Optical Properties Of Zn1 Research Articles

Studying the structural and optical properties of Zn1−xMgxO nanoparticles

Studying the structural and optical properties of Zn1−xMgxO nanoparticles

Preferential Crystallographic Orientation and Optical Properties in (Ag,Zn)‐Based Oxide Nanoparticle Thin Film Depending on Spark Voltage

The effect of spark voltage on nanoparticle (NP) formation, crystal structure, and optical properties of Zn and Ag‐containing metal oxides produced using the spark‐discharge (SD) technique was investigated. Quasispherical‐shaped nanocrystals were observed in ZnO, Ag:ZnO, and AgO NP samples prepared at different spark voltages. The NP sizes in ZnO and Ag:ZnO samples were close and decreased as the spark voltage increased. It was observed that when AgO was prepared with only low‐spark voltage (4.3 kV), tetrahedron/octahedron‐shaped NPs were also formed. 4.3 kV spark voltage increased the crystal growth rate in the (100)‐plane and 7 kV spark voltage also increased the crystal growth in the (002)‐plane in hexagonal wurtzite ZnO and Ag:ZnO samples. Therefore, the a‐axial preferred orientation of these samples at low‐spark voltage had switched to the c‐axial preferred orientation at high‐spark voltage. For AgO, the increase in spark voltage revealed the monoclinic structure more strongly. The film thicknesses of AgO samples were close to each other with both spark voltages. Although, it was determined that the AgO prepared with 7 kV was optically more transparent and its optical band gap was significantly widened. This case may be due to the more presence of dodecahedral‐shaped particles in the morphology of the AgO sample prepared. Therefore, the wider optical band gap of metal oxides decorated with such nanoparticles could indicate facet dependency. In addition, the film thickness and optical band gap of both ZnO and Ag:ZnO samples increased significantly depending on the increase of spark voltage. The optical band gap narrowed (redshifted) due to the effect of Ag ions entering the ZnO structure. As the spark voltage increased, the difference between the optical band gaps of ZnO and Ag:ZnO also increased. With the spark‐voltage effect, the change in preferential crystallographic orientations of ZnO and Ag:ZnO samples and the change in optical band gap depending on the NP shape of the AgO sample can offer significant advantages in terms of optoelectronics.

Electrospun Nanofiber Mats with Embedded Zinc Oxysulfide for Photoreduction of Nitrobenzene to Aniline under Mild Condition.

In this work, electrospun nanofiber embedded with zinc oxysulfide (Zn(O,S)) has been demonstrated as an efficient and robust photocatalyst for hydrogenation of nitrobenzene to aniline under solar light irradiation at mild conditions with methanol as the hole scavenger. The solid solution state of Zn(O,S) in electrospun nanofiber was successfully revealed by high-resolution transmission electron microscopy and X-ray diffraction analyses in which the lattice fringes and diffraction planes located in between those of ZnO and ZnS phases. Moreover, the electrochemical and optical properties of Zn(O,S) embedded in polyethylene oxide (PEO) nanofiber are found to be better than those of ZnO and ZnS indicating more efficient photocatalytic activities as well. The photocatalytic hydrogenation of nitrobenzene to aniline occurred completely within 2 h of the photocatalytic reaction with a reusability of 95% after five consecutive runs. Finally, the mechanism of photocatalytic hydrogenation by Zn(O,S) embedded in the PEO (PZOS) nanofiber involves a total of six electrons (e-) and six protons (H+) to hydrogenate nitrobenzene to nitrosobenzene, phenylhydroxylamine, and aniline.

