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Colloidal quantum dots (QDs) are promising building blocks in optoelectronic devices, mainly due to their size/shape/composition‐tunable properties. Core–shell QDs, in particular, offer enhanced stability, mitigated photoluminescence blinking, and suppressed non‐radiative recombination compared to plain QDs, making them highly promising for energy conversion applications such as photovoltaic devices, luminescent solar concentrators, solar‐driven hydrogen production, and light‐emitting diodes. Here, a comprehensive analysis of core–shell QDs in energy conversion technologies is provided. Emerging design strategies are explored and various synthetic methods focusing on optimizing band structure, band alignment, and optical properties are critically explored. Insights into the structure‐property relationship are discussed, highlighting recent advancements and the most effective strategies to enhance energy conversion performance. The review is concluded by addressing key challenges and proposing future research directions, emphasizing the need for rational design, precise synthesis, effective surface engineering, and the integration of machine learning to achieve optimized properties for technological applications. [ABSTRACT FROM AUTHOR]

In this study, ZnO quantum dots (ZnO@QDs) were synthesized and functionalized with 2nd generation poly amido amine (2GPD) using 3-amino-propyl tri-methoxy silane as the initiator core, facilitated by tetramethylammonium hydroxide (TMAH) to enhance stability against oleate coating. Concurrently, a mesoporous substrate with a unique morphology was developed as a drug reservoir for doxorubicin loading. ZnO quantum dots displayed photoluminescence radiation, with dimensions ranging from 5 to 7 nm and exhibiting spherical morphology. The cubic structure of the synthesized mesoporous nanocatalysts was also confirmed. Brunauer-Emmett-Teller analysis indicated a multidimensional porous structure of the nanocarriers, while zeta potential analysis showed a stable system (approximately −9.6 mV). Fourier transform infrared spectroscopy, X-ray diffraction, and energy dispersive spectroscopy corroborated these findings. Drug release studies demonstrated sustained release under acidic conditions (pH 5.5), with an efficiency of approximately 94 %. These results highlight the potential applications of this nanosystem for controlled drug delivery, underscoring its practical implications in the field of nanotechnology. [ABSTRACT FROM AUTHOR]

Short‐wave infrared (SWIR) photodetectors utilizing quantum dot (QD) material systems, harnessed through the quantum confinement effect to tune the absorption wavelength, offer an attractive avenue for the development of cost‐effective and solution‐processed photodetectors compared to the relatively expensive compound semiconductor photodetectors. However, the pores between the QDs and poor chemical stability after surface modification have impeded the practical application of quantum‐dot‐based photodetectors. In this study, high‐gain SWIR photodetector is demonstrated and achieved by incorporating PbS QD into the Cs2AgBiBr6 halide‐based double perovskite matrix, as confirmed by X‐ray diffraction, transmission electron microscope, and energy dispersive spectrometer. The thin film structure and detailed local structure are revealed by 2D grazing‐incidence wide and small‐angle X‐ray scattering. The resulting PbS@Cs2AgBiBr6‐based SWIR photodetector exhibits remarkable performance with a responsivity and detectivity of 15000 A W−1 and 1.31 × 1012 cm Hz1/2 W−1, respectively. This study offers valuable insights into the design of composite materials for high‐gain SWIR photodetectors. [ABSTRACT FROM AUTHOR]

Protein aggregation is associated with various diseases caused by protein misfolding. Among them, amylin deposition is a prominent feature of type 2 diabetes. At present, the mechanism of amylin aggregation remains unclear, and this has hindered the treatment of type 2 diabetes. In this study, we analyzed the aggregation process of amylin using the quantum dot (QD) imaging method. QD fluorescence imaging revealed that in the presence of 100 μM amylin, aggregates appeared after 12 h of incubation, while a large number of aggregates formed after 24 h of incubation, with a standard deviation (SD) value of 5.435. In contrast, 50 μM amylin did not induce the formation of aggregates after 12 h of incubation, although a large number of aggregates were observed after 24 h of incubation, with an SD value of 2.883. Confocal laser microscopy observations revealed that these aggregates were deposited in three dimensions. Transmission electron microscopy revealed that amylin existed as misfolded fibrils in vitro and that QDs were uniformly bound to the amylin fibrils. In addition, using a microliter-scale high-throughput screening (MSHTS) system, we found that rosmarinic acid, a polyphenol, inhibited amylin aggregation at a half-maximal effective concentration of 852.8 μM. These results demonstrate that the MSHTS system is a powerful tool for evaluating the inhibitory activity of amylin aggregation. Our findings will contribute to the understanding of the pathogenesis of amylin-related diseases and the discovery of compounds that may be useful in the treatment and prevention of these diseases. [ABSTRACT FROM AUTHOR]

There is increasing interest in the use of cannabidiol (CBD) as a potential therapeutic for alleviating chronic pain in cancer patients. Reliable determination of CBD content tailored to individual patients is essential for effective administration. Additionally, there is a growing need for rapid and portable detection methods for food products containing trace amounts of cannabis-derived compounds. Electrochemical technique offer a promising approach for fast and straightforward analytical identification of compounds like CBD. This study presents the fabrication of electrochemical sensor utilizing Fe2O3 quantum dots (QDs) – Co3O4 nanowires (NWs) as a sensing layer in a modified silver electrode. Chemical and structural analyses including energy-dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET) analysis, and X-ray photoelectron spectroscopy (XPS) confirm the excellent decoration of Fe2O3 QDs on the Co3O4 NW surfaces. The Fe2O3 QDs-Co3O4 NWs exhibit electrochemical activity based on cyclic voltammetry (CV), chronoamperometry (CA), and differential pulse voltammetry (DPV) measurements. The sensor demonstrates a sensitivity of 1.21 mA•mM⁻¹•mm⁻¹ with strong linearity over the range of 0.02–0.1 mM (R2 = 0.9991) and a low detection limit of 0.67 µM. The enhanced electrochemical response of the Fe2O3 QDs-Co3O4 NWs sensing layer is attributed to the increased number of active sites resulting from the heterostructure formed by the two semiconductor crystals. A charge-transfer mechanism driven by stochastic processes is proposed to explain the electrochemical sensing behavior. [ABSTRACT FROM AUTHOR]

