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Graphene nanoplatelets (GNPs) offer excellent support for a diverse array of composite applications. Herein, Co0.5Mg0.5Fe1.8La0.2O4 (CMFL) and its composites were prepared by the sol–gel autocombustion method. X‐ray diffraction confirmed the formation of a single‐phase structure, with both the average crystallite size (34.33–46.30 nm) and the lattice constant (8.292–8.411 Å) increasing with GNP insertion. The presence of graphene in the nanocomposites was confirmed by Raman spectroscopy, which revealed a D band at 1376.38 cm−1. The Fourier transform infrared spectra indicated the existence of absorption bands corresponding to tetrahedral (534.46–525.94 cm−1) and octahedral (456.62–454.95 cm−1) structures. The optical bandgap energy (Eg) varied when the compositions of the samples were changed, with the lowest value of Eg being 2.58 eV for CMFL/2.5 wt.% GNPs. The DC electrical resistivity increased from 6.73 × 104 to 1.07 × 106 Ω cm, indicating that the composite materials might be appropriate for use in transformers and telecommunications devices. With increasing frequency, the dielectric constant and loss decreased, whereas the AC conductivity improved. The Cole–Cole behavior showed that the conduction mechanism had non‐Debye relaxation characteristics. The saturation magnetization increased from 25.86 to 42.75 emu/g for the synthesized samples, and the coercivity demonstrated a variable trend. [ABSTRACT FROM AUTHOR]

AbstractVolatile organic compounds (VOCs) are hazardous chemicals that significantly threaten public health, making their remediation an increasingly pressing concern. Among the various solutions proposed, the use of TiO2 photocatalysts has garnered attention because of their practicality, cost-effectiveness, high catalytic activity, and human-friendly nature. This study discussed the potential of Wolfram (W)-doped TiO2 catalyst in enhancing VOC degradation under UV light irradiation and used xylene as the target VOC. The nanostructured W-doped TiO2 materials were fabricated without surfactants or post-reaction calcination at a low temperature for 10 h, yielding promising results. We carefully investigated these nanomaterials’ characterization using microscopic and spectroscopic techniques such as XRD, TEM, SEM, EDS, XRF, EIS, and XPS. The XPS analysis revealed W-O-Ti linkages and improved charge separation, while EIS showed enhanced conductivity and reduced charge transfer resistance, with 1.5 mol% W achieving optimal performance. These results evaluate the successful synthesis of W-doped TiO2, which can be applied to VOC treatment. Notably, the photocatalytic degradation of xylene gas reached 99.77% within 10 min of UV illumination. This result demonstrates the outstanding properties of this catalyst as a promising solution for VOCs pollution control. [ABSTRACT FROM AUTHOR]

Self-assembled bicontinuous NiO:SnO 2 films are proposed for enhanced photoelectrochemical hydrogen production efficiency due to their high interface-to-volume ratio and three-dimensional interconnectivity. The X-ray diffraction confirms the superior crystallinity of the bicontinuous NiO:SnO 2 films. Bicontinuous NiO:SnO 2 films reveal a heterostructure of mixed NiO and SnO 2 phases, where the NiO phase exhibits the distribution of small grains, whereas the SnO 2 phase exhibits large agglomerates of SnO 2 crystals embedded in the NiO structure. The bicontinuous NiO:SnO 2 films exhibit lower bandgap energy and higher electrical conductivity compared to pure NiO and pure SnO 2 films. The photoresponsivity of the bicontinuous oxide films is higher than pure NiO and pure SnO 2 films. These results imply the presence of strong charge interactions at the three-dimensional interfaces in bicontinuous NiO:SnO 2 films. The hydrogen revolution reaction analysis confirms that the bicontinuous NiO:SnO 2 films exhibit higher photoelectrocatalyst hydrogen production activity compared to pure NiO and pure SnO 2 films. [ABSTRACT FROM AUTHOR]

We aim to analyze the influence of 5CBLC content on the structural, optical, and dielectric properties of the PVA-PVP blend polymer. The absence of additional peaks in the XRD patterns after doping strengthens the argument for complete dissociation and homogeneous complexation of 5CBLC molecules within the blend polymer matrix. The dopant atoms are no longer arranged in a separate crystalline structure but are uniformly distributed throughout the polymer, leading to no distinct peaks in the XRD pattern. Changes in the wavelengths of maximum absorption indicate changes in the energy required to excite electrons. If the peaks shift towards longer wavelengths (red shift), it suggests a decrease in the energy gap between orbitals, potentially due to increased conjugation caused by 5CBLC. The 0.05 ml of doped PVA-PVP@5CBLC PBFs readily absorbs light at wavelengths below 824 nm. A 5CBLC molecule's energy level may allow it to absorb photons with energies below 824 nm. As 5CBLC scatter and absorb light, there is a decrease in normalizing power with 5CBLC amounts. As the amount of 5CBLC increases, it removes some light from the incident beam through both scattering and absorption. This reduces the amount of light available for further scattering by the particles of interest in the experiment. As both the imaginary and real parts of the impedance decrease, the 5CBLC amounts facilitated a more resistive and less reactive matrix for the PVA-PVP blend. The ESC and EPC significantly decrease with increasing frequency for both the pure PVA-PVP PBF and the PVA-PVP@5CBLC PBFs in various 5CBLC amounts. Results suggest that combining 5CBLC with PVA-PVP creates a material with properties that make it well-suited for applications in optoelectronics. [ABSTRACT FROM AUTHOR]

This 5th annual “Emerging PV Report” highlights the latest advancements in the performance of emerging photovoltaic (e‐PV) devices across various e‐PV research areas, as documented in peer‐reviewed articles published since August 2023. Updated graphs, tables, and analyses are provided, showcasing several key performance parameters, including the power conversion efficiency, open‐circuit voltage, short‐circuit current, fill factor, light utilization efficiency, and stability test energy yield. These parameters are presented as functions of the photovoltaic bandgap energy and average visible transmittance for each technology and application and are contextualized using benchmarks such as the detailed balance efficiency limit. [ABSTRACT FROM AUTHOR]