Optical properties of Zn0.75Mg0.25O:Mn ceramics

Mn-doped ZnO, MgO and Zn0.75Mg0.25O samples ([Mn] = 0.1 at.%) were produced by conventional solid-state technique and investigated by means of XRD, EPR, absorption, photocurrent, photo- and cathodoluminescence methods. It was shown that Zn0.75Mg0.25O solid solution with hexagonal structure has the bandgap of Eg ∼3.65 eV. The quenching of host defect-related luminescence in ZnO:Mn and in hexagonal Zn0.75Mg0.25O:Mn was observed, while the Mn-related emission being absent. The energy level of MnZn2+ center in hexagonal Zn0.75Mg0.25O:Mn was found to be at 2.16 eV below conduction band (c-band) bottom and all excited states of MnZn2+ ions, including the lowest one, reside in c-band, as it takes place in ZnO:Mn. It is concluded that the necessary condition to obtain Mn-related light emission in Mn-doped alloys is to make deeper the lowest excited level of MnZn2+ ions. One of the solutions is to produce Zn1-xMgxO:Mn solid solution with the bandgap energy larger than 4.0 eV using nonequilibrium fabrication approaches.

Insight on the structural, electronic and optical properties of Zn, Ga-doped/dual-doped graphitic carbon nitride for visible-light applications

The density functional theory (DFT) was applied for the first time to study the doping and co-doping of Ga and Zn metals on graphitic carbon nitride (g-C3N4). The doping of these metal impurities into g-C3N4 leads to a significant decrease in the bandgap energy. Moreover, the co-doping leads to even lower bandgap energy than either individual Zn or Ga-doped g-C3N4. The theoretical electronic and optical properties including the density of state (DOS), energy levels of the frontier orbital, excited state lifetime, and molecular electrostatic potential of the doped and co-doped g-C3N4 support their application in UV–visible light-based technologies. The quantum mechanical parameters (energy band gap, binding energy, exciton energy, softness, hardness) and dipole moment exhibit higher values (ranging from 1.36 to 4.94 D) compared to the bare g-C3N4 (0.29 D), indicating better solubility in the water solvent. The time-dependent DFT (TD-DFT) calculations showed absorption maxima in between the UV–Vis region (309–878 nm). Additionally, charge transfer characteristics, transition density matrix (TDM), excited state lifetime and light harvesting efficiency (LHE) were investigated. Overall, these theoretical studies suggest that doped and co-doped g-C3N4 are excellent candidates for electronic semiconductor devices, light-emitting diodes (LEDs), solar cells, and photodetectors.

Effect of the Elaboration Method on Structural and Optical Properties of Zn1.33Ga1.335Sn0.33O4:0.5%Cr3+ Persistent Luminescent Nanomaterials.

Near-infrared (NIR) persistent luminescence (PersL) materials have demonstrated promising developments for applications in many advanced fields due to their unique optical properties. Both high-temperature solid-state (SS) or hydrothermal (HT) methods can successfully be used to prepare PersL materials. In this work, Zn1.33Ga1.34Sn0.33O4:0.5%Cr3+ (ZGSO:0.5%Cr3+), a newly proposed nanomaterial for bioimaging, was prepared using SS and HT methods. The results show the crystal structure, morphology and optical properties of the samples that were prepared using both methods. Briefly, the crystallite size of the ZGSO:0.5%Cr3+ prepared using the SS method is ~3 µm, and as expected, is larger than materials prepared using the HT method. However, the growth process used in the hydrothermal environment promotes the formation of ZGSO:0.5%Cr3+ with more uniform shapes and smaller sizes (less than 500 nm). Different diameter ranges of nanoparticles were obtained using HT and ball milling (BM) methods (ranging from 25-50 nm) and by using SS and BM methods (25-200 nm) as well. In addition, the SS-prepared microstructure material has stronger PersL than HT-prepared particles before they go through ball milling to create nanomaterials. On the contrary, after BM treatment, ZGSO:0.5%Cr3+ HT and BM NPs present higher PersL and photoluminescence (PL) properties than ZGSO:0.5%Cr3+ SS and BM NPs, even though both kinds of NPs present worse PersL and PL compared to the original particles before BM. To summarize: preparation methods, whether by SS or HT, with additional grinding as a second step, can have a significant impact on the morphological and luminescent features of ZGSO:0.5%Cr3+ PersL materials.

