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A one-pot strategy has been developed for the preparation of a wide range of transparent-conducting-oxide nanocrystal inks. In their Communication on page 462 ff., H. B. Zeng et al. show that high-performance nanocrystals with high crystallinity, uniform morphology, monodispersity, and high stability are thus obtained. The nanocrystals can also be used for the assembly of high-quality electrodes for optoelectronic devices.

Exploration of low-cost and earth-abundant photocatalysts for highly efficient solar photocatalytic water splitting is of great importance. Although transition-metal dichalcogenides (TMDs) showed outstanding performance as co-catalysts for the hydrogen evolution reaction (HER), designing TMD-hybridized photocatalysts with abundant active sites for the HER still remains challenge. Here, a facile one-pot wet-chemical method is developed to prepare MS₂–CdS (M=W or Mo) nanohybrids. Surprisedly, in the obtained nanohybrids, single-layer MS₂ nanosheets with lateral size of 4–10 nm selectively grow on the Cd-rich (0001) surface of wurtzite CdS nanocrystals. These MS₂–CdS nanohybrids possess a large number of edge sites in the MS₂ layers, which are active sites for the HER. The photocatalytic performances of WS₂–CdS and MoS₂–CdS nanohybrids towards the HER under visible light irradiation (>420 nm) are about 16 and 12 times that of pure CdS, respectively. Importantly, the MS₂–CdS nanohybrids showed enhanced stability after a long-time test (16 h), and 70 % of catalytic activity still remained.

A single layer makes the difference: MS₂–CdS (M=W or Mo) nanohybrids with single-layer MS₂ nanosheets selectively grown on the Cd-rich (0001) surface of wurtzite CdS nanocrystals (see picture) are synthesized by a facile one-pot wet-chemical method. The MS₂–CdS nanohybrids showed excellent photocatalytic activity towards the hydrogen evolution reaction and good stability.

Gallium selenide, an important second-order nonlinear semiconductor, has received much scientific interest. However, the nonlinear properties in its two-dimensional (2D) form are still unknown. A strong second harmonic generation (SHG) in bilayer and multilayer GaSe sheets is reported. This is also the first observation of SHG on 2D GaSe thin layers. The SHG of multilayer GaSe above five layers shows a quadratic dependence on the thickness; while that of a sheet thinner than five layers shows a cubic dependence. The discrepancy between the two SHG responses is attributed to the weakened stability of non-centrosymmetric GaSe in the atomically thin flakes where a layer–layer stacking order tends to favor centrosymmetric modification. Importantly, two-photon excited fluorescence has also been observed in the GaSe sheets. Our free-energy calculations based on first-principles methods support the observed nonlinear optical phenomena of the atomically thin layers.

2D materials: Layer-dependent second-order optical nonlinearity has been observed in few-layer (L) gallium selenide sheets, which is the first observation of second harmonic generation (SHG; see picture) on two-dimensional GaSe nanosheets because of the absence of the inversion symmetric center for ε-GaSe. Two-photon excited fluorescence has also been found in the few-layer GaSe sheets.

A hybrid phototransistor consisting of colloidal PbS quantum dots and few layers of MoS₂ (≥2 layers) is demonstrated. The hybrid benefits from tailored light absorption in the quantum dots throughout the visible/near infrared region, efficient charge-carrier separation at the p–n interface, and fast carrier transport through the MoS₂ channel. It shows responsivity of up to 10⁶ A W^–1 and backgate-dependent sensitivity.

Inserting polymers into a crystalline inorganic matrix to understand the structure, position, and the structure–property relationships of the resulting composites is important for designing new inorganic-organic materials and tuning their properties. Single crystals of polymer-chalcogenide composites were successfully prepared by trapping polyethyleneglycol within a selenidostannate matrix under surfactant-thermal conditions. This work might provide a new strategy for preparing novel crystalline polymer-inorganic composites through encapsulating polymer chains within inorganic matrices.

Common thread: Inserting a polymer into a crystalline inorganic matrix to understand its structure, position, and the structure–property relationships of the resulting composites is important for designing new inorganic–organic materials and tuning their properties. Single crystals of polymer-chalcogenide composites were isolated by trapping polyethyleneglycol within a selenidostannate matrix under surfactant-thermal conditions.

