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Seeded emulsion polymerization is a powerful universal method to produce ultrasmall multifunctional magnetic nanohybrids. In a two-step procedure, iron oxide nanocrystals were initially encapsulated in a polystyrene (PS) shell and subsequently used as beads for a controlled assembly of elongated quantum dots/quantum rods (QDQRs). The synthesis of a continuous PS shell allows the whole construct to be fixed and the composition of the nanohybrid to be tuned. The fluorescence of the QDQRs and magnetism of iron oxide were perfectly preserved, as confirmed by single-particle investigation, fluorescence decay measurements, and relaxometry. Bio-functionalization of the hybrids was straightforward, involving copolymerization of appropriate affinity ligands as shown by immunoblot analysis. Additionally, the universality of this method was shown by the embedment of a broad scale of NPs.

Matching unlikely pairs: In a two-step procedure, iron oxide nanocrystals were initially encapsulated in a polystyrene (PS) shell and subsequently used as beads for a controlled assembly of elongated quantum dots/quantum rods (QDQRs) The fluorescence of the QDQRs and magnetism of iron oxide were perfectly preserved in the resulting nanohybrids.

Various combinations of interlayer shear modes emerge in few-layer molybdenum diselenide grown by chemical vapor deposition depending on the stacking configuration of the sample. Raman measurements may also reveal polytypism and stacking faults, as supported by first principles calculations and high-resolution transmission electron microscopy. Thus, Raman spectroscopy is an important tool in probing stacking-dependent properties in few-layer 2D materials.

Inspired by metallic alloys in atomic solids, two distinct metallic nanoparticles are used, considered as “artificial metal atoms,” to engineer ordered binary nanoparticle alloys at the mesoscale, called binary supracrystals. Here, ferromagnetic 7.2 nm Co nanoparticles are used as large “A” site particles, while either ferromagnetic 4.6 nm Co or nonmagnetic 4.0 nm Ag nanoparticles are used as small “B” site particles to fabricate long-range ordered binary supracrystals with a stoichiometry of AB₂ and AB₁₃. The interparticle distances between 7.2 nm Co nanoparticles within the Co/Ag binary supracrystals can be tuned by a control of crystal structure from AB₂ (CoAg₂) to AB₁₃ (CoAg₁₃). A decrease of magnetic coupling between Co nanoparticles is observed as the Co–Co interparticle distance increases. Furthermore, by alloying 7.2 and 4.6 nm Co nanoparticles to form AB₂ (CoCo₂) binary supracrystals, a collective magnetic behavior of these two particle types, due to the dipolar interaction, is evidenced by observing a single peak in the zero-field-cooled magnetization curve. Compared with the CoAg₂ binary supracrystals, a spin orientation effect in sublattice that reduces the dipolar interactions in the supracrystals is uncovered in CoCo₂ binary supracrystals.

3D magnetic binary supracrystals are fabricated, and the magnetic dipolar interactions are found to be controllable by the binary structure and the type of small nanoparticles. The presence of small ferromagnetic nanoparticles can lead to a weaker dipolar interaction than the insertion of nonmagnetic ones.

Organic–inorganic metal halide perovskite solar cells have emerged in the past few years to promise highly efficient photovoltaic devices at low costs. Here, temperature-sensitive core–shell Ag@TiO₂ nanoparticles are successfully incorporated into perovskite solar cells through a low-temperature processing route, boosting the measured device efficiencies up to 16.3%. Experimental evidence is shown and a theoretical model is developed which predicts that the presence of highly polarizable nanoparticles enhances the radiative decay of excitons and increases the reabsorption of emitted radiation, representing a novel photon recycling scheme. The work elucidates the complicated subtle interactions between light and matter in plasmonic photovoltaic composites. Photonic and plasmonic schemes such as this may help to move highly efficient perovskite solar cells closer to the theoretical limiting efficiencies.

Adding plasmonic core–shell nanoparticles (Ag@TiO₂) to perovskite solar cells is shown to improve the photo­current and thus the overall efficiency. A theoretical model, introducing a novel photon recycling scheme, predicts that highly polarizable nanoparticles act as antennas for light re-emitted from radiative recombination. The work elucidates the complicated, subtle interactions between light and matter in plasmonic photovoltaic composites.

A model of doping confined in atomic layers is proposed for atomic-level insights into the effect of doping on photocatalysis. Co doping confined in three atomic layers of In₂S₃ was implemented with a lamellar hybrid intermediate strategy. Density functional calculations reveal that the introduction of Co ions brings about several new energy levels and increased density of states at the conduction band minimum, leading to sharply increased visible-light absorption and three times higher carrier concentration. Ultrafast transient absorption spectroscopy reveals that the electron transfer time of about 1.6 ps from the valence band to newly formed localized states is due to Co doping. The 25-fold increase in average recovery lifetime is believed to be responsible for the increased of electron–hole separation. The synthesized Co-doped In₂S₃ (three atomic layers) yield a photocurrent of 1.17 mA cm⁻² at 1.5 V vs. RHE, nearly 10 and 17 times higher than that of the perfect In₂S₃ (three atomic layers) and the bulk counterpart, respectively.

