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Thin film materials have been used in semiconductor devices, wireless communications, telecommunications, integrated circuits, rectifiers, transistors, solar cells, lightemitting diodes, photoconductors and light crystal displays, lithography, micro- electromechanical systems (MEMS) and multifunctional emerging coatings, as well as other emerging cutting technologies. The ZnO, CdO and CdZnO thin films were deposited by chemical routes such as chemical bath deposition, spray pyrolysis, Sol-Gel spin coating, electrodeposition, SILAR, chemical vapour deposition, atomic layer deposition, and pulsed vapour deposition are discussed. Furthermore, the ZnO, CdO and CdZnO thin films depend on various preparative parameters such as the molarity, pH of the solution, deposition time, annealing temperature, annealing time, thickness, substrate used and pressure etc are also discussed. [ABSTRACT FROM AUTHOR]

Abstract: Yttrium doped Zinc Oxide (Y x Zn1−x O) thin films deposited at a substrate temperature 400°C. The effect of substrate temperature on the structural, surface morphology, compositional, optical and electrical properties of Y x Zn1−x O thin films was studied. X-ray diffraction studies show that all films are polycrystalline in nature with hexagonal crystal structure having highly textured (002) plane parallel to the surface of the substrate. The structural parameters, such as lattice constants (a and c), crystallite size (D), dislocation density (δ), microstrain (σ) and texture coefficient were calculated for different yttrium doping concentrations (x). High resolution scanning electron microscopy measurements reveal that the surface morphology of the films change from platelet like grains to hexagonal structure with grain size increase due to the yttrium doping. Energy dispersive spectroscopy confirms the presence of Y, Zn and O elements in the films prepared. Optical studies showed that all samples have a strong optical transmittance higher than 70% in the visible range. A slight shift of the absorption edge towards the large wavelengths was observed as the Y doping concentration increased. This result shows that the band gap is slightly decreased from 3.10 to 2.05eV with increase of the yttrium doping concentrations (up to 7.5%) and then slightly increased. Room temperature PL measurements were done and the band-to-band emission energies of films were determined and reported. The complex impedance of the 10%Y doped ZnO film shows two distinguished semicircles and the diameter of the arcs got decreased in diameter as the temperature increases from 70 to 175°C. [Copyright &y& Elsevier]

Highlights: [•] Thin films of Ce doped ZnO were prepared by nebulizer spray pyrolysis technique. [•] Films were deposited at different cerium concentrations 2.5%, 5.0%, 7.5% and 10%. [•] Ce doped ZnO films are found to have more grains along [002] direction. [•] The band gap energy was found to be decreased with the increase of Ce doping. [•] Ce x Zn1−xO films ensure their stability and suitability for gas sensors. [ABSTRACT FROM AUTHOR]

Abstract: Zinc oxide (ZnO) thin films were deposited by nebulizer spray pyrolysis technique with different molar concentrations of 0.05M, 0.10M and 0.15M. The films were characterized by structural, morphological, electrical and optical properties. X-ray diffraction confirms that the all films are polycrystalline in nature with hexagonal crystal structure having preferential orientation along (002) plane and the maximum crystallite size is found to be ∼77nm. The band gap energy increases with molar concentration and reaches a maximum value of 3.2eV at 0.15M. Room temperature photoluminescence measurements were performed and band to band emission energies of ZnO films were determined. High resolution scanning electron microscopy shows the uniform distribution, densely packed grains with a plate like structure of ∼55nm (0.05M). [Copyright &y& Elsevier]

