Refractive Index Values Research Articles

First principles insights into Cs2XAgCl6 (X= Sc, Y) compounds for energy harvesting applications

Herein, the investigation is presented to analyze the structural, electronic, optical, and thermoelectric features of Cs2XAgCl6 (X= Sc, Y) by applying the first principles approach. The confirmation of the stable structure of both compounds is reinforced by the negative values of formation enthalpies. The electronic band gaps (Eg) of 3.78/4.86 eV are computed for Cs2ScAgCl6 /Cs2YAgCl6 through Tran-Blaha modified Becke-Johnson (TBmBJ) potential, correspondingly. The tolerance factor(τ) is found as 0.9 for Cs2ScAgCl6 and 1.0 for Cs2YAgCl6 which confirmed the stable cubic nature of both compounds. Optical factors like dielectric-function ε(ω), absorption coefficient α(ω), and others related parameters are analyzed within 0 to 10 eV of energy span. Both compounds demonstrated high absorption in the ultraviolet region, rendering them as well-suited materials for photovoltaic applications. The calculated values of refractive index for Cs2ScAgCl6 and Cs2YAgCl6 indicated super-luminescent characteristics in the ultraviolet region. For thermoelectric (TE) features, electrical conductivity (σ/τ), figure of merit (ZT), power factor (PF), thermal conductivity (k/τ), and Seebeck coefficient (S) are calculated using the BoltzTraP code. According to the findings, both materials are advocated as promising candidates for thermoelectric and optoelectronic applications.

Physicochemical and Functional Properties of Edible Dung Beetle Larvae (Scarabaeus satyrus) Flours and Oils and their Significance in Human Nutrition

The potential of edible insects in alleviating the nutritional challenges facing humans has led to an increased interest in their utilization. Edible insects contain substantial amounts of protein and fats, which are very important macronutrients that confer useful functional and physicochemical properties to foods. However, the functional properties of these nutrients have not been given sufficient attention, limiting their use as ingredients in diets and food products. Processing of insects converts them into an ingredient that can be added to various foods, improving their acceptability in terms of flavor, taste, and nutritional content. Popular processing methods for edible insects include frying, boiling, oven drying, roasting, smoking, and toasting. These thermal treatments reduce the insect water content, enabling them to be milled into powders. This study set out to investigate the fatty acid profile, protein digestibility, and physicochemical and functional properties of powders and oils of edible dung beetle (Scarabaeus satyrus). The dung larvae were collected from three counties in Western Kenya. They were cleaned and subjected to drying and milling, then analyzed. Results indicated that protein digestibility ranged between 64.27-70.03%. The dominant unsaturated fatty acid was Oleic (45.71±2.45%), while the main saturated fatty acid was Lauric (45.43 ±0.8%). The saponification value of the oils ranged between 127.94 -130.17 mgKOH/g oil, Acid value (41.96-44.11 mg KOH/g oil), peroxide value (4.23-3.8 Meq.thio / kg sample), refractive index (1.41-1.44/25ºC) and Iodine value (77.89-88.02 g I/100g). Functional properties of the powders showed high lipophilic (332.45±19.73%) and moderate (1.11±0.14 ml/g) hygroscopic tendencies in toasted samples from Bungoma and Siaya Counties, respectively. Emulsifying capacity varied between 80.85%-82.53%, while emulsifying stability ranged from 80.85%-81.33%. These findings show that the edible Scarabaeus satyrus can provide unsaturated fatty acids and can be a good ingredient in foods as an alternative to conventional cuisines

Chemical Composition and Optical Properties of Secondary Organic Aerosol from Photooxidation of Volatile Organic Compound Mixtures.

