Fluorescent Properties of a Hybrid Cadmium Sulfide-Dendrimer Nanocomposite and its Quenching with Nitromethane

A fluorescent hybrid cadmium sulphide quantum dots (QDs) dendrimer nanocomposite (DAB-CdS) synthesised in water and stable in aqueous solution is described. The dendrimer, DAB-G5 dendrimer (polypropylenimine tetrahexacontaamine) generation 5, a diaminobutene core with 64 amine terminal primary groups. The maximum of the excitation and emission spectra, Stokes’ shift and the emission full width of half maximum of this nanocomposite are, respectively: 351, 535, 204 and 212 nm. The fluorescence time decay was complex and a four component decay time model originated a good fit (χ = 1.20) with the following lifetimes: τ ₁ = 657 ps; τ ₂ = 10.0 ns; τ ₃ = 59.42 ns; and τ ₄ = 265 ns. The fluorescence intensity of the nanocomposite is markedly quenched by the presence of nitromethane with a dynamic Stern-Volmer constant of 25 M⁻¹. The quenching profiles show that about 81% of the CdS QDs are located in the external layer of the dendrimer accessible to the quencher. PARAFAC analysis of the excitation emission matrices (EEM) acquired as function of the nitromethane concentration showed a trilinear data structure with only one linearly independent component describing the quenching which allows robust estimation of the excitation and emission spectra and of the quenching profiles. This water soluble and fluorescent nanocomposite shows a set of favourable properties to its use in sensor applications.     

Photoluminescence of fluoroacrylate polymers impregnated with Eu(bta)<Subscript>3</Subscript> using supercritical CO<Subscript>2</Subscript>

Optical properties (photoluminescence and absorption) of Eu(bta)₃(B) _n (B = H₂O or 1,10-phenanthroline) polycrystalline powders and fluoroacrylate polymers (FAPs) impregnated with these compounds using supercritical CO₂ (SC CO₂) were investigated. It was established that impregnation of Eu(bta)₃phen into the FAPs using an SC CO₂ solution was difficult to achieve. The type of B (ancillary ligand) and the polymer matrix were shown to influence the temperature quenching of photoluminescence of Eu³⁺ ions in the range 25–100°C. A comparative analysis of quantum yields (λ_ex = 300 and 380 nm) and photoluminescence decay times (λ_ex = 337.1 nm) for Eu(bta)₃B _n and for Eu(bta)₃B _n -doped FAPs was performed.     

Electrical characterization of the [N(CH<Subscript>3</Subscript>)<Subscript>4</Subscript>][N(C<Subscript>2</Subscript>H<Subscript>5</Subscript>)<Subscript>4</Subscript>]ZnCl<Subscript>4</Subscript> compound

The [N(CH₃)₄][N(C₂H₅)₄]ZnCl₄ compound has been synthesized by a solution-based chemical method. The X-ray diffraction study at room temperature revealed an orthorhombic system with P2₁2₁2 space group. The complex impedance has been investigated in the temperature and frequency ranges 420–520 K and 200 Hz–5 MHz, respectively. The grain interior and grain boundary contribution to the electrical response in the material have been identified. Dielectric data were analyzed using the complex electrical modulus M ^* for the sample at various temperature. The modulus plots can be characterized by full width at half height or in terms of a non-exponential decay function ϕ(t) = exp[(−t/τ) ^β ]. The detailed conductivity study indicated that the electrical conduction in the material is a thermally activated process. The variation of the AC conductivity with frequency at different temperatures obeys the Almond and West universal law.     

Luminescence of CaGa<Subscript>2</Subscript>Se<Subscript>4</Subscript>:Eu crystals

We have studied photoluminescence and thermoluminescence (PL and TL) in CaGa₂Se₄:Eu crystals in the temperature range 77–400 K. We have established that broadband photoluminescence with maximum at 571 nm is due to intracenter transitions 4f⁶ 5d–4f⁷ (⁸S_7/2) of the Eu²⁺ ions. From the temperature dependence of the intensity (log I–10³/T), we determined the activation energy (E _a = 0.04 eV) for thermal quenching of photoluminescence. From the thermoluminescence spectra, we determined the trap depths: 0.31, 0.44, 0.53, 0.59 eV. The lifetime of the excited state 4f6 5d of the Eu²⁺ ions in the CaGa₂Se₄ crystal found from the luminescence decay kinetics is 3.8 μsec. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 76, No. 1, pp. 112–116, January–February, 2009.     