The optical diffuse reflectance data of a semiconductor material is usually converted into the Kubelka–Munk function before proceeding to process the conventional Tauc's plot from which optical bandgap energy can be determined. Firstly, it is conventional/ customary to convert the percentage reflectance ( (%)) data, which is obtained from UV-vis measurement into an equivalent reflectance () that range between 0 and 1 before processing the Tauc's plot. Secondly, the Kubelka–Munk function is usually multiplied by the incident photon energy, , to produce an all-elements/ comprehensive Tauc's plot. Literature is scarce to convincingly demonstrate that a correct bandgap value can, alternatively be obtained from the Tauc's plot that is derived directly from the ( (%) data without having to convert to . Also, publication is rarely available to demonstrate that a proper bandgap value can be determined without having to multiply the Kubelka–Munk function by the term . The present investigation shows diminutive differences in the bandgap values estimated from the (%)-based Tauc's plots and the equivalent -based Tauc's plots. This suggests that either of the methods can be employed for a precise bandgap estimate. A comparison between the magnitudes of the bandgap energies determined from the comprehensive Tauc's plot and when the Kubelka–Munk function is not multiplied by reveals insignificant differences in the estimated values. This suggests that either of the two methods can be employed to obtain a reliable bandgap for direct and indirect optical gap semiconductors. [ABSTRACT FROM AUTHOR]

For the first time, the magnetic and optical (bandgap) properties of co‐doped Mg/Dy, Al/Dy, and Mn/Nd SrFe12O19$\left(\text{SrFe}\right)_{12} \left(\text{O}\right)_{19}$ (SFO) at Sr and Fe sites are investigated using a microscopic model and the Green's function theory. It is shown that the co‐doping at both Sr and Fe sites can change the behavior of the magnetization which decreases by transition metal or nonmagnetic ion doping at the Fe site (with doping ions larger than the host Fe ions), but by additive co‐doping at the Sr site with rare‐earth ion (which ionic radius is smaller than that of Sr) the magnetization increases with increasing the co‐doping concentration. The bandgap energy decreases in the co‐doped SFO. The mechanism of this co‐doping effect is explained on microscopic level. It is due to the changes of the spin‐exchange interaction constants at the doped sites caused by the appearance of different strain by the doping with two ions. The theoretical results are compared with the existing experimental data and are in good qualitative agreement. [ABSTRACT FROM AUTHOR]

Pb‐free perovskites are novel compounds that are currently being studied, essentially for their photovoltaic applications. In this article, the hybrid organic–inorganic perovskite for photovoltaic applications is studied. In fact, the structural and electronic properties of the perovskite FABI3 (B = Sn, Ge, or Pb and FA = formamidinium: CH(NH2)2) applying the density functional theory method executed in the Quantum Espresso framework are studied and discussed. The band structures of these perovskites have been presented; it is shown that these perovskites have a semiconductor nature, with a bandgap value of 1.36 eV for FASnI3, 1.72 eV for FAGeI3, and 1.61 eV for FAPbI3. Also, the density of states and partial density of states have been presented and discussed for each of these materials. Indeed, the structural properties of these perovskites are investigated and demonstrated that the optimized value of the lattice parameter is 6.35 Å for the FASnI3, while for the FAGeI3, this value is 6.3 Å and 6.5 Å for FAPbI3. Moreover, the impact of the lattice parameter on the bandgap value of FABI3 (B = Sn, Ge, or Pb) has been investigated, and it has been demonstrated that as the lattice parameter increases, the bandgap increases. The results of this work can be utilized as a guideline for the development of new efficient, lead‐free perovskite devices, including tandem solar cells. [ABSTRACT FROM AUTHOR]

Nanostructured ZnS films of various molar concentrations have been deposited using chemical bath deposition (CBD) method on glass substrates in the matrix of polyvinyl alcohol (PVA). Structural analysis of the samples with the help of X-ray diffraction (XRD) shows that the films are of cubic phase structure and diffraction peaks shift toward higher diffraction angle with the increase of molar concentration. Crystallite size is obtained using Scherrer's formula, Williamson–Hall (WH) plot as well as size–strain plot (SSP), and reveals decrease in size with increasing molar concentration. Surface morphology and surface texture of the samples are observed with the help of atomic force microscopy (AFM) and high-resolution transmission electron microcopy (HRTEM) which exhibit the roughly spherical shape of the particles as well as formation of cluster by a large number of ZnS nanoparticles. Observation from selected area electron diffraction (SAED) pattern also confirms the cubic phase of nanostructured ZnS samples. Surface topographic study using scanning electron microscopy (SEM) also shows particle agglomeration forming nanoclusters and energy-dispersive X-ray spectroscopy observation reveals that the films are composed of zinc and sulfur. With the increase of molar concentration, the optical bandgap energy increases whereas the refractive index as well as dielectric constant decrease, and in comparison to ZnS bulk counterpart, the samples are found to be blue-shifted. Samples exhibit blue emission photoluminescence (PL) band and second-order Raman scattering. Fourier-transform infrared (FTIR) technique is utilized to detect the presence of stabilizing agent. [ABSTRACT FROM AUTHOR]

In this study, the sol-gel synthesis technique was harnessed to craft nanocomposites of (1-x)La 0.7 Sr 0.3 MnO 3 -(x)BTO with x values of 0.4, 0.6, and 0.8. The attributes of these meticulously engineered materials were exhaustively explored using a diverse suite of characterization methods. X-ray diffraction analysis irrefutably confirmed the phase purity of the perovskite structure, emphasizing the synthesis's precision. Furthermore, Diffuse Reflectance Spectroscopy shed light on the optical properties of the nanocomposites, revealing a significant shift in bandgap energy that correlated directly with the BTO concentration. Specifically, an increment in BTO concentration resulted in a systematic expansion of the bandgap from 1.51 eV to 1.44 eV. For an in-depth analysis of the magnetic characteristics of the composites, Vibrating Sample Magnetometry was utilized. The magnetic analysis identified a conspicuous reduction in saturation magnetization, highlighting the complex interplay between the composite components at the nanoscale. Additionally, the dielectric properties were rigorously investigated through dielectric measurements, which unveiled a notable increase in the dielectric constant, accompanied by the emergence of novel relaxation behaviors. This finding indicates that adjusting the BTO content within the nanocomposites not only modifies their dielectric properties but also provides a method for fine-tuning their functional performance. [ABSTRACT FROM AUTHOR]

