ZnS Powders Research Articles

Development and characterization of novel Fe2+:ZnSexS1-x solid solution laser ceramics for mid-infrared laser application

In this study, Fe2+:ZnSexS1-x (0.6 ≤ x ≤ 1) solid solution laser ceramics with cubic crystal structures were prepared for the first time via hot pressing sintering, using FeSe, ZnSe, and ZnS powders. The resulting ceramics exhibit a unique combination of the optical and physical properties of Fe2+:ZnSe and Fe2+:ZnS. An increase in the ZnS content led to a blueshift in the maximum absorption spectra of Fe2+ ions and an enhancement in Vickers hardness. These findings suggest that Fe2+:ZnSexS1-x solid solution ceramics could serve as promising gain media for mid-infrared solid-state lasers, offering a novel approach for the development of directly pumped mid-infrared laser systems.

Ce-doped ZnO nanonails synthesized by a simple thermal evaporation method for photocatalytic degradation

One-dimensional (1D) nanomaterials have garnered significant scientific and technological attention due to their potential applications in electronics devices, gas sensing, energy conversion, and photocatalysis. However, the development of a simple and low-cost technique for 1D nanostructure synthesis remains a challenge. The doping of ZnO nanostructures has proven to be an effective way to improve their internal properties. In this work, one-dimensional ZnO and Ce-doped ZnO nanorods and nanonails were synthesized by a simple thermal evaporation method using different weight ratios of ZnS and CeO2 precursor powders in a catalyst-free process. The effects of cerium doping concentration on the structural, morphological, and optical properties of the as-prepared samples were investigated. XRD analysis confirmed that the crystal structure was converted from the cubic ZnS phase to the hexagonal ZnO phase with increasing annealing temperatures. The UV–Vis spectra showed that the optical absorption edge of Ce-doped ZnO samples was slightly red-shifted. Additionally, the band gap energy decreases with increasing cerium concentration. SEM images showed that the morphology of the structures obtained changed from nanorods to nanonails as the Ce content increased. The incorporation of Ce ions into the ZnO matrix has been successfully confirmed by HRTEM, Raman, and EDX analysis. Photocatalytic activity studies showed that Ce-doped ZnO samples exhibited significantly enhanced photocatalytic performance compared to pure ZnO for the degradation of rhodamine B under UV radiation. These results may suggest the use of heterogeneous photocatalysis as an efficient, cheap, and environment-friendly alternative for the removal of pollutants from water and the use of Ce-doped ZnO as a promising candidate.

Synthesis and alloying of zinc sulfide in a homogeneous system based on dodecane, its identification and optical properties

Zinc sulfide doped with Mn2+ ions was synthesized in a homogeneous dodecane medium by the method of emerging reagents. By methods of chemical and X-ray phase analysis, IR spectroscopy, electron microprobe microscopy, identification of products was carried out, photographs of the surface of powder particles (SEM) were recorded. Based on the totality of the results, a conclusion is made about the formation of nanoscale objects having a polytype structure with a predominance of distorted cubic crystals forming agglomerates up to 10 microns in size in ZnS powder and up to 100 microns in ZnS–Mn powder. The formation of nanoscale ZnS particles is confirmed by spectral data. The effect of manganese ions on the photoluminescence (FL) of the powder is manifested by a change in the type of the descending branch of the ZnS–Mn FL band, it is associated with recombination processes at the levels of defects formed by Mn2+ ions in the ZnS structure at their low concentration.