Cobalt doping confined in three atomic layers of In₂S₃ is implemented by a lamellar hybrid intermediate strategy. Ultrafast transient absorption spectroscopy shows that the ultrashort electron transfer time (ca. 1.6 ps) from the valence band to newly formed localized states is due to Co doping.

Ion exchange reactions of colloidal nanocrystals provide access to complex products that are synthetically challenging using traditional hot-injection methods. However, such reactions typically achieve only partial material transformations by employing either cation or anion exchange processes. It is now shown that anion and cation exchange reactions can be coupled together and applied sequentially in one integrated pathway that leads to complete material transformations of nanocrystal templates. Although the product nanocrystals do not contain any of the original constituent elements, the original morphology is retained, thereby fully decoupling morphology and composition control. The sequential anion/cation exchange process was applied to pseudo-spherical CdO nanocrystals and ZnO tetrapods, producing fully transformed and shape-controlled nanocrystals of copper and silver sulfides and selenides. Furthermore, hollow core–shell tetrapod ZnS@CdS heterostructures were readily accessible.

Complete transformation: Metal oxide nanocrystals can be transformed into chalcogenides of different metals using sequential anion and cation exchange reactions. The products retain the morphology of the starting material, but contain entirely different elemental components. Morphology and composition control in colloidal nanocrystal synthesis are thus fully decoupled.

Controlled stacking of different two-dimensional (2D) atomic layers will greatly expand the family of 2D materials and broaden their applications. A novel approach for synthesizing MoS₂/WS₂ heterostructures by chemical vapor deposition has been developed. The successful synthesis of pristine MoS₂/WS₂ heterostructures is attributed to using core–shell WO_3−x/MoO_3−x nanowires as a precursor, which naturally ensures the sequential growth of MoS₂ and WS₂. The obtained heterostructures exhibited high crystallinity, strong interlayer interaction, and high mobility, suggesting their promising applications in nanoelectronics. The stacking orientations of the two layers were also explored from both experimental and theoretical aspects. It is elucidated that the rational design of precursors can accurately control the growth of high-quality 2D heterostructures. Moreover, this simple approach opens up a new way for creating various novel 2D heterostructures by using a large variety of heteronanomaterials as precursors.

2D MoS₂/WS₂ heterostructures were successfully grown by using core–shell WO_3−x/MoO_3−x nanowires as a precursor in a CVD process. This method opens up a new way to synthesize various functional 2D heterostructures for novel electronic and optoelectronic devices.

A facile approach to bimetallic phosphides, Co-Fe-P, by a high-temperature (300 °C) reaction between Co-Fe-O nanoparticles and trioctylphosphine is presented. The growth of Co-Fe-P from the Co-Fe-O is anisotropic. As a result, Co-Fe-P nanorods (from the polyhedral Co-Fe-O nanoparticles) and sea-urchin-like Co-Fe-P (from the cubic Co-Fe-O nanoparticles) are synthesized with both the nanorod and the sea-urchin-arm dimensions controlled by Co/Fe ratios. The Co-Fe-P structure, especially the sea-urchin-like (Co_0.54Fe_0.46)₂P, shows enhanced catalysis for the oxygen evolution reaction in KOH with its catalytic efficiency surpassing the commercial Ir catalyst. Our synthesis is simple and may be readily extended to the preparation of other multimetallic phosphides for important catalysis and energy storage applications.

Anisotropic bimetallic Co-Fe-P: Anisotropic Co-Fe-P nanorods and sea urchins were synthesized by controlled phosphidation of Co-Fe-O nanoparticles of polyhedral and cubic shapes, respectively. The Co-Fe-P showed greatly enhanced catalysis for the oxygen evolution reaction. The synthesis may be generalized to prepare metallic phosphides/phosphates for catalysis and energy storage applications.

A first-order phase transition in a bulk material is generally considered to arise at extended defects such as grain boundaries or dislocations, where the energetic barrier between the two phases is reduced. Downsizing a crystal to the nanoscale can exclude the number of defects, leading to enhanced kinetic stabilization of the metastable phase. Here, the disappearance of the first-order metal–insulator transition in defect-free V₂O₃ nanocrystals and the revival of the transition by introducing a certain Cr or Ti impurity content are investigated. The hysteresis width of the transition corresponding to the barrier height decreases with the impurity content. It is proposed that homogeneous impurity doping is a universal method that can control the occurrence of a first-order phase transition in nanoscale materials.