The chemical and optical properties of secondary organic aerosols (SOA) have been widely studied through environmental chamber experiments, and some of the results have been parametrized in atmospheric models to help understand their radiative effects and climate influence. While most chamber studies investigate the aerosol formed from a single volatile organic compound (VOC), the potential interactions between reactive intermediates derived from VOC mixtures are not well understood. In this study, we investigated the SOA formed from pure and mixtures of anthropogenic (phenol and 1-methylnaphthalene) and/or biogenic (longifolene) VOCs using continuous-flow, high-NOx photooxidation chamber experiments to better mimic ambient conditions. SOA optical properties, including single scattering albedo (SSA), mass absorption coefficient (MAC), and refractive index (RI) at 375 nm, and chemical composition, including the formation of oxygenated organic compounds, organic-nitrogen compounds (including organonitrates and nitro-organics), and the molecular structure of the major chromophores, were explored. Additionally, the imaginary refractive index values of SOA in the multi-VOC system were predicted using a linear-combination assumption and compared with the measured values. When two VOCs were oxidized simultaneously, we found evidence for changes in SOA chemical composition compared to SOA formed from single-VOC systems, and this change led to nonlinear effects on SOA optical properties. The nonlinear effects were found to vary between different systems.

Investigations on Chemically Synthesized Pure and Doped Manganese Dioxide Nanoparticles for Dye Removal and Photocatalytic Applications.

Pure and Mg2+, Ni2+, Cd2+ doped MnO2 nanoparticles were synthesized by chemical co-precipitation method. These samples were characterised by PXRD, SEM, EDX, FTIR, UV-Vis-NIR, PL, Antibacterial, Cyclic Voltammetry, Dye Degradation and Photocatalytic studies. From the powder XRD studies, the crystallite size of the particle was calculated using Scherer formula and found that the synthesized nanoparticles were in the range from 10 to 12nm. The morphology of all the synthesized samples was viewed from SEM micrograph. The composition and purity of the samples were identified from EDX studies. In FTIR spectra metal-oxygen stretching and bending modes of vibrations were observed. From the absorption spectra of UV-Vis optical analysis values of absorption coefficient, extinction coefficient, refractive index, real and imaginary part of optical dielectric constant and optical conductivity were compared. The band gap energy obtained from Tauc's plot varies from 1.21 to 1.51eV exhibits semiconducting behaviour of all the synthesized samples. Investigations on photoluminecsence spectrum reveals blue shift in wavelength for doped nanooxides compared to pure MnO2. Antimicrobial activity of synthesised samples against gram positive and gram negative bacteria was determined. The obtained results reveal very high bacterial resistance in Cd2+ doped MnO2 nanoparticles with higher activity towards bacterial resistance compared to standard drug. The specific capacitance values were determined from Cyclic Voltammetry studies. Using the batch method of dye removing technique the percentage of malachite green dye removal was calculated. Also the photocatalytic efficiency of all the synthesized MnO2 samples in removing malachite green dye was studied by exposing to sunlight for different dosage and contact time. Ni2+ doped MnO2 shows relatively higher % of dye degradation capacity about 93% for 0.1g of dosage of photocatalysts.

Amelioration of obesity induction by a high-fat diet and related inflammation by Phasa fish (Setipinna phasa) oil in BALB/c mice.

We have extracted and characterized Phasa fish (Setipinna phasa) oil for the first time to evaluate the anti-obesity and related anti-inflammatory effects on obese mice. Inbred male albino BALB/c mice were segregated into three categories: control (C), Obese control group (OC), and Phasa fish oil treated group (TX). To establish the potentiality of Setipinna phasa oil for its anti-obesity and anti-inflammatory properties, it was extracted and characterized using GC-MS method. To evaluate the anti-obesity effect, different parameters were considered, such as body weight, lipid composition, obesity, and obesity associated inflammation. The physicochemical characteristics of Phasa fish oil revealed that the oil quality was good because acid value, peroxide value, p-anisidine value, Totox value, refractive index, and saponification value were within the standard value range. The GC-MS study explored the presence of fatty acids beneficial to health such as Hexadec-9-enoic acid; Octadec-11-enoic acid; EPA, DHA, Methyl Linolenate, etc. The application of Setipinna phasa oil on the treated mice group acutely lowered body weight and serum lipid profile compared to the obese group. In connection with this, leptin, FAS, and pro-inflammatory cytokines TNF-α genes expression were downregulated in the treated group compared to the obese group. The Phasa oil treated group had an elevated expression of PPAR-α, adiponectin, LPL gene, and anti-inflammatory markers IL-10 and IL-1Ra compared to the obese group. This study suggests that Phasa fish oil, enriched with essential fatty acid, might be used as an anti-obesity and anti-inflammatory supplement.

