Luminescence Properties Of ZnS Research Articles

Study on the Luminescence Properties of ZnS:Mn2+ Particles by High Temperature Solid Phase Method

ZnS has attracted wide attention for its potential applications in optoelectronic fields, such as solid-state lighting, fluorescent probes, electroluminescent devices and field emission displays. In this work, Mn2+-doped ZnS with hexagonal structure were prepared by high temperature solid phase method using MnCO3 as manganese source, and the effect of Mn2+ doping on ZnS was studied. The results show that the particle shape of ZnS doped with Mn2+ is hexagonal structure, Mn2+ doping changes the position and intensity of ZnS absorption spectrum and photoluminescence band. The absorption peak at 340 nm progressively moves to the right as Mn2+ doping rises, a new conspicuous absorption peak forms in the visible area, and the maximum photoluminescence intensity of ZnS:Mn2+ steadily increases. However, when the Mn2+ doping exceeds the ratio of 4 at.%, the photoluminescence intensity showed a decreasing trend. This indicates that the number of effective emission centers reaches the maximum when the doping concentration of Mn2+ is the most suitable.

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.

Effect of the doping method on luminescent properties of ZnS:Ag

Effect of the doping method on luminescent properties of ZnS:Ag

Combinatorial Tuning of Structural and Optoelectronic Properties in CuxZn1−xS

Summary P-type transparent conductors (TCs) are important enabling materials for optoelectronics and photovoltaics, but their performance still lags behind n-type counterparts. Recently, semiconductor CuxZn1−xS has demonstrated potential as a p-type TC, but it remains unclear how properties vary with composition. Here, we investigate CuxZn1−xS across the entire alloy space (0 ≤ x ≤ 1) using combinatorial sputtering and high-throughput characterization. First, we find a metastable wurtzite alloy at an intermediate composition between cubic endpoint compounds, contrasting with solid solutions or cubic composites (ZnS:CuyS) from the literature. Second, structural transformations correlate with shifts in hole conductivity and absorption; specifically, conductivity increases at the wurtzite phase transformation (x ≈ 0.19). Third, conductivity and optical transparency are optimized within a "TC regime" of 0.10

The influence of Mn content on the structure and photoluminescence of ZnS:Mn nanostructure

ZnS:Mn nanostructure was grown on Si substrates by hydrothermal method. The effects of Mn doping concentration on the structure and luminescence properties of ZnS:Mn were studied in detail. XRD patterns show that all the samples have a strong diffraction peak at about 28.5°, which belongs to β-ZnS (111) orientation. As the concentration of Mn increases, the diffraction peak shifts to a small angle, and the average grain size decreased. SEM images show that ZnS:Mn nanostructure is spherical particle, and these particles are closely bonded to the substrate. PL spectra of all samples are composed of two luminescence bands: green light around 500nm and orange-yellow light around 580nm. When the doping concentration of Mn increased from 0.5% to 2%, the 4T1-6A1 emission of Mn2+ around 580nm gradually increased, and when the concentration exceeded 2%, the luminous intensity decreased instead.

Photoluminescence properties of ZnS:Mn single crystal effected by defect drift in electric and pulsed magnetic fields

Luminescence properties of ZnS:Mn single crystal are studied before and after drift of defects in electric field additionally influenced by pulsed magnetic field. It is detected that besides the change of luminescence center quantity the efficiency of channels of radiative and non-radiative recombination at the anode and cathode areas changes also due to the change of the Fermi energy position in these areas of the crystal. Simultaneous presence of two types of manganese ions in ZnS:Mn crystal possessing different local symmetry is found. These ions are sensitizers for different by nature emitting centers for self-activation (SA) and Mn-related photoluminescence. Selectivity in transfer of excitation to a particular emission center (SA or Mn) is defined by the efficiency of resonance excitation transfer.

Luminescent properties of ZnS<sub>x</sub>Se<sub>(1-x)</sub> mixed crystals obtained by solid-phase synthesis and melt-growing

Luminescent properties of ZnS<sub>x</sub>Se<sub>(1-x)</sub> mixed crystals obtained by solid-phase synthesis and melt-growing

Effect of structure, size and copper doping on the luminescence properties of ZnS

Luminescence properties of wurtzite and cubic forms of bulk ZnS have been investigated in detail and compared with that of ZnS nanoparticles. Blue emission observed in both hexagonal and cubic forms of undoped bulk ZnS is explained based on electron–hole recombination involving electron in conduction band and hole trapped in Zn2+ vacancies where as green emission arises due to electron hole recombination from Zn2+ and S2− vacancies. Conversion of wurtzite form to cubic form is associated with relative increase in intensity of green emission due to increased defect concentration brought about by high temperature heat treatment. Copper doping in ZnS, initially leads to formation of both CuZn and Cui (interstitial copper) centers, and latter to mainly CuZn centers as revealed by variation in relative intensities of blue and green emission from the samples.