We report the experimental observations of the physical properties enhancement for the (Ni-Co)-doped ZnO films under a photodoping mechanism by UV irradiation. The elemental, structural, and morphological properties confirm that the photodoping mechanism in the (Ni-Co)-doped ZnO films is more successful than the traditional doping mechanism. The doping mechanism of the transparent conducting oxides under UV irradiation generates oxygen vacancies near the metal atoms, reducing the valency of metal ions while leaving dopant ions intact in the films. Therefore, the dopant ions occupy metal sites in the transparent conducting oxides, which enhances the physical properties of the doped transparent conducting oxides. Additionally, the effect of the photodoping mechanism on the bandgap energy, electrical conductivity, and photoconductivity is higher than the effect of the traditional doping mechanism. Finally, we can conclude that the physical properties of the Ni-, Co-, and (Ni-Co)-doped ZnO films are enhanced by using the photodoped method compared to those of the traditional doping method. Therefore, we suggest using the photodoping mechanism in the doped transparent conducting oxide film instead of the traditional doping mechanism. [ABSTRACT FROM AUTHOR]

In this study, we use electrochemical deposition on FTO to grow BaTiS thin films. By varying the temperature of the precursors, we conducted thorough growth studies to understand how these process parameters affected the structure of BaTiS films. The diffraction peaks in the XRD pattern match the cubic barium sulfide structural phase. The observed peaks, 39.994 ° and 65.742 ° at 35 °C; 39.982 ° and 65.717 ° at 45 °C, and 39.995 °, 63.920 °, and 65.856 ° at 55 °C. The film deposited at 55 °C had a surface morphology with uniformly distributed spherical-shaped particles that formed agglomerations. The film's surface was smooth, providing a clearer look at the grain boundaries, suggesting a polycrystalline composition. The films deposited at temperatures of 35 °C, 40 °C, 45 °C, 50 °C, and 55 °C yielded energy band gaps of 2.98 eV, 2.90 eV, 2.69 eV, 2.68 eV, and 2.30 eV, respectively. The result showed that the films' energy band gap decreased as the deposition temperature increased. The varied energy bandgap of the films confirmed the effects of deposition temperature on the films.

High-quality thin films of p-type CuFe 2 O 4 photocathode were prepared for the first time on FTO-coated glass substrates by a novel nonaqueous solution using spray pyrolysis method. The films' critical physical and photophysical properties, including morphology, optical properties, carrier transport properties, band position, and photoelectrochemical (PEC) characteristics, were analyzed and estimated. The feasibility of PEC water splitting was systematically evaluated. The prepared reddish-brown CuFe 2 O 4 film exhibits a compact and uniform morphology. Its optical bandgap is approximately 1.42 eV, and it possesses a suitable conduction band position, indicating its capability to facilitate solar-driven water splitting and absorb visible light. Under AM 1.5 simulated solar illumination, the photocurrent density of 12 μA/cm2 was attained in a 1 mol NaOH solution. However, the prepared CuFe 2 O 4 films demonstrate instability under constant light in the electrolyte owing to the copper reduction reaction. These research results offer a fresh insight into the potential application of CuFe 2 O 4 as a photocathode semiconductor in PEC water splitting. • P-type CuFe 2 O 4 thin films were fabricated for the first time by spray pyrolysis. • The critical physical and photophysical characteristics of the films were analyzed. • The films have suitable band positions for hydrogen production by water splitting. • The highest photocurrent density of 12 μA/cm2 was attained at 0.7 V vs. RHE. [ABSTRACT FROM AUTHOR]

TeO2 single crystal has drawn much attention in recent years due to its excellent acousto‐optic (AO) performance in the field of spectral imaging and optical processing. The optical properties of TeO2 single crystal are critical for the fabrication of AO devices. To improve the optical properties of the TeO2 single crystal, Mn4+ ions were doped into the TeO2 lattice. Herein, bulk TeO2 single crystal and TeO2:0.02Mn4+ single crystal have been successfully grown by a Bridgman method. Compared with the TeO2 single crystal, a 30% transmittance increase was observed in the TeO2:0.02Mn4+ single crystal. Furthermore, the TeO2:0.02Mn4+ single crystal shows a smaller extinction coefficient (≤0.01) in the Vis–NIR region, indicating less optical loss. The bandgap energy of TeO2:0.02Mn4+ was broadened from 3.360 to 3.635 eV. In addition, TeO2:0.02Mn4+ single crystal exhibits a higher refractive index (about 2.244), which indicates that TeO2:0.02Mn4+ single crystal is a potential medium for high‐efficiency AO devices. [ABSTRACT FROM AUTHOR]

An electrochemical deposition technique was employed to synthesize FeS material. The Iron nitrate nonahydrate (Fe(NO3)2.9H2O) and sodium sulphate (NaSO4) are part of the electrochemical bath system. The films synthesized have a polycrystalline structure with diffraction peaks and a preferred orientation along the (111) diffraction plane. The significance of high peaks lies in their ability to provide a spacious surface area for efficient photovoltaic activities. By increasing the deposition time of FeS, the film thickness decreased from 108.98 to 100.87 nm. The FeS absorbance decreases as the wavelength approaches the VIS-IR region. The FeS material had the highest absorbance value at 30 s across the entire spectrum, averaging a maximum of 0.072 in the ultraviolet region. The films deposited had energy band gaps ranging from 2.12 to 1.58 eV. The energy band gap also decreased as the deposition time and film thickness decreased. The bandgap energy range found in this study is perfect for absorbing solar energy radiation above 1.58 eV, making it ideal for solar cell absorber layers.

