UV Vis NIR Spectrometer Research Articles

Metamaterial based sucrose detection sensor using transmission spectroscopy

In the present study, metamaterial based optical sensor is proposed and optimization of the proposed optical sensor for sucrose detection is done. In this paper single negative metamaterial surface is fabricated using E-beam lithography technique to be used as an optical sensor for broad wavelength range using UV–Vis–NIR spectrometer. The resultant sensitivity and detection accuracy of the proposed metamaterial based sensor is higher than simple thin film sensor, i.e. 1740.8 (nm/RIU) and 0.893 respectively. The center wavelength of the proposed optical sensor is 967 and 933 nm for gold and metamaterial based-sensor respectively, which ensures the larger bandwidth available in the case of metamaterial based-sensor. It is observed that high surface to volume ratio of metamaterial surface ensures the better sensitivity of the proposed sensor. Simple structure of presented metamaterial surface also makes sure reliable and precise fabrication of metamaterial surface.

Crystal structure, DFT and third order non-linear optical studies of an organic bisguanidinium isophthalate monohydrate single crystal

A conventionally grown organic nonlinear optical crystal bisguanidinium isophthalate monohydrate was structurally investigated using single crystal X-ray diffraction study. The lattice constants, supramolecular arrangements and the hydrogen bond formation of the title compound confirm the formation of novel organic crystalline material. The various functional groups present in the crystalline material were resoluted by employing FT-IR spectral analysis. The wide-range optical transparency of the compound in the entire visible region ensures the optical quality with a lower cut-off wavelength at 298 nm was analysed experimentally using UV–vis–NIR spectrometer. The support of DFT was scrutinized to report the optimized structure, electronic state properties, hyper-conjugative interactions and frontier molecular energy gap of the bisguanidinium isophthalate compound. The charge transfer mechanism of bisguanidinium isophthalate compound from isophthalic acid to guanidine compound was also interpreted using theoretical DFT. The computational evaluation of charge stabilities as a result of charge delocalization was construed with the ratification of natural bonding orbital (NBO). The assessed thermal stability of bisguanidinium isophthalate crystal is 120 °C which was analysed by thermogravimetric and differential thermal analyses. To determine the third-order nonlinear optical property with quantitative results of nonlinear refractive index, nonlinear absorption coefficient and optical susceptibility was ascertained using Z-scan technique.

BioMOF@cellulose fabric composites for bioactive molecule delivery

This work describes in situ synthesis and application of the zinc glutamate Bio Metal-Organic Framework (BioMOF) supported on cellulose fabrics as a dual material for nitric oxide (NO) and 5-fluorouracil (5FU) controlled delivery for wound and/or skin cancer therapy. In situ synthesis of BioMOF on the cotton fabric was successfully achieved and the incorporation of NO and 5FU was studied. We have observed that BioMOF doped with FeII metal ions has a beneficial impact on NO incorporation. The products obtained were analyzed with X-ray powder diffraction (XRPD), Fourier-Transform Infrared Spectroscopy-Attenuated Total Reflectance (FTIR-ATR), Field Emission Scanning Electron Microscopy (FESEM), Diffuse Reflectance UV–Vis-NIR spectrometer, X-Ray pHotoelectron Spectroscopy (XPS), Thermogravimetric Analysis (TGA), N2 adsorption analysis, Transition UV–Visible spectroscopy, and Gas Chromatography-Mass Spectroscopy (GC–MS). Moreover, antibacterial and anticancer activity in melanoma skin cell was carried out in order to prove the biological activity of the drug-loaded BioMOF on treated cellulose fabrics. These studies are indicative of the potential of BioMOF@cellulose fabric composites for the controlled delivery of bioactive molecules on the wound and/or cancer.

