Green Quantum Dots Research Articles

Toxicity optimization of green zinc oxide quantum dots in zebrafish using Box-Behnken design: a novel approach for safer nanoparticle synthesis

Zinc oxide quantum dots, also known as ZnO QDs, are highly desirable due to their numerous favorable characteristics, such as their beneficial photoluminescence, solubility in water, along with sunlight absorption. They are well-suited for use in biomedical applications, drugs, and bioimaging. However, study on the in-vivo toxicology of these QDs is needed before they can be used in humans. Zebrafish (Danio rerio) are cheap, fast-growing, and similar to humans, which makes them ideal as in vivo model for studying the toxicity of nanomaterials. The toxicity investigations involving zinc oxide QDs (ZnO QDs) and zinc oxide bionanocomposite (ZnO BC) in zebrafish that were concentration-dependent are evaluated, and the Box-Behnken design (BBD) was utilized to optimize the results. To determine the proper dosage, a study on cell line as well as hemocompatibility was carried out prior to testing the toxic effects of ZnO QDs along with ZnO BC upon zebrafish. When administered at 2.5 μg/l of ZnO BC and 2 μg/l of ZnO QDs, neither ZnO BC nor ZnO QDs appeared to be toxic to embryos during hatching and development. The testing of larval behavior in visible light revealed a dose-dependent decrease in both the total diving distance as well as speed. Nevertheless, at ZnO BC and ZnO QDs levels >250 μg/l and >200 μg/l, respectively, notable effects were seen in zebrafish embryos. Hence, ZnO QDs and BC at low concentrations were notably nontoxic. In order to guarantee the safety of nanomaterials in bio applications, this research supports upcoming in-vivo imaging investigations on their harmful effects.

Enhanced Fluorescence in Green ZnSeTe Quantum Dots Using Gradient Layer Technique

AbstractA novel method is presented for synthesizing green ZnSeTe quantum dots (QDs) that demonstrate high photoluminescence quantum yield (PLQY) and a narrow full width at half maximum (FWHM). In this synthesis, a gradient layer is created between the ZnSeTe core and the ZnSe inner shell by utilizing the different reactivities of precursors. This innovative approach aims to reduce lattice mismatch and minimize interfacial defects, thereby enhancing the fluorescence properties of ZnSeTe QDs. Using the gradient layer, green QDs are achieved with a FWHM of 36 nm and a PLQY of 90%, surpassing previous results. Detailed structural analyses confirmed a reduction in stacking faults and strain in the QDs with a gradient layer, leading to enhanced fluorescence properties. The QDs with a gradient layer are successfully integrated into the emissive layer of a quantum dot light–emitting diode device, demonstrating superior performance compared to QDs without the gradient layer.

Biophysical translational posterity of green carbon quantum dots: the unparalleled versatility

Biophysical translational posterity of green carbon quantum dots: the unparalleled versatility

Synthesis and luminescence properties of carbon quantum dots with core@shell structures

The luminescence stability of carbon quantum dots (CQDs) in air impedes their extensive applications. Ample –NH2 groups on the surface of a green carbon quantum dots (GCQDs) had high organic reactivity, the surface of GCQDs was modified with allyl functional groups through a simple surface substitution reaction (named as GCQD-A). The surface of the GCQD-A was continuously formed a thin organic shell by free radical copolymerization reaction with methyl methacrylate and styrene respectively, and they were named as GCQD@PMMA and GCQD@PS respectively. The allyl functional groups on the surface of GCQD-A, the shell composition of GCQD@PMMA and GCQD@PS were characterized by their 1H nuclear magnetic resonance (1H NMR) data and infrared adsorption spectra. The luminescence stabilities for GCQD@PMMA and GCQD@PS in air were greatly improved compared with that for the GCQDs. The work can provide a novel method to get stable luminescence of CQDs in air, and it will extend their application areas in solid state.

Dynamic fluorescent patterns inspired by cuttlefish for anti-counterfeiting applications

Dynamic fluorescent patterns that convert external stimulation into intuitive color changes have drawn significant interest in various fields. However, the complex synthesis of materials with multiple emissions and technical barriers in the flexible fabrication of full-color fluorescent patterns hinder their applicability in diverse scenarios. Here, we present a bioinspired dynamic fluorescent pattern fabricated by femtosecond laser-induced forward transfer (FsLIFT), inspired by cuttlefish. The elastomeric substrate can contract and expand as muscle fibers of cuttlefish, and the patterned red, green, and blue quantum dot (QD) films can be regarded as pigment cells, achieving bionic preparation of function and morphology similar to cuttlefish. Notably, the fluorescent patterns can be modulated by manipulating strains and excitations. Using this bioinspired strategy, we successfully produced an advanced fluorescent anti-counterfeiting label via FsLIFT, which can only be recognized under specific strain and excitation light conditions. These dynamic fluorescent patterns show broad application potential in anti-counterfeiting, wearable devices, and information encryption.

