UV Vis IR Research Articles

Nano-silver enhanced luminescence of Eu3+-doped lead tellurite glass

Eu3+-doped lead sodium tellurite glasses containing silver nanoparticles (NPs) were synthesized by melt-quenching technique and annealed for different time intervals at above the glass transition temperature. The glasses were characterized by UV–Vis–IR absorption, photoluminescence spectroscopy and transmission electron microscope imaging. Four absorption peaks of Eu3+ ion were observed due to transitions from ground state to different excited states in 400–600nm region. The surface plasmon resonance (SPR) peak of silver NPs was probed at 632nm. Five emission lines were recorded at 568, 587, 614, 650 and 704nm which were intensified in the order of ∼1.9 times for heat-treated samples containing silver NPs. The average size of NPs was estimated to be ∼10nm. Different mechanisms for interaction of light with metal and luminescent ions are discussed. Such enhancements are attributed to the strong local electric field induced by SPR of silver NPs as the major factor, and energy transfer from surface of silver NP to Eu3+ ion. The glasses show promising properties for optical applications.

Synthesis of Metal Complexes of Schiff Bases and their Nematicidal Activity Against Root Knot Nematode Meloidogyne incognita

Six metal complexes were synthesized from Cd (II), Mn (II) and Zn (II) chloride and ligands 2-((3- nitrophenylimino)methyl)phenol (HL1) and 2-((4-nitrophenylimino)methyl)phenol (HL2) in 1:2 M ratio. Microanalytical data, UV-Visible spectral data, magnetic susceptibility, IR, 1HNMR, 13CNMR, mass and molar conductance measurements were used to characterize the structure of complexes. The complexes were found to be non electrolytic on the basis of molar conductance studies. The Schiff bases and their metal complexes had also been screened for their antinemic activity against root knot nematode, Meloidogyne incognita. Complexes have shown significant antinemic activity than their corresponding Schiff bases.

Synthesis and Characterization of Se-doped ZnO Nanoparticles by Electrochemical Method: Photodegradation Kinetics of Indigo Carmine Dye and Study of Antimicrobial, Antimitotic Activities of Se-doped ZnO Nanoparticles

In the past few decades selenium nanoparticles have received a considerable importance because of its effective biological applications. Therefore, nano-structured Se-doped ZnO photocatalyst has been synthesized by electrochemical method, which is a simple and an inexpensive method. The characterization techniques included are UV-Visible spectroscopy, IR spectroscopy, SEM and X-ray diffraction techniques. From UV-Vis spectroscopy and by using Tauc plot the band gap energy of Se-doped ZnO nanoparticles is calculated and is found to be 2.6eV. The IR spectra showed the peak at 427 cm-1 for ZnO bonds and peaks at 518cm-1, 612cm-1, 727cm-1 and 1373cm-1 correspond to the presence of Se-ZnO bending and stretching vibrations. From the XRD data and with the help of Williamson-Hall plot the crystalline size is calculated and it is found to be ~25.5 nm. The photocatalytic activity of the synthesized Se-doped ZnO nanoparticles was investigated by the kinetics of degradation of Indigo carmine dye. The degradation efficiency of Se-doped ZnO was found to be ~96%. The antimicrobial and antimitotic activities were evaluated for the synthesized ZnO and Se-doped ZnO nanoparticles against the control.

On construction of lead coordination polymers derived from N′-(2-hydroxybenzylidene)nicotinohydrazide via covalent and non-covalent interactions

Lead(II) and lead(IV) coordination polymers with N′-(2-hydroxybenzylidene)nicotinohydrazide have been synthesized from lead(II) salts, and subsequently characterized by solid-state UV‒Vis‒IR spectroscopy, thermal analysis, and powder and single-crystal X-ray diffraction techniques. The compounds crystallize in the same space group but differ in the oxidation state of lead, composition, conformation of the organic ligand, its charge, and tautomeric form. The coordination network is propagated by the hydrazone anion in the lead(II) metal-organic framework catena-[(μ2-N-((2-oxidophenyl)methylidene)pyridine-3-carbohydrazonoato-N:N′,O,O′)-lead(II) (1) and by nitrate in a one-dimensional lead(IV) coordination polymer catena-(μ2-nitrato-O,O)-(nitrato-O,O′)-(salicylaldehydeisonicotinoylhydrazonato-N,N′,O)-lead(IV) nitrate (2). The formation of metal-organic framework of 1 is affected by Pb···π interactions.

