Local Charge Density Research Articles

Plasmonic Imaging of Single DNA with Charge Sensitive Monolayer WS2.

Imaging the surface charge of biomolecules such as proteins and DNA, is crucial for comprehending their structure and function. Unfortunately, current methods for label-free, sensitive, and rapid imaging of the surface charge of single DNA molecules are limited. Here, we propose a plasmonic microscopy strategy that utilizes charge-sensitive single-crystal monolayer WS2 materials to image the local charge density of a single λ-DNA molecule. Our study reveals that WS2 is a highly sensitive charge-sensitive material that can accurately measure the local charge density of λ-DNA with high spatial resolution and sensitivity. The consistency of the surface charge density values obtained from the single-crystal monolayer WS2 materials with theoretical simulations demonstrates the reliability of our approach. Our findings suggest that this class of materials has significant implications for the development of label-free, scanning-free, and rapid optical detection and charge imaging of biomolecules.

Investigating atomization characteristics in an electrostatic rotary bell atomizer

Electrostatic rotary bell atomizers are commonly used in several engineering applications, including the automobile industry. A high-speed rotating nozzle operating in a strong background electric field atomizes paint into charged droplets that range from a few micrometers to tens of micrometers in diameter. The atomization process directly determines the droplet size and droplet charge distributions which subsequently control the transfer efficiency and the surface finish quality. We have previously developed a tool to perform high fidelity simulations of near-bell atomization with electrohydrodynamic effects. In this work, we perform simulations employed with a droplet ancestry extraction tool to analyze previously inaccessible information and understand the physical processes driving atomization. We find that the electric field accelerates breakup processes and enhances secondary atomization. The total number of droplets, the ratio of secondary to primary droplets, and the ratio of coalescence to breakup activity are all much higher when operating in an electric field. We analyze the droplet velocity, local Weber number and charge density statistics to understand the complex physics in electrically assisted breakup. The results of the study have helped us gain insights into the physics of atomization in electrostatic rotary sprays.

The Gauge Picture of Quantum Dynamics

Although local Hamiltonians exhibit local time dynamics, this locality is not explicit in the Schrödinger picture in the sense that the wavefunction amplitudes do not obey a local equation of motion. We show that geometric locality can be achieved explicitly in the equations of motion by "gauging" the global unitary invariance of quantum mechanics into a local gauge invariance. That is, expectation values ⟨ψ|A|ψ⟩ are invariant under a global unitary transformation acting on the wavefunction |ψ⟩→U|ψ⟩ and operators A→UAU†, and we show that it is possible to gauge this global invariance into a local gauge invariance. To do this, we replace the wavefunction with a collection of local wavefunctions |ψJ⟩, one for each patch of space J. The collection of spatial patches is chosen to cover the space; e.g. we could choose the patches to be single qubits or nearest-neighbor sites on a lattice. Local wavefunctions associated with neighboring pairs of spatial patches I and J are related to each other by dynamical unitary transformations UIJ. The local wavefunctions are local in the sense that their dynamics are local. That is, the equations of motion for the local wavefunctions |ψJ⟩ and connections UIJ are explicitly local in space and only depend on nearby Hamiltonian terms. (The local wavefunctions are many-body wavefunctions and have the same Hilbert space dimension as the usual wavefunction.) We call this picture of quantum dynamics the gauge picture since it exhibits a local gauge invariance. The local dynamics of a single spatial patch is related to the interaction picture, where the interaction Hamiltonian consists of only nearby Hamiltonian terms. We can also generalize the explicit locality to include locality in local charge and energy densities.

Harmonizing the cyano-group and Na to enhance selective photocatalytic O2 activation on carbon nitride for refractory pollutant degradation

