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Liquid metal for high-entropy alloy nanoparticles synthesis
2023
High-entropy alloy nanoparticles (HEA-NPs) show great potential as functional materials
1
–
3
. However, thus far, the realized high-entropy alloys have been restricted to palettes of similar elements, which greatly hinders the material design, property optimization and mechanistic exploration for different applications
4
,
5
. Herein, we discovered that liquid metal endowing negative mixing enthalpy with other elements could provide a stable thermodynamic condition and act as a desirable dynamic mixing reservoir, thus realizing the synthesis of HEA-NPs with a diverse range of metal elements in mild reaction conditions. The involved elements have a wide range of atomic radii (1.24–1.97 Å) and melting points (303–3,683 K). We also realized the precisely fabricated structures of nanoparticles via mixing enthalpy tuning. Moreover, the real-time conversion process (that is, from liquid metal to crystalline HEA-NPs) is captured in situ, which confirmed a dynamic fission–fusion behaviour during the alloying process.
We discovered that liquid metal endowing negative mixing enthalpy with other elements could provide a stable thermodynamic condition and act as a desirable dynamic mixing reservoir, realizing the synthesis of high-entropy alloy nanoparticles.
Journal Article
A top-down strategy for amorphization of hydroxyl compounds for electrocatalytic oxygen evolution
2022
Amorphous materials have attracted increasing attention in diverse fields due to their unique properties, yet their controllable fabrications still remain great challenges. Here, we demonstrate a top-down strategy for the fabrications of amorphous oxides through the amorphization of hydroxides. The versatility of this strategy has been validated by the amorphizations of unitary, binary and ternary hydroxides. Detailed characterizations indicate that the amorphization process is realized by the variation of coordination environment during thermal treatment, where the M–OH octahedral structure in hydroxides evolves to M–O tetrahedral structure in amorphous oxides with the disappearance of the M–M coordination. The optimal amorphous oxide (FeCoSn(OH)
6
-300) exhibits superior oxygen evolution reaction (OER) activity in alkaline media, where the turnover frequency (TOF) value is 39.4 times higher than that of FeCoSn(OH)
6
. Moreover, the enhanced OER performance and the amorphization process are investigated with density functional theory (DFT) and molecule dynamics (MD) simulations. The reported top-down fabrication strategy for fabricating amorphous oxides, may further promote fundamental research into and practical applications of amorphous materials for catalysis.
A versatile top-down strategy has been shown to produce amorphous oxides through amorphization of corresponding hydroxides. This approach was used to generate various unitary, binary and ternary amorphous oxides for electrocatalytic oxygen evolution.
Journal Article
Comprehensive defect suppression in perovskite nanocrystals for high-efficiency light-emitting diodes
2021
Electroluminescence efficiencies of metal halide perovskite nanocrystals (PNCs) are limited by a lack of material strategies that can both suppress the formation of defects and enhance the charge carrier confinement. Here we report a one-dopant alloying strategy that generates smaller, monodisperse colloidal particles (confining electrons and holes, and boosting radiative recombination) with fewer surface defects (reducing non-radiative recombination). Doping of guanidinium into formamidinium lead bromide PNCs yields limited bulk solubility while creating an entropy-stabilized phase in the PNCs and leading to smaller PNCs with more carrier confinement. The extra guanidinium segregates to the surface and stabilizes the undercoordinated sites. Furthermore, a surface-stabilizing 1,3,5-tris(bromomethyl)-2,4,6-triethylbenzene was applied as a bromide vacancy healing agent. The result is highly efficient PNC-based light-emitting diodes that have current efficiency of 108 cd A−1 (external quantum efficiency of 23.4%), which rises to 205 cd A−1 (external quantum efficiency of 45.5%) with a hemispherical lens.Guanidinium doping is shown to enhance the operation of perovskite nanocrystal light-emitting diodes.
Journal Article
Ultra-durable superhydrophobic cellular coatings
2023
Developing versatile, scalable, and durable coatings that resist the accretion of matters (liquid, vapor, and solid phases) in various operating environments is important to industrial applications, yet has proven challenging. Here, we report a cellular coating that imparts liquid-repellence, vapor-imperviousness, and solid-shedding capabilities without the need for complicated structures and fabrication processes. The key lies in designing basic cells consisting of rigid microshells and releasable nanoseeds, which together serve as a rigid shield and a bridge that chemically bonds with matrix and substrate. The durability and strong resistance to accretion of different matters of our cellular coating are evidenced by strong anti-abrasion, enhanced anti-corrosion against saltwater over 1000 h, and maintaining dry in complicated phase change conditions. The cells can be impregnated into diverse matrixes for facile mass production through scalable spraying. Our strategy provides a generic design blueprint for engineering ultra-durable coatings for a wide range of applications.