Optical and electrical analysis of polyethylene oxide/disodium hexachloroplatinate complex composite films

AbstractThe present study reports the synthesis of composite films comprising PEO/Na2PtCl6 complex and their deposition onto fused silica substrates via the dip‐coating method. Chemical, crystallographic, and thermal characterizations are carried out to confirm the incorporation of Na2PtCl6 and PEO matrix into the films. The transmittance of the PEO film is initially high and decreases subsquently with an increase in Na2PtCl6 content. The optical band‐gap energy of the composite films decreases exponentially from 4.62 to 3.79 eV with the increase in Na2PtCl6 content. Furthermore, in the normal dispersion region, the refractive index of the PEO film decreases from 2.00 to 1.670 as the wavelength increases from 400 to 700 nm. The refractive index values increase with an increase in the concentration of Na2PtCl6 in the PEO film up to 8 wt.%. The incorporation of Na2PtCl6 into the PEO matrix increases the electrical conductivity because of the combined enhancement of the PEO conductivity and increase i Na2PtCl6. These findings suggest that PEO/Na2PtCl6 complex composite films have potential applications in UV‐shielding and optoelectronic devices.

Effect of Nd substitution on electronic, thermoelectric, and optical response of WO3

The properties of Nd-doped WO3 thin films are studied to assess their suitability for photovoltaic and optoelectronic applications. The simulations on pristine and Nd-doped WO3 were performed using Tran Blaha modified Becke-Johnson approximation to explore the various properties, whereas the spin coating technique was employed to synthesize thin films. X-ray diffraction analysis revealed the crystalline cubic structure in all synthesized thin films. The morphology contains uniform rod-like features and the width of these were enhanced in doped composition. The projected density of states demonstrated the major prominent contributions of W-d in conduction and O-p in the valence band while Nd-f orbital plays a major contribution in doped compositions. Thermoelectric parameters were found to change significantly with Nd incorporation in WO3. The highest refractive index and real epsilon values were recorded at the higher energy regimes approximately 2.96 and 8.61, respectively, for compositions containing maximum dopant content. The optical conductivity and absorption coefficient showed an enhanced trend in doped composition which is considered favourable for improved optoelectronic and photovoltaic applications. The experimental band gap of WO3 was calculated as 2.03 eV and found to decrease with increment of Nd doping concentration.

Determination of solvation parameter model compound descriptors by gas chromatography

The solvation parameter model uses five system independent descriptors to characterize compound properties defined as excess molar refraction, E, dipolarity/polarizability, S, hydrogen-bond acidity, A, hydrogen-bond basicity, B, and the gas-liquid partition constant at 25 °C on n-hexadecane, L, to model transfer properties in gas-condensed phase biphasic systems. The E descriptor for compounds liquid at 20 °C is available by calculation using a refractive index value while E for solid compounds at 20 °C and the S, A, B, and L descriptors are determined by experiment. As a single-technique approach, it is shown that with up to 20 retention factor measurements on four columns comprising a poly(siloxane) containing methyloctyl or dimethyldiphenylsiloxane monomers (SPB-Octyl or HP-5), a poly(siloxane) containing methyltrifluoropropylsiloxane monomers (Rtx-OPP or DB-210), a poly(siloxane) containing bis(cyanopropylsiloxane) monomers (HP-88 or SGE BPX-90), and a poly(ethylene glycol) stationary phase (DB-WAXetr or HP-INNOWAX) are suitable for assigning the S, A, and L descriptors. Using the descriptors in the updated WSU compound descriptor database as target values the average absolute error in the descriptor assignments for 52 varied compounds in the temperature range 60–140 °C was 0.072 for E, 0.016 for S, 0.008 for A, and 0.022 for L corresponding to 30 %, 3.5 %, and 0.6 % as a relative average absolute error for E, S, and L, respectively. For the higher temperature range of 160–240 °C and 34 varied compounds that are liquid at 20 °C the average absolute error for the S, A and L descriptors was 0.026, 0.020, and 0.031, respectively, with the largest relative average absolute error for S of 3.2 % (< 1 % for the L descriptor). For 35 varied compounds that are solid at 20 °C the relative absolute error for the E, S, A, and L descriptors in the higher temperature range was 0.068, 0.035, 0.020, and 0.020, respectively, with a relative average absolute error for E (6.5 %), S (3.5 %) and L (0.88 %). The S, A, and L descriptor can be accurately assigned on the four-column system over a wide temperature range. The E descriptor for solid compounds at 20 °C exhibits greater variability than desirable. The B descriptor cannot be assigned by the four-column system, which lack hydrogen-bond acid functional groups, and is only poorly assigned on the weak hydrogen-bond acid ionic liquid column SLB-IL100.