Alpha-ray imaging with alkali copper halide scintillator

Internal exposure for decommissioning workers at the Fukushima Daiichi Nuclear Power Plant must be prevented, and we have developed a monitoring system for alpha-ray emitting dust (alpha dust). When the dust size is less than several tens of micrometers, a dust protection maskdoes not work effectively to prevent internal exposure. Since no devices have been operated to observe alpha-dust images in real-time up to now, we have developed an alpha-ray imaging detector consisting of a scintillation material and imaging detector. Scintillators are required to have high light output and chemical stability. Cs3Cu2I5 (CCI) scintillator was found to be one of the candidates, and an imaging test was operated with this material. The CCI crystal was grown by the Bridgman-Stockberger method, and a scintillation sheet for alpha-ray imaging was prepared by CCI microcrystals with a thickness of approximately 70 μm on a 200-μm thickness transparent polyethylene terephthalate film as a first imaging test. The sheet was irradiated with 5.5-MeV alpha rays from an 241Am source, and scintillation photons were detected with a CMOS camera through an optical lens. We succeeded in visualizing alpha rays, and a position resolution of our system achieved approximately 16.2 ± 2.6 μm (10–90 %). This resolution was similar value to other imaging devices with Ag:ZnS powder scintillator, and a CCI single crystal sheet was expected to reach better resolution.

Spectroscopic and electrical analysis of p–Si/n-ZnSxSe1−x (0.0 ≤ x ≤ 1.0) heterostructures for photodetector applications

The present paper focuses on the properties of the p–Si/ ZnSxSe1−x (0 ≤ x ≤ 1) heterojunctions in photodetector applications. The heterostructures were fabricated by depositing ZnSSe on Si wafer using the thermal co-evaporation technique with ZnS and ZnSe powders. The GIXRD study showed that films were in cubic phase, and the prominent peak was shifted with composition x. The maximum crystallite size of the films was found for x = 0.8. The presence of point defects and emission related to higher Zn content in the thin films was confirmed by Photoluminescence. Temperature-dependent Raman analysis reveals that the longitudinal optical phonon modes shift to the lower wavenumber side as temperature decreases, which describes the variation of lattice parameters with temperature. The barrier height and ideality factor were calculated by implementing the thermionic emission. The photoresponse of p–Si/ ZnSxSe1−x heterostructures was studied. The investigation showed that the sample with x = 0.8 exhibits high photosensitivity and is suitable for photodetector applications.

Controllable Synthesis of Well-Monodispersed ZnS Nanospheres Through a Simple Sol–Gel Method and a Rapid Co-Phase Precipitation Method

In this study, the sol–gel method was used to prepare well-monodispersed ZnS nanopowders with a powder size of approximately 0.5 μm. The starting materials used were Zn(NO3)2 · 6H2O and C2H5NS. However, the agglomeration problem of the powders was addressed by adding an appropriate amount of (C6H9NO)n. The sol–gel method successfully produced submicron-sized ZnS powders. To further reduce the powder particle size, a rapid co-phase precipitation method was employed. This method involved using ZnCl2 and C2H5NS, which yielded ZnS nanopowders with a particle size of approximately 50 nm. The key focus of this method was on selecting the precipitating agent and emulsion to control the precipitation of ZnS nanoparticles. Both methods resulted in finer powder particle sizes and higher powder purity compared to commercial ZnS powders. These improvements in the optical and mechanical properties of ZnS IR-transmitting ceramics are significant. Overall, this study demonstrates the effectiveness of using these methods for synthesizing high-quality ZnS nanopowders.

Development of a capillary plate based fiber-structured ZnS(Ag) scintillator

Silver-doped zinc sulfide (ZnS(Ag)) is an opaque powder scintillator that is mainly used for detection or imaging of charged particles such as alpha particles. Since ZnS(Ag) is not transparent, the thickness of ZnS(Ag) was limited to ∼10 μm. If a thicker ZnS(Ag) scintillator could be developed, it would be useful for studies such as high-energy particle ion detection as well as beta particle or gamma photon detection. We developed a ZnS(Ag) fiber-structured scintillator using a capillary plate in which ZnS(Ag) powder was encapsulated in the capillaries. The thickness of the capillary plate was 400 μm, and the light produced in ZnS(Ag) escaped from the capillaries, spread through the transparent lead glass area, and reached the opposite side of the plate; consequently, the opaque character and absorption of light could be avoided. The amount of light emitted from the capillary plate based fiber-structured ZnS(Ag) was almost the same as that of a commercially available ZnS (Ag) film, but the detection efficiency was about 1/5 (∼ 20%). The amount of light emitted from beta particles and gamma photons per MeV was less than 1% of that from alpha particles. The spatial resolution of the developed capillary plate based fiber-structured ZnS(Ag) scintillator for 5.5 MeV alpha particles was ∼200 μm FWHM. Imaging of the slits and light spots from alpha particles could be achieved with the developed scintillator combined with an electron-multiplied charge-coupled device (EM-CCD) camera. The developed capillary plate based fiber-structured ZnS(Ag) will be useful for detecting high-energy particle ions.