Fabrication of Robust Multifaceted Textiles by Application of Functionalized TiO2 Nanoparticles

Utilization of nanoparticles has increased significantly over last decade due to their extraordinary properties they offer. They are being used extensively in all fields including textiles but the biggest constraints of nanoparticles in textiles is their non-durability. One way to address this issue is the surface functionalization of nanoparticles for increasing their adhesion with textiles. Titanium dioxide (TiO2) has been used for making self-cleaning fabrics. In this study, TiO2 nanoparticles were functionalized with 3-(Trimethoxysilyl) propyl-N,N,N-dimethyloctadecyl ammonium chloride and 3-Glycidoxypropyl)trimethoxy-silane to improve their adhesiveness when applied to textile substrates. Functionalized TiO2 nanoparticles and the treated cotton textiles were characterized using thermogravimetric analysis (TGA), zeta potential analyzer, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-Ray diffraction (XRD) and ultraviolet transmittance spectrophotometry. Water contact angle (WCA) was measured for superhydrophibicity assessment. Treated fabric showed WCA of 150.5° making it superhydrophibic. Photocatalytic dye degradation was observed by using UV–Vis NIR spectrometer. Antibacterial activity was examined against Gram-positive and Gram-negative bacteria, qualitatively and quantitatively. The prepared cotton fabric showed durable functionality up to 20 industrial laundering cycles making it potentially suitable for both outdoor and indoor applications.

Co-sputtered Cu2ZnTi(S:Se)4 absorbers for thin film solar cells

Thin film solar cells are an exciting topic for low cost and high efficient solar cells. Owing to the high price of the indium metal in the fabrication of copper indium gallium diselenide (CIGS) solar cells, Cu2ZnSn(SSe)4 thin films are used as a new material to reduce the cost and increase the efficiency.As an alternative absorber material for solar cell production, Cu2ZnTi(S:Se)4 thin films were deposited by the co-sputtering method at various temperatures. During the deposition, Cu, ZnSe and Ti targets were used as metal sources. The Cu2ZnTi(S:Se)4 thin films were annealed in H2S:Ar (1:9) atmosphere. The morphological, structural and optical properties of Cu2ZnTi(S:Se)4 thin films was analyzed using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) Raman spectroscopy and UV–Vis–NIR spectrometer. It was seen that the thin films had good optical absorption till the infrared region and the band gap of the Cu2ZnTi(S:Se)4 thin films were smaller than the conventional Cu2ZnSnS4 thin films. Furthermore, fabrication of a solar cell with 1.96% power conversion efficiency was reported using a Cu2ZnTi(S:Se)4 thin film as a low cost absorber layer.

Judd-Ofelt Parameters of Erbium Doped Zinc Phosphate Glass Containing Natural Ferrite Oxide Nanoparticles

Erbium ions (Er3+) doped zinc phosphate glass system with varying contents of natural ferrite (Fe3O4) nanoparticles were prepared using melt quenching method. The glass is characterized by x-ray diffraction (XRD) and UV-VIS NIR spectrometer. It is observed that the amorphous nature of the glass is confirmed by x-ray diffraction. The absorption spectra of the glass are recorded in the UV-Visible in the range of 400-1600 nm. The UV-VIS NIR spectra reveal ten absorption peaks centered at 376, 406, 420, 486, 522, 546, 652, 798, 976 and 1534 nm, correspond to the transitions from the ground state 4I15/2 to higher 4I13/2, 4I11/2, 4I9/2, 4F9/2, 4S3/2, 2H11/2, 4F7/2, 4F3/2, 2H9/2, 4G11/2 levels, respectively. Effects of natural ferrite oxide nanoparticles on the absorption and emission properties of the synthesized glasses were analyzed via Judd-Ofelt (J-O) theory. The J-O intensity-parameters (W2, W4, W6) analysis demonstrate a significant increase of spectroscopic quality factors.Keywords: Fe3O4 NPs, Absorption, Judd-Ofelt.

