Three-dimensional Quantum Dot Research Articles

Three-dimensional nitrogen-doped graphene quantum dot/Ag leaf/Cu2O-Cu trunk/nickel foam nanocomposites as ultra-high-efficiency cathode electrocatalysts for hydrogen evolution reaction applications

In this study, we developed a three-dimensional (3D) nitrogen-doped graphene quantum dot (NGQD)/Ag leaf/Cu₂O-Cu trunk/nickel foam (NF) structure as a high-performance electrocatalyst for hydrogen evolution reaction (HER) applications. This novel structure exhibited a high surface area, abundant electrochemically active sites, and efficient electronic transmission networks. In alkaline solution, the proposed structure demonstrated an overpotential of 112 mV at a current density of 10 mA/cm2, along with a low Tafel slope of 28 mV dec−1, indicating excellent HER activity. Furthermore, the structure exhibited stability over 100 h during durability testing. Overall, this innovative structure experimentally confirms that Cu-based materials can serve as efficient electrocatalysts for HER applications.

Chiral 3D structures through multi-dimensional transfer printing of multilayer quantum dot patterns

Three-dimensional optical nanostructures have garnered significant interest in photonics due to their extraordinary capabilities to manipulate the amplitude, phase, and polarization states of light. However, achieving complex three-dimensional optical nanostructures with bottom-up fabrication has remained challenging, despite its nanoscale precision and cost-effectiveness, mainly due to inherent limitations in structural controllability. Here, we report the optical characteristics of intricate two- and three-dimensional nanoarchitectures made of colloidal quantum dots fabricated with multi-dimensional transfer printing. Our customizable fabrication platform, directed by tailored interface polarity, enables flexible geometric control over a variety of one-, two-, and three-dimensional quantum dot architectures, achieving tunable and advanced optical features. For example, we demonstrate a two-dimensional quantum dot nanomesh with tuned subwavelength square perforations designed by finite-difference time-domain calculations, achieving an 8-fold enhanced photoluminescence due to the maximized optical resonance. Furthermore, a three-dimensional quantum dot chiral structure is also created via asymmetric stacking of one-dimensional quantum dot layers, realizing a pronounced circular dichroism intensity exceeding 20°.

A three-dimensional quantum dot network stabilizes perovskite solids via hydrostatic strain

A three-dimensional quantum dot network stabilizes perovskite solids via hydrostatic strain

High-Performance Near-Infrared Photodetector by Integration of PbS Quantum Dots With 3D-Graphene

Achieving breakthroughs in high-performance near-infrared (NIR) photodetectors (PDs) relies on selecting materials and designing device structures. This work shows the synergistic effect between three-dimensional graphene (3D-graphene) and PbS quantum dots (PbS QDs) in the PD structure design, achieved by in-situ growth of 3D-graphene on the silicon (Si) substrate, followed by PbS QDs modification on the 3D-graphene surface. The high-performance NIR PD based on PbS QDs/3D-graphene/Si heterojunction is realized. The synergistic effect of 3D-graphene with strong light absorption and the effective built-in potential modulation by PbS QDs lead to the high detectivity (1×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sup> Jones) and responsivity (13.7 A/W) of the as-fabricated PD at 1550 nm.

Dimensional effect of graphene nanostructures on cytoskeleton-coupled anti-tumor metastasis.

Interactions between inorganic materials and living systems can be strongly influenced by the dimensional property of the materials, which can in turn impact biological activities. Although the role of biomaterials at the molecular and cellular scales has been studied, research investigating the effects of biomaterials across multiple dimensional scales is relatively scarce. Herein, comparing the effectiveness of two-dimensional graphene oxide nanosheets (GOs) and three-dimensional graphene oxide quantum dots (GOQDs) (though not zero-dimensional because of their significant surface area) in cancer therapies, we have discovered that GOs, with the same mass concentration, exhibit stronger anti-cancer and anti-tumor metastasis properties than GOQDs. Our research, which employed liquid-phase atomic force microscopy, revealed that lower-dimensional GOs create a more extensive nano-bio interface that impedes actin protein polymerization into the cytoskeleton, leading to the prevention of tumor metastasis. These results help to better understand the underlying mechanisms and offer a dimensional perspective on the potential of optimizing the properties of graphene-based materials for clinical applications, e.g., cancer therapy.

Spin-orbit interaction effect on a hydrogenic [formula omitted] centre in a three-dimensional asymmetric Gaussian GaAs quantum dot in a magnetic field

The binding energy of a hydrogenic neutral D0 complex situated in a three-dimensional asymmetric Gaussian GaAs quantum dot is studied incorporating the Rashba and Dresselhaus spin-orbit interactions and the effect of an external magnetic field by means of a variational method and its variation with respect to the quantum dot size, strength of the magnetic field, donor position and spin-orbit coupling strengths is calculated. The behavior of the magnetic susceptibility of the system is also investigated with respect to the magnetic field for different values of the quantum dot parameters.