This paper outlines the investigation of structural, dielectric, complex impedance and optical properties of lanthanum-modified (Bi0.5La0.5Fe)0.5(Bi0.5Na0.5Ti)0.5O3 (BLF–BNT) single perovskite oxide synthesized by conventional solid-state reaction method. From Rietveld refinement, the crystal structure of the BLF–BNT ceramic has confirmed a tetragonal and the estimated average crystallite size is found to be 43.6nm. The dielectric properties of the La-doped BLF–BNT ceramic reveal the presence of Maxwell–Wagner-type dielectric dispersion. This suggests the occurrence of charge accumulation at grain boundaries and interfaces within the material. The complex impedance and complex electric modulus studies were employed to gain insight into the microscopic dielectric relaxations and conduction processes of the material. The electric modulus spectroscopy reveals the existence of nonDebye-type relaxation processes, including localized and long-range relaxation processes. The Nyquist and Cole–Cole plots show the semiconducting nature of the BLF–BNT ceramic. With the help of the Arrhenius method based on the imaginary portion of the electrical impedance and modulus, activation energies and relaxation times have been estimated. These parameters contribute to a deeper understanding of the electrical properties and conduction mechanisms within the material. Further, Raman spectroscopy, a nondestructive chemical analysis technique, was conducted to confirm the composition and structural integrity of the proposed system through its atomic vibrations. Also, the bandgap energy of the material has been estimated using Tauc’s relation and is found to be 1.69eV.This signifies that the BLF–BNT ceramic possesses a suitable bandgap for certain device applications, making it a promising candidate in various technological fields. Moreover, the overall comprehensive study of the proposed ceramic provides valuable insight and opens new possibilities for its potential applications in various electronic devices. [ABSTRACT FROM AUTHOR]

This study reports on the deposition of highly transparent conducting n-type zinc oxide (ZnO) thin films on FTO substrates, via an optimized doping process. Our work is focused on doping zinc oxide with vanadium (V) using spray pyrolysis technique and ensure the synthesis of nanoparticles-shaped ZnO, with an improved optical, microstructural and electrical properties for solar cells applications, as optical window material. Undoped and V-doped ZnO thin films, with careful optimized amounts (2, 4, 6 and 8 at.%), were grown at maintained 550∘C pre-heated substrate during the deposition process, which enables us to obtain nano-sized ZnO particles. We proved that 4 at.% is the optimum V content that enhances the crystallinity of the grown thin film noticeably. With an average transmittance of 80%, the deposited thin films revealed high transparency in the visible domain with a slight decrease in optical transmission which might result from additional scattering. UV-Visible analysis showed that increasing V amounts, a resulting decrease in the energy bandgap ( E g ) is obtained from 3.26 eV to 3.17 eV for 4 at.% of V content. Moreover, deep level defects in zinc oxide can be reduced with vanadium doping and consequently strengthen the UV emission. The UV emission peak intensity rises with increasing V-doping amount then decreases slightly at 8% of V content. The electrical properties measurements showed a decrease in resistivity from 2.8 10 − 2 Ω ⋅ cm to 0.9 10 − 2 Ω ⋅ cm when doping with 4 at.% of V. The crucial effect of the V-doping of ZnO was also demonstrated via the enhancement of carrier mobility that attains 38.5 cm2/V ⋅ s at the optimum vanadium content. The photocurrent analysis revealed much higher visible light absorption in the V-doped zinc oxide thin films than that of undoped film. The photocatalytic activity enhancements are attributed to the lower recombination rate of the photogenerated electron-hole pairs, the narrowed bandgap, yielding a higher photocatalytic performance. [ABSTRACT FROM AUTHOR]

In this work, the bandgap energy of Si samples doped with impurity atoms of elements Ga (AIII) and Sb (BV) by the diffusion method and without impurity atoms was studied. It is known that the bandgap energies of GaSb and Si semiconductors at room temperature are 0.726 and 1.12 eV, respectively. According to the results of the study, it was found that the band gap energies of Ga and Sb-doped and non-doped Si samples are 1.114 and 1.119 eV, respectively. When the samples were further annealed at a temperature of 600 °C, it was observed that the bandgap energy of the samples doped with Ga and Sb decreased to 1.10 eV. [ABSTRACT FROM AUTHOR]

The exciton binding energy (Eb) is a key parameter that governs the physics of many optoelectronic devices. At their best, trustworthy and precise measurements of Eb challenge theoreticians to refine models, are a driving force in advancing the understanding of a material system, and lead to efficient device design. At their worst, inaccurate Eb measurements lead theoreticians astray, sow confusion within the research community, and hinder device improvements by leading to poor designs. This review article seeks to highlight the pros and cons of different measurement techniques used to determine Eb, namely, temperature‐dependent photoluminescence, resolving Rydberg states, electroabsorption, magnetoabsorption, scanning tunneling spectroscopy, and fitting the optical absorption. Due to numerous conflicting Eb values reported for halide perovskites (HP) and transition metal dichalcogenides (TMDC) monolayers, an emphasis is placed on highlighting these measurements in an attempt to reconcile the variance between different measurement techniques. It is argued that the experiments with the clearest indicators are in agreement on the following values: ≈350–450 meV for TMDC monolayers between SiO2 and vacuum, ≈150–200 meV for hBN‐encapsulated TMDC monolayers, ≈200–300 meV for common lead‐iodide 2D HPs, and ≈10 meV for methylammonium lead iodide. [ABSTRACT FROM AUTHOR]