Pure and cadmium doped tin oxide thin films were deposited on glass substrates from aqueous solution of cadmium acetate, tin (IV) chloride and sodium hydroxide by the nebulizer spray pyrolysis (NSP) technique. X-ray diffraction reveals that all films have tetragonal crystalline structure with preferential orientation along (200) plane. On application of the Scherrer formula, it is found that the maximum size of grains is 67nm. Scanning electron microscopy shows that the grains are of rod and spherical in shape. Energy dispersive X-ray analysis reveals the average ratio of the atomic percentage of pure and Cd doped SnO2 films. The electrical resistivity is found to be 102 Ωcm at higher temperature (170°C) and 103 Ωcm at lower temperature (30°C). Optical band gap energy was determined from transmittance and absorbance data obtained from UV–vis spectra. Optical studies reveal that the band gap energy decreases from 3.90eV to 3.52eV due to the addition of Cd as dopant with different concentrations. [ABSTRACT FROM AUTHOR]

Abstract: The cadmium sulfo selenide CdS1−x Se x thin films were chemical bath deposited in aqueous media onto coated glass substrates. As-deposited CdS1−x Se x thin films were annealed at 350°C in air for 30min. The structural, morphological, compositional and optical properties of deposited CdS1−x Se x thin films were studied using X-ray diffractometer (XRD), scanning electron microscopy (SEM), Energy dispersive analysis by X-ray (EDAX), and UV-Vis-NIR spectrophotometer respectively. X-ray diffraction patterns of CdS1−x Se x thin films reveal the polycrystalline nature and hexagonal structure. The microstructural parameters such as crystallite size (D), micro strain (ɛ), and dislocation density were calculated and found to depend on compositions. The surface morphology and grain size are found to be influenced with the annealing temperature. The presence of Cd, S and Se of the CdS1−x Se x thin films and the composition of CdS1−x Se x thin film are estimated by EDAX analysis. The optical transmittance and absorption spectra were recorded in the range 400–2500nm. The band gap of the CdS1−x Se x thin films is found to decrease from 2.5eV to 1.75eV. [Copyright &y& Elsevier]

Abstract: Cadmium sulphide (CdS) thin films were prepared chemical bath deposition technique. The films were doped with copper using the direct method consisting in the addition of a copper salt in the deposition bath of CdS. The doped films were annealed in air, at 250, 300 and 350°C, for 1h. The deposition films were characterized with X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive analysis by X-rays (EDAX) and optical properties of CdS thin films before and after Cu doping. XRD analysis shows that the films are polycrystalline in nature with cubic crystalline structure. The various parameters such as crystallite size, micro strain and dislocation density were evaluated. SEM study shows that the total substrate surface is well covered by uniformly distributed spherical shaped grains. Optical transmittance study shows the presence of direct transition with band gap energy decrease 2.5–2.2eV. [Copyright &y& Elsevier]

Abstract: Thin films of cadmium tin selenide (CdSnSe) have been prepared on glass substrates at different temperatures by the nebulizer spray pyrolysis (NSP) technique using aqueous solutions of cadmium chloride (CdCl2), tin chloride (SnCl2) and sodium selenosulphate (Na2SeSO3). The deposited films were characterized by structural, morphological, compositional, optical and electrical properties. X-ray diffraction studies confirm that the CdSnSe films are polycrystalline in nature having mixed phase (hexagonal+cubic) crystal structure with preferential orientation (102) plane which corresponds to hexagonal crystal structure. Scanning electron microscopy studies reveal that the prepared films are having smooth and uniform surface with dense surface morphology well-covered over the entire substrate surface without any cracks. The UV–vis spectroscopy confirms the formation of good transparent CdSnSe films with an average transmission ∼60% in the visible region. Optical band gap energies of the films are found to be varied from 1.6–1.625eV depending on the substrate temperatures. The temperature dependence of the electrical conductivity during the heat treatment was also studied. The electrical conductivity of the films is found to be in the order of 10−3 Ω-cm−1 and increases with temperature. [Copyright &y& Elsevier]