Memristor devices for resistive-switching memory and artificial synapses have emerged as promising solutions for overcoming the technological challenges associated with the von Neumann bottleneck. Recently, due to their unique optoelectronic properties, solution processability, fast switching speeds, and low operating voltages, quantum dots (QDs) have drawn substantial research attention as candidate materials for memristors and artificial synapses. This review covers recent advancements in QD-based resistive random-access memory (RRAM) for resistive memory devices and artificial synapses. Following a brief introduction to QDs, the fundamental principles of the switching mechanism in RRAM are introduced. Then, the RRAM materials, synthesis techniques, and device performance are summarized for a relative comparison of RRAM materials. Finally, we introduce QD-based RRAM and discuss the challenges associated with its implementation in memristors and artificial synapses. [ABSTRACT FROM AUTHOR]

Despite the existing effective treatment methods, tuberculosis (TB) is the second most deadly infectious disease, its carriers in the latent and active phases accounting for more than 20% of the world population. An effective method for controlling TB and reducing TB mortality is regular population screening aimed at diagnosing the latent form of TB and taking preventive and curative measures. Numerous methods allow diagnosing TB by directly detecting Mycobacterium tuberculosis (M.tb) biomarkers, including M.tb DNA, proteins, and specific metabolites or antibodies produced by the host immune system in response to M.tb. PCR, ELISA, immunofluorescence and immunochemical analyses, flow cytometry, and other methods allow the detection of M.tb biomarkers or the host immune response to M.tb by recording the optical signal from fluorescent or colorimetric dyes that are components of the diagnostic systems. Current research in biosensors is aimed at increasing the sensitivity of detection, a promising approach being the use of fluorescent quantum dots as brighter and more photostable optical tags. Here, we review current methods for the detection of M.tb biomarkers using quantum dot-based nanosensors and summarize data on the M.tb biomarkers whose detection can be made considerably more sensitive by using these sensors. [ABSTRACT FROM AUTHOR]

High‐performance 0D–2D hybrid photodetectors integrated with a crosslinker for direct pattering of quantum dots on the large‐scale synthesized MoS2 layer are reported. In the patterned hybrid structure, QD layers are patterned with a resolution of up to 2 µm, ensuring high precision. Enhanced charge transfer from QDs to 2D materials is confirmed using PL quenching, TR‐PL, and UPS analysis. As a result, the QD/2D hybrid photodetectors with crosslinker‐assisted direct patterning demonstrated a remarkable photoresponsivity of ≈105 A W−1 and a specific detectivity of over 1011 Jones, attributed to the difference in built‐in potential. The crosslinker patterning of QDs opens up potential applications for the photodetectors in highly integrated image sensors and can be further extended to high‐resolution display industries, eliminating unnecessary fabrication processes. [ABSTRACT FROM AUTHOR]

Quantum dot (QD) color conversion films encapsulated with high barrier films are being applied to wide color gamut liquid crystal displays (LCDs). However, besides the expensive cost of barrier films, the aging of QD films under high temperature and high‐intensity blue light remains unresolved. Here, a QD color conversion film is developed using phase‐change liquid encapsulation suitable for roll‐to‐roll film fabrication. In this method, the QDs are encapsulated in the phase‐change material octadecane, which switches between solid and liquid states in response to temperature changes corresponding to standby and operation of the display, respectively. This process endows the self‐healing of QD ligands (liquid state) and effectively increases the lifespan of QDs under ultraviolet (UV) light. This novel phase‐change liquid encapsulation method significantly improves the UV light resistance and long‐term stability of QD color conversion films compared to conventional solid‐state encapsulation. Under conditions of 60 °C, 90% humidity, and 40 mW cm−2 blue LED backlighting, the phase‐change liquid encapsulated QD color conversion film maintains less than 10% brightness degradation for 680 h. This phase‐change liquid encapsulation technology opens new possibilities for manufacturing more durable QD color conversion films. [ABSTRACT FROM AUTHOR]

The utilization of perovskite quantum dots (PQDs) in photoelectric devices is indeed an area of intense research due to their advantageous properties such as tunability of visible light and efficient light emission. In this study, mixed CsPbI 3 and FAPbI 3 PQD dispersions were successfully employed for cation exchange to prepare red-color Cs 1−x FA x PbI 3 PQD with the photoluminescence (PL) wavelength from 689 nm (x = 0) to 778 nm (x = 1). It is also found that the aggregation of Cs 1−x FA x PbI 3 PQD films were strongly dependent on x. When x from 0 to 0.6, the holes in PQD thin films were gradually improved. On the opposite, when x > 0.6, the PQDs thin films returned more and more holes due to an excess of FA + cations. The resulting Cs 1-x FA x PbI 3 PQD based light-emitting diodes (LEDs) also demonstrated tunable emission wavelengths, and it is worth mentioning that the maximum external quantum efficiency (EQE) of 11.22 % was achieved with an emission wavelength of 758 nm when x = 0.6. [ABSTRACT FROM AUTHOR]

Quantum emissions, such as single photon emission (SPE) and superradiance (SR), are fundamental ingredients of quantum optical technology. The quest for efficient, controllable, and scalable quantum emitters is crucial for successfully implementing various quantum technologies, such as quantum computing, secure quantum communication and high-precision metrology. Recently, perovskite quantum dots (PQDs) have emerged as highly efficient sources of quantum emission due to their excellent optical properties, including near 100% quantum yield, high optical absorbance, and tunable bandgaps covering the entire visible range. This Prospective introduces the principles of quantum emissions, including SPE and SR, and summarizes recent progress in exploring quantum emissions in PQDs. We focus on the prospects, advantages, and challenges associated with the quantum emissions from PQDs. This Prospective concludes with an outlook on PQDs in advancing future quantum technologies. [ABSTRACT FROM AUTHOR]

