Optical Band Gap Values Research Articles

Enhancement of hole mobility in high-rate reactively sputtered Cu2O thin films induced by laser thermal annealing

In presented work, a reactive high-power impulse magnetron sputtering (r-HiPIMS) was used for high-rate deposition (≈ 170 nm/min) of Cu2O films. Films were deposited on a standard soda-lime glass (SLG) substrate at a temperature of 190 °C. As-deposited films exhibit poor hole mobility in the orders of ≈ 1 cm2/Vs. We have systematically studied the effect of laser thermal annealing (LTA) procedure performed using high-power infrared laser under different laser parameters (number of pulses, length of the pulse). We have found, LTA procedure could significantly enhance the hole mobility (up to 24 cm2/Vs in our case). We have also fitted the results of a temperature-dependent Hall measurement to clarify the mechanism of the reported increase in hole mobility. Moreover, we have discussed the effect of the LTA procedure on microstructure (crystallinity, surface morphology) and on the value of optical band gap.

Fabrication and analysis of ZnO and Al-doped ZnO films using the SILAR technique

In this study, undoped ZnO and Al-doped ZnO thin films were successfully deposited on ITO substrates at various concentrations using the SILAR method. The deposited thin films underwent characterization via SEM/EDS, XRD, and UV-Vis spectroscopy. XRD analysis revealed that the thin films crystallized at the nanoscale, with crystallization quality varying based on the concentration of Al dopant. SEM/EDS analysis indicated a notable influence of Al doping concentration on the morphology of ZnO thin films. UV-Vis analysis highlighted significant differences in both the optical band gap values and transmittance of the thin films depending on the dopant used.

Fabrication of CZTS Thin Film on Flexible Cu-Foil Substrate by Two-Stage Process

In this research, CZTS thin films grown on flexible Cu-foil with varying sulfurization times. Various characterization methods were employed, including X-ray diffraction (XRD), Raman spectroscopy, energy-dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), optical transmission, and photoluminescence (PL) measurements. Distinctive diffraction peaks characteristic of the kesterite CZTS phase were observed in the XRD analysis, occurring around at 2θ= 28.45° (112), 47° (220/204), and 56° (312/116). Additionally, some secondary phases such as Cu2S and SnS were identified. Raman spectroscopy confirmed the presence of the kesterite phase, with a prominent peak detected at approximately ~336 cm-1, attributed to sulfur atom vibrations within the kesterite structure. Apart from CZTS structure, minor peaks suggesting the presence of the Cu2SnS3 (CTS) phase was detected. EDX analysis revealed compositions with Cu-poor content and Zn-rich content across all samples, with slight variations in sulfurization dwell times affecting the chemical composition. SEM imaging at different magnifications showed alterations in surface morphology and grain structures. Films sulfurized for 30 s and 60 s displayed a granular structure morphology, while extending the dwell time to 120 s resulted in a more compact surface morphology. Optical band gap values ranged between 1.57 and 1.60 eV. PL measurements consistently exhibited strong PL emission around 1.25 eV for all samples, attributed to various transitions within the CZTS structure. The absence of observable band-to-band transitions in the PL measurements indicated the presence of intrinsic defect levels and recombination centers within CZTS. Overall, it was demonstrated in this study that CZTS thin films can be produced on flexible Cu-foils with short sulfurization times, thereby expanding the application areas of CZTS thin-film solar cells.

Photocatalytic Activities of Methylene Blue Using ZrO2 Thin Films at Different Annealing Temperatures

Tetragonal ZrO2, synthesized by the sol–gel method and dip-coating technique, was found to be photocatalytically active for the degradation of methylene blue. The ZrO2 thin films were characterized by X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and UV-vis spectroscopy. The photocatalytic degradation of methylene blue was carried out with this material. We identified the tetragonal phase in ZrO2 thin film at different annealing temperatures from 400 °C to 550 °C. The XRD study indicated that the films were monocrystalline in nature with preferred grain orientation along (011) plane and exhibited a tetragonal crystal structure. The crystallite size of the films increased with increasing annealing temperature. FTIR explained the bonding nature and confirmed the formation of the composite. UV-Vis showed the optical absorbance was high in the visible region and the optical band gap value increased with annealing temperature. The photocatalytic experimental results revealed that ZrO2 thin films degraded MB by 20%, 24%, 29%, and 36%, with annealing temperatures of 400 °C at 550 °C for 10 h, respectively. Our results provide useful insights into the development of photocatalytic materials and degradation of methylene blue.