Synthesis of Niobium Doped ZnO Nanoparticles by Electrochemical Method: Characterization, Photodegradation of Indigo Carmine Dye and Antibacterial Study

Niobium doped Zincoxide nanoparticles has been synthesized through electrochemical method and characterized by UV-Visible spectroscopy, IR Spectroscopy, SEM, XRD, ICPMS and EDAX data. The UV-Visible spectroscopy result reveals that the band gap energy of ZnO/Nb2O5 nanoparticles to be 3.8 eV. The XRD results show that the crystallite size is to be 31.9 nm. The ICPMS data indicate the presence of 3,3461,328 counts of 93 Nb and 577,906,390 counts of 66 Zn. An improvement in the photocatalytic degradation of Indigocarmine dye (IC) in comparison to commercially available pure ZnO was observed. The photodegradation efficiency for ZnO/Nb2O5 and ZnO were found to be 97.4% and 52.1% respectively. The enhancement in photocatalytic activity of ZnO/ Nb2O5 was ascribed to the extended light absorption range and suppression of electron hole pair recombination upon Nb loading. The antibacterial activity of ZnO/Nb2O5 nanoparticles was investigated. These particles were shown to have an effective bactericide.

Influences of synthesis conditions on chemical composition of Cu2ZnSnS4 nanocrystals prepared by one pot route

In present work, the Cu2ZnSnS4 (CZTS) nanocrystals (NCs) were successfully synthesized via a rapid and simple one pot route. The influences of the reaction temperature and time on the chemical composition were first investigated in detail by energy dispersive X-ray spectroscopy. Meanwhile, the variations of the structural, morphological and optical properties of the as-synthesized CZTS NCs were analyzed by combining with the changes of the chemical composition via x-ray diffraction, field emission scanning electron microscopy (FE-SEM) and UV–Vis–IR spectrophotometer, respectively. It was found that the reaction temperature and time had significant impacts on the element composition, especially for the variations of Zn and Sn; and the variations of structure, morphology and band gap energy were closely linked with the changes of Zn and Sn. The characterization results of the as-synthesized CZTS NCs, under the optimal synthesis condition (250 °C, 1 h), were shown as following: the compositional ration was near stoichiometric (Zn/Sn = 0.81, Cu/(Zn + Sn) = 0.97, S/(Cu + Zn + Sn) = 1.07), the average size of NCs was 19.98 nm, the size of aggregation nanoparticles was in the range of 200–500 nm, and the band gap energy was 1.5 eV. All results suggested that the as-synthesized CZTS NCs were good light absorption layer material for thin film solar cell.

Synthesis, structure, and characterization of a new rubidium cadmium borate: RbCdB3O6

A new ternary borate, RbCdB3O6 has been synthesized by solid-state reaction and its structure was determined by single-crystal X-ray diffraction. It crystallizes in the monoclinic space group C2/c, and in its crystal structure, RbO10 polyhedra and B3O6 rings comprise a three dimensional (3D) framework containing tunnels viewing along [101] direction in which Cd atoms are located to balance the charge. A comparison of the structures of RbCdB3O6, α-BaB2O4 and β-BaB2O4 is presented. The IR, UV–Vis-IR absorption spectra and the thermal properties of RbCdB3O6 have also been reported. The electronic structure and birefringence have been calculated by the first-principle method based on the density-functional theory.

Molybdenum Oxides: Wide‐Spectral Photoresponse of Black Molybdenum Oxide Photodetector via Sub‐Bandgap Electronic Transition (Advanced Optical Materials 10/2013)

On page 699, C.-S. Lee, M.-F. Lo, and co-workers report a black-colored MoO3 obtained by vacuum annealing of typical transparent MoO3. The black color is caused by splitting of the original wide bandgap into two regions of 1.8 and 1.0 eV widths. This enables IR absorption and the fabrication of a black MoO3-based photodetector with response across the full UV–visible–IR spectral range.

