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Gamma irradiation is recognized to modify the properties of thin films. In the present work, the effects of gamma irradiation on the nano-structural electrical and optical properties as of function of radiation dose has been studied. The PdS thin films deposited on glass substrate by successive ion layer adsorption and reaction (SILAR). The deposited thin films were irradiated by the gamma radiation with the 60Co for the Gamma dose range from 0 to 100 kGy. As deposited and gamma irradiated PdS thin films were investigated by impedance spectroscopy, X-ray diffraction, energy dispersive X-ray, scanning electron microscopy and Photoluminescence. The X-ray diffraction patterns exhibited a tetragonal structure of PdS thin films before after gamma irradiation, and demonstrated the changes in crystallinity, dislocation density, crystallite size and micro-strain. Field emission scanning electron microscopy and energy dispersive X-ray study conformed atomic composition of PdS thin film (1:1 ratio of Pd:S) and revealed that shape and size of grain depend on dose of gamma irradiation. Photoluminescence peak are found to be shifted to longer wavelength, intensity and width of photoluminescence peak increased for the gamma irradiated samples with increasing gamma dose. Impedance spectroscopy revealed that the enhancement of charge carrier density of irradiated PdS thin films increased linearly with gamma dose. The achieved results prove that gamma irradiation has superficial influence on nano-structural, optical and electrical properties of the deposited PdS thin films. [ABSTRACT FROM AUTHOR]

The electrical and photoresponse properties of Au/nanostructure AZO/p-Si/Al diode were investigated. Al-doped ZnO (AZO) thin films were deposited via pulsed laser deposition method on silicon substrate. Structural properties of the films were performed by using transmission electron microscopy and X-ray powder diffraction (XRD). The XRD patterns showed that the AZO films are polycrystalline with hexagonal wurtzite structure preferentially oriented in (002) direction. Electrical and photoresponse properties of the diode were analyzed under in a wide range of frequencies and illumination intensities. It is observed that the reverse current of the diode increases with increasing illumination intensity. This result confirms that the diode exhibits both photoconducting and photovoltaic behavior. Also, the transient photocurrent, photocapacitance and photoconductance measured as a function of time highly depend on transient illumination. In addition, the frequency dependence of capacitance and conductance is attributed to the presence of interface states. [ABSTRACT FROM AUTHOR]

It is shown that the nanostructures of vanadium pentoxide (VO) obtained by laser treatment of films grown by thermal evaporation differ significantly in their properties from analogues based on VO. Results of XRD and SEM studies show the increase in grain size with the increasing intensity of the laser radiation, and spectral analysis data indicate a decrease in the band gap. [ABSTRACT FROM AUTHOR]

We have investigated the influence of Ag doping on zinc oxide thin films. Pure and Ag doped, preferentially oriented transparent zinc oxide thin films were prepared by sol gel technique on a glass substrate using diethyl amine as a stabilizer. The X-ray diffraction analysis revealed that the films with hexagonal wurtzite type structure were polycrystalline in nature with a preferred grain orientation in the 101 direction. The crystallite sizes decreased from 34 nm to 27 nm after silver doping. Both photoluminescence and optical transmission measurements showed that the band gap increased after the Ag doping. The structure and optical characterization studies clearly indicated the incorporation of Ag in ZnO. Hence, the observed increase in the optical band gap and decrease in crystallite size can be directly attributed to the effect of Ag ion incorporation into the ZnO lattice. [ABSTRACT FROM AUTHOR]

Magnesium zinc tin oxide (MZTO) quaternary systems were prepared using solution-processed method. Assessment of the Mg dopant content of the MZTO quaternary system was done to obtain a better performance of the films in the device applications. The combination of silicon and MZTO system exhibited rectifying behavior. It has been observed that the current in the reverse direction is increased by illumination of 30 mW/cm. The capacitance-time characteristics were measured by transient photocapacitance spectroscopy. The composition of MZTO was studied by absorbance, transmittance and reflectance measurements. It has been seen that the band gap (~4.07 eV) of MZTO films remains almost constant with regard to the increasing Mg dopant content while the thin film of ZTO ternary system without Mg has band gap of 3.9 eV. [ABSTRACT FROM AUTHOR]

