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Polymethine dyes of tetraanionic nature comprising 1,3,2‐dioxaborine rings in the polymethine chain and end‐groups of different electron‐accepting abilities have been synthesized. They can be considered as oligomeric polymethines, where a linear conjugated π‐system passes through three 1,3,2‐dioxaborine units and a number of tri‐ and dimethine π‐bridges between two end‐groups. The obtained dyes exhibit near‐infrared absorption and fluorescence, with molar absorption coefficients reaching as high as 564000 M−1 cm−1 in DMF, rendering them among the strongest absorbers known. The novel compounds are bright NIR fluorophores, with fluorescence quantum yields up to 0.13 in DMF. A comparative analysis of the electronic structure of the obtained dyes with respective dianionic and trianionic oligomers was conducted through quantum chemical calculations. [ABSTRACT FROM AUTHOR]

Two-dimensional van der Waals heterostructures have good application prospects in solar energy conversion due to their excellent optoelectronic performance. In this work, the electronic structures of Sc2CF2/Sc2CCl2, Sc2CF2/Sc2CBr2, and Sc2CCl2/Sc2CBr2 heterostructures, as well as their properties in photocatalysis and photovoltaics, have been comprehensively studied using the first-principles method. Firstly, both of the three thermodynamically and dynamically stable heterostructures are found to have type-II band alignment with band gap values of 0.58 eV, 0.78 eV, and 1.35 eV. Meanwhile, the photogenerated carriers in Sc2CF2/Sc2CCl2 and Sc2CF2/Sc2CBr2 heterostructures are predicated to follow the direct Z-scheme path, enabling their abilities for water splitting. As for the Sc2CCl2/Sc2CBr2 heterostructure, its photovoltaic conversion efficiency is estimated to be 20.78%. Significantly, the light absorption coefficients of Sc2CF2/Sc2CCl2, Sc2CF2/Sc2CBr2, and Sc2CCl2/Sc2CBr2 heterostructures are enhanced more than those of the corresponding monolayers. Moreover, biaxial strains have been observed to considerably tune the aforementioned properties of heterostructures. All the theoretical results presented in this work demonstrate the application potential of Sc2CX2/Sc2CY2 (X, Y = F, Cl, Br) heterostructures in photocatalysis and photovoltaics. [ABSTRACT FROM AUTHOR]

A series of TiN/ITO composite films with various thickness of ITO buffer layer were fabricated in this study. The enhancement of optical properties was realized in the composite thin films. The absorption spectra showed that absorption intensity in the near-infrared region was obviously enhanced with the increase of ITO thickness due to the coupling of surface plasma between TiN and ITO. The epsilon-near-zero wavelength of this composite can be tuned from 935 nm to 1895 nm by varying the thickness of ITO thin films. The nonlinear optical property investigated by Z-scan technique showed that the nonlinear absorption coefficient (β = 3.03 × 10−4 cm/W) for the composite was about 14.02 times greater than that of single-layer TiN films. The theoretical calculations performed by finite difference time domain were in good agreement with those of the experiments. [ABSTRACT FROM AUTHOR]

The rapid advancements in material research for lead‐free inorganic metal halide perovskites have fueled the pathway to design environmentally benign solar‐cells to cater the energy requirements for future generations. The vacancy‐ordered double‐perovskite Cs2SnI6 with an optimum band‐gap (≈1.3 eV), high absorption coefficient (≈105 cm−1), ambi‐polar charge carrier transport, and high structural and compositional stability coupled with simple cost‐effective solution‐based synthesis techniques seems to be an excellent candidate to design air‐stable high‐efficiency solar‐cell‐based applications. The review focusses on the structure–property relationship in Cs2SnI6 and its critical dependency on growth precursors, conditions, and methods. The recent advancements in material and additive engineering to obtain phase‐pure uniform and continuous Cs2SnI6 films and myriad methods to modulate its optoelectronic properties are summarized. The nature, origin, and type of charge‐carriers in intrinsic and doped Cs2SnI6 are extensively discussed. The applications of Cs2SnI6 in different solar‐cell configurations are critically reviewed and its recent progress and challenges to achieve the ultimate theoretical Shockley–Queisser limit of 30–33% is presented. The recent experimental findings on the stability and performance of Cs2SnI6‐based solar‐cells under ambient and controlled conditions would be discussed to highlight its feasibility for the design and development of air‐stable high‐efficiency solar‐cells. [ABSTRACT FROM AUTHOR]

Photocages, also known as photoactivated protective groups (PPGs), have been utilized to achieve controlled release of target molecules in a non-invasive and spatiotemporal manner. In the past decade, BODIPY fluorophores, a well-established class of fluorescent dyes, have emerged as a novel type of photoactivated protective group capable of efficiently releasing cargo species upon irradiation. This is due to their exceptional properties, including high molar absorption coefficients, resistance to photochemical and thermal degradation, multiple modification sites, favorable uncaging quantum yields, and highly adjustable spectral properties. Compared to traditional photocages that mainly absorb UV light, BODIPY-based photocages that absorb visible/near-infrared (Vis/NIR) light offer advantages such as deeper tissue penetration and reduced bio-autofluorescence, making them highly suitable for various biomedical applications. Consequently, different types of photoactivated protective groups based on the BODIPY skeleton have been established. This highlight provides a comprehensive overview of the strategies employed to construct BODIPY photocages by substituting leaving groups at different positions within the BODIPY fluorophore, including the meso-methyl position, boron position, 2,6-position, and 3,5-position. Furthermore, the application of these BODIPY photocages in biomedical fields, such as fluorescence imaging and controlled release of active species, is discussed. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) materials are attracting much attention as emerging photocatalytic water splitting candidates in green and clean energy applications. In this work, we designed four 2D materials, ZnPS 3 , ZnPSe 3 , CdPS 3 and CdPSe 3 , which possess high stability, moderate band-gaps (2.24–3.29 eV), and anisotropic carrier mobilities of 192.26 ─ 676.04 cm2/Vs. Besides, they also have suitable band edges of REDOX at PH = 0, which can simultaneously drive photocatalytic water splitting to produce H 2 and O 2 , and show acceptable free energy for hydrogen evolution reaction (HER) of 0.89–1.20 eV. Moreover, monolayer ZnPSe 3 and CdPSe 3 can deliver strong absorption coefficients (∼105 cm−1) from visible to ultraviolet light. As a result, they have excellent solar-to-hydrogen efficiency of 18.39% and 19.70%, suggesting they are promising photocatalytic candidates for overall water splitting. • 2D ZnPS 3 , ZnPSe 3 , CdPS 3 and CdZnSe 3 have high stability, as well as low cleavage energies of 0.21–0.25 J/m2. • They are indirect semiconductors with band-gaps of 2.24–3.29 eV, and show mobilities of 192.26–676.04 cm2/Vs at 300 K. • They also have suitable REDOX band-edges, which can drive photocatalytic water splitting to produce H 2 and O 2. • Monolayer ZnPSe 3 and CdPSe 3 have excellent solar-to-hydrogen efficiency of 18.39% and 19.70%. [ABSTRACT FROM AUTHOR]

