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Approaches to achieve stable perovskite nanocrystals (PNCs) of interest, in particular those with large structural anisotropy, through protective coating of the inorganic shell at a single‐nanocrystal (NC) level are comparatively few and limited in scope. Reported here is a robust amphiphilic‐diblock‐copolymer‐enabled strategy for crafting highly‐stable anisotropic CsPbBr3 nanosheets (NSs) by in situ formation of a uniform inorganic shell (1st shielding) that is intimately ligated with hydrophobic polymers (2nd shielding). The dual‐protected NSs display an array of remarkable stabilities (i.e. thermal, photostability, moisture, polar solvent, aliphatic amine, etc.) and find application in white‐light‐emitting diodes. In principle, by anchoring other multidentate amphiphilic polymer ligands on the surface of PNCs, followed by templated‐growth of shell materials of interest, a rich variety of dual‐shelled, multifunctional PNCs with markedly improved stabilities can be created for use in optics, optoelectronics, and sensory devices. [ABSTRACT FROM AUTHOR]

Thermoresponsive nanoparticles (NPs) represent an important hybrid material comprising functional NPs with temperature‐sensitive polymer ligands. Strikingly, significant discrepancies in optical and catalytic properties of thermoresponsive noble‐metal NPs have been reported, and have yet to be unraveled. Reported herein is the crafting of Au NPs, intimately and permanently ligated by thermoresponsive poly(N‐isopropylacrylamide) (PNIPAM), in situ using a starlike block copolymer nanoreactor as model system to resolve the paradox noted above. As temperature rises, plasmonic absorption of PNIPAM‐capped Au NPs red‐shifts with increased intensity in the absence of free linear PNIPAM, whereas a greater red‐shift with decreased intensity occurs in the presence of deliberately introduced linear PNIPAM. Remarkably, the absence or addition of free linear PNIPAM also accounts for non‐monotonic or switchable on/off catalytic performance, respectively, of PNIPAM‐capped Au NPs. [ABSTRACT FROM AUTHOR]

Abstract: Electron field emission, electrons emitted from solid surfaces under high electric field, offers significant scientific interests in materials sciences and potential optoelectronics applications. 2D atomic layers, such as MoS2, exhibit fascinating properties for diverse applications in next‐generation nanodevices and rich physical phenomena for fundamental research. However, the study on field emission of semiconducting monolayers is lacking owing to its low efficiency and stability of electron emission. Here, electron field emission of the geometrically modulated monolayer semiconductors suspended with 1D nanoarrays is demonstrated. Chemical vapor deposition synthesis of two prototype monolayers of transition metal dichalcogenides (TMD), MoS2 and MoSe2, is presented and their diverse band structures offer an ideal platform to explore the fundamental process of the electron emission in the TMD. Geometrical modulation and charge transfer of the semiconducting monolayers can be significantly tuned with the structural suspension with the 1D ZnO nanoarrays. Possible mechanisms on the enhanced electron emission of the 2D monolayers are discussed. With geometrical control of the monolayers, a highly efficient and stable electron emission of TMD monolayers is achieved in low turn‐on electric fields, enabling applications on electrons sources and opening a new avenue toward geometrically tuned atomic layers. [ABSTRACT FROM AUTHOR]

Despite impressive recent advances in the synthesis of lead chalcogenide solid nanoparticles, there are no examples of lead chalcogenide hollow nanoparticles (HNPs) with controlled diameter and shell thickness as current synthetic approaches for HNPs have inherent limitations associated with their complexity, inability to precisely control the dimensions, and limited possibilities with regard to applicable materials. Herein, we report on an unconventional strategy for crafting uniform lead chalcogenide (PbS and PbTe) HNPs with tailorable size, surface chemistry, and near-IR absorption. Amphiphilic star-like triblock copolymers [polystyrene-block-poly(acrylic acid)-block-polystyrene and polystyrene-block-poly(acrylic acid)-block-poly(3,4-ethylenedioxythiophene)] were rationally synthesized and exploited as nanoreactors for the formation of uniform PbS and PbTe HNPs. Compared to their solid counterparts, the near-IR absorption of the HNPs is blue-shifted owing to the hollow interior. This strategy can be readily extended to other types of intriguing low-band-gap HNPs for diverse applications. [ABSTRACT FROM AUTHOR]