We propose a theoretical model for the single photon quantum router that consists of two plasmonic waveguides, one of which is infinite and the other is semi-infinite, coupled to two two-level quantum dots (QDs) with dipole–dipole interaction (DDI). The infinite waveguide, the main branch, couples with both QDs, and the semi-infinite, the side branch, couples with the main branch at the position of one of the QDs. In such a system the incident single photon can also be transferred to the side branch, not only be transmitted or reflected. The results show that the transfer rate mainly depends on the coupling strength between the QDs and the two waveguides, but there exists a certain limit in the increase of the transfer rate. The DDI between the QDs gives a remarkable change to the routing spectra and the routing properties are different according to the position of the side branch. The proposed system is indeed multi-channel single photon quantum router, which has more practical significance than the one-dimensional router and can be employed in multi-user quantum networking. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks (COFs) with stable crystalline porous structures and flexible assembly properties contribute to the direct photocatalytic synthesis of H2O2 to meet the growing global demand. To address the challenges of insufficient redox capacity and photogenerated carrier recombination of COFs, S‐scheme heterojunction is constructed from COFs with quantum dots (QDs) to improve the photocatalytic production of H2O2. Herein, 0D ZnCdS QDs (ZCS) uniformly anchor on the surface of a 2D conjugated tetrathiafulvalene‐based COF (TT‐COF), affording the S‐scheme heterojunction TT‐COF/ZCS. Formation of S‐scheme heterojunction effectively prevents the agglomeration of ZCS, modulates the energy band structure of TT‐COF, and enhances the migration of photogenerated carriers and redox ability. As a total consequence, the optimized heterojunction (TZ‐40) is able to afford H2O2 in the yield up to 5171 µmol g−1 h−1 under visible light irradiation with H2O and O2, much higher than those for TT‐COF, 2520 µmol g−1 h−1, and ZCS, 2647 µmol g−1 h−1. The present result demonstrates the great potential of COFs/QDs‐based S‐scheme heterojunctions for photocatalytic applications including photocatalytic H2O2 production. [ABSTRACT FROM AUTHOR]

Photosensitive quantum dot light‐emitting diodes (PSQLEDs) possess the dual capabilities of generating and detecting light signals, which is of significant importance for the development of miniaturized and integrated optoelectronic devices. However, the state‐of‐the‐art PSQLEDs can only detect light signals within a certain wavelength range, and require switching between the two functions under different bias voltage directions. In this work, The use of a ZnO/quantum dots (QDs)/ZnO multilayer (ZQZ ML) architecture as both the electron transport layer and the photosensitive layer is pioneered. The QDs in this structure are composed of narrow‐bandgap lead sulfide QDs and wide‐bandgap cadmium selenide QDs, successfully realizing a unique PSQLED device with C photosensitive characteristics. As a result, the as‐fabricated device can respond to illumination from 365 to 1300 nm, and the device achieves a photoresponse rate of 20.9 mA W−1 in self‐powered mode to UV light. After UV light irradiation, the maximum external quantum efficiency and maximum luminance of device reached 11.8% and 64,549 cd m−2, respectively. The device shows a record‐high luminance ON/OFF ratio of 5500%, which is beneficial for high contrast and accurate information display. [ABSTRACT FROM AUTHOR]

Gain medium‐doped active optical fibers for optical amplification and long‐range transmission have triggered a lot of researches. Traditional rare‐earth ion‐doped active fibers have non‐adjustable emissions, narrow band luminescence, limited gain enhancement, and other challenges. The unique optical properties of quantum dots (QDs) can further improve the doped optical fibers in the light amplification capacity, temperature sensitivity and to gain a broad‐spectrum coverage and lower laser threshold and other superiorities. However, there are few systematic discussions on the development of the technologies and applications of those QD‐doped optical fibers. In this review, the optical properties, temperature characteristics and optical amplification mechanisms of QD‐doped optical fibers are outlined. Then, the preparation technologies and the applications of QD‐doped optical fibers are highlighted. Additionally, the existing challenges and future development prospects of QD‐doped optical fibers are discussed. [ABSTRACT FROM AUTHOR]

The paper considers an algorithm for entangling the states of an exciton qubit on a single quantum dot and a charge qubit on a double quantum dot. The possibility of performing a conditional two-qubit CNOT operation using laser transitions and the Förster effect is analyzed. Estimates of the system parameters are given for which this operation is implemented with a probability close to unity. [ABSTRACT FROM AUTHOR]

The aim of this work is to study the optical properties of ZnSe/ZnS non-concentric core–shell quantum dots (CSQDs). The numerical method used in this work is based on a combination of coordinate transformation and finite difference method (FDM) to solve the three dimensions of the Schrödinger equation. The optical properties are obtained using the compact density matrix formalism. The influence of different dimensions of the non-concentric CSQD, the position of a core material and the effect of different values of the incident optical intensity I on the optical properties of the CSQD are investigated. The results obtained indicate that the oscillator strength, absorption coefficient and refractive index changes are strongly dependent on the size of the CSQD. The magnitude of both the total absorption coefficient and the refractive index decreased as the incident optical intensity increased. In addition, the resonance peaks for the absorption coefficient and refractive index changes shift towards higher energies when we move from concentric to non-concentric core–shell quantum dots. [ABSTRACT FROM AUTHOR]

The long-lived green luminescence of human bone (that has been heated to 600 °C for a short duration) is attributed to a carbon quantum dot material (derived from collagen) encapsulated and protected by an inorganic matrix (derived from bone apatite) and is more intense in dense rigid and crystalline parts of (healthy) human bones. The strong collagen-apatite interaction results (upon decomposition) in a protective inorganic environment of the luminescent centers allowing long-lived triplet-based emission of a carbon (quantum) dot-like material at room temperature, as well as resilience against oxidation between 550 and 650 °C. The graphitic black phase (obtained upon heating around 400 °C) is a precursor to the luminescent carbon-based material, that is strongly interacting with the crystalline inorganic matrix. Human bone samples that have been heated to 600 °C were subjected to steady-state and time-resolved spectroscopy. Excitation-emission matrix (EEM) luminescence spectroscopy revealed a broad range of excitation and emission wavelengths, indicating a heterogeneous system with a broad density of emissive states. The effect of low temperature on the heat-treated bone was studied with Cryogenic Steady State Luminescence Spectroscopy. Cooling the bone to 80 K leads to a slight increase in total emission intensity as well as an intensity increase towards to red part of the spectrum, incompatible with a defect state model displaying luminescent charge recombination in the inorganic matrix. Time-resolved spectroscopy with an Optical Multichannel Analyzer (OMA) and Time Correlated Single Photon Counting (TCSPC) of these samples showed that the decay could be fitted with a multi-exponential decay model as well as with second-order decay kinetics. Confocal Microscopy revealed distinct (plywood type) structures in the bone and high intensity—fast decay areas as well as a spatially heterogeneous distribution of green and (fewer) red emissive species. The use of the ATTO 565 dye aided in bone-structure visualization by chemical adsorption. Conceptually our data interpretation corresponds to previous reports from the material science field on luminescent powders. [ABSTRACT FROM AUTHOR]

