Manganese-doped Zinc Sulfide Research Articles

Determination of Lead (II) by Phosphorescence Using Manganese-Doped Zinc Sulfide Quantum Dots

Photoluminescence enhancement provides an effective way to improve the performance of quantum dots. In this study, lead(II) determination was demonstrated based on phosphorescence enhancement using 1-thioglycerol-capped Mn-doped ZnS quantum dots. Under the optimized conditions, good linear correlations were obtained for Pb2+ from 10.00 to 5000 nM and 0.05000 to 100.0 mM with correlation coefficients of 0.9997 and 0.9979 and a detection limit of 2.56 nM. The method demonstrates good linearity and selectivity, suitable sensitivity, easy operation, and the determination of Pb2+ in Chinese herbal medicine.

Improved Persistence of Bacteriophage Formulation with Nano N-Acetylcysteine-Zinc Sulfide and Tomato Bacterial Spot Disease Control.

Bacteriophages are biocontrol agents used to manage bacterial diseases. They have long been used against plant pathogenic bacteria; however, several factors impede their use as a reliable disease management strategy. Short-lived persistence on plant surfaces under field conditions results mainly from rapid degradation by exposure to ultraviolet (UV) light. Currently, there are no effective commercial formulations that protect phages from UV. The phage ΦXp06-02-1, which lyses strains of the tomato bacterial spot pathogen Xanthomonas perforans, was mixed with different concentrations of the nanomaterial N-acetylcysteine surface-coated manganese-doped zinc sulfide (NAC-ZnS; 3.5 nm). In vitro, NAC-ZnS at 10,000 μg/ml formulated phage, when exposed to UV for 1 min, provided statistically equivalent plaque-forming unit (PFU) recovery as phages that were not exposed to UV. NAC-ZnS had no negative effect on the phage's ability to lyse bacterial cells under in vitro conditions. NAC-ZnS reduced phage degradation over time in comparison with the nontreated control, whereas N-acetylcysteine-zinc oxide (NAC-ZnO) had no effect. In fluorescent light, without UV exposure, NAC-ZnO-formulated phages were more infective than NAC-ZnS-formulated phages. The nanomaterial-phage mixture did not cause any phytotoxicity when applied to tomato plants. Following exposure to sunlight, the NAC-ZnS formulation improved phage persistence in the phyllosphere by 15 times compared with nonformulated phages. NAC-ZnO-formulated phage populations were undetectable within 32 h, whereas NAC-ZnS-formulated phage populations were detected at 103 PFU/g. At 4 h of sunlight exposure, NAC-ZnS-formulated phages at 1,000 μg/ml significantly reduced tomato bacterial spot disease severity by 16.4% compared with nonformulated phages. These results suggest that NAC-ZnS can be used to improve the efficacy of phages for bacterial diseases.

Development of inexpensive device for methanol detection in hand sanitizer gel using manganese-doped zinc sulfide quantum dots modified by N-methylpolypyrrole

A method for methanol detection by an inexpensive device using a nanomaterial modified by N-methylpolypyrrole (NMPPY) has been developed. Manganese-doped zinc sulfide quantum dots (Mn/ZnS-QDs) were synthesized and then characterized by a fluorescence spectrophotometer to study their spectroscopic properties. Mn/ZnS-QDs were modified with NMPPy and studied by digital-image colorimetry to optimize conditions for methanol detection. A 2 mL of 3000 mg∙L–1 Mn/ZnS-QDs modified with 300 μL of 1000 mg∙L-1 of NMPPy was chosen to be a detecting reagent for methanol determination. Under the optimum conditions, the linear range was found to be 2%v/v to 50%v/v of methanol with R-square of 0.9434 and the sensitivity of 3.569 ´ 10–3 (%v/v)-1, whilst the limit of detection (LOD) was 19.5%v/v. The selectivity of this method was also studied with several solvents; it was proven selective for methanol. Furthermore, a prototype device with simple and inexpensive has been created. The analytical performances were studied; the linearity of methanol detection was found in the range of 20%v/v to 80%v/v with R-square of 0.9918 and the sensitivity of 3.38 ´ 10-3 (%v/v)-1. Finally, the newly developed device was applied to analyze samples of hand sanitizer gel by digital-image colorimetry with acceptable results.