Investigation of TiO2 replacement alternatives for water-based paints using styrene butyl acrylate

Purpose Titanium dioxide (TiO2) has high opacity, high brightness and whiteness, owing to its high refractive index value. It is mainly used in the coating industry and continuous efforts have been made to replace some of the TiO2 in paint with new pigments. This study aims to replace part of TiO2 pigment with various percentages of BaSO4, CaCO3 and kaolin in styrene butyl acrylate-based paint formulations, without changing the properties of paints using only titanium dioxide. Design/methodology/approach To determine the optimum use rate of new pigment mixing, opacity, gloss, scrub resistance and weather resistance properties have been investigated in the water-based paint formulation. The morphological properties of these samples were examined by scanning electron microscopy analysis. Findings In the total color change (ΔE) measurements, it was observed that the sample coded 85Ti/15Ba produced extremely similar results to the situation when TiO2 was used alone. It was seen that the best results were obtained when 85Ti/15Ba was used instead of TiO2. Originality/value Comparison research on the impact of replacing TiO2 with BaSO4, CaCO3 and kaolin on the performance characteristics of water-based styrene butyl acrylate-based paint formulations has not been done in the literature, according to the literature search.

Application of Metal Oxide in Litho-Vanadium Glasses Containing Non-Magnetic Metal Ions: Physical and Optical Properties Analysis

Sodium-modified litho-vanadium glasses containing non-magnetic Aluminium ions of composition 50Li2CO3 - (30-X) Na2 CO3- 20V2O5 -xAl2O3 (30 ≤ x ≥ 5) (LNVA) glasses were prepared by melt quenching technique. The density of the glass samples was measured and found to increase with the Aluminium content of the glass matrix. The measured values of refractive index and polaron radius of the glass network show opposite behaviour with an increase of Aluminium content. Through band gap energy and refractive index, Oxide ion polarizability and electronic polarizability were determined by using the Lorentz-Lorenz equation. The value of Oxide ion polarizability and electronic polarizability is found to be decreased with decreasing band gap energy and increasing refractive index. The value of optical basicity was measured using electronic polarizability and is found to be decreased with decreasing inter-nuclear distance. The band gap energy values of the glass network were found to decrease from 3.241 to 2.134 eV. The metallisation criterion of the glass material was calculated and found to decrease with Aluminium content.

Synthesis, characterization of Schiff base and its metal complexes and investigation of their electronic and photonic properties

A novel Schiff base (L) and its Pd(II) and Pt(II) complexes were synthesized. The Schiff base was prepared by condensation of 6-tert-butyl 3-ethyl 2-amino-4,5-dihydrothieno[2,3-c]pyridine-3,6(7H)-dicarboxylate with 2,3,4-trimethoxybenzaldehyde. The ligand and its metal complexes were characterized via spectroscopic data i.e. proton and carbon NMR, electronic spectra, FT-IR, LC-MS, as well as melting point, micro analysis, magnetic measurement, molar conductance, and thermogravimetric analysis. The ligand acted as a bidentate molecule coordinating through NO heteroatoms to Pd(II) and Pt(II) metal ions. The geometric structures of Pd(II) and Pt(II) complexes were determined as square-planar. Electronic and photonics properties of metal(II) complexes were investigated under different conditions. Although the optical band gap and refractive index values of the ligand are close to the limit values of the semiconductor, it appears to be an ideal material especially for the semiconductor-insulator region of electronic and optoelectronic devices.