Recent advancements in quantum photonic circuits have significantly influenced the field of quantum information processing. The pursuit of an integrated quantum photonic circuit that offers an active, stable platform for large-scale integration and high processing efficiency remains a key objective. The grating coupler, as a crucial element for an efficient transformation output interface in the integrated quantum photonic circuits, presents significant potential for practical applications. Here, we demonstrate the integration block of a highly efficient shallow-etched focusing apodized grating coupler with indium arsenide (InAs) quantum dots (QDs) in gallium arsenide (GaAs) on a SiO2 substrate for active quantum photonic circuits. The designed grating couplers possess a high efficiency over 90% in the broadband (900–930 nm) from the circuit to free space, and a nearly-perfect match with the fiber mode. Experimentally, the efficiency to free space reaches 81.8%, and the match degree with the fiber mode is high up to 92.1%. The proposed integration block offers the potential for large-scale integration of active quantum photonic circuits due to its stable solid substrate and highly performant output for quantum measurements. [ABSTRACT FROM AUTHOR]

Early and accurate diagnosis of glaucoma is crucial to prevent the progressive deterioration that leads to irreversible vision loss. It is imperative to develop an effective screening tool for glaucoma. Ciliary neurotrophic factor (CNTF) is a tear biomarker implicated in glaucoma pathogenesis. Lateral flow assay (LFA) provides an ideal platform for detection of glaucoma in tear fluid. A quantum dot‐based fluorescence LFA, integrated with a 3D printed readout box, is developed for fast (30 min), sensitive, and quantitative CNTF detection in tears. A standard curve is firstly generated for the quantitative detection of CNTF. The limit of detection (LOD) of the obtained LFA strip at 6.45 pg·mL−1 is comparable to that of the enzyme‐linked immunosorbent assay (ELISA) at 6.42 pg·mL−1. This enables the identification of low CNTF levels (25.7 ± 14.9 pg·mL−1) reported in tear fluid from glaucoma patients. This LFA is found to be highly selective for CNTF and maintained consistent results in different pH condition. The strip remaines stablewhen stored in the darkat room temperature. A smartphone app is developed to simplify analysis and enable prompt and easily obtainable results. This method shows great potential to be a powerful tool for point‐of‐care glaucoma screening. [ABSTRACT FROM AUTHOR]

We consider a theoretical model of a quantum node that implements a two-qubit controlled-NOT (CNOT) operation on photonic qubits with spatial encoding. Each of the qubits is represented by a pair of modes that support an arbitrary superposition of single-photon states. The active element of the node is a single or double quantum dot (QD) with a tunable frequency, coherently exchanging an energy quantum with the modes. The spectral characteristics of the elements of the quantum node are simulated. The probability of performing a controlled inversion of the qubit state is calculated, depending on the system parameters. [ABSTRACT FROM AUTHOR]

CdS quantum dots (CdS QDs) are regarded as a promising photocatalyst due to their remarkable response to visible light and suitable placement of conduction bands and valence bands. However, the problem of photocorrosion severely restricts their application. Herein, the CdS QDs-Co9S8 hollow nanotube composite photocatalyst has been successfully prepared by loading Co9S8 nanotubes onto CdS QDs through an electrostatic self-assembly method. The experimental results show that the introduction of Co9S8 cocatalyst can form a stable structure with CdS QDs, and can effectively avoid the photocorrosion of CdS QDs. Compared with blank CdS QDs, the CdS QDs-Co9S8 composite exhibits obviously better photocatalytic hydrogen evolution performance. In particular, CdS QDs loaded with 30% Co9S8 (CdS QDs-30%Co9S8) demonstrate the best photocatalytic performance, and the H2 production rate reaches 9642.7 μmol·g−1·h−1, which is 60.3 times that of the blank CdS QDs. A series of characterizations confirm that the growth of CdS QDs on Co9S8 nanotubes effectively facilitates the separation and migration of photogenerated carriers, thereby improving the photocatalytic hydrogen production properties of the composite. We expect that this work will facilitate the rational design of CdS-based photocatalysts, thereby enabling the development of more low-cost, high-efficiency and high-stability composites for photocatalysis. [ABSTRACT FROM AUTHOR]

We theoretically study the polarization of plasmonic fields in a hybrid nanosystem composed of three different metallic nano ellipsoid and a semiconductor quantum dot. The components of the hybrid nanosystem interact with three electromagnetic fields and one another via dipole-dipole interactions. We derive the density matrix equations at a steady state for the description of the optical properties of the hybrid nanosystem. The polarization of the plasmonic fields induced on the prolate, spherical, and oblate nano ellipsoid is calculated. We find that the polarization of the plasmonic fields depends on the number of the metallic nanoparticles (ellipsoid), the depolarization factor of the metallic nano ellipsoid, the direction of the plasmonic field, and the metallic nano ellipsoid parameters of the hybrid nanosystem. The phenomena of electromagnetically induced transparency (EIT) and electromagnetically induced transparency with amplification (EITA) are obtained in this work. [ABSTRACT FROM AUTHOR]

Equations are obtained for the quantum distribution functions over discrete states in systems of non-interacting fermions and bosons with an arbitrary, including small, number of particles. The case of systems with two levels is considered in detail. The temperature dependences of entropy, heat capacities and pressure in two-level Fermi and Bose systems are calculated for various multiplicities of degeneracy of levels. [ABSTRACT FROM AUTHOR]