Synergy of Block Copolymers and Perovskites: Template Growth through Self-Assembly.

Block copolymers (BCPs) have been widely used as templates to prepare nanostructures over the past few decades. Ordered nanostructures can be formed after microphase segregation of BCPs. In this context, the newly emerging BCP-templated perovskites, in which the perovskite crystal growth has been confined within a self-assembled BCP nanostructure due to the interaction between the polymer block and the cation of the perovskite, have shown profound optical performance and environmental stability. Considering the promising performance of BCP-templated perovskites, this Perspective comprehensively reviews recent works in which BCPs are used as templates with three-dimensional perovskites and perovskite quantum dots, and their performance and stability are thoroughly discussed. Lastly, their potential applications in optoelectronics and biology are discussed.

The Effect of Magnetic Field on the Thermodynamic Properties of Three-Dimensional GaAs Quantum Dot

The problem of parabolically single three-dimensional semiconductor GaAs quantum dot in the presence of an external magnetic field and including the spin of the electron is studied using canonical formalism. The energy spectrum is obtained as a function of temperature and magnetic field. It is observed that the system tends to absorb the largest amount of heat at critical values of the magnetic field which depends on the temperature. A schottky-like anomaly in heat capacity is observed at low temperature, while at high temperature it converges rapidly and saturates. It was also found that the entropy is inversely proportional to the magnetic field strength, also entropy showed exciting behavior at low temperature, a shoulder is observed which becomes curvier when the magnetic field decreases. However, at high temperature, entropy increases monotonically with temperature and becomes essentially independent of the magnetic field. The substantial effect of magnetic field on the magnetic properties of quantum dot is observed at low temperature. It is shown that, magnetization increases significantly at low temperature and shows strong dependence on magnetic field, while its magnitude increases as the temperature increases and reduces to zero regardless the value of magnetic field strength. In addition, at low temperature susceptibility peaks and is found to be paramagnetic and at high temperature the diamagnetic state is found to be a favored state of the system and susceptibility becomes completely independent of magnetic field. It is also shown that for a fixed value of temperature, susceptibility increases rapidly with magnetic field and beyond a critical value of magnetic field, the increase becomes much slower, susceptibility exhibits a crossing behavior, and magnetization shows a significant drop as the magnetic field increases. So far, no study has been made in literature on the effect of magnetic field on the thermal and magnetic properties of three-dimensional quantum dot.

Constraint Mechanism of Power Device Design Based on Perovskite Quantum Dots Pumped by an Electron Beam.

This paper studied the constraint mechanism for power device design based on perovskite quantum dots pumped by an electron beam. Combined with device designing, an experimental system of self-saturation luminescence and aging failure was designed for CsPbBr3 films. On this basis, we further completed the self-saturation luminescence and aging failure experiment and constructed a model of self-saturation luminescence and aging failure for CsPbBr3 device designing. Three constraints were proposed after analyzing and discussing the experimental data. Firstly, too high of a pumping current density makes it difficult to effectively promote the enhancement of luminescence efficiency. Secondly, radiation decomposition and aging failure of CsPbBr3 films are mainly related to the polarized degree of CsPbBr3 nanocrystals. Thirdly, by increasing the pumping electric field, the pumping energy can be effectively and widely delivered to the three-dimensional quantum dots film layer space, and there is a nonlinear relationship between the attenuation of the pumping energy density and the increment of the pumping electric field, which will effectively avoid the local high-energy density of instantaneous optical pumping.

Self-Supported Three-Dimensional Quantum Dot Aerogels as a Promising Photocatalyst for CO2 Reduction

Self-Supported Three-Dimensional Quantum Dot Aerogels as a Promising Photocatalyst for CO₂ Reduction

Reversible Zn2+-induced 3D self-assembled aerogel of carboxyl modified copper indium diselenide quantum dots: mechanism and application for inkjet printing anti-counterfeiting.

Three-dimensional (3D) self-assembled quantum dot (QD) aerogels have attracted attention due to the combined properties of both QDs and porous materials. However, the difficulty and complexity of structural composition control limit the practical application of 3D self-assembled QDs. Hence, convenient, available and multifunction QD aerogels need to be explored to promote broader practical applications. Herein, we propose a universal and facile self-assembly method of copper indium selenium (CISe) QD aerogels based on coordination interaction between Zn2+ and carboxyl. Both experiments and Monte Carlo simulations indicate that QDs are aggregated into oligomers by Zn2+, and then the oligomers are gradually interconnected to each other to form a 3D network as the concentration of Zn2+ increases. Moreover, Zn2+-induced 3D self-assembled aerogel could be depolymerized by EDTA reversibly. In combination with CISe QDs, Zn-CISe aerogel has been successfully applied in green pollution-free environment-friendly anti-counterfeiting and encryption systems.