Fluorescent Polylactic acid composite incorporating lignin-based carbon quantum dots for sustainable 4D printing applications

Fluorescent 4D printing materials, as innovative materials that combine fluorescent characteristics with 4D printing technology, have attracted widespread interest and research. In this study, green lignin-derived carbon quantum dots (CQDs) were used as the fluorescent module, and renewable poly(propylene carbonate) polyurethane (PPCU) was used for toughening. A new low-cost fluorescent polylactic acid (PLA) composite filament for 4D printing was developed using a simple melt extrusion method. The strength of the prepared composite was maintained at 32 MPa, while the elongation at break increased 8-fold (34 % increase), demonstrating excellent shape fixed ratio (∼99 %), recovery ratio (∼92 %), and rapid shape memory recovery speed. The presence of PPCU prevented fluorescence quenching of the CQDs in the PLA matrix, allowing the composite to emit bright green fluorescence under 365 nm ultraviolet light. The composite exhibited shear thinning behavior and had an ideal melt viscosity for 3D printing. The results obtained demonstrated the versatility of these easy-to-manufacture and low-cost filaments, opening up a novel and convenient method for the preparation of strong, tough, and multifunctional PLA materials, increasing their potential application value.

Design, Characterization and Biopharmaceutical Applications of Novel Green Boron-Carbon Quantum Dots for Quantification of Apalutamide; Greenness Evaluations.

The diagnosis of prostate cancer has been evolving in the current decade, with expected mortality rates of 499,000 death by the year 2030. Apalutamide (APL) has been approved in 2018 as the first drug for the controlling of prostate cancer. APL significant success warrantied its high global sales, which are expected to surpass 58% of segment market sales (together with another drug; enzalutamide). Therefore, new, fast and environmentally friendly analytical methods are required for its determination for the quality control and biological monitoring purposes. The proposed research designs and evaluates the first fluorimetric approach based on novel porous green boron-doped carbon quantum dots (B@CDs) for the determination of APL in biopharmaceutical matrices. The synthetic approach has high quantum yield (31.15%). B@CDs were characterized using several tools, including transmission electron microscopy (TEM), dynamic light scattering (DLS), FTIR and Energy dispersive X-ray spectroscopy (EDX) which proved their improved surface properties with an average nano-diameter of 3.0nm. The interaction between B@CDs and APL led to enhancement their fluorescence at 441nm (excitation at 372nm). The approach was validated for the determination of APL within concentration range of 15.0-700.0 ng mL- 1 with quantification limit LOQ 4.37 ng mL- 1 and detection limit LOD 1.44 ng mL- 1. The approach was successfully applied for the determination of APL in human plasma and pharmaceutical monitoring of its marketed tablet form. Then, the approach was assessed for its environmental impact using different metrics and proved its ecological greenness.

Fluorometric detection of β-carotene with novel green synthesis carbon quantum dot from Asphodelus

Asphodelus-based CQDs were successfully synthesized in a single step by the hydrothermal synthesis method for detection of β-carotene. TEM, XRD, FTIR, XPS, Zeta potential, UV–Vis absorption and fluorescence measurements were taken to structurally and optically characterize the newly synthesized CQDs. It was determined that the characterized CQDs show high selectivity and sensitivity only to β-carotene among 11 different biomolecules. The detection limit of CQDs for β-carotene was calculated as 8.28 µM. It was determined that the new CQDs respond very quickly and stably without interfering with any other biomolecules. The studies in different pH environments exhibited that CQDs can detect β-carotene at all pH studied. Real sample experiments show that β-carotene can be determined accurately and reliably in practical applications with the novel CQDs. It was thought that the results obtained from this study will make significant contributions to the studies on β-carotene detection, which are limited in the literature.

Synthesis of Red, Green, and Blue Carbon Quantum Dots and Construction of Multicolor Cellulose‐Based Light‐Emitting Diodes

Synthesis of Red, Green, and Blue Carbon Quantum Dots and Construction of Multicolor Cellulose‐Based Light‐Emitting Diodes

Shelf-Stable Green and Blue Quantum Dot Light-Emitting Diodes with High Efficiencies.