The spectra of transmisson coefficients and absorption indices of single-domain and multidomain LaBGeO5 samples have been measured. It is shown that, to measure more exactly the optical rotation ρ, it is necessary to use the spectra of transmission coefficients not only for the cases of parallel and crossed polarizers but also at other angles between them. The obtained ρ values for both samples are described quite well by only dispersion using the Drude formula. This is in agreement with the fact that the ρ value should not change during transition to the single-domain state of the crystal at a given symmetry (P31 in the ferroelectric phase and P3121 in the paraelectric phase). It is shown that the Cherenkov-type second harmonic generation (SHG) is observed only in a polydomain sample, while the second-harmonic radiation is not polarized. The domain structure of the samples was observed by scanning electron microscopy and piezoelectric force microscopy. The presence of a labyrinth-like domain structure was shown for the multidomain sample, whereas for a single-domain sample no changes in contrast were observed within the scanned region. [ABSTRACT FROM AUTHOR]

The microperforated panel (MPP) is a resonant-type sound-absorbing material considered the next-generation sound-absorption material due to its attractive characteristics. However, the drawback of narrow bandwidth sound absorption remains a matter of concern. This study explored the impact of varying backing cavity depths and different combinations of multi-section perforation sizes on the sound absorption performance of microperforated panels (MPP). A two-microphone impedance tube was used to obtain the sound absorption coefficient (SAC) of MPP following the ISO 10534-2 standard. MPP with single-size perforation diameters of 0.5, 0.7, and 1.0 mm which were compared to multi-section MPP with combinations perforation sizes of 0.5 & 0.7, 0.7 & 1.0, and 0.5 & 1.0 mm. The investigation reveals that increasing the backing cavity depth from 1.0 cm to 3.0 cm generally shifts the sound absorption coefficient (SAC) peak to a lower frequency range and decreases the SAC peak across all MPP samples. A higher SAC peak and wider absorption bandwidth were achieved from 0.5 mm single-size perforation diameter MPP and its combination in multi-section perforation MPP. [ABSTRACT FROM AUTHOR]

We present a goniometer designed for capturing spectral and angular-resolved data from scattering and absorbing media. The experimental apparatus is complemented by a comprehensive Monte Carlo simulation, meticulously replicating the radiative transport processes within the instrument's optical components and simulating scattering and absorption across arbitrary volumes. Consequently, we were able to construct a precise digital replica, or "twin", of the experimental setup. This digital counterpart enabled us to tackle the inverse problem of deducing optical parameters such as absorption and scattering coefficients, along with the scattering anisotropy factor from measurements. We achieved this by fitting Monte Carlo simulations to our goniometric measurements using a Levenberg–Marquardt algorithm. Validation of our approach was performed using polystyrene particles, characterized by Mie scattering, supplemented by a theoretical analysis of algorithmic convergence. Ultimately, we demonstrate strong agreement between optical parameters derived using our novel methodology and those obtained via established measurement protocols. [ABSTRACT FROM AUTHOR]

Significance: The estimation of tissue optical properties using diffuse optics has found a range of applications in disease detection, therapy monitoring, and general health care. Biomarkers derived from the estimated optical absorption and scattering coefficients can reflect the underlying progression of many biological processes in tissues. Aim: Complex light--tissue interactions make it challenging to disentangle the absorption and scattering coefficients, so dedicated measurement systems are required. We aim to help readers understand the measurement principles and practical considerations needed when choosing between different estimation methods based on diffuse optics. Approach: The estimation methods can be categorized as: steady state, time domain, time frequency domain (FD), spatial domain, and spatial FD. The experimental measurements are coupled with models of light--tissue interactions, which enable inverse solutions for the absorption and scattering coefficients from the measured tissue reflectance and/or transmittance. Results: The estimation of tissue optical properties has been applied to characterize a variety of ex vivo and in vivo tissues, as well as tissue-mimicking phantoms. Choosing a specific estimation method for a certain application has to trade-off its advantages and limitations. Conclusion: Optical absorption and scattering property estimation is an increasingly important and accessible approach for medical diagnosis and health monitoring. [ABSTRACT FROM AUTHOR]

The paper studies the electron irradiation at an energy of 30 keV affecting the diffuse-reflectance spectra and integrated absorption coefficient of solar irradiance of the micron-sized mZnO powder modified by adding nY2O3 nanoparticles in the amount of 0.1 to 10 wt.%. The best content of nanoparticles is found to be 3 wt.%, when the diffuse-reflectance spectra and the integrated absorption coefficient of the modified powder are 1.41 times lower than in the initial powder. It is shown that free electrons forming during the powder irradiation, make the highest contribution to the powder degradation. [ABSTRACT FROM AUTHOR]

Hybrid gold-based perovskite derivatives typically exhibit low optical bandgaps and high optical absorption coefficients, rendering them promising for photovoltaic applications. In this study, we successfully synthesized six new hybrid gold-based perovskite derivatives, namely [(C6H8N2)(AuI4)(AuI2)](3AMPY), [(C6H14N2)(AuI4)(AuI2)](3AMP), [(C8H12N)(AuI4)](2PEAI), [(C4H14N2O)(AuI4)2](OBA), [(C6H18N2O2)3(AuI4)4(I3)2](DDA), and [(C10H26N2O3)(AuI4)(I3)](TOTA), through a straightforward and efficient hydrothermal method, achieving millimeter-sized single crystals. The structural analysis of the single crystals revealed variations in crystal structures arising from differences in constituent units and their spatial positioning relationships. First-principles calculations ascertained their high optical absorption coefficients in the visible light spectrum and indirect bandgap properties. Theoretical models indicated that the spectroscopic limited maximum efficiency (SLME) values of 3AMPY, 2PEAI, DDA, and TOTA approached approximately 30% in films of 0.5 μm thickness, signifying their potential candidacy as solar cell absorbers. [ABSTRACT FROM AUTHOR]