Synthesis, structures, optical properties and electronic structures of two mixed metal borates MBaB5O9 (M=Na, K)

Two ternary borates, MBaB5O9 (M = Na, K) have been synthesized by the flux method. Single-crystal X-ray diffraction analysis revealed that they crystallize in the same space group P21/c (No. 14). In their crystal structures, the basic building blocks are the B5O9 double rings, which are further linked by corner-sharing to form a two-dimension (2D) infinite corrugated ∞[B5O9]3− layer. However, since the 2D ∞[B5O9]3− layers possess the different arrangement in NaBaB5O9 and KBaB5O9, they are not isostructural. In addition, the UV–Vis–IR diffuse reflectance spectra exhibit that they have the relatively wide band gaps, 4.78 eV for NaBaB5O9 and 3.65 eV for KBaB5O9. The DSC analysis suggests that NaBaB5O9 melts congruently. And the first-principle theoretical studies are also carried out to aid the understanding of electronic structures and linear optical properties.

KSi2P3: A new layered phosphidopolysilicate (IV)

Abstract A new ternary phosphidopolysilicate (IV), KSi2P3, has been synthesized by high temperature solid state reaction. The compound crystallizes in a new structure type in the monoclinic space group C2/c with a=10.1327(5) A, b=10.1382(5) A, c=21.1181(10) A, β=96.88(0)°, and Z=8. In the structure, all SiP4 tetrahedra are connected with each other by corner-sharing P atoms to form [ Si 2 P 3 ] − ∞ 2 layers, which are stacked along c direction and separated by K+ cations. The two-dimensional structure of KSi2P3 contrasts with those of the two known members in the ternary A/Si/P (A=alkali metal) system, namely Na5SiP3 (zero-dimensional) and K2SiP2 (one-dimensional), which contains less amount of Si. The band gap deduced from UV–vis–IR diffuse reflectance spectrum is 1.72 eV.

Wide‐Spectral Photoresponse of Black Molybdenum Oxide Photodetector via Sub‐Bandgap Electronic Transition

Black molybdenum oxide (BMO) is prepared by annealing transparent MoO3. While recent efforts on other black oxides show that their black colour contributes little towards visible light harvesting, the presented BMO shows much-enhanced photoresponse over the UV–vis–IR regions. By sandwiching the BMO with suitable charge transporting layers, a photodetector with spectral response from UV to IR is demonstrated. As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re-organized for online delivery, but are not copy-edited or typeset. Technical support issues arising from supporting information (other than missing files) should be addressed to the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Concentration dependent luminescence quenching of Er3+-doped zinc boro-tellurite glass

Understanding the mechanism of luminescence quenching in rare earth doped tellurite glass is an important issue. The Er3+-doped boro-tellurite glasses with compositions 30B2O3+10ZnO+(60−x)TeO2+xEr2O3 (where x=0, 0.5, 1, 1.5 and 2mol%) were prepared by melt quenching method. Structural and optical properties of the proposed glasses were characterized using XRD, FTIR, density, UV–vis-IR absorption and PL spectroscopy. The amorphous nature of these glasses was confirmed by XRD technique. The IR-spectrum reveals five absorption bands assigned to different B–O and Te–O vibrational groups. UV–vis-IR absorption spectrum exhibits seven absorption bands at 6553, 10,244, 12,547, 15,360, 19,230, 20,661 and 22,522cm−1 corresponding to 4I13/2, 4I11/2, 4I9/2, 4F9/2, 2H11/2, 4F7/2 and 4F3/2 excited states of Er3+ ion respectively. The optical band gap energy (Eopt) corresponding to the direct and indirect allowed transitions decreased, while the Urbach energy and cut-off wavelengths are increased by the introduction of Er3+ ions. The refractive index, density and phonon cut-off edge of the samples are increased and the molar volume decreased with the further addition of dopants. The Judd–Ofelt parameter (Ω2) decreased from 5.73 to 3.13×10−20cm2 with the increase of erbium ions concentration from 0.5 to 2mol%. The PL spectra show green emissions for the transition from 2H11/2 and 4S3/2 excited states to 4I15/2 ground state, which show strong quenching due to the addition of Er3+ ions.