The design and scalable fabrication of durable superhydrophobic coatings that prevent accretion of matter is challenging. Here the authors developed a generic cellular design for ultra-durable coatings that provides liquid-repellence, vapor imperviousness, and solid-shedding capabilities.
Journal Article
Ultralong lifetime and efficient room temperature phosphorescent carbon dots through multi-confinement structure design
2020
Room temperature phosphorescence materials have inspired extensive attention owing to their great potential in optical applications. However, it is hard to achieve a room temperature phosphorescence material with simultaneous long lifetime and high phosphorescence quantum efficiency. Herein, multi-confined carbon dots were designed and fabricated, enabling room temperature phosphorescence material with simultaneous ultralong lifetime, high phosphorescence quantum efficiency, and excellent stability. The multi-confinement by a highly rigid network, stable covalent bonding, and 3D spatial restriction efficiently rigidified the triplet excited states of carbon dots from non-radiative deactivation. The as-designed multi-confined carbon dots exhibit ultralong lifetime of 5.72 s, phosphorescence quantum efficiency of 26.36%, and exceptional stability against strong oxidants, acids and bases, as well as polar solvents. This work provides design principles and a universal strategy to construct metal-free room temperature phosphorescence materials with ultralong lifetime, high phosphorescence quantum efficiency, and high stability for promising applications, especially under harsh conditions.
For room temperature phosphorescence (RTP) materials to reach their potential for optical applications, new materials with improved performance must be realized. Here, the authors report multi-confined carbon dots as high stability RTP materials with long afterglow lifetime & high efficiency.
Journal Article
Defect engineering of layered double hydroxide nanosheets as inorganic photosensitizers for NIR-III photodynamic cancer therapy
2022
Although two-dimensional (2D) layered double hydroxides (LDHs) have been widely used as efficient nanoagents for biological diagnosis and treatment, they have been found to be inert as photosensitizers (PSs) for photodynamic therapy (PDT). Herein, we report the defect engineering of ultrathin 2D CoMo-LDH and NiMo-LDH nanosheets as highly active inorganic PSs for PDT in the third near-infrared (NIR-III) window. Hydrothermal-synthesized 2D CoMo-LDH and NiMo-LDH nanosheets are etched via a simple acid treatment to obtain defect-rich CoMo-LDH and NiMo-LDH nanosheets. Importantly, the defect-rich CoMo-LDH nanosheets exhibit much higher activity (~97 times) for generation of reactive oxygen species than that of the pristine CoMo-LDH nanosheets under a NIR-III 1567 nm laser irradiation. Therefore, after modification with polyethylene glycol, the defect-rich CoMo-LDH nanosheets can be used as an efficient inorganic PS for PDT to efficiently induce cancer cells apoptosis in vitro and eradicate tumors in vivo under 1567 nm laser irradiation.
Defect engineering of 2 dimensional layered double hydroxide sheets improves their photocatalytic activity. Here, the authors etch sheets in acid and show that the etched sheets generate substantially more reactive oxygen species that untreated sheets and the treated sheets can be used to kill cancer cells in vitro and in vivo.
Journal Article
Photothermal therapy with immune-adjuvant nanoparticles together with checkpoint blockade for effective cancer immunotherapy
2016
A therapeutic strategy that can eliminate primary tumours, inhibit metastases, and prevent tumour relapses is developed herein by combining adjuvant nanoparticle-based photothermal therapy with checkpoint-blockade immunotherapy. Indocyanine green (ICG), a photothermal agent, and imiquimod (R837), a Toll-like-receptor-7 agonist, are co-encapsulated by poly(lactic-co-glycolic) acid (PLGA). The formed PLGA-ICG-R837 nanoparticles composed purely by three clinically approved components can be used for near-infrared laser-triggered photothermal ablation of primary tumours, generating tumour-associated antigens, which in the presence of R837-containing nanoparticles as the adjuvant can show vaccine-like functions. In combination with the checkpoint-blockade using anti-cytotoxic T-lymphocyte antigen-4 (CTLA4), the generated immunological responses will be able to attack remaining tumour cells in mice, useful in metastasis inhibition, and may potentially be applicable for various types of tumour models. Furthermore, such strategy offers a strong immunological memory effect, which can provide protection against tumour rechallenging post elimination of their initial tumours.
Photothermal therapy can induce an anti-tumour immune response by producing tumour-associated antigens. Here, the authors design a nanoparticle that simultaneously acts as a photothermal agent and an immune-adjuvant and demonstrate the anti-tumour efficacy in combination with anti-CTLA4 therapy in preclinical murine cancer models.