Quantum dot light-emitting diodes (QLEDs) are promising electroluminescent devices for next-generation display and solid-state lighting technologies. Achieving shelf-stable and high-performance QLEDs is crucial for their practical applications. However, the successful demonstration of shelf-stable QLEDs with high efficiencies is limited to red devices. Here, we developed a solution-based amine ligand exchange strategy to passivate the surfaces of optical ZnO (O-ZnO) nanocrystals, leading to suppressed exciton quenching at the green and blue QD/oxide interface. Furthermore, we designed new bilayered oxide electron-transporting layers consisting of amine-modified O-ZnO/conductive ZnO. This design simultaneously offers suppressed interfacial exciton quenching and sufficient electron transport in the green and blue QLEDs, resulting in shelf-stable green and blue devices with high efficiencies. Our devices exhibit neglectable changes in external quantum efficiencies (maximum external quantum efficiencies of 22.4% for green and 14.3% for blue) after storage for 270 days. Our work represents a step forward in the practical applications of QLED technology.

High-brightness green CdSe/ZnS quantum dots stimulated by solar-blind deep-ultraviolet light in optical wireless communications.

Ultraviolet-based optical wireless communication (OWC) is emerging as a significant technology for the next-generation secure communication, particularly within the solar-blind spectra. In this study, we have synthesized two types of green-emitting II-VI family colloidal quantum dots (QDs), specifically ZnCdSe/ZnS and CdSe/CdZnS/ZnS QDs, which are stimulated by ultraviolet (UV) and solar-blind deep-ultraviolet (DUV) light, respectively. With a transmission distance of 1.5 m, the maximum data rate of ZnCdSe/ZnS QDs reaches 40 Mb/s, which is below the forward-error-correction (FEC) limit (3.8 × 10-3) when excited by 385-nm UV light. However, both brightness and bit error rate are significantly deteriorated when excited by 280-nm DUV light. Conversely, 28 and 24 Mb/s were attained using CdSe/CdZnS/ZnS QDs under UV and DUV excitation, respectively. Our studies on light-conversion and communication capabilities of green QDs within the DUV OWC system may provide valuable insights for subsequent research in the field.

When quantum dots meet blue phase liquid crystal elastomers: visualized full-color and mechanically-switchable circularly polarized luminescence

Polymer-based circularly polarized luminescence (CPL) materials with the advantage of diversified structure, easy fabrication, high thermal stability, and tunable properties have garnered considerable attention. However, adequate and precise tuning over CPL in polymer-based materials remains challenging due to the difficulty in regulating chiral structures. Herein, visualized full-color CPL is achieved by doping red, green, and blue quantum dots (QDs) into reconfigurable blue phase liquid crystal elastomers (BPLCEs). In contrast to the CPL signal observed in cholesteric liquid crystal elastomers (CLCEs), the chiral 3D cubic superstructure of BPLCEs induces an opposite CPL signal. Notably, this effect is entirely independent of photonic bandgaps (PBGs) and results in a high glum value, even without matching between PBGs and the emission bands of QDs. Meanwhile, the lattice structure of the BPLCEs can be reversibly switched via mechanical stretching force, inducing on-off switching of the CPL signals, and these variations can be further fixed using dynamic disulfide bonds in the BPLCEs. Moreover, the smart polymer-based CPL systems using the BPLCEs for anti-counterfeiting and information encryption have been demonstrated, suggesting the great potential of the BPLCEs-based CPL active materials.

Mango Leaves (Mangifera indica)-Derived Highly Florescent Green Graphene Quantum Dot Nanoprobes for Enhanced On-Off Dual Detection of Cholesterol and Fe2+ Ions Based on Molecular Logic Operation.

In the present study, we have engineered a molecular logic gate system employing both Fe2+ ions and cholesterol as bioanalytes for innovative detection strategies. We utilized a green-synthesis method employing the mango leaves extract to create fluorescent graphene quantum dots termed "mGQDs". Through techniques like HR-TEM, i.e., high-resolution transmission electron microscopy, Raman spectroscopy, and XPS, i.e., X-ray photoelectron spectroscopy, the successful formation of mGQDs was confirmed. The photoluminescence (PL) characteristics of mGQDs were investigated for potential applications in metal ion detection, specifically Fe2+ traces in water, by using fluorescence techniques. Under 425 nm excitation, mGQDs exhibited emission bands at 495 and 677 nm in their PL spectrum. Fe2+-induced notable quenching of mGQDs' PL intensity decreased by 97% with 2.5 μM Fe2+ ions; however, adding 20 mM cholesterol resulted in a 92% recovery. Detection limits were established through a linear Stern-Volmer (S-V) plot at room temperature, yielding values of 4.07 μM for Fe2+ ions and 1.8 mM for cholesterol. Moreover, mGQDs demonstrated biocompatibility, aqueous solubility, and nontoxicity, facilitating the creation of a rapid nonenzymatic cholesterol detection method. Selectivity and detection studies underscored mGQDs' reliability in cholesterol level monitoring. Additionally, a molecular logic gate system employing Fe2+ metal ions and cholesterol as a bioanalyte was established for detection purposes. Overall, this research introduces an ecofriendly approach to craft mGQDs and highlights their effectiveness in detecting metal ions and cholesterol, suggesting their potential as versatile nanomaterials for diverse analytical and biomedical applications.

