Decrease In Optical Band Gap Research Articles

Optical properties of as-deposited, annealed and laser-treated Ge2Sb2Te5 thin films

Knowledge of the correct optical properties of phase change materials (PCM) is important in the development of many devices. Here, we report on the differences in optical properties of as-deposited, annealed, laser-reamorphized and laser-recrystallized G e 2 S b 2 T e 5 thin films. While as-deposited and laser-reamorphized G e 2 S b 2 T e 5 show a similar spectral dependences of refractive indices and extinction coefficients with a small decrease in optical band gap from 0.63 to 0.59 eV, spectral dependences of annealed and laser-recrystallized G e 2 S b 2 T e 5 differ significantly from each other in the entire measured spectral region with values of optical band gap 0.51 and 0.45 eV, respectively. We discuss the main differences in the optical functions between both crystalline phases using X-ray diffraction studies. We further present that the laser-reamorphized phase transforms to the crystalline phase at about 12 °C lower temperature in contrast to the as-deposited amorphous phase.

Structural, optical, and dielectric modulus properties of PEO/PVA blend filled with metakaolin

The PEO/PVA blend incorporated by different weight percentages (≤10%) of metakaolin (MK) has been prepared and characterised. The XRD revealed a semicrystalline structure of pure PEO/PVA with peaks indicating the presence of silicon and aluminum in the MK composition. The addition of MK in the blend leads to a decrease in the diffraction peak intensities, confirming that the blend-MK interactions break some PEO/PVA blend domains. The UV–Vis transmittance and reflectance spectra were studied and used to determine optical parameters. The decrease in the band-gap values was demonstrated with the increase in MK to confirm the suitability of MK as a band-gap regulated the optical material in different applications. The obtained values of the optical band gap decrease with the increase of MK concentration due to the defect levels that correlate to the sample's density of localized states. The higher values of ε′ found at a lower frequency related to the effect of the dominant contribution of the interfacial polarization due to the accumulation of charges, whereas the higher values of ε″ at the lower frequency were related to an increase in the energy loss in the composite films. The Cole-Cole plot displays semicircles at the lower frequency range with a linear increase at the intermediate and higher frequency due to the grain boundary and the relaxation process. The values of the real part (σ′) are lower than that of the corresponding values of the imaginary part (σ″). Applied an electric field causes polarized films and the ability to store an electric charge. Therefore, these composites may be used in flexible capacitors.

Increase in nonlinear susceptibility and refractive index in quaternary In15Sb10S15Se60 thin films upon annealing at different temperature for photonic applications

The current paper reports the thermal annealing induced amorphous to crystalline transformation of the quaternary In15Sb10S15Se60 thin films prepared by the thermal evaporation method on glass substrate. The prepared films were annealed at 100 °C, 150 °C, 200 °C, and 250 °C under vacuum conditions. The structural characterization was done by X-ray diffraction and Raman spectroscopy which revealed the amorphous to crystalline transformation and the formation of different phases for the annealed films. The composition of the films was verified by Energy dispersive X-ray analysis, whereas the surface morphology pictures were taken by field emission scanning electron microscopy and atomic force microscope. The changes in both linear and nonlinear optical properties of as-prepared and annealed films were studied from UV-Vis spectroscopy data and related empirical formula. The significant reduction in transmission (55–4%) and shifting of absorption edge due to annealing resulted in the decrease of optical bandgap (from 1.641 eV to 1.301 eV) and increase in linear refractive index. The 3rd order nonlinear susceptibility (9.83 ×10−15 to 2.44 ×10−11 esu) and nonlinear refractive index (4.59 ×10−13 to 6.01 ×10−10 esu) were found to be increased due to more polarization effect. The role of annealing temperatures on the variation of different parameters was elaborately explained on the basis of amorphous to crystalline transition and defect states in the localized region. Based on the observed changes in the linear and nonlinear optical parameters by thermal annealing, the In15Sb10S15Se60 thin films could be a suitable candidate for numerous photonic and optoelectronic applications.