Microbe‐Assisted Synthesis and Luminescence Properties of Monodispersed Tb3+‐Doped ZnS Nanocrystals

Tb3+‐doped zinc sulfide (ZnS:Tb3+) nanocrystals were synthesized by spray precipitation with sulfate‐reducing bacterial (SRB) culture at room temperature. The morphology of the SRB and ZnS:Tb3+ nanocrystals was examined by scanning electron microscopy, and the ZnS:Tb3+ nanocrystals were characterized by X‐ray diffractometry and photoluminescence (PL) spectroscopy. The PL mechanism of ZnS:Tb3+ nanocrystals was further analyzed, and the effects of Tb3+ ion concentration on the luminescence properties of ZnS:Tb3+ nanocrystals were studied. ZnS:Tb3+ nanocrystals showed a sphalerite phase, and the prepared ZnS:Tb3+ nanocrystals had high luminescence intensity under excitation at 369 nm. The main peak position of the absorption spectra positively blueshifted with increasing concentrations of Tb3+ dopant. Based on the strength of the peak of the excitation and emission spectra, we inferred that the optimum concentration of the Tb3+ dopant is 5 mol%. Four main emission peaks were obtained under excitation at 369 nm:489 nm (5D4→7F6), 545 nm (5D4→7F5), 594 nm (5D4→7F4), and 625 nm (5D4→7F3). Our findings suggest that nanocrystals have potential applications in photoelectronic devices and biomarkers.

Luminescence properties of ZnS:Cu, Eu semiconductor nanocrystals synthesized by a hydrothermal process

ZnS:Cu, Eu nanocrystals with an average diameter of ∼ 80 nm are synthesized using a hydrothermal approach at 200 °C. The photoluminescence (PL) properties of the ZnS:Cu, Eu nanocrystals before and after annealing, as well as the doping form of Eu, are studied. The as-synthesized samples are characterized by X-ray diffraction, scanning electron microscopy, inductively coupled plasma-atomic emission spectrometry, and the excitation and emission spectra (PL). The results show that both Cu and Eu are indeed incorporated into the ZnS matrix. Compared with the PL spectrum of the Cu mono-doped sample, the PL emission intensity of the Cu and Eu-codoped sample increases and a peak appears at 516 nm, indicating that Eu3+ ions, which act as an impurity compensator and activator, are incorporated into the ZnS matrix, forming a donor level. Compared with the unannealed sample, the annealed one has an increased PL emission intensity and the peak position has a blue shift of 56 nm from 516 nm to 460 nm, which means that Eu3+ ions reduce to Eu2+ ions, thereby leading to the appearance of Eu2+ characteristic emission and generating effective host-to-Eu2+ energy transfer. The results indicate the potential applications of ZnS:Cu, Eu nanoparticles in optoelectronic devices.

Effect of inorganic shells on luminescence properties of ZnS:Ag nanoparticles

The hydrothermally synthesized Ag-doped ZnS (ZnS:Ag) nanoparticles have been coated with inorganic shells by a chemical precipitation method. The ZnS:Ag/ZnS, ZnS:Ag/CdS, and ZnS:Ag/ZnO core–shell nanoparticles with different thickness of ZnS, CdS, and ZnO shells have been prepared. The effects of shells on the luminescence properties of ZnS:Ag cores have been investigated through the photoluminescence (PL) spectra and luminescence stabilities of products. In the core–shell nanoparticles involved here, the ZnO shell can most significantly enhance the luminescence of ZnS:Ag cores. The 450 nm emission intensity of ZnS:Ag/ZnO nanoparticles is up to 125 % of that of ZnS:Ag nanoparticles. However, the ZnO shell can hardly influence the luminescence stability under ultraviolet irradiation. The ZnS shell can only increase the luminescence of ZnS:Ag cores to some extent, but it can improve the luminescence stability under ultraviolet irradiation. Although the CdS shell can improve the luminescence stability to some extent, it quenches the luminescence of ZnS:Ag nanoparticles dramatically.