Antibacterial studies of ZnO and silica capped manganese doped zinc sulphide nanostructures

Antibacterial studies of ZnO and silica capped manganese doped zinc sulphide nanostructures

Chemical Synthesis, Morphology, and Optical Properties of Manganese-Doped Zinc Sulfide Films

Chemical Synthesis, Morphology, and Optical Properties of Manganese-Doped Zinc Sulfide Films

Molecular Imprinted ZnS Quantum Dots-Based Sensor for Selective Sulfanilamide Detection.

Combining molecular imprinted polymers and water-soluble manganese-doped zinc sulfide quantum dots (Mn2+: ZnS QDs), a new molecule imprinted polymers-based fluorescence sensor was designed. The molecule imprinted quantum dots (MIP@QDs) were constructed by coating molecular imprinted polymers layer on the surface of ZnS: Mn2+ QDs using the surface molecular imprinting technology. The developed MIP@QDs-based sensor was used for rapid and selective fluorescence sensing of sulfanilamide in water samples. The binding experiments showed that the MIP@QDs has rapid fluorescent responses, which are highly selective of and sensitive to the detection of sulfanilamide. The respond time of the MIP@QDs was 5 min, and the imprinting factor was 14.8. Under optimal conditions, the developed MIP@QDs-based sensor shows a good linearity (R2 = 0.9916) over a sulfanilamide concentration range from 2.90 × 10−8 to 2.90 × 10−6 mol L−1, with a detection limit of 3.23 × 10−9 mol L−1. Furthermore, the proposed MIP@QDs-based sensor was applied to the determination of sulfanilamide in real samples, with recoveries of 96.80%–104.33%, exhibiting good recyclability and stability. Experimental results showed that the prepared MIP@QDs has the potential to serve as a selective and sensitive sensor for the fluorescence sensing of sulfonamides in water samples.

Microwave-assisted synthesis and characterization of undoped and manganese doped zinc sulfide nanoparticles

Undoped and Mn-doped ZnS nanocrystals were produced by the microwave-assisted solvothermal method and characterized by X-ray diffraction, photoluminescence spectroscopy and scanning electron microscopy with energy-dispersive X-ray spectroscopy. All samples have the cubic zinc blende structure with the lattice parameter in the range of a = 5.406–5.411 Å, and the average size of crystallites is in the range of 6–9 nm. These nanoparticles agglomerate and form large grains with an average size of up to 180 nm. The photoluminescence of the undoped ZnS sample shows a broad emission band located at 530 nm, attributed to the defects at the surface of nanoparticles. In all Mn-doped samples, the emission peak at 598 nm was observed assigned to the characteristic forbidden transition between excited (4T1) and ground (6A1) levels of Mn2+. Synchrotron radiation X-ray absorption spectroscopy at the Zn and Mn K-edges combined with reverse Monte Carlo (RMC) simulations based on the evolutionary algorithm confirms that manganese ions substitute zinc ions. However, the difference in the ion sizes (R(Mn2+(IV)) = 0.66 Å and R(Zn2+(IV)) = 0.60 Å) is responsible for the larger interatomic distances Mn–S (2.40(2) Å) compared to Zn–S (2.33(2) Å). The static structural relaxations in ZnS:Mn nanoparticles are responsible for the large values of the mean-square displacements factors for Zn, S and Mn atoms obtained by RMC simulations.

Enzyme Nanoscale Interactions with Manganese Zinc Sulfide Give Insight into Potential Antiviral Mechanisms and SARS-CoV-2 Inhibition.