Investigation of structural, magnetic, and electrical properties of Ru doped brownmillerite oxide: KBiFe2O5

We studied and reported the Ruthenium (Ru) doped KBF (KBiFe2O5) multiferroic nanoparticles on structurl, magneitc and electrical properites as a function of dopant and temperature, synthesized through coprecipitation route. X-ray Diffraction spectra of all the samples were indexed with orthorhombic structure (space group P21am) at room temperature and lattice constant decreased with Ru substition. The structural parameters including bond lengths and angles were refined using a standard Rietveld program. Average crystallite measured from schereer method increases with increasing annelaing temperature. Morphology from TEM confirms control over uniform distribution of particle size and shape. Zero field-cooled (ZFC)-Field-Cooled (FC) magnetic measurements reveals superparamagnetic behaviour above room temperature. Magnetic hysteresis loops (M − H) measured at 5 K and 300 K shows improvement with Ru substitution. An insginificant decrease in optical band gap 2.35 to 2.23 eV observed from UV–Vis spectroscopy with Ru substitution. Ferroelectric loops resembling lossy dielectric nature of unpoled samples. Activation energy estimated from DC electrical resistivity was found to be 0.6 eV. Room temperature Dielectric data revelas Maxwell-Wanger type dielectric dispersion and analyzed based on the intrinsic and extrinsic parameters.

Role of tellurium addition on the linear and non‐linear optical, structural, morphological properties of Ag60‐xSe40Tex thin films for nonlinear applications

AbstractThe tellurium (Te)‐doped Ag60‐xSe40Tex (x = 0%, 5%, 10%, 15%) thin films of thickness ∼800 nm were prepared from the bulk sample by thermal evaporation method on a glass substrate. The X‐ray diffraction study revealed the amorphous nature of the films whereas the change in vibrational modes was noticed from the Raman spectroscopy. The composition of the films was verified by energy dispersive X‐ray analysis and the surface morphology pictures were taken by field emission scanning electron microscopy and atomic force microscope. The changes in optical properties (linear and non‐linear) with Te addition were studied from UV‐Visible spectroscopy data and related empirical formulas. The addition of Te reduced the bandgap values significantly and the reduction in transmission resulted in the increase of the linear refractive index. The decrease in optical bandgap is due to an increase in disorder while the width of the tail in the gap increased with Te%. The optical density, dispersion energy, extinction coefficient, carrier concentration, dielectric constant, oscillator wavelength increased while the oscillator energy, oscillator strength, optical electronegativity decreased with Te content. The electrical susceptibility increased with Te content. The non‐linear susceptibilities and the non‐linear refractive index increased which is good for the nonlinear photonic devices.

Structural, thermal, and optical properties of polyvinyl alcohol films doped with La2ZnOx nanoparticles

To investigate La2ZnOx nanoparticles, ZnO is partially substituted by lanthanum oxide (La2O3) using a tartaric acid precursor. The prepared nanoparticles were reinforced in the polyvinyl alcohol (PVA) with different content and the films were obtained by casting method. The impact of the nanoparticles in the polymer structure and the thermal stability of the films were studied by X-ray diffraction and TGA-DTA techniques. Optical parameters were investigated using the absorbance and transmittance spectra obtained from the UV–visible spectrophotometer. Optical bandgap decreases, whereas the refractive index and optical conductivity improved with the addition of La2ZnOx nanoparticles in the polymer matrix. PVA-La2ZnOx films with enhanced futures are promising for organic-electronic applications.