Structural, optical and theoretical studies of 2,4-dichlorobenzoic acid benzamide in nonlinear optical applications using Z-scan technique

New organic 2,4-dichlorobenzoic acid benzamide co-crystal (DCBB) was successfully grown using slow evaporation solution growth technique. The formation of new DCBBco-crystals was taken and their structure and crystallinity were analyzed by single crystal and powder X-ray diffraction analyses. It shows that DCBB material in monoclinic structure with centrosymmetric space group of P21/c. The different vibrations, chemical bonding and chemical configuration of the co-crystal was studied through FTIR, Raman and 1H NMR spectroscopy. Optical transmittance is the basic requirement for the nonlinear optical application with a lower cutoff wavelength of about 320 nm as well as optical band gap value Eg is 3.84 eV. Photoluminescence spectrum showing two emission peaks of 403 and 550 nm by means of an excitation wavelength of 290 nm. The compound's thermal stability was up to 125 °C was analyzed by the thermal analysis. Vickers's micro hardness test was used for evaluating mechanical properties of DCBB, and the results showed that the material was classified as soft category (n = 2.54). Nonlinear optical characteristics of the sample under pulsed laser stimulation by Q-switched Nd:YAG laser with 532 nm wavelength. The presence of reverse saturable absorption peak exhibits 2-photon absorption process was confirmed by varying its intensity shows saturation intensity IS), nonlinear absorption coefficient (β) under pulse laser excitation. The optical limiting threshold determined by three different intensities were found to be 3.02×1012 (W/m2), 2.85×1012 (W/m2) and 1.44×1012 (W/m2) respectively. Theoretical investigations like density functional theory using B3LYP to calculate as well as determining non-linear optical characteristics of the DCBB complex.

Production and Characterization of Electrodeposited Cadmium Sulfide Semiconductor Films with Different Boron Content

AbstractIn this study, Cadmium Sulfide (CdS) semiconductor films are electrodeposited on Indium Tin Oxide (ITO) substrates at 80 °C base temperature for different boric acid (H3BO3) ratios. The effect of boric acid on these films is investigated. For this, first of all, the structural change of the films is examined. Among the films obtained with different boric acid ratios, the optimum film is achieved with 0.06 m boric acid doped. From the basic absorption spectra (αhʋ) of the obtained CdS:B films, the variation of hʋ is drawn and it is determined that the CdS:B semiconductor films has a direct band transition. From the basic absorption spectra of the obtained CdS:B films, it is observed that the CdS:B semiconductor films has a direct band transition. In addition, the optical energy bandgap values obtained are in agreement with the values in the available literatures. The results of the structural, optical, and morphological properties of the films produced in this study indicate that among the selected additive ratios, 1% boric acid gives the best and optimum deposition condition. The thin films obtained are also found to be useful as absorber layers in photovoltaic solar cells.

Linear and non-linear optical and dielectric properties of transition metals complexes films derived from Azo-Schiff base for photovoltaic applications