Present work inspects the role of spatial impurity spread (SIS) on oscillator strength (OS) and two nonlinear optical (NLO) properties of GaAs quantum dot (QD) containing impurity. The NLO properties include total optical absorption coefficient (TOAC) and the total optical refractive index change (TORIC). The said properties are studied under the influence of Gaussian white noise (GWN) that has been applied to the doped QD by means of additive and multiplicative routes. The study manifests the delicate interplay between noise and SIS that finally designs the NLO properties. TOAC and TORIC reveal red-shift as SIS enhances both with and without noise. OS, however, shows steady fall with enhancement of SIS. The study also indicates plausible ways of attaining very large NLO response by applying GWN in a particular pathway. Depending upon the application of noise and its route of introduction, the OS and the NLO properties can either be depleted or amplified to different extents in comparison with the noise-free situation. [ABSTRACT FROM AUTHOR]

We study the absorption coefficient of a diluted magnetic semiconductor ellipsoidal quantum dot with Rashba spin–orbit coupling. The Schrödinger equation for a one-electron ellipsoidal quantum dot was solved within the framework of the effective mass approximation method. The wave vector and electron energy found during the solution were used to find an expression for the absorption coefficient. The article examines intraband optical transitions relative to changes in external parameters. The decrease in the absorption coefficient as a function of the energy of the incident photon was studied at different values of the magnetic field, the Rashba parameter, temperature, concentration of Mn atoms and the radius of the ellipsoid. According to the results obtained, these parameters significantly affect intraband optical transitions. [ABSTRACT FROM AUTHOR]

The rapid development of emerging technologies observed in recent years, such as artificial intelligence, machine learning, mobile internet, big data, cloud computing, and the Internet of Everything, are generating escalating demands for expanding the capacity density, and speed in next‐generation optical communications. This poses a significant challenge to existing communication techniques. Within this context, the integration of near‐infrared broadband, tunable, and high‐gain luminescent materials into silicon optical circuits or fiber architectures to transmit and modulate light shows enormous potential for advancing next‐generation communication techniques. Here, this review provides an overview of the recent breakthroughs in near‐infrared luminescent epitaxial/colloidal quantum dots, and metal‐active‐center‐doped materials for broadband optical amplifiers and tunable lasers. We also expound on efforts to enhance the bandwidth and gain of these materials‐based amplifiers and lasers, exploring the challenges associate with developing ultra‐broadband and high‐speed optical communication systems. Additionally, the potential applications in Fifth Generation Fixed Networks, integration with 5G and 6G wireless networks, compensation for current Si electronic based CMOS for high computing capability, and the prospects of these light sources for next‐generation optoelectronic devices are discussed. [ABSTRACT FROM AUTHOR]

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In this work, we study the energy levels of electrons and holes of InAs quantum dots inside InP/InAs 0.25 P 0.75 /InP semiconductor nanowires. Taking into account the nonparabolicity of the dispersion law, the energy levels are calculated in two different ways. The change in the energy levels of a quantum dot at different positions inside a quantum nanowire is considered. The energy levels of semiconductor nanowire of various sizes are studied at a constant size. Changes in the energy levels of a quantum nanodot of a cubic shape are found when its size changes from 5 to 25 nm, located inside a quantum nanowire with a square section of 25 × 25 nm. [ABSTRACT FROM AUTHOR]

The interplay between superconductivity and the Kondo effect has stimulated significant interest in condensed matter physics. They compete when their critical temperatures are close and can give rise to a quantum phase transition that can mimic Majorana zero modes. Here, we have fabricated and measured Al-InSb nanowire quantum dot-Al devices. In the Kondo regime, a supercurrent-induced zero-bias conductance peak emerges. This zero-bias peak shows an anomalous negative magnetoresistance (NMR) at weak magnetic fields. We attribute this anomalous NMR to quasiparticle trapping at vortices in the superconductor leads as a weak magnetic field is applied. The trapping effect lowers the quasiparticle-caused dissipation and thus enhances the Josephson current. This work connects the vortex physics and the supercurrent tunneling in Kondo regimes and can help further understand the physics of Josephson quantum dot system. [ABSTRACT FROM AUTHOR]

Traditional quantum dot-based lateral flow immunoassay (QD-LFIA) is limited to signal loss in part by the blinking, photobleaching and oxidative quenching of QD probes. Inspired by the good application of silver deposition on QD surfaces in tissue imaging, and in the context of improving the assay performance without compromising the simplicity and practicality, we report that introducing the QD-silver combination to the LFIA system, has the advantages of accuracy improvement, signal enhancement and user friendliness promotion, but maintains the cost-effective property and commercial accessibility of QD-LFIA. The effect was shown by using CdSe/ZnS QD-LFIA coupled with anti-sodium pentachlorophenate antibody, which provided a 4-fold improvement in the signal, a 2.5-fold improvement in the detection limit and a zero false-negative rate for sodium pentachlorophenate analysis in chicken samples. The proposed LFIA integrates the possibilities of colorimetric and fluorometric detection with different detection limits (fluorometric at 10 ng/mL and colorimetric at 4 ng/mL) and with acceptable detection times (fluorometric at 12 min and colorimetric at 27 min). The current results indicate that this QD-silver combined LFIA is complementary to conventional fluorescence LFIA and could be an inexpensive, versatile, and sensitive alternative.