Cellulose derivative/barium titanate composites with high refractive index, conductivity and energy density

This work deals with hydroxypropyl cellulose (HPC)/barium titanate (BT) composites, having small levels of perovskite-like BT loading, i.e. 0.5–2% and being designed for electric energy storage applications. The films were obtained by solution “casting method and their structural properties were confirmed by FTIR. Scanning Electron Microscopy scans reveal that ceramic filler is well and uniformly dispersed within the cellulosic matrix. UV–VIS spectroscopy data indicate a slight increase of the absorption and the decrease of optical band gap from 5.71 eV for the HPC matrix (0% BT) to 5.20 for the sample containing 2% BT. According to refractometry analyses, the presence of BT particles determines an increase in sample polarizability, reflected in a higher refractive index, namely 1.533 and 1.605 at 486 nm for 0% BT and 2% BT samples, respectively. The values of the dispersion energy and single-oscillator energy are decreasing after filling HPC with BT, whereas first/third order optical susceptibilities and nonlinear refractive index are increasing. Mechanical tests show that incorporation of BT particles increase the value of Young modulus from 239 MPa for pure HPC to 342 MPa for 2% BT in the matrix. Dielectric studies prove that the samples exhibit a significant change in the real part of the permittivity with filler loading, ranging from 4.2 for neat HPC up to 8.5 for HPC/BT 2%.

Spinel nickel cobaltite nanoflakes anchored multiwalled carbon nanotubes driven photocatalyst for highly efficient degradation of organic pollutants using natural sunlight irradiation

Natural sun light driven photocatalytic materials have received remarkable attention due to their imminent applications in environmental remediation and energy conversions. In this study, natural sun light driven hierarchal spinel nickel cobaltite nanoflakes (NiCo 2 O 4 ) anchored multiwalled carbon nanotubes (MWCNTs) nanocomposite was synthesized by using simple chemical route. The structural, morphological and functional group of as-prepared NiCo 2 O 4 anchored MWCNTs was studied by using X-ray diffractometry, field emission scanning electron microscopy and Fourier transform infrared spectroscopy. The UV–vis diffusive reflectance spectroscopy results demonstrated decrease in optical bandgap from 1.32 to 1.16eV compared with pristine spinel NiCo 2 O 4 nanoflakes. MWCNTs anchored NiCo 2 O 4 showed extremely good photocatalytic behavior and we verified 98% degradation of MB in 35 min under natural sun light. NiCo 2 O 4 anchored MWCNTs also confirmed its excellent stability and reusability by retaining 96% of photocatalytic efficiency after 7 cycles of operation. Improved photocatalytic behavior of NiCo 2 O 4 anchored MWCNTs nanocomposite in comparison to NiCo 2 O 4 nanoflakes is mainly attributed to excellent electron storage ability of MWCNTs which made catalyst a great acceptor. Moreover, porous structure of MWCNTs not only provides large surface area with more active sites but also increases conductivity and decreases agglomerations on the surface of material which render e - /h + pair recombination. Overall, this work shed new light for the synthesis of NiCo 2 O 4 anchored MWCNTs with enhanced photocatalytic properties.

Physical, structural and optical characterization of silica-borotellurite glasses containing vanadium and nickel ions

Silica borotellurite glasses with compositions SiO2][SiO2][SiO2]0.2}0.99{V2O5}0.01]1-z (Ni0)z (where z = 0.005,0.010,0.015,0.020 and 0.025 M fraction) had been prepared by conventional melt quenching technique. X-Ray Diffractograms spectra confirm the amorphous nature of the prepared glasses. Study of infrared (IR) spectroscopy reveals an increase in the formation of nonbridging oxygens (NBOs) as nickel concentration increases. This resulted in the decrease of density and oxygen packing density (OPD) of the glass. The observed ESR spectra confirmed that V4+ ions exist as vanadyl ion in the octahedral coordination with tetragonal compression. Based on UV–vis absorption spectra, four absorption bands have been observed with indirect optical band gap, Urbach's energy, refractive index and other optical parameters have been calculated. The Ni2+ ions were distributed with octahedral and tetrahedral coordination of the ligand field. Nevertheless, the octahedral coordination of Ni2+ dominated over tetrahedral coordination with the increase of NiO concentration consequently, confirmed the increase in NBOs from the IR spectra. These observations reflect the decrease in optical band gap, metallization criterion and the increase in Urbach's energy and refractive index.