Atmospheric aerosols impact the Earth's climate system directly by scattering and absorbing solar radiation, and it is important to characterise the aerosol optical properties in detail. This study reports the development and validation of an airborne dual-wavelength cavity-attenuated phase-shift (CAPS) single monitor, named A2S2 (Aerosol Absorption Spectral Sizer), based on the commercial CAPS single-scattering albedo monitor (CAPS-PM SSA ; Aerodyne), to simultaneously measure the aerosol optical scattering and extinction at both 450 and 630 nm wavelengths. Replaced pressure and temperature sensors and an additional flow control system were incorporated into the A2S2 for its utilisation on board research aircraft measuring within the troposphere. The evaluation of A2S2 characteristics was performed in the laboratory and included the investigation of the signal-to-noise ratio, validation of performance at various pressure levels, optical closure studies and intercomparing with the currently validated techniques. The chamber experiments show that the A2S2 can perform measurements at sample pressures as low as 550 hPa and at sample temperatures as high as 315 K. Based on the Allan analysis results, we have evaluated that the minimum detection limit of the measurements shows that the measurements have a limit accuracy of ∼ 2 Mm-1 at 450 nm and ∼ 1 Mm-1 at 630 nm for 1 Hz measurements of both scattering coefficients (σsca) and extinction coefficients (σext). The optical closure study with size-selected polystyrene latex (PSL) particles shows that the truncation error of the A2S2 is negligible for particles with particle volume diameter (Dp) < 200 nm, while, for the larger sub-micrometre particles, the measurement uncertainty of A2S2 increases but remains less than 20 %. The average factors to correct the truncation error are 1.13 and 1.05 for 450 and 630 nm, respectively. A simplified truncation correction, dependent on the scattering Ångström exponent (SAE), was developed to rectify truncation errors of the future A2S2 field measurement data. The σsca and σext measured by the A2S2 show good agreement with the concurrent measured results from the nephelometer and the CAPS particle extinction monitor (CAPS-PM ex). The absorption coefficient (σabs) derived through the extinction-minus-scattering (EMS) method by the A2S2 also corresponds with the results obtained from the aethalometer. The A2S2 was successfully deployed during an aircraft measurement campaign (Atmospheric ChemistRy Of the Suburban foreSt – ACROSS) conducted in the vicinity of Paris and the surrounding regions. The average SSA measured during the entire ACROSS flight campaign is 0.86 and 0.88 at 450 and 630 nm, respectively, suggesting that light-absorbing organic aerosols play a significant role. The average SAE and absorption Ångström exponent (AAE) varied due to measurements in various pollution conditions. The results presented in this study indicate that the A2S2 instrument is reliable for measuring aerosol σsca and σext at both blue and red wavelengths, and it stands as a viable substitute for future airborne evaluations of aerosol optical properties. [ABSTRACT FROM AUTHOR]

In this work, the casting method was utilized to prepare thin poly(vinyl alcohol) films with silver oxide (Ag2O) and zinc oxide (ZnO) nanoparticles with different percentage weights (1%, 2%, and 3%) were produced in this study. Were created Physical attributes such as X-ray diffraction (XRD) do not include structural features. The XRD measurements showed both the hexagonal crystalline structure of ZnO, the simple cubic structure of Ag2O and the amorphous structure of PVA film. UV-visible spectroscopy was used to examine the effects of ZnONPS and Ag2ONPS on PVA's optical characteristics, including absorption, transmission spectrum, absorption coefficient, extinction coefficient, and energy gap. The experimental results of the optical properties of PVA: Ag2O-ZnO nanocomposites showed that the absorption, absorption coefficient, refractive index, of dielectric constant and optical conductivity of PVA mixture increased with increasing concentrations of Ag2O and ZnONPs, while the transmittance and energy gap decrease with increasing concentration of Ag2O and ZnONPs. This work demonstrates how an increase in Ag2O and ZnONPs affects each of these variables. [ABSTRACT FROM AUTHOR]

The heat exchange between bridges and external environments is the primary cause of the temperature effect on bridges. The complexity of the two-phase (gas–solid) heat transfer mechanism, the diversity of the surface characteristics of bridge materials, and the uncertainties of the environment in which bridges are located make the numerical calculation of the heat exchange between bridges and external environments difficult. Several studies have been conducted by scholars around the world. In this work, the research on convective and radiative heat exchange between bridges and external environments is surveyed, analyzed, and summarized. The influencing factors and calculation methods of bridge temperature are examined, and the convective heat transfer and radiation mechanisms, theoretical calculations, and experimental measurement methods used to investigate the relation between bridges and external environments are summarized and analyzed. The value determination methods for convective heat transfer and radiation absorption coefficients in the calculation of the bridge temperature field are summarized. In addition, the problems and shortcomings of current research are evaluated, and future research directions are identified and discussed. [ABSTRACT FROM AUTHOR]

The recombination of charges and thermal excitation of carriers at the interface between methylammonium lead iodide perovskite (PVK) and the carbon electrode are crucial factors that affect the optoelectronic performance of carbon-based hole transport layer (HTL)-free perovskite photodetectors. In this work, a method was employed to introduce SnS quantum dots (QDs) on the back surface of perovskite, which passivated the defect states on the back surface of perovskite and addressed the energy-level mismatch issue between perovskite and carbon electrode. Performance testing of the QDs and the photodetector revealed that SnS QDs possess energy-level structures that are well matched with perovskite and have high absorption coefficients. The incorporation of these QDs into the interface layer effectively suppresses the dark current of the photodetector and greatly enhances the utilization of incident light. The experimental results demonstrate that the introduction of SnS QDs reduces the dark current by an order of magnitude compared to the pristine device at 0 V bias and increases the responsivity by 10%. The optimized photodetector exhibits a wide spectral response range (350 nm to 750 nm), high responsivity (0.32 A/W at 500 nm), and high specific detectivity (>1 × 1012 Jones). [ABSTRACT FROM AUTHOR]

This study investigated a blend of poly (lactic acid) (PLA) and Saqqez gum, with a weight ratio of 70:30, respectively, along with two plasticizers, acetyl tributyl citrate (ATBC) and polyethylene glycol (PEG), at three different concentrations (14%, 16% and 18% by weight of the PLA). The blend was analyzed using differential scanning calorimetry (DSC), scanning electron microscopy (SEM), tensile tests, water-absorption behavior (coefficients of water absorption, sorption, diffusion and permeability of the samples during 240 h) and chemical resistance (exposure to 1 mol/L HCl and 1 mol/L NaOH for 240 h). The desired elastomer blend was then used to prepare natural chewing gum, which was subsequently subjected to texture profile analyzer (TPA) tests and sensory evaluation. The results showed that the addition of both plasticizers increased the tensile properties of the blend. Compared to neat PLA, all the blends exhibited an increase in elongation at break and a decrease in yield strength, with the maximum elongation at break (130.6%) and the minimum yield strength (12.2 MPa) observed in the blend containing 16% ATBC. Additionally, all the thermal attributes studied, including Tg, Tc and Tm, were lower than those of neat PLA, and the Tg values deviated from the values predicted via Fox's equation. SEM images of the blends confirmed that plasticization improved the homogeneity and distribution of the components in the blend structure. PEG 18% and ATBC 16% exhibit the highest and lowest water-absorption behavior, respectively. Regarding chemical resistance, all blends showed weight gain when exposed to HCl, while no weight loss was observed for resistance to NaOH. The chewing gum sample obtained similar values for the mentioned tests compared to the commercial control sample. Overall, the results indicate that plasticization enhances the structure and performance of the PLA/Saqqez gum blend and further investigation is warranted. [ABSTRACT FROM AUTHOR]

In this work, we study the electric and magneto-optical absorption coefficients (ACs) and relative refractive index changes (RRICs) in W x Mo 1 − x S2 ternary alloys under the control of tungsten contents using the compact density matrix approach. With the influence of external electric and magnetic fields, the results show that there are a series of resonant peaks for both intra-band and inter-band transitions. With an increase in W-concentration and electric and magnetic fields, the resonant peaks give a blue (red) shift and reduce (increase) their amplitudes. These results suggest a potential application of monolayer W x Mo 1 − x S2 in future nanoscale electronic and magneto-optical devices. [ABSTRACT FROM AUTHOR]