Recent interest in nanomedicine has skyrocketed because of mRNA vaccine lipid nanoparticles (LNPs) against COVID-19. Ironically, despite this success, the innovative nexus between nanotechnology and biochemistry, and the impact of nanoparticles on enzyme biochemical activity is poorly understood. The studies of this group on zinc nanoparticle (ZNP) compositions suggest that nanorod morphologies are preferred and that ZNP doped with manganese or iron can increase activity against model enzymes such as luciferase, DNA polymerase, and β-galactosidase (β-Gal), with the latter previously being associated with antimicrobial activity. SARS-CoV-2 encodes several of these types of oxido-reductase, polymerase, or hydrolase types of enzymes, and while metamaterials or nanoparticle composites have become important in many fields, their application against SARS-CoV-2 has only recently been considered. Recently, this group discovered the antiviral activity of manganese-doped zinc sulfide (MnZnS), and here the interactions of this nanoparticle composite with β-Gal, angiotensin converting enzyme (ACE), and human ACE2 (hACE2), the SARS-CoV-2 receptor, are demonstrated. Low UV, circular dichroism, and zeta potential results confirm their enzyme interaction and inhibition by fluorometric area under the curve (AUC) measurements. The IC50 of enzyme activity varied depending on the manganese percentage and surface ranging from 20 to 50 μg/mL. MnZnS NPs give a 1–2 log order inhibition of SARS-CoV-2; however, surface-capping with cysteine does not improve activity. These data suggest that Mn substituted ZNP interactions to hACE2 and potentially other enzymes may underlie its antiviral activity, opening up a new area of pharmacology ready for preclinical translation.

Manganese-doped zinc sulfide binary nanostructures as binder-free electrode materials for supercapattery

Manganese-doped zinc sulfide binary nanostructures as binder-free electrode materials for supercapattery

Fluorescent sensor based on thiourea capped Mn doped ZnS quantum dots for the sensing of Cu2+ ions in water

In the present study the utilization of a simple, rapid, and highly effective “turn-off” fluorescent sensor based on thiourea capped manganese doped zinc sulphide quantum dots for the detection of Cu2+ ions in water is described for the first time. The quantum dots are prepared by a simple and facile chemical precipitation method. The developed quantum dots are characterized by UV–vis., FT-IR, photoluminescence, XRD, and TEM techniques. The doping by manganese is confirmed by a peak at 598 nm in the PL spectrum. The sensor exhibit high sensitivity and selectivity towards copper ion at pH 9 with a limit of detection of 20.75 nM. The obtained results are also reasonable in real sample analysis.

Field-induced light emission from a close-packed Mn-doped ZnS quantum-dot layer in an alternate-current thin-film electroluminescent configuration

By exploiting the configuration of an alternate-current thin-film electroluminescent device, we observe the emission of light from a close-packed spin-cast layer of manganese-doped zinc sulfide nanoparticles (NPs), sandwiched between two dielectric layers, induced by the application of an AC voltage. By means of a microwave-assisted polyol synthesis, we are able to obtain high-crystalline surfactant-free NPs, which can be closely packed in the emitting layer, allowing an emission mechanism due to local charge creation and transport, instead of the typical impact-excitation process. This synthesis route allows us to get rid of a bulk semiconductor layer, implying that far less expensive routes for the active layer deposition such as spin coating, inkjet printing, or spray coating can be used. Our work allows us to get a deeper insight into the role played by the NP structure on the charge-transfer mechanism behind light emission and paves the way to a new generation of non-toxic quantum-dot-based displays.

Manganese-doped zinc sulfide microspheres for improved electrocatalytic sensing ability toward carbendazim in food samples

The fungicide carbendazim (CBZ) is generally used to make crops more resistant to pathogens. However, because pesticide residues due to overuse have polluted food products, they have become a global public health problem. Ultralow-level determination of CBZ in food products has become crucial for health protection and environmental safety; however, the task remains challenging. In this study, a composite containing Mn-doped ZnS was prepared with a facile reflux approach. Compared with conventional ZnS electrodes and GCEs, the hierarchical Mn-doped ZnS microspheres with abundant edge/defect sites improve the interface charge transfer capacity, thereby resulting in a lower Rct. The Mn-doped ZnS-GCE displays excellent electrocatalytic sensing ability for CBZ in 0.05 M PBS at a higher anodic current and low sensing potential compared to those of other ZnS electrodes and GCEs. The square wave voltammetry (SWV) results confirm that the Mn-doped ZnS-GCE has a more comprehensive linear working range (5–120 nM) for CBZ, and the measured ultralow detection limit for CBZ is 0.03 nM. Interestingly, we investigated the real-time applicability of the Mn-doped ZnS-GCE for the precise identification of spiked CBZ in lemon wash water samples, tomato sauce, and orange juice samples with satisfactory recovery.