Optical band gap modification of Ce/ZnO for visible light photocatalytic H2 production from aqueous methanol solution

Ce (0.5, 1, 2 and 3 mol%) incorporated ZnO crystallites along with bare ZnO were prepared by solution free mechanochemical method and characterized with powder XRD, HR-TEM, SEM, EDX, XPS, UV–visible and Photoluminescence (PL) spectra. The visible light photocatalytic performance of these materials was investigated for H2 evolution with the aqueous 10 vol% methanol solution under one sun conditions using solar simulator. X-ray diffraction data suggests the hexagonal wurtzite structure for Ce incorporated ZnO crystallites and due to incorporation of Ce4+ ion there is expansion in the lattice constants of ZnO, which is attributed to decreases in crystallite size. UV–visible spectra propose the decrease in optical band gap of Ce incorporated ZnO with the increase of Ce content up to 3 mol%. The XPS analysis supports the incorporation of Ce4+ in Ce/ZnO. The PL spectra suggest that, with the insertion of Ce ions into ZnO, intensity of green emission band increases, which reflects the low recombination rate of photogenerated charge carriers which is responsible for higher photocatalytic H2 production. Extent of hydrogen production is affected by calcination temperature of Ce/ZnO. 2 mol% Ce incorporated ZnO calcined at 600 °C produces 43μmolh−1g−1 of hydrogen.

Study of the modified magnetic, dielectric, ferroelectric and optical properties in Ni substituted GdFe1−x Ni x O3 orthoferrites

Polycrystalline GdFe1−x Ni x O3 (x = 0.00, 0.02, 0.04) samples was synthesised using a glycine assisted sol–gel method to investigate the enhanced magnetic and electric properties of Ni substituted GdFeO3 systems. TG-DSC analysis of prepared samples confirms that GdFe1−x Ni x O3 have good thermal stability in high temperatures. The system has been stabilized in an orthorhombic structure with space group Pbnm. The elemental composition of GdFe1−x Ni x O3 has been estimated from EDAX spectrum. The results showed oxygen deficiency on increasing the Ni substitution and it has been supported by Rietveld refinement. FE-SEM images and Brunauer–Emmett–Teller analysis reveals that GdFe1−x Ni x O3 is a highly porous material and its porosity and specific area increases with Ni substitution. Magnetic measurements indicates that the system exhibited ferrimagnetic behaviour at low temperatures and canted antiferromagnetic behaviour at room temperature. For x = 0.04 Ni content, magnetization reversal for applied field of 25 Oe has been observed. Increased coercivity of GdFeO3 with Ni substitution has been attributed to the grain size effect. From electrical point of view, dielectric permittivity of GdFeO3 has been enhanced with Ni substitution. This enhancement has been attributed to the cumulative effects of hopping of Fe2+–Fe3+ ions, grain–grain boundary contribution, and space charge polarization. The role of grain–grain boundary contribution is evident from electric modulus spectrum. The space charge effect has been realized in both impedance spectrum and dielectric loss. Temperature-dependent dielectric studies were conducted to understand the mechanisms and various aspects that contribute to the dielectric enhancement. A highly lossy capacitive nature in the P–E loop also suggests space charge effects due to Ni substitution in Fe sites. Availability of free charge carrier concentration is correlated with the optical properties of GdFe1−x Ni x O3. The decrease of optical band gap (2.5–2.21 eV) on increasing Ni content suggests the increasing electronic contribution in the system.