Abstract: Cadmium selenide (CdSe) thin films have been successfully prepared by the electrodeposition technique on indium doped tin oxide (ITO) substrates with aqueous solutions of cadmium sulphate and selenium dioxide. The deposited films were characterized with X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive analysis by X-rays (EDAX), photoluminescence (PL), UV spectrometry and electrical resistivity measurements. XRD analysis shows that the films are polycrystalline in nature with hexagonal crystalline structure. The various parameters such as crystallite size, micro strain, dislocation density and texture coefficients were evaluated. SEM study shows that the total substrate surface is well covered with uniformly distributed spherical shaped grains. Photoluminescence spectra of films were recorded to understand the emission properties of the films. The presence of direct transition with band gap energy 1.75eV is established from optical studies. The electrical resistivity of the thin films is found to be 106 Ωcm and the results are discussed. [Copyright &y& Elsevier]

Abstract: Tin sulfide (SnS) thin films have been deposited by electrodeposition using potentiostaic method on indium doped tin oxide (ITO) coated glass substrates from aqueous solution containing SnCl2·2H2O and Na2S2O3 at various potentials. Good quality thin films were obtained at a cathodic potential −1000mV versus saturated calomel electrode (SCE). The deposited films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared (FTIR). X-ray diffraction analysis shows that the crystal structure of SnS thin films is orthorhombic with preferential orientation along 〈021〉 plane. Microstructural parameters such as crystallite size, micro strain, and dislocation density are calculated and found to depend upon cathodic potentials. SEM studies reveal that the SnS films exhibited uniformly distributed grains over the entire surface of the substrate. The optical transmittance studies showed that the direct band gap of SnS is 1.1eV. FTIR was used to further characterize the SnS films obtained at various potentials. [Copyright &y& Elsevier]

Abstract: Cd1−x Zn x S (0≤ x ≤1) thin films have been deposited by chemical bath deposition method on glass substrates from aqueous solution containing cadmium acetate, zinc acetate and thiourea at 80±5°C and after annealed at 350°C. The structural, morphological, compositional and optical properties of the deposited Cd1−x Zn x S thin films have been studied by X-ray diffractometer, scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), photoluminescence (PL) and UV–vis spectrophotometer, respectively. X-ray diffraction analysis shows that for x <0.8, the crystal structure of Cd1−x Zn x S thin films was hexagonal structure. For x >0.6, however, the Cd1−x Zn x S films were grown with cubic structure. Annealing the samples at 350°C in air for 45min resulted in increase in intensity as well as a shift towards lower scattering angles. The parameters such as crystallite size, strain, dislocation density and texture coefficient are calculated from X-ray diffraction studies. SEM studies reveal the formation of Cd1−x Zn x S films with uniformly distributed grains over the entire surface of the substrate. The EDX analysis shows the content of atomic percentage. Optical method was used to determine the band gap of the films. The photoluminescence spectra of films have been studied and the results are discussed. [Copyright &y& Elsevier]

The aim of this work is to investigate the undoped LaPO 4 various properties due to the different optimizing temperature and analysing the fluorescence properties. The LaPO 4 nanoparticles has been synthesized using simple Co-precipitation method at different temperature 300 °C, 350 °C, 400 °C, 450 °C, 600 °C and 800 °C. All samples were characterized by structural, morphological and optical studies were investigated. From XRD study of all samples reveals that the annealing temperature increases results from amorphous into the sample became more crystallinity at 800 °C and the monoclinic phase. The presence of functional group observed by FTIR. The morphological study SEM and TEM shows spherical in shape at 800 °C. Atomic percentage of prepared samples were analysed by EDS and found to be value of O (59.8), P (17.69) and La (22.42) at 800 °C. Thermal behaviour of the sample analysed by TG-DTA. The band gap was determined and noticed to be reduced from 3.25 to 2.75 on increasing the annealing temperature. Furthermore, detailed photoluminescence study was performed and discussed. • Cost-effective and facile route is used to prepare LaPO 4 phosphorescent material. • Structural and vibrational analyses approves the phase of LaPO 4 at all annealing temperatures. • EDX study confirm the elemental composition of LaPO 4 and TEM study confirm spherical shape NPs. • The band gap was determined and noticed to be reduced from 3.25 to 2.75 on increasing the annealing temperature. • Furthermore, detailed photoluminescence study was performed and discussed. [ABSTRACT FROM AUTHOR]