Gas-Sensing Properties and Preparation of Waste Mask Fibers/ZnS Composites.

To realize the resource utilization of waste mask fibers (MF), a layer of ZnS nanoparticles was grown on MF by a one-step hydrothermal method, and a MF/ZnS sensor was successfully prepared. This is the first time that resource utilization of MF has been combined with the development of a high-performance gas sensor. The MF/ZnS sensor showed high sensitivity and recoverability to target vapors at room temperature. Compared with ZnS powder loaded on a ceramic substrate, the MF/ZnS composite responses to four analytes have been improved by 8.4~35.2 times. In addition, the time for the MF/ZnS sensor to complete one response–recovery cycle for all four analytes was less than 30 s. This should be attributed to the high gas permeability of the MF substrate, which made the ZnS particles loaded on the MF more fully exposed to contact with the target vapors. This work not only provides a simple and low-cost method to optimize the sensing performance of gas sensors but also provides a new way for the resource utilization of MF.Graphic Supplementary InformationThe online version contains supplementary material available at 10.1007/s11664-022-09644-1.

An Al-12Si/ZnS powder inoculant for eutectic silicon in Al-12Si alloy

To obtain high-performance Al-Si-based cast alloys, refinement and modification of Si phases are required. An Al-12Si/ZnS powder inoculant was designed and fabricated using a chemical bath deposition method. The efficiency of the inoculant for modifying the eutectic Si phase in as-cast Al-12Si alloy was studied. Results show that Al-12Si/ZnS powder can significantly refine the eutectic Si in Al-Si cast alloys. The best refinement effect for eutectic Si is achieved with 17.5wt.% Al-12Si/ZnS powder. Coarse long needle-shaped eutectic Si with a length of 18 µm was modified into approximately spherical shape with a diameter of 6.53 µm, which is evenly distributed throughout the alloy. The E2EM model calculation indicates that the inter-plane misfit (Fp) and inter-atomic spacing misfit (Fr) between ZnS and Si are all less than 0.5%, which confirms that ZnS is a potential nucleation site for Si phase. The hardness, tensile strength, and elongation of Al-12Si alloys modified with 17.5% Al-12Si/ZnS powder increase 6.30%, 16.18% and 55.45%, respectively, compared to the unmodified Al-12Si alloy. The fracture behavior of the alloy with 17.5wt.% Al-12Si/ZnS powder is dominated by transgranular fracture supplemented by intergranular fracture.

Synthesis, structural and optical properties of ZnS/ZnO heterostructure-alloy hexagonal micropyramids

Heterostructure alloys with controlled structure and composition are essential for future electronics and optoelectronics. While heterostructure formation creates sharp electronic junction, alloying allows bandgap tunability. Herein, ZnS/ZnO heterostructure-alloy hexagonal micropyramids are grown on Si/SiO2 wafers for the first time by facile thermal evaporation of ZnS powder. It is found that the pyramids with a based size of few micrometers are grown along different crystallographic directions and neighbored by ZnS microrods. XRD and XPS spectra showed that ZnS, ZnO, and ZnSO wurtzite phases coexist in the as-received samples. FESEM images, in situ point, and EDS elemental mapping spectra reveal that the micropyramids are composed of Zn, S, O, but each element's ratio changes with substrate temperature and is different at different faces of a single micropyramid. Using a high-spatial CL-FESEM, the profile of CL spectra along the substrate and at different faces in a single micropyramid were in-situ measured and disclosed red-shifted of ZnS band-edge emission with increasing substrate temperature, and the formation of new emission bands in the range from ∼345 to 352 nm. This new emission band is attributed to the formation of the ZnSO alloy phase. Our results demonstrated that the optical properties of the obtained ZnS/ZnO heterostructure-alloy hexagonal micropyramids could be tunned by controlling the substrate temperature and indicates potential applications of the ZnS/ZnO heterostructure alloy in optoelectronic and photonic applications.