Efficient photocatalytic hydrogen production over Ce/ZnO from aqueous methanol solution

Ce/ZnO crystallites along with bare ZnO were prepared by solution free mechanochemical method and characterized with powder XRD, SEM, EDX, XPS, UV–Visible and Photoluminescence (PL) spectra. The visible light photocatalytic performance of these materials was investigated for H2 evolution with the aqueous 10vol% methanol solution under one sun conditions using solar simulator. X-ray diffraction data suggests the hexagonal wurtzite structure for Ce/ZnO crystallites and the incorporation of Ce4+ ion in ZnO is supported by the shifting of XRD peaks to lower Bragg angles that indicate lattice expansion. With the increase of Ce content in ZnO, the crystallite size of Ce/ZnO decreases and the specific surface area increases. UV–Visible spectra propose the decrease in optical band gap of Ce incorporated ZnO with the increase of Ce content up to 3 mol. %. The XPS analysis supports the incorporation of Ce4+ in Ce/ZnO. The PL spectra propose that, with the insertion of Ce ions into ZnO, intensity of UV emission band decreases that reflects the low recombination rate of photogenerated charge carriers, which is responsible for higher photocatalytic H2 production. The extent of hydrogen production is affected by calcination temperature of Ce/ZnO. 2 mol. % Ce incorporated ZnO calcined at 600 °C produces43 μmolh−1 g−1 of hydrogen.

Investigation of uniaxial strain in twisted few-layer MoS2

Applying strain is an effective way to change the optical properties of two-dimensional (2D) materials like molybdenum disulfide (MoS2). In this work, the technical details were provided to perform uniaxial strain measurements in the range of 0∼5% in twisted monolayer-monolayer MoS2 (tMMM), twisted monolayer-bilayer MoS2 (tMBM), twisted bilayer-monolayer MoS2 (tBMM) and twisted bilayer-bilayer MoS2 (tBBM). The redshift and splitting of the E2g1 peak in twisted few-layer MoS2 with increased strain are found by Raman spectroscopy and a Grüneisen parameter of ∼1.31 is extracted. The decrease of optical band gap in MoS2 was measured by photoluminescence (PL) spectroscopy, and it changes approximately linear with strain, which is −16.27 meV/% strain for tMMM and −14.19 meV/% strain for tBBM. The intensity of A peak in PL spectra decreases to one third of its original value with an applied strain of ∼5% for the twisted angle around 11°. However, twisted few-layer MoS2 exhibits strain relaxation at higher strain. This relaxation causes the bandgap to cease further redshift. The findings in this paper can help to better understand the effects of strain on the optical properties in twisted few-layer MoS2, and is applicable to other 2D materials.

Optical Losses of Frontal Layers in Superstrate CdS/CdTe Solar Cells Using OPAL2

In this paper, optical losses in CdS/CdTe solar cells are calculated on the basis of the designated reflective index of various frontal layers using an OPAL2 calculator for the first time. Two types of glass (0.1 mm ultra-thin Schott and 1.1 mm standard borosilicate glass) were assumed to be coated by different Transparent-Conducting-Oxides (TCOs) such as SnO2:F, ZnO:Al, and ITO forming frontal layers for CdS/CdTe solar cells in superstrate configuration. Absorption, reflectance, transmittance, and consequently optical bandgap energies are calculated as a function of common thicknesses, used in the literature. The results show that an increase in TCO thickness led to a decrease in optical band gap as well as an enhancement in contact potential difference, which can deteriorate device performance. The optimum thickness of 100 nm for SnO2:F was calculated, while 200 nm for ZnO:Al and ITO show reasonable optical losses caused by reflections at the interfaces’ and the layer’s absorption. It is seen that 80 to 150 nm CdS on ITO might be an effective range to satisfy a high short circuit current and low defect densities at the CdS/CdTe interface. Finally, a minimum 2 μm thickness for the CdTe on the ultra-thin Schott glass coated by optimum layers can result in the highest short circuit current of 28.69 mA/cm2. This work offers a practical equivalent strategy to be applied for any superstrate solar cells containing TCO and CdS frontal layers.

