CdS Quantum Dots Research Articles

Novel Efficient Selenium-Based D-π-A NIR Polymer Dots Anodic Electrochemiluminescence Emitter and Its Application in Simultaneous Detection of Two Pneumonia Pathogens with CdS Quantum Dots.

Community-acquired pneumonia (CAP) is a major cause of death in children under 5 years old globally. With Streptococcus pneumoniae (S. pneumoniae) and Mycoplasma pneumoniae (M. pneumoniae) being the main pathogens linked to CAP that requires hospitalization, there is an urgent need for a straightforward, cost-efficient, and highly accurate diagnostic method for immediate and early detection of CAP. In this work, benzo[1,2-c;4,5-c']bis([1,2,5]thiadiazole) (BBT) as π-bridge spacer with the donor unit of poly(9,9-dioctylfluorene) (PF) and the acceptor unit of dithienylbenzoselenadiazole (DBS) has been successfully copolymerized to unprecedentedly prepare novel D-π-A selenium-based polymer dots with efficient NIR electrochemiluminescence (named as Se-Pdots in this work). Se-Pdots exclusively generated excellent anodic ECL in the two-component coreaction system comprising TPrA and K2S2O8. Moreover, a potential-resolved ECL biosensor to simultaneously detect S. pneumoniae and M. pneumoniae has also been successfully constructed based on this novel Se-based NIR Pdots as an anodic emitter with CdS QDs as a cathodic emitter. Under optimal conditions, the biosensor has a wide linear range for S. pneumoniae (10-15 to 10-9 M) and M. pneumoniae (10-15 to 10-9 M), with low detection limits for S. pneumoniae (0.56 fM) and M. pneumoniae (0.96 fM). The proposed ECL biosensor provides a simple, sensitive, and reliable method for the simultaneous detection of CAP pathogens in clinical applications.

Electrostatic Self-Assembly of CdS Quantum Dots with Co9S8 Hollow Nanotubes for Enhanced Visible Light Photocatalytic H2 Production.

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.

Highly efficient photocatalytic degradation of rhodamine B by immobilizing CdS quantum dots on ZnCr-layered double hydroxide nanosheets

The removal of Rhodamine B (RhB), a commonly encountered cationic dye in heavily contaminated wastewater streams, from wastewater effluents presents a significant challenge. Herein, we focus on developing an innovative ternary nanocomposite of zinc oxide nanoparticles, quantum dots of cadmium sulfide (CdS QDs), and zinc-chromium carbonate layered double hydroxide nanosheets (ZnCr–CO3-LDH NSs) via a sonochemical synthesis route. The synthesized ternary nanocomposite, CdS QDs@ZnO/ZnCr–CO3-LDH referred to as CZC-LDH, exhibits remarkable photodegradation performance of rhodamine B (RhB) dye under UV-A radiation. A comprehensive investigation into the photocatalytic efficiency and characteristics of CZC-LDH was conducted using various analytical techniques, including XRD, FESEM, DRS, XPS, HR-TEM, PL, and BET (surface area analysis). Results indicate that CZC-LDH demonstrates superior photocatalytic efficiency, achieving 98.26 % degradation of RhB within 3-h only. Moreover, the influence of different scavengers on CZC-LDH photocatalytic efficiency was evaluated to elucidate the plausible RhB photocatalytic degradation pathway. The as-prepared CZC-LDH exhibits exceptional photocatalytic performance, stability, and reusability, positioning it as a promising candidate to previously reported photocatalysts in literature.

The effect of Cu(I)-doping on the photoinduced electron transfer from aqueous CdS quantum dots.

The doping of CdS quantum dots (QDs) with Cu(I) disrupts electron-hole correlation due to hole trapping by the dopant ion, post-photoexcitation. The present paper examines the effect of such disruption on the rate of photoinduced electron transfer (PET) from the QDs to methyl viologen (MV2+), with implications in their photocatalytic activity. A significantly greater efficiency of PL quenching by MV2+ is observed for the doped QDs than for the undoped ones. Interestingly, the Stern-Volmer plots constructed using PL intensities exhibit an upward curvature for both the cases, while the PL lifetimes remain unaffected. This observation is rationalized by considering the adsorption of the quencher on the surface of the QDs and ultrafast PET post-photoexcitation. Ultrafast transient absorption experiments confirm a faster electron transfer for the doped QDs. It is also realized that the transient absorption experiment yields a more accurate estimate of the binding constant of the quencher with the QDs, than the PL experiment.

Reduction reactions at the interface between CdS quantum dot and Z-type ligands driven by electron injection in the electroluminescent processes.

