CZTS counter electrode in dye-sensitized solar cell: enhancement in photo conversion efficiency with morphology of TiO2 nanostructured thin films

In the present investigation, kesterite phase Cu2ZnSnS4 (CZTS) nanoparticle, and one-dimensional (1D) nanorods and three-dimensional (3D) flower-like rutile phase TiO2 thin films were obtained by the conventional hydrothermal method. The (112) plane–oriented single-phase CZTS nanoparticles with chemical composition Cu/(Zn + Sn) = 0.84, 0.90, 1.05 were obtained by changing the copper concentration of the precursor solution. The CZTS thin films were prepared on fluorine-doped tin oxide (FTO) substrate by the doctor blade coating method. The effect of reaction time on growth of the hydrothermal deposited rutile phase TiO2 nanorod thin films were investigated. The detailed structural properties, phase identification, and morphological developments were investigated using X-ray diffraction (XRD), Raman spectroscopy, high-resolution transmission electron microscopy (HRTEM), and scanning electron microscopy (SEM) techniques. The dye-sensitized solar cells were fabricated with CZTS counter electrodes (CEs) and hydrothermal deposited nanostructured TiO2 photoanodes. The device formed with three-dimensional TiO2 nanostructured photoanode showed higher efficiency (2.65%) than one-dimensional microstructures (1.74%). The study demonstrates that the nanostructure-based morphologies of TiO2 photoanodes affect the performance of CZTS CEs–based dye-sensitized solar cell.