Context and results: In this study, we have explored the electronic and optical properties of A2AlAgCl6 (A = Rb, Cs), revealing their potential applications in UV devices. Our investigation demonstrates that Rb2AlAgCl6 and Cs2AlAgCl6 possess remarkable mechanical and thermodynamic stability, alongside direct band gaps of 4.25 eV and 4.20 eV, respectively. The optical properties, including the dielectric function, absorption coefficient, and reflectivity, underscore the suitability of these materials for UV device applications. This work serves as a foundational reference for future experimental endeavors aiming to leverage these characteristics for practical uses in scientific research. Computational and theoretical techniques: The study utilizes first-principles calculations based on the Wien2k code, employing GGA-PBE and mBJ exchange–correlation functional to analyze the cubic structure of the space group Fm-3m. Detailed computational analyses were conducted to investigate the band structure, density of states, and optical properties, particularly focusing on Cs2AlAgCl6. This methodological approach not only confirms the materials' impressive stability and optical characteristics but also provides a robust framework for assessing their potential in UV technology applications. Our computational strategy offers insights into the effectiveness of these methodologies for future experimental validation and practical deployment in the research domain. [ABSTRACT FROM AUTHOR]

Lead-free bismuth-based perovskite halides are promising materials for optoelectronic applications owing to their lower toxicity, high absorption coefficient, and similar isoelectronic structure to (lead) Pb. Herein, we report the synthesis of Cs3Bi2Br9 perovskite quantum dots (QD) via a modified LARP method and have studied the structural and optical properties. In this study, the QD exhibits an interesting dual emission peak and a bright, unique cyan-green luminescence, with an improved photoluminescence quantum yield of 34%. Studies on Cs3Bi2Br9 QD have been reported earlier, but interestingly the origin of optical properties remains disputed and varies significantly from literature to literature. As a result of our analysis, we expect observed photoluminescence to arise from interconfigurational electronic transitions of Bi3+ ions, with an intense peak at 476 nm attributed to A-band emission and a broad emission at 498 nm attributed to emission from a lower energy level in bismuth ion. Hence, these QDs are suitable for various optoelectronic applications, such as light-emitting diodes (LEDs). [ABSTRACT FROM AUTHOR]

The effects of environmental properties on the linear and nonlinear response of Bromothymol blue (BTB) were studied. The role of the optical band gap and dielectric constant, as well as thermal conductivity, on the optical properties of the BTB molecule and the BTB complex with cetyl trimethyl ammonium bromide (CTAB) were discussed using a Z-scan instrument with a wavelength of 532 nm and power of 80 mW, a spectrophotometer, and FT-IR spectra. The orders of the nonlinear absorption coefficient, β, and the nonlinear refractive index, n2, of BTB were obtained as 10−7 cm/W and 10−12 cm2/W, respectively. The main factor in the appearance of β is reverse saturable absorption. It was observed that an enhancement of up to 5 times in the dielectric constant of the environment caused a reduction of about 6 times in the nonlinear absorption and about 2 times in the nonlinear refraction coefficient of the solution. Moreover, the CTAB complex can reduce the optical band gap of BTB by 0.7 eV and also absorbs light in the 600 to 700 nm wavelength. Therefore, it is a promising candidate for photodynamic therapy. Results of DFT calculations performed via the B3LYP method and the 6-311G(d,p) basis show an enhancement of the dipole moment of BTB with an increase in the dielectric constant of the environment. [ABSTRACT FROM AUTHOR]

The pursuit of new materials with tailored properties is essential for advancing technology. This research focuses on GaXF3 (X = Se, Si) fluoroperovskites, utilizing the density functional theory approach. The study begins by assessing structural properties, revealing stable configurations for both compounds. The results from phonon calculations confirm the thermodynamic stability of the compounds. The relationship between elastic constants, confirms their mechanical stability. Elasticity analysis using the IRelast package indicates their resilience, anisotropic characteristics, and mechanical stability. Electronic properties, including band structure, density of states, and electronic band gaps, show that both materials have a metallic nature. Additionally, optical properties, such as dielectric constants, absorption coefficients, and refractive indices, are explored, providing insights into their interactions with light for optoelectronic applications. Optical property calculations for both GaSeF3 and GaSiF3, indicate their potential suitability for use in optoelectronic devices, particularly LEDs, due to their absorption within the UV–Vis range. These results encompass properties such as reflectivity, refractive index, and absorption coefficients, indicating their relevance to potential applications in optoelectronic devices. These findings enhance our understanding of these materials and lay the groundwork for future advancements in advanced materials science. [ABSTRACT FROM AUTHOR]

This article reports the nonlinear refractive index (n2) and nonlinear absorption coefficient (β) of acid blue 129 (AB 129) dye-doped polyvinyl alcohol (PVA) thin film with different dye concentrations using Z-scan technique. The experimental technique consists of a continuous wave laser with 5 mW power working at 635 nm wavelength. The normalized transmittance curve suggests that the dye-doped polymer film exhibits a self-defocusing nonlinear index of refraction and a large nonlinear absorption coefficient ascribed to the behaviour of reverse saturable absorption. The order of third-order NLO susceptibility of the sample is estimated to be 10‒5 esu. The dye-doped polymer films show a low-limiting threshold of 0.15 kW cm–2 at 0.04 mM dye concentration and believed that the prepared thin film is a suitable candidate for application in optical limiting. The self-diffraction pattern is observed at far-field and estimated the nonlinear refractive index of the thin film using this technique. The results of the nonlinear refractive index of the sample obtained from the self-diffraction method are comparable with Z-scan results. [ABSTRACT FROM AUTHOR]

Herein, we report the nonlinear refractive index and nonlinear absorption coefficient of anthraquinone dye (disperse blue 14)-doped polymer film using a facile Z-scan technique. The Z-scan studies were carried out using a semiconductor diode laser with a constant power output of 5 mW at a wavelength of 635 nm as the source of excitation. The Z-scan technique consists of closed and open aperture methods, which revealed the self-defocusing and reverse saturable absorption mechanisms based optical nonlinearity. The third-order nonlinear optical susceptibility (χ(3)) of dye-doped polymer film was estimated to be in the order of 10–5 esu. Optical limiting (OL) behaviour of the polymer film with different dye concentrations was performed under the same experimental conditions and found to be a low OL threshold of 1.45 × 102 W cm–2 at 0.04 mM dye concentration. Self-diffraction ring pattern of the polymer film was also noticed in the far field. The overall results found that the dye-doped polymer film is a potential material for photonics and optoelectronics applications. [ABSTRACT FROM AUTHOR]

We provide a simple method that enables readily acquired experimental data to be used to predict whether or not a candidate molecular material may exhibit strong coupling. Specifically, we explore the relationship between the hybrid molecular/photonic (polaritonic) states and the bulk optical response of the molecular material. For a given material, this approach enables a prediction of the maximum extent of strong coupling (vacuum Rabi splitting), irrespective of the nature of the confined light field. We provide formulae for the upper limit of the splitting in terms of the molar absorption coefficient, the attenuation coefficient, the extinction coefficient (imaginary part of the refractive index) and the absorbance. To illustrate this approach, we provide a number of examples, and we also discuss some of the limitations of our approach. [ABSTRACT FROM AUTHOR]