Manipulating exciton dissociation and charge-carrier transfer processes to selectively generate free radicals of more robust photocatalytic oxidation capacity for mineralizing refractory pollutants remains challenging. Herein, we propose a strategy by simultaneously introducing the cyano-group and Na into graphitic carbon nitride (CN) to obtain CN-Cy-Na, which makes the charge-carrier transfer pathways the dominant process and consequently achieves the selective generation of free radicals. Briefly, the cyano-group intensifies the local charge density of CN, offering a potential well to attract the hole of exciton, which accelerates the exciton dissociation. Meanwhile, the separated electron transfers efficiently under the robust built-in electric field induced by the cyano-group and Na, and eventually accumulates in the heptazine ring of CN for the following O2 reduction due to the reinforced electron sink effect caused by Na. As a result, CN-Cy-Na exhibits 4.42 mmol L-1 h-1 productivity with 97.6% selectivity for free radicals and achieves 82.1% total organic carbon removal efficiency in the tetracycline photodegradation within 6 h. Additionally, CN-Cy-Na also shows outstanding photodegradation efficiency of refractory pollutants, including antibiotics, pesticide plastic additives, and dyes. This work presents an innovative approach to manipulating the exciton effect and enhancing charge-carrier mobility within two-dimensional photocatalysts, opening an avenue for precise control of free radical generation.

Tailoring the Degradation Time of Polycationic PEG-Based Hydrogels toward Dynamic Cell Culture Matrices.

Poly(ethylene glycol)-based (PEG) hydrogels provide an ideal platform to obtain well-defined and tailor-made cell culture matrices to enhance in vitro cell culture conditions, although cell adhesion is often challenging when the cells are cultivated on the substrate surface. We herein demonstrate two approaches for the synthesis of polycationic PEG-based hydrogels which were modified to enhance cell-matrix interactions, to improve two-dimensional (2D) cell culture, and catalyze hydrolytic degradation. While the utilization of N,N-(bisacryloxyethyl) amine (BAA) as cross-linker for in situ gelation provides degradable scaffolds for dynamic cell culture, the incorporation of short segments of poly(N-(3-(dimethylamino)propyl)acrylamide) (PDMAPAam) provides high local cationic charge density leading to PEG-based hydrogels with high selectivity for fibroblastic cell lines. The adsorption of transforming growth factor (TGF-β) into the hydrogels induced stimulation of fibrosis and thus the formation of collagen as a natural ECM compound. With this, these dynamic hydrogels enhance in vitro cell culture by providing a well-defined, artificial, and degradable matrix that stimulates cells to produce their own natural scaffold within a defined time frame.

An ultracompact scanning tunneling microscope within a Φ 10 piezo tube in a 20T superconducting magnet.

Low-temperature scanning tunneling microscopy and spectroscopy (STM/S) help to better understand the fundamental physics of condensed matter. We present an ultracompact STM within a Φ 10 piezo tube in a 20T superconducting magnet. The carefully cut piezo tube contains the STM's coarse-positioning assembly. Loading an STM tip-sample mechanical loop into the piezo tube with special cut openings enables an ultracompact pencil-size dimension down to Φ 10mm, in which fine-machined nonmagnetic parts are assembled to enable slide-stick motion and xyz-scanning procedures. The small size leads to a higher resonant frequency, a typical feature of a rigid STM instrument, increasing its vibration immunity. Scanning by moving the sample while keeping the tip stationary improves the stability of the tip-sample junction compared to moving the tip. Taking advantage of its high-field compatibility and rigid design, our STM captures the atomically resolved topography of highly oriented pyrolytic graphite (HOPG) at 1.5K and in magnetic fields up to 17T. The topography of graphene lattice and graphite is simultaneously recorded on an atomic terrace of HOPG, unveiling a modified local charge density at a surface defect. The superconducting energy gaps of layered type-II superconductors NbSe2 and PdBi2 are well resolved through dI/dV tunneling spectra at sub-2K. Our unique STM is highly suitable for potential STM/S applications in world-class high-field facilities where the strong magnetic field can exceed 30T.

Direct Quantifying Charge Transfer by 4D-STEM: A Study on Perfect and Defective Hexagonal Boron Nitride.

Four-dimensional scanning transmission electron microscopy (4D-STEM) offers an attractive approach to simultaneously obtain precise structural determinations and capture details of local electric fields and charge densities. However, accurately extracting quantitative data at the atomic scale poses challenges, primarily due to probe propagation and size-related effects, which may even lead to misinterpretations of qualitative effects. In this study, we present a comprehensive analysis of electric fields and charge densities in both pristine and defective h-BN flakes. Through a combination of experiments and first-principle simulations, we demonstrate that while precise charge quantification at individual atomic sites is hindered by probe effects, 4D-STEM can directly measure charge transfer phenomena at the monolayer edge with sensitivity down to a few tenths of an electron and a spatial resolution on the order of a few angstroms.