Electrochromic Behavior of Vanadium Pentoxide Thin Films Prepared by a Sol–Gel Spin Coating Process

Herein, the synthesis of vanadium oxide thin films with high electrochromic coloration efficiency through a simple sol–gel spin coating technique is reported. The structural studies confirm the formation of V2O3V2O5 mixed phase at 250 °C and the pure β‐V2O5 phase at 350 and 450 °C. The decrease in optical bandgap, refractive index, and extinction coefficient improves the transmission ability of the films at higher temperatures. The photoluminescence emission peak observed at 553 nm is due to the recombination of electron–hole pair intrinsic transition from the lowest split‐off V 3d band to the O 2p valence band. The tuning of surface morphology from rod to platelet structure may be due to the higher annealing temperature which assists the disorder movement of the particles. The observed V 2p core levels confirm the existence of V5+ oxidation state with the splitting of 7.2 eV. The electrochromic behavior of vanadium oxide film is detected in 0.5 m LiClO4 in propylene carbonate electrolyte solution. The results show that the film annealed at 450 °C exhibits high coloration efficiency of 110.98 cm2 C−1, good reversibility of 99%, and faster switching speed for bleaching (2.1 s) and coloration (2.4 s) processes.

Effect of solvent volume on the properties of ZnWO4 nanoparticles and their photocatalytic activity for the degradation of cationic dye

In this paper, we report the photocatalytic degradation performance of zinc tungstate (ZnWO4) nanoparticles prepared by co-precipitation technique by the effect of increasing the volume of solvent (30 ml−90 ml). The well defined x-ray diffraction peaks confirmed the formation of pure monoclinic phase zinc tungstate with wolframite structure. The vibrational bands corresponding to W-O bond stretching and bending vibrations in WO6 group are occurred at 714 and 615 cm−1, which indicates the good crystallinity and relatively low concentration of defects in ZnWO4. The photoluminescence emission peak observed at 380 nm region is due to the electronic transition of Zn-WO4. The optical energy band gap decreases (3.19 eV−3.16 eV) as the volume of the solvent increases (30–90 ml) which may be due to the reducing interaction of metal–oxygen orbital. The photocatalytic activity of wolframite ZnWO4 nanoparticles was investigated by the decomposition of methylene blue (MB) dye pollutant under ultra-violet (UV) lamp (254 nm) irradiation at room temperature. The highest dye removal efficiency of 81% was noticed for ZnWO4 nanoparticles synthesized with 30 ml volume of solvent, which may be due to the presence of more active species and nanopores on the surface.

Insights into the composition-structure-property relationship in P2O5[sbnd]CaO[sbnd]Na2O[sbnd]CuO bio-relevant glasses

Copper-containing calcium phosphate glasses possessing antimicrobial properties have attracted attention for biomedical applications in tissue engineering. Yet, composition-structure-property evaluations linking structural, thermal and optical properties with the oxidation states of copper are lacking. In this work, bio-relevant P2O5CaONa2OCuO glasses were prepared by melting with increasing [CuO]/[Na2O] molar ratios (0.1–1.5), and studied by X-ray diffraction (XRD), Fourier transform-infrared (FT-IR) spectroscopy, thermal/dilatometric analysis, optical transmission, X-ray photoelectron spectroscopy (XPS), and photoluminescence (PL) spectroscopy. The XRD analysis confirmed the non-crystalline structure of the glasses. The FT-IR evaluation indicated that increasing the [CuO]/[Na2O] ratio significantly supports the connectivity of the glass network. The thermal characterization revealed a trend of increase in the glass transition and softening temperatures, while the coefficient of thermal expansion decreased with increasing CuO thus harmonizing with a glass strengthening. The optical evaluation showed substantially decreased transmission from the red toward the near infrared region due to d-d transitions in Cu2+ ions. A significant red shift in the glass transmission edge was also exhibited, wherein a decrease in the optical band gap energies with increasing CuO content was indicated by Tauc plot assessment. Further evaluation of the Urbach energies was performed which suggested increased structural disorder for high [CuO]/[Na2O] ratios. While XPS did not support a trend of increasing contents of non-bridging oxygens in the glasses, it indicated copper occurred most significantly as Cu+ besides Cu2+. It is supported that the decrease in optical band gaps and increase in Urbach energies follows the incorporation of copper ions rather than an increase in non-bridging oxygens. PL spectra showed features ascribed to Cu+ merely for the glass with lowest [CuO]/[Na2O] ratio, whereas an emission quenching was indicated for higher CuO content coherent with a Cu+ → Cu2+ energy transfer.

