Top Research Papers on Quantum Dots

: We investigated the temperature-dependent photoluminescence spectroscopy of colloidal InZnP/ZnSe/ZnS (core/ shell/shell) quantum dots with varying ZnSe and ZnS shell thickness in the 278~363 K temperature range. Temperature-dependent photoluminescence of the InZnP-based quantum dot samples reveal red-shifting of the photoluminescence peaks, thermal quenching of photoluminescence, and broadening of bandwidth with increasing temperature. The degree of band-gap shifting and line broadening as a function of temperature is affected little by shell composition and thickness. However, the thermal q...

We demonstrate the quantum Mpemba effect in a quantum dot coupled to two reservoirs, described by the Anderson model. We show that the system temperatures starting from two different initial values (hot and cold) cross each other at finite time (and thereby reverse their identities; i.e., hot becomes cold and vice versa) to generate thermal quantum Mpemba effect. The slowest relaxation mode believed to play the dominating role in Mpemba effect in Markovian systems does not contribute to such anomalous relaxation in the present model. In this connection, our analytical result provides necessary...

The great potential of quantum dots (QDs) in photonic quantum information technology is discussed in depth and modern methods and technical solutions for the epitaxial growth and for the deterministic nanoprocessing of quantum devices based on QDs are presented.

Carbon-based quantum dots and their nanocomposites have sparked immense interest for researchers as sensors due to their attractive physico-chemical properties caused by edge effects and quantum confinement. In this review article, we have discussed the synthesis and application of nanocomposites of graphene quantum dots (GQDs) and carbon quantum dots (CQDs). Different synthetic strategies for CQDs, GQDs, and their nanocomposites, are categorized as top-down and bottom-up approaches which include laser ablation, arc-discharge, chemical oxidation, ultrasonication, oxidative cleavage, microwave ...

Worldwide, enormous efforts are directed toward the development of the so‐called quantum internet. Turning this long‐sought‐after dream into reality is a great challenge that will require breakthroughs in quantum communication and computing. To establish a global, quantum‐secured communication infrastructure, photonic quantum technologies will doubtlessly play a major role, by providing and interfacing essential quantum resources, for example, flying‐ and stationary qubits or quantum memories. Over the last decade, significant progress has been made in the engineering of on‐demand quantum ligh...

Methods for the chemical control of Auger recombination and Auger cooling are discussed in the context of how they illuminate the underlying mechanisms, and the current understanding of carrier multiplication in quantum dots is examined.

Aspect of the present invention provides a method for producing such a quantum dot, a plurality of quantum dots.

Quantum dots (QDs) are a unique type of nanocrystalline semiconductor whose electronic and optical properties are dependent on the size and shape of the dots. Diameters of these particles can range from about 2-10 nm, on the order of 10-50 atomic lengths6. The small size of the particle gives a high ratio of surface-to-volume, so their properties fall somewhere between that of individual molecules and bulk semiconductors Quantum dots can be single elements (such as silicon, germanium, etc.) or compounds (CdSe, CdS, etc.)6.

Materials Science A wide range of materials can now be synthesized into semiconducting quantum dots. Because these materials grow from solutions, there is scope to combine quantum dots into devices by using simple, low-cost manufacturing processes. Kagan et al. review recent progress in tailoring and combining quantum dots to build electronic and optoelectronic devices. Because it is possible to tune the size, shape, and connectivity of each of the quantum dots, there is potential for fabricating electronic materials with properties that are not available in traditional bulk semiconductors. S...

Abstract Carbon quantum dots (CDs) are “small” carbon nanostructures with excellent photoluminescence properties, together with low‐toxicity, high biocompatibility, excellent dispersibility in water as well as organic solvents. Due to their characteristics, CDs have been studied for a plethora of applications as biosensors, luminescent probes for photodynamic and photothermal therapy, fluorescent inks and many more. Moreover, the possibility to obtain carbon dots from biomasses and/or organic waste has strongly promoted the interest in this class of carbon‐based nanoparticles, having a promisi...

We investigate whether and how the quantum Zeno effect, i.e., the inhibition of quantum evolution by frequent measurements, can be employed to isolate a quantum dot from its surrounding electron reservoir. In contrast to the often studied case of tunneling between discrete levels, we consider the tunnelling of an electron from a continuum reservoir to a discrete level in the dot. Realizing the quantum Zeno effect in this scenario can be much harder because the measurements should be repeated before the wave packet of the hole left behind in the reservoir moves away from the vicinity of the dot...