Multicomponent perovskite superlattices

Multicomponent perovskite superlattices

High thermoelectric figure of merit of quantum dot array quantum wires

How to design silicon-based quantum wires with a figure of merit (ZT) larger than three is under hot pursuit due to the advantage of low cost and the availability of matured fabrication techniques. Quantum wires consisting of finite three-dimensional quantum dot (QD) arrays (QDAs) coupled to electrodes are proposed to realize high efficient thermoelectric devices with optimized power factors. The transmission coefficient of 3D QDAs can exhibit 3D, 2D, 1D and 0D topological distribution functions by tailoring the interdot coupling strengths. Such topological effects on the thermoelectric properties are revealed. The 1D topological distribution function shows the maximum power factor and the best ZT value. We have demonstrated that 3D silicon QDA nanowires with diameters below 20 nm and length 250 nm show high potential to achieve ZT ≥ 3 near room temperature.

Dependence of nonlinear optical properties on electrostatic interaction in an excitonic parabolic quantum dot in a static magnetic field

The linear and the third-order nonlinear optical properties of an exciton confined in a three-dimensional quantum dot with a parabolic potential are studied in a static magnetic field. Eigenvalues, wave functions, dipole matrix elements and selection rules are calculated analytically. Based on the calculated energies and wave functions, within the effective mass approximation, a compact-density matrix approach is employed to analyse the absorption coefficients and refractive index changes. The study is first of its kind since the excitonic effects are studied in a static magnetic field considering both the confinement potential and the electrostatic interaction between the electron-hole pair. An important finding of our research is the dependence of the magnitude of absorption coefficients on the radius of the quantum dot, the result that may have broad implications in future device designing.

Three-dimensional self-attaching perovskite quantum dots/polymer platform for efficient solar-driven CO2 reduction

A well-designed scaffold that allows the full exposure of nanophotocatalyst to reactants is equally important with an efficient catalyst material in realizing a high-performance photocatalytic reaction. In this work, we develop a three-dimensional (3D) bandgap tunable perovskite quantum dots (PQDs)/polyethersulfone (PES) monolithic film to maximize the specific area and enhance light harvesting, thereby making full use of PQDs in solar-driven CO2 reduction. The PQDs are electrostatically self-attached to the 3D PES scaffold with minimal agglomeration and clustering so that can be fully exposed to gaseous reactant and sustaining its superior high surface/volume ratio. Through composition engineering, the small-bandgap I-rich CsPbIxBr3-x PQDs along with the 3D PES scaffold achieve a high electron consumption rate of 64.90 μmol g−1 h−1, exceeding all the reported PQD-based single photocatalysts in CO2 photoreduction. Our work provides a new platform to fully exploit the perovskite nanomaterials by constructing 3D nanocatalyst/polymer film for highly efficient photocatalytic reactions.

Influence of quantum dot shape on energy spectra of three-dimensional quantum dots superlattices

The band spectrum of quantum dots superlattices of different shapes at points of high symmetry is determined. Cubic, cylindrical and spherical quantum dots are considered. The width of the minizone is calculated. The dependences of the minizones on the geometric dimensions of quantum dots and their concentration are established.

Improved electrocatalytic performance from graphene quantum dots/three-dimensional graphene/polyaniline doped powder to layer-by-layer self-assembled membrane materials

In this paper, three-dimensional network graphene and graphene quantum dots were prepared using graphite powder as the initial raw material. After that, the method of self-assembly of graphene quantum dots (GQDs) on the surface of three-dimensional graphene (3D-G) was used to prepare GQDs/3D-G composite to solve the problem of easy agglomeration of graphene in the process of composite preparation, and then it was mixed with polyaniline (PANI) aqueous solution in different contents to form graphene quantum dots/three-dimensional graphene/polyaniline (GQDs/3D-G/PANI) doped composite. The obtained GQDs/3D-G/PANI doped materials exhibited a specific morphology of nanoscale polyaniline firmly attached to the 3D networked graphene layer, which was attributed to the good dispersion of 3D network graphene and polyaniline in water. Graphene quantum dots facilitated close contact between the three-dimensional graphene sheet and the polyaniline particles, which significantly reduced agglomeration. In addition, driven by the strong electrostatic force between the positively charged polyaniline and the negatively charged GQDs/3D-G and the π-π interaction, the nano-scale GQDs/3D-G/PANI thin film layer was obtained by layer-by-layer self-assembly on the hydroxylated ITO plate, which showed the morphology of an interconnected layer network and exhibited good electrochemical catalytic activity for H2O2.