Selenium ligands doped ZnS for highly efficient immobilization of elemental mercury from coal combustion flue gas

At the upstream of electrostatic precipitator (ESP) or bag house (BH), using sorbents with excellent adsorption capacity is a common method for capturing mercury (Hg) from coal-fired power plant flue gas. ZnS, an inexpensively and conveniently prepared metal sulfide, can even be collected from nature, and is a promising candidate for its sulfur resistance. In this work, selenium ligands (Se 2− and Se 0 ) were introduced into ZnS for enhancing Hg 0 capture capability. The experimental results showed that the Hg 0 removal efficiency can reach 100% in a wide temperature range from 40 ℃ to 300 ℃ when the Se ratio was 30 wt% (30SZ). Compared with pure ZnS and Se powder, Se/ZnS were all exhibited an excellent absorbent capability. A long term experiment was imposed on 30SZ, and the sample adsorption capacity remained unchanged. Moreover, O 2 and SO 2 had insignificant effects on Hg 0 adsorption, NO showed a slight competition for Hg 0 adsorption. It was found that Se ligands (Se 2− and Se 0 ) and surface active S (S 2- and S) sites immobilized Hg 0 over the Se/ZnS surface, and in turn the adsorbed Hg 0 was basically converted to HgSe and HgS, and the adsorption mechanism was also proposed. With these advantageous performances, 30SZ is expected to be an economically feasible and scientifically sound sorbent. This work also provides a promising way for Hg 0 capture from coal combustion flue gas. • Inactive synthesized ZnS were functionalized to be highly efficient mercury sorbents. • The removal efficiencies can reach 100% in a wide temperature range from 40 to 300 ℃. • Se/ZnS had higher binding energy of Hg-Se to improve the adsorption capability. • The captured mercury is mainly converted into HgSe by chemisorption. • The components in the SFG have no obvious poison effects to synthesized 30SZ.

Effect of ZnS/C Mass Ratio on the Morphologies and Luminescence Properties of ZnO Nano/Microstructures Synthesized via Thermal Evaporation of ZnS and C Powder Mixtures

ZnO nano/microstructures were grown via a simple thermal evaporation process in air at atmospheric pressure. Mixtures of ZnS and carbon powders were used as the sources. The effects of growth temperature and mass ratio of carbon powder to ZnS on the morphologies and luminescence properties of the ZnO nano/microstructures were investigated in this study. When the growth temperature was 1000 <sup>o</sup>C, ZnO nanowires with a hexagonal wurtzite crystal structure started to be formed and were preferentially grown along the [0001] direction. As the temperature increased to 1200 <sup>o</sup>C, the crystal growth in the lateral direction perpendicular to the [0001] direction was enhanced, which resulted in a decreasing aspect ratio of the onedimensional ZnO nanowires. When source powders with different mass ratios of ZnS:C=2:1, 1:1 and 1:2 were used to grow ZnO nano/microstructures at 1200 <sup>o</sup>C, ZnO microrods with wurtzite crystal structure were formed in all the samples. As the mass ratio of carbon powder to ZnS increased, the aspect ratio of ZnO microrods was reduced, which suggests that the carbon powder enhanced the growth of ZnO microrods in the lateral directions. A strong ultraviolet emission band centered at 380 nm was observed in the ZnO nano/microstructures synthesized using the source powders with the mass ratios of ZnS:C=1:1 and 1:2, indicating that the ZnO nano/microstructures had a high crystalline quality.