Spectroscopic properties of Nd<Superscript>3+</Superscript>:CaNb<Subscript>2</Subscript>O<Subscript>6</Subscript> crystal

The absorption spectra, fluorescence spectrum and fluorescence decay curve of Nd³⁺ ions in CaNb₂O₆ crystal were measured at room temperature. The peak absorption cross section was calculated to be 6.202×10⁻²⁰ cm² with a broad FWHM of 7 nm at 808 nm for E//a light polarization. The spectroscopic parameters of Nd³⁺ ions in CaNb₂O₆ crystal have been investigated based on Judd-Ofelt theory. The parameters of the line strengths Ω _t are Ω ₂=5.321×10⁻²⁰ cm²,Ω ₄=1.734×10⁻²⁰ cm²,Ω ₆=2.889×10⁻²⁰ cm². The radiative lifetime, the fluorescence lifetime and the quantum efficiency are 167 μs, 152 μs and 91%, respectively. The fluorescence branch ratios are calculated to be β ₁=36.03%,β ₂=52.29%,β ₃=11.15%,β ₄=0.533%. The emission cross section at 1062 nm is 9.87×10⁻²⁰ cm².     

Structure,thermal properties,conductivity and electrochemical stability of di-urethanesil hybrids doped with LiCF<Subscript>3</Subscript>SO<Subscript>3</Subscript>

Variable chain length di-urethane cross-linked poly(oxyethylene) (POE)/siloxane hybrid networks were prepared by application of a sol-gel strategy. These materials, designated as di-urethanesils (represented as d-Ut(Y′), where Y′ indicates the average molecular weight of the polymer segment), were doped with lithium triflate (LiCF₃SO₃). The two host hybrid matrices used, d-Ut(300) and d-Ut(600), incorporate POE chains with approximately 6 and 13 (OCH₂CH₂) repeat units, respectively. All the samples studied, with compositions ∞ > n ≥ 1 (where n is the molar ratio of (OCH₂CH₂) repeat units per Li⁺), are entirely amorphous. The di-urethanesils are thermally stable up to at least 200 °C. At room temperature the conductivity maxima of the d-Ut(300)- and d-Ut(600)-based di-urethanesil families are located at n = 1 (approximately 2.0 × 10⁻⁶ and 7.4 × 10⁻⁵ Scm⁻¹, respectively). At about 100 °C, both these samples also exhibit the highest conductivity of the two electrolyte systems (approximately 1.6 × 10⁻⁴ and 1.0 × 10⁻³ Scm⁻¹, respectively). The d-Ut(600)-based xerogel with n = 1 displays excellent redox stability.     

Optical spectra and excited state relaxation dynamics of Sm<Superscript>3+</Superscript> in Gd<Subscript>2</Subscript>SiO<Subscript>5</Subscript> single crystal

Single crystals of gadolinium orthosilicate Gd₂SiO₅ containing 0.5 at% and 5 at% of Sm³⁺ were grown by the Czochralski method. Optical absorption spectra, luminescence spectra and luminescence decay curves were recorded for these systems at 10 K and at room temperature. Comparison of optical spectra recorded in polarized light revealed that the anisotropy of this optically biaxial host affects the intensity distribution within absorption and emission bands related to transitions between multiplets rather than the overall band intensity. It has been found that among four bands of luminescence related to the ⁴G_5/2→⁶H_J (J=5/2–11/2) transitions of Sm³⁺ in the visible and near infrared region the ⁴G_5/2 →⁶H_7/2 one has the highest intensity with a peak emission cross section of 3.54×10⁻²¹ cm² at 601 nm for light polarized parallel to the crystallographic axis c of the crystal. The luminescence decay curve recorded for Gd₂SiO₅:0.5 at% Sm³⁺ follows a single exponential time dependence with a lifetime 1.74 ms, in good agreement with the ⁴G_5/2 radiative lifetime τ _rad=1.78 ms calculated in the framework of Judd-Ofelt theory. Considerably faster and non-exponential luminescence decay recorded for Gd₂SiO₅:5 at% Sm³⁺ sample was fitted to that predicted by the Inokuti-Hirayama theory yielding the microparameter of Sm³⁺–Sm³⁺ energy transfer C _da=1.264×10⁻⁵² cm⁶×s⁻¹.     