We report the theoretical results of improved solar cell efficiency form InAs quantum dots (QDs) embedded in the intrinsic region of n-i-p GaAs structure. The effect of QD layers on the QD solar cell parameters is explained in detail. For QD layers of 250, we obtained a maximum efficiency of 27.4%. Increasing the number of layers beyond the optimum value resulted in the decrease of efficiency. The presence of InAs QD layers in the cell structure results in a significant rise of the short circuit current density from 33.4 mA/cm2 without InAs QD to 45.4 mA/cm2 in the presence of InAs QD. At the ...

Quantum dot is the important part of nanometre science and technology,quantum dot devices is one of development directions of nanometre devices.The classification,major method of preparation of quantum dot are introduced.Study on characteristic of quantum dot,the appalication of quantum dot devices and noise suppression are discussed.

This review explores the applications of CQDs in bioimaging and biomedicine, highlighting recent advancements and future possibilities to increase interest in their numerous advantages for therapeutic applications.

As understanding of the degradation mechanisms of QDs increases and more stable QDs and display devices are developed, QDs are expected to play critical roles in advanced display applications.

Lead sulfide (PbS) colloidal quantum dots (CQDs) are promising materials for next-generation flexible solar cells because of near-infrared absorption, facile bandgap tunability, and superior air stability. However, CQD devices still lack enough flexibility to be applied to wearable devices owing to the poor mechanical properties of CQD films. In this study, a facile approach is proposed to improve the mechanical stability of CQDs solar cells without compromising the high power conversion efficiency (PCE) of the devices. (3-aminopropyl)triethoxysilane (APTS) is introduced on CQD films to streng...

Oriented attachment of colloidal quantum dots allows the growth of two-dimensional crystals by design, which could have striking electronic properties upon progress on manipulating their conductivity. Here, we explore the origin of doping in square and epitaxially fused PbSe quantum dot superlattices with low-temperature scanning tunneling microscopy and spectroscopy. Probing the density of states of numerous individual quantum dots reveals an electronic coupling between the hole ground states of the quantum dots. Moreover, a small amount of quantum dots shows a reproducible deep level in the ...

The current progress in LEDs based on cg-QDs is summarized, mainly concentrating on their synthesis and advantages in addressing the great challenges in QLEDs, like efficiency roll-off at high current densities, short operation lifetimes at high brightness, and low brightness near the voltage around the bandgap.

Abstract Because of their prospective applications and exceptional features, graphene quantum dots (GQDs) have gotten a lot of recognition as a new class of fluorescent carbon materials. One of the carbon family’s newest superstars is the GQD. Due to its exceptional optoelectrical qualities, it has sparked a lot of curiosity since its debut in 2008. Two of the most important traits are a band gap that is not zero, biocompatibility, and highly changeable characteristics. GQDs have several important characteristics. GQDs have shown potential in a variety of fields, for instance, catalysis, sensi...

Challenges remain in scaling up these technologies for commercial use and ensuring their long-term stability and safety, necessitating future research focused on sustainable, scalable solutions that can be integrated into existing systems.

Quantum Dots, existing as a zero-dimensional nanocrystal containing bundles of infinite energy, existing as a zero-dimensional nanocrystal containing bundles of infinite energy are highlighted.

Planar germanium quantum wells have recently been shown to host hard-gapped superconductivity. Additionally, quantum dot spin qubits in germanium are well-suited for quantum information processing, with isotopic purification to a nuclear spin-free material expected to yield long coherence times. Therefore, as one of the few group IV materials with the potential to host superconductor-semiconductor hybrid devices, proximitized quantum dots in germanium is a compelling platform to achieve and combine topological superconductivity with existing and novel qubit modalities. Here we demonstrate a qu...

Quantum dot light-emitting diodes (QD-LEDs) are one of the most promising self-emissive displays in terms of light-emitting efficiency, wavelength tunability, and cost. Future applications using QD-LEDs can cover a range from a wide color gamut and large panel displays to augmented/virtual reality displays, wearable/flexible displays, automotive displays, and transparent displays, which demand extreme performance in terms of contrast ratio, viewing angle, response time, and power consumption. The efficiency and lifetime have been improved by tailoring the QD structures and optimizing the charg...

We consider adiabatic quantum pumping through a resonant level model, a single-level quantum dot connected to two fermionic leads. Using the tools of adiabatic expansion, we develop a self-contained thermodynamic description of this model accounting for the variation of the energy level of the dot and the tunnelling rates with the thermal baths. This enables us to study various examples of pumping cycles computing the relevant thermodynamic quantities, such as the entropy produced and the dissipated power. These quantities are compared with the transport properties of the system, i.e. the pump...