Improved broadband antireflection in MoO3/GaAs heterojunction

Large area surface micro-structuring is most commonly used to reduce the reflection loss and improve the light absorption in solar cells, photo-detectors and image sensors. Herein, chemically prepared textured GaAs with improved absorption in the entire range of the solar spectrum is investigated using UV–Vis–NIR spectrometer, showing that an average specular reflectance can be reduced to ~ 0.2% in the wavelength range of 3000–300 nm. The sputtered MoO3 thin film (10 nm) on textured GaAs further reduces the reflection loss down to ~ 0.1% (average value) in same wavelength range, i.e., 300–3000 nm. The phase, morphology, composition, and transport properties of the thin films were investigated using XRD, SEM, AFM, XPS, and Keithley source meter, respectively. SEM and AFM scanning show highly ordered elongated microstructure has been induced on pristine GaAs substrate after wet chemical etching. XRD analysis shows amorphous nature of the MoO3 thin film. In addition, XPS studies confirm that MoO3 thin film present on the surface of textured GaAs. Moreover, hole-blocking property of the MoO3 thin film has been studied with the help of Anderson model. Further, current–voltage characteristics (under dark condition) show rectifying behavior of the heterojunction (Ag/MoO3/GaAs/Ag). Hence, the present study is not only important for the basic understanding of charge transports across the heterojunction, but also to also to design hole-blocking-based solar cell.

Durable silica antireflective coating prepared by combined treatment of ammonia and KH570 vapor

Sol–gel silica antireflective (AR) coatings possess a high specific surface area that is more susceptible to be contaminated by absorption of contaminants from the environment, which will increase the refractive index and reduce the transmittance. Ammonia and γ-methacryloxypropyltrimethoxysilane (KH570) vapor treatment was employed to passivate the silica AR coating, thereby enhancing the environmental stability. The properties of the coatings were characterized with Fourier transfer infrared absorption spectroscopy, scanning electron microscopy, atomic force microscopy, UV–Vis–NIR spectrometer, and contact angle measurement. The results showed that after the vapor treatment, the coatings became denser and the environmental stability was greatly improved. After being exposed to a humid environment (RH > 90%) and low-vacuum environment with intentionally induced organic contaminants for 60 days, the transmittance of the modified SiO2 coating decreased by only 0.08% and 0.2%, respectively. Meanwhile, the average transmittance decreased by only 0.02% after being rubbed for 1000 cycles, indicating that the co-treated coating also possessed a good abrasion resistance.

Thermally induced optical nonlinearity and optical power limiting action of 2,4,5-trimethoxy-4′-nitrochalcone under CW laser regime

In the present work, we report the results of thermally induced third-order nonlinear optical (NLO) properties of 2,4,5-trimethoxy-4[Formula: see text]-nitrochalcone (abbreviated as 2,4,5TMNC) investigated by [Formula: see text]-scan technique using continuous wave (CW) Argon ion laser at a wavelength of 488[Formula: see text]nm with adjusted power ranging from 2.5[Formula: see text]mW to 20[Formula: see text]mW. The experiments were performed by varying the concentration of the molecules in solution. The sample demonstrated strong reverse saturable absorption (RSA) and self-defocusing effect (negative nonlinear refractive index). The estimated values of the NLO absorption coefficient ([Formula: see text], nonlinear refraction ([Formula: see text] and absolute nonlinear susceptibility [Formula: see text] are found to be of the order of 10[Formula: see text][Formula: see text]m/W, 10[Formula: see text][Formula: see text]m2/W and 10[Formula: see text][Formula: see text]esu, respectively. The magnitude of the nonlinear absorption coefficient ([Formula: see text] was found to increase with concentration. The linear absorption spectrum of 2,4,5TMNC was measured using UV–Vis–NIR spectrometer. The optical band gap (Eg) value of title chalcone is obtained from the tauc’s plot of ([Formula: see text] versus [Formula: see text]. The optical limiting performance of 2,4,5TMNC is also investigated for device application. In addition to the above, the computation studies are also carried out to attain the ground state molecular geometry which is found in close to experimental results. Time-Dependent- Density Function Theory (TD-DFT) was used to determine the UV–Vis spectrum at B3LYP/6-31G* level of theory and found to be comparable with experimental data. The HOMO–LUMO energy gap was also determined and discussed. The results promote this chalcone derivative as a promising candidate for optical limiting and optical switching applications.