TiO thin film has been widely used as photoelectrode in dye-sensitized solar cells. It can also be used in quantum dot synthesized solar cells. Study of its effects in different spectrum of light is important for its use in solar cells. We have reported effects of 1064 nm laser on the surface morphology, structural and optical properties of nanostructured TiO thin film deposited on glass substrates using sol-gel spin coating technique. Q-Switched Nd:YAG pulsed laser at various power densities is used in this study. Surface morphology of the film is investigated using X-ray diffraction (XRD) and atomic force microscopy technique. The XRD pattern of as deposited TiO thin film is amorphous and after laser exposure it became TiO anatase structure. Atomic force microscopy of the crystalline TiO thin film shows that the grain size increases by increasing laser power density. The calculations of the band gap are carried out from UV/Visible spectroscopy measurements with JASCO spectrometer. For laser power density of 25 MW/cm there is an increase in the transmission and it decreases at the value of 38 MW/cm and band gap decreases with increasing laser power density. Photoluminescence spectra of the crystalline TiO thin film indicate two broad peaks in the range of 415 and 463 nm, one for band gap peak (415 nm) and other for oxygen defect during film deposition process. [ABSTRACT FROM AUTHOR]

The effects of laser irradiation on the surface, structure and optical properties of SnO thin films deposited on glass substrates using electron beam evaporation, are investigated. The thin film samples are irradiated using fundamental beam at 1064 nm from Q-switched Nd:YAG pulsed laser with different power densities. Structural morphology of the film is investigated using XRD patterns and AFM image. Both XRD pattern and AFM image show increase in grain size of the film with increasing laser power density. Other optical phenomena, photoluminescence emission, transmission, refractive index determination and optical band gaps calculations are also carried out at various laser power densities. Results from all these investigations reveal expansion in grain size of the crystalline SnO thin film with increasing laser power density. [ABSTRACT FROM AUTHOR]

The effect of TiO2 nanoparticles on the photophysical properties of ternary conjugated polymer (CP) blends of poly(9,9-dioctylfluorene-2,7-diyl) (PFO), poly 9,9-dioctylfluorene-alt-benzothiadiazole (F8BT) and poly(2-methoxy-5(2-ethylhexyl)-1,4 -phenylenevinylene (MEH-PPV) thin films was investigated. This ternary blend used a fixed amount of PFO as the donor with MEH-PPV and F8BT in various ratios as the acceptors. The solution-blending method and the spin-coating technique were used to prepare the blends and the thin films, respectively. Through efficient Förster Resonance Energy Transfer (FRET), the desired white emission was achieved with PFO/0.3 wt.% F8BT/0.5 wt.% MEH-PPV ternary blend thin film. Additions of nanoparticles up to 10 wt.% dramatically intensified the white emission which then dimmed at higher contents due to agglomerations. The current density–voltage characteristics of the nanocomposite thin films exhibited dependency on the content and distributions of the nanoparticles. Finally, a possible underlying mechanism for the intensification of emission is proposed. [ABSTRACT FROM AUTHOR]

We developed a composite consisting of mesoporous ZrO 2 thin films supporting catalytically active gold nanoparticles (Au NPs) for the oxidative removal of carbon monoxide (CO). At first, highly ordered mesoporous ZrO 2 (m-ZrO 2) thin films are prepared by sol-gel-based spin-coating process followed by a controlled thermal treatment process in air. Then, Au NPs are successfully dispersed and deposited over the entire framework of mesoporous ZrO 2 thin films to form Au/m-ZrO 2 films. The specific surface area and crystallinity of the m-ZrO 2 thin films as well as the periodicity of the mesoporous framework can be controlled by adjusting the calcination temperature and the synthetic parameters. The catalytic efficiency of the optimized Au/m-ZrO 2 composite film toward CO conversion reaches 94% of circulation time, and is well-retained even after 1 h (∼88%). Image 1 • Oxidative removal of carbon monoxide (CO) at room temperature is introduced. • Ordered mesoporous ZrO 2 thin films are prepared by a sol-gel method. • Au nanoparticles (NPs) are dispersed over the entire framework of mesoporous ZrO 2. • The catalytic efficiency of the mesoporous ZrO 2 film with Au NPs reaches 94.0%. • Indoor air purification devices can be fabricated using our catalysts. [ABSTRACT FROM AUTHOR]