Optical Properties Of Mg Research Articles

Structural and optical properties of Mg doped TiO2 nanoparticles synthesized by sol-gel method

Pure and doped titanium oxide (TiO2) nanoparticles with various atomic wt% (0 %, 3 %, 5 % and 7 %) of Mg were prepared by sol-gel method followed by the calcination at 100 °C for 12 h to investigate structural, optical and photoluminescence properties of TiO2 nanoparticles. Subsequently prepared samples annealed at 400 °C for 2 h for crystallization. Eventually, as prepared samples have been characterized using X ray diffractometer, scanning electron microscopy (SEM), Fourier transform Infrared Spectroscopy (FTIR), UV–Visible spectroscopy and Photoluminescence spectroscopy. XRD analysis shows that, prepared samples are crystalline in nature with exhibit of mixed phase (Rutile and Anatase) of TiO2. The crystallite size obtained around 12.0 nm of pure TiO2 nanoparticles. As increase in the doping concentration crystallite size was reduced to 6.76 nm. SEM images demonstrate the uniform growth of nanoparticles. Doping offering the tuning the energy band gap of TiO2. Photoluminescence spectra observed near UV to visible region. The intensity of Photoluminescence emission enhanced with increase of Mg doping at various concentration. Band gap and photoluminescence emission properties of doped TiO2, can be useful for optoelectronic applications and as Photo catalyst. The possible mechanism of coordination for different properties for TiO2 nanoparticles with various doping concentration have been well discussed.

Influence of green laser light on the structural and optical properties of Mg-, Mn-, and Mn + Mg-doped copper oxide nanoparticles prepared by spin coating

Influence of green laser light on the structural and optical properties of Mg-, Mn-, and Mn + Mg-doped copper oxide nanoparticles prepared by spin coating

Investigation of structural and optical properties of Mg doped ZnS thin films prepared by Mist-CVD technique: Experimental and theoretical aspects

In the present study, undoped and magnesium (Mg)-doped zinc sulfide (ZnS) thin films were prepared using the low-cost Mist CVD technique on a soda-lime glass substrate in a reactor chamber maintained at a high temperature of 450 °C ± 10 °C. The structural, vibrational, chemical compositional, morphological, optical and electric characteristics of the prepared Zn1-xMgxS thin films were studied using X-ray diffraction (XRD), Raman spectroscopy, energy dispersive spectrometer (EDS), scanning electron microscopy (SEM), photoluminescence emission (PL), atomic force microscopy (AFM) analysis, and Hall effect measurements. The aim of the present work is to examine the effect of incorporation of Mg into ZnS thin films matrix. XRD and Raman spectroscopy investigations confirmed the formation of polycrystalline micro structured films. The presence of Zn, S, and Mg elements was confirmed by EDS Analysis. The growth of the surface roughness of the films with increasing Mg content, as well as the crystalline size lead to a higher carrier concentration (5.103 × 1018 cm−3), and lower resistivity of the thin films (5.021 × 10−3 Ω cm). Furthermore, DFT investigation of the electronic properties using the GGA/PBE + U functional provides a detailed explanation of the band structure and confirms the band gap reduction after doping wurtzite ZnS with Mg (12 at.%). Therefore, the outcome of this of this study might provide an experimental and theoretical background for future research on Mg-doped ZnS.

Fabrication and characterization of sputtered Mg and F co-doped ZnO thin films with different substrate temperature for silicon thin-film solar cell applications

Transparent conducting oxide thin films have been extensively studied for various optoelectronic devices. In this paper, we investigated the influence of substrate temperature on structure, morphology, electrical and optical properties of Mg and F co-doped ZnO (MFZO) thin films. The MFZO films were deposited on glass substrates by radio frequency magnetron sputtering at a temperature ranging from room temperature to 200 °C. Experimental results indicate that small amounts of Mg (3 at%) and F (6 at%) co-doping does not change the (002) oriented hexagonal wurtzite structure of ZnO, but it can improve the crystallinity and optoelectronic properties by increasing the substrate temperature. For all MFZO films, the average transmittance in the visible region exceeds 91%. As the substrate temperature rises to 200 °C, the electrical resistivity of the film drops to 1.18 × 10−3 Ω cm. The high figure of merit (FOM) of the film deposited at 200 °C, 1.36 × 10−2 Ω−1 or 2.96 × 104 Ω−1 cm−1, makes it a transparent conductor of choice for photovoltaic applications. By etching with a dilute HCl solution, the surface morphology of the as-deposited MFZO film was modified to a crater-like texture, resulting in a significant increase in the average haze in the visible region from 4.5% to 52.3%. By employing the developed high-FOM and high-haze MFZO film as the front electrode of a-Si:H thin-film solar cells, a 30% increase in conversion efficiency was achieved under AM 1.5 G illumination.