Current status of astronomical observations on possible cosmological variations of the proton-to-electron mass ratio μ=m<Subscript>p</Subscript>/m<Subscript>e</Subscript>

Astronomical constraints on a possible cosmologicalvariation of the proton-to-electron mass ratio μ=m_p/m_e are discussed. The analysis of H₂ lines observed in thespectra of distant quasars Q 0405-443 (z_em=3.02) andQ 0347-383 (z_em=3.22) is performed [1] using, partly, very precise values of H₂ frequencies from new laboratorymeasurements [2] and sensitivity coefficients from newaccurate calculations [2,3]. A possibleμ-variation of Δμ/ μ= (2.0±0.6)×10^-5over 12 Gyr is not excluded. However, the discussion of systematicerrors show that some may well be underestimated. Thus, the abovevalue should be treated as the most stringent limit the cosmologicalvariation of μ at z≈2.6 - 3.0 (12 Gyr ago).     

Characterization of channel waveguides in Pr:YLiF<Subscript>4</Subscript> crystals fabricated by direct femtosecond laser writing

Single tracks and pairs of tracks are written in the volume of Pr-doped LiYF₄-crystals using tightly focused femtosecond laser radiation (λ=1045 nm, τ _p=400–500 fs, f=0.1–1 MHz). Waveguiding between the tracks is demonstrated and optimized by varying the distance between the tracks and the laser writing conditions. The stress-induced guiding mechanism is explained based on TEM, interference microscopy, near-field and far-field measurements. It is shown that the single-crystalline material is getting poly-crystalline under femtosecond laser irradiation. By measuring the lifetime of the ³P₁→³H₅ transition and the emission spectrum at excitation with λ=444 nm, no influence on these properties of the guided light is observed. This possibly enables the realization of a channel waveguide laser in the visible spectral range.     

Reductive Fluorescence Quenching of the Photoexcited Free Base <Emphasis Type="Italic">meso</Emphasis>-Tetrakis (Pentafluorophenyl) Porphyrin by Amines

Steady state and time resolved fluorescence quenching behaviors of meso-Tetrakis (pentafluorophenyl) porphyrin (H₂F₂₀TPP) in presence of different aliphatic and aromatic amines have been executed in homogeneous dichloromethane (DCM) solution. At room temperature in DCM, free base (H₂F₂₀TPP) shows fluorescence with two distinct peaks at 640 and 711 nm and natural lifetime τ _f = 9.8 ns which are very similar to that of meso-tetraphenyl porphyrin (TPP). Unlike TPP, addition of both aliphatic and aromatic amines to a solution containing H₂F₂₀TPP results in an efficient decrease in fluorescence intensity without altering the shape and peak position of fluorescence emission. Upon addition of amines there was no change in optical absorption spectra of H₂F₂₀TPP. The fluorescence quenching rate constants ranged from 1 × 10⁹ to 4 × 10⁹ s⁻¹, which are one order below to the diffusion control limit, and temperature dependent quenching rate constants yield the activation energies which are found to be order of 0.1 eV. Femto second transient absorption studies reveal the existence of amine cation radical and porphyrin anion radicals with very short decay time (15 ps). The fluorescence quenching reaction follows Stern–Volmer kinetics. Steady state and time-resolved data are interpreted within general kinetic scheme of Marcus semi-classical model which attributes bimolecular electron transfer process between amines and the lowest excited singlet state of H₂F₂₀TPP. Calculated internal reorganization energies are found to be in between 0.04 and 0.22 ev. Variation of electron transfer rate as function of free energy change (∆G⁰) points the ET reactions in the present systems are in Marcus normal region. This is the first example of reductive fluorescence quenching of free base neutral porphyrins in homogeneous organic solvent ever known.     

The Role of the Eu<Superscript>3+</Superscript> Concentration on the SrMoO<Subscript>4</Subscript>:Eu Phosphor Properties: Synthesis,Characterization and Photophysical Studies