A novel azo-Schiff base, which incorporates a heterocyclic triazole nucleus known as 1H-1,2,4-triazol-5-yl)imino)methyl)-5-((2-nitrophenyl)diazenyl)phenol (H2ASB, 1), was formulated and synthesized. Furthermore, a series of Cu2+ complexes, derived from this azo-Schiff base, were prepared by a simple method with a molar ratio of 1 M Cu2+ to 1 M H2ASB. The synthesized compounds were thoroughly characterized using alternative analytical and spectral techniques. The obtained results confirmed that H2ASB bonded with the Cu2+ ions in a uni-negative/neutral bidentate manner, via the phenolic hydroxyl oxygen and azomethine nitrogen atom, thereby resulting in tetrahedral or octahedral geometries. Additionally, theoretical studies employing DFT/B3LYP/LanL2DZ were conducted, which included the assessment of global reactivity descriptors, dipole moment, molecular electrostatic potential image (MEP), optimized geometry, and the LUMO-HOMO energy gap to support the geometrical structure of the synthesized compounds. On the other side, the optical constants of H2ASB and its complexes have been studied over 300–1500 nm spectral range. The optical band gap (Eg) values of the present film's changes from 1.92 eV for H2ASB to 1.45 eV for CuHASB(5) film whereas the static index of refraction (n) takes a different behavior. The obtained values of n and Eg are the same as those recorded for many semiconductor materials. This means that, compared to the cost and ease of preparation, these films under study could replace many other semiconductors, such as CdTe with (Eg = 1.5 eV) which is the same value of CuHASB(4) film. With the help of n and extinction coefficient (k) values, the dielectric and non-linear optical parameters have been estimated and well discussed. Finally, the sheet resistance (Rs) and thermal emissivity (εth) changes due to the incident photon energy have been investigated. It was observed that, the change of Rs and εth with E is opposite to the change of other parameters such as the absorbance and optical conductivity.

Facile synthesis of Ag2ZrO3 nanocrystals with highly enhanced visible-light photocatalytic activity

Abstract This paper describes the synthesis of Ag2ZrO3 nanocrystals using coprecipitation and microwave-assisted hydrothermal methods. These nanocrystals were characterized by means of X-ray diffraction, micro-Raman spectroscopy, Fourier transform infrared absorption spectroscopy, field emission scanning electron microscopy, and UV–Visible spectroscopy, and their photocatalytic performance for methylene blue degradation under visible-light irradiation has been tested. The X-ray diffraction, micro-Raman spectroscopy, Fourier transform infrared absorption spectroscopy analyses indicate that the Ag2ZrO3 nanocrystals have good crystallinity and no secondary phases. The UV–Visible spectroscopy results showed a variation in the optical band gap values (2.71–2.97 eV) with increasing temperature, which indicates the possible presence of defects in the crystal lattice at a medium range. Field emission scanning electron microscopy images revealed that the nanocrystals have uneven spherical shapes and average particle size around 50–70 nm. The good photocatalytic efficiency can be attributed to defects in the silver zirconate structure capable of forming the active adsorption sites. Finally, we discuss a photocatalytic mechanism to understand the photocatalytic process in cationic dye (methylene blue) degradation in aqueous solution.

Structural, vibrational, and optical studies of newly synthesized Yavapaiite-type phases BaSb2/3X1/3(PO4)2 (X = Mn, Co, Cu, Zn)

The synthesis and structural characterization of four newly synthesized phosphates, BaSb2/3X1/3(PO4)2 phases where X represents Mn, Co, Cu, and Zn, are presented here for the first time. These BaSb2/3X1/3(PO4)2 phases, denoted as [BaSbMn], [BaSbCo], [BaSbCu], and [BaSbZn], were prepared by a solid-state reaction at 900 °C in air atmosphere. The crystal structures of these [BaSbX] materials were investigated using Rietveld analysis based on conventional X-ray powder diffraction. The structural analysis revealed that all four compounds are isostructural, exhibiting the Yavapaiite-type structure with a monoclinic C2/m space group. Raman and infrared spectroscopy were employed to elucidate the bonding characteristics within the [BaSbX] phases. UV–vis-NIR spectroscopy provided insights into the electronic properties of the compounds, revealing charge transfer and d-d transitions in Mn2+, Co2+, and Cu2+ ions. In contrast, Zn2+ exhibited full d orbitals. The absorption spectra revealed UV bands indicative of charge transfer, with optical bandgap values spanning from 3.8 eV to 4.6 eV. This range signifies a distinctive semiconducting property inherent in the synthesized materials. Analysis of the Urbach tails revealed the presence of localized states, with lower values indicating higher crystallinity, giving valuable insights into the electronic behavior of the compounds.