Temperature and resultant dipole moment of an off-center D- impurity in a Gaussian quantum dot

Abstract The present study investigates the variation of energy ( E ), binding energy ( E B ) and the resultant dipole moment ( D p ) of a negative donor impurity ( D − ) with on-center and off-center locations ( d ) in a GaAs three-dimensional quantum dot (3D-QD) modelled with a Gaussian confinement potential. I have performed Ritz-variational method (RVM) with a very simple wave function which contains just three-variational parameters and a Jastrow-like factor. For on-center ( D − ) impurity, it is true from [47,50] and present results that the E B is always positive and maximum at a particular size of the QD ( R c ). For off-center ( D − ) impurity especially for a large value of locations ( d ) the ( E B ) can be negative. These situations imply that the stability and instability of the system for a given range of the quantum dot size ( R ), respectively. I have obtained the temperatures of D 0 , D − impurities at which these impurities are more stable in a 3D-QD. The confinement length ( R ) and the confinement strength ( V 0 ) effects, on the resultant dipole moment ( D p ) are also investigated for various values of the impurity locations ( d ).

Quasi-Two-Dimensional Diffusion in Adherent Cells Revealed by Three-Dimensional Single Quantum Dot TrackingThis work was supported by the National Natural Science Foundation of China (Grant Nos. 11674383, 11874415, 21991133, and 11774407), the National Key Research and Development Program (Grant No. 2016YFA0301500), the Youth Innovation Promotion Association of CAS (Grant No. 2019006), and the Fundamental Research Funds for the Central Universities (Grant

Intracellular diffusion is critical for molecule translocation in cytoplasm and mediates many important cellular processes. Meanwhile, the diffusion dynamics is affected by the heterogeneous cytoplasm. Previous studies on intracellular diffusion are mainly based on two-dimensional (2D) measurements under the assumption that the three-dimensional (3D) diffusion is isotropic. However, the real behaviors of 3D diffusion of molecules in cytoplasm are still unclear. Here, we have built a 3D single-particle tracking (SPT) microscopy and studied the 3D diffusion of quantum dots (QDs) in adherent A549 cells. Notably, we found that the intracellular diffusion of QDs is quasi-2D, with the axial motion being severely confined. Further investigations demonstrated that disrupting the cytoskeleton component or endoplasmic reticulum (ER) does not alter the quasi-2D diffusion pattern, although ER reduces the diffusion rates and slightly relieves the constraint in the axial diffusion. The preferred quasi-2D diffusion is quite robust and attributed to the complex cytoarchitectures in the flat adherent cells. With the aid of 3D SPT method, the quasi-2D diffusion in cells was revealed, shedding new light on the physical nature of cytoplasm.

Mo-Doped Zn, Co Zeolitic Imidazolate Framework-Derived Co9S8 Quantum Dots and MoS2 Embedded in Three-Dimensional Nitrogen-Doped Carbon Nanoflake Arrays as an Efficient Trifunctional Electrocatalysts for the Oxygen Reduction Reaction, Oxygen Evolution Reaction, and Hydrogen Evolution Reaction.

Herein, we first propose a facile strategy to synthesize Co9S8 and MoS2 nanocrystals embedded in porous carbon nanoflake arrays supported on carbon nanofibers (Co9S8-MoS2/N-CNAs@CNFs) by the pyrolysis of Mo-doped Zn, Co zeolitic imidazolate framework grown on carbon nanofibers and subsequent sulfuration. The electrocatalyst shows high and stable electrocatalytic performance, with a half-wave potential of 0.82 V for oxygen reduction reaction and an overpotential at 10 mA cm-2 for oxygen evolution reaction (0.34 V) and hydrogen evolution reaction (0.163 V), which outperform the metal-organic framework-derived transition metal sulfide catalysts reported so far. Furthermore, the Co9S8-MoS2@N-CNAs@CNFs are employed as an air cathode in a liquid-state and all-solid-state zinc-air battery, presenting high power densities of 222 and 96 mW cm-2, respectively. Such excellent catalytic activities are mainly owing to the unique three-dimensional structure and chemical compositions, optimal electronic conductivity, adequate surface area, and the abundance of active sites. Thus, this work provides an important method for designing other metal-organic framework-derived three-dimensional structural sulfide quantum dot multifunctional electrocatalysts for wider application in highly efficient catalysis and energy storage.