The efficient and stable electroluminescence of quantum dots (QDs) is of great importance in their applications in new display technologies. The short service life of blue QDs, however, hinders their development and commercialization. Different mechanisms have been proposed for the destabilization of QDs in electroluminescent processes. Based on real-time time-dependent density functional theory studies on the QD models covered by Z-type ligands (XAc2, X = Cd, Zn, Mg), the structural evolution is simulated to reveal the mechanism of the reduction reactions induced by electron injection. Our simulations reproduce the experimental observations that the reduction reactions occur at the QD-ligand interface, and the reduced Cd atom is almost in a zero valence state. However, different sites are predicted for the reactions in which the surface metal atom of the QD instead of the metal atom in the ligands is reduced. As a result, one of the arms of the chelate ligand leaves the QD, which tends to cause damage to its electroluminescent performance. Our findings contribute to a mechanistic understanding of the reduction reactions that occurred at the QD-ligand interface.

Enhancement of solar cell performance with the Pb incorporation in CdS quantum dots

Enhancement of solar cell performance with the Pb incorporation in CdS quantum dots

Pathways of CdS Quantum Dot Degradation during Photocatalysis: Implications for Enhancing Stability and Efficiency for Organic Synthesis

Pathways of CdS Quantum Dot Degradation during Photocatalysis: Implications for Enhancing Stability and Efficiency for Organic Synthesis

Effect of Crystal Structure on the Aggregation of CdS Quantum Dots: Consequences for Photophysical Properties and Photocatalytic Hydrogen Evolution Activity

Effect of Crystal Structure on the Aggregation of CdS Quantum Dots: Consequences for Photophysical Properties and Photocatalytic Hydrogen Evolution Activity

Enhanced adsorption and visible-light photocatalytic degradation of CIP by CdS QDs‐Decorated Mn-doped NH2-UiO-66

CdS Quantum dots (QDs) interspersed on the surface of Mn-UiO-66-NH2 (hereafter abbreviated as CdS QDs@Mn-UiO-66-NH2) Z-scheme heterojunction composites were synthesized by solvothermal method for the removal of ciprofloxacin (CIP) under visible light irradiation. The influences of the doping content of Mn and the initial concentrations of CIP on the adsorption capacity and photocatalytic performance were investigated in detail. Compared to the pristine CdS and Mn-UiO-66-NH2, the fabricated CdS QDs@Mn-UiO-66-NH2 composites exhibited enhanced adsorption and photocatalytic capabilities, especially for the CMU-5 with 10 % Mn doping showing around 52.5 % adsorption removal efficiency and about 92 % photocatalytic removal efficiency for CIP (30 mg/L). Various technologies such as XPS, TG and UV–vis DRS have confirmed that the superior catalytic performance of CMU-5 is ascribed to the d-d transitions improving the utilization of visible light after the coordination of the transition metal and the presence of a heterojunction with a tight interfacial structure enhancing the charge transfer. The possible intermediates in the photodegradation process of CIP were detected using gas chromatography-mass spectrometry (GC-MS).

Bifunctional iron-porphyrin metal-organic frameworks for organic photoelectrochemical transistor gating and biosensing

Iron-porphyrin metal-organic frameworks (MOFs) have emerged as a remarkable class of semiconductors with adjustable photoelectrical properties and peroxidase-mimicking activities, yet their full potential remains largely unexplored. The organic photoelectrochemical transistor (OPECT) has been proven to be a prominent platform for diverse applications. Herein, iron-porphyrin MOFs, as bifunctional photo-gating module and horseradish peroxidase-mimicking nanozyme, is explored for novel OPECT bioanalysis. Exemplified by alpha-fetoprotein (AFP)-dependent sandwich immunorecognition and therein glucose oxidase (GOx)-generated H2O2 to etch CdS quantum dots on the surface of iron-porphyrin MOFs, this OPECT bioanalysis achieved high-performance AFP detection with a low detection limit of 24 fg/mL. This work featured a bifunctional iron-porphyrin MOFs gated OPECT, which is envisioned to inspire more interest in developing the diverse MOFs-nanozymes toward novel optoelectronics and beyond.

MOF-derived porous In2O3 nanospheres sensitized by CdS quantum dots: A ppb-level NO2 sensor with ultra-high response at room-temperature

NO2 is one of the most important atmosphere pollutants, causing great harm to the human body at very low concentrations (ppb levels). Herein, a novel fabrication idea for gas sensing materials was reported to detect ppb-level NO2 via MOF-derived porous In2O3 nanospheres (NSs) sensitized by CdS quantum dots (QDs). The good distribution of CdS QDs (2.5–4.0 nm) on porous In2O3 NSs was verified by the transmission electron microscopy and element mapping analyses. In comparison to In2O3 NSs, the CdS@In2O3 composite nanospheres (CNSs) exhibited exceptional responses to ppb-level concentrations of NO2 (S=425.1@100 ppb) at room temperature (RT, 25 °C), while also demonstrating good selectivity and response reproducibility. These improvements in sensing performance were attributed to the synergies of the electronic effects of CdS QDs, MOF-derived porous nanostructures, and enhanced adsorption of NO2 and active O2– by well-dispersed CdS QDs. This work emphasizes that the MOF-derived In2O3 porous NSs sensitized by CdS QDs can accurately detect ppb-level concentrations of the NO2 at RT.

