UV Vis NIR Spectrum Research Articles

The probing of local charge with sulfur encapsulated in single-walled carbon nanotubes

In this study, we demonstrated the remarkable sensitivity to electrochemical local charge of sulfur chains encapsulated in small-diameter single-walled carbon nanotubes (S@SWCNTs). To perform micro- and macro-spectroscopic probing, a transparent electrochemical cell was designed in which the charging electrode is formed based on S@SWCNTs. During a short-term electrochemical charging, significant reversible changes were observed in-situ in both Raman and UV–vis-Nir spectra of S@SWCNTs. The optical response was found to depend on the magnitude and sign of the charge, as well as on the duration of the electrochemical charging process at a given potential. The enhanced Raman modes of sulfur chains exhibited a notable linear shift (up to 10 cm-1) accompanied by a redistribution of their intensities. A correlation is identified of the chronoamperometry curve (charging current versus time) and transformations of the Raman spectrum of single-atom sulfur chains. Atomistic simulations allowed to attribute these changes in the Raman spectrum to the softening of the sulfur bonds upon charging. Our findings revealed that the nanotube inhibits the chemical interactions between encapsulated sulfur and local charge sources, thus rendering S@SWCNTs suitable for repeated utilization in local charge analysis.

Improving broadband absorption of carbon dot conjugated melanin via pre-doping strategy as interfacial photothermal evaporator

Photothermal seawater desalination harnesses solar energy to induce heat and expediates seawater evaporation and purification. The desalination efficacy heavily relies on the light absorption capability and microstructure of the solar evaporator. Polydopamine (PDA) represents a typical synthetic melanin with broad spectral absorption characteristics. However, its absorption capacity within the near-infrared (NIR) region is limited, leading to inadequate photothermal conversion efficiency. To overcome this challenge, we adopt a straightforward approach involving the pre-doping of N,S-doped carbon quantum dots (N,S-CQDs) with dopamine through covalent interaction to fabricate CQDs-loaded mesoporous polydopamine (MPDA-8). This strategy effectively reduces the band gap of PDA by fostering additional donor–acceptor pairs and π-stacking structures, thereby broadening the absorption capacity across the UV–Vis-NIR spectrum through nonradiative transitions. The MPDA-8 coated Balsa wood and cellulose evaporator achieved high evaporation rates of 1.82 kg m−2 h−1 and 2.10 kg m−2 h−1, respectively, overcoming the limit of 2D interfacial evaporator. The small pores and fiber channels within the wood, coupled with the hydrophilicity of MPDA-8, facilitates efficient water transportation and reduces evaporation enthalpy. Outdoor evaporation experiments conducted under sunlight corroborated the practical viability of this material. This study introduces a new perspective for advancing synthetic melanins in photothermal applications through the nanoparticle pre-doping strategy.

Thin film synthesis and photovoltaic performance of polypyrrole@cobalt hydroxide composites for solar cells and optoelectronic devices

Mono-nanocomposites (MNCs) comprising polypyrrole (PPy) and cobalt hydroxide nanoparticles (Co(OH)2 NPs) are emerging as highly favorable contenders for applications in solar cells and optoelectronic devices, owing to their distinctive attributes encompassing robust light absorption, elevated conductivity, and commendable chemical stability. This investigation delves into the production of a thin film [PPy@Co(OH)2]MNC utilizing the physical vapor deposition (PVD) method. The structural and morphological characteristics of the [PPy@Co(OH)2]MNC thin film were scrutinized through X-ray diffraction (XRD) and scanning electron microscopy (SEM). Optical properties, namely reflectance (R), absorbance (Abs), and transmittance (T) within the UV–vis–NIR spectrum, were precisely gauged at room temperature. Time-dependent density functional theory (TD-DFT) calculations and optimizations were conducted to analyze the geometric parameters, while the refractive index dispersion was probed using the single oscillator Wemple-Didomenico (WD) model. Additionally, the energy of a single oscillator and the energy of dispersion were quantified. The [PPy@Co(OH)2]MNC thin film exhibited pronounced light absorption across the UV–vis–NIR spectrum, characterized by a bandgap of 1.6 eV. The Au/[PPy@Co(OH)2]MNC/p-Si/Al heterojunction device demonstrated a power conversion efficiency and fill factor (FF) of 2.6 % and 55.07 %, respectively, under an irradiance of 100 W/cm2. The findings of this investigation underscore the potential of [PPy@Co(OH)2]MNC-based thin films as auspicious candidates for deployment in solar cells and optoelectronic devices.