The effect of electronegativity on optical properties of Mg doped ZnO

In this work, ZnO thin films are deposited on glass substrates by sol gel spin coating technique and doped at different concentration of Mg (1%, 2%, 3%, 4%, and 5% Mg). The structural, morphological and optical properties of ZnO doped Mg are investigated for improved thin film solar cell performance. The DRX result exhibit that once the Mg atoms was introduced in the ZnO structure, the peaks take a preferential orientation according to the (002) plane, reaching a maximum value at 2% Mg. This behavior has been attributed simultaneously to the difference of electronegativity between Zn and Mg, and variation of grain size.The variation of electronegativity affected also the optical properties where the transmittance reaches its maximum value of 90%at 3% Mg concentration. The gap energy reaches the maximum value in a sample with the highest crystallite size and the highest preferential orientation, which corresponds, to ZnO: 2% Mg.

Synthesis of TiO2-based photoelectrode and natural dye for dye sensitized solar cell (DSSC)

Synthesis and characterization of Mg and La doped TiO2 photoelectrodes and natural dye have been studied. This study aimed to analyze the effect of Mg and La concentration on the characteristics of Mg and La doped TiO2 and to investigate the characteristic of natural dye extracted from green spinach, red spinach, and mangosteen rind. Mg and La doped TiO2 were synthesize by sol-gel method using titanium (IV) isopropoxide, magnesium acetate and lanthanum (III) acetate as precursors. The concentration of Mg and La were varied from 0 – 4% mol. Mg and La doped TiO2 films were deposited on glass substrate by using doctor blade technique and annealed at 500°C for 1 h. The films were then characterized using X-Ray Diffractometer and UV-Vis spectrometer measurement to investigate its characteristics. The results showed that dopant concentration strongly affected the structural and optical properties of Mg and La doped TiO2. The UV-Vis measurement of the natural dye extracted from green spinach, red spinach, and mangosteen rind showed a different absorption spectrum. However, FTIR measurement of these dyes showed relatively the similar spectrum. This shows that each dye has different optical properties, even though it has relatively the same functional group.

Effect of spray drying treatment on the optical properties of Mg–Al spinel ceramics

In recent years, Mg–Al spinel ceramic has been in the spotlight due to its large transparency range and good mechanical properties. The aim here, was to control the state of agglomeration of powder to improve densification behaviour and consequently optical and mechanical properties of the ceramics. Commercial powder with a small particle size was used and exhibits poor flowability, which was found to be detrimental to shaping and led to a translucent ceramic with an opaque crown. The powder was granulated by spray drying and the influence of the molecular mass of added polyethylene glycol on the granulate size, compaction and finally sintering behaviour was investigated. Special attention was paid to the differences in rheological behaviour of powders, which was thoroughly characterized with a FT4 powder rheometer. Agglomeration of powder improved in-line transmission at 650 ​nm up to 71% compared to 3% for ceramic from as-received powder.

Electronic structure, dynamic stability, elastic, and optical properties of MgTMN2 (TM = Ti, Zr, Hf) ternary nitrides from first-principles calculations

Ternary nitride semiconductors with tunable electronic structure and charge transport properties have attracted increasing attention as optoelectronic materials. The recently discovered ternary MgTMN2 (TM=Ti,Zr,Hf) are predicted to be nondegenerate semiconductors with visible-range optical absorption onsets. In the present study, the electronic structure, elastic properties, optical absorption spectrum, and dynamic stability of the MgTMN2 system have been systematically studied by first-principles calculations based on the density functional theory. These compounds show semiconductor characteristics with a bandgap ranging from 1.0 to 1.5 eV predicted by the Heyd–Scuseria–Ernzerhof approach. Compared to the traditional semiconductors of Si and GaAs and III–V nitrides of GaN and AlN, these ternary nitrides have stronger resistance to external compression, shear strain, and deformation due to the larger elastic modulus. MgTiN2 shows a strong anisotropy characteristic along the xy plane and z axis, while for MgZrN2 and MgHfN2, a weak elastic anisotropy is predicted. The absorption regions of these compounds are mainly concentrated in the ultraviolet region, and MgTiN2 is more sensitive to visible light with respect to the other two compounds. The thermodynamic stability of MgTiN2, MgZrN2, and MgHfN2 is verified by the stable phonon dispersion relations. It is found that the most stable low Miller index surface is (110) for MgTiN2 and (100) for MgZrN2 and MgHfN2.