Biosynthesis of photostable CdS quantum dots by UV-resistant psychrotolerant bacteria isolated from Union Glacier, Antarctica.

Quantum Dots (QDs) are fluorescent nanoparticles with exceptional optical and optoelectronic properties, finding widespread utility in diverse industrial applications. Presently, chemically synthesized QDs are employed in solar cells, bioimaging, and various technological domains. However, many applications demand QDs with prolonged lifespans under conditions of high-energy radiation. Over the past decade, microbial biosynthesis of nanomaterials has emerged as a sustainable and cost-effective process. In this context, the utilization of extremophile microorganisms for synthesizing QDs with unique properties has recently been reported. In this study, UV-resistant bacteria were isolated from one of the most extreme environments in Antarctica, Union Glacier at the Ellsworth Mountains. Bacterial isolates, identified through 16S sequencing, belong to the genera Rhodococcus, Pseudarthrobacter, and Arthrobacter. Notably, Rhodococcus sp. (EXRC-4A-4), Pseudarthrobacter sp. (RC-2-3), and Arthrobacter sp. (EH-1B-1) tolerate UV-C radiation doses ≥ 120J/m². Isolated UV-resistant bacteria biosynthesized CdS QDs with fluorescence intensities 4 to 8 times higher than those biosynthesized by E. coli, a mesophilic organism tolerating low doses of UV radiation. Transmission electron microscopy (TEM) analysis determined QD sizes ranging from 6 to 23nm, and Fourier-transform infrared (FTIR) analysis demonstrated the presence of biomolecules. QDs produced by UV-resistant Antarctic bacteria exhibit high photostability after exposure to UV-B radiation, particularly in comparison to those biosynthesized by E. coli. Interestingly, red fluorescence-emitting QDs biosynthesized by Rhodococcus sp. (EXRC-4A-4) and Arthrobacter sp. (EH-1B-1) increased their fluorescence emission after irradiation. Analysis of methylene blue degradation after exposure to irradiated QDs biosynthesized by UV-resistant bacteria, indicates that the QDs transfer their electrons to O2 for the formation of reactive oxygen species (ROS) at different levels. UV-resistant Antarctic bacteria represent a novel alternative for the sustainable generation of nanostructures with increased radiation tolerance-two characteristics favoring their potential application in technologies requiring continuous exposure to high-energy radiation.

Photo-Induced Aldol Condensation of Furfurals with Surface-Modified CdS Quantum Dots

Photo-Induced Aldol Condensation of Furfurals with Surface-Modified CdS Quantum Dots

Ligand‐Induced Digital Programmable Photochromic CdS Materials Toward Dual‐Mode Light‐Printing and Information Encryption

AbstractThe explosive growth of information and its widespread availability underscores the need for robust encryption and anticounterfeiting measures. In this study, CdS quantum dots are engineered (QDs) to manifest multiple visual responses to a single trigger through strategic ligand design. The surface engineering method allows QDs to transition from yellow to black upon photoexcitation‐induced electron transfer from Cd(II) to Cd(0). Surface ligands desorption under hole injection, leading to an increase in QDs size and resulting in a redshift in photoluminescence. This photoexcitation‐induced redox reaction reveals unprecedented photochromism and photoluminescence phenomena, establishing a foundation for advanced information protection measures. Utilizing these QDs, excellent writing performance under UV irradiation is achieved in solid‐state substrates, while a dual‐mode encryption system is realized in gel matrices, opening up new avenues for information encryption as well as cumulative and interactive information protection. Furthermore, the redox reaction of CdS QDs is employed as ink for 3D printing, enabling for the creation of digitally programmable materials with distinct temporally evolving appearances by controlling the oxygen content in the ink to regulate the rate of photochromism. This advancement also sheds light on the progress in 3D printing technology.

Metal Fluorides Passivate II-VI and III-V Quantum Dots.

Quantum dots (QDs) with metal fluoride surface ligands were prepared via reaction with anhydrous oleylammonium fluoride. Carboxylate terminated II-VI QDs underwent carboxylate for fluoride exchange, while InP QDs underwent photochemical acidolysis yielding oleylamine, PH3, and InF3. The final photoluminescence quantum yield (PLQY) reached 83% for InP and near unity for core-shell QDs. Core-only CdS QDs showed dramatic improvements in PLQY, but only after exposure to air. Following etching, the InP QDs were bound by oleylamine ligands that were characterized by the frequency and breadth of the corresponding ν(N-H) bands in the infrared absorption spectrum. The fluoride content (1.6-9.2 nm-2) was measured by titration with chlorotrimethylsilane and compared with the oleylamine content (2.3-5.1 nm-2) supporting the formation of densely covered surfaces. The influence of metal fluoride adsorption on the air stability of QDs is discussed.