Mechanochemical Ignition of Self-propagating Reactions in Zn-S Powder Mixtures

The present work examines the mechanochemical reactivity of Zn-S powder mixtures subjected to mechanical processing by ball milling. Chemical composition, collision energy, powder charge inside the reactor, number of milling balls, Zn microstructure and temperature have been systematically varied to gain detailed information on the physical and chemical responses of reactant powders. It is shown that the mechanical activation of mixtures with intermediate Zn contents determines the ignition of self-sustaining high-temperature reactions that lead to the α and β ZnS line compounds and residual unreacted elements. Within the intermediate compositional range, ignition time decreases as the impact energy, the number of milling balls and the temperature increase and as the mass of powder decreases. In contrast, ignition times decrease as the hardness of Zn powder increases. Experimental findings are interpreted with the help of a phenomenological kinetic model.

Cu-doped ZnS coatings for optoelectronics with enhanced protection for UV radiations

Molecular dopants are of great importance in nano-chemical compounds by improving the function of inorganic electronic devices. In this article, Cu:ZnS (CZS) powders were made using the chemical method. Thin films were deposited by the physical method. The CZS films showed cubic crystal structures with a single hexagonal peak. The impact of an increase in Cu2+ dopants was investigated not only in reducing the grain size but also in reducing the optical energy gap and deviation parameters of the lattice constants. The estimated energy gaps of CZS nanostructures (NSs) were (3.70, 3.66, 3.0, and 3.76 eV) for Cu dopant (0, 1.5, 3.0, and 4.5 at.%); an indication of a blueshift. Redshift was also noticed for Cu dopant 4.5% due to interstitial sites. Moreover, the transmittance for all specimens was (70–95%) in the visible and near IR-region and reduced in the UV range (< 400 nm). The decrease in light transmittance occurred in the UV range when the Cu2+ concentration increased. Besides, the study revealed a reduction in the power loss of the thin film indicating high quality and a highly optimized electrical and electronic system. The Neural Network was utilized to obtain validation of results by the theoretical study.

Synthesis of Mn-Doped ZnS Nanoparticles and Its Characterization

ZnS powders doped with manganese (ZnS:Mn) was synthesized by the sol gel method. The structural and optical characteristics are studied using various techniques. Analysis with X-ray diffraction shows that cubic ZnS phase is formed with average crystallite sizes varying between 10 nm and 13 nm. There is no phase transformation due to Mn2+ doping. The formation of ZnS was confirmed by X-ray photoelectron spectroscopy (XPS) measurement. TEM images indicated the spherical shape of the nanoparticles. However, optical study has shown a strong reflectance in the visible range. The band gap (Eg) of ZnS:Mn is varied between 3.51 eV and 3.56 eV. The photoluminescence properties of ZnS:Mn nanopowders were studied.

Brightness enhancement of a direct-current-driven electroluminescent device prepared with zinc-sulfide powder

In this paper, we report an improved luminous efficiency of a direct-current-driven electroluminescent (EL) device using ZnS powder by controlling electron and hole injection barriers. The emission layer was fabricated by screen-printing of an EL paste using Cu-coated ZnS particles on a transparent conductive indium–tin-oxide electrode. The device was completed by stacking an Al thin film on the emission layer by thermal evaporation. We applied various forming voltages to investigate the current–voltage–luminescence characteristics of the device. An abrupt change in current during the forming process was caused by variation of the electron-blocking barrier toward the anode. The hole-injection barrier from the anode to the emission layer increased with the forming voltage. The obtained results indicated that the hole-injection barrier to the emission layer can be lowered by inserting materials with a low highest-occupied-molecular-orbital (HOMO) energy level between the anode and emission layer. We achieved a brightness enhancement of 29% by employing a thin film of poly-N-vinyl carbazole with a HOMO level of −5.6 eV as a hole-injection layer on the anode. We believe that the presented results will guide further studies for efficiency improvement of EL devices using powder particles applicable to next-generation lighting and displays.

