Two-dimensional materials such as graphene and transition metal dichalcogenides (TMDs) are ideal candidates to create ultra-thin electronics suitable for flexible substrates. Although optoelectronic devices based on TMDs have demonstrated remarkable performance, scalability is still a significant issue. Most devices are created using techniques that are not suitable for mass production, such as mechanical exfoliation of monolayer flakes and patterning by electron-beam lithography. Here we show that large-area MoS grown by chemical vapor deposition and patterned by photolithography yields highly sensitive photodetectors, with record shot-noise-limited detectivities of 8.7 × 10 Jones in ambient condition and even higher when sealed with a protective layer. These detectivity values are higher than the highest values reported for photodetectors based on exfoliated MoS. We study MoS devices with gold electrodes and graphene electrodes. The devices with graphene electrodes have a tunable band alignment and are especially attractive for scalable ultra-thin flexible optoelectronics.

Amyloid β (Aβ) peptide plays a major role in Alzheimer's disease (AD) and occurs in multiple forms, including pyroglutamylated Aβ (AβpE). Identification and characterization of the most cytotoxic Aβ species is necessary for advancement in AD diagnostics and therapeutics. While in brain tissue multiple Aβ species act in combination, structure/toxicity studies and immunotherapy trials have been focused on individual forms of Aβ. As a result, the molecular composition and the structural features of "toxic Aβ oligomers" have remained unresolved. Here, we have used a novel approach, hydration from gas phase coupled with isotope-edited Fourier transform infrared (FTIR) spectroscopy, to identify the prefibrillar assemblies formed by Aβ and AβpE and to resolve the structures of both peptides in combination. The peptides form unusual β-sheet oligomers stabilized by intramolecular H-bonding as opposed to intermolecular H-bonding in the fibrils. Time-dependent morphological changes in peptide assemblies have been visualized by atomic force microscopy. Aβ/AβpE hetero-oligomers exert unsurpassed cytotoxic effect on PC12 cells as compared to oligomers of individual peptides or fibrils. These findings lead to a novel concept that Aβ/AβpE hetero-oligomers, not just Aβ or AβpE oligomers, constitute the main neurotoxic conformation. The hetero-oligomers thus present a new biomarker that may be targeted for development of more efficient diagnostic and immunotherapeutic strategies to combat AD.

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Two novel quadruple hydrogen-bonded supramolecular structure 1:2 adducts of dimethylglyoxime·benzoic acid and dimethylglyoxime·cinnamic acid have been designed and optimized at the B3LYP/6-31G* level. The calculated results show that, at a temperature of 298.15 K and pressure of 0.1 MPa, the changes in the Gibbs free energy (ΔG T ) for the two aggregations from monomers to corresponding trimers are −41.7 and −42.7 kJ/mol, respectively, which imply that the processes of forming the trimers are spontaneous. Based on this design, we have synthesized the anticipatory supramolecular compounds successfully by selecting catalysts, and their crystal structures closely resemble the optimized structures. The predicted vibrational frequencies are in good agreement with the experimental values. Thermal stability analyses demonstrate that these two supramolecular compounds are new complexes and they are not the ordinary superposition of the original monomers.