Green emissive nitrogen-doped graphene quantum dots for fluorescence off–on probing methimazole via palladium (II) mediated assay

A palladium ion ([Formula: see text])-mediated nitrogen-doped graphene quantum dots (N-GQDs/Pd[Formula: see text]) was developed as a fluorescent “off–on” probe for methimazole (MZ). Fluorescent N-GQDs interact with Pd[Formula: see text] through coordination interactions, leading to weak photoluminescence (PL) owing to the quenching ability of Pd[Formula: see text]. Upon introducing MZ, the stronger binding between N-GQDs and Pd[Formula: see text] destroys the N-GQDs/Pd[Formula: see text] complex and restores the PL of N-GQDs. The probe exhibits a linear PL response to MZ concentrations from 3.0 to 50.0 [Formula: see text]M with a detection limit down to 4.5 nM. In addition, the probe has been used to detect MZ in real samples including natural water sources and human urine.

Red and green inverted top-emitting quantum dot light-emitting diodes using CMOS-based electrodes for microdisplay applications

Silicon (Si) substrates and complementary metal-oxide-semiconductor (CMOS) technology are being used in microdisplays in augmented reality/virtual reality devices owing to higher pixel resolution. Quantum-dot light-emitting diodes (QLEDs) incorporating colloidal quantum dots have emerged as promising devices for display applications owing to their exceptional color, high luminance, and solution processibility. However, studies on QLEDs on Si, particularly for microdisplay applications, remain limited. This study investigated the device characteristics of inverted top-emitting QLEDs using Si substrates and various CMOS process-based electrode materials (aluminum (Al), Al/titanium nitride (TiN), titanium, cobalt, and tungsten) for microdisplay applications. Devices incorporating a thin TiN layer on an Al electrode exhibited the highest efficiency and luminance compared to those with other electrodes. We successfully fabricated red and green inverted top-emitting QLEDs using microdisplay pixel-structured Al/TiN electrodes, with pixel pitch and fill factor of 10.8 μm × 3.6 μm and 72.5 %, respectively. Further, the device efficiency was optimized by changing hole and electron transport layer thicknesses, resulting in different efficiencies and electroluminescence spectra owing to the microcavity effect. Optical simulations demonstrated consistency with the measured values. Thus, the selection of the bottom electrode and a suitable design that considers the microcavity effect are crucial for high-performance QLED-based microdisplays.

44‐3: High Efficiency and Brightness Quantum Rods Light Emitting Diode

Despite substantial efforts, the maximum external quantum efficiency (EQE) of red, green, and blue quantum dots remains close to 25%, limited by the outcoupling efficiency of specific device optical structures. Further improvements have primarily focused on optimizing light management. In this study, we employed rod‐shaped nanocrystals instead of sphere‐like quantum dots as the light‐emitting layer. The theoretical device outcoupling efficiency significantly increased to nearly 41% due to the intrinsic horizontal dipole alignment within the quantum rod film, nearly doubling the efficiency compared to quantum dot light‐emitting diodes (QDLEDs). As a result, we achieved record‐high EQEs of 14.1% for green quantum rod light‐emitting diodes, with maximum brightness exceeding 150,000 cd/m 2 , respectively. Our research demonstrates the immense potential of QRLEDs for display and lighting applications, paving a new way for the commercialization of nanocrystal particles.

