UV Vis Transmission Spectra Research Articles

Study on the preparation and characterization of cross-linked film of human hair keratin and cellulose

ABSTRACTFilms of human human hair keratin were prepared from the mixture of keratin and cellulose and were cross-linked by glutaraldehyde. Properties and structure of the film were characterized by Fourier Transform Infrared Spectroscopy(FTIR), UV-visible transmittance spectra, X-Ray Diffraction(XRD), Thermogravimetric Analysis(TGA, DTG) and strength tester. The result showed that glutaraldehyde reacted with hair keratin and cellulose, a high tensile strength of 109.31MPa, elongation at break of 7.8%, moisture absorption rate of 11.36%, moisture retention rate of 63.75%, a lower UV transmittance, thermal degradation temperature of about 310°C and a higher crystallinity. The results indicate that the cross-linked film may be a promising material for textile material.

Photocatalytic study on SrBi2B2O7 (SrO-Bi2O3-B2O3) transparent glass ceramics

SrO-Bi2O3-B2O3 transparent glass ceramic was fabricated via conventional melt-quenching technique. Structural analysis like X-ray diffraction, Raman and Fourier transform infrared spectroscopies were performed to confirm SBBO glass ceramic formation. As-quenched glass samples exhibited X-ray diffraction peaks corresponding to SrBi2B2O7 which were further confirmed through Field Emission Scanning Electron Microscope. UV–vis transmission spectra revealed 60%–80% transparency in 500–800 nm spectral range. Absorption study revealed direct bandgap of 2.58 eV. Resazurin (Rz) ink was used as an indicator to monitor photocatalytic activity for self-cleaning purposes. Digital photographic method was performed to examine photoreduction of Rz ink. Further, the pseudo-first order kinetics was istimated for Methylene blue (MB) degradation. Nucleation of nanoparticles of SrBi2B2O7 over glass surface were found responsible for photocatalytic activity. Contact angle with water droplet for SBBO glass ceramic was 63.43°. Reduced Young’s modulus (Er) and Vickers hardness (Hv) were found 59.9 GPa and 5.01 GPa, respectively.

Design of UV-absorbing PVDF membrane via surface-initiated AGET ATRP

Herein, PVDF membranes with excellent UV-absorbing property were first synthesized through grafting the polymerizable low-molecular-weight organic UV-absorber 2-hydroxy-4-(3-methacryloxy-2-hydroxylpropoxy) benzophenone (BPMA) onto α-bromoester-functionalized PVDF membranes via the surface-initiated activator generated by electron transfer atom transfer radical polymerization (SI-AGET ATRP). The surface initiators were immobilized by the reaction between 2-bromoisobutyryl bromide (BIBB) and the hydroxylated PVDF membranes. PVDF-g-PBPMA membranes with different grafting densities were obtained by tuning the polymerization time and the modified membranes were characterized by 1H-NMR, FT-IR, XPS, SEM, UV–vis Spectrophotometer, TGA and DSC. The experimental results indicated that PBPMA chains were successfully introduced onto PVDF membranes. Most importantly, the PVDF-g-PBPMA membranes exhibited outstanding UV-shielding property. UV–vis transmittance spectra showed that most UV light below 360 nm could be absorbed by PVDF-g-PBPMA membranes and the whole UV light region (200–400 nm) can be blocked with the reaction time increased.

Realization of strong violet and blue emissions from ZnO thin films by incorporation of Cu ions

In recent years, Cu-doped ZnO materials have attracted wide attention due to some unique properties, such as p-type conduction, room-temperature ferromagnetism and plentiful luminescence behavior. In this work, Cu-doped ZnO thin films with different doping levels were prepared by sol–gel method. The structural, morphological features and the composition of the samples were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectroscopy (EDX), respectively. The optical properties were analyzed by the UV–visible transmittance spectra and fluorescence spectra. The Cu-doping in a low concentration does not influence the crystal phase of wurtzite ZnO and has a very small impact on c-axis preferred orientation of ZnO thin films. With the increase of Cu-doping concentration, the Cu ions are gradually changed from dominant Cu+ ions to dominant Cu2+ ions. Cu-doping in a low concentration caused strong blue-violet emissions in ZnO thin films. The violet emission is attributed to the transition of electrons from the conduction band to Cu+ acceptor levels, and the blue emission is ascribed to the transition of electrons from Cu2+ donor levels to Cu+ acceptor levels.