Rapid detection of chlortetracycline and metacycline in food based on the fluorescence quenching effect of ZnS@CdS quantum dots

Excessive accumulation of tetracycline can not only cause harm to the environment, but also threaten human health through the food chain. In order to reduce the likelihood of people being harmed by these drugs, new methods for the detection of chlortetracycline (CTC) and metacycline (MTC) based on the ZnS@CdS quantum dot (QDs) fluorescence quenching reaction were established. High quality CdS QDs capped by mercaptopropionic acid and ZnS were prepared, which were characterized by transmission electron microscopy, fluorescence, ultraviolet visible spectra, fourier transform infrared, X-ray diffraction and thermogravimetric analysis. The study showed that there was an interaction between CTC/MTC and ZnS@CdS QDs, and the electrostatic force was the main force. The Stern-Volmer analysis showed that the quenching was static, which was further proved by fluorescence lifetime experiment. Under the optimized experimental conditions, linear calibration curves for detecting CTC/MTC were obtained with a limit of detection of 12.91/12.10 ng mL−1. The contents of CTC/MTC in milk, tangerine, beef and pork samples were detected. The recoveries of CTC/MTC were satisfactory. The established method had good analytical performance and can be used for the detection of more actual samples.

Dual-mode photoelectrochemical radar based on CdS quantum dot and Ce-MOF for detection of low-abundance disease-associated proteins

Herein, we developed a convenient and versatile dual-mode electrochemiluminescence (ECL) and photoelectrochemistry (PEC) sensing radar for the detection of Prostate-specific antigen (PSA), which has important implications for detection of low-abundance disease-associated proteins. Cerium-based metal-organic framework (Ce-MOFs) were firstly modified on the electrode, showing well ECL and PEC property. In particular, a unique multifunctional Au@CdS quantum dots (QDs) probe loaded numerous QDs and antibody was fabricated, not only displaying strong ECL and PEC signals, but also having specific recognition to PSA. After the signal probe was linked to the electrode by immune reaction, much amplified signals of ECL and PEC were generated for double-mode detection of PSA. Therefore, this work proposed a multifunctional Au@CdS QDs signal probe with excellent ECL and PEC performance, and developed an ultrasensitive photoelectric biosensing platform for dual-mode detection, which provides an effective method for health monitoring of cancer patients.

Preparation of water-soluble cadmium sulfide quantum dots with narrow small-size distribution by controlling hydrodynamic cavitation device parameters

With the increasingly broad application of quantum dots in many fields, how to further improve the performance of quantum dots in various aspects has become an urgent problem to be solved. In this study, hydrodynamic cavitation (HC) technology was applied for the first time in the preparation of quantum dots. Specifically, cadmium sulfide quantum dots (CdS QDs) with small particle size, narrow distribution, high concentration and large Stokes shift are prepared. Firstly, CdS precipitation was obtained in an aqueous solvent, using cadmium nitrate tetrahydrate (Cd(NO3)2·4H2O) and sodium sulfide nonahydrate (Na2S·9H2O) as Cd and S sources, respectively. Subsequently, CdS QDs were formed from top to bottom through hydrodynamic cavitation reactor, which generates high temperature, high pressure, high-speed jets, shear forces, and shock waves. In summary, the intrinsic advantages of HC technology offer a new opportunity for manufacturing large-scale quantum dots with superb performance.

In-situ synthesis of CdS and Ag2S quantum dots in poly(diallyldimethylammonium chloride) gels

In this study, we proposed a hybridization method for polymer and quantum dots (QDs) by directly forming QDs in polymer gel; this method was completely different from conventional methods such as mixing and encapsulation. QDs were fabricated by reacting metal ions in solution with sulfide ions adsorbed in a gel made from poly(diallyldimethylammonium chloride) (PDADMAC), a cationic polymer. CdS and Ag2S QDs were successfully fabricated in PDADMAC gel for in situ synthesis, and visible light (534 nm) and NIR (1070 nm) emissions were observed in PDADMAC gel containing CdS and Ag2S QDs, respectively. We also discussed the formation mechanism of QDs in the gel considering the mesh size of polymer networks in PDADMAC gel.

Green Synthesis of Indole-pyrazole-capped Cadmium Sulphide Quantum Dots and Evaluation of Their Cytotoxicity Activity and Protein Interaction

Green Synthesis of Indole-pyrazole-capped Cadmium Sulphide Quantum Dots and Evaluation of Their Cytotoxicity Activity and Protein Interaction