Fabrication of Transparent Mg(OH)2 Thin Films by Drop-Dry Deposition.

Magnesium hydroxide (Mg(OH)2) thin films were deposited by the drop-dry deposition (DDD) method using an aqueous solution containing Mg(NO3)2 and NaOH. DDD was performed by dropping the solution on a substrate, heating-drying, and rinsing in water. Effects of different deposition conditions on the surface morphology and optical properties of Mg(OH)2 thin films were researched. Films with a thickness of 1−2 μm were successfully deposited, and the Raman peaks of Mg(OH)2 were observed for them. Their transmittance in the visible range was 95% or more, and the bandgap was about 5.8 eV. It was found that the thin films have resistivity of the order of 105 Ωcm. Thus, the transparent and semiconducting Mg(OH)2 thin films were successfully prepared by DDD.

Microstructural and optical properties of high-quality Mg–Zn oxide thin films

The microstructural and optical properties of Mg–Zn oxide thin films deposited by aerosol assisted chemical vapor deposition onto fused silica substrates were studied as a function of the Mg concentration in the precursor solution, which was varied from 0 to 100 mol %. The thickness of all the samples was around 150 ± 20 nm. Scanning electron microscopy and grazing incidence x-ray diffraction were used for the analysis of the morphology, composition, and crystalline structure. Outcomes showed a gradual evolution of the microstructural and optical properties of the films as the Mg content increased. The systematic increase of the lattice parameter a, and the decrease of parameter c were observed with the increase of Mg concentration, nevertheless, the unit cell volume remained nearly constant, around 0.0471 ± 0.0007 nm3. Energy dispersive x-ray microanalysis results indicated that Mg /(Zn + Mg) atomic ratio (x) up to 0.59 was found for a single-phase hexagonal MgxZn1-xO film. This value is higher than most of the reported Mg content in wurtzite ZnO. At higher Mg loadings (>70 mol % in solution), the segregation of periclase MgO phases occurred. X-ray photoelectron spectroscopy confirmed the composition of selected Mg doped ZnO films and the substitution of Zn+2 by Mg+2 atoms. The Williamson-Hall analysis of diffracted peaks was employed to determine the micro-strain in the films, it was found ∈ = 0.2 ± 0.1 % with a slight tendency to decrease ∈ as x increases. For single-phase hexagonal MgxZn1-xO films, the computation of the dispersion relations of the optical constants was achieved using direct transmittance and near-normal absolute reflectance. For this objective, TFcalc software was used to fix the Sellmeier dispersion relation parameters by fitting the modeled transmittance and reflectance spectra of the stack film-substrate with corresponding experimental spectra. A detailed analysis of the optical band gap energy and its correlation with the microstructural characteristics of the films was performed, in particular with lattice parameters. The modification of optical band gap energy and lattice parameters with the inclusion of Mg in the wurtzite structure can be explained because the MgO4 unit has a compressed tetrahedral geometry with a much shorter height than those of ZnO4 tetrahedra, and due to the change in electronegativities and ionic radius between Mg and Zn, the bonding character becomes more ionic, and the increased localization of Zn 3d and O 2p orbitals. The optical band gap energy was tuned by changing the Mg content, from about 3.3 eV of undoped ZnO up to 4.3 eV of hexagonal MgxZn1−xO (x ~ 0.59). Moss relation was used to analyze the relationship of optical band gap energy and refractive index.