与掺杂浓度相关的ZnS∶Mn纳米粒子的发光性质

Mn-doped ZnS nanoparticles were prepared by the Sol-Gel process in this paper,and the influence of doping ion concentration on crystal structures and luminescent properties of ZnS:Mn nanoparticles was discussed.The structures of the samples were characterized by an X-ray diffractometer(XRD).The results show that the as-prepared ZnS:Mn nanoparticles belong to the cubic sphalerite structure.The parvafacies do not occur when Mn2+-doping concentration reaches 6% and the average particle sizes of nanoparticles decrease with the increase of doping concentration.Photoluminescence(PL) spectroscopy and fluorescence spectrum results show that the emission wavelengths of ZnS:Mn nanoparticles around 590 nm can be adjusted by changing the concentration of the ions.In addition,the influence of temperature on morphology and luminescent properties of nanoparticles was studied.The result observed from a high resolution transmission electron microscopy(HRTEM) shows that the average particle sizes of ZnS∶Mn samples increase to about 20 nm after ageing for 1 h at the temperature of 50 ℃.The heating ageing is beneficial to Mn2+ fluorescence produced at 590 nm for ZnS∶Mn nanoparticles.

Synthesis and luminescence properties of ZnS and metal (Mn, Cu)-doped-ZnS ceramic powder

ZnS and metal (Mn, Cu)-doped-ZnS were successfully prepared by wet chemical synthetic route. The understanding of substituted metal ions (Mn, Cu) into ZnS leads to transfer the luminescent centre by small amount of metal dopant (Mn, Cu). Fourier transform infrared and X-ray diffraction were used to determine chemical bonding and crystal structure, respectively. It showed that small amount of metal (Mn, Cu) can be completely substituted into ZnS lattice. X-ray fluorescence was used to confirm the existence of metal-doped ZnS. Scanning electron microscope revealed that their particles exhibits blocky particle with irregular sharp. Laser confocal microscope and photoluminescence spectroscopy showed that ZnS and metal-doped-ZnS exhibited intense, stable, and tunable emission covering the blue to red end of the visible spectrum. ZnS, Mn-doped-ZnS and Cu-doped-ZnS generated blue, yellow and green color, respectively.

Luminescence Properties of ZnS:Cu,Tm Semiconductor Nanocrystals Synthesize by a Hydrothermal Process

ZnS:Cu,Tm nanocrystal with 15nm cubic structures have been synthesized by hydrothermal approach at 200°C. The photoluminescence (PL) properties and the effect of hydrothermal treatment time on the structure, morphology and PL spectra of ZnS:Cu,Tm samples have been studied. The as-obtained samples have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and FT-IR spectra.The result indicated that the PL emission spectrum of codoped with Cu and Tm sample compares with undoped ZnS and doped with Cu alone samples has a significant changes, while the PL emission peak has red shift and PL emission intensity increased. The samples size and crystallization are increase with extending of the treatment time. However, when the hydrothermal treatment time is too long(>12h), the PL emission intensity of sample instead of decreased. Demonstrated changes in surface state of nanomaterials have a greater impact on its luminescence properties.

A study of the surface and luminescence properties of ZnS : Mn2+ nanosized phosphors

The influence of the stabilizer and thermal treatment on the luminescence and surface properties of ZnS: Mn2+ nanosized phosphors has been studied. It has been found that ammonium polyacrylate is the optimal stabilizer for the use in the preparation of phosphors with nanoparticles that exhibits the highest brightness without applying thermal treatment. Analysis of the correlation between the luminescence spectral bands and the content of active surface adsorption sites has demonstrated that the model of active sites previously developed for the surface of zinc sulfide phosphors with large particles can also be used for nanosized phosphors.