Investigation on growth, structural, mechanical, linear and nonlinear optical properties of DiLithium Fumarate TetraHydrate single crystal

In this work reports on the growth and characterization of semiorganic NLO single crystal of DiLithium Fumarate TetraHydrate (DLFTH) using a slow evaporation technique. The crystal structure was an orthorhombic crystal system with the centrosymmetric space group Pbcn, as demonstrated by single crystal X-ray diffraction (SCXRD) investigations. The UV–Vis-NIR spectrum is used to derive optical parameters, such as the lower cut off wavelength (277 nm) and optical energy band gap Eg = 4.98 eV. DLFTH crystals belongs to hard material category using Vickers microhardness test. From NLO studies, the nonlinear optical parameters were studied, such as the nonlinear refractive index (n2), absorption coefficient (β) and third order NLO susceptibility (χ3). The crystal has the properties of saturable absorption and self-defocusing nature. Third order NLO susceptibility (χ3) were found to be 4.14384 × 10-10esu. The higher χ3 number is due to the presence of hydrogen bonds between C-H-O and O-H-O atoms. Therefore, we confirm that it’s applicability for optical device applications.

Enhancing luminescence performance via adjusting the doping concentration and boron aluminum ratio in Dy3+ -activated barium-boroaluminosilicate glasses for laser and W-LED applications

A series of barium-boroaluminosilicate [30SiO2-11Al2O3-44B2O3-5BaO-(10-x)K2O-xDy2O3 (with x = 0.25, 0.5, 0.75, 1.0, 1.25, 1.5 mol%)] glasses doped with Dy3+ ions were prepared by the high temperature (melt quenching) method. In the glass matrix, the relationship among structure, luminescence properties, and B/Al ratio was analyzed; also studied are the physical properties of glass and influence of Dy3+ concentration on the luminescence properties. Differential Scanning Calorimeter (DSC) results have shown the glass matrix exhibiting good thermal stability and high resistance to crystallization. FTIR and Raman spectra have confirmed the presence of stretching and bending vibrations of [BO3], [AlO4] and [SiO4] structural units in the prepared glass. The observed UV–Vis–NIR spectra have indicated that the existence of thirteen bands corresponding to the transition Dy3+ ions from 6H15/2 level to different excited levels; the transmittance curves obtained have shown the transmittance up to 91 %. Increase in Dy3+ concentration is found to decrease the optical band gap; the calculated Judd-Oflet parameter is found to follow the trend Ω2＞Ω4＞Ω6. Photoluminescence studies have shown three emission peaks which could be associated to the transitions: 4F9/2 → 6H15/2 (blue light), 4F9/2 → 6H13/2 (yellow light), and 4F9/2 → 6H11/2 (red light); the maximum intensity obtained for the glass with x = 0.75 mol%, with spacing between Dy3+ ions being 1.9137 Å; and the decay curve could be fitted with double exponential function. The CIE results have revealed that the chromaticity coordinates are closer to that of standard white light, and the color temperature located in the region of cold white light.

Novel solar-induced wastewater purification materials originated from ore tailing solid waste

Ore tailings (OT) are solid waste produced as a by-product of the mining industry, posing serious environmental challenges. Ensuring the low-carbon and environmentally friendly development of mineral raw materials, enhancing the reclamation, reuse and recycling rate of raw materials in the full lifecycle, presents a significant challenge. To achieve high-value utilization of OT and solve the problem of clean water supply, a novel solar evaporation wastewater purification material was developed using modified ore tailing/acrylate composite photothermal coating. The photothermal functional modified ore tailings (OT@PDA@CB) were fabricated by grafting carbon black (CB) and polydopamine (PDA) onto the OT surface through the physical adhesion of active chemical groups, synergistically enhancing broadband light absorption ability of OT@PDA@CB/acrylate coating. UV–Vis-NIR spectra showed increased absorption in visible and near-infrared (NIR) light. Surface temperature of OT@PDA@CB/acrylate coating under 1200 W/m−2 illumination increased to 65.6 °C compared with 52.6 °C of OT/acrylate coating due to increased light absorption, resulting in an evaporation rate of 0.89 kg·m−2·h−1 within 1 h. The solar evaporation efficiency for OT@PDA@CB evaporator was 48.3%, which was 192.7% higher than that in blank acrylate sample. The obtained OT@PDA@CB/acrylate composite photothermal coating demonstrated versatile abilities for desalination, heavy-metal purification and organic contaminant removal. This work offers a straightforward approach for high-value utilization of inexpensive mineral solid wastes and green solar-induced wastewater purification technique.