Effect of carbon nano tube in the structural and physical properties of polyvinyl chloride films

Polyvinyl chloride (PVC) films loaded by different concentration of Carbon Nano Tubes (CNT) are prepared through a solution casting method. CNT are characterized using transmission electron microscope (TEM) and x-ray diffractometer (XRD). The analysis of the PVC-CNT films is carried out by using XRD, scanning electron microscope (SEM), and Fourier transform infrared (FTIR) to study the change in the polymer structure. UV–vis spectrophotometer is used to determine the optical parameters depending on the optical absorption data. It is found that, the direct and indirect optical band gap decrease with an increase in CNT nanoparticle content in the PVC matrix. The refractive index, optical dielectric parameters, and optical conductivity of the polymer films are investigated using the optical absorption data. These parameters are enhanced with the increase in the CNT concentration in the PVC matrix. The Wemple-DiDomenico model is used to calculate the optical dispersion parameters (like; oscillator energy, dispersion energy, static refractive index, dipole strength, and static optical dielectric constant). In addition, nonlinear refractive index, linear optical susceptibility, and third-order nonlinear optical susceptibility are investigated.

Fabrication of dye-sensitized solar cells with ZnO nanorods as photoanode and natural dye extract as sensitizer

Highly oriented zinc oxide nanorods (ZnO NRs) have been grown on ITO substrates at various growth times using hydrothermal method. The necessary ZnO seed layers on ITO have been deposited using spray pyrolysis. Both the methods have been successfully applied to prepare efficient ZnO NRs-based photoanodes for DSSCs. FESEM images revealed the vertical growth of ZnO NRs from the substrates with a length and diameter ranges of 1.2–1.5 μm and 80–120 nm, respectively. The XRD and HRTEM results confirmed the hexagonal structure with preferential orientation (c-axis) of ZnO NRs. The high optical transmittance (90%) was observed in the visible region for the ZnO NRs grown for 9 h. A decrease in optical bandgap was noticed with the increase of growth times. The natural dye extract absorbed in to the ZnO NRs exhibited a broad absorption peak in UV–Vis spectra analysis. The power conversion efficiency of DSSCs prepared with ZnO NRs (9 h) as photoanode showed better performance compared to other growth times.

Characterization of optical and radiation shielding behaviors of ferric oxide reinforced bismuth borate glass

This study aimed to investigate the ferric oxide effect on optical and radiation shielding behaviors of bismuth borate glasses. Gamma-ray attenuation competencies of six glass samples along with optical properties were investigated in terms of their utilization suitability as a shield or personal protection equipment in industrial and medical fields. The chemical composition (60-x) B2O3 + 20Bi2O3 + 20Li2O+xFe2O3 with different Fe2O3 concentrations were prepared using the melt-quenching technique. Gamma-ray attenuation competencies of six glass samples along with optical properties were investigated in terms of their utilization suitability in industrial and medical fields. The outcomes of optical investigations indicated that direct optical band gap (Eg direct) decrease from 5.11 eV to 4.82 eV, while for indirect transition (Eg indirect) decrease from 4.62 eV to 3.79 eV, with increasing Fe2O3 concentrations. To determine the radiation shielding performance, mass attenuation coefficients (μ m) of samples were calculated using FLUKA code and XCOM program between 0.015–15 MeV photon energy range. Accordingly, gamma shielding parameters such as mass (MAC) and linear (LAC) attenuation coefficients, half-value layer (HVL), tenth value layer (TVL), mean free path (MFP), effective atomic numbers (Zeff), electron density (Nel), and fast neutron removal cross sections (ΣR) were evaluated for all glass samples. The results showed that increasing Fe2O3 concentration in glass structure increased the MAC and Zeff. The Fe-10 was reported with the lowest HVL values in addition to the highest MAC and Zeff values.