CuO thin films deposited by the dip-coating method as acetone vapor sensors: Effect of their thickness and precursor solution molarity

The superficial morphology and porosity of metal oxide films play an important role in their sensing response to the presence of organic vapors. For films deposited from precursor solutions, both can be modified by varying the solution's molarity and thickness; however, their effect on the film's sensitivity has been scarcely studied in p-type materials. In this work, CuO p-type nanostructured films on glass substrates were obtained from three precursor solutions at different molarities. The films were deposited by dip-coating, varying the coats to obtain thicknesses in the 100–1700 nm wide range. Scanning electron microscopy images show surfaces with higher porous presence as the film's thickness and precursor solution molarity increase. The CuO films were tested as acetone-vapor sensors in a wide concentration range from 1 to 2000 ppm at a sample temperature Ts = 300 °C. Their sensitivity (S) grows as the film thickness increases, regardless of the solution molarity, associated with a higher porosity, calculated from refractive index values. The highest response is obtained for CuO thickest film (τ = 1670 nm) deposited from the solution at the highest molarity. S values of 1.3, 3.4, 4.75, and 7.4 are obtained at 1, 100, 300, and 2000 ppm acetone-vapor concentrations, respectively. These S values are inside the reported ones using more sophisticated techniques and processes.

Growth mechanism, structure, stoichiometry and optical properties of electrochemically grown iron selenide and ferroselite thin films

In this present work, FeSe and FeSe2 thin films were deposited on ITO substrate at different electrolytic bath temperatures at 30 °C and 70 °C by using electrodeposition method. The growth mechanism was investigated via cyclic voltammetry with the potential window was found to be −1600 to 1600 mV versus SCE and the formation of well adherent film was found to be higher bath temperature. XRD result shows the deposited FeSe and FeSe2 films found to exhibit stoichiometric wurtzite and orthorhombic phases respectively. The microscopic observation shows, the uniform particle growth of FeSe and FeSe2 was found to be higher electrolytic bath temperature at 70 °C. The EDX analysis shows the deposited FeSe and FeSe2 films at higher temperature elemental is stoichiometric ratio. The determined bandgap values for FeSe (1.26 eV) and FeSe2 (1.07 eV) deposited at 70 °C. Also, we observed that the refractive indices (n) values was increased for the film deposited from 30 °C to 70 °C resulting, the estimated refractive indices (n) for FeSe and FeSe2 are 3.16 and 3.45 respectively. Furthermore the most significant optical parameters extinction coefficient (k), optical conductivity (σoptical), real (Ɛ1) and imaginary (Ɛ1) dielectric constants and dissipation factor (tan δ) are determined in order to investigate their usefulness in photovoltaic applications.

Effect of Zn doping on optical properties and electrical conductivity-mechanism of Sb-Ge-Se chalcogenide glassy systems

The present communication inspects the impact of zinc doping on the s optical, and electrical characteristics of bulk glassy samples made up of xZn-(0.1-x)Sb-0.2Ge-0.7Se (x = 0.01, 0.02, 0.03, 0.05). The X-ray diffraction patterns confirm that the samples are amorphous. In addition to various optical constants, the linear refractive index, and skin depth have been determined. The decreases in band gap energy values from 1.62 eV to 1.56 eV may be attributed to the rise in Unbach energy values from 0.15 eV to 0.32 eV. The obtained value of refractive indices also increases from 2.91 to 2.95 with the rising Zn content. By using the paradigm of Jonscher's universal power law and the Almond-West formalism, the underlying mechanisms of AC conductivity have been investigated. The AC conductivity increases with temperature and displays semiconducting characteristics. As the power-law exponent (s) reduces with increasing temperature, the correlated barrier hopping model is used to explain the AC conduction mechanism. DC conduction mechanism is described by Mott's and Greaves's variable range hopping model. The anticipated values of tiny polaron hopping energy (Whop) and hopping distance (Rhop) shed light on the increasing trend of DC conductivity with increased Zn concentration.