Influence of deposition temperature on structure and optical properties of spray pyrolyzed Zn0.97Nd0.03O thin films

The addition of a suitable dopant to the host matrix can alter the structure and optical characteristics of the nanostructures. Here, we studied the influence of deposition temperature on the structural and optical properties of Zn0.97Nd0.03O thin film prepared on a glass substrate using the spray pyrolysis method. The structural study revealed that XRD peak intensity decreased as deposition temperature increased, and the prominent peak intensity shifted from the (101) plane to the (002) at higher temperatures. With increasing temperature, the estimated crystallite size reduced from 16.34 to 12.12 nm. The bandgap value decreased (3.24–3.07 eV) with an increase in the deposition temperature. The photoluminescence spectra contained the peaks corresponding to Deep Level Emissions (DLE) along with Near Bandedge Emission (NBE). Thus, our findings emphasize the important role of deposition temperature in controlling and adjusting the structural and optical features of ZnO nanostructures.

Role of ZnO and MgO interfaces on the growth and optoelectronic properties of atomic layer deposited Zn1−xMgxO films

Zn1−xMgxO films with very precise Mg content are of strong interest for the development of buffer layers on copper-indium-gallium-sulfide solar cells. Atomic layer deposition (ALD) has been successfully used for buffer layers with appropriate electronic properties; however, a good understanding of the growth properties of the ternary oxide is still lacking. Here, we investigate the role of the ZnO/MgO interface on the growth and resulting optoelectronic properties by varying the supercycle parameters (pulse ratio and bilayer period) of the ALD process. We demonstrate that the growth of the MgO layer is enhanced by the ZnO surface, describing the interplay between ZnO and MgO interfaces on the growth of Zn1−xMgxO films. The optical properties of the film not only depend on the Mg content but also on the bilayer period at a given Mg content. More specifically, the bandgap for a given Mg composition is high for the smallest bilayer period 5, starts decreasing slightly for bilayer periods between 10 and 20 due to the increase in thickness of the ZnO layer and confinement effects, and falls to a bandgap of ZnO as the bilayer period increases further >40. With the change in Zn1−xMgxO films from well-mixed to multilayer material as the bilayer period is varied, we illustrate that the optical properties of Zn1−xMgxO can be tuned effectively without largely altering the composition. Probing the effect of the bilayer period on the ternary oxides by ALD is a useful tool in understanding the mixing and interplay of binary materials that can be applied for many other materials.

Investigation of defect structure and optical properties of Zn:Dy:$$\mathrm{LiNbO}_3$$ crystals with different [Li]/[Nb] ratios

Investigation of defect structure and optical properties of Zn:Dy:$$\mathrm{LiNbO}_3$$ crystals with different [Li]/[Nb] ratios

First principles calculations of structural, electronic and optical properties of Sn-doped ZnS

Using the full potential linearized augmented plane wave approach within the density functional theory (DFT), the structural, electronic and optical properties of Zn1−xSnxS (x= 6.25, 12.5 and 25%) solid solutions in most stable cubic phase of ZnS are computed. The bandgap values are calculated by using Tran–Blaha approach of modified Becke and Johnson (TB-mBJ) local spin density approximation. For Sn-doped ZnS, the compounds are non-magnetic indirect bandgap semiconductors with narrow bandgaps. The contribution of the Sn-5p state near Fermi level in the valance band reduces the bandgap of the doped systems. Optical characteristics are estimated using the dielectric function spectra as well as other associated optical properties such as absorption coefficient, reflectivity, refractive index, extinction coefficient and conductivity. The investigation shows that this compounds might be a good choice for optoelectronic devices.

Unique Luminescence Properties in Zn2+-Doped CsPbBr3 Perovskite Nanocrystals

All-inorganic halide perovskite (CsPbX3) is a photoelectric material with great potential. However, the Pb element in CsPbX3 is toxic, which affects the further use of these materials. The toxicity problem can be solved by adding Zn ions into CsPbBr3. In this work, Zn-doped cesium lead bromide perovskites (CsPbBr3) nanocrystals (NCs) were synthesized by thermal injection method, and their optical properties were also studied. When Zn was introduced into CsPbBr3, its exciton emission summit shifts slightly. By changing the concentration of Zn[Formula: see text], the size and optical properties of Zn:CsPbBr3 NCs can be controlled. We also study the decay lifetime of its emission peak, and the results showed that Zn:CsPbBr3 had a longer PL decay lifetime than undoped CsPbBr3. This indicated that the incorporation of CsPbBr3 into Zn[Formula: see text] had a good application prospect in the optical field.