Structural and optical properties of Mg modified ZnO nanoparticles: An x-ray peak broadening analysis

The structural, microstructural, and optical properties of Mg-doped ZnO nanoparticles prepared via. thermal decomposition route. The Rietveld analysis was executed for prepared sample, which revealed that the hexagonal wurtzite structure for all samples along with changes in lattice parameters and bond length. The various relevant parameters, such as strain, stress, and energy density, are analyzed using different improved forms of W-H equations via. a complete Willamson-Hall (W-H) method. Scanning electron microscopy (SEM) analysis resultant that the synthesized nanoparticles (NP's) are nearly spherical for Zn 1-x Mg x O, up to x = 0.04, and transform into a rectangular shape for x = 0.10. UV–Visible spectroscopy revealed an observation of fundamental absorption peak around 375 nm, which further shifted towards the higher wavelength, recommended the blue shift in the bandgap energy. The photoluminescence (PL) studies show a green emission band at 550 nm, demonstrating the occurrence of oxygen vacancy defects in the lattice of ZnO. Zn 1-x Mg x O (0≤ × ≤0.10) nanoparticles have been prepared by the thermal decomposition method. Structural, microstructural, and optical properties of ZnO nanoparticles were examined under the ‘Mg’ doping. X-ray diffraction pattern obtained for Zn 1-x Mg x O (0≤ × ≤0.10) confirms its hexagonal wurtzite structure. The Rietveld analysis performed for a prepared sample revealed that the lattice parameters and bond length are enhanced by increasing Mg%. The various relevant parameters, such as strain, stress, and energy density, are analyzed using different improved forms of W-H equations by a complete Willamson-Hall (W-H) method. Scanning electron microscopy (SEM) analysis derived that the synthesized nanoparticles(NP's) are nearly spherical for Zn 1-x Mg x O, up to x = 0.04, and transform into a rectangular shape for x = 0.10. UV–Visible spectroscopy revealed an observation of fundamental absorption peak around 375 nm, which further shifted towards the higher wavelength, recommended the blue shift in the bandgap energy. FTIR analysis Validate the existence of Zn-O stretching mode due to the presence of absorption modes in 400–600 cm −1 for all the samples. The photoluminescence (PL) studies show a green emission band at 550 nm, demonstrating the occurrence of oxygen vacancy defects in the lattice of ZnO. • XRD and Rietveld refinement confirms the hexagonal wurtzite structure for all samples. • A small variations in lattice parameters provoked by Mg doping. • Through Willamson-Hall approach strain, stress and energy density were calculated. • Tailoring in bandgap energy has been found with Mg doping which is useful for optical devices. • Evidence of oxygen vacancy defects observed through PL studies.

Optical design of connecting electrodes for tandem organic light-emitting diodes.

Connecting electrodes play a crucial role to assist charge injection into the adjacent electroluminescent units in tandem organic light-emitting diodes (OLEDs). In this study, we demonstrate that Mg:Ag alloy is an effective connecting electrode for bottom- and top-emitting tandem OLEDs. Optical cavity design and simulation are also conducted to predict the luminance of tandem OLEDs. It is found that the theoretical luminance of tandem OLEDs is close to but not higher than twofold enhancement over the luminance of a single OLED optimized to the first resonance mode, which is theoretically higher than high-order resonance modes. It is also found that the optical properties of Mg:Ag connecting electrodes, while having relatively small influence on weak microcavity bottom-emitting tandem OLEDs, have large influence on strong microcavity top-emitting tandem OLEDs.

Electronics structure and optical properties of Mg(BiO2)4 and Mg (Bi0.91Ge0.083O2)4: A first principle approach

The new compounds, Mg(BiO2)4 was synthesized and structurally characterized semiconductor. Due to theoretical investigation for both of Mg(BiO2)4 and Mg(Bi0.91Ge0.083O2)4, computational tools were used. To calculated the electronic band structures, the total density of state, the partial density of state, and optical properties were used Generalized Gradient Approximation (GGA) based on the Perdew–Burke–Ernzerhoff (PBE0) using first principle method for Mg(BiO2)4. The band gap was recorded 0.545 eV which is supported for good semiconductor. The density of states was simulated for evaluating the nature of 3s, 3p for Mg, 6s 6p, 4d, and 2s, 2p for O atoms. Furthermore, the optical properties including absorption, reflection, refractive index, conductivity, dielectric function, and loss function were simulated which can account for the superior absorption of the visible light. The key point of this research to determine the activity of Ge doped by 11.0%, whereas the band gap, density of state, and optical properties were affected. Analysis of the band gap and optical properties of both of Mg (BiO2)4 and Mg(Bi0.91Ge0.083O2)4, the Ge doped shows the high conductivity than undoped.