Chemical bath deposited CdTe thin film: Optical, electrical, and photoresponse aspects

Owning a narrow bandgap, remarkable optical and electrical properties with notable stability has made cadmium telluride (CdTe) an immensely vital semiconductor to develop cutting-edge optoelectronics. Taking these properties in to account, CdTe thin film is deposited employing the chemical bath deposition (CBD) technique. The X-ray diffraction analysis of the as-deposited thin film unveiled the composite crystalline structure, incorporating cubic, hexagonal, and tetragonal phases. The energy dispersive X-ray analysis and X-ray photoelectron spectroscopy ascertained the chemical composition of CdTe thin film. Distinctive Raman peaks are detected at 141 and 167 cm−1, signifying the presence of Cd-Te bond in the deposited thin film. The comprehensive evaluation of scanning electron micrographs emphasized the firm adhesion of the film to the substrate and displayed a uniform overlay of microstructures resembling rods. The observations from atomic force microscopy unveiled uniform grain structure with topographical features of hills and valleys. The UV-Visible spectroscopic examination elucidated that the as-deposited thin films exhibits a direct optical bandgap value of 1⋅59 eV. Temperature-dependent analysis of d.c. electrical resistivity exhibited a descending pattern, substantiating thin film's semiconducting attributes. The investigation into the photoresponse attributes of the thin film is accomplished by subjecting it to a polychromatic light, green and red monochromatic light source with an intensity of 50 mW/cm² employing three different biasing voltages. The thin film demonstrated maximum photocurrent for red light source than polychromatic and green light with maximum responsivity of 59⋅4 μA/W and detectivity of 17⋅7 × 106 Jones. These findings provide valuable insights on the photoresponse behavior of CBD deposited CdTe thin film in its as-deposited form.

Optical characterization and dispersion analyses of plasma polymerized methyl acrylate thin films

This work reports the structural characteristics, surface morphology, linear and nonlinear optical properties of 110 to 225 nm thick plasma polymerized methyl acrylate (PPMA) thin films. X-ray diffraction analyses confirm the amorphous nature of the films. Field emission scanning electron micrographs of the films display cluster-based surface morphology. Attenuated total reflectance Fourier transform infrared spectroscopy confirms the chemical structural changes in the films. The optical properties were studied based on the absorbance, transmittance, and reflectance spectra measured by an ultraviolet–visible spectrophotometer within the wavelength ranges from 200 to 800 nm. The direct optical band gap and Urbach values are increased from 3.66 to 3.83 eV and 0.28 to 0.45 eV, respectively with increasing film thickness. The extinction coefficient and refractive index were evaluated, and discussed a correlation between the refractive index and the optical bandgap. The real and imaginary dielectric constants, volume/surface energy loss functions and skin depth were deduced. The oscillator energies and parameters were analyzed using the concept of Wemple-DiDomenico and Sellmeier models, respectively for a single oscillator. Static linear refractive index for the studied films exhibits normal dispersion behavior with film thicknesses and satisfied Moss, Ravindra-Gupta, and Herve-Vandamme rules. The linear susceptibility, third-order nonlinear susceptibility and the non-linear refractive index are considerably reduced from 0.20, 29.5 × 10−14 esu, and 5.89 × 10−12 esu with increasing optical band gap energies. The outcomes from the analyses of PPMA demonstrated their potential for usage in electronic, optoelectronic, and non-linear device applications.