Enhanced anti-cancer potency of sustainably synthesized anisotropic silver nanoparticles as compared with L-asparaginase

Acute lymphoblastic leukemia (ALL), a hematologic cancer that involves the production of abnormal lymphoid precursor cells, primarily affects children aged 2 to 10 years. The bacterial enzyme L-asparaginase produced from Escherichia coli is utilised as first-line therapy, despite the fact that 30 % of patients have a treatment-limiting hypersensitivity reaction. The current study elucidates the biosynthesis of extremely stable, water-dispersible, anisotropic silver nanoparticles (ANI Ag NPs) at room temperature and investigation of its anti-tumor potency in comparison to L-asparaginase. The optical, morphological, compositional, and structural properties of synthesized nanoparticles were evaluated using UV–Vis-NIR spectroscopy, Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectroscopy, and X-ray Diffractometer. The UV–Vis-NIR spectra revealed the typical Surface Plasmon Resonance (SPR) at 423 nm along with additional NIR absorption at 962 nm and 1153 nm, while TEM images show different shapes and sizes of Ag nanoparticles ranging from 6.81 nm to 46 nm, together confirming their anisotropic nature. Further, the MTT assay demonstrated promising anticancer effects of ANI Ag NPs with an IC50 value of ∼7 μg/mL against HuT-78 cells. These sustainable anisotropic silver nanoparticles exhibited approximately four times better cytotoxic ability (at and above 10 μg/mL concentrations) than L-asparaginase against HuT-78 cells (a human T lymphoma cell line). Apoptosis analysis by Wright-Geimsa, Annexin-V, and DAPI staining indicated the role of apoptosis in ANI Ag NPs-mediated cell death. The measurement of NO, and Bcl2 and cleaved caspase-3 levels by colorimetric method and immunoblotting, respectively suggested their involvement in ANI Ag NPs-elicited apoptosis. The findings indicate that the biogenic approach proposed herein holds tremendous promise for the rapid and straightforward design of novel multifunctional nanoparticles for the treatment of T cell malignancies.

Explaining Color Change in Gem-Quality Andradite Garnet

The homomorphic substitution of the garnet group is common in nature. Two rare color-changing andradite garnets are studied in this paper. One color changes from yellowish-green in the presence of daylight to maroon under incandescent light; the other color changes from brownish yellow to brownish red. In this study, conventional gemological instruments, infrared (IR) spectroscopy, ultraviolet–visible–near infrared (UV–Vis–NIR) spectroscopy, Raman spectroscopy, and electron probe microanalysis (EPMA) were used to explore the gemology and coloration mechanisms of color-changing garnets. Experiments revealed that the color-changing gemstones in the study are andradite garnets. There are two transmission windows in the UV–Vis spectrum: the red region (above 650 nm) and the green region (centered at 525 nm). The chemical compositional analysis indicates that the samples are very low in Cr (<1 ppm) and high in Fe2+ (from 2.31 wt.% to 4.66 wt.%). The combined spectra and chemical compositional analysis show that Fe2+ is the main cause of the color change. Based on the IR spectrum (complex water peaks), UV–Vis–NIR spectrum (similar to that of Namibian andradite garnet), and chemical compositional analysis (low Cr content), it is concluded that color-changing andradite may be related to skarn rock genesis.