The various synthesis methods of LaPO 4 nanoparticles were an active area in many fluorescent applications. Several methods have been introduced for the synthesis of rare earth metals doped LaPO4 nanoparticles. In general, phosphor particles with a relatively large crystallite size with a spherical and agglomerated morphology are favoured for emitting the highest PL intensity. This study is an attempt to present an overview of pure and doped LaPO 4 nanoparticles. • Precipitation method for good results as compared with other methods. • LaPO 4 nanoparticles ensure their stability and suitability for LED applications. • Lanthanum orthophosphate has important properties such as low water solubility, high thermal stability, high index refraction. [ABSTRACT FROM AUTHOR]

Abstract: Polyaniline (PANI) was doped with hydrochloric acid (HCl), succinic acid (C4H6O4) and sulphuric acid (H2SO4) by chemical oxidation method. The samples were characterized by using various techniques such as XRD, photoluminescence IR and UV spectroscopy. FTIR study confirmed the presence of dopant molecules in the molecular structure. UV spectra revealed that absorption peaks at 350nm and 600nm are due to π–π* transition of polyaniline. The strong band at 600nm showed extension of polymer chains in the prepared samples. XRD pattern confirmed the amorphous nature of polymer samples. The photoluminescence (PL) spectrum shows good emission at 490nm. The intensity of photoluminescence depends upon the dopants nature. [Copyright &y& Elsevier]

Zinc oxide (ZnO) thin films deposited on glass substrates at various temperatures 300, 400 and 500 °C by the nebulizer spray pyrolysis technique. X-ray diffraction results indicate that the films are polycrystalline in nature having hexagonal crystal structure with preferred grain growth orientation along (002) plane. The crystallite size increases along (002) plane with temperature increase from 350 to 500 °C and attains a maximum 109 nm at 500 °C. High resolution scanning electron microscopy (HR-SEM) study shows the formation of good quality film on total substrate surface with uniformly distributed tiny spherical shaped grains at 350 °C. The UV–Vis–NIR spectroscopy confirms the possibility of good transparent ZnO thin films deposited with an average transmission of ∼85% in the visible region. Optical band gap energy increases from 3.19 to 3.27 eV with the substrate temperature 350–500 °C. The depression of NBE emission and DL emission of the films were estimated through PL measurements. As the substrate temperature increases, the peak of NBE emission is found to have a blue shift towards lower wavelength side and the same result is also found from the band gap energy determination of optical transmittance measurement. The complex impedance shows two distinguished semicircles and the diameter of the arcs got decreased in diameter as the temperature increases from 350 to 500 °C and thereafter slightly increased. [ABSTRACT FROM AUTHOR]

Highly uniform and well-dispersed ADC (Aluminum doped ceria) films are successfully deposited by NSP technique using cerium nitrate and aluminum nitrate. Effect of Al concentration on the crystallite growth of cerium oxide films is investigated by PL, XRD, FTIR, SEM, AFM UV–vis and I – V studies. Cubic fluorite crystallites are detected by X-ray diffraction pattern with preferred orientation along (1 1 1) direction. Al concentration affects the crysrallinity and structural parameters like grain size, texture coefficient, lattice constant and dislocation density. The change in lattice parameter in doped samples is directly related to the ionic size of the dopants. Because of the smaller size of the dopants, there should be considerable decrease in the lattice parameter of the CeO 2 lattice. The transmittance decreases with increasing Al concentration upto 20% and then decreases due to the presence of covalent bonds between cerium and oxygen or the increase in scattering of photon by crystal defects created by doping or due to the increase in the metal to oxygen ratio and lower ionic size of Al. PL spectra revealed that strong and broad emission band is observed at 425 and 469 nm due to the presence of blue and green shift in the visible region. Large agglomerated ring and hollow spherical crystallites are obtained with the typical size in the range 40–68 nm. I – V characteristics show the rectifying nature of this hetero-junction with a typical forward to reverse current ratio of ~7 in the range −4 to +4 V. The turn-on voltage of the hetero-junction is found to be ~2.1 V. The high values in the ideality factor are caused possibly by various effects such as inhomogeneities of inorganic film thickness, nonuniformity of the interfacial charges and the effect of the series resistance ( R s ). [ABSTRACT FROM AUTHOR]