P -type copper niobate (CuNb 2 O 6) was prepared for the first time by a two-step spray pyrolysis method on FTO glass substrates. Its feasibility in photoelectrochemical (PEC) decomposition water was systematically evaluated. The physical and photophysical properties of the thin film, including band edge position, bandgap energy, carrier lifetime, and incident photo-to-current efficiency (IPCE), were characterized and analyzed. The optical band gap of the prepared gray CuNb 2 O 6 film is ∼1.41 eV, which indicates that it can absorb visible light and achieve sunlight-driven water splitting. The photocurrent density under simulated sunlight at AM1.5 was 0.25 mA/cm2, and the IPCE value could reach up to 3% at 400 nm in an aqueous solution (pH = 6.8) when applying a bias of 0.4 V vs. RHE. Despite exhibiting a good optical band gap and photocurrent density, the fabricated p -CuNb 2 O 6 thin films remained unstable under illumination in aqueous solutions due to the reduction reaction of copper. Based on these findings, this study provides a new opinion on the applicability of CuNb 2 O 6 as a photocathode material for PEC water splitting. P -type copper niobate (CuNb 2 O 6) was prepared for the first time by a two-step spray pyrolysis method on FTO glass substrates. Its feasibility in photoelectrochemical (PEC) decomposition water was systematically evaluated. The physical and photophysical properties of the thin film, including band edge position, bandgap energy, carrier lifetime, and incident photo-to-current efficiency (IPCE), were characterized and analyzed. [Display omitted] • P -type copper niobate (CuNb 2 O 6) was prepared for the first time by a two-step spray pyrolysis method. • The physical and photophysical properties of the thin films were characterized and analyzed. • The highest photocurrent density of −0.25 mA/cm2 was obtained at 0.4 V vs. RHE. • This study provides a new opinion on the applicability of CuNb 2 O 6 as a photocathode material for PEC water splitting. [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive study on the synthesis, characterization, and analysis of the structural, optical, dielectric, and electrical properties of barium-doped lead titanate PbTiO3 (PT) ceramics. The hydrothermal synthesis method was employed to fabricate the Ba-doped PbTiO3 ceramics, followed by sintering at 1000 °C for 4 h. X-ray diffraction analysis reveals a transition from a tetragonal to pseudo-cubic crystal structure with increasing barium concentration, accompanied by changes in lattice parameters. Raman spectroscopy confirms characteristic phonon modes of the tetragonal phase, with broadening and intensity changes indicating the presence of defects induced by barium doping. UV–Vis–NIR spectroscopy shows increased absorption in the ultraviolet region, suggesting modified optical properties. The band gap energy values also increase with barium content. Dielectric measurements demonstrate the impact of barium doping on the dielectric behavior, with higher dielectric constants observed for higher barium concentrations. The modified Uchino plots reveal parameters γ and δ, providing insights into the electrical properties and dielectric response. Overall, this study highlights the structural modifications, optical changes, and dielectric behavior induced by barium doping in PbTiO3 ceramics. [ABSTRACT FROM AUTHOR]

In this study, we synthesize MXene/Graphene/NiO composite via the in situ precipitation technique. The CV plots exhibited redox peaks, which served as evidence of the presence of faradaic processes. We estimated the specific capacitances of MXene (Ti3C2TX), Graphene, and MXene/Graphene/NiO composite at scan rates of 10, 20, 30, 40, and 50 mV/s. The values obtained were 1250, 625, 416, 312, and 250 F/g for MXene, 972, 486, 324, 243, and 194 F/g for Graphene, and 1666, 847, 564, 423, and 338 F/g for the MXene/Graphene/NiO composite. The specific capacitance values obtained from GCD analysis are estimated to be 139.111, 183.244, 276.483, and 558.788 F/g for MXene (Ti3C2TX), Graphene, and MXene/Graphene/NiO composite, respectively. At a current density of 2.0 A/g, the energy densities obtained for MXene (Ti3C2TX), Graphene, and MXene/Graphene/NiO composite are 100.159, 100.159, and 100.159, respectively. The absorption rate of the graphene, MXene (Ti3C2Tx), and MXene/Graphene/NiO composite is between 0.02 and 0.21, 0.92 to 1.69, and 0.32 to 1.19 a.u. respectively. The graphene has a transmittance value of 90.4%, MXene (Ti3C2Tx) has a transmittance value of 10.3%, and MXene/Graphene/NiO composite has a transmittance value of 49.2%. In terms of energy bandgap, the graphene, MXene (Ti3C2Tx), and MXene/Graphene/NiO composite have values of 0.8, 1.59, and 1.75 eV respectively. The synthesized material has specific capacitances that are well-suited for high-performance energy storage devices.

In this study, electrochemical deposition was used to synthesize SrS-doped zirconium materials at a varying voltage of deposition. The XRD result shows that SrS/Zr has a prominent peak intensity corresponding to 2theta values of 26.45o, 33.86o, 38.01o, and 51.49o. The crystal lattice is shown by the prominent peak intensity with higher 2theta degree values; the appearance of an unindexed peak is caused by the substrate utilized for the deposition. SrS surface morphology reveals a Clove-like surface with precipitate visible in the SrS micrograph; the large grain size on the surface of the substrate exhibits photon absorption but lacks any signs of pinholes. At the introduction of zirconium as a dopant to the SrS precursor, there was a drastic change in the precursor which is also noticed on the surface micrograph of the analyzed films. The films show a decrease in thickness from 129.14 to 120.09 nm and an increase in film resistivity from 1.24 x 109 to 1.29 x 109 ohm.m, which further led to a decrease in conductivity from 8.06 x 108 to 7.75 x 108 S/m. The impact of the deposition voltage on the reflectance reveals that lower voltage will stabilize the reflectance of SrS/Zr which will be useful for photovoltaic applications. SrS has an energy bandgap of 1.50 eV while SrS/Zr with bandgap energy of 2.00 – 2.50 eV.