Crack-Free TiO2 Thin Film via Sol-Gel Dip Coating Method: Investigation on Molarity Effect

Titanium dioxide, (TiO2) is transparent to visible light and excellent in optical transmittance. In this experiment, TiO2 thin films have been fabricated on glass substrates by sol-gel dip coating method. Sol-gel dip coating technique can provide corrosion protection performance and can produce thick coating. Due to the thick coating, the possibility to get a crack thin film is high. Therefore, this paper is to investigate a crack-free TiO2 thin film for optical sensor application where it is needed the most. The films were subjected to different molar concentration solution with 0.01M, 0.05M, 0.10M, 0.15M and 0.20M. The thin films are then characterized by field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), surface profiler and UV-VIS NIR spectrometer. From this study, a crack-free of TiO2 thin film was obtained and this thin film could be used for optical sensor application later.

Fabrication of Co + F Doped ZnO Films for Improved Visible Light Responsive Photocatalysis

The aim of this work is to investigate the efficacy of nebulizer sprayed ZnO–Co–F thin films for degrading the methylene blue (MB) aqueous solution under visible light irradiation. The physical properties of the prepared samples like structural, surface morphological and optical properties are studied using X-ray diffractometer (XRD), Scanning Electron Microscope (FESEM), UV-vis NIR spectrometer, spctroflurometer (PL) and Fourier Transform Infrared spectrometer (FTIR). The photocatalytic studies revealed that ZnO–Co–F film exhibited superior degradation efficiency over ZnO–Co and ZnO against MB as evinced by the degradation rate constants, 0.0782, 0.0475 and 0.0289 min–1, respectively. This study showed that Co + F doping helps to remove the major limitations of ZnO and thereby leads towards better visible light activity. The structural and optical studies revealed the proper incorporation of Co2+ and F– ions into the ZnO lattice and the reduction in band gap. PL emission confirmed that Co + F doping reduces the electronhole recombination rate and increases the availability of free carriers.

Growth, structural, thermal, dielectric and nonlinear optical properties of potassium hexachloro cadmate (IV) a novel single crystal

The Potassium hexachloro cadmate (IV) (PHC) single crystal was grown from the aqueous of the solution by a controlled evaporation method. Single crystal XRD solved the structure. FTIR is used to identify the functional groups of grown crystal. The UV–Vis–NIR spectrometer was used to find out the UV cut off region and to calculate the optical band gap of the Potassium hexachloro cadmate (IV) single crystal. The EDAX spectrum has been used to identify the compounds present in title compound. The TG-DTA profile shows the thermal stability of the grown crystal of Potassium hexachloro cadmate (IV). The Vicker's hardness measurement was used to calculate the material hardness of the title compound. The dielectric loss and constant varied with frequencies and activation energy is also calculated. The solid state parameters like plasma energy, Penn gap, Fermi energy, electronic polarizability using Penn analysis and Clausius-Mossotti equation were also calculated for the title compound. The Z-scan technique is used to calculate the third order nonlinear susceptibility of a real and imaginary part.

Spectral modeling of meteorites at UV-vis-NIR wavelengths

We present a novel simulation framework for assessing the spectral properties of meteorite specimens. The framework utilizes a ray-optics code, which simulates light scattering by Gaussian-random-sphere particles large compared to the wavelength of the incident light and accounts for internal diffuse scatterers. The code uses incoherent input and computes phase matrices by utilizing incoherent scattering matrices. Reflectance spectra are modeled by introducing a combination of olivine, pyroxene, and iron, the most common materials present in meteorites that dominate their spectral features. The complex refractive indices of olivine and iron are obtained from existing databases. The refractive indices of pyroxene are derived using an optimization that utilizes our ray-optics code and the measured spectrum of the material. We demonstrate our approach by applying it on the measured meteorite reflectance spectra obtained with the University of Helsinki integrating-sphere UV–vis-NIR spectrometer.

