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Nanostructure and electrical properties of iridium oxide () thin films prepared by spray pyrolysis technique (SPT) have been experimentally characterized. The effect of solution molarity (SM) and substrate temperature () on the nanostructure features and electrical conductivity of these films has been investigated. The results of X-ray diffraction (XRD) showed that all samples prepared at with different SM, appear almost in amorphous form. XRD revealed that the films deposited at were tetragonal structures with a preferential orientation along direction. Moreover, the degree of crystallinity was improved by solution molarity. Single order Voigt profile method has been used to determine the nanostructure parameters at different SM and . The dark conductivity measurements at room temperature as a function of SM were observed and the value of conductivity were slightly increases at higher SM, reaching the bulk value of 20 . The values of activation energy of and of were found to be 0.21 eV and ·, respectively.

Thin films of Ru doped TiO 2 have been deposited on glass substrates at different doping concentration (0.05, 0.07, 0.09, 0.11 mol l −1 ) by the sol gel method. The prepared thin films were studied: their structural, morphological, optical and photocatlytic properties. The XRD spectra confirm that all the samples have anatase phase with preferential orientation along (101) plane. The position of (101) peaks shift to higher angles with increase doping concentration and 0.07 mol l −1 sample have a sharp and high intensity diffraction peak. Due to condensation and agglomeration effect. The thickness of the thin films increases from 110 nm to 255 nm with the increment of Ru concentrations. AFM images show that the films had good quality and pyramidal shape was distributed over their entire surface. Transmittance and absorbance spectra of the un-doped and Ru doped TiO 2 thin films were recorded by UV-vis spectrometer. The optical band gap of the thin films increases from 3.66 eV to 3.85 eV as the Ru amount increases; this is due to the Moss-Burstein effect. Calculated results show that both the excitation coefficient (k) and refractive index (n) decreases with wavelength at all Ru concentration. Optical conductivity can improve after doping which can be a suitable material for use in sensor and solar cell applications. The photocatalytic activity was investigated by monitoring the degradation of methylene blue (MB) under visible and sun light. The results revealed that the photocatalytic activity under sun light was higher comparing to UV light for all films. Ru doped TiO 2 thin films enhance the efficiency of its photocatalytic activity. It was found that the percentage of degradation was higher in 0.11 mol l −1 Ru doped TiO 2 when compared with other films.