3D printing of reduced graphene oxide (rGO) nanowires is realized at room temperature by local growth of GO at the meniscus formed at a micropipette tip followed by reduction of GO by thermal or chemical treatment. 3D rGO nanowires with diverse and complicated forms are successfully printed, demonstrating their ability to grow in any direction and at the selected sites.

Chalcogenide nanostructures and nanocomposites have been the focus of semiconductor nanomaterial research due to their remarkable optoelectronic and photocatalytic properties and potential application in photodegrading enviromental pollutions. However, currently available synthesizing methods tend to be costly and inefficient. In this paper, we propose a facile two-step solution-phase method to synthesize well-defined monodisperse ZnS–CdS nanocomposites. The morphology and size of ZnS nanoparticles can be easily controlled by adjusting the amount of the source of sulfur. After surface modification with tiny CdS nanoparticles through natural electrostatic attraction, uniform ZnS–CdS nanocomposites are obtained, which has been further confirmed by transmission electron microscopy (TEM) and energy dispersive spectrometry (EDS). The photocatalytic activities of various ZnS samples and ZnS–CdS nanocomposites have been investigated by degrading Rhodamine B under UV-light. Compared with pure ZnS nanoparticles and ZnS powders, the as-obtained ZnS–CdS nanocomposites exhibit excellent photocatalytic performances due to the effective charge separation and increased specific surface area by the attachment of CdS. Moreover, resulting from the effective passivation of surface electronic states, the photoluminescence intensity of the ZnS–CdS nanocomposites is also significantly improved relative to plain ZnS.

Chalcogenide nanostructure has attracted world-wide attention due to the great potential of applications in photocatalysis and optoelectronics. Well-defined heterostructures, which often exhibit superior properties, are of extreme importance. In this paper, a facile method to synthesize monodisperse ZnS nanoparticles (NPs) and ZnS–CdS nanocomposites (NCs) is proposed. The ZnS–CdS heterostructure not only shows obvious advantage in photoactivities, but also offers exciting opportunities for the development of new dual-semiconductor nanostructures.

CdSe/Zn_1-XCd_XS core/shell heterostructured quantum dots (QDs) with varying shell thicknesses are studied as the active material in a series of electroluminescent devices. “Giant” CdSe/Zn_1-XCd_XS QDs (e.g., CdSe core radius of 2 nm and Zn_1-XCd_XS shell thickness of 6.3 nm) demonstrate a high device efficiency (peak EQE = 7.4%) and a record-high brightness (>100 000 cd m⁻²) of deep-red emission, along with improved device stability.

A 1D–2D hybrid complementary logic inverter comprising of ZnO nanowire and WSe₂ nanosheet field-effect transistors (FETs) is fabricated on glass, which shows excellent static and dynamic electrical performances with a voltage gain of ≈60, sub-nanowatt power consumption, and at least 1 kHz inverting speed.

Colloidosomes are microcapsules consisting of nanoparticle shells. These microcarriers can be self-assembled from a wide range of colloidal particles with selective chemical, physical, and morphological properties and show promise for application in the field of theranostic nanomedicine. Previous studies have mainly focused on fairly large colloidosomes (>1 μm) based on a single kind of particle; however, the intrinsic building-block nature of this microcarrier has not been exploited so far for the introduction of tailored functionality at the nanoscale. We report a synthetic route based on interfacial shear rheology studies that allows the simultaneous incorporation of different nanoparticles with distinct physical properties, that is, superparamagnetic iron oxide and fluorescent silica nanoparticles, in a single submicron colloidosome. These tailor-made microcapsules can potentially be used in various biomedical applications, including magnetic hyperthermia, magnetic particle imaging, drug targeting, and bioimaging.

Outwardly functional but empty inside: Bifunctional submicron colloidosomes (see picture) were coassembled from superparamagnetic iron oxide nanoparticles (SPIONs) and fluorescent-dye-doped silica nanoparticles (FSNPs) at the interface between water-in-oil-emulsion droplets and then transferred by centrifugation to a fresh aqueous phase. These inherently rigid microcapsules feature a nanoporous shell and an aqueous core for active-agent encapsulation.