Correction to: Investigations on electronic and optical properties of Zn:CdO‑PVDF polymer composite thin films

Correction to: Investigations on electronic and optical properties of Zn:CdO‑PVDF polymer composite thin films

Investigations on electronic and optical properties of Zn:CdO-PVDF polymer composite thin films

Investigations on electronic and optical properties of Zn:CdO-PVDF polymer composite thin films

Effect of Mg2+ ions substitution on phase formation, structural, morphological, and optical properties of Zn0.1−xMgxO structure

Effect of Mg2+ ions substitution on phase formation, structural, morphological, and optical properties of Zn0.1−xMgxO structure

Structure and optical properties of Zn and Mn co-doped nano-NiFe2O4

Structure and optical properties of Zn and Mn co-doped nano-NiFe2O4

Interface and optical properties of Zn1−xMgxO films with Mg content of more than 70% grown on the (12̄10)-ZnO substrates

Fabricating Zn1−xMgxO films with a high Mg content is key to their applications in deep-ultraviolet optoelectronic devices. In this work, we report the preparation of Zn1−xMgxO films on (12̄10)-ZnO substrates by molecular beam epitaxy. The Zn1−xMgxO/(12̄10)-ZnO structure is revealed by x-ray diffraction and high-resolution transmission electron microscopy. Remarkably, no cubic MgO is observed for films with 74.6% Mg content; the film shows mainly the wurtzite structure with some intermediate phases at the interface. Photoluminescence spectra show that the film exhibits good optoelectronic properties with a bandgap of 4.6 eV. This work provides a new avenue for the fabrication of deep-ultraviolet Zn1−xMgxO films.

Improved Doping and Optoelectronic Properties of Zn-Doped Cspbbr3 Perovskite through Mn Codoping Approach

Reducing the toxic Pb component in perovskites is an important step to realize environment-friendly perovskite optoelectronic devices. Herein, the structural, electronic, and optical properties of Zn and Mn codoped CsPbBr3 have been investigated based on first-principle calculations and experimental verifications. Although the Zn dopant could reduce the optical band gap and exciton binding energy and enhance the optical absorption and defect tolerance for CsPbBr3, the maximum reduction of the toxic Pb component was just about 12.5% in the experiment because the Zn dopant enlarges the formation energy of CsPb1-xZnxBr3. For the stable CsPb1-x-yMnxZnyBr3 perovskite, the largest y and corresponding (x + y) could reach up to 25% and 83% respectively, since the Mn dopant could reduce the structural disorder. Especially when (x + y) < 50%, CsPb1-x-yMnxZnyBr3 exhibits a comparable carrier lifetime and exciton binding energy with a lower band gap to those of the CsPbBr3, since the Zn dopant supplies a charge to CsPbBr3 to counteract the variation of Pb-Br bonds induced by the Mn dopant. Meanwhile, the d orbitals of the dopant increase the optical absorption. These suggest that a 50% reduction of toxic Pb could be realized for stable CsPb1-x-yMnxZnyBr3 with negligibly deteriorated optoelectronic properties. This work provides an alternative approach to achieve a Pb-less perovskite with a high performance.

A comprehensive study on the impact of Gd substitution on structural, optical and magnetic properties of ZnO nanocrystals