Comparison the optical properties for Bi2O3 and NiO ultrathin films deposited on different substrates by DC sputtering technique for transparent electronics

Bismuth and Nickel transparent oxides thin films were grown on glass and flexible polyethylene terephalate (PET) substrates by DC sputtering technique at room temperature 300 K. The structures of Bi2O3 and NiO films were analyzed by X-ray diffraction (XRD) analyses and scanning electron microscopy (SEM). A profilometry is used to measure the thicknesses of the ultrathin films. These values were established by a spectro-ellipsometry technique with a new amorphous dispersion model in the range of 200 nm–2200 nm with one nm increment. In addition, the optical constants of these films were investigated using a double beam UV–Vis–NIR spectrometer and a spectro-ellipsometry and compared using the same wavelength range. They present an excellent agreement. According to the optical transmittance spectra of the films a high average transmittance in the visible region of each sample deposited onto different substrates is measured. Moreover, the absorption coefficients and the optical energy gaps for four types of optical transitions (allowed direct, forbidden direct, allowed indirect, forbidden indirect) of the films were determined and compared with the two different techniques. Finally, the nature of the structure and morphology of Bi2O3 and NiO ultrathin films has been analyzed and compared.

Judd–Ofelt analysis of spectroscopic properties of Sm3+ doped P2O5–SrO glasses

The glass composition P2O5 60%, SrO 40% (mol%) was prepared then doped with Sm3+ with different mol% (3.2, 6.4, 9.6 and 15%). UV–VIS–NIR spectrometer was used to carry out the absorption spectra of the studied glass samples. The most nominal transitions were assigned among a large number of transitions. Then the radiative properties of the Sm3+ ions were calculated using J–O analysis. The results show a large value of Ω2 than the values Ω4 and Ω6. Another parameter such as the oscillator strength, radiative life time, the transition probabilities, the spectroscopic quality and factors branching ratio of several excited states of the Sm3+ ions was calculated. The laser transition level from 6F9/2→6H5/2, the gain cross-section has been predicted. The emission profile of Sm3+ ions in the present glass shows that the peak of the gain coefficient is shifted toward shorter wavelength as the increase of the inversion. The Optical properties introduce this doped Sm3+ glass as a promising candidate for optical applications.

Deposition rate dependant formation and properties of Sn2S3 and SnS thin films by co-evaporation

We report the effect of deposition rate on the formation and properties of tin sulfide (Sn2S3 and SnS) thin films prepared by co-evaporation technique. The structural, morphological and optical properties of these films have been investigated as the function of deposition rate. X-ray photoelectron spectroscopy analysis confirmed the transformation of Sn2S3 phase to SnS phase with the increase in deposition rate of tin. The structural analysis by XRD and Raman showed the formation of Sn2S3 and SnS phases. The variation in surface morphology and roughness of the as- deposited films have been examined by scanning electron microscopy (SEM) and atomic force microscopy (AFM). UV–Vis–NIR spectrometer was employed to record the transmission spectra of the samples in the wavelength range of 200–3000 nm. Film thickness (d), optical band gap (Eg), refractive index (n) and extinction coefficient (k) of the deposited thin films are estimated from the optical data. Photo conductivity of the as-deposited films has been studied using two probe method. Hall effect measurements show an n-type to p-type conversion in electrical conductivity with increase in deposition rate.

Synthesis and characterization of Cu2Sn1−xGexS3

Cu2SnS3 (CTS) is a promising compound for use as an absorber layer in thin‐film solar cells because it is made up of low‐cost and abundant elements. However, the band gap energy of 0.94 eV for monoclinic Cu2SnS3 is less than the optimal value for absorber layers in single‐junction solar cells. On the other hand, the band gap energy of Cu2GeS3 (CGS) is approximately 1.5–1.6 eV. Therefore, in this study, we carried out the synthesis of Cu2Sn1−xGexS3, which is a solid solution of Cu2SnS3 and Cu2GeS3. The structure of the prepared samples was investigated using X‐ray diffraction and Raman analyses. Diffuse reflectance spectra were obtained using a UV–Vis–NIR spectrometer and used to estimate the band gap energy. In X‐ray diffraction patterns from the synthesized compounds, the diffraction peaks were found to shift to higher 2θ values with increasing x, indicating a decrease in the lattice constants. In addition, the estimated band gap energy increased from 0.86 to 1.53 eV with increasing x. Cu2Sn1 − xGexS3 is, therefore, a potential candidate for use as the absorber layer in thin film solar cells because its band gap energy can be adjusted simply by varying its composition.