Pure and Ce doped ZrO 2 nanostructures have been synthesized by the microwave irradiation method. The prepared nanoparticles were characterized by various analytical techniques like Thermogravimetric and Differential Thermal Analysis (TG–DTA), X-Ray Diffraction (XRD), Fourier Transform Infra-Red Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Energy Dispersive Spectrum (EDS) and Transmission Electron Microscopy (TEM). The XRD pattern of Ce doped ZrO 2 nanoparticles have been confirms that the tetragonal structure. TEM observations indicated that the average particle size of the pure ZrO 2 some particles spherical shaped and some particles agglomeration in the range of 16–44 nm. Whereas on addition of Ce agglomeration in the range of 32–56 nm. The pure ZrO 2 and Ce doped ZrO 2 nanoparticles were further characterized for their optical properties by UV–vis reflectance spectra (DRS) and Photoluminescence (PL) spectroscopy. [ABSTRACT FROM AUTHOR]

Cerium oxide thin films are coated on glass substrates by nebulizing spray pyrolysis technique using cerium nitrate and cerium chloride as a source material. Their crystallographic structures, surface morphology, optical properties and I–V characteristics are analyzed as a function of substrate temperature (300–500 °C). XRD is used to estimate the crystallographic texture, crystalline size, strain and lattice constant. All films exhibit a cubic fluorite structure with different preferred orientation depending on the preparation conditions. All the films exhibit dense, smooth and crack-free spherical nanostructures with some uneven surfaces in the range 400 nm. PL analysis indicates the presence of indigo and blue emission in the visible region centered at ∼425 and ∼467 nm respectively. UV-ViS spectra revealed that the films are transparent (70%) in the visible region. Optical parameters like refractive index, optical conductivity and band gap are calculated for different Ts. XPS analysis revealed the existence of Ce, O and C in the films. It demonstrates the prevalent occurrence of Ce 4+ rather than Ce 3+ . I–V characteristics confirm the semiconducting behavior of cerium oxide thin films due to its linear response to applied voltage. [ABSTRACT FROM AUTHOR]

The optoelectronic properties of nebulizer sprayed Cd 1-x Zn x O films at 400 °C with volume ratio of Cd:Zn varying from x = 0 to 1. The prepared films were characterized by structural, morphological, optical, electrical and gas sensing properties. X-ray diffraction (XRD) results suggest that the samples are of a polycrystalline nature and have a mixed hexagonal and cubic crystal structure with orientation growth along (111), (102) plane. Transmittance and the optical bandgap values were found to increase from 2 to 3 eV with increase in concentrations from x = 0 to 1. High resolution scanning electron microscope (HRSEM) studies show changes in surface morphology even after zinc incorporation of the films. The presence of Cd, Zn and O in the deposited films is confirmed by energy dispersive X-ray analysis (EDS). The photoluminescence reveals at room temperature does not exhibit any luminescence related to the detects of the oxygen vacancies for x = 0 and x = 1, as usually shown by CdO and ZnO films. The blue luminescence was shifted to a lower wavelength region and defects was observed from x = 2.5 to 7.5. The complex impedance of the Cd 1-x Zn x O films shows the semicircles and the diameter of the arcs got increased as the concentration increased from x = 0 to1. The maximum ammonia response for Cd 0.25 Zn 0.75 O film was achieved at 50%. • Cd 1-x Zn x O has potential in gas sensor and solar cell applications, such as biological sensing, biological labeling and nano-medicine. • The grain sizes increase with increasing zinc concentration while decreases dislocation density and micro strain. • The surface of Cd 0.75 Zn 0.25 O, Cd 0.5 Zn 0.5 O film belonging to the transition between two structures has mixed together. [ABSTRACT FROM AUTHOR]