Opto-electronic properties of molybdenum doped indium tin oxide nanostructured thin films prepared via sol–gel spin coating

Abstract Molybdenum-doped indium tin oxide thin films were synthesized using sol–gel spin coating technique. The influence of different molybdenum-dopant contents on the electrical, optical, structural, and morphological properties of the films were characterized by means of four point probe, UV–Vis–IR spectroscopy, X-ray diffraction, field emission scanning electron microscopy, and atomic force microscopy. For this purpose, addition of different molybdenum contents with tin at a fixed 6 at% is considered as the first approach. For the second and third approaches, different molybdenum-doping contents were added at a constant atomic ratios of In:Sn=94:6 and In:Sn=95:5, respectively. Obtained results indicate that minimum resistivity of 22.3×10 −3 Ω cm and optical transmittance of more than 80% in the UV–Vis–IR region with a band gap of 3.83 eV were achieved for the films prepared through the first approach at molybdenum and tin doping contents of 0.5 and 5.5 at%, respectively. X-ray diffraction analysis confirmed the formation of cubic bixbyite structure of indium oxide and rhombohedral structure of indium tin oxide for molybdenum-doped films with small shift in a major peak position to lower diffraction angles with the addition of molybdenum. Field emission scanning electron microscopy micrographs do not show any specific changes in grain size of the films with addition of molybdenum beside tin. Atomic force microscopy studies show that the addition of molybdenum at optimum content to indium tin oxide films results in the formation of films with compact surface and less average roughness than the undoped indium tin oxide films.

The Effect of Substrate Temperatures on CdS Film Prepared by Thermal Evaporation

A suitable deposition method of CdS is necessary for the high performance CIGS(Cu(In0.7Ga0.3)Se2.2) solar cells. In this paper, CdS films were deposited onto glass substrates at the substrate temperture of 50°C、100°C、150°C by thermal evaporation, the effect of the temperature were presented. CdS film deposited at substrate temperture of 150°C was annealed at 150°C for 30min. All films were characterized for their morphology, structure and optical property using scanning electron microscope(SEM), X-ray diffractometer(XRD) and UV–VIS–IR transmittance respectively.The quantum efficiency of the fabricated solar cells with annealed CdS buffer layer was also enhanced at short wavelength. This new method leads to the improved performance of CIGS solar cells and also simplify the whole fabrication technology.

Growth and design of novel nonlinear optical material (NLO) ⿿ Glycine barium nitrate potassium nitrate (GBNPN) crystal

A potentially useful semi organic nonlinear optical (NLO) material ⿿ glycine with barium nitrate and potassium nitrate (GBNPN) has been synthesized by slow evaporation technique. Good transparent GBNPN crystals were obtained in a time span of 3 weeks. The grown crystals were characterized by single crystal/powder XRD, UV⿿vis⿿IR absorption, FTIR, thermal analysis and powder SHG measurements have been studied. The grown crystals were thermally stable up to 137.53°C. The GBNPN crystal exhibits second harmonic generation efficiency of about 1.35 times than that of potassium di hydrogen phosphate (KDP). Mechanical properties such as micro hardness (Hv) and Mayer's index, n, have been carried out by indentation method. The refractive index (μ) has been measured by the Brewster's angle method.

Synthesis, crystal structure and optical properties of a new beryllium borate, CsBe4(BO3)3

A novel beryllium borate CsBe4(BO3)3 has been grown in crystals by high-temperature flux method using spontaneous nucleation technique for the first time. The crystal structure of this compound was determined by single crystal X-ray diffraction analysis. It crystallizes in the orthorhombic space group Pnma with lattice parameters a = 8.3914(5) Å, b = 13.3674(7) Å, c = 6.4391(3) Å, Z = 4, V = 722.28(7) Å3. The crystal takes the same structure type as Rb analog based on the units of BO3 triangles and BeO4 tetrahedrons, displaying a three-dimensional tunnel structure with Cs atoms filling in the cages. The IR spectrum confirms the presence of BO3 groups and the UV–vis–IR diffuse reflectance spectrum exhibits this compound has a short UV cut-off edge below 200 nm. Band structures and density of states were calculated.

Characterization and field-effect transistor performance of printed pentacene films prepared by photoconversion of a soluble precursor

6,13-Dihydro-6,13-ethanopentacene-15,16-dione is a soluble precursor of pentacene, which can be converted into pentacene by irradiation in the solid-state. Its photoconversion process in spin-coated films was monitored by UV-visible absorption and IR spectroscopy. A small amount of high-boiling-point additives in the chloroform spin-coating solution promoted photoconversion to obtain high quality films suitable for FETs. The FET mobilities showed a correlation with the additives' boiling points and dissolution abilities, indicating that the retainment of a semidry state during photoconversion is essential to the complete photoconversion. Photoirradiation conditions (irradiation intensity, duration and substrate temperature) were optimized to achieve a field-effect mobility of 0.86 cm2 V−1 s−1, comparable to the performance of vacuum-deposited pentacene films. The prepared films have a partially crystalline morphology different from that of vacuum-deposited films. The high FET mobility of the photoconverted film is attributed to continuously connected grain boundaries arising from partial crystallinity.

