Manganese-doped Zinc Sulfide Research Articles

Triple-dimensional spectroscopy combined with chemometrics for the discrimination of pesticide residues based on ionic liquid-stabilized Mn-ZnS quantum dots and covalent organic frameworks

Manganese-doped zinc sulfide quantum dots (Mn-ZnS QDs) are promising candidates for multi-channel sensing analysis due to their multi-dimensional optical properties. In this study, we integrated amino-silane and ionic liquid co-modified Mn-ZnS QDs and covalent organic frameworks (COFs) into optosensing nanoparticles to provide triple-dimensional optical response signals and combined them with chemometrics for the analysis of multiple pesticide residues. Through the exploration and optimization of a series of conditions, fluorescence, room temperature phosphorescence, and ultraviolet−visible combined with chemometrics were used for the discrimination and recognition of multiple pesticide residues in fruits and vegetables. The ionic liquid of 1-vinyl-3-ethylimidazolium tetrafluoroborate was used to modify Mn-ZnS QDs to improve the optical response and enrichment of pesticide adsorption sites, which were also synergistically enhanced by the COF support. This is a potential method to discriminate pesticides efficiently and enables fast and reliable analysis of pesticides in the agricultural and food industries.

Efficient color manipulation of zinc sulfide-based mechanoluminescent elastomers for visualized sensing and anti-counterfeiting

Elastomeric mechanoluminescence (EML) materials capable of generating luminescence during elastic deformation are promising for many practical applications in modern technologies. Among them, copper- or manganese-doped zinc sulfide (ZnS) in a polydimethylsiloxane (PDMS) matrix has emerged as the most efficient EML material by virtue of its intense EML intensity. However, it is insufficient to trigger abundant electron entrapments and activate high energy blue emission under weak mechanical stimuli (<1k Hz) due to the softness of the composite. The limited range of available emission spectra has greatly constrained its applications. In this case, an efficient approach is developed for expanding EML emission through incorporation of long afterglow phosphors. The as-fabricated composites show efficient and tunable EML emissions covering three primary colors of red-green-blue (RGB) even under extremely weak mechanical stimuli (1 Hz; ε = 10%). Furthermore, various application prospects of a series of proof-of-concept optical devices such as handwriting input, gesture sensing, and encrypted anti-counterfeiting are successively demonstrated. This feasible technique provides a general platform to broaden color expression under weak mechanical stimuli, which could inspire the fabrication of various novel applications.

Effects of sintering temperature and phase transition on the photoluminescence and triboluminescence of manganese doped zinc sulfide

Abstract In this work, manganese doped zinc sulfide (ZnS: Mn2+) samples were synthesized by a solid-state method under various sintering temperature. With the increase of temperature, ZnS: Mn2+ was gradually evolved from zinc blende to wurtzite phase with particle size reduced. Further increasing the sintering temperature of wurtzite ZnS: Mn2+ could lead to a preferred orientation of crystal phase. The above physical structure evolutions aroused remarkably changes on the luminescent properties of ZnS: Mn2+, and the effects of sintering temperature and phase transition were investigated. The results suggested that ZnS: Mn2+ of wurtzite phase was more efficient for both photoluminescence and triboluminescence. This should be attributed to not only the enhanced excitation efficiency and piezoelectricity, but also the increased carrier density in traps and the beneficial kinetic order of ZnS: Mn2+ in wurtzite phase. The photoluminescence and triboluminescence of ZnS: Mn2+ showed different spectral shift behaviors along with the crystal phase variation, suggesting that they possessed different energy transfer pathways and thus the distinct dependence on crystal field and band gap. The presented research on the luminescent behaviors of ZnS: Mn2+ with varied crystal phase, especially for the content regarding to triboluminescence, should be useful to further guide the design and optimization of ZnS-based luminescent materials as well as the full reveal of its luminescent mechanisms.

Dopamine-induced photoluminescence quenching of bovine serum albumin-capped manganese-doped zinc sulphide quantum dots.