In absorption spectroscopy, it is challenging to detect absorption peaks with significant differences in their intensity in a single measurement. We enable high-dynamic-range measurements by dispersing scatterers within a sample to create a broad distribution of path lengths (PLs). The sample is placed within an integrating sphere (IS) to capture all scattered light of various PLs. To address the complexities of PLs inside the IS and the sample, we performed a ray-tracing simulation using the Monte Carlo (MC) method, which estimates the measured absorbance A and PL distribution from the sample's absorption coefficient µa and scattering properties at each wavelength λ. This method was validated using dye solutions with two absorption peaks whose intensity ratio is 95:1, employing polystyrene microspheres (PSs) as scatterers. The results confirmed that both peak shapes were delineated in a single measurement without flattening the high absorption peak. Although the measured peak shapes A(λ) did not align with the actual peak shapes µa(λ), MC enabled the reproduction of µa(λ) from A(λ). Furthermore, the analysis of the PL distribution by MC shows that adding scatterers broadens the distribution and shifts it toward shorter PLs as absorption increases, effectively adjusting it to µa. [ABSTRACT FROM AUTHOR]

Perfectly diffuse sound fields play an important role in architectural acoustics and there are established theoretical characterizations of perfect diffuseness. Although sound fields in real rooms are diffuse to some extent, they are not perfectly diffuse, and therefore theories are required to describe pseudo-perfectly diffuse sound fields. Here, we aim to spatially characterize pseudo-perfect diffuseness via directional characterization of that, finite-degree spherical harmonic diffuseness. Our results show that finite-degree diffuse sound fields yield local spatial diffuseness, suggesting that spatial pseudo-perfect diffuseness is characterized using the effective radius of diffuseness. [ABSTRACT FROM AUTHOR]

A technique for estimating the sound absorption of materials under oblique incidence plane wave and diffuse field excitations is proposed. It requires a mobile loudspeaker and a pair of fixed microphones above a layer of absorbing material. Starting from sound pressure measurements made above the material surface for multiple source positions and by inverting Allard's propagation model, the proposed method allows for the identification of two effective (or equivalent) parameters, namely, the complex effective density and the complex wave number. Obtaining these parameters makes it possible to estimate the sound absorption coefficient for a plane wave with any angle of incidence or under a diffuse acoustic field by summation over the angles. The results are compared to theoretical values calculated using the Johnson-Champoux-Allard model and to reference measurements obtained using an impedance tube, a small cabin, a large reverberant room, and a sound field synthesis method. One of the limitations of this method lies in the assumptions associated with the Allard model to describe the sound field above the material (assumed to be isotropic, homogeneous, of constant thickness, and to behave like an equivalent fluid). The main advantages are (1) that the sound absorption coefficient can be estimated under oblique incidence plane wave and diffuse acoustic field with values that are always in a physical range (between 0 and 1), and (2) that samples of the order of the square meter without specific preparation can be tested which reduces the constraints associated with impedance tube or reverberant room measurements. [ABSTRACT FROM AUTHOR]

Since symmetrical geometry makes it easier to arrange pyramid absorbers on anechoic chamber walls compared to wedge absorbers, the goal of this paper is to present an optimal pyramid-shaped absorber which, in addition to the optimal performance in sound absorption, has other advantages such as less thickness, lower material consumption and cost, easier construction, arrangement and maintenance and occupying less space compared to wedges. The COMSOL Multiphysics software was used to simulate the optimized sound absorber by using the genetic algorithm programed in MATLAB software, with the goal of a 100 Hz cut-off frequency. The results show that the optimized chamfered pyramid at the top performs better at sound absorption compared to the complete pyramid and wedge with 18% less thickness. Furthermore, the cut-off frequency decreased to 91 Hz when a gap of up to 15 mm was created between the adjacent absorbers mounted on the surface, which is desirable. [ABSTRACT FROM AUTHOR]

The purpose of this study is to evaluate the effect of the number of diffusers placed in the same room, as well as the effect of diffusers with a flat area (8.4, 13.2, and 18 m2) on the calculated sound absorption coefficient in a reverberation room, when an iterative procedure based on the evaluation of the sound power level is applied (this is done by using the sound power equation and substituting with different values of equivalent absorption area on both sides of the transformed equation to reach the correct value for absorption area, which achieves equality on both sides of the equation in order to achieve the goal). The sound absorption coefficient at random incident of three materials having different degrees of absorption—has been measured in a reverberation room according to ISO 345: a highly absorbent material (sponge) a medium absorbent material (rubber) and a low absorbent material (wood).There is a noticeable convergence between the calculated and measured sound absorption coefficient from the usual ISO 354 procedure and from the sound power level equation from ISO 3741,when diffusers are present. The difference in sound power level is close to 1.0 dB depending on the position of the source with the diffuser area. Thanks to the diffusers effect, the difference between the measured and the calculated sound absorption coefficient can be considerably reduced. [ABSTRACT FROM AUTHOR]

This paper presents the design and characterization of DENORMS (Designs for Noise‐Reducing Materials and Structures) cell‐based acoustic metamaterial developed using a 3D printing technique. The metamaterial's acoustic absorption properties were investigated through experimental testing and numerical simulations. The experimental testing of the acoustic metamaterial was conducted in an impedance tube using a two‐microphone method. The numerical simulations were carried out using a thermoviscous module. The simulations allowed for a deeper understanding of the influence of geometric parameters on the absorption coefficient, providing valuable insights for optimizing the design. It was observed that upon increasing the spherical diameter while maintaining the same cylindrical diameter and cylindrical length resulted in an increase in the absorption coefficient throughout the frequency range. It was also observed that upon increasing the cylindrical diameter, there was a significant decrement of absorption coefficient, and upon increasing the length of the cylinder, there was a shift of response toward lower frequency. The augmentation in cell count from 9 to 24 led to a rise in the absorption coefficient and a shift of the response toward lower frequencies. The findings highlight the significance of photopolymer 3D printing in tailoring complex geometries for enhanced performance of the acoustic metamaterial. Highlights: Photopolymeric resin used for DENORMS cell‐based acoustic metamaterial.High cleanability and accuracy of digital light processing 3D printing technique.Usage of thermoviscous model for simulation of sound absorption behavior.Use of two microphone impedance tube to determine sound absorption coefficient.Geometric parameters significantly affect the absorption coefficient. [ABSTRACT FROM AUTHOR]

Developing environmentally friendly building materials with low environmental impacts is receiving more attention nowadays to face the global challenges of climate change; building insulation materials made from agricultural waste can be used for their low environmental impact and to generate responsible supplies that utilize natural resources adequately. The study aims to assess a panel made from rice husk using the pulping method. An experimental design established the proportion of rice husk, the percentage of additive (NaOH concentration), boiling time and blending time. Taguchi's method was applied to investigate the effect on density and thermal conductivity; the final panel with optimum conditions was morphologically analyzed using scanning electron microscopy (SEM); the thermal behavior was studied by thermogravimetric analysis (TGA); fire reaction and smoldering behavior were analyzed; and characterization in water absorption and acoustic absorption performances were established. The results show thermal conductivity values between 0.037 and 0.042 W/mK, a smoldering velocity of 3.40 mm/min, and a good acoustic absorption coefficient in octave frequency bands between 125 Hz and 4 kHz greater than 0.7. These characteristics are competitive with other insulating bio-based materials available on the market. This study employed chemicals utilized by other biomaterials for the pulping process and in flame retardants. However, it is important to investigate natural treatments or those with a diminished environmental impact. [ABSTRACT FROM AUTHOR]