The Effect of Lithium Molybdate in Tungsten Trioxide Electrochromic Film

Lithium molybdate doped tungsten trioxide electrochromic films were prepared from tungsten trioxide precursor and lithium molybdate powder by sol-gel and dip coating methods on fluorine doped tin oxide glass. The films, which synthesized were flat and amorphous structure, which confirmed by x-ray diffraction patterns. From UV-vis transmittance spectra within the wavelength from 400 to 800 nm. and cyclic voltammogram at the applying a potential of 1.0 V (bleached state) to -1.0 V (colored state) in sulfuric acid 0.5 M solution. The doping lithium molybdate 10 mol% films showed good result in terms of transmittance modulation, high diffusion coefficient and optimal surface area. Therefore, doping lithium molybdate 10 mol% has better outcome when compared to undoped lithium molybdate.

Synthesis of gluconate modified layered titanate particles using hydrolysis reaction of Ti alkoxide and characterization of their swelling behavior and structural color

Gluconate modified layered titanate particles and their sol were prepared using titanium tetraisopropoxide (TIP) and gluconic acid aqueous solution. A mixture of ethylene glycol solution of TIP and gluconic acid aqueous solution was heated at 368 K for 24 h to obtain sol. The particles, which had a layered structure, were dispersed stably in the sol. Furthermore, dialysis of the sol with H2O formed sol with stable dispersion of the layered titanate particles in H2O. Fourier -Transform Infrared Spectroscopy (FT-IR) and Raman spectra of the obtained particles indicated that they were layered titanate particles with gluconic acid on the surface, that is, the particles were gluconate modified layered titanate. Drying the sol spontaneously formed plate morphology. The aggregated structure of the layered titanate particles swelled with H2O and formed gel. The addition of H2O to the aggregated structure finally lead to a stable dispersion of the layered titanate particles in H2O, when the weight ratio of H2O to the layered titanate was higher than 15. According to SEM observation of the freeze dried gels, the layered titanate particles had also plate morphology with a high aspect ratio and lamellar structure. Furthermore, when glycerol was dissolved into the sol of the layered titanate particles and the sol was heated to evaporate H2O, alternately integrated layered structures were obtained and they showed structural color, which depended on the weight ratio of the layered titanate particles and glycerol. UV–VIS transmittance spectra and photographs of the complex gel plate between the gluconate modified layered titanate particles and glycerol. The structural color depends on the weight ratio of (layered titanate sol/glycerol).

The trade-off between electrochromic stability and contrast of a thiophene—Quinoxaline copolymer

The stability of organic electrochromic devices is a crucial issue for their applications. However, until now the degradation mechanism of electrochromic materials are still not fully understood especially for electrochromic conjugated polymers (ECPs). To improve device stability, intensive investigation on the degradation mechanism of ECPs is urgently needed. Here we report our study on the electrochromic degradation in a thiophene–quinoxaline copolymer: poly [2,3-bis-(3-octyloxyphenyl)quinoxaline-5,8-diyl-alt-thiophene-2,5-diyl] (TQ1). The results of X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectra (UPS) and UV–vis transmission spectra reveal that there are three main factors during the electrochromic degradation of TQ1. The first one is anion (ClO4−) irreversibly deep trapped, while the second is peroxidation of the thiophene group in TQ1. Both factors reduce the conductivity and electrochromism of TQ1. The third is structural relaxation resulting lager conjugated system of TQ1 molecules in film, which is gradually developed during 400 cycling of CV at a narrow potential range (0–1V). When a potential range 0–0.7V is applied, all three factors are prohibited, no electrochromism degradation is observed anymore, although the contrast becomes smaller. Our investigation systematically discloses the degradation mechanism during the electrochemistry processing of a ECP (TQ1), demonstrating the significance of trade-off between the electrochromic stability and contrast of the ECP.

Optical and Structural Characteristics of Nanocrystalline ZnO:Cd Ceramics

Nanostructured cadmium (Cd) doped ZnO ceramic thin films were deposited on glass substrates by the sol-gel spin coating method and characterized by X-ray diffraction (XRD), scanning electron microscopy and UV-VIS-NIR spectrophotometry. The XRD analysis showed that thin films were crystalline with hexagonal wurtzite structure. The preferred orientation of un-doped and Cd-doped ZnO thin films lies along the (002) plane. FESEM images revealed that the morphology consists of spherical, non-spherical and partly cylindrical structures. The results of EDX showed that Cd was doped into the ZnO structure. The UV-Vis transmittance spectra showed that substitution of Cd into ZnO leads to bandgap narrowing. The Urbach energy increases with the increase in Cd concentration. The prepared nanostructured cadmium (Cd) doped ZnO ceramic thin films can be used in electronic device technologies.

