Various methods have been exploited to replicate nacre features into artificial structural materials with impressive structural and mechanical similarity. However, it is still very challenging to produce nacre-mimetics in three-dimensional bulk form, especially for further scale-up. Herein, we demonstrate that large-sized, three-dimensional bulk artificial nacre with comprehensive mimicry of the hierarchical structures and the toughening mechanisms of natural nacre can be facilely fabricated via a bottom-up assembly process based on laminating pre-fabricated two-dimensional nacre-mimetic films. By optimizing the hierarchical architecture from molecular level to macroscopic level, the mechanical performance of the artificial nacre is superior to that of natural nacre and many engineering materials. This bottom-up strategy has no size restriction or fundamental barrier for further scale-up, and can be easily extended to other material systems, opening an avenue for mass production of high-performance bulk nacre-mimetic structural materials in an efficient and cost-effective way for practical applications.

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Two-dimensional transition metal dichalcogenides (TMDs) emerged as a promising platform to construct sensitive biosensors. We report an ultrasensitive electrochemical dopamine sensor based on manganese-doped MoS2 synthesized via a scalable two-step approach (with Mn ~2.15 atomic %). Selective dopamine detection is achieved with a detection limit of 50 pM in buffer solution, 5 nM in 10% serum, and 50 nM in artificial sweat. Density functional theory calculations and scanning transmission electron microscopy show that two types of Mn defects are dominant: Mn on top of a Mo atom (MntopMo) and Mn substituting a Mo atom (MnMo). At low dopamine concentrations, physisorption on MnMo dominates. At higher concentrations, dopamine chemisorbs on MntopMo, which is consistent with calculations of the dopamine binding energy (2.91 eV for MntopMo versus 0.65 eV for MnMo). Our results demonstrate that metal-doped layered materials, such as TMDs, constitute an emergent platform to construct ultrasensitive and tunable biosensors.

Surface functionalization of metallic and semiconducting 2D transition metal dichalcogenides (TMDs) have mostly relied on physi- and chemi-sorption at defect sites, which can diminish the potential applications of the decorated 2D materials, as structural defects can have substantial drawbacks on the electronic and optoelectronic characteristics. Here, we demonstrate a spontaneous defect-free functionalization method consisting of attaching Au single atoms to monolayers of semiconducting MoS2(1H) via S-Au-Cl coordination complexes. This strategy offers an effective and controllable approach for tuning the Fermi level and excitation spectra of MoS2 via p-type doping and enhancing the thermal boundary conductance of monolayer MoS2, thus promoting heat dissipation. The coordination-based method offers an effective and damage-free route of functionalizing TMDs and can be applied to other metals and used in single-atom catalysis, quantum information devices, optoelectronics, and enhanced sensing.

Poly(ethylene glycol) (PEG)-grafted polyaniline (PANi) copolymers were prepared by incorporating a chlorine end-capped methoxy PEG (mPEGCl) of molecular weight of about 2000 onto the leucoemeraldine form of PANi via N-alkylation. The microstructures and compositions of the mPEG-grafted PANi (mPEG-g-PANi) copolymers were characterized by FT-IR, elemental analysis, UV-visible absorption spectroscopy, thermogravimetric (TG) analysis and X-ray photoelectron spectroscopy (XPS). The graft concentration (degree of N-alkylation) can be controlled by adjusting the molar feed ratio of mPEGCl to the number of repeat units of PANi. The mPEG-g-PANi copolymers showed enhanced solubility in common organic solvents and water. The electrical conductivity of the mPEG-g-PANi copolymer film decreased by a factor of 5 at the mPEG graft concentration of 0.05. The mPEGg-PANi copolymer with a high graft concentration was very effective in preventing platelet adhesion.

Low-temperature synthesis of two-dimensional (2D) transition metal dichalcogenides (TMDs) is a key challenge for their integration with complementary metal-oxide-semiconductor (CMOS) technology at ‘back-end-of-line (BEOL)’. Most low-temperature synthesis utilizes alkali salts, oxide-based metals, and methyl-group based chalcogen precursors which do not meet current BEOL requirements for contaminant-free manufacturing and process scalability. In this study, we benchmark a carbon and alkali salt-free synthesis of fully coalesced, stoichiometric 2D WSe2 films on amorphous SiO2/Si substrates at BEOL- compatible temperatures (475 °C) via gas-source metal-organic chemical deposition. This work highlights the necessity of a Se-rich environment in a kinetically limited growth regime for successful integration of low-temperature 2D WSe2. Atomic-scale characterization reveals that BEOL WSe2 is polycrystalline with domain size of ~200 nm and band gap of 1.8 eV. Back-gated and electrolyte double layer gated field-effect transistors (FETs) exhibit increased ON currents as high as 4 µA µm−1 and ON/OFF ratios of ~106, demonstrating a 100×  improvement compared to previously reported BEOL compatible TMDs.

This paper summarizes the latest progress in the ITER blanket system design as it proceeds through its final design phase with the Final Design Review planned for Spring 2013. The blanket design is constrained by demanding and sometime conflicting design and interface requirements from the plasma and systems such as the vacuum vessel, in-vessel coils and blanket manifolds. This represents a major design challenge, which is highlighted in this paper with examples of design solutions to accommodate some of the key interface and integration requirements.

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