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Zinc Oxide (ZnO) nanoparticles exhibit a wide range of applications owing to their unique properties such as low cost, non-toxicity, abundance in nature and suitability for doping. In the present study, ZnO and Aluminium doped Zinc Oxide (Al-ZnO) nanoparticle thin films were prepared on FTO glass substrate by sol-gel and spin coating methods. The structural and morphological characteristics of the undoped and Al-doped ZnO nanoparticles were examined by X-ray Diffraction (XRD) and High Scanning Electron Microscope (HR-SEM) analysis, respectively. The XRD studies revealed the hexagonal wurtzite structure of the as-synthesized ZnO samples and the crystallite size was estimated using Scherrer’s formula to be 28 and 30 nm respectively, in the case of the undoped and doped ZnO nanoparticles. The average particle sizes in nanoscale were analysed using FESEM and found to be 38 nm and 42 nm for the bare and doped samples. The surface area of the as-synthesised particles were correspondingly estimated as 46 m2/g and 25 m2/g and their relative pore volume and diameter were determined using BET analysis. The field dependent photoconductivity of Al-ZnO shows a significant increase as against the bare ZnO.

We present a detailed examination on the microstructural, structural, optical and electrical properties of one dimensional (1D) and three dimensional (3D) titania nanostructures in comparison with zero dimensional (0D) titania nanoparticles. Material characterization by X-ray Diffraction technique confirms the formation of anatase phased TiO2 nanoparticles and rutile phased nanorods and nanoflowers. Morphological investigations were done with Field Emission Scanning Electron Microscopy and High Resolution Transmission Electron Microscopy. Optical properties of the samples were studied using UV-Visible Diffuse Reflectance Spectroscopy and their optical band gap energies were calculated using Kubelka-Monk method. Although the 1D nanorods possess faster electron transport than the nanoparticle structure, their low surface area has detained that morphology to absorb more incident radiation. However, the 3D nanoflower morphology coupled with excellent light scattering capability and enhanced optical absorption resulted in a 7 fold increase in dark and 26 fold increase in photocurrents compared to nanorod and nanoparticles. Dye Sensitized Solar Cells (DSSCs) are developed using Safranine O dye and their I-V characteristics were examined. Improved performance of DSSC is observed in the case 3D nanoflower structures delivering efficiency of about 3.56 %. The findings of this work essentially suggest that the optical transport properties of the photoanode materials and therefore cell performances are significantly influenced by their respective morphologies.