Dynamically Reconstructed Triple-Copper-Vacancy Associates Confined in Cu Nanowires Enabling High-Rate and Selective CO2 Electroreduction to C2+ Products.

Electrochemically reconstructed Cu-based catalysts always exhibit enhanced CO2 electroreduction performance; however, it still remains ambiguous whether the reconstructed Cu vacancies have a substantial impact on CO2 -to-C2+ reactivity. Herein, Cu vacancies are first constructed through electrochemical reduction of Cu-based nanowires, in which high-angle annular dark-field scanning transmission electron microscopy image manifests the formation of triple-copper-vacancy associates with different concentrations, confirmed by positron annihilation lifetime spectroscopy. In situ attenuated total reflection-surface enhanced infrared absorption spectroscopy discloses the triple-copper-vacancy associates favor *CO adsorption and fast *CO dimerization. Moreover, density-functional-theory calculations unravel the triple-copper-vacancy associates endow the nearby Cu sites with enriched and disparate local charge density, which enhances the *CO adsorption and reduces the CO-CO coupling barrier, affirmed by the decreased *CO dimerization energy barrier by 0.4eV. As a result, the triple-copper-vacancy associates confined in Cu nanowires achieve a high Faradaic efficiency of over 80% for C2+ products in a wide current density range of 400-800mA cm-2 , outperforming most reported Cu-based electrocatalysts.

Methyl-Symmetrically Substituted Poly(3,4-Dimethylthiophene) as Cathode for Aluminum Ion Batteries.

The aggravation of energy problems and the scarcity of lithium resources have forced us to look for new energy storage systems. Aluminum ion batteries, as a promising energy storage system, have the advantages of environmental friendliness and abundant aluminum resources, and have the potential for application in large-scale energy storage and personal portable electronic devices. To solve the stability problem of aluminum ion batteries during cycling for large-scale energy storage needs, we report a polythiophene-based conductive polymer, poly(3,4-dimethylthiophene) (PDMT), as a high performance cathode material for aluminum ion batteries. By introducing two methyl groups on the thiophene ring, we successfully adjust the local charge density of the heterocyclic thiophene, thus changing the electron delocalization characteristics, and improving the electrochemical reaction activity of the polythiophene (PTH) material as a redox electrode material. This also maintains the symmetry and regularity of the polymer structure, giving the material better cycling stability. The discharge specific capacity reaches 110 mAh g-1 at a current density of 200 mA g-1, far exceeding conventional PTH cathodes (~70 mAh g-1), and the capacity retention rate is 92.7 % after 1000 cycles. It also shows excellent rate performance due to the flexible structure of the conductive polymer.

Nanometer-Resolved Operando Photo-Response of Faceted BiVO4 Semiconductor Nanoparticles.

Photo(electro)catalysis with semiconducting nanoparticles (NPs) is an attractive approach to convert abundant but intermittent renewable electricity into stable chemical fuels. However, our understanding of the microscopic processes governing the performance of the materials has been hampered by the lack of operando characterization techniques with sufficient lateral resolution. Here, we demonstrate that the local surface potentials of NPs of bismuth vanadate (BiVO4) and their response to illumination differ between adjacent facets and depend strongly on the pH of the ambient electrolyte. The isoelectric points of the dominant {010} basal plane and the adjacent {110} side facets differ by 1.5 pH units. Upon illumination, both facets accumulate positive charges and display a maximum surface photoresponse of +55 mV, much stronger than reported in the literature for the surface photo voltage of BiVO4 NPs in air. High resolution images reveal the presence of numerous surface defects ranging from vacancies of a few atoms, to single unit cell steps, to microfacets of variable orientation and degree of disorder. These defects typically carry a highly localized negative surface charge density and display an opposite photoresponse compared to the adjacent facets. Strategies to model and optimize the performance of photocatalyst NPs, therefore, require an understanding of the distribution of surface defects, including the interaction with ambient electrolyte.