Microbial contaminated paper substrate: UV–Vis–NIR spectra of model systems

This study aims to study the possibility of distinguishing the UV–Vis–NIR spectra of filamentous fungi on a paper substrate from the background. Model samples of five filamentous fungi were used: Alternaria alternata, Aspergillus niger, Cladosporium herbarum, Penicillium chrysogenum, and Trichoderma atroviride. The model samples were cultivated on paper substrates, and two methods, cross-validation (CV) and principal component analysis (PCA), were utilised to compare their spectra with the reference background spectra. The results of the CV analysis indicated that certain combined spectra sets of Cladosporium herbarum, Penicillium chrysogenum, Trichoderma atroviride, Aspergillus niger, and Alternaria alternata, at specific surface concentrations, exhibited two active components, signifying distinguishable differences from the background spectra. Additionally, the score scatter diagrams derived from PCA revealed clusters of samples, further confirming the distinguishability of the filamentous fungi spectra from the background. However, for Trichoderma atroviride, the scatter diagram demonstrated a relatively large scattering of points, impeding the resolution of spectra with a surface concentration of 2 105 cm−2 due to measurement inaccuracies. Based on the combined results of CV and PCA, the study concluded that the lower threshold of measurability for UV–Vis–NIR spectra varied among the different filamentous fungi. For example, Cladosporium herbarum, Penicillium chrysogenum, and Trichoderma atroviride exhibited a threshold around a surface concentration of 2 106 cm−2, while Aspergillus niger had a threshold around 2 105 cm−2, and Alternaria alternata had a threshold around 2 103 cm−2. In summary, this research provides insights into the distinguishability of filamentous fungi spectra on the paper substrate from background spectra using spectral analysis techniques, offering potential applications in fungal identification and characterisation.

Wideband close perfect meta surface absorber for solar photovoltaic and optical spectrum applications

The leading research challenge is to develop a meta-surface absorber design for optimal performance across ultraviolet, visible, and near-infrared wavelengths. In ongoing research, a meta-surface absorber is being introduced, designed to achieve near-perfect absorption of 99% across the 250–2500 nm UV–Vis-NIR spectrum for both Transverse electric (TE) and Transverse magnetic (TM) polarized waves. The aimed design features a symmetrical resonator pattern, resulting in a polarization-insensitive absorption response. Additionally, the absorption response demonstrates robustness when altering the geometric parameters of the meta-surface unit cell. Precise simulation and modelling of the proposed meta-surface absorber are achieved by Employing a Finite Difference Frequency Domain (FDFD) solver, coupled with the Finite Integration Technique (FIT) and a tetrahedral mesh component. Verification of absorption characteristics is conducted through three frameworks: impedance matching, interference, and an equivalent circuit model. The suggested meta-structure design exhibits a uniform absorption response, as determined through considerations of impedance matching, interference theory, and the equivalent circuit theory. The PCR value is significantly lower than recent studies, reinforcing that the proposed meta-surface primarily serves as an absorber, not a polarization converter. The absorption response of the suggested meta-structure design remains consistent across the range of electromagnetic wave polarization angles from 0 to 90 for both TE and TM waves. Furthermore, the absorption response of the proposed design demonstrates stability up to an incident angle of 70 for electromagnetic waves. The distribution of electric and magnetic fields, along with surface current density on the proposed design, validates the existence of localized, propagating, and cavity surface plasmon resonance. These collectively create anti-parallel current flow, leading to the absorption of incident EM waves. Furthermore, the suggested design achieves a solar energy thermal conversion efficiency of 99% across the operational spectrum at a working temperature of 573 K, substantiating its potential for use as a solar absorber. Thus, this study presents a meta-structure unit cell that addresses the challenge with near-perfect absorption, polarization independence, and angle robustness. Applications include photodetection, thermal mapping, solar harvesting, and photo-trapping.

Synthesis structural optical and mechanical properties of Nb3⁺ doped Zinc Borophosphate glass for radiation shielding application