Synthesis of organic solvent‐free nitrogen‐doped carbon quantum dots as unique green fluorimetric probes for analysis of abrocitinib in human plasma

AbstractAtopic dermatitis (AD) is a persistent, inflammatory skin condition that impacts approximately 15 to 20% of children and 1 to 3% of adults globally. Common skin manifestations include papules, papulovesicular, and brown or red patches with swelling, crusting, and flaking. Therefore, the drug abrocitinib (ABR) was approved by the US FDA as an oral treatment for atopic dermatitis. The present study outlines the development of innovative, thermostable, and pH‐stable organic solvent‐free nitrogen‐doped carbon dots (N@CQDs) synthesized through a one‐step method for evaluating ABR with a notable quantum yield of 33.84% to minimize the use of organic solvents. Their cost‐effectiveness, eco‐friendly characteristics, and outstanding photocatalytic properties have established them as a promising alternative to conventional luminescent techniques like fluorescent dyes and luminous derivatization technique. The reaction of ABR with N@CQDs led to a significant decrease in the luminescent response of the produced green and stable carbon quantum dots at 513 nm. The detection range was determined to be 1.0–150.0 ng mL−1, with a lower limit of quantitation (LOQ) equal to 0.52 ng mL−1 based on the linear graph. The green method effectively used for analysis of ABR in pharmaceutical tablets and pharmacokinetic study with high sensitivity.

P‐155: A High‐resolution Patterning of Electroluminescent Quantum Dot Pixels via Photo‐crosslinking

The emergence of near‐eye displays for an extended reality (XR) has promoted the development of high‐resolution electroluminescence quantum dot (EL‐QD) devices. Direct photo‐lithography using photosensitive moieties is an effective technique for producing micrometer‐sized patterns of colloidal quantum dots. Here, we fabricated red, green, and blue quantum dot patterns with a resolution of >4,500 pixels per inch using an azide‐based photo‐crosslinking method, which is a simple and applicable to a versatile patterning or integrating process. The effect of QD ligands and solvents on the electroluminescence characteristics and pattern fidelity of QD films during the patterning process was studied.

Epimedium brevicornu maxim. -derived green carbon quantum dots as chemiluminescence probes for highly sensitive detection of Sulfacetamide and Sulfadimethoxine Sodium Salt

This study presented the synthesis of phosphorus (P) and chlorine (Cl) co-doped carbon quantum dots (P/Cl-CQDs) derived from Epimedium brevicornu Maxim. and established a simple and effective chemiluminescence (CL) system for detecting Sulfacetamide (STM) and Sulfadimethoxine Sodium Salt (STX). Employing traditional Chinese medicine Epimedium brevicornu Maxim. as a green precursor material, (NH4)2HPO4 and NH4Cl were utilized as dopants for P and Cl, respectively. The P/Cl-CQDs was synthesized through a one-step hydrothermal method exhibited excellent CL properties, effectively catalyzing the luminol system and markedly amplifying its CL intensity. Both STM and STX were observed to inhibit the CL intensity of the luminol-(P/Cl-CQDs) system. Based on this, a novel CL method combining flow injection technique was established for the detection of STM and STX. Under optimal conditions, the method demonstrated the capability to detect STM in the range of 1–400 × 10−6 mol/L, with a limit of detection (LOD) of 0.34 × 10−6 mol/L and a relative standard deviation (RSD) of 1.29 %, and STX within the range of 5–280 × 10−6 mol/L, with a LOD of 0.16 × 10−6 mol/L and an RSD of 1.23 %. This method successfully determined the content of STM and STX in pork, with spike recoveries ranging from 100.0 % to 103.8 % for STM and from 98.0 % to 102.3 % for STX.

Fluorescent modification and performance study of carbon quantum dots on twisted bamboo fiber bundles

ABSTRACT In recent years, carbon quantum dots (CQDs) have been employed in the functionalization research of fiber-based materials due to their distinctive physicochemical properties. We used citric acid and urea as precursors and combined with hydrothermal method to prepare green and non-toxic carbon quantum dots (NCQDs), which were loaded into four-color twisted bamboo fiber bundles and possessed photoluminescence effect by simple impregnation method. Based on the verification of the structure and fluorescence properties of NCQDs, the fluorescent twisted bamboo fiber tows were comparatively analyzed for their chemical composition, microscopic morphology, mechanical properties, color difference, and thermal stability. The results showed that the four groups of fluorescent twisted bamboo fiber tows emitted uniform and bright blue fluorescent effects under UV light irradiation, and increased the tensile strength by 19.77% ~ 39.27% and the sexual modulus by 66.11% ~ 88.78% compared with the original twisted bamboo fiber tows. The impregnated carbon quantum dot solution enhances the functionality of the fiber bundle while enriching the color expression. It is expected to be a potential application material in the fields of smart marking, fluorescent anti-counterfeiting, interior decoration, and home textile industry.