High Refractive Index Carbonized Polymer Dots Acting as Light Scattering Units in Nanocomposites for Full‐Screen Light Guide Plate

AbstractThe full‐screen mobile phone can be fabricated by integrating the camera beneath the screen, which needs the nanocomposite light guide plate (nano‐LGP) with exceptional transparency and light‐guiding properties simultaneously. Choosing an appropriate nanoparticle with a high refractive index and exceptional compatibility within the polymer matrix is crucial for producing the nano‐LGP. In this study, the high refractive index carbonized polymer dots (HRI‐CPDs) are synthesized through the solvothermal treatment, achieving a refractive index value of 1.7220 at 450 nm. Subsequently, the modified HRI‐CPDs (mHRI‐CPDs)/polymethyl methacrylate (PMMA) nanocomposites are fabricated by copolymerizing the mHRI‐CPDs with methyl methacrylate . Due to the high visible light transmittance and Rayleigh scattering characteristics when light passes through the nanocomposites, this kind of nanocomposites is suitable for serving as nano‐LGPs. The potential of carbonized polymer dots as light‐scattering unit is originally explored to improve surface illuminance and uniformity of nano‐LGPs. The best‐performing 4.3‐inch LGP with 1.0 wt.% doping content shows 15.8 times higher surface illuminance and 2.1 times higher uniformity than pure PMMA. This new type of LGP based on mHRI‐CPDs/PMMA nanocomposite holds tremendous promise in conjunction with advanced liquid crystal display technology.

Effects of cultivar, harvesting time and isolation techniques on the essential oil compositions of some lemon cultivars

&lt;p&gt;In this study, Batem Pınarı, Interdonato, Meyer, and Ak Limon lemon cultivars were studied. Lemon peel's essential oils were obtained by two different methods (hydrodistillation and cold pressing) during four different harvest periods for each cultivar. Essential oil content, density, refractive index, optical activity, and composition were evaluated. The highest essential oil amount was found in the Interdonato cultivar (2.54%) and the lowest in Ak Limon (1.37%). The highest density value was 0.8471 g/mL (Ak Limon) and the lowest was 0.8423 g/mL (Meyer). Essential oil densities obtained by cold pressing were higher than those obtained by hydrodistillation. The highest refractive index values were determined for Batem Pınarı and Meyer (1.4747), and the lowest were determined for Ak Limon (1.4740). The refractive index values obtained by cold pressing were higher than those obtained by hydrodistillation. Optical activity values were found to be highest in Ak Limon and lowest in Batem Pınarı, and higher following hydrodistillation than cold pressing. The essential oil compositions of the samples showed significant differences depending on the cultivar and isolation method. Limonene, the highest component proportionally, composed 76.0%–89.0% of samples. The highest limonene content was determined for Ak Limon (88.7%), and the lowest for Batem Pınarı (76.7%). Limonene content did not change significantly between hydrodistillation (82.2%) and cold press (82.2%) isolation methods. Findings show that there is significant variation in quality parameters of lemon peel essential oils.&lt;/p&gt;

Sequential infiltration of two-photon polymerized 3D photonic crystals for mid-IR spectroscopic applications

Photonic crystals (PhCs) are spatially organized structures with lattice parameters equivalent to the operational wavelength of light. PhCs have been subject to extensive research efforts in the last two decades and are known for controlling light propagation with applications in sensing and time-delayed communication due to the slow-light phenomenon. Despite their exceptional properties, PhCs are difficult to fabricate using planar micromachining techniques due to their periodic structures. Techniques like two-photon stereolithography have been discussed for PhC fabrication in the literature, but the inherent disadvantage of poor refractive index (RI) contrast results in limited application. In this work, we present sequential infiltration synthesis performed on two-photon stereolithographically printed 3D PhCs for infiltration with zinc oxide to increase the RI of 3D PhCs. Finite element analysis was performed over a range of RI contrast values to study the change in photonic bandgap (PBG) with RI contrast. The transmission spectra were recorded on 3D PhCs before and after infiltration to demonstrate the change experimentally. An increase in the PBG width and absorbance is seen postinfiltration due to enhanced RI. This work presents the first, to our knowledge, sequentially infiltrated enhanced 3D PhC fabricated with two-photon stereolithography.

Enhancing saturable absorption in a Au-decorated MoS2/PEDOT:PSS nanocomposite through plasmon resonance and Pauli blocking.