Inverted organic solar cells with solvothermal synthesized vanadium-doped TiO2 thin films as efficient electron transport layer

We investigated the effects of using different thicknesses of pure and vanadium-doped thin films of TiO2 as the electron transport layer in the inverted configuration of organic photovoltaic cells based on poly (3-hexylthiophene) P3HT: [6-6] phenyl-(6) butyric acid methyl ester (PCBM). 1% vanadium-doped TiO2 nanoparticles were synthesized via the solvothermal method. Crystalline structure, morphology, and optical properties of pure and vanadium-doped TiO2 thin films were studied by different techniques such as x-ray diffraction, scanning electron microscopy, transmittance electron microscopy, and UV–visible transmission spectrum. The doctor blade method which is compatible with roll-2-roll printing was used for deposition of pure and vanadium-doped TiO2 thin films with thicknesses of 30 nm and 60 nm. The final results revealed that the best thickness of TiO2 thin films for our fabricated cells was 30 nm. The cell with vanadium-doped TiO2 thin film showed slightly higher power conversion efficiency and great Jsc of 10.7 mA/cm2 compared with its pure counterpart. In the cells using 60 nm pure and vanadium-doped TiO2 layers, the cell using the doped layer showed much higher efficiency. It is remarkable that the external quantum efficiency of vanadium-doped TiO2 thin film was better in all wavelengths

Formation of Subsurface W5+ Species in Gasochromic Pt/WO3 Thin Films Exposed to Hydrogen

M/WO3 (M = Pt, Pd) systems formed by a porous WO3 thin film decorated by metal nanoparticles are known for their reversible coloring upon exposure to H2 at room temperature. In this work, this gasochromic behavior is investigated in situ by means of near-ambient photoemission (NAPP). Pt/WO3 systems formed by very small Pt nanoparticles (10 ± 1 nm average size) incorporated in the pores of nanocolumnar WO3 thin films prepared by magnetron sputtering at an oblique angle have been exposed to a small pressure of hydrogen at ambient temperature. The recorded UV–vis transmission spectra showed the reversible appearance of a very intense absorption band responsible for the blue coloration of these gasochromic films. In an equivalent experiment carried out in the NAPP spectrometer, W 4f, O 1s, Pt 4f, and valence band photoemission spectra have been recorded at various photon energies to follow the evolution of the reduced tungsten species and hydroxyl groups formed upon film exposure to hydrogen. The obtained res...

Structural and optical properties of TiO2–Ge nanoparticles prepared through laser ablation in liquid medium

Quantum dot (QD) composite nanoparticles of titania germanium (TiO2–Ge) were fabricated by pulsed laser ablation of composite targets of TiO2–Ge immersed in deionized water. The single phase crystallanity, lattice parameters, and the evaluation of crystallite size of nanoparticles was investigated by X-ray diffraction (XRD). The morphology of the samples was analyzed through scanning electron microscopic studies. The average particle size calculated through XRD and measured through scanning electron microscope is in the range from 18 to 29 nm and are in agreement with each other. Compositional study was carried out through electron dispersive X-ray analysis showing that the ablation rate of Ge is smaller than TiO2. Optical properties were measured by UV–visible transmission spectra and Raman spectroscopy. The band gap of composite particles varies from the UV to the visible range by varying concentration of Ge QDs. This work shows that pulsed laser ablation in liquid media is an easy approach to synthesize ultrafine, contamination-free nanosized material, which is difficult to produce by other conventional methods.

Characterization of RF Sputtered-ZnS Thin Film Grown at Various Annealing Temperatures

ZnS thin films were deposited onto glass substrates by radio (RF) magnetron sputtering at room temperature. The films were grown at various annealing temperatures in vacuum at the range of 100–350 °C for 60 min. The effects of annealing temperatures on the structural and optical properties of the annealed samples were investigated with X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and UV-visible transmission spectra. XRD patterns of ZnS thin films annealed in vacuum show a single peak at 2 = 28.91° and a preferred orientation along the (111) reflection plane, indicating a zinc blende structure. The intensity of the diffraction peaks is increased with annealing temperatures. FESEM images reveal that the particle size is enhanced from 22.6 nm (at 100 °C) to 48.7 nm (at 350 °C) with increase in the annealing temperatures. The optical band gap of the films shifts to a higher energy and the calculated value shows an increment from 3.27 to 3.51 eV as the growth temperature increases. The structural and optical properties of ZnS thin films are significantly affected by their annealing temperatures.