Abstract The Nb3⁺ doped Zinc Borophosphate glass (30B2O3 +35P2O5+5TiO2+10ZnO+9LiCO3+10 BaCO3+1NbO2) has been synthesized successfully using melt-quenching method. The powder X-ray diffraction (XRD) analysis was used to find the glass nature of Nb3⁺ doped Zinc Borophosphate glass. The functional group of Nb3⁺ doped Zinc Borophosphate glass was recognized using Fourier-transform infrared spectroscopy (FTIR) analyses. Linear optical properties of the Nb3⁺ doped Zinc Borophosphate glass were studied using UV–vis–NIR spectrum in the room temperature. Mechanical behaviour of Nb3⁺ doped Zinc Borophosphate glass was examined through Vicker’s hardness method. The mechanical properties of Nb3⁺ doped Zinc Borophosphate glass was examined with various loads. The emission transitions of Nb3⁺ doped Zinc Borophosphate glass was studied using Photoluminescence analysis. The CIE diagram of the Photoluminescence was examined. Gamma ray shielding parameters such half value layer, mean free path and mass attenuation coefficient of Nb3⁺ doped Zinc Borophosphate glass were studied using Phy-X software.

Visible to near-infrared broadband electrochromic switching of π-extended viologen exhibiting highly efficient photothermal conversion

This study describes a new π-extended viologen molecule (TFBV) characterized by an electron-deficient structure inserted between two pyridinium groups. The single-layered electrochromic devices (ECDs) using TFBV all-in-one ion gel exhibit remarkable transparency under neutral conditions and display strong absorption bands in the visible and near-infrared (NIR) regions. The TFBV ECDs undergo a black coloration at a low operating voltage (−1.4 V), and at higher voltages (>−1.5 V), they display notable absorption in the NIR-II region. The two-electron reduction to neutral TFBV was confirmed through the chemical reduction of TFBV using Na2S, monitored through UV–vis spectra and 1H NMR titrations. The TFBV ECDs demonstrate an impressive color contrast of up to 96 % and a coloration efficiency of 150.18 cm2/C. The ECDs show outstanding kinetic stability through the 2000th cycle and moderate switching stability up to the 10000th cycle, accompanied by fast coloration times. Flexible TFBV ECDs, built on ITO PET, sustain superior performance even during flat and semicircle bending maneuvers, ensuring stability across repeated bending cycles. A uniform color transition is achieved in large-area ECDs of 10 cm × 10 cm. The strong NIR absorption of TFBV ECDs enables the photothermal heater to harvest the heat from the light energy, inducing a temperature rise of 45 °C. Furthermore, these devices perform a photothermal conversion efficiency of 52.5 % during multiple on–off cycles. TFBV ECDs, offering high transparency and intense darkness while blocking UV–Vis-NIR spectra, prove promising candidates for broadband ECDs with integrated photothermal conversion capabilities.

Morphology matters: Investigating the influence of granules and nanofibers on the physicochemical properties of TiO2 for optoelectronic applications

This study investigated the influence of morphology on the physiochemical properties of TiO2, specifically comparing granule-like structures and nanofibers. Both morphologies were fabricated using different methods and characterized comprehensively. After annealing, X-ray diffraction confirmed their crystalline nature with peaks corresponding to the anatase phase of titania. Scanning electron microscopy revealed long nanofibers with diameters ranging from 62 nm to 95 nm, while the granules appeared as spherical or nearly spherical particles with sizes between 43 nm and 59 nm. Energy-dispersive X-ray analysis confirmed the presence of Ti and O in both structures. The Fourier-transform infrared and raman spectra exhibited characteristic bands related to the Ti–O–Ti stretching, vibrational, binding and anatase phase of titania, respectively. Raman peaks' intensity and position were influenced by crystal size, quality, and strain. The nanofibers showed higher raman mode peak intensities due to their larger surface area to volume ratio and high aspect ratio. In UV–Vis–NIR spectra, the nanofibers displayed higher absorption and a narrower bandgap than the granules. Hall Effect measurements indicated that the nanofibers had a higher carrier concentration and conductivity than the granules. Additionally, the nanofibers exhibited hydrophobic behavior with a water contact angle of 95°, while the granules were relatively hydrophilic with a contact angle of 58o. The findings could potentially facilitate the creation of customized TiO2 materials that are better suited for specific optoelectronic devices. This advancement would result in improved overall efficiency and performance across a range of technological uses.