SrMoO₄ doped with rare earth are still scarce nowadays and have attracted great attention due to their applications as scintillating materials in electro-optical like solid-state lasers and optical fibers, for instance. In this work Sr_1−xEu_xMoO₄ powders, where x = 0.01; 0.03 and 0.05, were synthesized by Complex Polymerization (CP) Method. The structural and optical properties of the SrMoO₄:Eu³⁺ were analyzed by powder X-ray diffraction patterns, Fourier Transform Infra-Red (FTIR), Raman Spectroscopy, and through Photoluminescent Measurements (PL). Only a crystalline scheelite-type phase was obtained when the powders were heat-treated at 800 °C for 2 h, 2θ = 27.8° (100% peak). The excitation spectra of the SrMoO₄:Eu³⁺ (λ_Em. = 614 nm) presented the characteristic band of the Eu^3 + 5L₆ transition at 394 nm and a broad band at around 288 nm ascribed to the charge-transfer from the O (2p) state to the Mo (4d) one in the SrMoO₄ matrix. The emission spectra of the SrMoO₄:Eu³⁺ powders (λ_Exc. = 394 and 288 nm) show the group of sharp emission bands among 523–554 nm and 578–699 nm, assigned to the ⁵D₁→⁷F_{0,1and 2} and ⁵D₀→⁷F_{0,1,2,3 and 4}, respectively. The band related to the ⁵D₀→⁷F₀ transition indicates the presence of Eu³⁺ site without inversion center. This hypothesis is strengthened by the fact that the band referent to the ⁵D₀→⁷F₂ transition is the most intense in the emission spectra.     

The determination of <Emphasis Type="Italic">α</Emphasis><Subscript><Emphasis Type="Italic">S</Emphasis></Subscript> from <Emphasis Type="Italic">τ</Emphasis> decays revisited

We revisit the determination of α _S (m _τ ²) using a fit to inclusive τ hadronic spectral moments in light of (1) the recent calculation of the fourth-order perturbative coefficient K ₄ in the expansion of the Adler function, (2) new precision measurements from BABAR of e⁺e⁻ annihilation cross sections, which decrease the uncertainty in the separation of vector and axial-vector spectral functions, and (3) improved results from BABAR and Belle on τ branching fractions involving kaons. We estimate that the fourth-order perturbative prediction reduces the theoretical uncertainty, introduced by the truncation of the series, by 20% with respect to earlier determinations. We discuss to some detail the perturbative prediction of two different methods: fixed-order perturbation theory (FOPT) and contour-improved perturbative theory (CIPT). The corresponding theoretical uncertainties are studied at the τ and Z mass scales. The CIPT method is found to be more stable with respect to the missing higher order contributions and to renormalization scale variations. It is also shown that FOPT suffers from convergence problems along the complex integration contour. Nonperturbative contributions extracted from the most inclusive fit are small, in agreement with earlier determinations. Systematic effects from quark-hadron duality violation are estimated with simple models and found to be within the quoted systematic errors. The fit based on CIPT gives α _S (m _τ ²)=0.344±0.005±0.007, where the first error is experimental and the second theoretical. After evolution to M _Z we obtain α _S (M _Z ²)=0.1212±0.0005±0.0008±0.0005, where the errors are respectively experimental, theoretical and due to the evolution. The result is in agreement with the corresponding N³LO value derived from essentially the Z width in the global electroweak fit. The α _S (M _Z ²) determination from τ decays is the most precise one to date.     

Steady State and Time-Resolved Fluorescence Studies of a Hemagglutinin from Moringa oleifera

The saccharide binding and conformational characterization of a hemagglutinin, a low molecular weight protein from the seeds of Moringa oleifera was studied using steady state and time resolved fluorescence. The lectin binds sugars LacNAc (K _a = 1380 M⁻¹) and fructose (K _a = 975 M⁻¹), as determined by the fluorescence spectroscopy. It has a single tryptophan per monomer which is exposed on the surface and is in a strong electropositive environment as revealed by quenching with iodide. Quenching of the fluorescence by acrylamide involved both static (K _s = 0.216 M⁻¹) and collisional (K _sv = 8.19 M⁻¹) components. The native protein showed two different lifetimes, τ ₁ (1.6 ns) and τ ₂ (4.36 ns) which decrease and get converted into a single one, (2.21 ns) after quenching with 0.15 M acrylamide. The bimolecular quenching constant, k _q was 7.55 × 10¹¹ M⁻¹ s⁻¹. ANS binding studies showed that the native protein has exposed hydrophobic patches which get further exposed at extreme acidic or alkaline pH. However, they get buried in the interior of the protein in presence of 1 M GdnHCl or urea.     