Fe-based spincrossover (SCO) molecular complexes have shown to exhibit spincrossover behavior when subjected to stimuli such as heat, light and pressure. In a previous work, solutions of Fe-based spincrossover (SCO) molecular complexes with increasing ligand length, CnH2n+1NH2 (n = 12, 14, 16) of Fe(L12)2](BF4)2, [Fe(L14)2](BF4)2, and [Fe(L16)2](BF4)2, have shown to produce ultrahigh Seebeck coefficients when subjected to a temperature gradient. In this work, these three compounds are dissolved in dimethyl sulfoxide (DMSO) and subjected to temperature dependent Ultraviolet-visible (UV-vis) spectrometry. This optical characterization method was used to provide a correlation between the ligand length of the SCO complex and the bandgap energy measured. Subsequently, these findings were also triangulated with the effect of the ligand length on ionic conductivity and the Seebeck voltage. This work thus provides a systematic molecular understanding of the optical and electronic characteristics of SCO complexes, which paves the way for molecular design strategies in utilization of SCO for applications such as energy conversion and sensors. [ABSTRACT FROM AUTHOR]

This study examines the impact of drying temperature and drying time on the degree of crystallinity of the Zn(II)- tartrate complex. Crystallinity degree is one of many important factors in material science which may alter the properties and applications of transition metal complexes. The Zn(II)-tartrate was synthesized using a direct mixing solution method at room temperature. Drying temperature and drying time were varied at 80 (C, 100 (C, and 120 (C for 1 and 2 h, respectively. The obtained white solid of Zn(II)-tartrate was characterized by FTIR and powder-XRD. Analysis by FTIR and powder XRD confirms that Zn(II)-tartrate was successfully synthesized and has considerably good crystallinity degree. The crystallinity of Zn(II)-tartrate is influenced by the temperatures and drying times. The higher the temperature and the longer the drying time, the higher the degree of crystallinity of Zn(II)-tartrates obtained. The crystallinity degrees and crystallite size of the Zn(II)-tartrates obtained in this work were around 74–75% and 16 nm, respectively. Further analysis of the selected sample by DTA-TGA analysis shows that the complex has a good thermal stability up to 300 (C. Moreover, the DRS spectrum shows that Zn(II)-tartrate absorbs UV light at 200–236 nm with a direct bandgap energy of 5.54 eV, which is slightly higher than the KNatartrate precursor. [ABSTRACT FROM AUTHOR]

Catalytically active chromium-manganese oxides (CMO) were synthesized by the sol-gel route for the partial oxidation of propane to propene. The effects of calcination temperature and time on the catalytic performance of the CMO were examined in a fixed bed reactor within 300–600 °C at a gas hourly space velocity (GHSV) of 6,000 mL·g−1 cat ·h−1. Structural and morphological analysis disclosed nano-crystallite sizes and spherical shapes with smooth and tiny particles. The introduction of Cr tends to increase the specific surface area, decrease the pore diameter and crystallite size, as well as the bandgap energy of the obtained samples, which promoted the movement of abundant lattice oxygen. Based on the light-off curves, the catalyst CM32 (CMO calcined at 300 °C@2 h), with low calcination temperature and long calcination time, achieved the best performance and stability. CM32 exhibited the highest selectivity and yield, 79.35% and 29.80%, respectively. CM32 owned a reaction rate of 2.93 mol·g−1 cat ·s-1 and apparent activation energy of 49.52 kJ mol-1, which could be related to not only its higher quantity of lattice oxygen (O2−) and Cr6+/Cr3+ ratio, but also to the decrement in pore diameter size and bandgap energy. The reaction pathway was proposed based on the MvK mechanism for the propane partial oxidation. Moreover, CM32 maintained its catalytic performance after a stability test of 100 h' time-on-stream. The highly stable and active CM32 catalyst obtained shows good potential for partial oxidation of propane to propene. [ABSTRACT FROM AUTHOR]

This study describes the synthesis of 2,5-Bis(3,4-dialkoxy phenyl) Thiazolo[5,4-d} thiazoles (DAITn) (I) and its subsequent structural analysis. These compounds were prepared via reaction of dithio-oxarnidc with the freshly prepared 3,4-dialkoxy benzaldehyde in (DMF). The structure of DAITn (I) was found to have the 3 and 4 positions of the two benzene rings substituted with (OCnH2n+h n=2-5) which equaled to compound M2-M5. The primary methods used for theoretical calculations in this study are quantum mechanics/molecular dynamics simulations based on Density Functional Theory (DFT) and Monte Carlo. The Gaussian09W software's B3LYP hybrid feature and 6-311++G(d,p) basis set were employed in both the gas and aqueous phase for protonated and non-protonated species at the B3LYP level. Electronic structural identifiers were discovered from geometryoptimized structures and correlations between EHOMO (higher occupied molecular orbital energy), ELUMO (lower unoccupied molecular orbital energy), (Eg) bandgap energy, (I) ionization energy, (χ) electronegativity, (ΔN) electron transfer, and (ΔE_(b-d)) back-donation energy were calculated. The Monte Carlo method was used to calculate the adsorption for all identified compounds in this study, and a Fe (110) crystal more stable surface was selected. UV-visible spectroscopy is measuring absorption coefficient, transmittance, and electrical conductivity, and uses a Tauc plot for bandgap energy of the highest absorption peaks. ADTTn molecules with a wide bandgap and a high optical conductivity. Thermodynamic parameters, molecular dynamics simulations, and adsorption energy have been examining inhibitor/surface interactions with greater binding energy leading to stronger interaction and larger negative adsorption energy value indicating a more stable interaction. A four-slab model featuring eighty iron atoms per layer, or one hundred- and ten-unit cells, was used, along with a spline transformation function and a cut-off distance of 1.85 nm for nonbonded interactions. Simulated heating was employed to progressively lower the temperature and search for a low-energy adsorption site. [ABSTRACT FROM AUTHOR]

Hydrogels doped with carbon nanotubes (CNTs) have been widely used in many areas due to the superior properties of both hydrogels and CNTs. The synthesis of homogeneously-distributed CNTs-hydrogel nanocomposites is an important research topic because the quality of the dispersion in the structure affects all observed and measured properties. In the literature, high electrical and mechanical properties of CNTs can only be transferred to the elastic hydrogels if their homogeneous distribution in the composite networks is achieved by adding functional groups. In this work, we synthesized polyacrylamide (PAAm) hydrogels doped with homogeneously-distributed multi-walled carbon nanotubes (MWCNTs) by free-radical crosslinking copolymerization in phosphate-buffered saline (PBS) solution without any functional groups. The contents of MWCNTs varied from 0.1 to 2.5 vol% with no aggregation in the PAAm hydrogel networks. The agglomeration of MWCNTs in PAAm hydrogels was prevented by rapid polymerization with catalyzer, tetramethylethylenediamine (TEMED) effect. The homogeneous distributions of MWCNTs were observed by scanning electron microscopy (SEM). UV-Vis spectroscopy was used to investigate optical properties, bandgap energies, dispersibility, refractive index, resonance and non-resonance ratios for hydrogels doped with various MWCNTs contents. Here bandgap energies of composite hydrogels were calculated by Tauc's relation. The results showed that bandgap energies of hydrogel composite decreased as MWCNTs contents increased. The mechanic deformation tests of the composites were also performed and it was observed that when MWCNTs increased, the elastic modulus of hydrogel composites increased. These well-dispersed composites are a potential candidate in different areas due to the higher electrical and mechanical properties of MWCNTs. [ABSTRACT FROM AUTHOR]