Copper indium selenide (CISe) is a prototype infrared semiconductor with low toxicity and unique optical characteristics. Its quantum dots (QDs) accommodate ample intrinsic point defects which may actively participate in their rather complex photophysical processes. We synthesize CISe QDs with similar sizes but with distinct highly stoichiometry-deviating atomic ratios. The synthesis condition employing Se-rich precursors yields the Cu-deficient CISe QDs with special photophysical properties. The photoluminescence exhibits monotonic red shift from 680 to 775 nm when the ratio of Cu's proportion to In's decreases. The luminescence is found to stem from the copper vacancy and antisite defects. The CISe QDs exhibit Raman activity at 5.6, 6.9, and 8.7 THz that is separately assigned to Cu–Se and In–Se optical phonon modes and surface mode. [ABSTRACT FROM AUTHOR]

The researches of the spatial redistribution of defects of interstitial Cd in the CdSe quantum dot with a shell and the quantum dot – human serum albumin bionanocomplexes were carried out. On the basis of the developed deformation-diffusion model, the method of "deformation-diffusion retraction" is proposed, which will limit the migration of cadmium beyond the QD boundaries and significantly reduce their toxicity for living organisms. It was established that the introduction of a neutral impurity into the quantum dot, which creates stretching deformation, leads to a decrease in the concentration of interstitial Cdi on the QD surface. [ABSTRACT FROM AUTHOR]

Abstract The nonspecific nature of cancer drug delivery often results in substantial toxic side effects during treatments for breast cancer. To mitigate these negative outcomes, our approach involves loading methotrexate (MTX) within carbon quantum dots (CQDs) synthesized from folic acid, which are then enveloped in exosomal membranes obtained from breast cancer cells (Ex@MTX-CQDs). Analysis utilizing nanoparticle tracking techniques has demonstrated that these Ex@MTX-CQDs maintain the physical and biochemical properties of their exosomal precursors. The release profile of MTX indicated a restricted release percentage (less than 10%) under normal physiological conditions, which is contrasted by a more consistent release rate (approximately 65%) when emulating the conditions found within tumor tissues. The toxicological assessments have confirmed that the presence of exosomes combined with leftover folic acid significantly improves the delivery efficacy of MTX directly to the cancerous cells through the binding to folate and heparan sulfate proteoglycan receptors. This process results in increased disruption of the mitochondrial membrane potential and subsequently triggers apoptosis, ultimately leading to the destruction of cancerous cells. Our research could potentially contribute to the further innovation and application of nanocarriers derived from biological sources for the targeted treatment of breast cancer.

Free space optical communication with infrared light is a promising secure wireless optical communication technology, where infrared photodetectors are the core component. To date, such applications are based on epitaxial growth narrow‐band semiconductors facing the challenge of large‐area fabrication. Infrared colloidal quantum dots (CQDs) are of interest because of the high‐throughput solution processing. Here, large‐area CQD photodetectors with adjustable wavelengths covering 1.3–2.0 µm. For 1 × 1 mm2 CQD photodetector, the response time achieved within 1 µs at room temperature, responded sharply to the 25 kbps PRBS‐7 communication code is demonstrated. For 1.5 × 1.5 cm2 large‐area CQD photodetectors, a communication rate of 2 kbps is achieved. This work is a step toward the CQD application in the field of optical communications. [ABSTRACT FROM AUTHOR]

The nonspecific nature of cancer drug delivery often results in substantial toxic side effects during treatments for breast cancer. To mitigate these negative outcomes, our approach involves loading methotrexate (MTX) within carbon quantum dots (CQDs) synthesized from folic acid, which are then enveloped in exosomal membranes obtained from breast cancer cells (Ex@MTX-CQDs). Analysis utilizing nanoparticle tracking techniques has demonstrated that these Ex@MTX-CQDs maintain the physical and biochemical properties of their exosomal precursors. The release profile of MTX indicated a restricted release percentage (less than 10%) under normal physiological conditions, which is contrasted by a more consistent release rate (approximately 65%) when emulating the conditions found within tumor tissues. The toxicological assessments have confirmed that the presence of exosomes combined with leftover folic acid significantly improves the delivery efficacy of MTX directly to the cancerous cells through the binding to folate and heparan sulfate proteoglycan receptors. This process results in increased disruption of the mitochondrial membrane potential and subsequently triggers apoptosis, ultimately leading to the destruction of cancerous cells. Our research could potentially contribute to the further innovation and application of nanocarriers derived from biological sources for the targeted treatment of breast cancer. [ABSTRACT FROM AUTHOR]

The effective conversion of carbon dioxide (CO2) into valuable chemical fuels relies significantly on the donation of multiple electrons. Its efficiency is closely linked to both the density and lifetime of excited charge carriers. In this study, a hybrid catalyst system comprising covalently bonded InP/ZnS quantum dots (QDs) and Re‐complexes is showcased. The electronic band alignment between the QDs and the Re‐complexes is revealed to dominate the multi‐electron transfer process for photocatalytic conversion to methane (CH4). Notably, the size of the QDs is found to be a determining parameter. Among the three QD sizes investigated, transient absorption spectroscopy studies unveil that rapid multi‐electron transfer from the QDs to the Re‐catalyst occurs in smaller QDs (2.3 nm) due to the substantial driving force. Consequently, the photocatalytic conversion of CO2 to CH4 is significantly enhanced with a turnover number of 6, corresponding to the overall apparent quantum yield of ≈1%. This research underscores the possibilities of engineering multi‐electron transfer by manipulating the electronic band alignment within a catalytic system. This can serve as a guide for optimizing photocatalytic CO2 reduction. [ABSTRACT FROM AUTHOR]

We study the electron tunneling (ET) and local Andreev reflection (AR) processes in a quantum dot (QD) coupled to the left and right ferromagnetic leads with noncollinear ferromagnetisms. In particular, we consider that the QD is also side-coupled to a nanowire hosting Majorana bound states (MBSs) at its ends. Our results show that when one mode of the MBSs is coupled simultaneously to both spin-up and spin-down electrons on the QD, the height of the central peak is different from that if the MBS is coupled to only one spin component electrons. The ET and AR conductances, which are mediated by the dot–MBS hybridization, strongly depend on the angle between the left and right magnetic moments in the leads. Interaction between the QD and the MBSs will result in sign change of the angle-dependent tunnel magnetoresistance. This is very different from the case when the QD is coupled to regular fermonic mode, and can be used for detecting the existence of MBSs, a current challenge in condensed matter physics under extensive investigations. [ABSTRACT FROM AUTHOR]