The direct detection of dopamine (DA) in human body fluids is a great challenge for medical diagnostics of neurological disorders like Parkinson's disease, Alzheimer's disease, senile dementia, and schizophrenia. In this work, a simple and turn off luminescence sensing of DA based on bovine serum albumin (BSA)-capped manganese-doped zinc sulphide quantum dots (Mn:ZnS/BSA QDs) is developed. The Mn:ZnS/BSA QDs were synthesized by a chemical co-precipitation method. Due to the special interaction of DA with BSA and metal ions, Mn:ZnS/BSA QDs can serve as an effective sensing platform for DA. The luminescence of Mn:ZnS/BSA QDs decreased linearly with increasing concentration of DA in the range from 6.6 to 50.6nM. The limit of detection is 2.02nM. The driving force for the luminescence quenching is partly provided by ground-state complex formation of QDs with DA. The photo-induced electron transfer from the conduction band of QDs to oxidized dopamine (quinone) also favors quenching. The Mn:ZnS/BSA QDs are barely interfered with by other competing biomolecules except catecholamine neurotransmitter like epinephrine. Moreover, this method is used in the analysis of DA-spiked human serum and human urine samples and good recovery percentages are found. To assess the utility of the developed sensor, paper strip assay was also successfully conducted. Graphical abstract.

Optical and magnetic properties of manganese doped zinc sulphide: density functional theory approach

In this work, electronic, optical and the magnetic properties of cubic ZnS doped with the transition metal (TM) Mn were numerically studied using the density functional theory code WIEN2K. The investigated concentrations included the compositional parameters x of 6.25%, 12.5% and 25% in Zn1-xMnxS. Computed electronic band structures and density of states (DOS) showed a half-metallic, ferromagnetic behavior with a direct band gap. The energy gap was found to increase with dopant concentration. Furthermore, optical properties such as the imaginary (ε2) and the real (ε1) part of the dielectric function, reflection, refractive index, absorption coefficient and optical conductivity show new transition peaks appear with Mn doping. The obtained results make the Zn1-xMnxS compound a promising candidate for spintronics devices.

Silica-Coated Mn-Doped ZnS Nanocrystals for Cancer Theranostics

Doped nanocrystals such as manganese-doped zinc sulfide (ZnS:Mn) are useful nanomedicine probes for cancer cell labeling and anticancer drug delivery. However, the synthesis and retention of fluorescence of these nanocrystals is highly indispensable for efficient cell theranostics. Herein, we report a modified synthesis of highly fluorescent hydrophobic ZnS:Mn nanocrystals with the advent of dual ligands. Our results demonstrate that the alkylamine ligand with the carbon chain length of C18 promotes the diffusion of Mn from the surface into the interior of ZnS nanocrystals. Optical measurements show that the quantum yield of Mn (QYMn) can reach as high as 80% in the presence of a dual ligand combination of oleylamine–octadecylamine because of the increased probability of 4T1 → 6A1 emission, originating from the energy transfer of ligated nanocrystals. These doped nanocrystals after ligand exchange of organic ligands with glutathione exhibited a high retention of quantum yield (QY: ∼50–60%), and further coating with silica showed the QY of ∼35–40%. Finally, we show the application of these doped nanocrystals for cancer theranostics such as HeLa cell labeling and anti-cancer drug delivery.

One Pot Aqueous Synthesis of L-Histidine Amino Acid Capped Mn: ZnS Quantum Dots for Dopamine Sensing

Background: Mn doped ZnS is selected as the right element which is prominent among quantum dot for its high luminescent and quantum yield property and also non toxicity while comparing with other organometallic quantum dot synthesized by using different capping agents. Methods: An interesting observation based on colorimetric sensing of dopamine using manganese doped zinc sulfide quantum dot is discussed in this study. Mn doped ZnS quantum dot surface passivated with capping agents such as L-histidine and also in polymers like chitosan, PVA and PVP were studied and compared. The tunable fluorescence effect was also observed in different polymers and amino acid as capping agents. Optical characterization studies like UV-Visible spectroscopy and PL spectroscopy have been carried out. The functional group modification of Quantum dot has been analyzed using FTIR and size and shape analysis was conducted by using HRTEM image. Result: The strong and broad peak of FTIR in the range of 3500-3300 cm-1 confirms the presence of O-H bond. It is also observed that quenching phenomena in the luminescent peak are due to weaker confinement effect. The average size of the particle is shown to be around 4-5 nm. Changes in color of the quantum dot solution from transparent to dark brown has been due to the interaction with dopamine. Conclusion: Finally, L-Histidine amino acid capped Mn:ZnS shows better results in luminescence and size confinement properties. Hence, it was chosen for dopamine sensing due to its colloidal nature and inborn affinity towards dopamine, a neurotransmitter which is essential for early diagnosis of neural diseases