The optical energy bandgap of semiconductor materials is a critical parameter for predicting optoelectronic application of materials. Because pure semiconductors usually possess single optical absorption within the interband region, the Tauc plot has been a commonly used technique in the estimation of their energy bandgaps. However, in the case where semiconductors exhibit an absorption of the interband and an additional significant absorption of a sub-band, a direct application of the Tauc method can lead to erroneous estimates of bandgap. Also pertinent to note is the rarely explored/ reported influence of the vertical axis scale of the Tauc's plot on estimated bandgap value. These errors frequently appear in many publications in which authors incorrectly determine bandgap energy by neglecting the absorption of the sub-band, or by starting the vertical axis scale of the Tauc's plot from a non-origin. Like the efforts made by a few other researchers, the present work investigates the influence of the secondary absorption and the vertical axis scale of the Tauc's plot on estimated bandgap values. It is found that the absorption of the sub-band must be considered alongside the absorption of the interband to obtain a correct bandgap estimate. Also, the vertical axis scale must be started from the origin otherwise the determined bandgap would be slightly incorrect. The optical spectra of synthesized intrinsic ZnO, Ga2O3-modified TiO2 and Zn-doped β-Ga2O3 films are used for this study. The prepared films are characterized using field-emission scanning electron microscope, energy dispersive X-ray spectroscopy, X-ray diffraction, and ultraviolet–visible near infrared spectroscopy. [ABSTRACT FROM AUTHOR]

In the research electrochemical deposition technique was use in deposition of undoped SrS and doped SrS with silver were 0.01 mol of thioacetamide (C2H5NS), 0.1 mol of strontium chloride hexahydrate (SrCl2.6H2O), and 0.01 mol of silver nitrate (AgNO3) were utilized as the cationic, anionic, and dopant concentrations. The XRD spectra of the SrS and SrS doped silver showed prominent crystalline peaks at angles of 26.69°, 37.97°, 51.39°, and 65.56° for SrS and 26.42°, 33.42°, 37.98°, and 51.32° for SrS/Ag, respectively, with corresponding diffraction planes (111), (112), (200), and (211). However, the diffraction pattern shows that the peak intensity increases as the deposition voltage increases. The undoped SrS material morphology has a clove-like substance with precipitate; the large nano grain on the substrate's surface exhibits photon absorption but shows no traces of pinholes. When doped SrS is deposited at various precursor voltages, it forms uniform surfaces devoid of pinholes. The cell also penetrates the substrate being used for the deposition, as seen by the elemental makeup of the films. It was observed that SrS/Ag at 10V and 12V had little precipitate on the surfaces; this is because a carbon electrode was utilized, which tends to react with electrolyte at low voltages but does not do so at 14V. The films show that when the deposition voltage increased, the electrical resistivity decreased from 1.42 x 109 to 1.37 x 109 Ω.m and the thickness decreased from 125.02 to 123.025nm. This further led to an increase in conductivity from 7.04 x 108 to 7.29 x 108 S/m. It was discovered that the absorbance decreases as the electromagnetic radiation's wavelength grows and the deposition voltage rises. According to research done on the deposited material, its energy bandgap lies between 1.55 and 2.51 eV.

Polyethylene oxide‐poly(3,4‐ethylenedioxythiophene) (PEO‐PEDOT) nanocomposite films ‐ incorporated with NiZnFeO4 nanoparticles (NPs) were deposited using a dip‐coating technique. X‐ray diffraction (XRD) analysis revealed peaks at 35.4, 43.2, 54.5, and 56.3° diffraction angles, corresponding to NiZnFeO4NPs diffraction planes of 311, 400, 422, and 511, respectively. The PEO‐PEDOT film exhibited a smooth amorphous nature with a sheet nanostructure behavior. The incorporation of NiZnFeO4NPs NPs into the PEO‐PEDOT nanocomposite films led to an increase in surface roughness and thermal stability. The nanocomposite films also exhibited sheet nanostructure behavior as observed by SEM micrographs. The bandgap energies of the films, as deduced from the Tauc plot, exhibited a monotonic decrease from 3.91 to 3.60 eV as the NiZnFeO4NPs concentration increased from 0 to 8 wt%. A mathematical model was formulated to predict the bandgap energies versus NiZnFeO4NPs concentration. Additionally, the electrical conductivity of the nanocomposite films increased monotonically from 0.46 to 1.30 mS cm−1 as the NiZnFeO4NPs concentration increased from 0 to 8 wt%, as determined by 4‐point probe. The observed correlation between the optical and electrical properties of the nanocomposite films indicates promising prospects for utilizing these materials in optoelectronic devices. [ABSTRACT FROM AUTHOR]

Lanthanides (Ce, Pr, Nd and Gd) 1, 3, 5 and 10 wt% of each were loaded into a pristine sodium aluminium phosphate glass matrix in order to simulate the immobilization of minor actinides (Am, Np, Cm) produced from spent nuclear fuel reprocessing. The optical parameters pertaining to these glasses were derived from the diffuse reflectance spectra. The systematic dependence of the physical and structural properties of these glasses on the dopants and the concentration of the latter was studied by XRD and Raman spectroscopy. The results on Rare Earth (RE) doped sodium aluminium phosphate are being reported for the first time. The physical parameters such as density, molar volume and oxygen packing density were evaluated. The XRD patterns showed the absence of any crystalline phase in these glasses. The relative % areas of (PO3)−2(Q2) bonds increase, whereas Q0 and Q1 tend to decrease with the addition of lanthanide oxides as compared to the pristine glass. The addition of different lanthanide oxides was found to depolymerize the network by forming more Q2 short chains. The results showed that the band gap energy (Eg) depends strongly on the cation field strength (CFS) of the lanthanides. The band gap energy decreases with an increase in the lanthanide concentration in the glass matrix. Praseodymium-doped glasses showed the highest Eg values (5.28–5.23 eV). The photoluminescence spectra confirm the characteristic excitation and emission peaks for the cations Ce+3, Pr+3 and Gd+3 and their variation with concentration was analysed. [ABSTRACT FROM AUTHOR]