Strain-free GaAs cone-shell quantum dots have a unique shape, which allows a wide tunability of the charge-carrier probability densities by external electric and magnetic fields. Here, the influence of a lateral electric field on the optical emission is studied experimentally using simulations. The simulations predict that the electron and hole form a lateral dipole when subjected to a lateral electric field. To evaluate this prediction experimentally, we integrate the dots in a lateral gate geometry and measure the Stark-shift of the exciton energy, the exciton intensity, the radiative lifetime, and the fine-structure splitting (FSS) using single-dot photoluminescence spectroscopy. The respective gate voltage dependencies show nontrivial trends with three pronounced regimes. We assume that the respective dominant processes are charge-carrier deformation at a low gate voltage U, a vertical charge-carrier shift at medium U, and a lateral charge-carrier polarization at high U. The lateral polarization forms a dipole, which can either enhance or compensate the intrinsic FSS induced by the QD shape anisotropy, dependent on the in-plane orientation of the electric field. Furthermore, the data show that the biexciton peak can be suppressed by a lateral gate voltage, and we assume the presence of an additional vertical electric field induced by surface charges. [ABSTRACT FROM AUTHOR]

For the first time, a novel mercaptosuccinic acid‐capped tungsten telluride quantum dot (MSA‐WTe3‐QD)‐based electrochemical aptasensor was designed for the determination of SARS‐CoV‐2 N‐protein in synthetic human serum, plasma and urine. The MSA‐WTe3‐QD which exhibited spherical morphology and an average diameter of 3.56 nm were synthesized through a bottom‐up approach. The aptasensor was prepared by firstly immobilizing MSA‐WTe3‐QD on a screen‐printed carbon electrode (SPCE) by using the 1‐ethyl‐3‐(3‐dimethylaminopropyl)carbodiimide/N‐hydroxysuccinimide (EDC/NHS) coupling chemistry. Thereafter, amine‐terminated 90‐mer ssDNA aptamer was deposited on the modified SPCE and left to cure to form the aptasensor. Using the chronocoulometry signal transduction technique, the aptasensor's calibration with N‐protein gave a linear range value of 1–9 pg.mL−1 and a limit of detection (LOD) value of 0.08 pg.mL−1. The LOD value of the aptasensor was 8 times lower than the LOD value of 0.71 pg.mL−1 obtained with a commercial N‐protein ELISA kit. When tested in simulated real samples the aptasensor recovery rates of 95–103.33 % were obtained. In the presence of various interferents, the aptasensor displayed good selectivity to N‐protein. [ABSTRACT FROM AUTHOR]

This study presents a novel photodiode technology with augmented optoelectronic capabilities through the incorporation of quantum dots (QDs). The photodiode, composed of Indium Gallium Zinc Oxide‐Tellurium (IGZO‐Te), is engineered for enhanced light sensitivity and tailored optoelectronic interactions. The primary application of this advanced photodiode lies in the domain of artificial intelligence and machine learning, where it plays a pivotal role in simulating synaptic connections for image processing tasks. Due to the exceptional optical and electrical properties of the IGZO‐Te‐QDs active material combination, the photodiode demonstrates consistent and dependable optical synaptic functions linked to learning. This is achieved through conduction modulation and time duration modulation of light stimulus. In addition, the opto‐synaptic functionalities such as short‐term and long‐term memory has also been successfully demonstrated not only on single device but also on 6 × 6 photodiodes array device. These findings underscore the significant potential of the hybrid structure of IGZO‐Te with QDs in optical artificial neuromorphic chips. [ABSTRACT FROM AUTHOR]

CdS quantum dots (QDs) are widely employed as photocatalysts for reactions such as hydrogen evolution, and their degradation under aerobic aqueous conditions is well understood. However, despite evidence of aggregation and precipitation of CdS QD photocatalysts under anaerobic conditions, catalyst speciation and degradation under such conditions are underexplored. In this work, we demonstrate that during a reductive dehalogenation reaction, CdS QDs undergo surface ligand etching, which leads to a loss of colloidal stability and the formation of microcrystalline cadmium metal deposits. We hypothesize that this results from the accumulation of electrons on the QD surface. In addition, we demonstrate mild surface sulfur oxidation and the formation of an ammonium salt byproduct of a commonly used hole quencher. This work adds to our atomic-level understanding of the reactions occurring at the QD surface during photocatalysis, so that we can design more stable and efficient photocatalysts for organic synthesis. [ABSTRACT FROM AUTHOR]

We study the confinement of a quantum particle to the squared cotangent potential in the background of global monopole spacetime. By dealing with s-states, we obtain the energy levels from the exact solutions to the Schrödinger equation. Then, we show that the topology of the global monopole spacetime influences the energy levels. Further, we show that there is a non-null revival time with regard to the squared cotangent potential and how it is influenced by the global monopole topology. [ABSTRACT FROM AUTHOR]

Quantum dots currently possess significant importance in the field of biomedical science. Upon introduction into the body, quantum dots exhibit a tendency to accumulate in diverse tissues including the central nervous system (CNS). Consequently, it becomes imperative to devote specific attention to their potential toxic effects. Moreover, the preservation of optimal CNS function relies heavily on blood–brain barrier (BBB) integrity, thereby necessitating its prioritization in neurotoxicological investigations. A more comprehensive understanding of the BBB and CNS characteristics, along with the underlying mechanisms that may contribute to neurotoxicity, will greatly aid researchers in the development of effective design strategies. This article offers an in‐depth look at the methods used to reduce the harmful effects of quantum dots on the nervous system, alongside the progression of effective treatments for brain‐related conditions. The focal point of this discussion is the BBB and its intricate association with the CNS and neurotoxicology. The discourse commences by recent advancements in the medical application of quantum dots are examined. Subsequently, elucidating the mechanisms through which quantum dots infiltrate the human body and traverse into the brain. Additionally, the discourse delves into the factors that facilitate the passage of quantum dots across the BBB, primarily encompassing the physicochemical properties of quantum dots and the BBB's inherent capacity for self‐permeability alteration. Furthermore, a concluding summary is presented, emphasizing existing research deficiencies and identifying promising avenues for further investigation within this field. This article explores quantum dots' biomedical applications, emphasizing their potential neurotoxicity and impact on the blood‐brain barrier (BBB). It discusses methods to mitigate quantum dots' harmful effects on the nervous system and highlights advancements in brain‐related treatments. The focus is on understanding BBB integrity, quantum dots' mechanisms of entry into the CNS, and factors influencing their passage across the barrier. The conclusion underscores research gaps and suggests future avenues for investigation in this field. [ABSTRACT FROM AUTHOR]