XAS Microstructure Analysis of Manganese Doped Zinc Sulphide Nanophosphor

This paper reports wet chemical synthesis of Manganese doped Zinc Sulphide Nanophosphors capped with polyvinyl alcohol (PVA) while varying the concentrations of the dopant and capping agent to explore the optoelectronic and microstructural properties. Optical and morphological comparative studies reveal strongest room temperature orange luminescence (∼591 nm) of 10% dopant concentration with 2% capping agent in the ZnS host lattice and irregularly spherical nanoparticles formation (∼29 nm). Further, structural and elemental study of the sample reveals uncontaminated hexagonal wurtzite nanoparticles with least structural distortion due to dopant induced substitutional defect. The XANES and EXAFS microstructure analysis confirm the creation of substitutional defect and comparable Zn-S and Mn-S bond lengths such that Mn luminescent centers are created. Hence, the detailed study of the material indicates its high efficiency, proving its ability to be explored as a strong candidate for Mn: ZnS based UV Photodetector devices.

Application of Zinc Sulfide Quantum Dots for Optical Sensing

The luminescent sensory systems based on manganese-doped zinc sulfide quantum dots were developed for aqueous environment monitoring. The structural, optical and sensory characteristics of quantum dots were investigated. The mechanism of ZnS:Mn2+ interaction with methane in the aqueous media, as well as factors that have a primary influence on the formation of the sensory response in the reaction with methane, were determined.

Biogenic Control of Manganese Doping in Zinc Sulfide Nanomaterial Using Shewanella oneidensis MR-1.

Bacteria naturally alter the redox state of many compounds and perform atom-by-atom nanomaterial synthesis to create many inorganic materials. Recent advancements in synthetic biology have spurred interest in using biological systems to manufacture nanomaterials, implementing biological strategies to specify the nanomaterial characteristics such as size, shape, and optical properties. Here, we combine the natural synthetic capabilities of microbes with engineered genetic control circuits toward biogenically synthesized semiconductor nanomaterials. Using an engineered strain of Shewanella oneindensis with inducible expression of the cytochrome complex MtrCAB, we control the reduction of manganese (IV) oxide. Cytochrome expression levels were regulated using an inducer molecule, which enabled precise modulation of dopant incorporation into manganese doped zinc sulfide nanoparticles (Mn:ZnS). Thereby, a synthetic gene circuit controlled the optical properties of biogenic quantum dots. These biogenically assembled nanomaterials have similar physical and optoelectronic properties to chemically synthesized particles. Our results demonstrate the promise of implementing synthetic gene circuits for tunable control of nanomaterials made by biological systems.

A novel approach to the synthesis of Zn2SiO4:Mn luminescent nanoparticles

In this study, manganese doped zinc sulfide nanoparticles with luminescence properties (Mn2+ ions) were synthesized together with silica-aerogel particles. The effect of temperature variations on the optical properties of the composite was investigated. X-ray diffraction patterns (XRD) showed the transformation of ZnS (sphalerite) to Zn2SiO4 (willemite) after heat treatment. Both silica aerogel and as-deposited SiO2–ZnS:Mn nanocomposites contained nanoparticles with emission wavelength of up to 30 nm. The heat treatment caused an obvious increase in the particle size to nanometer scale. Photoluminescence (PL) spectra revealed that ZnS:Mn possesses an emission peak at 590 nm, which was quenched by increasing the Mn content above 2.5% mol. In the as-deposited SiO2–ZnS:Mn spectra, an extra peak in the blue region was observed which is related to the silica structure. However, the heat treatment led to the appearance of strong green emission peak at 527 nm due to the formation of willemite which was quenched at higher temperatures due to the change of structure from willemite to tridymite. Finally, two luminescent inks were produced by as-deposited and heat treated SiO2–ZnS:Mn nanocomposites in water-based solvents as security inks.