Construction of P−N charge-transfer bridge in porous g-C3N4 for highly efficient visible-light-driven photocatalytic N2 fixation

Solar N2 fixation is a green and pollution-free technology to realize solar energy to chemical energy. Here, P doped g-C3N4 nanosheets (PCNx) with porous structure has been fabricated via a one-step calcination process for efficient ammonia generation. The optimal PCN0.6 catalyst provided an improved visible light photo-performance with an ammonia generation rate of 3110 µg L−1h−1g−1, 15 times higher than that for pristine g-C3N4 (CN). And the quantum efficiency at 400 nm monochromatic light reached 3.29%. Characterization results revealed that the implantation of P−N bonds in g-C3N4 resulted in expanded optical response, larger accessible active sites and efficient separation of electron-hole pairs than that of bulk counterpart. Wavefunction contour maps revealed a more localized charge density distribution upon P doping, leading to a favorable electron-rich structure. The calculated N2 adsorption energy and N2-TPD tests showed the strong capacity of nitrogen chem-adsorption by PCN0.6. Charge density differences and Bader charge demonstrated the electrons transfer from the P doping sites of g-C3N4 to adsorbed N2, thus activating N2 molecules for effective NH4+ generation. This work offered significant insights into the heteroatom doping engineering to construct active sites and steer the charge migration pathways in g-C3N4 for efficient photo-reduction of N2.

Dynamically tunable moiré exciton Rydberg states in a monolayer semiconductor on twisted bilayer graphene.

Moiré excitons are emergent optical excitations in two-dimensional semiconductors with moiré superlattice potentials. Although these excitations have been observed on several platforms, a system with dynamically tunable moiré potential to tailor their properties is yet to be realized. Here we present a continuously tunable moiré potential in monolayer WSe2, enabled by its proximity to twisted bilayer graphene (TBG) near the magic angle. By tuning local charge density via gating, TBG provides a spatially varying and dynamically tunable dielectric superlattice for modulation of monolayer WSe2 exciton wave functions. We observed emergent moiré exciton Rydberg branches with increased energy splitting following doping of TBG due to exciton wave function hybridization between bright and dark Rydberg states. In addition, emergent Rydberg states can probe strongly correlated states in TBG at the magic angle. Our study provides a new platform for engineering moiré excitons and optical accessibility to electronic states with small correlation gaps in TBG.

Facet-Dependent Charge Density of Serpentine: Nanoscopic Implications for Aggregation and Entrainment of Fine Particles.

Deciphering the facet-dependent surface properties of clay minerals holds vital significance in both fundamental research and practical engineering applications. To date, the anisotropic local charge density of serpentine surfaces still remains elusive, and thus, the interaction energies and associated aggregate structures between different crystal planes of serpentine cannot be quantitatively determined. In this work, different crystal planes of serpentine (i.e., SiO basal, MgOH basal, and edge) were selectively exposed, and their surface potentials and charge densities were determined using atomic force microscopy (AFM) force measurements coupled with Derjaguin-Landau-Verwey-Overbeek (DLVO) theory fitting. The SiO and edge planes consistently exhibited a permanently negative surface charge, whereas the point of zero charge (PZC) on the MgOH plane was estimated to be pH 9.0-11.0. Based on the interaction energy calculation between different serpentine planes, the aggregation structures of serpentine were predicted. Combined with scanning electron microscopy observation of freeze-dried samples, SiO-MgOH and MgOH-edge associations were found to dominate the aggregate structures at pH ≤ 9.0, thereby resulting in a stacking or "card-houses" structures. In contrast, all of the plane associations exhibited the repulsive interaction energy at pH 11.0, which led to a completely dispersed system, ultimately causing the most severe fine particle entrainment during froth flotation. Our work provides quantitative clarification of facet-dependent surface properties and aggregate structures of serpentine under different pH conditions, which will help improve the fundamental understanding of colloidal behaviors of clay minerals.

Imaging Structural and Electrical Changes of Aging Cells Using Scanning Ion Conductance Microscopy.

The local charge density and distribution of extracellular membranes play a crucial role in the various cellular processes, such as regulation and localization of membrane proteins, electrophysiological signal transduction, transcriptional control, cell growth, and cell death. In this study, a novel scanning ion conductance microscopy-based method is employed to extracellular membrane mapping. This method allows to not only visualize the dynamic topography and surface charge distribution around individual cells, but also distinguish the charge difference. To validate the accuracy and effectiveness of this method, the charge density on model sample surfaces are initially manipulated and the charge sensing mechanism using finite element modeling (FEM) is explored subsequently. By applying this method, both the extracellular charge distributions and topography structures of normal and senescent human dental pulp stem cells (hDPSCs) are able to monitor. Interestingly, it is observed that the surface charge became significantly more negative after cellular senescence. This innovative approach enables us to gain valuable insights into surface charge changes during cellular senescence, which can contribute to a better understanding of the underlying mechanisms and potential therapeutic strategies for age-related diseases.