SYNTHESIS AND PHOTOLUMINESCENCE OF WATER-SOLUBLE ZnS:Mn2+/ZnS QUANTUM DOTS BY NUCLEATION DOPING STRATEGY

We report the synthesis of luminescent-doped core/shell quantum dots (QDs) of water-soluble manganese-doped zinc sulfide (ZnS:Mn2+/ZnS) . QDs of ZnS:Mn2+/ZnS were prepared by nucleation doping strategy, with thioglycolic acid (TGA) as stabilizer in aqueous solution. Structure and optical properties of the ZnS:Mn2+/ZnS core/shell quantum dots were characterized by X-ray diffraction and photoluminescence emission spectroscopy. The influence of the synthesis conditions on the luminescent properties of ZnS:Mn2+/ZnS QDs is discussed. Different Mn2+ concentrations, ratios of the TGA/ (Zn+Mn) and thickness of the ZnS shell were used. Results showed that the ZnS:Mn2+/ZnS QDs are water-soluble and have improved fluorescence properties. Therefore, Mn2+ -doped ZnS quantum dots could be potential candidates as fluorescent labeling agents in biology.

Effects of the Template Composition and Coating on the Photoluminescence Properties of ZnS:Mn Nanoparticles

Mn-doped ZnS nanocrystals based on low dopant concentrations (0–2%) and coated with a shell of Zn(OH)2 have been prepared via soft template and precipitation reaction. The results indicate that the ZnS:Mn nanocrystal is cubic zinc blende structure and its diameter is 3.02 nm as demonstrated by XRD. Measured by TEM, the morphology of nanocrystals is a spherical shape, and their particle size (3–5 nm) is similar to that of XRD results. Photoluminescence spectra under ultraviolet region shows that the volume ratio of alcohol to water in the template has a great effect on the luminescence properties of ZnS:Mn particles. Compared with unpassivated ZnS:Mn nanocrystals, ZnS:Mn/Zn(OH)2 core/shell nanocrystal exhibits much improved luminescence and higher absolute quantum efficiency. Meanwhile, we simply explore the formation mechanism of ZnS:Mn nanocrystals in alcohol and water system and analyze the reason why alcohol and water cluster structures can affect the luminescent properties of nanoparticle.

XAFS analysis and luminescent properties of ZnS:Mn2+ nanoparticles and nanorods with cubic and hexagonal structure

Abstract ZnS:Mn 2+ nanocrystals (NCs) were synthesized by a simple solvothermal method at 180 °C in different solvents. The NCs prepared in ethanol yielded cubic nanoparticles (NPs) with diameters of 10–15 nm. The NCs prepared in ethylenediamine and water (1:1 in volume ratio) yielded hexagonal nanorods (NRs) with diameters of 8–10 nm. X-ray absorption fine structure (XAFS) measurements were carried out to probe the local environment surrounding the Mn ions in the NPs and the NRs. The results showed that Mn ions were incorporated into the ZnS lattice substituting the Zn sites. The yellow–orange emission from the Mn 2+ 4 T 1 – 6 A 1 transition was observed, its intensity relative to the blue–green emission increased from NPs to NRs. The surface effect was the main factor affecting the thermal and optical stability of NCs. The fluorescence lifetime of the Mn 2+ emission for the NPs and NRs was 0.662 and 0.224 ms, respectively.

Synthesis and luminescence properties of ZnS:Mn/ZnS core/shell nanorod structures

Mn-doped ZnS nanorods synthesized by solvothermal method were successfully coated with ZnS shells of various thicknesses. The powder X-ray diffraction (XRD) measurements showed the ZnS:Mn nanorods were wurtzite structure with preferential orientation along c-axis. Transmission electron microscopy images (TEM) revealed that the ZnS shells formed from small particles, growing along a-axis orientation, which was proved by the XRD measurements. Room temperature photoluminescence (PL) spectra showed that the intensity of Mn emission first increased and then decreased with the thickening of the ZnS shells. The effects of ZnS shells on the luminescence properties of ZnS:Mn nanorods is discussed.

Shell thickness dependence of luminescence intensity in core/shell ZnS:Mn/ZnS nanoparticles

In the present work, ZnS-coated ZnS:Mn nanoparticles were synthesized and the ZnS shell thickness dependence of Mn emission intensity was investigated. X-ray diffraction (XRD) measurements showed that both the ZnS:Mn nanoparticles and the ZnS shells possessed a zinc blende structure. Transmission electron microscopy (TEM) images and the quantum confinement effect shown in room temperature photoluminescence excitation (PLE) spectra gave the direct evidence that ZnS shells have been successfully coated on the ZnS:Mn nanoparticles. The room temperature photoluminescence (PL) spectra revealed an increase in the Mn emission intensity followed by a steady decline as the ZnS shells thickened. The effect of ZnS shells on the luminescence properties of ZnS:Mn nanoparticles is discussed.