KBi(SeO4)(IO3)Cl: A mixed-anion oxychloride with three types of building units in one structure

A novel mixed-anion oxychloride, KBi(SeO4)(IO3)Cl, has been hydrothermally synthesized and structurally characterized. The compound crystallizes in the monoclinic space group of P21/c with cell parameters of a = 7.8802(2) Å; b = 10.8088(2) Å, c = 10.1364(2) Å, β = 112.849(1)°, V = 795.62(3) Å3, and Z = 4. KBi(SeO4)(IO3)Cl exhibits a three-dimensional tunnel framework that is composed of three types of atomic groups, i.e., tetrahedral SeO4, trigonal pyramidal IO3, and polyhedral BiO6Cl. Both IO3 pyramid and BiO6Cl polyhedron are in strongly acentric coordination due to the influence of I5+ and Bi3+ lone electron pairs. The measurement of UV–vis–NIR spectra for powder KBi(SeO4)(IO3)Cl indicates that the material is a wide band gap semiconductor with Eg = 3.9 eV. Theoretical analysis shows that the electron transition from Bi 6p to O 2p states in the BiO6Cl unit dominates the optical absorption edge. Thermal stability and IR spectrum were also analyzed for the material.

Structural, Morphological, and Optical Properties of Single and Mixed Ni-Co Aluminates Nanoparticles

A series including single and mixed Ni-Co aluminates was obtained using the precursor method, with malic acid as a ligand. The malate precursors (polynuclear coordination compounds) were isolated and characterized by Fourier Transform Infrared (FTIR), Ultraviolet/Visible/Near Infrared (UV–Vis–NIR) spectroscopy, and thermal analysis. The UV–Vis–NIR spectra of the synthesized complex compounds highlighted the presence of Co2+ and Ni2+ in an octahedral environment. The thermal decomposition of these precursors led to Co1−xNixAl2O4 (x = 0, 0.1, 0.25, 0.5, 0.75, 0.9, and 1) spinels. The effect of Ni2+ substitution on the structure, morphology, and optical properties of the obtained oxides was studied with the help of different characterization tools. XRD, FTIR, and Raman spectra evidenced the formation of the spinel phase. The size of the crystallites and the agglomeration degree of the particles decrease when the nickel content increases. The band gap (BG) value is not significantly influenced by the Ni substitution. The fluorescence spectra recorded for all samples show a similar pattern, but different intensities of the emission bands.

Color Origin of Greyish-Purple Tremolite Jade from Sanchahe in Qinghai Province, NW China

Greyish-purple tremolite jade has become well known in the past few years, and the origin of its color has attracted the attention of gemologists. In this study, FT-IR spectra, EPMA, EPR spectra, micro-XRF, UV–Vis–NIR spectra, and LA-ICP-MS in situ mapping were analyzed to investigate the chromophore elements. The study sample was chosen from the Sanchahe mine, Qinghai Province, NW China, which has the typical characteristics of a gradual color change. The FT-IR and EPMA results revealed that the mineral composition of the dark and light greyish-purple regions of the sample are primarily composed of tremolite. UV–Vis–NIR spectra demonstrated that the greyish-purple color is mainly due to strong absorptions at 560 nm and 700 nm and weak absorption at 745 nm in the visible range. The EPR spectra presented ~3400 G six hyperfine lines resulting from the hyperfine interactions of the unpaired electron with the Mn2+ nucleus in the octahedral site. The UV–Vis–NIR and EPR spectra analyses demonstrated that Mn2+ is the origin of the purple color. A comparison of the major elements in the light and dark regions indicated that the chromogenic elements have strong positive correlations with Mn, Cu, and Fe. LA-ICP-MS mapping used to analyze the first transition metals indicated possible positive correlations between the greyish-purple color and the trace chromogenic elements. This suggested that the Mn, Cu, and Fe contents are significantly high in the dark band region. Combining in situ LA-ICP-MS mapping of trace elements, UV–Vis spectra, and EPR analysis results, it was suggested that Mn, Cu, and Fe are the major contributors to the greyish-purple color. This study provides a reference for the specific experimental methods to determine chromophores and the origin of color in tremolite jades.