Carbon quantum dots (CQDs) were prepared by electro-chemical reaction method under reaction conditions such as time and current. The current is 30 mA and time is 3 h. The samples were analyzed using X-ray diffraction, transmission electron microspectroscopy, Fourier transform infrared spectroscopy, photoluminescence spectroscopy, UV–visible spectroscopy, and Hall effect. The results showed that the crystal size calculated by Debye–Scherrer's formula was 70 nm and a greater peak of 1577 cm−1 obtained from FTIR corresponded to C꞊C, which refers to CQDs. The generated energy surface state was measured, which is 3.17, 2.54, 2.33, and 2.01 eV, and the change in the size of surface state was measured, which is 3.372, 3.089, 2.891, and 2.685 nm, respectively, and the free carrier concentration was 5.008 × 108 cm−2, where it was the nanostructure. It was found by measuring the Hall effect that the CQDs were p-type. [ABSTRACT FROM AUTHOR]

In the filtered optical feedback system, a part of the emission of the laser is spectrally filtered, here by a Fabry–Perot (FP) filter, and then fed back into the quantum-dot (QD) laser cavity. This technique has been used in various applications such as inducing frequency dynamics in QD semiconductor lasers and studying the dynamical behavior of a QD semiconductor laser subject to delayed filtered optical feedback. We report on the systematical investigation of the steady-state regime and the dynamical behavior of a QD semiconductor laser subject to delayed FOF. The effects of the filter on the locking of the QD laser frequency to the external cavity modes are described. We report and observe hysteresis, bistability, and multistability and show that all these are well described by a set of rate equations for the coupled QD laser and FP cavity system. We also present a stability diagram that summarizes the dynamical behavior of the system. [ABSTRACT FROM AUTHOR]

The growing demand for wearable and attachable displays has sparked significant interest in flexible quantum-dot light-emitting diodes (QLEDs). However, the challenges of fabricating and operating QLEDs on flexible substrates persist due to the lack of stable and low-temperature processable charge-injection/-transporting layers with aligned energy levels. In this study, we utilized NiOx nanoparticles that are compatible with flexible substrates as a hole-injection layer (HIL). To enhance the work function of the NiOx HIL, we introduced a self-assembled dipole modifier called 4-(trifluoromethyl)benzoic acid (4–CF3–BA) onto the surface of the NiOx nanoparticles. The incorporation of the dipole molecules through adsorption treatment has significantly changed the wettability and electronic characteristics of NiOx nanoparticles, resulting in the formation of NiO(OH) at the interface and a shift in vacuum level. The alteration of surface electronic states of the NiOx nanoparticles not only improves the carrier balance by reducing the hole injection barrier but also prevents exciton quenching by passivating defects in the film. Consequently, the NiOx-based red QLEDs with interfacial modification demonstrate a maximum current efficiency of 16.1 cd/A and a peak external quantum efficiency of 10.3%. This represents a nearly twofold efficiency enhancement compared to control devices. The mild fabrication requirements and low annealing temperatures suggest potential applications of dipole molecule-modified NiOx nanoparticles in flexible optoelectronic devices. [ABSTRACT FROM AUTHOR]

The study aims to create a highly responsive gas sensor for TEA. In order to achieve this goal, spherical ZnO with layered structure was synthesized by a simple hydrothermal method. Subsequently, Ag quantum dots (QDs) are precipitated onto the surface of the ZnO microspheres. The ZnO microspheres were analyzed to demonstrate that they are comprised of porous nanosheets measuring roughly 10 μm in diameter. The composite with the optimal mass percentage displayed outstanding sensitivity to triethylamine (TEA), yielding a response of 1223, approximately 90 times higher than that of the pure ZnO sensor. Furthermore, this composite also demonstrated remarkable selectivity towards TEA. The exceptional detection results were achieved due to the catalytic influence of Ag as a precious metal, coupled with the distinctive structure of quantum dots and ZnO materials. [ABSTRACT FROM AUTHOR]

The 2023 Nobel Prize in Chemistry was awarded to Aleksey I. Ekimov (prize share 1/3), Louis E. Brus (prize share 1/3), and Moungi G. Bawendi (prize share 1/3) for groundbreaking inventions in the field of nanotechnology, i.e., for the discovery and synthesis of semiconductor nanocrystals, also termed quantum dots, that exhibit size-dependent physicochemical properties enabled by quantum size effects. This feature article summarizes the main milestones of the discoveries and developments of quantum dots that paved the road to their versatile applications in solid-state lighting, display technology, energy conversion, medical diagnostics, bioimaging, and image-guided surgery. [ABSTRACT FROM AUTHOR]

Accurate and sensitive analysis of cancer‐associated microRNAs in living tissue is of great significance for the early diagnosis and treatment of cancer. Herein, a hierarchical nanoprobe denoted as UCNP‐QDs‐GNPs is delicately designed, where a near‐infrared (NIR) absorptive upconversion nanoparticle (UCNP) serves as the core, broad‐absorptive and bright emissive quantum dots (QDs) and emission‐quencher gold nanoparticles (GNPs) surround as satellites for microRNA imaging and image‐guided cancer therapy. Through the programmed assembly of heterobivalent DNA‐conjugated QDs with DNA‐modified GNPs and UCNPs, the well‐defined nanostructured UCNP‐QDs‐GNPs are generated with quenched fluorescence. Upon encountering the microRNA‐21 target, GNPs underwent catalytic disassembly, resulting in the concurrent recovery and amplification of fluorescence from QDs and UCNPs, which enabled sensitive imaging and quantification of microRNA‐21 within living cells. Furthermore, dithiol‐constituted aggregation‐induced emission (AIE) photosensitizers bonded on the surface of QDs, are effectively photosensitized by the QDs. The NIR excitation harvested by UCNPs is therefore efficiently transferred to QDs and subsequently converged on the AIE photosensitizers, boosting photodynamic activity for image‐guided therapy in deep‐seated tumors. The DNA‐programmed (de)hybridization strategy, facilitating the conversion of NIR excitation into imaging signals and photodynamic activity, offers a promising avenue for the early theranostics of malignancies. [ABSTRACT FROM AUTHOR]