Variations of black carbon concentration and its sources identification were studied in Ar-Ramtha District, north of Jordan, using the aetlalometer model AE33. Measurements at six sites showed that the black carbon concentrations almost have the same behavior due to the uniform nature of the region. The average value of the black carbon concentration in the six sites was 1778 ng/m³, 2288 ng/m³, 1605 ng/m³, 1785 ng/m³, 2267 ng/m³, and 2606 ng/m³ respectively. Analysis of the measurements and Angstrom exponents, pre-calibrated in the instrument, revealed the ability of these variations to apportion black carbon from its sources. The largest contribution of black carbon was from fossil fuels at all sites. The absorption coefficients for each wavelength were measured at all sites. For a wavelength of 370 nm, it was discovered that the absorption coefficient had a maximum value of 58. 27Mm-1 while it it was 20.25 Mm-1 at 880 nm. In all sites, the average absorption coefficients reached their highest value at a wavelength of 370 nm, demonstrating the inverse relationship between wavelength and absorption coefficient. [ABSTRACT FROM AUTHOR]

This article comprehensively examines the characteristics of water samples sourced from diverse locations in the Kathmandu Valley, encompassing density, transmittance, absorption coefficient, mass attenuation coefficient, and molecular cross-sectional area (MCA), across varying temperatures. Density variations, within a temperature range of 8 °C to 48 °C, are reported, spanning from 1.17725 to 1.0015 g/cm3. Transmittance increases with wavelength and exhibits temperature-related variations due to differing impurities among sources. The relationship between transmittance and temperature lacks a distinct pattern, influenced by unique source impurities and temperature effects. Moreover, the MCA estimates particles to be approximately 10−24cm2. Additionally, the mass attenuation coefficient consistently decreases with wavelength across all samples. These findings provide a comprehensive insight into the intricate interplay between water properties, impurities, temperature, and radiation interactions in various water sources. [ABSTRACT FROM AUTHOR]

Down-polyethylene film material has been introduced for the first time as an excellent non-frame sound absorber, showing a distinctively outstanding performance. It contains down fiber adjacent to each other without firm connection in between, forming a structure of elastic fiber network. The unique structure has broadband response to sound wave, showing non-synchronous vibration in low and middle frequency and synchronous vibration in middle and high frequency. The broadband resonance in middle and high frequency allows the structure to achieve complete sound absorption in resonance frequency band. Moreover, down-polyethylene film material possesses forced vibration, corresponding sound absorption coefficient has been obtained based on vibration theory. The down-film sound absorption material has the characteristics of light weight, soft, environment-friendly, and has excellent broadband sound absorption performance. [ABSTRACT FROM AUTHOR]

Recycled fibers obtained from pre-textile waste present advantages and challenges in acoustic absorber design. This study examines the potential of incorporating textile waste into acoustic absorption systems, with a focus on pre-used waste, to increase the percentage of recycled fibers in the textile industry using the quantitative method Used to evaluate the efficiency of panels manufactured in different sound frequencies, from up to 2000 Hz, and, in some cases, up to 3000 Hz Observations indicate that surface cleaning products, pneumafil waste a twist, comb bat residue and waste grinders exhibit the highest sound absorption coefficients in and using waste samples In addition, a procedure has been developed to evaluate the sound absorption reduction coefficient, which exposes high correlations with values obtained by other methods Sound contour mapping further confirms the homogeneity of the sample and reveals the effectiveness of specific sound absorption systems, such as air condition station filters, spinning pneumafil waste, and weaving waste (samples 18, 20, 21, and 23). Nevertheless, the study of integration emphasizes the ability to reuse waste fibers for sound insulation that can absorb adequate sound, reduce reflected sound, and offer a promising solution for dealing with noise pollution. A thorough examination of sound contour maps across absorber surfaces is undertaken to account for the material structure of the absorber, ensuring an accurate representation of how sound is absorbed and distributed within the designated area. [ABSTRACT FROM AUTHOR]

Germanium diselenide (GeSe2) has recently emerged as a promising material for high‐performance optoelectronic devices due to its high absorption coefficient, wide direct bandgap, and anisotropic electronic properties. For the future applications, it is necessary to understand the dynamic evolution of carriers with ultrafast response. In this work, the transient absorption spectroscopy measurements are performed to study the anisotropic dynamic evolution of GeSe2 under the polarized photoexcitation. It is find that the dynamics exhibit linear dichroism and show a significant Auger recombination process when the photoexcitation is perpendicular to the b‐axis of GeSe2. Using first‐principle and transition dipole moment calculations, it is confirmed that the more carrier localization at Γ point along the Γ‐X (perpendicular to the b‐axis) and increase the Auger recombination. In addition, the Auger recombination coefficient ≈ 1.1×10−31 cm6 s−1 is determined and demonstrated that the defect‐assisted indirect Auger recombination plays a key role in the carrier relaxation process. Through time‐resolved transient absorption spectra, it is further revealed that the ultrafast dynamical evolution of excited state absorption peaks under polarized photoexcitation. These results have implications for improving the quantum efficiency of high‐field polarization‐sensitive optoelectronics. [ABSTRACT FROM AUTHOR]

The Himalayas and Tibetan Plateau (the HTP), referred to as "the third pole" with an excessive warming rate, exerts strong impacts on the global environment. As one of warming contributors, atmospheric brown carbon (BrC) remains limited scientific understanding in the HTP due to a scarcity of observations. In this study, we present a study of the light‐absorbing properties of methanol‐soluble brown carbon (MeS‐BrC) and water‐soluble brown carbon (WS‐BrC) during 2018–2021. Highly spatiotemporal variations of BrC light absorptions were observed. In the HTP marginal area, elevated BrC absorption coefficients at 365 nm (babs,365) and levoglucosan concentrations were obtained, and MeS‐BrC exhibits approximately 1.3–1.8 times higher absorption compared to WS‐BrC. We determined that BrC light absorptions was largely attributed to biomass burning (29%–35%). BrC can act as a potent warming agent in the HTP marginal area, with high direct solar absorption (25%–47% relative to black carbon). Plain Language Summary: Atmospheric brown carbon (BrC) remains low scientific understanding in the HTP due to a scarcity of observations. Here, we present a plateau‐scale study of the light‐absorbing properties of methanol‐soluble brown carbon (MeS‐BrC) and water‐soluble brown carbon (WS‐BrC) during the period of 2018–2021. This study highlights the contribution of BrC to the HTP warming. Higher BrC light absorption was observed in the HTP marginal area compared with the central HTP. Enhanced radiative absorption effect of WS‐BrC was obtained in the HTP, with an annual average of ∼25% compared with BC in Qinghai Lake and Ngari, and as high as 46.5% in Purang. The results confirmed the importance of BrC from biomass burning in contributing to light‐absorbing aerosols in this region. Key Points: Brown carbon (BrC) can be a strong warming agent in the marginal Himalayas and Tibetan PlateauHighly spatiotemporal variations of plateau‐scale BrC were observedBrC light absorptions was largely attributed to biomass burning [ABSTRACT FROM AUTHOR]