Near room temperature tunability of thermochromic VO2 thin films prepared via thermal oxidation method, influence of CO2:N2 gas flux ratios

In this study, we have investigated the thermochromic characterizations of VO2 thin films synthesized by the thermal oxidation method. The oxidation process of a DC sputtered metallic vanadium layer on glass substrates, at 450 °C for 1 h, was carried out in the presence of CO2:N2 gases with different flux ratios of 30:70, 40:60, 50:50, 60:40, and 70:30, respectively. Using CO2, as the oxidizing gas, provides an easy control route for obtaining the VO2 phase among various vanadium oxide phases. The layers were characterized by FESEM, XRD & Raman spectra, sheet resistance vs. temperature (20–120 °C), and UV–Vis–NIR spectra at 25 and 90 °C. The XRD and Raman spectra confirmed all prepared layers have a VO2 polycrystalline structure in monoclinic phase. We found among the studied samples CN30-70 and CN50-50 having desirable optical characteristics of peak visible transmittance of about 55%, with low transition temperatures (Tcr) of ∼42 and 31 °C, and also relatively high amounts of ΔT1700nm, ΔTsol and Tlum,av are good candidates for thermochromic smart windows, both from optical properties and economical fabrication method points of view.

Fabrication, structural, thermo-mechanical and opto-electrical behavior of anthranilamide compound

Anthranilamide (AAM) compound were fabricated via an alcoholic solvent assisted slow evaporation at room temperature for investigating the multi functional device applications. The solubility test was performed with different concentrations of AAM salt dispersed in 100 mL ethanol solvent to understand the crystallization process of fabricated material. The cell parameters, and diffraction peaks of the title compound were collected through nondestructive tool like single crystal XRD and powder XRD studies, and thus results showed the monoclinic structure. The fabricated material’s functional group, thermal stability, and hardness behavior were tested by various tool viz FT-IR, TG-DTA, and Vickers hardness analysis. With the aid of UV–vis–NIR spectrum, and frequency conversion test technique, optical transmittance and double harmonic generation efficiency values are detected to be 92% and 4.1 mV. Using electrical studies, the dielectric parameters and specific conductance of the title compound values are varied by applying a low frequency to a high frequency region at different temperatures (313, 323, and 333 K).

Third-order nonlinearity and functional data analysis of ADP-doped PVA/PVP polymer composites

The structural dependence of nonlinear optical properties associated with ADP-doped PVA/PVP polymer composites is discussed in this work. Polymer composites are fabricated using the solution casting method. X-ray diffraction (XRD) was used to perform structural analysis on these samples whose average crystallite size increases with an increase in dopant concentration. Results from UV–Vis–NIR spectra show that the samples are transparent in the IR region. The Z-scan technique was established by following the method described by Sheik-Bahae et al. The shape of the open aperture plot suggests that the samples exhibit two-photon absorption. The NLO properties such as nonlinear absorption coefficient ([Formula: see text], two-photon absorption cross-section ([Formula: see text] and the imaginary part of third-order nonlinear susceptibility [Formula: see text] were investigated at 1064 nm and these values were found to be in the order of [Formula: see text][Formula: see text]W/cm, [Formula: see text][Formula: see text]cm4/GW and [Formula: see text][Formula: see text]esu, respectively. The open aperture Z-scan method yielded optical limiting data, from which the optical limiting threshold was calculated to be in the order of [Formula: see text][Formula: see text]W/m2. Functional data analysis uses a suitable basis representation to assess the functional correlation between global and local variables.

Defect-induced Sr1−xPrxTiO3 crystallites by burial sintering and its optoelectronic applications

The band structure of SrTiO3 was altered by introducing Pr3+ in the Sr2+ site and subsequent graphite burial sintering. The asymmetric nature of the (310) peak in XRD and the emergence of Eg and B1g modes in the Raman spectrum suggest the transformation from cubic to tetragonal phase for the Sr1-xPrxTiO3 system with x ≥ 0.1. The development of the forbidden first-order Raman peaks and novel spectral properties are attributed to the local vibrational modes linked to oxygen vacancies. Structural variations in terms of lattice strain were investigated using a W–H plot, and morphological changes were analyzed by high-resolution FE-SEM. High infrared absorption in UV–Vis–NIR spectra and a significant reduction in band gap from 2.8 eV to 1.8 eV were accomplished through increased disorder in the lattice and the reduction of Ti4+. The blue shift in absorption spectra with Pr concentration can be used to tune the absorption range for sensing purposes. The formation of new electronic states observed here offers a novel approach for band gap modification in perovskites for photocatalytic and photovoltaic applications.