contrastive research results show that the enhanced therapeutic efficacy of NIR-II over NIR-I is principally due to its deeper tissue penetration and higher maximum permission exposure that benefits from a longer wavelength. Hyperthermia effect and the production of toxic free radicals upon NIR-II laser illumination are extremely effective in triggering apoptosis and death of cancer cells in the tumor hypoxia microenvironment. The high biocompatibility and excellent anticancer efficiency of CuFeSe 2 -AIPH@BSA allow it to be an ideal oxygen-independent nanosystem for imaging-guided and NIR-II-mediated synergistic therapy via systemic administration.

Paper-supported electrodes with high flexibility have attracted much attention in flexible Li-ion batteries. However, they are restricted by the heavy inactive paper substrate and large volume change during the lithiation-delithiation process, which will lead to low capacity and poor rate capability and cyclability. Converting the paper substrate to carbon fiber by carbonization can substantially eliminate the "dead mass", but it becomes very brittle. This study reports a water-steam selective etching strategy that successfully addresses these problems. With the help of steam etching, pores are created, and transition-metal oxides are embedded into the fiber. These effectively accommodate the volume change and enhances the kinetics of ion and electron transport. The pores release the mechanical stress from bending, ensuring the sufficient bendability of carbonized paper. Benefiting from these merits, the steam-etched samples show high flexibility and possess outstanding electrochemical performance, including ultra-high capacity and superior cycling stability with capacity retention over 100% after 1500 cycles at 2 A g -1 . Furthermore, a flexible Li-ion full battery using the steam-etched Fe 2 O 3 @CNF anode and LiFePO 4 /steam-etched CNF cathode delivers a high capacity of 623 mAh g -1 at 100 mA g -1 and stable electrochemical performances under the bent state, holding great promise for next-generation wearable devices.

High, stable, and modulatable ionic conductivity is important for many nanofluidic applications of layered two-dimensional (2D) membranes. In this study, we demonstrate a proton and ionic conductivity of the Ti 3 C 2 T x membrane that is orders of magnitude higher than that of bulk solution at low concentrations. Importantly, the membrane is highly stable in aqueous solution without any modification, due to the strong and attractive interlayer van der Waals interaction and weak electrostatic repulsive interaction. Furthermore, by exploiting the intrinsic photothermal property of MXene, we demonstrate that the ionic conductivity can be reversely, rapidly, and completely switched on or off with laser light. This study should prove MXene membrane as a suitable platform to study and utilize nanofluidic ion transport. It should also inspire future studies to manipulate the mass transport through 2D membranes using their inherent physicochemical properties.

Large-area (∼cm 2 ) films of vertical heterostructures formed by alternating graphene and transition-metal dichalcogenide (TMD) alloys are obtained by wet chemical routes followed by a thermal treatment at low temperature. In particular, we synthesized stacked graphene and W x Mo 1-x S 2 alloy phases that were used as hydrogen evolution catalysts. We observed a Tafel slope of 38.7 mV dec -1 and 96 mV onset potential (at current density of 10 mA cm -2 ) when the heterostructure alloy was annealed at 300 °C. These results indicate that heterostructures formed by graphene and W 0.4 Mo 0.6 S 2 alloys are far more efficient than WS 2 and MoS 2 by at least a factor of 2, and they are superior compared to other reported TMD systems. This strategy offers a cheap and low temperature synthesis alternative able to replace Pt in the hydrogen evolution reaction (HER). Furthermore, the catalytic activity of the alloy is stable over time, i.e., the catalytic activity does not experience a significant change even after 1000 cycles. Using density functional theory calculations, we found that this enhanced hydrogen evolution in the W x Mo 1-x S 2 alloys is mainly due to the lower energy barrier created by a favorable overlap of the d-orbitals from the transition metals and the s-orbitals of H 2 ; with the lowest energy barrier occurring for the W 0.4 Mo 0.6 S 2 alloy. Thus, it is now possible to further improve the performance of the "inert" TMD basal plane via metal alloying, in addition to the previously reported strategies such as creation of point defects, vacancies and edges. The synthesis of graphene/W 0.4 Mo 0.6 S 2 produced at relatively low temperatures is scalable and could be used as an effective low cost Pt-free catalyst.