Vitamin B6 cofactor-directed fluorescent “turn-on” detection of alkaline-phosphatase activity using bovine serum albumin-functionalized Mn–ZnS quantum dots

Alkaline phosphatase (ALP) activity was detected using bovine serum albumin (BSA)-functionalized manganese-doped zinc sulfide (Mn–ZnS) quantum dots (QDs), and the phosphate substrate was the vitamin-B6 cofactor pyridoxal 5′-phosphate (PLP).

Photodegradation Process of Organic Dyes in the Presence of a Manganese-Doped Zinc Sulfide Nanowire Photocatalyst.

Zinc sulfide (ZnS) nanowires represent a promising candidate in many fields, including optoelectronics and photocatalysis because of their advantages such as excellent optical properties, chemical stability and an easy-scalable simple synthesis method. In this study, an energy-friendly microwave radiation process was used to develop the single-step, solvothermal process for the growth of manganese-doped zinc sulfide (ZnS) and undoped nanocrystals (NCs) in the forms of nanowires using two short amines as a stabilizer, e.g. ethylenediamine and hydrazine, respectively. ZnS nanowires doped with Mn atoms show absorbance in UV and in the visible region of the spectrum. The photocatalytic degradation of rhodamine B in the presence of Mn-doped and undoped ZnS nanocrystals illuminated with only a 6-W UV lamp has been comprehensively studied. The effect of Mn doping and the presence of a nanocrystal stabilizer on the degradation process was determined. It was found that the efficiency of a photocatalytic degradation process was strongly affected by both factors: the doping process of nanowires with Mn2+ atoms and the attachment of ligands to the nanocrystal surface.

Synthesis and characterization of 2-mercaptoethanol-capped manganese-doped zinc sulfide quantum dots-embedded molecularly-imprinted membranes

The objective of this study is to synthesize QD-embedded molecularly imprinted membranes (MIMs) with 2-mercaptoethanol-capped manganese-doped zinc sulfide quantum dots (ME-capped Mn-doped ZnS QDs) through chemical precipitation followed by surface molecular imprinting. For the synthesis of the MIMs, the weight of ME-capped Mn-doped ZnS QDs was first manipulated, followed by their characterization through transmission electron microscopy (TEM), zeta potential, hydrodynamic particle size, particle size distribution, and Fourier-transform infrared spectroscopy (FTIR). The resultant MIM was characterized by fluorescence intensity and showed an emission peak of 600 nm with an excitation wavelength of 300 nm. Besides, increments in QDs were found to elevate the fluorescence intensity of the MIM, contributing to an improved fluorescence quantum yield. This article indicates that molecularly-imprinted QD-based sensors offer promising biomedical potential in diagnoses and treatment.

Unraveling the anomalous mechanoluminescence intensity change and pressure-induced red-shift for manganese-doped zinc sulfide

Mechanoluminescence (ML) has promising applications such as stress sensors and many other fields, which raises intensive research attention and enthusiasms in the past few decades. However, accurate characterizations of the ML process with high temporal and spectral resolution remain a considerable challenge for the current scientific community. Here, an advanced ML characterization system based on the dynamic diamond anvil cell (dDAC) is developed to achieve flexible modulations of ML performances. Upon compression, the ML spectra of manganese-doped zinc sulfide (ZnS:Mn) show a large red-shift (~45 nm) and a volcano-trend of the ML intensity, where the cumulative ML intensity is solely dependent on the pressure change. DFT calculations identify the coupling of Mn-doping and surface vacancies is playing a crucial role in contributing to the improvement of ML through the band offset. The suppression of the vacancies formation on the surface by the applied pressure over 4 GPa leads to the decreases of the ML intensity. This work provides a brand new ML color and intensity tuning strategy and offers a promising method to explore the ML mechanism.