Synthesis, optical, and spectroscopic studies of bismuth boro-tellurite glass system containing BaO and V2O5

A melt quenching technique was used for the preparation of xBaO–(30-x)TeO2–35Bi2O3–33B2O3–2V2O5 (5 ≤ x ≤ 25 mol%) glasses. The structural modifications are studied by X-ray diffraction, DSC, optical, infrared spectroscopy, and Raman as a function of BaO mol%. The progressive incorporation of BaO mol% in the BTBiBV glasses decreases the optical band gap values as the number of free electrons increases with the creation of additional NBOs. The FTIR spectra of the prepared glasses consist of BO3 trigonal and BO4 tetrahedral units while TeO2 changes to TeO3 andTeO4 structural units. The Raman spectra shows that the replacement of BaO with TeO2 decreases the concentration of Te–O–Te linkages within the volume of host glass, which increases the concentration of Ba–O–Te linkages along with BO3 units. Due to this, the overall glass formers connectivity decreases which intern to the creation of NBOs. Moreover, the research highlighted that BTBiBV-5 glasses have exceptional optical properties making them promising materials for photonics, optoelectronics, and optical communication device applications.

Control of NLO and photocatalysis properties based on the use of Sn-doped ZnO thin films for optoelectronics applications

Thin films of zinc oxide (ZnO) have unique properties that make them suitable for various applications. In this study, we used a spray pyrolysis process to develop undoped ZnO and ZnO doped with Sn thin films on a glass substrate. We aimed to investigate the effect of Sn concentration on the optical, nonlinear optical, and structural properties of ZnO:Sn thin films. X-ray diffraction analysis revealed that all the deposited ZnO thin films exhibit polycrystalline hexagonal structures well-oriented along the c-axis. The obtained films were transparent in the visible range, with a transmittance between 70% and 80%. The optical energy bandgap values for the films varied from 3.16 eV to 3.29 eV. We also determined the second- and third-order nonlinear susceptibilities, which decreased with increasing Sn concentration. We investigated the photocatalytic activity of the ZnO-doped Sn thin films using methylene blue dye under visible light. Sn doping enhanced the photocatalytic activity of ZnO thin films, with constant rate values of 0.00046 and 0.00074 min[Formula: see text] for ZnO and ZnO:Sn thin films, respectively.

New insights into optical properties, and applications of Zr-doped BaTiO3

The present work scrutinizes a few uses of barium titanate BaTi1–xZrxO3 (0.0 ≤ x ≤ 0.3) nanoparticles, which are an innovative and highly promising material for a variety of applications, including optical applications; and waste water treatment. To estimate the quality of a synthesized powder relative to an already existing commercial powder, the samples were prepared using cheaper raw materials and simpler, faster procedures than those reported in other literature at lower annealing durations and temperatures. The prepared samples were characterized by field emission scanning electron microscopy (FESEM), and Raman spectroscopy, which confirmed the coarse nature of the samples and the system's tetragonality. Furthermore, UV–visible absorbance of all compositions was studied. It has been determined that optical transition is directly allowed after extensive research, and the optical band gap (Eg) values increase with increasing (Zr4+) ion concentration. The derivation of absorption spectrum fitting (DASF) technique was used to support the type of transition and calculate the value of the coefficient of electronic transition (n). Samples can perform overall water splitting and CO2 reduction processes. The Langmuir and Freundlich isotherms were used to comprehend the procedure of adsorption on the investigated samples. The BaTi0.8Zr0.2O3 has been used to successfully remove 99.9% of heavy metals (Cr6+) from wastewater. The obtained results provide new insights into the control of the structure, and optical behaviors in BaTi1–xZrxO3.

Shielding parameters and optical stability of sodium alumino-borate glasses against gamma rays by iron oxide additives

The development of various industries and technologies necessitates a greater utilization of ionizing radiation, such as gamma rays. Herein, we investigate the shielding parameters and the stability of the optical parameters of sodium alumino-borate glasses against gamma rays by different iron oxide (Fe2O3) additives. We found that the Fe2O3 additives improved the shielding parameters. Moreover, the influence of various doses of γ rays (50, 100, and 150 kGy) on the optical characteristics of the performed glasses was studied. For example, the influence of gamma doses on the optical absorbance (A), optical band gap (Eg), Urbach energy (EU), refractive index (no), electronegativity (X), electron polarizability (αo), and nonlinear refractive index (n2). The optical absorbance of all glass samples increased, particularly in the visible range, with further irradiation.Furthermore, the reduced optical band gap and Urbach energy values grow as the gamma irradiation increases, which are attributed to the increased number of donor centres. Conversely, an investigation was conducted on the ability of the material to protect against radiation. We found that the Fe2O3 additives improved the shielding parameters. Furthermore, the half-value layer results of the glassy samples in question were compared to those of conventional radiation shielding materials and glasses. Therefore, the glass samples work better at blocking radiation than conventional window glass when employed for radiation shielding purposes.