The shape of Ag2O crystals that evolve from edge and corner-truncated cubes into rhombicuboctahedrons, then to hexapods can be conducted precisely by simply controlling the amount of AgNO3, NH4NO3 and NaOH precursors. The edge and corner-truncated cube crystals possess the highest photocatalytic activity, followed by the rhombicuboctahedrons, then the hexapods. The photocatalytic activity of the Ag2O crystals depends greatly on the type of the exposed facets. The {1 0 0} facets exhibit the highest photocatalytic activity in methyl orange solution under full-spectrum light irradiation, followed by the {1 1 0} facets, then the {1 1 1} facets. The {1 0 0} facets are also demonstrated to show intense susceptibility toward etching by NH3. [ABSTRACT FROM AUTHOR]

Here, a controlled synthesis of remarkable 3D photocatalysts is presented that is composed of ultrahigh-density unaggregated plasmonic Au nanoparticles (AuNPs) chemically bound to vertically aligned ZnO nanorod arrays (ZNA) through bifunctional molecular linkers. Experimental probes and electromagnetic simulations of electron transfer and localized plasmonic coupling processes are exploited to gain insight into the underlying light-irradiation-induced interactions in the 3D ZNA-AuNPs photocatalysts. Highly dense AuNPs on ZNA surfaces act as sinks for the storage of UV-generated electrons, which promote the separation of charge carriers and create numerous photocatalytic reaction centers. Furthermore, 3D finite-difference time domain simulation indicates that significant visible light confinement and enhancement around the ZNA-AuNPs interfacial plasmon 'hot spots' contribute to efficient conversion of light energy to electron-hole pairs. Significantly, in comparison with the bare ZNA, the 10-nm-sized AuNPs-decorated ZNA exhibits 10.6-fold enhanced photoreaction rate in the entire UV-vis region. Moreover, various novel hybrid structures based on the plasmonic AuNPs and diverse nanostructures (films, powdered nanorods, mesoporous, and nanotubes) or functional materials (multiferroic BiFeO3, CuInGaSe2 absorber layers, and photoactive TiO2) are successfully constructed using the present synthesis methodology. It may stimulate the progress in materials science toward the synthesis of multifunctional plasmonic heterostructures or devices. [ABSTRACT FROM AUTHOR]

Two‐dimensional (2D) nanomaterials are widely recognized as an important class of functional materials possessing superior electrochemical reaction kinetics. Herein, an L‐aspartic acid (AA)‐modified graphene oxide (GO) templating strategy is developed to in situ yield ultrathin (i.e., ≈5 nm) cobalt carbonate hydroxide (Co2(OH)2CO3) nanosheets as advanced anode materials of lithium ion batteries. Notably, the covalent tethering of AA on the GO surface renders a high density of carboxyl groups that impart effective loading of Co‐containing precursors and subsequent growth into Co2(OH)2CO3 nanosheets bridging adjacent GO layers. The lasagna‐like Co2(OH)2CO3‐GO nanocomposites exhibit an ultrahigh lithium storage capacity of 1770 mAh g−1 after 500 cycles at 100 mA g−1. It is noteworthy that the cycled Co2(OH)2CO3 phase separates into homogeneously dispersed Co(OH)2 and CoCO3 phases with two different charge plateaus at ≈1.2 and 2.0 V, respectively, which effectively inhibit large‐scale homophase coarsening of Co, Li2CO3, and LiOH. The much shortened Li+/e− transfer distance enabled by individual ultrathin Co2(OH)2CO3 nanosheet together with robust layer‐by‐layer assembled nanostructure of Co2(OH)2CO3‐GO confers the superior electrochemical reactivity and mechanical stability. As such, the amino acid‐modified GO templating strategy may represent a simple yet robust means of crafting a variety of 2D nanostructured composites of interest for energy storage applications. [ABSTRACT FROM AUTHOR]

Sternförmige Triblockcopolymere, die durch radikalische Atomtransferpolymerisation erhalten wurden, wurden als Nanoreaktoren für die Synthese hohler Halbleiter‐Nanopartikel verwendet, die mit herkömmlichen Verfahren nicht herzustellen sind. In der Zuschrift auf S. 13126 ff. beschreiben Z. Lin et al. die Synthese gleichmäßiger hohler Nanopartikel aus PbS und PbTe nach dieser Strategie. [ABSTRACT FROM AUTHOR]