Major advances in the exploration of CDots are highlighted for their serving as high-performance yet nontoxic fluorescence probes for one- and multi-photon bioimaging in vitro and in vivo, and for their uniquely potent antimicrobial function to inactivate effectively and efficiently some of the toughest bacterial pathogens and viruses under visible/natural or ambient light conditions.

A structure comprising a quantum dot is obtained by the method according to one of claims 1-6, wherein the quantumdot includes a layer of amphiphilic polymer disposed on the surface the quantum dot.

Embodiments of the invention provide such a manufacturing method, the quantum dot of the quantum dot.

FIELD: nanotechnology. SUBSTANCE: invention relates to nanotechnology. The method for production of a quantum dot comprises the following steps: a) mixing an amphiphilic polymer dissolved in a non-coordinating solvent with a first precursor for obtaining a carboxylate precursor; b) mixing the carboxylate precursor with the second precursor to obtain the quantum dot core; c) mixing the quantum dot core with the precursor selected from the group consisting of: a third precursor, a fourth precursor and their combination to obtain a coating of the quantum dot on the quantum dot core to form the qu...

Overall, the studies indicated that GQDs and N-GQDs hold prospect as a framework for further development of neuroactive compounds for relevant central nervous system (CNS) purposes.

Quantum‐dot light‐emitting diodes (QLEDs) have been considered the next‐generation display. However, the toxicity of Cd or Pb in these quantum dots (QDs) and the low performance of blue QLEDs remain critical issues, which greatly limit their sustainable development. Herein, first blue‐emitting quantum‐dot light‐emitting diode based on orthorhombic BN QDs with high photoluminescence quantum yield (PLQY) of 31.3% and electroluminescence at 437 nm is reported. With optimal solvothermal parameters, high photoluminescence quantum yield (PLQY) of 31.3% can be realized in the as‐synthesized BN QDs. T...

Abstract. Epitaxial quantum dots formed by III–V compound semiconductors are excellent sources of non-classical photons, creating single photons and entangled multi-photon states on demand. Their semiconductor nature allows for a straightforward combination with mature integrated photonic technologies, leading to novel functional devices at the single-photon level. Integrating a quantum dot into a carefully engineered photonic cavity enables control of the radiative decay rate using the Purcell effect and the realization of photon–photon nonlinear gates. In this review, we introduce the basis ...

This review is focusing on various pharmaceutical applications of quantum dots, which have specific functional groups, have charges over their surface, and are extremely small in size, which makes them more permeable through tight junctions.

Violet phosphorus is another promising layered semiconducting elemental structure for electronic and optoelectronic applications. Violet phosphorus quantum dots (VPQDs) have unique optical and electronic properties due to quantum mechanics. However,...

The 2023 Nobel Prize in Chemistry was awarded to Alexei Ekimov, Louis Brus, and Moungi Bawendi for the discovery and development of quantum dots, an area of research ripe with exciting results in terms of both fundamental science and present and forthcoming applications. Quantum dots, with their colors and their intriguing properties, have fascinated and engaged generations of scientists over the last 40 years, including myself. I present here a brief historical perspective of the field, from my personal standpoint and with insights from my own career, along with an outlook on what I believe w...

The engineering concerning surface ligands, additives, and hybrid composition for PQ DSCs is outlined first, followed by analyzing the reasons of undesired performance of PQDSCs and some challenges and perspectives concerning PQDs are discussed.

Carbon quantum dots (CQDs) are a new blooming carbon containing nanoparticles having size of less than 10 nm. They have wide range of application in the field of sensing of inorganic analytes, bio sensing, cell imaging, studying biological processes in living cells and also for drug delivery. These nanoparticles of carbon are playing important roles due to their interesting qualities like small particle size, biocompatibility, fluorescing, etc. Sometimes it shows excitation wavelength dependent, which may be more than 100 nm, and sometimes excitation wavelength independent fluorescent property...

Carbon quantum dots are a novel form of carbon material. They offer numerous benefits including particle size adjustability, light resistance, ease of functionalization, low toxicity, excellent biocompatibility, and high-water solubility, as well as their easy accessibility of raw materials. Carbon quantum dots have been widely used in various fields. The preparation methods employed are predominantly top-down methods such as arc discharge, laser ablation, electrochemical and chemical oxidation, as well as bottom-up methods such as templates, microwave, and hydrothermal techniques. This articl...