Tuning the optical, and dielectric properties of PVC/PEO/NiMoO4/MWCNTs/x wt %PANI blended polymers for optoelectronic applications

Nanoparticles of nickel molybdate (NiMoO4) have attracted significant interest for their application as electrode materials. Here, new hybrid blended polymers, poly (vinyl chloride)/polyethylene oxide/nickel molybdate/multi-walled carbon nanotubes/polyaniline (PVC/PEO/NiMoO4/MWCNTs/x wt %PANI) were prepared. Several techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), diffused reflectance, fluorescence and LCR meter were used to investigate the impact of the different fillers on the structure, electrical and optical features of the PVC/PEO blend. The structures of NiMoO4 and different blends were explored using XRD technique. The linear and nonlinear optical properties and the emitted colors of host blend are found to be affected by NiMoO4, MWCNTs and different amounts of PANI fillers. The T values of PVC/PEO were reduced as it loaded with NiMoO4/MWCNTs/x wt %PANI and it reached its minimum value (21–37% in the visible range) in NiMoO4/MWCNTs/x 0.4 %PANI blend. The minimum direct and indirect optical band gap values (4.09, 4.9) eV and (1.92, 3.47, 3.94) eV, respectively, were obtained as the amount of PANI became 0.4 wt % in the doped blend. The doped PVC/PEO blend with NiMoO4 has the highest refractive index value (2.11) at 600 nm. The highest nonlinear optical parameters were acquired exclusively in the visible spectrum when PVC/PEO was doped with NiMoO4.The maximum energy density value (6.03 × 10−3 J/m3) was obtained when the host blend loaded with NiMoO4/MWCNTs. Thus, PVC/PEO/NiMoO4/MWCNTs/x wt %PANI blends are recognized as a good prospect for UV blocking, solar cell, optoelectronic, nonlinear optical devices and energy storage innovation.

Enhancement in photophysical properties of octacoordinated Dy(III) complexes via energy transfer from photosensitizing ligands

In this study, β-diketone (1,1,1-trifluoroacetylacetone, tfaa) based mononuclear anhydrous octacoordinated dysprosium complexes i.e. [Dy(tfaa)3(TOPO)2] (D1), [Dy(tfaa)3(phen)] (D2), [Dy(tfaa)3(NeoC)] (D3) and [Dy(tfaa)3(BathoC)] (D4) were synthesized using four different neutral ligands. The effect of different sensitizers on Dy(III) ion is analyzed using various spectroscopic and analytical techniques. The composition and bonding were examined by elemental analysis, infrared spectroscopy, NMR spectroscopy and thermal analysis (TGA). The luminescent characteristics of the synthesized complexes were further investigated. The complexes, when exposed to UV light, displayed characteristic emissions of the central Dy(III) ion. The photoluminescence spectra indicated the strongest emission intensity of D3 complex. The hyper-intense transition in all complexes is sensitive to the metal ion environment. The semiconducting nature of complexes was confirmed by optical and electronic band gap values obtained from absorption spectroscopy and cyclic voltammetric analysis, respectively. The neutral ligands (TOPO, phen and its derivatives) along with tfaa, are found to be good sensitizers for trivalent dysprosium ion. All the characteristic features of these prepared complexes show their potential applications in the fabrication of OLEDs.