Electrical properties,equivalent circuit,and dielectric relaxation studies on [(C<Subscript>3</Subscript>H<Subscript>7</Subscript>)<Subscript>4</Subscript>N]<Subscript>2</Subscript>Cd<Subscript>2</Subscript>Cl<Subscript>6</Subscript> polycrystalline

The Ac electrical conductivity and the dielectric relaxation properties of the [(C₃H₇)₄N]₂Cd₂Cl₆ polycrystalline sample have been investigated by means of impedance spectroscopy measurements over a wide range of frequencies and temperatures, 209 Hz–5 MHz and 361–418 K, respectively. The purpose is to make a difference between the electrical and dielectric properties of the polycrystalline sample and single crystal. Besides, a detailed analysis of the impedance spectrum suggests that the electrical properties of the material are strongly temperature-dependent. Plots of (Z" versus Z') are well fitted to an equivalent circuit model consisting of a series combination of grains and grains boundary elements. Moreover, the temperature dependence of the electrical conductivity in the different phases follows the Arrhenius law and the frequency dependence of σ (ω) follows the Jonscher’s universal dynamic law. Furthermore, the modulus plots can be characterized by full width at half height or in terms of a nonexperiential decay function φ(t) = exp(t/t)^β. Finally, the imaginary part of the permittivity constant is analyzed with the Cole–Cole formalism.     

Dynamics of Bacteriophage R17 Probed with a Long-Lifetime Ru(II) Metal-Ligand Complex

The metal-ligand complex, [Ru(2,2′-bipyridine)₂(4,4′-dicarboxy-2,2′-bipyridine)]²⁺ (RuBDc), was used as a spectroscopic probe for studying macromolecular dynamics. RuBDc is a very photostable probe that possesses favorable photophysical properties including long lifetime, high quantum yield, large Stokes’ shift, and highly polarized emission. To further show the usefulness of this luminophore for probing macromolecular dynamics, we examined the intensity and anisotropy decays of RuBDc when conjugated to R17 bacteriophage using frequency-domain fluorometry with a blue light-emitting diode (LED) as the modulated light source. The intensity decays were best fit by a sum of two exponentials, and we obtained a longer mean lifetime at 4 °C (<τ> = 491.8 ns) as compared to that at 25 °C (<τ> = 435.1 ns). The anisotropy decay data showed a single rotational correlation time, which is typical for a spherical molecule, and the results showed a longer rotational correlation time at 4 °C (2,574.9 ns) than at 25 °C (2,070.1 ns). The use of RuBDc enabled us to measure the rotational correlation time up to several microseconds. These results indicate that RuBDc has significant potential for studying hydrodynamics of biological macromolecules.     

Laser induced breakdown spectroscopy of germane plasma induced by IR CO2 pulsed laser

Laser-induced breakdown spectroscopy (LIBS) in germane (GeH₄), initially at room temperature and pressures ranging from 2 to 10 kPa, was studied using a high-power transverse excitation atmospheric (TEA) CO₂ laser (λ=10.653 μm, τ _FWHM=64 ns and power densities ranging from 0.28 to 5.52 GW cm⁻²). The strong emission spectrum of the generated plasma is mainly due to electronic relaxation of excited Ge, H and ionic fragments Ge⁺, Ge²⁺ and Ge³⁺. The weak emission is due to molecular bands of H₂. Excitation temperatures of 8100±300 K and 23,500±2500 K were estimated by Ge atomic and Ge⁺ singly ionized lines, respectively. Electron number densities of the order of (0.7–6.2)×10¹⁷ cm⁻³ were deduced from the Stark broadening of several atomic Ge lines. The characteristics of the spectral emission intensities from different species have been investigated as functions of the germane pressure and laser irradiance. Optical breakdown threshold intensities in germane at 10.653 μm have been determined. The mechanism of initiation of the laser-induced plasma in germane has been analyzed.     

Influence of storage time on laser cleaning of SiO<Subscript>2</Subscript> on Si

The influence of the ‘storage time’ τ_s on the threshold fluence φ_cl and the efficiency in dry laser cleaning is investigated. τ_s denotes the time between the deposition of particles and the cleaning. As a model system we employed silica spheres with diameters of 500 nm and 1500 nm on commercial silicon wafers and single-pulse KrF excimer laser radiation (τ_FWHM=28 ns). For the 1500-nm silica spheres, φ_cl was found to increase from about 65 mJ/cm² to 125 mJ/cm² for storage times of 4 h and 362 h, respectively. For 500-nm silica spheres the increase in the threshold fluence was less than 20% for storage times up to 386 h. Received: 12 July 2002 / Accepted: 12 July 2002 / Published online: 29 January 2003 RID="*" ID="*"Corresponding author. E-mail:dieter.baeurle@jku.at     