Enhanced optoelectrical properties of Mn-doped ZnS films deposited by spray pyrolysis for ultraviolet detection applications

In the present study, chalcogenide manganese-doped zinc sulfide (Mn-doped ZnS) films were deposited by spray pyrolysis method at various concentration of Mn2+ ions (0 ≤ Mn2+ ≤ 15 mol%) and the effect of Mn-doping concentration on the photodetection characteristics of the films was investigated. The phase structure, chemical composition and surface morphology of the films were characterized by grazing incidence X-ray diffraction, energy dispersive spectroscopy, and field emission scanning electron microscopy. The results confirmed the stable zinc blende phase, nanocrystalline structure and the nearly stoichiometric ratio of elements, as well as uniform and well adherent of the films to the substrates. The Mn2+ concentration-dependent optical and electrical properties of the films were investigated using ultraviolet-visible spectroscopy, photoluminescence, and current-voltage measurements. The photoluminescence spectra exhibited two emission peaks located at ultraviolet (UV) and orange regions. The optical density, optical band gap energy, and Urbach energy were also evaluated. By increasing Mn2+ content, a slight decrease in the optical band gap energy was observed, while the Urbach energy broadened, gradually. Therefore, a linear relationship between the band gap energy and Urbach energy was found. Moreover, the relevance of the steepness parameter and electron-phonon interaction was studied. The optoelectrical analysis in the dark and under light irradiation with different wavelengths revealed the visible-blind nature of the samples. The electrical characteristics of the fabricated UV detectors featured tremendous photocurrent gain and photo-response switching behavior to UV-A irradiation.

Study the Antifungal Activity of ZnS:Mn Nanoparticles Against Some Isolated Pathogenic Fungi

An aqueous chemical reaction has been used to prepare antifungal ZnS: Mn nanostructures, from manganese chloride, zinc acetate and thioacetamide in aqueous solution. The nanoparticle size has been controlled using thioglycolic acid as a capping factor. The major feature of the ZnS:Mn nanoparticles of average diameter ∼ 2.73 nm is that possible preparing the sample from sources non-toxic precursors. The manufactured ZnS:Mn nanoparticles were identified and characterized to investigate the structure, morphology, composition of components of the nanoparticles and optical properties using (XRD, SEM, EDS and UV-Vis spectroscopy) techniques respectively. The agar dilution mechanism used to evaluate of the antifungal activity using ZnS:Mn nanoparticles which showed an efficient antifungal activity against four fungal models Aspergillus fumigatus, Aspergillus falvus, Trichophyton mentagrophyte, and Microsporum audonii the inhibition increase with the increase of nanoparticle concentration. The antifungal property of manganese doped zinc sulphide nanoparticles creates from the interaction between nanoparticles and water led to generation the interactive oxygen species. Perturbation of the cell membranes due to the existence of Zn ions and S affecting on inhibition rate. the study aimed to evaluation the Antifungal Activity of ZnS:Mn Nanoparticles Against Some Isolated Pathogenic Fungi.

Manganese Doped Zinc Sulfide Quantum Dots as Efficient Photocatalyst for Dye Decolorization

A simple aqueous based synthesis technique at room temperature was performed for preparation of pure and manganese (Mn2+) doped ZnS quantum dots in the presence of glutathione as the capping agent. Under UV-excitation quantum dots show photoluminescence bands at 2.13 and 3.0 eV corresponded to Mn2+ and intrinsic ZnS emission respectively. ZnS quantum dots were used as the photocatalyst to remove organic dyes in aqueous solution, with methylene blue as a model dye. The influence of the Mn2+ concentration on the dye degradation efficiency was studied. The highest photocatalytic degradation rate of methylene blue was obtained for ZnS quantum dots in glutathione shell doped with 0.125 at % of Mn2+.

Luminescent Methane Sensor Based on Energy Transfer from ZnS:Mn2+ Quantum Dots to Analyte Molecule

Manganese-doped zinc sulfide quantum dots were synthesized by chemical precipitation in an aqueous solution in the presence of glutathione as the capping agent. Obtained samples show dual emission band with maximums at 2.11 eV (Mn2+) and about 3.1 eV (intrinsic defects of ZnS QDs). Under exposure to methane in the concentration range from 100 to 2000 ppm the ZnS:Mn2+ emission spectrum is changed significantly. It was shown, the luminescent sensor response occurs due to photoinduced electron transfer from QDs to methane molecule resulting in QD luminescence quenching and luminescence lifetime decreasing.