A comparative analysis for effects of solvents on optical properties of Mg doped ZnO thin films for optoelectronic applications

Nanocrystalline Magnesium doped ZnO thin films (MgZnO) were synthesized on glass substrate using five different solvents i.e. 1-Propanol (1Pd), 2-Propanol (2Pd), Ethanol (Ed), Methanol (Md) and 2-Methoxyethanol (MEd) by sol-gel spin coating method. This study targeted the best solvent with MgZnO film for optoelectronic applications. The magnesium doping percentage was fixed at 5% for all samples to discover comparatively better doped results among different solvents. All the films synthesized by different solvents exhibited polycrystalline structure, particularly films with 1-Propanol and 2-Methoxyethanol showed preferred c-axis orientation at 180 °C pre-heating condition revealed by XRD pattern. Highest average crystallite size calculated by XRD study was for 2-Methoxyethanol solvent which possessed good crystalline quality. Crystalline quality was also confirmed by Raman analysis. FESEM images elucidated that all the films were crack free, had uniformly smooth grains and highest grain size for 2-Methoxyethanol solvent. EDS and FTIR spectra confirmed the magnesium presence in ZnO thin films for all solvents. The optical absorbance, transmittance and reflectance spectrum were analyzed by UV–vis spectroscopy. The highest transmittance (94 %), band gap value (3.36 eV) and better quality by PL analysis in comparison were found for 2-Methoxyethanol solvent. The data for optical constants were measured by spectroscopic ellipsometry. Furthermore real and imaginary parts of complex dielectric constant and energy loss functions were examined.

Improvement of optical properties of Mg doped ZnO by nanostructuring for applications in optoelectronics

We have studied the structural, optical, electronic and electrical properties of pure and Mg doped ZnO nanosheets compared to bulk ZnO, using the Density Functional Theory (DFT) within the Full Potential Linearized Augmented Plane Wave (FP-LAPW) formalism. The calculated band structure, total and partial densities of states show that the ZnO nanosheet have a large band gap than the other found in the bulk ZnO, which increases with increasing concentration of Mg. The absorption coefficient and optical transmittance show a red-shift after doping ZnO, whereas, the reflectivity and electrical conductivity are reduced. These good optical properties of ZnO nanosheets make it promising in optoelectronic devices, especially in solar cell application.

Magnesium for Dynamic Nanoplasmonics.

ConspectusThe key component of nanoplasmonics is metals. For a long time, gold and silver have been the metals of choice for constructing plasmonic nanodevices because of their excellent optical properties. However, these metals possess a common characteristic, i.e., their optical responses are static. The past decade has been witnessed tremendous interest in dynamic control of the optical properties of plasmonic nanostructures. To enable dynamic functionality, several approaches have been proposed and implemented. For instance, plasmonic nanostructures can be fabricated on stretchable substrates or on programmable templates so that the interactions between the constituent metal nanoparticles and therefore the optical responses of the plasmonic systems can be dynamically changed. Also, plasmonic nanostructures can be embedded in tunable dielectric materials, taking advantage of the sensitive dependence of the localized surface plasmon resonances on the neighboring environment. Another approach, which is probably the most intriguing one, is to directly regulate the carrier densities and dielectric functions of the metals themselves.In this Account, we discuss a relatively new metal in nanoplasmonics, magnesium, and its important role in the development of dynamic plasmonic nanodevices at visible frequencies. We first elucidate the basic optical properties of Mg and compare it with conventional plasmonic materials such as Au, Ag, and others. Then we describe a unique characteristic of Mg, i.e., its reversible phase transitions between the metallic state and a dielectric state, magnesium hydride, through hydrogenation and dehydrogenation. This sets the basis for Mg in dynamic nanoplasmonics. In particular, the structural properties and dielectric functions of the two distinct states are discussed in detail. Subsequently, we highlight the experimental investigations of the physical mechanisms and nanoscale understanding of Mg nanoparticles during hydrogenation and dehydrogenation. We then introduce a plethora of newly developed Mg-based dynamic optical nanodevices for applications in plasmonic chirality switching, dynamic color displays with Mg nanoparticles and films, and dynamic metasurfaces for ultrathin and flat optical elements. We also outline strategies to enhance the stability, reversibility, and durability of Mg-based nanodevices. Finally, we end this Account by outlining the remaining challenges, possible solutions, and promising applications in the field of Mg-based dynamic nanoplasmonics. We envision that Mg-based dynamic nanoplasmonics will not only provide insights into understanding the catalytic processes of hydrogen diffusion in metals by optical means but also will open an avenue toward functional plasmonic nanodevices with tailored optical properties for real-world applications.