Spectroscopic properties of Er<Superscript>3+</Superscript> ions in LiNbO<Subscript>3</Subscript> crystals codoped with HfO<Subscript>2</Subscript>

The results of the spectroscopic analysis of transition strengths for Er³⁺ ions in a series of Hf:Er:LiNbO₃ crystals with variable Hf content and fixed Er content are reported. Unpolarized UV-VIS-NIR absorption spectra, upconversion fluorescence spectra excited at 800 nm, and microsecond time-resolved spectra excited at 400 nm and 800 nm by 800 nm femtosecond laser were measured at room temperature. The HfO₂ incorporation has influence on Er³⁺ radiative lifetimes, and fluorescence branching ratios. For Hf(4 mol %):Er(1 mol %):LiNbO₃, Ω₂=2.63×10^-20 cm², Ω₄=2.86×10^-20 cm², and Ω₆=0.72×10^-20 cm². Ω₂<Ω₄ is contrary to the Er³⁺ general trend of Ω₂>Ω₄>Ω₆ when the Hf content is below its threshold concentration. In addition, the sum of Ω increases with the Hf content when the HfO₂ content below 6 mol % is unfamiliar. The upconversion mechanism is discussed in this work. PACS 71.20.Eh; 77.84.Dy; 42.62.Fi; 42.65.Ky     

Europium(III) Concentration Effect on the Spectroscopic and Photoluminescent Properties of BaMoO4:Eu

BaMoO₄:Eu (BEMO) powders were synthesized by the polymeric precursor method (PPM), heat treated at 800 °C for 2 h in a heating rate of 5 °C/min and characterized by powder X-ray diffraction patterns (XRD), Fourier Transform Infra-Red (FTIR) and Raman spectroscopy, besides room temperature Photoluminescence (PL) measurements. The emission spectra of BEMO samples under excitation of 394 nm present the characteristic Eu³⁺ transitions. The relative intensities of the Eu³⁺ emissions increase as the concentration of this ion increases from 0.01 to 0.075 mol, but the luminescence is drastically quenched for the Ba_0.855Eu_0.145MoO₄ sample. The one exponential decay curves of the Eu^{3+ 5}D₀→⁷F₂ transition, λ _exc = 394 nm and λ _em = 614 nm, provided the decay times of around 0.54 ms for all samples. It was observed a broadening of the Bragg reflections and Raman bands when the Eu⁺³ concentration increases as a consequence of a more disordered material. The presence of MoO₃ and Eu₂Mo₂O₇ as additional phases in the BEMO samples where observed when the Eu³⁺ concentration was 14.5 mol%.     

Electro-optic properties of epitaxial Sr<Subscript>0.6</Subscript>Ba<Subscript>0.4</Subscript>Nb<Subscript>2</Subscript>O<Subscript>6</Subscript> films grown on MgO substrates using Li<Subscript>x</Subscript>Ni<Subscript>2-x</Subscript>O buffer layer

Textured Li_xNi_2-xO (LNO) thin films have been fabricated on (001)MgO substrates by pulsed laser deposition technique. The as-deposited LNO films shows a conductivity of 2.5×10^-3 Ω m and possess a transmittance of about 35% in the visible region. Subsequent deposition of Sr_0.6Ba_0.4Nb₂O₆ (SBN60) thin film on these LNO-coated MgO substrates resulted in a textured SBN layer with a 〈001〉 orientation perpendicular to the substrate plane. Phi scans on the (221) plane of the SBN layer indicated that the films have two in-plane orientations with respect to the substrate. The SBN unit cells were rotated in the plane of the film by ± 8.2° as well as ± 45° with respect to the LNO/MgO substrate. Besides the highly (00l)-orientation, the SBN films also exhibited a dense microstructure as shown by scanning electron microscopy. The electro-optic coefficient (r₃₃) of the SBN film was measured to be 186 pm/V. On the basis of our results, we have demonstrated that the LNO film can be used as a buffer layer as well as a transparent bottom electrode for waveguide applications. The SBN/LNO heterostructure is also a suitable candidate for integrated electro-optics devices. PACS  42.79.Gn; 42.82.Et; 78.20.Ci