Abstract We report here the impact of Gd substitution on structural, optical, photoluminescence and magnetic properties of Zn1−xGdxO (x = 0.02–0.10) nanocrystals. Rietveld refinement of PXRD patterns, SAED and FTIR analysis revealed that Zn1−xGdxO nanoparticles crystallize in single phase wurtzite type hexagonal symmetry. HRTEM & SEM analysis confirmed good crystallinity of Zn1−xGdxO nanocrystals with a wide size distribution in 10–40 nm range. Concentration of Gd3+ ions at the Zn site causes a systematic reduction in the average crystallite size of Zn1−xGdxO nanocrystals. UV-Vis-NIR and photoluminescence spectroscopic studies showed decrement in band gap energy and suppression of UV emission (391–416 nm) with Gd concentration in Zn1−xGdxO. Analysis of the visible band emission spectra demonstrated that 325 nm photoexcited Zn1−xGdxO nanocrystals emit light in the orange-red region due to formation of complex defects in the ZnO lattice. M-H curves of 2% and 4% Gd doped ZnO nanocrystals recorded at 300 K showed thin ferromagnetic hysteresis loop (almost equal Mr =~1.8 memu/g and Hc=~210 & ~136 Oe for 2% and 4% Gd doped ZnO respectively) at lower magnetic fields but in the high field range, the magnetization responded linearly with the applied magnetic fields and, thus establishes coexistence of paramagnetic and weak ferromagnetic ordering in 2% and 4% Gd substituted ZnO nanocrystals. The higher 6%, 8% and 10% Gd substituted ZnO nanocrystals are found to be paramagnetic at 300 K. At 5 K, all the samples showed S-shaped M-H curves with negligible coercivity & retentivity and the magnetization monotonically incremented (5–25 emu/g) with increasing Gd concentration in Zn1-xGdxO. Superparamagnetic clusters and antiferromagnetic states coexist in Zn1−xGdxO nanocrystals at 5 K. Magnetic and optical properties of Zn1−xGdxO nanocrystals are suitable for magneto-optoelectronic applications.

Investigation of structural and optical properties of Zn0.67Mg0.3Al2O4:0.03Dy nanophosphor

The morphological and visual properties of Zinc Magnesium Aluminate (Zn0.67 Mg0.3 Al2O4) nanophosphor impured with Dysprosium (Dy3+) of 0.03 mol were reported in the present paper. Urea (NH2-CO-NH2) was used as fuel, Zn0.67Mg0.3 Al2O4(Pure)& Zn0.67Mg0.3 Al2O4 doped with 0.03 mol of Dysprosium (Dy3+) nanophosphors were synthesized through a solution combustion technique. The emergence of Zn1−xMgx Al2O4(Pure) & Zn1−x−yMgxAl2O4:YDy (x = 0.3 & Y = 0.03 mol) were confirmed by urea-nitrate incorporation through combustion synthesis manner at 550 °C. The morphological properties of Pure and impure ZnMgAl2O4 nanocrystallites were investigated through X-ray diffraction (XRD) having Cu Kα [40 kV, 15 mA X-ray] at λ = 1.541862°A, the stage recognization and interposed stage emergence were established through the appearance of the heterojunctions peak at 2θ = 36.68◦ and Fourier Transform Infrared (FT-IR) Spectroscopy (PEService). An Optical energy gap(Eg) of 1.499 eV calculated by Tauc Plot Method confirmed that Zn1-x-yMgxAl2O4, may be semiconducting materials. The result proved that the Zn-MgAl2O4 with an average particle size of 25.12 nm and 24.90 nm for pure and impure nanophosphors are crystalline in nature. The nanophosphors size were calculated by Scherer’s equation.

Structural, electrical and optical properties of Zn1−xCuxO (x = 0.00–0.09) nanoparticles

Pure and copper doped zinc oxide nanoparticles (Zn1−xCuxO) of different concentrations (x = 0.0, 0.03, 0.06 and 0.09 wt%) were synthesized by using co precipitation method. During the next phase, effect of Cu concentration on structural, electrical and optical properties of ZnO-NPs were investigated with the multiple techniques like XRD, UV–visible spectroscopy, FTIR, and two probe methods. The XRD analysis confirmed hexagonal wurtzite crystal structure having crystallite sizes ranging between 18.3 and 24.2 nm. Rotational and vibration mode of different functional groups (OH, CH, C = O and ZnO) were calculated using FTIR spectra. Moreover, the UV visible spectroscopy identified a band gap (3.10–2.30 eV) of pure and Cu doped ZnO-NPs. Finally, electrical properties like conductivity was increased and whereas, the resistivity decreased with increasing Cu dopant concentrations. Overall, addition of Cu as doping agent improved the structural, optical and electrical properties ZnO-NPs and could enable multiple further potential applications like solar cell, energy storage and other optoelectronic devices.