Generation of ultrashort mid-IR pulses spanning from 8.5 to 10.5 μm with high energy (up to 4.5 μJ) was experimentally demonstrated through difference frequency generation in BaGa2GeSe6 crystal pumped by 100-fs 0.95-μm Ti:sapphire laser pulses. Optical damage threshold and two-photon absorption coefficient were determined for this pump pulses. Frequency conversion efficiency reached 0.24% at 1.85 mJ pump pulse energy and was decreased at higher one. Estimations indicate that application of 15 mm in diameter wide-aperture BaGa2GeSe6 sample will allow one to increase pump pulse energy up to ~10 mJ, and to increase the mid-IR pulse energy up to 24 μJ at the same efficiency. [ABSTRACT FROM AUTHOR]

Progesterone (PROG) and estrone (E1) are typical reproductive hormones in dairy cows. Assessing the levels of these hormones in vivo can aid in estrus identification. In the present work, the feasibility of the qualitative and quantitative detection of PROG and E1 using terahertz time-domain spectroscopy (THz-TDS) and metamaterial technology was preliminarily investigated. First, the time domain spectra, frequency domain spectra, and absorption coefficients of PROG and E1 samples were collected and analyzed. A vibration analysis was conducted using density functional theory (DFT). Subsequently, a double-ring (DR) metamaterial structure was designed and simulated using the frequency domain solution algorithm in CST Studio Suite (CST) software. This aimed to ensure that the double resonance peaks of DR were similar to the absorption peaks of PROG and E1. Finally, the response of DR to different concentrations of PROG/E1 was analyzed and quantitatively modeled. The results show that a qualitative analysis can be conducted by comparing the corresponding DR resonance peak changes in PROG and E1 samples at various concentrations. The best R2 for the PROG quantitative model was 0.9872, while for E1, it was 0.9828. This indicates that terahertz spectral–metamaterial technology for the qualitative and quantitative detection of the typical reproductive hormones PROG and E1 in dairy cows is feasible and worthy of in-depth exploration. This study provides a reference for the identification of dairy cow estrus. [ABSTRACT FROM AUTHOR]

This paper investigates the influence of constituent weight ratios on optical and electrical properties, with a particular focus on the intrinsic properties (such as electrical mobility) of ternary organic blends, highlighting the role of a third component. The study explores novel donor:acceptor1:acceptor2 (D:A1:A2) matrix blends with photovoltaic potential, systematically adjusting the ratio of the two acceptors in the mixtures, while keeping constant the donor:acceptor weight ratio (D:A = 1:1.4). Herein, depending on this adjustment, six different samples of 100–400 nm thickness are methodically characterized. Optical analysis demonstrates the spectral complementarity of the component materials and exposes the optimal weight ratio (D:A1:A2 = 1:1:0.4) for the highest optical absorption coefficient. Atomic force microscopy (AFM) analysis reveals improved and superior morphological attributes with the addition of the third component (fullerene). In terms of the electrical mobility of charge carriers, this study finds that the sample in which A1 = A2 has the greatest recorded value [ μ m a x = 1.41 × 10 − 4 cm 2 / (Vs )]. This thorough study on ternary organic blends reveals the crucial relationship between acceptor ratios and the properties of the final blend, highlighting the critical function of the third component in influencing the intrinsic factors such as electrical mobility, offering valuable insights for the optimization of ternary organic solar cells. [ABSTRACT FROM AUTHOR]

The paper investigates the possibility of fabricating a carbon nanotubes (CNT)-modified nanocomposite based on pyrolyzed polyacrylonitrile (PPAN). The layered structure of PPAN ensures the attachment of nanotubes (NT) to the polymer matrix, forming enhanced PPAN/CNT nanocomposites. We synthesized a PPAN/CNT polymer nanocomposite and investigated its mechanical, conductive, and electronic properties. Using the quantum chemical method density functional theory (DFT), we studied an interaction mechanism between PPAN and single-walled carbon nanotubes. We described the structural features and electron energy structure of the obtained systems. We found that the attachment of a CNT to the PPAN matrix increases tensile strength, electrical conductivity, and thermal stability in the complex. The obtained materials were exposed to electromagnetic radiation and the dielectric constant, reflection, transmission, and absorption coefficients were measured. The study demonstrates the possibility of using carbon nanotubes for reinforcing polyacrylonitrile polymer matrix, which can result in the development of an enhanced class of materials possessing the properties of both polymers and CNTs. [ABSTRACT FROM AUTHOR]

This study investigated the aerosol particle properties and light absorption properties of brown carbon (BrC) by utilizing a seven-wavelength aethalometer, and analyzed NH4+, NO3−, SO42−, K+, K, organic carbon, elemental carbon, levoglucosan, and mannosan in PM2.5. The research was conducted in a rural area of Jeonnam, South Korea, during the winter season. In addition, the dithiothreitol assay-oxidative potential normalized to 9,10-phenanthrenequinone (QDTT-OP) was investigated throughout the study period. The absorption coefficient was found to be 2.6 to 5.6 times higher at 370 nm compared to 880 nm, suggesting the presence of light-absorbing substances in addition to black carbon (BC) particles. The estimated absorption coefficient of BrC370 was 29.9% of the total light absorption coefficient at 370 nm. Furthermore, BrC370 exhibited a strong affinity with levoglucosan while showing a weak correlation with K+, confirming the suitability of levoglucosan as a tracer for biomass burning. The QDTT-OP was 5.3 nM m−3, and highly correlated with the carbonaceous components levoglucosan and mannosan, suggesting a relatively high contribution of biomass combustion emissions to oxidative potential. Further research should be conducted to assess the health risks associated with future PM2.5 exposure related to biomass burning in the atmosphere. [ABSTRACT FROM AUTHOR]

Solar cells comprising earth‐abundant and non‐toxic elements with applicable bandgaps and high absorption coefficients have attracted considerable interest over the past several decades and are important devices for addressing the future demand for clean and renewable energy. Antimony sulfide (Sb2S3) crystal material effectively meets these requirements owing to its suitable bandgap, high absorption coefficient, high electron and hole mobilities, earth abundance, and excellent stability. Solution‐processed Sb2S3 films are essential to facilitate the fabrication of low‐cost, large‐scale, and high‐efficiency photovoltaic devices, but suffer from several shortcomings of large intrinsic defects, high interfacial barrier, and atomic mismatch, uncontrollable film thickness, and crystal orientation. In this review, a systematic overview of the fundamental properties of solution‐processed Sb2S3 materials is presented, and then interface engineering, defect passivation and control strategies, crystal orientation and modulation methods, device structure, and the performance of Sb2S3 solar cells are focused, highlighting the primary advancements and major challenges based on this technology. Finally, several creative perspectives and constructive innovation strategies for future research on Sb2S3 photovoltaic devices are provided, indicating a roadmap for the practical application of other inorganic semiconductor heterojunction thin film solar cells. [ABSTRACT FROM AUTHOR]