We have effectively demonstrated a technique for substantial alteration of the nonlinear saturable absorption (SA) properties in nanocomposite films (NCF) composed of poly(3,4-ethylenedioxythiophene) doped with poly(4-styrenesulfonate) (PEDOT:PSS) and molybdenum disulfide (MoS2) decorated with gold nanoparticles (AuNPs). This control is achieved by adjusting the AuNP concentration on the MoS2 surface and varying the input pulse energy of the laser. The simple drop-casting method is used to create the nanocomposite films (NCFs) on a glass substrate with different amounts of Au-decorated MoS2. The Kramers-Kronig equations are employed for determining the refractive index and extinction coefficient values of the resulting NCFs. Nonlinear investigations reveal that adding Au-decorated MoS2 to pure PEDOT:PSS alters its optical nonlinearity. Surface plasmon resonance and Pauli blocking have been observed in Au-decorated MoS2/PEDOT:PSS NCFs. This increases NCF's saturable absorption. An open aperture Z-scan method is utilized to study nonlinear optics, with excitation achieved using a nanosecond (ns) pulsed laser operating at a 532 nm wavelength. The findings reveal the noteworthy saturable absorption characteristics of the NCFs.

Electrosynthesis and Characterizations of Aluminum Silver Selenide (Alagse2), Thin Films for Possible Device Applications

The semiconductor thin films of Aluminum Silver selenide (AlAgSe2) have been successfully deposited onto FTO glass substrate using electrodeposition method. AgNO3, AlCl3.6H2O and Selenium powder were the precursors used for sources of Ag, Al and Se ions respectively. Prototype of the films were again made and subjected to annealing at temperature of 150°C for 5 minutes to remove the element of moisture content in the as deposited films. The properties of the films such as optical, structural and compositional were investigated using UV-VIS Spectrophotometry, X-ray diffractometry and Rutherford Backscattering Spectroscopy (RBS) analysis respectively to determine the possible areas of applications of the films. Optical analysis revealed that the films have high absorbance in the UV region but decreased in the visible and near infrared regions. The increase in the concentration of selenide ions however decrease the absorbance of the films but annealing tends to increases the absorbance. The films also exhibited very high values of refractive index with minimum value in the order of 2.0 for both the annealed and as deposited samples. The bandgap energies of the films were found to be 1.7 eV, 1.8 eV, 2.2 eV, 2.8 eV and 2.9 eV for as deposited, but decreased to the values of 1.5 eV, 1.6 eV, 1.92 eV, 2.15 eV and 2.5 eV after annealing for the films deposited with 0.1 M, 0.2 M, 0.3 M, 0.4 M and 0.5 M Se ions respectively. The structural analysis indicates that AlAgSe2 films are crystalline in nature with most preferential crystalline plane of (112). The RBS compositional analysis showed that the deposited thin films are rich in silver content. These properties exhibited by the deposited thin films of AlAgSe2 are desirable for photovoltaic devices and for many other optical and optoelectronic applications.

Chalcophosphate metasurfaces with multipolar resonances and electro-optic tuning.

We computationally analyze the electro-optic response of metasurfaces consisting of interconnected nanoantennas with multipolar resonances using a chalcophosphate, Sn2P2S6, as the active material. Sn2P2S6 has large electro-optic coefficients and relatively low Curie temperature (<70 °C), allowing for strong changes in the refractive index of the material under moderate electric fields if the temperature can be finely controlled in proximity of the Curie point. Through numerical simulations, we show that metasurfaces designed with this nanostructured material demonstrate a significant shift of multipolar resonances upon biasing, despite moderate refractive-index values of the chalcophosphate and reduced mode localization due to this. The magnetic octupolar resonance of a dense array provides the strongest shift of spectral features upon changes in the refractive index, and we attribute it to the high mode localization of this higher-order multipole. We numerically demonstrate that narrow lattice resonances of collective nature do not provide an advantage in shifting the spectral features because of the nonlocal and delocalized nature of the modes, which are spread in the nanoantenna surrounding rather than confined inside nanoantennas. Both in-plane and out-of-plane biasing of the chalcophosphate crystals are similarly efficient with suitable electrode design, choice of electrode material, and crystal orientation within the nanoantennas. These designs exhibit optical properties similar to those of metasurfaces with isolated nanoantennas in the dense array.