Identification of Counterfeit Alcoholic Beverages Using Cluster Analysis in Principal-Component Space

A study of 153 brands of commercial vodka products showed that counterfeit samples could be identified by introducing a unified additive at the minimum concentration acceptable for instrumental detection and multivariate analysis of UV-Vis transmission spectra. Counterfeit products were detected with 100% probability by using hierarchical cluster analysis or the C-means method in two-dimensional principal-component space.

Ag nanoparticles decorated ion-beam-assisted TiO2 thin films for tuning the water splitting activity from UV to visible light harvesting

Abstract In this study, tuning of the photoelectrochemical (PEC) water splitting activity from UV to visible region was achieved on RF magnetron sputtered TiO 2 thin films grown under various Ar ion-beam energies (0, 60 and 110 eV). We propose a new strategy of energetic Ar ion-beam projection towards the substrate surface during the film growth. The resulting TiO 2 films were decorated with silver (Ag) nanoparticles for efficient plasmon-enhanced PEC water splitting activity under visible light illumination. Firstly, the ion-beam-energy induced a well-defined anatase TiO 2 (101) phase with improved crystallinity, which is key factor responsible for the enhanced PEC activity. Interestingly, XPS studies revealed the presence of Ti 3+ states along with the Ti 4+ ones, which sensitively influence the UV and visible light absorption. Furthermore, AFM images revealed rough surface topography of the films, which is highly desirable for large area exposure to the electrolyte. In addition, the UV–vis transmittance spectra showed a stronger red shift in the optical absorption edge and a reduced band gap, which are crucial factors for charge carrier generation. Studies on Ag nanoparticles decorated TiO 2 films show that, due to the transfer of surface plasmon energy from the Ag nanoparticles to TiO 2 , efficient visible light water splitting activity was achieved. This is about five times higher than that observed for TiO 2 films under UV light. Comprehensively, this novel approach could pave the way for efficient visible-light-driven PEC water splitting activity.

Influence of Tb3+ concentration on the optical properties and Verdet constant of magneto-optic ABS-PZZ glass

Highly transparent magneto-optical (MO) glasses (heavily xTb-doped SiO2-B2O3-P2O5-ZnO-ZrO, x = 15, 25, 32, 35, 40 mol%) were prepared by high temperature melting-quenching technique. The optical and magnetooptical properties have been measured at room temperature. The infrared transmission spectra and XRD confirms that [BO4], [BO3], [SiO4], [PO4], [BPO4] units the glass structure without crystallization by accommodating more Tb ions. The typical absorption bands could be observed in the UV–vis transmission spectra ascribing to 5d–4f electronic transition of Tb3+ and the absorption edges shift to a longer wavelength by increasing the Terbium ions content. The intensity of the emission peaks and decay time which is in the order of milliseconds decreases caused by concentration quenching. The cross-relaxation is responsible for the luminescence gradually disappearing of 5D3. The highest Verdet constant of the prepared glasses at room temperature @632.8 nm is −136.648 rad/T/m and the contribution V/N of each ion Tb is proportional to mole volume.

Anomalous evolution of broadband optical absorption reveals dynamic solid state reorganization during eumelanin\xa0build-up in thin films

The origin of eumelanin optical properties remains a formidable conundrum preventing a detailed understanding of the complex photo-protective role of these widespread natural pigments and the rational design of innovative bioinspired materials for optoelectronic applications. Here we report the unusual kinetic and thickness-dependent evolution of the optical properties of black eumelanin polymers generated by spontaneous aerial polymerization of 5,6-dihydroxyindole (DHI) thin films (0.1–1 μm), consistent with peculiar solid state reorganization mechanisms governing broadband absorption. The complete reversal of eumelanin UV-visible transmittance spectrum curvature on passing from 0.2 to 0.5 μm thick films, the marked increase in visible extinction coefficients with increasing film thickness and the higher UV extinction coefficients in slowly vs. rapidly generated polymers concur to support distinct dynamic regimes of solid-state molecular reorganization at the nanoscale level and to do affect the development of broadband visible absorption. Solid state control of molecular reorganization disclosed herein may delineate new rational strategies for tuning optical properties in eumelanin thin films for optoelectronic applications.