Journal Article
Overall electrochemical splitting of water at the heterogeneous interface of nickel and iron oxide
2019
Efficient generation of hydrogen from water-splitting is an underpinning chemistry to realize the hydrogen economy. Low cost, transition metals such as nickel and iron-based oxides/hydroxides have been regarded as promising catalysts for the oxygen evolution reaction in alkaline media with overpotentials as low as ~200 mV to achieve 10 mA cm
−2
, however, they are generally unsuitable for the hydrogen evolution reaction. Herein, we show a Janus nanoparticle catalyst with a nickel–iron oxide interface and multi-site functionality for a highly efficient hydrogen evolution reaction with a comparable performance to the benchmark platinum on carbon catalyst. Density functional theory calculations reveal that the hydrogen evolution reaction catalytic activity of the nanoparticle is induced by the strong electronic coupling effect between the iron oxide and the nickel at the interface. Remarkably, the catalyst also exhibits extraordinary oxygen evolution reaction activity, enabling an active and stable bi-functional catalyst for whole cell water-splitting with, to the best of our knowledge, the highest energy efficiency (83.7%) reported to date.
Ni–Fe based compound are known as active electrocatalysts for oxygen evolution reaction, but not a good choice for the other half-reaction of water-splitting. Here the authors report a unique interface between Ni and γ-Fe
2
O
3
that efficiently catalyzes the cathodic hydrogen evolution reaction.
Journal Article
Selective organ targeting (SORT) nanoparticles for tissue-specific mRNA delivery and CRISPR–Cas gene editing
by
Cheng, Qiang
,
Dilliard, Sean A
,
Tuo, Wei
in
Cellular apoptosis susceptibility protein
,
CRISPR
,
Endothelial cells
2020
CRISPR–Cas gene editing and messenger RNA-based protein replacement therapy hold tremendous potential to effectively treat disease-causing mutations with diverse cellular origin. However, it is currently impossible to rationally design nanoparticles that selectively target specific tissues. Here, we report a strategy termed selective organ targeting (SORT) wherein multiple classes of lipid nanoparticles are systematically engineered to exclusively edit extrahepatic tissues via addition of a supplemental SORT molecule. Lung-, spleen- and liver-targeted SORT lipid nanoparticles were designed to selectively edit therapeutically relevant cell types including epithelial cells, endothelial cells, B cells, T cells and hepatocytes. SORT is compatible with multiple gene editing techniques, including mRNA, Cas9 mRNA/single guide RNA and Cas9 ribonucleoprotein complexes, and is envisioned to aid the development of protein replacement and gene correction therapeutics in targeted tissues.The addition of selective organ targeting molecules to nanoparticles allows the specific targeting of extrahepatic tissues, enabling gene editing of distinct cell populations outside the liver.
Journal Article
Size-dependent lanthanide energy transfer amplifies upconversion luminescence quantum yields
2024
Optical upconversion from lanthanide-doped nanoparticles is promising for a variety of applications ranging from bioimaging, optogenetics, nanothermometry, super-resolution nanoscopy and volumetric displays to solar cells. Despite remarkable progress made in enhancing upconversion to fuel these applications, achieving luminescence of upconversion nanoparticles (UCNPs) that is comparable to or higher than the bulk counterparts has been challenging due to nanoscale-induced quenching effects. Here we demonstrate a size-dependent lanthanide energy transfer effect in a conceptual design of hexagonal sodium yttrium fluoride (NaYF
4
) core–shell–shell NaYF
4
@NaYF
4
:Yb/Tm@NaYF
4
UCNPs with depleted surface quenching. We show that precise control over the domain size (or the thickness of the middle shell doped with ytterbium (Yb) and thulium (Tm) from 1.2 to 13 nm) increases the lanthanide energy transfer efficiency (from 30.2 to 50.4%) and amplifies the upconversion quantum yield to a high value of 13.0 ± 1.3% in sub-50 nm UCNPs (excitation: 980 nm, 100 W cm
−2
), which is around fourfold higher than the micrometre-scale hexagonal NaYF
4
:Yb/Tm bulk counterparts. Spectroscopic studies and theoretical microscopic modelling reveal that long-range lanthanide energy transfer (>9.5 nm) takes place and underlies the observed size-dependent phenomena. Demonstration of size-dependent lanthanide energy transfer and upconversion quantum yields at the nanoscale transforms our long-existing conceptual understanding of lanthanide energy transfer (size independence), thereby having important implications for applications of lanthanide nanophotonics and biophotonics.
Researchers demonstrate a size-dependent lanthanide energy transfer effect in upconversion nanoparticles with depleted surface quenching, resulting in upconversion quantum yields of 13.0 ± 1.3%.
Journal Article