Photoluminescence sensing of bilirubin in human serum using l-cysteine tailored manganese doped zinc sulphide quantum dots

Bilirubin (BR) is a protective antioxidant generated as end-product of heme catabolism in human. However, BR accumulation in biological tissues in connection with neonatal and hereditary jaundice causes severe hyperbilirubinemia and neurotoxicity. Herein, a fluorescence turn-off sensor for the detection of BR, a major biomarker for jaundice, is designed based on l-cysteine capped manganese doped zinc sulphide quantum dots (Mn:ZnS QDs). The QDs were synthesized by a microwave assisted chemical co-precipitation method. Under optimum conditions, the luminescence quenching response of Mn:ZnS QDs can be effectively used for detection of BR in the linear range of 10.99 μM - 63.84 μM BR. The limit of detection (LOD) is as low as 1.8 μM and limit of quantification (LOQ) is 6 μM. The plausible mechanism behind BR induced luminescence quenching is reductive photo-induced electron transfer (PET) in which Mn:ZnS QDs act as electron acceptor and BR act as electron donor. The developed sensor show good selectivity for BR over other co-existing biomolecules such as creatine, cholesterol, bisphenol, glutathione, uric acid, urea, hemoglobin, fructose, galactose and glucose. The developed sensor was validated by the detection of BR in spiked human serum and urine samples. For practical applications, a paper strip based sensor was also developed.

Facile Microwave-assisted Synthesis Manganese Doped Zinc Sulfide Nanoparticles

Undoped and manganese doped zinc sulfide nanoparticles were produced by a fast, one-step and two-component microwave-assisted synthesis method. The solid phase retains around 78% of the initial Mn concentration, as revealed by Particle Induced X-ray Emission analysis. X-ray diffraction patterns confirmed zinc blende structure and in the transmission electron microscopy images, nanoparticles with triangular prism and cube shapes were observed, respectively with an average particle size around 7 nm and 13 nm. Dried powders of zinc sulfide nanoparticles, doped with 0.1 mol% and 0.7 mol% of Mn ions, show highest brilliance of luminescence under UV light. Increasing dopant levels resulted in a diminishing emission that vanishes above 4% of dopant concentration. The synthesis of ZnS was monitored and two main events were detected, one at 145 °C corresponding to the sol-gel phase formation and another after ~3 min at 300 °C where the precipitation of the zinc sulfide nanoparticles occurs.

Sensing and photocatalytic activity of zinc sulfide quantum dots based on charge transfer process to analyte molecule

We demonstrated the efficientcharge transfer between manganese doped zinc sulfide quantum dots (QDs)and an analyte molecule, methaneor methylene blue dye, by means of photoluminescence properties of ZnS QDs. In the presenceof methane QDs arefound to exhibit non-uniform increasing of luminescence intensity due to specific charge transfer from analyte to QD defect states. It is revealed that charge transfer leads to destruction of methylene blue dye molecule which makes possible to use the QDs for organic dye removal in aqueous solution. The limit of methane detection is 100 ppm. The photocatalytic rate of methylene blue degradation is 0.033 s−1 which is almost two orders higher than Degussa P25 rate.

Manganese-Doped Zinc Sulfide Quantum Dots for Methane Detection in Aqueous Media

A simple aqueous based synthesis technique at room temperature was performed for preparation manganese-doped zinc sulfide quantum dots. Under 4 eV excitation quantum dots show photoluminescence bands at 2.11 and 3.1 eV corresponded to Mn2+and intrinsic ZnS emission respectively. ZnS quantum dots were used as the luminescent sensing element for methane detection in aqueous media. The luminescent sensor response occurs due to photoinduced electron transfer from QDs to methane molecule resulting in QD luminescence quenching.

Understanding the mechanoluminescent mechanisms of manganese doped zinc sulfide based on load effects

In this work, manganese doped zinc sulfide (ZnS: Mn2+) powder was synthesized, which was further composited with epoxy resin. In addition to the bright photoluminescence (PL), two types of mechanoluminescence (ML), i.e., friction and compression induced luminescence, were observed in ZnS: Mn2+/epoxy composites. To deeply understand the mechanoluminescent mechanisms of ZnS: Mn2+, the performance differences between PL and ML were investigated. The results suggested that the piezoelectric effect induced electroluminescence should not be the exact mechanism of ML. Moreover, load effects on the friction and compression induced ML as well as the thermoluminescence (ThL) were investigated. The variations of trap depth and carrier density in ZnS: Mn2+ before and after mechanics stimulation provided direct evidence that the release of electrons from traps should be responsible for ML. The load effects of ML also supported the proposed trap-based mechanisms, and the underlying theory was discussed in detail. This work first presents solid evidences for the trap-based mechanoluminescent mechanisms of ZnS: Mn2+ in elastic region.