Enhancement of photo luminescent and magnetic properties of surface modified zinc sulphide nanoparticles by manganese doping

In the current paper we have reported the structural, optical and magnetic properties of manganese doped (1% to 10%) zinc sulphide nanoparticles synthesised by simple chemical co-precipitation method at room temperature. The crystal structure of the synthesised nanoparticles has been confirmed by X-ray diffraction and the average crystallite size calculated by Scherrer formula was about 3.0 nm. A slight quenching in the crystallite size with the doping was also observed. The FESEM images showed spherical shape particles with uniform size distribution. The elemental composition of pure and manganese doped zinc sulphide was confirmed by EDAX attached to FESEM. The UV-Vis spectra has an absorption edge at 321 nm with sharp fall in the absorption confirming the particles of uniform size distribution with no shift in the absorption edge with the doping. The band gap widening was observed (4.4 eV) and the particle size (3.4 nm) calculated was by effective mass approximation. The photoluminescence spectra has wide emission spectra with the peaks at 397 nm, 414 nm and 487 nm with increase in the intensity with the doping concentration giving a peak at 1% of doping and decrease in emission intensity after that. The hysteresis curve shows the ferromagnetism and the saturation magnetisation increases with the doping concentration.

Optical Studies of Organically Functionalized Mn doped ZnS Quantum Dots

Organically functionalized manganese doped zinc sulfide (ZnS/Mn) quantum dots were prepared by simple chemical method with polypyrrole (PPy) used as a capping agent. Prepared quantum dots were characterized with Fourier transform infrared spectroscopy (FTIR), high resolution transmission electron microscopy (HR-TEM), X-ray diffraction microscope (XRD), UV-visible spectroscopy and photoluminescence spectroscopy. Crystalline size of PPy capped ZnS/Mn quantum dots for various concentrations of PPy were approximate 2 nm as analyzed by XRD and TEM analysis. The absorption spectra revealed the occurrence of a blue shift in the peak of absorption and an increase in the band gap value due to the quantum confinement effect. FTIR spectroscopy confirmed that shifting of broad peak at 2335.8 cm–1 was due to S-H stretching vibrations, which confirmed interaction of hydrogen and sulphur in ZnS/Mn/PPy nanocomposites. Uncapped ZnS/Mn and PPy capped ZnS/Mn quantum dots reveal the effective photoluminescence emission spectra in the range of 300-700 nm. With increase the value of capping agent in ZnS/Mn quantum dots, photoluminescence spectra going to red shifting. The photoluminescence properties of the organically functionalized ZnS nanoparticles are favourable for the application in optoelectronic devices.

Manganese-Doped Zinc Sulfide Microspheres for Improved Electrocatalytic Sensing Ability Toward Carbendazim in Food Samples

Manganese-Doped Zinc Sulfide Microspheres for Improved Electrocatalytic Sensing Ability Toward Carbendazim in Food Samples

Absence of Mn emission in MnxZn(1-x)S thin films grown by spray pyrolysis technique

In the present investigation, the effect of manganese (Mn) dopant on zinc sulfide (ZnS) thin films used for blue light emitting diode was studied. The basic studies on the structural and morphological properties showed good crystallinity up to 2 at % Mn concentration. Samples were studied for the presence of defects using models of Urbach energy and near-edge absorptivity ratio (NEAR). Upon manganese doping, enhancement in the blue emission (in the wavelength region ~ 400 nm) was observed, and interestingly, the Mn related orange emission was not observed. Here, we explained the possible reasons for the suppression of this signature orange emission. Present work is compared with various other reports on manganese doped zinc sulfide (MnxZn(1-x)S). The properties of the MnZnS films were characterized using spectroscopic techniques like static and time resolved photoluminescence (TRPL) along with X-Ray photoelectron spectroscopy (XPS). Measured lifetime of defects was in several hundreds of pico-second. From the spectroscopic characterizations, anomalous behavior of Mn related defects in the MnZnS thin films were explained. An extensive study on XPS of the prepared MnxZn(1-x)S thin film gave greater insight to the possible mechanism for this anomalous luminescence behavior.