Nanoscale first-order phase transition (metal–insulator transition, antiferromagnetic transition, and structural phase transition) is successfully observed in highly crystalline V₂O₃ nanocrystals doped with Cr or Ti impurities of more than a certain amount. This observation shows that impurity doping is an efficient method to cause the phase transition that was originally suppressed in high-quality nanoscale materials.

n-ZnO nanofilm/p-Si micropillar heterostructure light-emitting diode (LED) arrays for white light emissions are achieved and the light emission intensity of LED array is enhanced by 120% under −0.05% compressive strains. These results indicate a promising approach to fabricate Si-based light-emitting components with high performances enhanced by the piezo-phototronic effect, with potential applications in touchpad technology, personalized signatures, smart skin, and silicon-based photonic integrated circuits.

Combining different therapeutic strategies to treat cancer by overcoming limitations of conventional cancer therapies has shown great promise in both fundamental and clinical studies. Herein, by adding ¹³¹I when making iodine-doped CuS nanoparticles, CuS/[¹³¹I]I nanoparticles are obtained, which after functionalization with polyethylene glycol (PEG) are used for radiotherapy (RT) and photothermal therapy (PTT), by utilizing their intrinsic high near-infrared absorbance and the doped ¹³¹I-radioactivity, respectively. The combined RT and PTT based on CuS/[¹³¹I]I-PEG is then conducted, achieving remarkable synergistic therapeutic effects as demonstrated in the treatment of subcutaneous tumors. In the meanwhile, as revealed by bimodal nuclear imaging and computed tomography (CT) imaging, it is found that CuS/[¹³¹I]I-PEG nanoparticles after being injected into primary solid tumors could migrate to and retain in their nearby sentinel lymph nodes. Importantly, the combined RT and PTT applied on those lymph nodes to assist surgical resection of primary tumors results in remarkably inhibited cancer metastasis and greatly prolonged animal survival. In vivo toxicology studies further reveal that our CuS/I-PEG is not obviously toxic to animals at fourfold of the treatment dose. This work thus demonstrates the potential of combining RT and PTT using a single nanoagent for imaging-guided treatment of metastatic tumors.

Radionuclide iodine-131-doped CuS/I nanoparticles are developed for imaging guided combined photothermal and radiotherapy. Such a treatment strategy not only offers synergistic therapeutic effect in the treatment of subcutaneous tumors, but also enables effective treatment of sentinel lymph nodes under the guidance of multimodal gamma and CT imaging to prevent tumor metastasis.

Electrohydrodynamic-inkjet-printed high-resolution complex 3D structures with multiple functional inks are demonstrated. Printed 3D structures can have a variety of fine patterns, such as vertical or helix-shaped pillars and straight or rounded walls, with high aspect ratios (greater than ≈50) and narrow diameters (≈0.7 μm). Furthermore, the formation of freestanding, bridge-like Ag wire structures on plastic substrates suggests substantial potentials as high-precision, flexible 3D interconnects.

Nanostructured oxide arrays have received significant attention as charge injection and collection electrodes in numerous optoelectronic devices. Zinc oxide (ZnO) nanorods have received particular interest owing to the ease of fabrication using scalable, solution processes with a high degree of control of rod dimension and density. Here, vertical ZnO nanorods as electron injection layers in organic light emitting diodes are implemented for display and lighting purposes. Implementing nanorods into devices with an emissive polymer, poly(9,9-dioctyluorene-alt-benzothiadiazole) (F8BT) and poly(9,9-di-n-octylfluorene-alt-N-(4-butylphenyl)dipheny-lamine) (TFB) as an electron blocking layer, brightness and efficiencies up to 8602 cd m⁻² and 1.66 cd A⁻¹ are achieved. Simple solution processing methodologies combined with postdeposition thermal processing are highlighted to achieve complete wetting of the nanorod arrays with the emissive polymer. The introduction of TFB to minimize charge leakage and nonradiative exciton decay results in dramatic increases to device yields and provides an insight into the operating mechanism of these devices. It is demonstrated that the detected emission originates from within the polymer layers with no evidence of ZnO band edge or defect emission. The work represents a significant development for the ongoing implementation of ZnO nanorod arrays into efficient light emitting devices.

Hybrid LEDs combining vertically aligned ZnO nanorods as electron injection layers and polymeric emitters are demonstrated using a simple solution-processing route. Performance enhancements are achieved by combining a thermal anneal with the inclusion of an electron-blocking polymer. The measured brightness and efficiencies, up to 8600 cd m⁻² and 1.66 cd A⁻¹, highlight the applicability of such architectures for general lighting applications.