Preparation, structural characterization, optical, photoluminescence, AC electrical conductivity and broadband dielectric properties of WO3 reinforced PEG/CS blend for futuristic optoelectronic and energy storage devices

Polymer nanocomposites (PNCs) composed of biopolymers and metallic oxides are important classes of materials. In addition to the environmental and economic considerations, these materials became the best candidates for various industrial fields. In the current study, solution cast procedure is used to prepare polymer nanocomposites (PNCs) based on polyethylene glycol (PEG)/chitosan (CS) blend and varying concentrations of tungsten trioxide nanoparticles (WO3 NPs), as a nanofiller. TEM micrograph shows that WO3 NPs have particle sizes of 5–32 nm their shapes are cubic and spherical. The XRD results reveal the semicrystalline of PEG/CS blend through showing three distinct diffraction peaks at 2θ = 7.42°, 19.47° and 23.62° and the degree of crystallinity is decreased after the incorporation of WO3 NPs due to the formation of polymer-nanoparticle interactions as indicated by FTIR spectra. The values of optical energy bandgap (direct and indirect) reduce while the Urbach energy increases with raising the concentration of WO3 NPs in the PEG/CS matrix. The PEG/CS-WO3 films' PL spectra show a photoemission peak at about 387 nm, where this peak loses intensity and becomes broader due to the induced defects and increase of disordering within the nanocomposite films. Additionally, the results of the dielectric investigation show an increase in the dielectric constant, dielectric loss, and AC electrical conductivity, which may be a sign of an increase of charge carriers and the content of amorphous regions that assists the movement of charge carriers. The DC electrical conductivity and conduction mechanism are also reported. Argand plot shows a half semicircle implying the Debye-type relaxation mechanism. The experimental results suggest the use of PEG/CS-WO3 nanocomposites as a possible contender for futuristic energy storage and optoelectronic applications.

Synthesis, characterization and properties of Cr-doped ZnO nanoparticles via a facile solvothermal route

Cr-doped ZnO ([Formula: see text]–0.08) nanoparticles are synthesized using the microwave solvothermal irradiation technique. The final product is calcinated at 450∘C and the nanostructure of the material is investigated using various techniques. In structural studies, XRD analysis shows that the hexagonal wurtzite structure of ZnO is present in the standard JCPDS card. FESEM spectrum reveals the hexagonal shape of the synthesized samples and EDS provides information on the qualitative composition of the nanoparticles. Optical absorbance images show exciton peaks in the UV region, which can be attributed to Cr incorporation into the ZnO lattice, and the optical energy bandgap values are calculated using the tauc plot method. Photoluminescence (PL) emission spectra are measured using PL spectroscopy. Interestingly, vibrating sample magnetometry (VSM) reveals enhancements in the magnetic properties in M–H loops and it is widely used for biological applications like antibacterial activity.

Sonochemical synthesis of SnS and SnS2 quantum dots from aqueous solutions, and their photo- and sonocatalytic activity

Our study reports the ultrasound-assisted synthesis of SnS and SnS2 in the form of nanoparticles using aqueous solutions of respective tin chloride and thioacetamide varying sonication time. The presence of both compounds is confirmed by powder X-ray diffraction, energy-dispersive X-ray spectroscopy, as well as Raman and FT-IR spectroscopic techniques. The existence of nanoparticles is proven by powder X-ray diffraction investigation and by high resolution transmission electron microscopy observations. The size of nanocrystallites are in the range of 3–8 nm and 30 50 nm for SnS, and 1.5–10 nm for SnS2. X-ray photoelectron spectroscopy measurements, used to investigate the chemical state of tin and sulphur atoms on the surface of nanoparticles, reveal that they are typically covered with tin on the same oxidation degree as respective bulk compound. Values of optical bandgaps of synthesized nanoparticles, according to the Tauc method, were 2.31, 1.47 and 1.05 eV for SnS (60, 90 and 120 min long synthesis, respectively), and 2.81, 2.78 and 2.70 eV for SnS2 (60, 90 and 120 min long synthesis, respectively). Obtained nanoparticles were utilized as photo- and sonocatalysts in the process of degradation of model azo-dye molecules by UV-C light or ultrasound. Quantum dots of SnS2 obtained under sonication lasting 120 min were the best photocatalyst (66.9 % color removal), while quantum dots of SnS obtained under similar sonication time were the best sonocatalyst (85.2 % color removal).