Cerium oxide thin films are deposited on glass substrates with different surfactants by nebulized spray pyrolysis technique. Their crystallographic structures, surface morphology, optical properties and I-V characteristics are analyzed as a function of surfactants. All films exhibit cubic fluorite structure with preferred orientations along (1 1 1) and (2 0 0) direction depending upon preparation conditions with an average grain size 37 nm. Fourier Transform-Infra Red analysis confirmed the presence of terminal stretching (Ce=O) and phonon band (Ce-O) of the metal oxide network. The intensity of carbonation bands is diminished with the addition of amine groups. The films exhibit dense, smooth and crack-free tiny particles composed of closed chains, golf-ball, hollow spherical and slap shaped nanostructures with an average size 180 nm. It also exhibits nicely separated well-outlined cones and spheres with rounded apex having an average roughness 121 nm. Optical spectra reveal that the films are transparent (70%) in the visible region. Optical parameters like refractive index, optical conductivity and band gap are calculated for different surfactants. Photo Luminescence analysis indicates the presence of blue and green emission peaks in the visible region centered around ~425 and ~467 nm attributed to the persistence of electron-phonon interaction between Ce4f and O2p bands. X-ray Photoelectron Spectroscopy analysis reveals the existence of Ce, O, Na and C atoms in the prepared films. It also brings out the dominant occurrence of Ce4+ rather than Ce3+ in the films. It is ensured that the rare earth compounds having unpaired electrons can give raise an extra satellite peak (923.5 eV) due to photoelectron energy gain or loss assigned to finger print of CeO2 phase. The electrical conductivities are in the range 7.20×10-7 to 1.21×10-4 S/cm for different surfactants. [ABSTRACT FROM AUTHOR]

Abstract: Cerium oxide (CeO2) nanoparticles with good crystallinity and smooth surface are prepared by chemical precipitation method with different bases (NH3, NaOH and KOH) using cerium nitrate as a source material. The effect of precipitating agents on the growth of cerium oxide nanoparticles are investigated by Photoluminescence (PL), X-ray diffraction (XRD), Fourier transform-infra red spectroscopy (FTIR), thermo gravimetric–differential thermal analysis (TG-DTA), Scanning electron microscope (SEM), Transmission electron microscope (TEM), and X-ray Photoelectron Spectroscopy (XPS). Cubic fluorite crystallites are detected by XRD pattern with preferred orientation along (111) direction. PL spectra revealed the presence of a strong and broad emission band at425nm due to the blue shift in the visible region. The broad band below 700cm−1 is due to the envelope of the phonon band of metal oxide (Ce–O) network as revealed by the IR spectra. The TG-DTA curves revealed that the total weight loss of the samples is 19.67% when the samples are heated upto 800°C. SEM images exhibits weakly agglomerated spheroid crystallites are obtained with the typical size in the range 10–50nm. TEM images display that the particles are nearly spherical and square in shape with diameter 8–12nm. XPS spectrum confirms the existence of Ce4+ oxidation states in CeO2samples. [Copyright &y& Elsevier]

Cerium oxide thin films are coated on glass substrates by nebulizer spray pyrolysis technique using cerium nitrate as a source material. Their crystallographic structures, surface morphology, optical properties and I–V characteristics are studied as a function of substrate temperature (300–500°C). XRD is used to estimate the crystallographic texture, grain size, strain and lattice constants. All the films exhibit a cubic fluorite structure with different preferred orientations depending on the preparation conditions. Optical analysis reveals that the films are transparent (70%) in the visible region. The optical bandgap (E g) is calculated in the range 3.28–3.52eV. The optical parameters like absorption coefficient, extinction coefficient, packing density and refractive index are calculated for different substrate temperatures. SEM images exhibit golf-ball like morphology with small cracks and pores. The maximum conductivity obtained is 2.90×10−6 S/cm at 400°C. [ABSTRACT FROM AUTHOR]