Electro-Responsive Breathing Transition of Conductive Hydrogel for Broadband Kinetic Energy Harvesting.

Reclaiming kinetic energy from vibrating machines holds great promise for sustainable energy harvesting technologies. Nevertheless, the impulsive current induced by vibrations is incompatible with conventional energy storage devices. The energy-management system necessitates novel designs of soft materials for lightweight, miniaturized, and integrated high-frequency electrochemical devices. Here, this work develops a conductive hydrogel with an electro-responsive polymeric network. The electro-responsive breathing transition of the crosslinking points facilitates the expeditious formation of a localized electrolyte layer. This layer features an exceedingly high local charge density, surpassing that of a saturated electrolyte solution by an order of magnitude, and thus enabling rapid charge transport under the influence of an applied voltage. The micro-capacitor based on the gel exhibits record-high capacitance of ≈2 mF cm-2 when the frequency of energy input reaches up to 104 Hz. This work also demonstrates a prototype battery charger that harvests energy from a running car engine. This study presents a feasible strategy for waste energy recycling using integrated electrochemical devices, opening a new avenue for ambient energy management.

Meson spectrum of SU(2) QCD1+1 with quarks in Large representations

We consider SU(2) quantum chromodynamics in 1 + 1 dimensions with a single quark in the spin J representation of the gauge group and study the theory in the large J limit where the gauge coupling g2 → 0 and J → ∞ with λ = g2J2 fixed. We work with a Dirac spinor field for arbitrary J, and with a Majorana spinor for integer J since the integer spin representations of SU(2) are real, and analyze the two cases separately.The theory is reformulated in terms of global colour non-singlet fermion bilocal operators which satisfy a W∞ × U(2J + 1) algebra. In the large J limit, the dynamics of the bilocal fields is captured by fluctuations along a particular coadjoint orbit of the W∞ algebra. We show that the global colour-singlet sector of the bilocal field fluctuations satisfy the same integral equation for meson wavefunctions that appears in the ’t Hooft model. For Majorana spinors in the integer spin J representation, the Majorana condition projects out half of the meson spectrum, as a result of which the linear spacing of the asymptotic meson spectrum for Majorana fermions is double that of Dirac fermions. The Majorana condition also projects out the zero mass bound state that is present for the Dirac quark at zero quark mass.We also consider the formulation of the model in terms of local charge densities and compute the quark spectral function in the large J limit: we see evidence for the absence of a pole in the quark propagator.

Interface regulation of Zr-MOF/Ni2P@nickel foam as high-efficient electrocatalyst for pH-universal hydrogen evolution reaction

Currently, the development of economical and effective non-noble metal electrocatalysts is vital for advancing hydrogen evolution reaction (HER) and enabling its widespread applications. The customizable pore structure and enormous surface area of metal–organic frameworks (MOFs) have made them to become promising non-noble metal electrocatalysts for HER. However, MOFs have some challenges, including low conductivity and instability, which can result in them having high overpotentials and slow reaction kinetics in electrocatalytic processes. In this work, we present an innovative approach for synthesizing cost-effective and high-efficient Zr-MOF-derived pH-universal electrocatalysts for HER. It entails creating the interfaces of the electrocatalysts with suitable proportions of phosphide nanostructures. Zr-MOF/Ni2P@nickel foam (NF) electrodes with interface regulated by Ni2P nanostructures were successfully developed for high-efficient pH-universal HER electrocatalysts. The presence of Ni2P nanostructures with abundant active sites at the Zr-MOFs@NF interfaces boosted the electronic conductivity and local charge density of the hybrid electrocatalysts. This helped to improve their reaction kinetics and electrocatalytic activity. By optimizing the Ni2P amount, Zr-MOF/Ni2P@NF demonstrated impressive stability and superior HER activities, with a low overpotential of 149 mV (acidic electrolytes) and 143 mV (alkaline electrolytes) at 10 mA cm−2. The proven strategy in this work can be expanded to many types of MOF-based materials for wider practical applications.