In the theranostic field, a near-infrared (NIR) laser is located in the optical window, and up-conversion nanoparticles (UCNPs) could be potentially utilized as the imaging agents with high contrast. Meanwhile, copper sulfide (CuS) has been proposed as a photothermal agent with increased temperature under a NIR laser. However, there is still no direct and effective strategy to integrate the hydrophobic UCNPs with CuS until now. Herein, we propose an in situ growth routine based on the hydrophobic core/shell UCNPs combined with ultrasmall water-soluble CuS triggered by single 808 nm NIR irradiation as the theranostic platform. Hydrophobic NaYF 4 :Yb,Er@NaYF 4 ,Nd,Yb could be turned hydrophilic with highly dispersed and biocompatible properties through conjunction with transferred dopamine. The as-synthesized ultrasmall CuS (3 and 7 nm) served as a stable photothermal agent even after several laser-on/off cycles. Most importantly, comparing with the mix routine, the in situ growth routine to coat UCNPs with CuS is meaningful, and the platform is uniform and stable. Green luminescence-guided hyperthermia could be achieved under a single 808 nm laser, which was evidenced by in vitro and in vivo assays. This nanoplatform is applicable as a bioimaging and photothermal antitumor agent, and the in situ growth routine could be spread to other integration processes.

To integrate photodynamic therapy (PDT) with photothermal therapy (PTT) and chemotherapy for enhanced antitumor efficiency, we developed a mild and rational route to synthesize novel multifunctional GdOF:Ln@SiO2 (Ln = 10%Yb/1%Er/4%Mn) mesoporous capsules using strong up-conversion luminescent (UCL) GdOF:Ln as cores and mesoporous silica layer as shells, followed by modification with varied functional groups onto the framework. It was found that due to the codoped Yb/Er/Mn in GdOF, the markedly enhanced red emission can efficiently transfer energy to the conjugated PDT agent (ZnPc) which produces high singlet oxygen, and the incorporated carbon dots outside the shell can generate obvious thermal effect under 980 nm laser irradiation and also prevent the premature leaking of ZnPc. Simultaneously, the as-produced thermal effect can obviously enhance the doxorubicin (DOX) release, which greatly improves the chemotherapy, resulting in a synergistic therapeutic effect. The system exhibits drastically enhanced therapeutic efficiency against tumor growth, as demonstrated both in vitro and in vivo. Especially, the doped rare earth ions in the host endow the material with excellent UCL imaging, magnetic resonance imaging (MRI), and computed tomography (CT) imaging properties, thus realizing the target of multimodal imaging guided multiple therapies.

Graphene is theoretically a robust two-dimensional (2D) sp(2)-hybridized carbon material with high electrical conductivity and optical transparency. However, due to the existence of grain boundaries and defects, experimentally synthesized large-area polycrystalline graphene sheets are easily broken and can exhibit high sheet resistances; thus, they are not suitable as flexible transparent conductors. As described in this issue of ACS Nano, Tour et al. circumvented this problem by proposing and synthesizing a novel hybrid structure that they have named "rebar graphene", which is composed of covalently interconnected carbon nanotubes (CNTs) with graphene sheets. In this particular configuration, CNTs act as "reinforcing bars" that not only improve the mechanical strength of polycrystalline graphene sheets but also bridge different crystalline domains so as to enhance the electrical conductivity. This report seems to be only the tip of the iceberg since it is also possible to construct novel and unprecedented hybrid carbon architectures by establishing covalent interconnections between CNTs with graphene, thus yielding graphene-CNT hybrids, three-dimensional (3D) covalent CNT networks, 3D graphene networks, etc. In this Perspective, we review the progress of these carbon hybrid systems and describe the challenges that need to be overcome in the near future.

The isolation of few-layered transition metal dichalcogenides has mainly been performed by mechanical and chemical exfoliation with very low yields. In this account, a controlled thermal reduction-sulfurization method is used to synthesize large-area (~1 cm(2)) WS2 sheets with thicknesses ranging from monolayers to a few layers. During synthesis, WOx thin films are first deposited on Si/SiO2 substrates, which are then sulfurized (under vacuum) at high temperatures (750-950 °C). An efficient route to transfer the synthesized WS2 films onto different substrates such as quartz and transmission electron microscopy (TEM) grids has been satisfactorily developed using concentrated HF. Samples with different thicknesses have been analyzed by Raman spectroscopy and TEM, and their photoluminescence properties have been evaluated. We demonstrated the presence of single-, bi-, and few-layered WS2 on as-grown samples. It is well known that the electronic structure of these materials is very sensitive to the number of layers, ranging from indirect band gap semiconductor in the bulk phase to direct band gap semiconductor in monolayers. This method has also proved successful in the synthesis of heterogeneous systems of MoS2 and WS2 layers, thus shedding light on the controlled production of heterolayered devices from transition metal chalcogenides.