Comparative study of Co and Ni substituted ZnO nanoparticles: synthesis, structural, optical and photocatalytic activity

Herein we report, cobalt (Co) and nickel (Ni) doped zinc oxide (ZnO) nanoparticles by a novel microwave irradiation method for the first time. The role of dopants on modification of structural, morphological, optical and photocatalytic properties of ZnO nanoparticles has been investigated. Powder X-ray diffraction (XRD) results suggest that, both pure and doped ZnO samples showed hexagonal wurtzite type structure and average crystalline size was found to be 38, 31 and 22 nm for pure and Co, Ni doped ZnO respectively, this value in good agreement with the particle size calculated by TEM micrographs. UV–Vis transmission spectra indicate that decrease in the optical band gap (Eg) with doping of metal ions into the ZnO host lattice and increase the surface recombination rate. The photo catalytic activity of the nanoparticles studied in the degradation reaction of Crystal Violet (CV) and Methylene blue (MB) under UV light irradiation. Co–ZnO possesses excellent photocatalytic activity for the degradation of MB when compared to that of Ni–ZnO and ZnO. The possible photocatalytic mechanism was also discussed in detail. The samples were further characterized by photoluminescence spectra and Fourier Transform Infrared Spectra (FTIR) analysis.

Preparation and optical properties of TeO2–BaO–ZnO–ZnF2 fluoro-tellurite glass for mid-infrared fiber Raman laser applications

A serial of novel fluoro-tellurite glasses with compositions of 60TeO2–20BaO–(20-x)ZnO–xZnF2 (x = 0, 2, 4, 5 and 6 mol%) were prepared. The compositional dependences of glass structural evaluation, Raman gain coefficient, UV–Vis transmission spectrum, IR transmission spectrum, linear refractive index and third-order nonlinearity were analyzed. The results showed that the addition of 6 mol% ZnF2 can further improve the Raman gain coefficient to as well as 52 × 10−11 cm/W and effectively decrease around 73% and 57% absorption coefficients respectively caused by free OH groups (@3.3 μm) and hydrogen-bonded OH groups (@4.5 μm) in glass. Addition of ZnF2 does not change the UV–Vis absorption edge, optical band gap energy and infrared region cut-off edge almost, while the linear refraction index and ultrafast third-nonlinearity show unmonotonic changes. These novel fluoro-tellurite glasses may be suitable candidates for using in mid-infrared Raman fiber laser and/or amplifier.

Synthesis and systematic investigations of Al and Cu-doped ZnO nanoparticles and its structural, optical and photo-catalytic properties

Here we report, copper (Cu) and Aluminum (Al) doped zinc oxide (ZnO) nanoparticles by a novel one step microwave irradiation method for the first time. Powder X-ray diffraction (XRD) reveals that both pure and doped samples assigned to hexagonal wurtzite type structure. The calculated average crystalline size decreases from 24 to 11 nm for pure and doped (Al and Cu) ZnO respectively, which is in good agreement with the particles size observed from Transmission Electron Microscope (TEM) analyses. A considerable red shift in the absorption edge and the reduction in the energy gap from 3.35 to 2.95 eV reveal the substitution of Al3+ and Cu2+ ions into the ZnO lattice analyzed by UV–Vis transmission spectra. The photocatalytic degradation of Methyl Violet (MV), Phenol and Rhodamine B (RHB) was investigated by using pure, Al and Cu doped ZnO catalyst under UV light irradiation. The results showed that the photocatalytic property is significantly improved by Cu doping concentration. This could be attributed to extended visible light absorption, inhibition of the electronehole pair’s recombination and enhanced adsorptivity of dye molecule on the surface of Cu–ZnO nanopowders. The samples were further characterized by photoluminescence spectra and Fourier Infrared Spectra (FTIR) analysis.

Growth and Characterization of a Nonlinear Optical Single Crystal: Bis(4-nitrobenzoate) Tetraaquamanganese (II) Dihydrate (BNMD)

Semiorganic optically transparent Bis(4-nitrobenzoate) tetraaquamanganese (II) dihydrate [Mn (p-NO2C6H4COO)2 (H2O)4]·2H2O (BNMD) single crystals were grown by slow evaporation technique at room temperature. Single crystal X-ray diffraction analysis was carried out to determine the lattice parameters of the crystal. Powder X-ray diffraction pattern was recorded and indexed for the structural confirmation. The crystalline quality was confirmed by HRXRD. The presence of functional group in the compound has been confirmed by FTIR analysis. UV-Visible transmission spectrum has been recorded to determine the cut-off wavelength region of the crystal. The Second Harmonic Generation of BNMD crystal was confirmed by Kurtz-Perry powder method using Nd:YAG laser and found to be 0.59 times that of KDP. The dielectric response of the crystal was also investigated and reported. The microhardness study reveals that the hardness number (Hv) increases with load. From the values of work hardening coefficients, it was concluded that BNMD crystal belong to the category of soft materials. Thermal studies were performed using differential thermal analysis (DTA).