To obtain the quantum dot having a novel structure. The method of manufacturing a quantum dot, in a solvent in the step of dispersing the nano oxide particles are exposed to the predetermined crystal plane in the solvent, the crystal plane of the nanosheet particles, a step of growing a semiconductor layer.

Coupling of atoms is the basis of chemistry, yielding the beauty and richness of molecules. We utilize semiconductor nanocrystals as artificial atoms to form nanocrystal molecules that are structurally and electronically coupled. CdSe/CdS core/shell nanocrystals are linked to form dimers which are then fused via constrained oriented attachment. The possible nanocrystal facets in which such fusion takes place are analyzed. Coherent coupling is manifested by a red shift of the band gap, in agreement with quantum mechanical simulations. Single nanoparticle spectroscopy unravels the attributes of ...

Fast, efficient, and low power modulation of light at microwave frequencies is crucial for chip-scale classical and quantum processing as well as for long-range networks of superconducting quantum processors. A successful approach to bridge the gap between microwave and optical photons has been to use intermediate platforms such as acoustic waves, which can couple efficiently to a variety of quantum systems. Here, we use gigahertz-frequency focusing surface acoustic wave cavities on GaAs that are piezo-electrically coupled to superconducting circuits and parametrically coupled, via strain, to ...

This mini-review aims to provide a better understanding of the current standing in the research of quantum dots, point out some knowledge gaps in the field, and provide hints for potential future research.

Summary: Spin qubits in semiconductor quantum dots represent a prominent family of solid-state qubits in the effort to build a quantum computer. They are formed when electrons or holes are confined in a static potential well in a semiconductor, giving them a quantized energy spectrum. The simplest spin qubit is a single electron spin located in a quantum dot, but many additional varieties have been developed, some containing multiple spins in multiple quantum dots, each of which has different benefits and drawbacks. While these spins act as simple quantum systems in many ways, they also experience...

In this paper, we reviewed the recent literature on quantum dot lasers. First, we started with the physics of quantum dots. These nanostructures provide limitless opportunities to create new technologies. To understand the applications of quantum dots, we talked about the quantum confinement effect versus dimensionality and different fabrication techniques of quantum dots. Secondly, we examined the physical properties of quantum dot lasers along with the history and development of quantum dot laser technology and different kinds of quantum dot lasers compared with other types of lasers. Thirdl...

In the last decade, a lot of effort have gone to find the most appropriate physical implementation of quantum computer. Quantum dot based system is one of the most promising system owing to its integrability with classical computation hardware and its versatility in realizing qubits and quantum gates. In this work, we propose a model for quantum dot based realization of qubits and quantum gates. The proposed system makes use of semiconductor hetrostructure based quantum dots and gate voltages to confine electrons and thus defining the qubits. Electron spin resonance is used to manipulate the s...

The recent advancements in the top-down and bottom-up approaches for the synthesis of GQDs are reviewed and a detailed review of the various surface properties of GQDs and their applications in bioimaging and biosensing is presented.

Semiconducting quantum dots (QDs) have received huge attention for energy conversion and storage due to their unique characteristics, such as quantum size effect, multiple exciton generation effect, large surface‐to‐volume ratio, high density of active sites, and so on. However, the holistic and systematic understanding of the energy conversion and storage mechanism centering on QDs in specific application is still lacking. Herein, a comprehensive introduction of these extraordinary 0D materials, e.g., metal oxide, metal dichalcogenide, metal halides, multinary oxides, and nonmetal QDs, is pre...

This work experimentally demonstrates how varying the pump power and spectral detuning with respect to the excitonic transition can improve quantum-secured communication rates and provide stable emission statistics regardless of network-environment fluctuations.

This work studies the behavior of four quantum dots in a suspended carbon nanotube and finds that the system presents a transition from the Mott insulating state to a polaronic state, with the appearance of pairing correlations and the breaking of the translational symmetry.

This Perspective discusses the advances of employing QDs for visible-light-driven organic transformations categorized into net reductive reactions, net oxidative reactions, and redox neutral reactions and provides the outlook for potential future directions in the field.

Quantum dots (QDs) are very small nanoparticles and are composed of hundreds to thousands of atoms. These semiconducting materials can be made from an element, such as silicon or germanium, or compounds such as cadmium sulphide (CdS) or cadmium selenide (CdSe). The colour of these small particles does not depend on the type of semiconducting material from which the dots are made, but rather on its diameter. Besides, ODs attract the most attention because of their unique visual properties. Therefore, these are used in all kinds of applications where precise control of coloured light is importan...