Dye-sensitized solar cell using sprayed ZnO nanocrystalline thin films on ITO as photoanode

•ZnO thin films are successfully deposited onto ITO glass substrate with preferential orientation along (0 0 2) plane.•Films with better crystallinity and maximum transmittance are obtained for the as deposited film (annealing is not required).•The absorption of dye in mesoporous ZnO films was confirmed by UV–Vis spectra.•The obtained band gap value of 3.2 eV expected to facilitate electron injection from photo-exited dye molecules in DSSC.

ZnO thin films had been successfully prepared by spray pyrolysis (SP) technique on ITO/Glass substrates at different substrate temperature in the range 250–400 °C using Zinc acetylacetonate as precursor. The X-ray diffraction studies confirmed the hexagonal wurtzite structure with preferred orientation along (0 0 2) plane at substrate temperature 350 °C and the crystallite size was found to vary from 18 to 47 nm. The morphology of the films revealed the porous nature with the roughness value of 8–13 nm. The transmittance value was found to vary from 60% to 85% in the visible region depending upon the substrate temperature and the band gap value for the film deposited at 350 °C was 3.2 eV. The obtained results revealed that the structures and properties of the films were greatly affected by substrate temperature. The near band edge emission observed at 398 nm in PL spectra showed better crystallinity. The measured electrical resistivity for ZnO film was ∼3.5 × 10−4 Ω cm at the optimized temperature 350 °C and was of n-type semiconductor. The obtained porous nature with increased surface roughness of the film and good light absorbing nature of the dye paved way for implementation of quality ZnO in DSSCs fabrication. DSSC were assembled using the prepared ZnO film on ITO coated glass substrate as photoanode and its photocurrent – voltage performance was investigated.

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