Photochemical stability of electrochromic polymers and devices

The stability of fully printed flexible organic electrochromics based on 11 different conjugated polymers is explored from the fundamental chemical degradation level to the operational device level. The photochemical stability of the electrochromic polymers (ECPs) is studied enabling an analysis of the influence that the chemical constitution of the conjugated polymer backbone has on the photochemical stability. Based on changes in the UV-visible absorption and IR spectra, the polymers were categorized into two distinct groups, each with a separate degradation mechanism. During irradiation (1000 W m−2, AM 1.5G) under ambient conditions the majority of the polymers degraded within 4–5 hours. Three polymers showed increased stability with degradation rates from 0.44 to 1.58% per hour measured as loss of absorption. Application of oxygen and UV barrier foils was found to drastically slow the photochemical decomposition of the polymer films, such that after 2200 hours of continuous irradiation the less stable polymer films were degraded 27% on average, while the degradation of the most stable polymer films was immeasurable thus indicating that such materials can be sufficiently stable for device operations for many years under indoor conditions and for a few years under outside conditions. Finally, functioning electrochromic devices (ECDs) were made and the effect of illumination on the response time and optical contrast was established. This report shows that encapsulated electrochromic devices based on flexible barrier substrates exhibit increased stability and are indeed viable in devices such as shading elements, light management systems, displays with low switching speed requirements and signage.

Investigations on opto-electronical properties of DC reactive magnetron sputtered zinc aluminum oxide thin films annealed at different temperatures

In the present study transparent conducting zinc aluminum oxide (ZAO) thin films were prepared by DC reactive magnetron sputtering technique. The films were deposited on glass substrates at 200°C and annealed from 200°C to 500°C. XRD patterns of ZAO films shows (002) diffraction peak of hexagonal wurtzite, meaning that the films have c-axis orientation perpendicular to the substrate. Crystallite size was calculated from X-ray diffraction (XRD) spectra using the Scherrer formula. The surface morphology of the films was observed by field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). The electrical conductivity increases with increase of annealing temperature. The activation energies of conduction were obtained from an Arrhenius equation. The best characteristics of ZAO films have been obtained for the films annealed at 400°C with an average transmittance of 88% and a minimum resistivity of 2.2×10−4Ωcm. The optical band gap, optical constants, and electron concentrations of ZAO films are obtained from UV–vis–IR spectrophotometer data.

Synthesis, crystal structure and DFT analysis of a phenoxo bridged Cu(II) complex and an azide and μ3-O mixed bridged trinuclear Cu(II) complex

One binuclear Cu(II) complex, [Cu2(L1)2(N3)2] (1), and a trinuclear Cu(II) complex, [Cu3(L2)3(μ1,1N3)2](ClO4) (2), of two potentially tridentate NNO-donor Schiff base ligands, [2-(1-(2-(4,6-dimethylpyrimidin-2-yl)hydrazono)ethyl)phenol] (HL1) and [2-((2-(4,6-dimethyl pyrimidin-2-yl) hydrazono) methyl) phenol] (HL2), have been synthesized and characterized by elemental analyses, UV–Vis IR spectroscopy, DFT and single crystal X-ray crystallography. The ligands HL1 and HL2 are [1+1] condensation products of 2-hydrazino-4,6-dimethylpyrimidine with 2-hydroxy acetophenone and salicylaldehyde respectively. In 1, the two Cu(II) centers are bridged by μ-phenoxo groups. In 2, the three Cu(II) centers are held together by two μ1,1 bridging azide ions and a phenoxo oxygen atom which binds the three metal centers and behaves as a μ3-O atom. The geometries of the complexes have been optimized using the UB3LYP level of theory. The calculation confirms that all the copper centers are five coordinate with distorted square pyramidal geometries, which is consistent with the experimental data.