Aggregation of amyloid-β peptides (Aβ) into fibrils is the key pathological feature of many neurodegenerative disorders. Typical drugs inhibit Aβ fibrillation by binding to monomers in 1:1 ratio and display low efficacy. Here, we report that model CdTe nanoparticles (NPs) can efficiently prevent fibrillation of Aβ associating with 100–330 monomers at once. The inhibition is based on the binding multiple Aβ oligomers rather than individual monomers. The oligomer route of inhibition is associated with strong van der Waals interactions characteristic for NPs and presents substantial advantages in the mitigation of toxicity of the misfolded peptides. Molar efficiency and the inhibition mechanism revealed by NPs are analogous to those found for proteins responsible for prevention of amyloid fibrillation in human body. Besides providing a stimulus for finding biocompatible NPs with similar capabilities, these data suggest that inorganic NPs can mimic some sophisticated biological functionalities of proteins.

Use of the chemical effects of ultrasound has made sonochemistry a topic of intensive investigation as a promising route for the fabrication of various nanostructured materials in colloidal systems. [1][2][3][4][5][6][7][8] Although this technique provides a very quick, simple, and cost-effective route to nanostructures under ambient conditions, there have not been any reports regarding either the in situ synthesis or on-substrate growth of aligned one-dimensional (1D) nanostructured materials. Direct synthesis of aligned nanostructured materials on a substrate is highly desirable and the way forward for many electronic applications, such as electron emitters, [9] nanolasers, [10] and field-effect transistors. [11] This inspired us to extend our sonochemical method of making colloidal suspensions of randomly oriented, 1D nanocarbon materials [6] to on-substrate growth of aligned nanostructured materials. Taking ZnO as a target material, we show here that highly crystalline 1D nanostructures can be vertically grown on various substrates over large areas using sonochemical methods. Vertically aligned 1D ZnO nanostructured materials have attracted a great deal of attention with regard to nanoelectronic applications, such as electrodes for solar cells, [12] lasers, [10] field emitters, [13] and so on. Conventional approaches to synthesizing well-aligned 1D ZnO nanostructured materials have been based on vapor-phase reactions [10,14,15] or hydrothermal reactions. [16][17][18] While vapor-phase synthesis methods can produce highly crystalline 1D ZnO nanostructured materials, they require severe environmental conditions, such as high temperature (up to 1400°C) and low pressure, and a complicated vacuum and heating system. In addition, such high temperatures are not suitable for nanoelectronic circuit integration. Unlike the vapor-phase synthesis method, the hydrothermal synthesis method can produce 1D ZnO nanostructured materials at low temperature (below 200°C) under higher pressure. The reaction time required for the growth of 1D ZnO nanostructured materials, however, is too long (usually from several hours to several days). Recently, Hu et al. reported a quick sonochemical route to ZnO nanorods. [19] However, the possibility of on-substrate growth of aligned ZnO nanorods was not investigated. Therefore, a simple and fast route for the synthesis of wellaligned 1D ZnO nanostructured materials on the substrate under ambient conditions has remained a great challenge until now. In this paper, we present a simple sonochemical route for the synthesis of vertically aligned ZnO nanorods on various substrates. Figure 1a shows schematically a sonochemical route to vertically aligned ZnO nanorod arrays on various substrates. The ZnO nanorod arrays were fabricated on a large-area Zn sheet (4 cm × 4 cm), as shown in Figure 1b. Figure 1c and d show field-emission scanning electron microscopy (FESEM) images of ZnO nanorod arrays grown on a Zn sheet. By SEM obser- COMMUNICATION

Batch growth of high-mobility (μFE > 10 cm2V–1s–1) molybdenum disulfide (MoS2) films can be achieved by means of the chemical vapor deposition (CVD) method at high temperatures (>500 °C) on rigid substrates. Although high-temperature growth guarantees film quality, time- and cost-consuming transfer processes are required to fabricate flexible devices. In contrast, low-temperature approaches (<250 °C) for direct growth on polymer substrates have thus far achieved film growth with limited spatial homogeneity and electrical performance (μFE is unreported). The growth of a high-mobility MoS2 film directly on a polymer substrate remains challenging. In this study, a novel low-temperature (250 °C) process to successfully overcome this challenge by kinetics-controlled metal–organic CVD (MOCVD) is proposed. Low-temperature MOCVD was achieved by maintaining the flux of an alkali-metal catalyst constant during the process; furthermore, MoS2 was directly synthesized on a polyimide (PI) substrate. The as-grown film exhibits a 4 in. wafer-scale uniformity, field-effect mobility of 10 cm2V–1s–1, and on/off ratio of 105, which are comparable with those of high-temperature-grown MoS2. The directly fabricated flexible MoS2 field-effect transistors demonstrate excellent stability of electrical properties following a 1000 cycle bending test with a 1 mm radius.

Phase transition and coexistence of 2H (trigonal prismatic structure) and 1T′ (distorted octahedral structure) phases occur easily in molybdenum ditelluride (MoTe 2 ) when compared with other 2D MX 2 type (M = Mo, W and X = S, Se) transition metal dichalcogenides (TMDs) because of small discrepancies in the cohesive energy. [1][2][3][4] Phase-engineered 2D TMDs, particularly MoTe 2 films including 2H, 1T′, and 1T phases, are very attractive candidates for numerous electronic applications, such as ambipolar field-effect transistors (FETs), environmental sensors, superconductors, spintronics, and valley optoelectronics. [5][6][7][8] Atomically thin-layer 2H MoTe 2 possesses a narrow bandgap energy of 1 eV in comparison to the bandgap energy (1.89 eV) of monolayer MoS 2 and is a potential candidate for various optoelectronic device applications, such as solar cells and photodetectors. [3,8,9] From the electronic device application point of view, the 2H and the 1T phases, i.e., semiconducting and semimetal MoTe 2 are applicable as a 2D materials beyond molybdenum disulfide such as molybdenum ditelluride (MoTe 2 ) have attracted increasing attention because of their distinctive properties, such as phase-engineered, relatively narrow direct bandgap of 1.0-1.1 eV and superior carrier transport. However, a wafer-scale synthesis process is required for achieving practical applications in next-generation electronic devices using MoTe 2 thin films. Herein, the direct growth of atomically thin 1T′, 1T′-2H mixed, and 2H phases MoTe 2 films on a 4 in. SiO 2 /Si wafer with high spatial uniformity (≈96%) via metal-organic vapor phase deposition is reported. Furthermore, the wafer-scale phase engineering of few-layer MoTe 2 film is investigated by controlling the H 2 molar flow rate. While the use of a low H 2 molar flow rate results in 1T′ and 1T′-2H mixed phase MoTe 2 films, 2H phase MoTe 2 films are obtained at a high H 2 molar flow rate. Field-effect transistors fabricated with the prepared 2H and 1T′ phases MoTe 2 channels reveal p-type semiconductor and semimetal properties, respectively. This

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