Abstract: Ni-doped zinc oxide (Ni:ZnO) thin films were deposited on glass substrates by sol–gel dip-coating technique with different pH values. The films were characterized structural, morphological, compositional and optical properties respectively. X-ray diffraction revels that all samples have a polycrystalline in nature with hexagonal wurtzite structure. The structural parameters such as crystallite size, dislocation density and micro strain were calculated from XRD studies. Scanning electron microscopy shows irregular grains with average grains size found to be ∼150nm at 400°C. Energy dispersive X-ray analysis indicates that the presence of Ni, Zn and O elements with average atomic percentage of Ni:ZnO was 04.19:44.99:50.82 at 400°C. Optical absorption spectra show that the band gap energy is decreases with the increase in pH values. [Copyright &y& Elsevier]

Abstract: Highly uniform and well-dispersed cerium oxide nanoparticles are successfully synthesized by simple precipitation method using cerium nitrate and ammonia. Effect of annealing temperature on the crystallite growth of cerium oxide nanoparticles is investigated by PL, XRD, FTIR, SEM, TEM, XPS, TG–DTA and I–V studies. Cubic fluorite crystallites are detected by X-ray diffraction pattern with preferred orientation along (111) direction. Annealing temperature affects the crysrallinity and structural parameters like grain size, texture coefficient, and dislocation density. The activation energy of cerium oxide (CeO2) nanoparticles during annealing is found to be 1.004eV. PL spectra revealed that strong and broad emission band is observed at 425nm due to the presence of blue shift in the visible region. Large agglomerated spheroid crystallites are obtained with the typical size in the range 4–12nm. XPS spectrum confirms the existence of Ce4+ oxidation states in Cerium oxide nanoparticles. The activation energy is calculated as 0.984eV. [Copyright &y& Elsevier]

Abstract: Synthesis of polypyrrole and polypyrrole/TiO2 composites samples using chemical oxidative method at room temperature with various dopant percentages of TiO2. The samples were characterized by UV–vis spectrometer, Fourier transmittance infra red (FTIR) spectrometer, X-ray diffraction (XRD), Scanning electron microscopy (SEM) and non linear optics (NLO) studies. Optical spectra reveal the absorbance band at 250nm represents the characteristic peak of TiO2 particles. The second band is shifted at 300nm with π–π* transition. FTIR confirms the presence of TiO2 in the molecular structure. The intensity of peaks found to be decreased with the increase of TiO2 content. A small band at 1699cm−1 and 1107cm−1 corresponds to Ti–O–C stretching mode in each case. This band indicates the formation of polypyrrole/TiO2 composites. XRD patterns reveal the samples were polycrystalline nature with tetragonal structure and (101) plane as preferential orientation. SEM studies reveal the formation of uniform granular morphology with average grain size of ∼0.4μm for (50%) TiO2 sample. NLO studies reveal that the polypyrrole and polypyrrole/TiO2 composites possess non-linear optical properties. [Copyright &y& Elsevier]

Highly uniform and well-dispersed ring shaped particles of CDC (Cobalt doped cerium oxide) films are successfully deposited by Nebulizer Spray Pyrolysis (NSP) technique. The structural, morphological, optical and photo-diode properties of the films are investigated. Cubic fluorite crystallites are detected by X-ray diffraction pattern with preferred orientation along (111) direction. Co concentrations distress the crystallinity and structural parameters. The transmittance decreases with increasing Co concentration due to the presence of covalent bonds between cerium and oxygen. PL spectra revealed that three consistent sharp and broad peaks observed at 369 (3.31 eV), 394 (3.14 eV) and 425 nm (2.91 eV) correspond to near-band-edge emission (NBE) in UV region, deep level emission (DLE) in violet and blue of the visible region respectively. The deep level emissions result from the recombination of electrons with holes trapped in singly ionized oxygen vacancies (Vo+). Large agglomerated ring, button and spherical crystallites are obtained with the typical size in the range 83–207 nm. XPS analysis exhibits the presence of Ce, Co, O, C and Na in the films that indicates the non-stoichiometric behavior. I-V characteristics show the rectifying nature with a typical forward to reverse current ratio of ~7 in the range −4 to +4 V. The turn-on voltage of the hetero-junction is found to be ~1.7 V. The transient photocurrent behavior indicates that the device has a good stability and quick response to suggests that the prepared heterojunction device can be used as a white light photodetector and UV detector applications. [ABSTRACT FROM AUTHOR]

