Effect of Ni dopant in TiO₂ matrix on its interfacial charge transportation and efficiency of DSSCs

Employing the prepared pure TiO₂ and Ni doped TiO₂ as photoanode material, dye sensitized solar cells (DSSCs) are fabricated with ruthenium complex as dye-sensitizer [Cis-bis(isothiocyanato) bis(2, 2′-bipyridyl-4, 4′-dicarboxylato)ruthenium(II) also called as N3 dye] and LiI as redox electrolyte. In this concern, pure TiO₂ and Ni–TiO₂ are prepared through sol–gel technique. The structural, optical and electrical properties of the prepared materials are investigated using XRD, UV–Vis and impedance analyses respectively. The XRD pattern reveals pure crystalline anatase phase of pure TiO₂ and Ni–TiO₂ and the crystallite size was found to be in the range of 7–11 nm. UV–Vis spectroscopy shows the enhancement of absorption spectrum in UV region with red shift was observed by Ni doping. The electron transport properties of the prepared TiO₂ and Ni doped TiO₂ shows higher conductivity in 3% Ni doped TiO₂ confirmed from impedance studies. The interfacial charge transport resistances and chemical capacitances of the fabricated DSSCs are evaluated from the EIS investigations and the photovoltaic performance of Ni doped TiO₂ based DSSC shows enhanced efficiency up to 4%.