This study investigates the alterations in structural, electronic, and optical characteristics of ZnSe1−x Inx (x = 0%, 12.5%, 25%) employing the framework of density functional theory (DFT), utilizing generalized gradient approximation (GGA) in conjunction with the full‐potential linearized augmented plane wave (FP‐LAPW) approach. The findings reveal that pure ZnSe exhibits a direct bandgap of 1.79 eV at the Γ point, which reduces to 0 eV upon doping with Indium, indicating a transition to metallic characteristics. This change is attributed to the predominant involvement of the d‐orbital of Zn, s‐orbital of Se, and p‐orbitals of Indium in the valence band of ZnSe1−x Inx materials. Conversely, the s‐orbital of Zn predominantly contributes to the conduction band of undoped ZnSe, whereas the d‐orbitals of Indium play a significant role in the conduction band of ZnSe1−x Inx (x = 0%, 12.5%, 25%). Moreover, the study computes other optical parameters, including reflectivity, electron energy loss spectrum, extinction coefficient, refractive index, and absorption coefficient, as functions of photon energy. A notable observation is the considerable rise in the zero‐frequency dielectric constant, ε1(0), which increases from 5.0 in pure ZnSe to 40.0 and 50.0 in Indium‐doped ZnSe, highlighting a significant alteration in electronic properties. Furthermore, optical analyses demonstrate an expansion in the absorption coefficient spectrum, which extends from photon energies of 2.0 eV in pristine ZnSe to begin at 0 eV in Indium‐doped variants, indicating a broadening of the material's capacity to absorb light across a wider spectrum of photon energies. This expansion infers improved light absorption potential, which could be particularly beneficial for the fabrication of light‐emitting modules and solar energy converters. These insights underline the considerable influence that Indium incorporation exerts on the band architecture and optical responses of ZnSe, offering critical directions for the advancement of optoelectronic devices. [ABSTRACT FROM AUTHOR]

We prepared ultrafine MnCo 2 O 4 particles using a facile sol–gel autocombustion method. The structural and vibrational characterizations confirmed the formation of a pure cubic spinel phase in as-synthesized MnCo 2 O 4 particles. The surface morphology analyses revealed the porous structure with an average particle size of 5 nm and uniform distribution of manganese (Mn), cobalt (Co), and oxygen (O) in the particles. We observed the presence of multiple valence states of Mn and Co, occupying both tetrahedral and octahedral sites, enhancing our insight into the material's electronic properties and structural configuration. Our magnetization studies unveiled a Curie Temperature (T C) of 185 K with ferrimagnetic ordering below T C , resulting in substantial magnetization (9.8 emu/g) and coercivity (3.46 kOe) at 2 K and weak magnetic behavior above T C. This is attributed to the finite size and surface effects. Furthermore, the incorporation of MnCo 2 O 4 nanoparticles and graphene oxide into a polyurethane foam matrix resulted in an excellent sound absorption coefficient of 90 % at 2000 Hz. This outstanding acoustic performance underscores the versatile applications of MnCo 2 O 4 nanoparticles in diverse noise mitigation applications. [Display omitted] [ABSTRACT FROM AUTHOR]

The incidence of electromagnetic H-wave on the thin metal layer at the angle of theta is considered, taking into account the dependence of the specularity coefficients on the surfaces of the thin layer q1 and q2 on the angle of incidence of electrons. The behavior of reflection, transmission and absorption coefficients depending on the thickness of the thin layer is analyzed. The obtained results are compared with experimental data. [ABSTRACT FROM AUTHOR]

In this study, titanium dioxide (TiO2) nanoparticles are combined with a mixture of polymers (polyvinylalcohol PVA, polyethylene-glycol PEG and polyvinylpyrrolidone PVP). Titanium dioxide (TiO2) NPs was formulation by sol-gel process, nanocomposites were prepared with concentration (1, 5, 10, 15, 20 and 25 wt%). TiO2 NPs after subjecting them to a calcination process at a temperature of about 400 °C and 700 °C and polymer blend of different concentrations (PVA various wt%, PEG constant wt% and PVP constant wt%). A UV-Vis spectrometer was used to determine the optical constants of the prepared-samples. Absorption coefficient, extinction coefficient, refractive-index and optical energy-gap were calculated, it was noticing of absorption coefficient values in calcination 400 °C for 25 wt% TiO2 NPs higher than that of other samples. The refractive index of TiO2 at 700 °C is higher than that of 400 °C due to the different crystalline structure of rutile. The optical energy band gap was determined and it was discovered to decrease from 5.16 eV for (1 wt% TiO2) blended with (PVA 84 wt%, PEG 10 wt% and PVP 5 wt%) up to 3.51 eV (25 wt% TiO2) with concentrations of (PVA 60 wt%, PEG 10 wt% and PVP 5 wt%) as matrix. At a higher calcination temperature of 700 °C, TiO2 transitions from the anatase phase to the rutile phase, this change in crystal structure has a significant effect on the value optical dielectric constant real part (εr) which is (16.06). The findings have important ramifications for possible uses these nanocomposites to enable reuse of the photocatalysts, thus extending their useful life. [ABSTRACT FROM AUTHOR]

This paper delves into the depolarization phenomenon of materials using the integral equation method and Mueller matrix method. In the integral equation method, it is observed that depolarization trends with roughness are similar at different wavelengths, but numerical differences exist. The results are well-supported by both theory and experiments. Specifically, at 1064 nm wavelength, materials exhibit smaller depolarization peaks, smoother trends, and right-shifted peaks compared to 633 nm. Additionally, the polarization characteristics of materials may change with varying incident polarization states. The Mueller matrix method investigates the depolarization trend with varying incident angles and different roughness levels. It reveals a gradual increase in depolarization with the incident angle until 60°, followed by a rapid rise, reaching a peak around 80°. Moreover, materials with higher absorption coefficients exhibit stronger depolarization effects. Overall, this research uncovers the impact of absorption and scattering on the polarization properties of materials, providing valuable insights for future studies in polarization recognition. [ABSTRACT FROM AUTHOR]

In the presented work, we propose a systematic investigation of the electronic and optical properties of MnGa2Se4 by combining the spectroscopic ellipsometry carried out at room temperature in the spectral range of 1–4 eV and density functional theory (DFT) calculations. Ellipsometric measurements were collected at an incidence angle between 60° and 75° with a 5° step. The optical direct gap energies of MnGa2Se4 were estimated from the linear extrapolation of the absorption coefficients that were verified by band structure calculation. DFT calculation of the imaginary part ɛ shows that first critical point occurs at 2.46 eV and represents the direct optical transition at Γ point. The total magnetic moment of compound is 3.38 mB. The major contribution in total magnetic moment is due to 3d state of Mn atoms. [ABSTRACT FROM AUTHOR]