Optically addressing interaction of Mg/MgO plasmonic systems with hydrogen

Magnesium-based films and nanostructures are being studied in order to improve hydrogen reversibility, storage capacity, and kinetics, because of their potential in the hydrogen economy. Some challenges with magnesium (Mg) samples are their unavoidable oxidation by air exposure and lack of direct in situ real time measurements of hydrogen interaction with Mg and MgO surfaces and Mg plasmonic nanoparticles. Given these challenges, the present article investigates direct interaction of Mg with hydrogen, as well as implications of its inevitable oxidation by real-time spectroscopic ellipsometry for exploiting the optical properties of Mg, MgH2 and MgO. The direct hydrogenation measurements have been performed in a reactor that combines a remote hydrogen plasma source with an in situ spectroscopic ellipsometer, which allows optical monitoring of the hydrogen interaction and results in optical property modification. The hydrogen plasma dual use is to provide the hydrogen-atoms and to reduce barriers to heterogeneous hydrogen reactions.

Optical Properties of Mg- and Ni- Doped Ag2S Colloidal Nanoparticles

In this work, we report the optical properties of Mg- and Ni-doped Ag2S colloidal nanoparticles. The Mg- and Ni-doped Ag2S nanoparticles were prepared using a wet chemical method. The influence of doping on the optical properties of the Mg- and Ni-doped Ag2S nanoparticles was investigated. The transmission electron microscopy (TEM) images showed the shapes of particles to be spherical with an average particle size of about 5–18 nm for all pure and doped Ag2S nanoparticles. The absorption spectra of the Mg-doped samples were red shifted from 2.42 to 2.20 eV, however, the UV-vis spectra of the Ni-doped Ag2S showed a blue shift from 2.42 to 2.60 eV. The observed blue shift in the band gap of Ni-doped Ag2S may be due to the substitution of Ni in to the Ag2S lattice. The photoluminescence intensity of the Mg-doped Ag2S nanoparticles increased as the Mg concentration was increased. However, the photoluminescence (PL) intensity of the Ni-doped Ag2S decreased as the concentration of Ni was increased.

Structural and optical properties of Mg doped ZnS quantum dots and biological applications

Zn1−xMgxS (x = 0, 0.2 and 0.4) quantum dots (QDs) were prepared by co-precipitation method. The Mg dopant did not modify the cubic blende structure of ZnS QDs. The Mg related secondary phase was not detected even for 40% of Mg doping. The size mismatch between host Zn ion and dopant Mg ion created distortion around the dopant. The creation of distortion centres produced small changes in the lattice parameters and diffraction peak position. All the QDs showed small sulfur deficiency and the deficiency level were increased by Mg doping. Band gap of the QD was decreased due to the dominated quantum confinement effect over compositional effect at initial doping of Mg. But at higher doping the band gap was increased due to compositional effect, since there was no change in average crystallite size. The prepared QDs had three emission bands in the UV and Visible regions corresponding to near band edge emission and defect related emissions. The electron transport reaction chain which forms free radicals was broken by sulfur vacancy trap sites. Therefore, the ZnS QDs had better antioxidant activity and the antioxidant behaviour was enhanced by Mg doping. The enhanced UV absorption and emission of 20% of Mg doped ZnS QDs let to maximize the zone of inhibition against E. Coli bacterial strain.

Exposition of structural, microstructural and optical properties of Mg and Zr doped BiFeO3 for profound optoelectronic device applications

Magnesium (Mg) and zirconium (Zr) doped bismuth ferrite (BiFeO3; BFO) ceramics such as Bi1−xMgxFeO3 (Mg doped BFO; BMO), BiFe1−xZrxO3 (Zr doped BFO; BZO) and Bi1−xMgxFe1−xZrxO3 (both Mg and Zr dope...