Deposition Mode Design of Li2S: Transmitted Orbital Overlap Strategy in Highly Stable Lithium‐Sulfur Battery

AbstractSerious lithium polysulfides (LiPSs) shuttle effect and slow kinetic process lead to poor cycle performance and low working efficiency of lithium‐sulfur battery (Li‐S battery), which limits its commercialization. In this paper, a composite frame with transmitted orbital overlap is proposed as the functionalized separator of Li‐S battery (MX@WSSe/PP). It consists of WSSe nanosheets and MXenes nanosheets (MX). The experiments and theoretical calculations both show that MX@WSSe/PP can not only inhibit the LiPSs shuttle effect to realize the effective utilization of cathode materials, but also enhance the overall reversibility and reaction kinetics of the device by transforming the 2D deposition mode of Li2S into 3D mode. The transformation of Li2S deposition mode comes from the changed local charge density on MX@WSSe composite surface, which regulates the filling state of electron orbits and affects the orbital overlap between different atoms. This effect can even be transmitted to Li2S molecules far from the surface of MX@WSSe. The capacity decay per cycle of Li‐S battery with MX@WSSe/PP is only 0.016% in 1000 cycles at 2 C. Also, a high area capacity of 9.39 mAh cm−2 is achieved at high sulfur loading (10.2 mg cm−2) and low electrolyte/sulfur ratio (7.5 µL mg−1).

The oxygen-doped self-supporting functional carbon nanotube sponge realized the synergistic enhancement of lithium ion transport and lithium polysulfide reaction

Lithium-sulfur (Li-S) batteries are one of the most promising energy storage systems, in which the severe shuttle effect causes the loss of the sulfur active species and unacceptable capacity and cycling stability. Here, a self-supporting functional carbon nanotube sponge (FCNTS), electrostatically repelling polysulfide anions and allowing Li+ to pass through, is synthesized by etching channels and introducing enriched anions on CNTs based on the “Donnan effect”. The experimental results confirmed that FCNTS accelerated the Li-ion transport, that is, the Li+ transfer rates of the FCNTS materials were 8.226 (Li2S4 reduction) and 3.627 times (Li2S oxidation) that of the CNTs blank samples, respectively. Meanwhile, defects and O-group modified FCNTS regulated the local charge density of carbon-based materials, which enriched the reduction current response of the soluble Li2S4 and the oxidation current of Li2S2/Li2S around the cathode more than 1.9 and 1.6 times that of the CNTs blank samples, respectively. This significantly improved the kinetics and suppressed the overpotential. Thus, the cells assembled by S@FCNTS achieved a high-rate performance (866.9 mAh∙g−1 at 2 C), excellent stability (fading rate of only 0.035% per cycle after 500 cycles at 2 C), and a high area capacity of 13.2 mAh∙cm−2 at a high sulfur load of 10.9 mA∙cm−2. This work demonstrates a dynamic polysulfide-interception strategy to facilitate the utilization of polysulfides and provides a promising idea for the design of multi-functional sulfur storage electrode materials for high-load LSBs.

Proof of crystal-field-perturbation-enhanced luminescence of lanthanide-doped nanocrystals through interstitial H+ doping

Crystal-field perturbation is theoretically the most direct and effective method of achieving highly efficient photoluminescence from trivalent lanthanide (Ln3+) ions through breaking the parity-forbidden nature of their 4f-transitions. However, exerting such crystal-field perturbation remains an arduous task even in well-developed Ln3+-doped luminescent nanocrystals (NCs). Herein, we report crystal-field perturbation through interstitial H+-doping in orthorhombic-phase NaMgF3:Ln3+ NCs and achieve a three-orders-of-magnitude emission amplification without a distinct lattice distortion. Mechanistic studies reveal that the interstitial H+ ions perturb the local charge density distribution, leading to anisotropic polarization of the F− ligand, which affects the highly symmetric Ln3+-substituted [MgF6]4− octahedral clusters. This effectively alleviates the parity-forbidden selective rule to enhance the 4f–4 f radiative transition rate of the Ln3+ emitter and is directly corroborated by the apparent shortening of the radiative recombination lifetime. The interstitially H+-doped NaMgF3:Yb/Er NCs are successfully used as bioimaging agents for real-time vascular imaging. These findings provide concrete evidence for crystal-field perturbation effects and promote the design of Ln3+-doped luminescent NCs with high brightness.