ZnS nanoparticles as the electrode materials for high-performance supercapacitors

ZnS nanoparticles electrode has been synthesized via a simple hydrothermal technique and anion exchange reaction for supercapacitor application. The as-prepared ZnS powder possesses high crystallinity and phase purity, which possesses uniform nanoparticles with an average grain size of 30–40 nm and homogeneous dispersion. The shape of cyclic voltammetry curves with different scanning rates indicates a reduced polarization effect of the ZnS nanoparticles electrode. The ZnS electrode manifests drastically superior electrochemical performance covering a supreme reversible specific capacitance of 824 F g−1 at 1 A g−1, outstanding rate capability of 57.7% capacitance retention even if the current density increases by 20 times, and prominent ultralong-life at large current densities of 5.0 and 10.0 A g−1. The initial specific capacitance of ZnS nanoparticle is 557 F g−1 at 10 A g−1, and it also delivers 518.4 F g−1 after 10,000 cycles with a high capacitance retention of 93.1%. These above results shed light on new avenues for promising electrode materials in supercapacitors.

ZnO/ZnS core-shell nanostructures for hydrogen gas sensing performances

Abstract ZnO/ZnS core-shell structures were hydrothermally grown on SiO2 substrates functioning as hydrogen gas sensing chips. Results indicate that a core-shell structure with an appropriate sulfurization period of 10 min had better H2 sensing performance than those of all other growth conditions. Furthermore, multiple material characterizations revealed that ZnS with a growth time of 10 min could form high-quality and good-adherent ZnS powders with moderate thickness attached to the ZnO nanorods. Because of their small size, portability, simple fabrication and high sensitivity, ZnO/ZnS core-shell based H2 gas sensors show promise for future H2 detecting applications.

New insights in structural characterization of transparent ZnS ceramics hot-pressed from nanocrystalline powders synthesized by combustion method

Zinc sulfide transparent ceramics have been fabricated by hot pressing (HP) powders prepared by a newly developed combustion method. Chemical, structural and microstructural properties of powders and ceramics were characterized using different experimental techniques (XRD, SEM-EDS, laser granulometry, TEM, BET, FT-IR spectroscopy). ZnS powders were densified to full density by HP under vacuum atmosphere. The ceramics exhibit highly dense microstructure with mean grain size of 1 μm. TEM characterization identified, both in powders and ceramics, twins and simple stacking faults due to the aperiodic distribution of hexagonal domains. With optical transmission of the theoretical level (∼75%), without absorption band (at 6 μm) and with negligible optical loss, in the 4–12 μm region, the ceramics exhibit better optical performances than standard grade CVD ZnS, and unprecedented performances for hot-pressed ZnS.

Luminescence of undoped commercial ZnS crystals: A critical review and new evidence on the role of impurities using photoluminescence and electrical transient spectroscopy

Bulk undoped ZnS materials exhibit relatively bright yet diverse luminescence behavior, which has, in recent years, been attributed to intrinsic defects. However, the luminescence also resembles that of doped materials, implying a role of impurities. Luminescence features have also been attributed to oxygen impurities causing defect clusters or energy band anti-crossing. Thus, this study couples optical and electrical techniques, such as band edge transmission, photoluminescence (PL), PL excitation, radioluminescence, thermoluminescence, optical deep level transient spectroscopy, and photoinduced current transient spectroscopy, to explore the identity of defect levels. ZnS materials studied are commercial single crystals made by physical vapor transport, high-pressure Bridgman, and powder processing. These undoped bulk ZnS exhibit luminescence behavior similar to that of reported doped ZnS powders (10−4 to 10−2 mol. % doping for luminescent materials). Dopants (such as Al, Cl, Cu, and Ag) are also commonly found impurities in ZnS; hence, it is reasonable to believe they have a role in the luminescence of nominally undoped ZnS. By comparing the variation in optical and electrical properties between samples to the processing method and the rich literature on intentionally doped ZnS, this study shows a possible dominant contribution of impurities and impurity-containing defects on the luminescence of bulk “undoped” ZnS. Hence, there is no need to resort to complex mechanisms to explain the luminescence, but rather the metal and halide impurities and their defect complexes determine the main characteristics of luminescence in this wide-bandgap semiconductor.