We study structural, electronic and optical properties of inorganic leadfree halide perovskites RbGeX3 (X = Cl, Br and I) under hydrostatic pressure, which could facilitate development of new optoelectronic and solar-cell technologies. ab initio first-principles calculations are employed based on the generalized gradient approximation within the framework of density functional theory. We demonstrate that the bandgap of our perovskites decreases with increasing pressure. At a given pressure, the bandgap becomes narrower when the halogen atom is changed from Cl to I. We also examine the density of states and demonstrate that the energy levels near the Fermi level change significantly under pressure. The optical properties are calculated using the density functional perturbation theory and the Kramers-Kronig relation. The optical parameters such as the real and imaginary parts of the dielectric function, the refractive index and the absorption coefficient are calculated under different pressures. [ABSTRACT FROM AUTHOR]

The optical properties of TlIn(S0.25Se0.75)2 crystals were studied by ellipsometry measurements. X-ray diffraction pattern presented well-defined peaks associated with monoclinic structure. Energy dependent graphs of various linear optical parameters of the crystal were presented in the 1.25–4.50 eV range. The band gap and Urbach energies of the compound were found as 1.96 and 0.68 eV, respectively, from the analyses of the absorption coefficient. Refractive index spectrum was analyzed considering the single-effective-oscillator model to get oscillator and dispersion energies, zero and high frequency dielectric constants, plasma frequency. Moreover, the nonlinear refractive index, first-order and third-order nonlinear susceptibilities of TlIn(S0.25Se0.75)2 crystal were revealed in the present paper. [ABSTRACT FROM AUTHOR]

The intrinsic absorption edge of a β - Ga 2 O 3 single crystal is examined by spectroscopic ellipsometry. An absorption model consisting of five parameters including absorption amplitude, bandgap energy, Urbach energy and two power exponents is developed to describe the absorption characteristics of the β - Ga 2 O 3 single crystal. The anisotropic bandgap energies obtained from the model are 4.938, 5.030 and 5.100 eV, respectively. These values obtained from the model agree well with values derived from the first derivative maximum of k and maximum of n method. [ABSTRACT FROM AUTHOR]

The current study focuses on the physical and structural aspects of B 2 O 3 –CdO–ZnO–Na 2 O glasses that have been reinforced by MoO 3 ions. The samples were experimentally prepared using a melt quenching procedure, and then the absence of strong peaks in the XRD spectra confirms their amorphous nature. A variety of optical, Raman, and radiationshielding qualities were evaluated and described. The structural changes in the material were investigated using FTIR and Raman spectra. The density of the samples rose when MoO 3 was added, implying that BO 3 was transformed into BO 4 units. The transition of Mo6+ to Mo5+ ions is responsible for the reduction in band gap in these glasses. Because of the vacancy generated by the oxygen units, the Urbach energy increased, implying the generation of additional defects. The presence of diverse structures present in the structure of the glass was revealed by FTIR and Raman spectra, such as MoO 6 , BO 3 , BO 4 , metaborates, pyroborates, and so on. The transition of BO 3 to BO 4 units, which is crucial in density analyses, was also corroborated by Raman spectra. Using FLUKA simulation and XCOM estimations, the mass attenuation coefficient of the glasses improved with the amount of MoO 3. At 15 keV, the half-value layer of 0.0103 cm, 0.01019 cm, 0.01016 cm, 0.0101 cm, and 0.01005 cm was obtained for glasses with an MoO 3 concentration of 0, 0.5, 1, 1.5, and 2.0 mol% respectively. The optimum MoO 3 concentration for fast and thermal neutron cross-sections was 0.5 and 2.0 mol% respectively. The glasses are viable materials for environmentally friendly and transparent radiation barriers in nuclear facilities. [ABSTRACT FROM AUTHOR]

In this research, we attempted to modify the bandgap of anodic titanium oxide by in situ incorporation of selected elements into the anodic titanium oxide during the titanium anodization process. The main aim of this research was to obtain photoactivity of anodic titanium oxide over a broader sunlight wavelength. The incorporation of the selected elements into the anodic titanium oxide was proved. It was shown that the bandgap values of anodic titanium oxides made at 60 V are in the visible region of sunlight. The smallest bandgap value was obtained for anodic titanium oxide modified by manganese, at 2.55 eV, which corresponds to a wavelength of 486.89 nm and blue color. Moreover, it was found that the pH of the electrolyte significantly affects the thickness of the anodic titanium oxide layer. The production of barrier oxides during the anodizing process with properties similar to coatings made by nitriding processes is reported for the first time. [ABSTRACT FROM AUTHOR]

Co-doped ZnO thin films (CAZO) were prepared by DC magnetron sputtering. The structural, electrical and optical properties of thin films were investigated using X-ray diffraction (XRD), atomic force microscopy (AFM), optical spectrophotometer and Raderford Back Scattering (RBS) techniques. The CAZO thin films with different thicknesses had an amorphous structure. The particle distribution diagram showed that with the increase in thickness, the size of nanoparticles reached from 10 nm to 25 nm and the range of particle size changes also increased. The bandgap energy decreased with the increase in thickness, but the Urbach energy increased. The CAZO thin film with a thickness of 50 nm had lower activation energy and a higher concentration of donor carriers, but with increasing thickness, the concentration of this type of carriers (n-type) decreases, because the conduction in the layers decreases and the resistance in CAZO thin films with a thickness of 150 nm has increased. [ABSTRACT FROM AUTHOR]