A simple, less time consuming, cost ineffective sol–gel method was used to synthesis TiO 2 nanoparticles (TiO 2 ) and TiO 2 –SiO 2 nanocomposites (TiO 2 –SiO 2 ) using titanium tetra isopropoxide as TiO 2 and silicic acid as SiO 2 precursors respectively. The synthesized nanocomposites were characterized by XRD, SEM, TEM, UV–visible, FTIR and BET analysis. The quantum confinement effect of TiO 2 and TiO 2 –SiO 2 was confirmed by a blueshift observed in UV–visible spectra. The band observed at 950 cm −1 in FTIR analysis confirmed the presence of Ti–O–Si bonds, the TEM analysis shows both the TiO 2 and TiO 2 –SiO 2 were in nanometer size. The BET (Brunauer– Emmett–Teller) specific surface areas of the samples were 65 and 75 m 2 /g for TiO 2 and TiO 2 –SiO 2 respectively. The power conversion efficiency (PCE) of the nanocomposites were studied by using Keithely electrometer and multimeter and it was found to be 2% and 2.5% for eosin-Y sensitized TiO 2 and TiO 2 –SiO 2 nanocomposites respectively. [ABSTRACT FROM AUTHOR]

Abstract: Polyaniline (PANI)/TiO2 nanocomposite samples with various dopant percentages of TiO2 were synthesized at room temperature using a chemical oxidative method. The samples were characterized by ultraviolet-visible spectrometer, Fourier transform infrared (FTIR) spectrometer, X-ray diffraction (XRD), scanning electron microscopy (SEM), EDAX and conductivity measurements. Incorporation of TiO2 nanoparticles caused a slight red shift at 310nm in the absorption spectra due to the interactions between the conjugated polymer chains and TiO2 nanoparticles with π–π⁎ transition. FTIR confirmed the presence of TiO2 in the molecular structure. In PANI/TiO2 composites, two additional bands at 1623cm−1 and 1105cm−1 assigned to Ti–O and Ti–O–C stretching modes were present. It can be concluded that Ti organic compounds are formed with an alignment structure of TiO2 particles. XRD patterns revealed that, as the TiO2 percentage was increased, the amorphous nature disappeared and the composites became more strongly oriented along the (110) direction, which showed the tetragonal structure of nanocrystalline TiO2. SEM studies revealed the formation of uniform granular morphology with average grain size of 200nm for (50%) PANI/TiO2 nanocomposite samples. [Copyright &y& Elsevier]

Abstract: Cadmium chromium sulphide (CdCr2S4) thin films have prepared on indium doped tin oxide coated conducting glass (ITO) substrates from an aqueous electrolytic bath consists of CdSO4, Cr2O3 and Na2S2O3 using potentiostatic electrodeposition technique. The deposited films are characterized using X-ray diffraction, scanning electron microscopy, energy dispersive analysis by X-rays and optical absorption techniques, respectively. X-ray diffraction pattern reveals that the deposited films possess polycrystalline nature with cubic structure. Surface morphology and film composition shows that the films with smooth surface and better stoichiometry are obtained under optimized deposition condition. The optical parameters such as band gap, refractive index and extinction coefficient are calculated from optical absorption measurements. The experimental observations are discussed in detail. [Copyright &y& Elsevier]