Effect of rapid thermal annealing on optical properties of zinc sulphide thin films

Zinc sulphide (ZnS) thin films were prepared on clean surface glass substrates by thermal evaporation under pressure of 10−5 Torr. Thickness of thin films was uniform 55 nm measured by ellipsometry. These films were also kept into a quartz glass tube for rapid thermal annealing at 30 and 60 s by using a 500 W halogen lamp for crystalline the structure. The cubic structure of the films was verified by X-ray diffraction and the intensity of predominant peak increases with annealing time. The optical absorption study was carried out by UV–ViS–NIR spectrometer in the range of 200–800 nm. The optical band gap changes from 3.48 to 3.08 eV, with rapid thermal annealing. Thermo electric power studies confirm the n-type nature of ZnS thin films and thermoelectric power increases with increase in temperature. This study is important because ZnS is potentially important material for antireflection coating and window layer material in hetero-junction solar cells.

Enhancing the electron transfer and band potential tuning with long-term stability of ZnO based dye-sensitized solar cells by gallium and tellurium as dual-doping

A series of ZnO nanoparticles with Ga and Te dual-doping were successfully synthesized by using a facile sol–gel route, and their performance as the photoanode material in DSSCs was employed for the first time. The effects of simultaneously Ga–Te dopants into ZnO host (GaxTe1-xZnO where the values of x ranging from 0 to 1mol % with increments of 0.25mol %) on the structural, optical, morphological, and compositional properties of the resulting samples were characterized via XRD, Raman, UV–vis–NIR spectrometer, PL, BET, AFM, FE–SEM, EDX, and XPS measurements. The incorporation of Ga–Te enlarges the surface area of the photoanodes, leading to higher dye-loading capability. Moreover, the PL intensity of pure ZnO drastically decreases by Ga–Te dopants, which demonstrates the reduction of oxygen vacancies, indicating the slow recombination of photoinduced charge carriers. Owing to the doping effect of Ga–Te, the energy conversion efficiencies of the DSSCs based on these photoanodes lie in the range of 4.79–7.08%, which is higher than that of pure ZnO (3.53%). This improvement of efficiency can be mainly ascribed to the combined effects of faster electron transport rate, retarded charge recombination, enhanced dye adsorption capability, longer electron lifetime as well as shifted negatively of conduction band edge in dual-doped ZnO films. Furthermore, it is noteworthy that after 1200h, the degraded Ga0.25Te0.75ZnO device still shows 86% of their initial efficiency. This study provides a strategy for constructing self-powered systems using a device such as GaxTe1-xZnO based DSSC described here for the first time.

Physical, thermal, structural and optical properties of Dy3+ doped lithium alumino-borate glasses for bright W-LED

Rare earth (RE) doped glasses have potential applications due to their emission efficiencies of 4f–4f and 4f–5d electronic transitions. Among all the rare earths, Dy3+ doped glasses have drawn much interest among the researchers for their intense emission in the visible region from 470 to 500nm and around 570 to 600nm. The physical, thermal, structural and optical properties of Dy3+ doped lithium alumino-borate glasses (LABD glasses) have been studied for white LED (W-LED) application. The glasses were synthesized by conventional melt quench technique. X-ray diffraction spectra revealed the amorphous nature of the glass sample. An FTIR spectrum was carried out to study the glass structure and various functional groups present in the LABD glasses. Optical absorption spectra were recorded by UV–vis-NIR spectrometer. Allowed direct and indirect band gaps were obtained by Tauc's plot. Thermal parameters like glass thermal stability (∆T), Hruby's parameter (Kgl), etc. were calculated by DTA graph. Photoluminescence excitation and emission spectra's were measured at room temperature. The emission spectra shows two intense emission bands at around 482nm (blue) and 574nm (yellow) corresponds to the 4F9/2→6H15/2 and 4F9/2→6H13/2 transitions respectively along with one feeble band at 662nm (red) corresponds to 4F9/2→6H11/2 transition. The CIE chromaticity co-ordinates were calculated for all glass samples. CIE chromaticity diagram shows glass LABD-4 containing 0.5mol% Dy2O3 with colour co-ordinates X = 0.34 and Y = 0.38 have highest emission intensity. These glasses having emission in the white region and thus can be used for bright white LED.