Morphological control of TiO2 nanocrystals by solvothermal synthesis for dye-sensitized solar cell applications

Abstract TiO2 nanocrystals TETA1, TPRA2, TIPA3, TBUA4, TTBA5, and TBNA6 were prepared using ethanol, 1-propanol, isopropyl alcohol, n-butanol, tert-butyl alcohol, and benzyl alcohol, through the alcohol-based solvothermal method. The morphology, size, and crystallinity of the TiO2 nanocrystals were characterized utilizing transmission electron microscopy, scanning electron microscopy, X-ray diffraction, and high-resolution transmission electron microscopy analyses. These six TiO2 nanocrystals with different morphologies were used as photoanodes in dye-sensitized solar cells (DSSCs) and their cell efficiencies were 8.08 % (TETA1), 8.38 % (TPRA2), 9.18 % (TIPA3), 7.68 % (TBUA4), 7.85 % (TTBA5), and 6.10 % (TBNA6). Among them, the well dispersed rod-shaped one-dimensional TiO2 (TIPA3) photoanode based cell showed the best power conversion efficiency due to its highest dye loading and excellent light-harvesting capacity. This TIPA3 cell demonstrated a fast electron transport rate with suppressed charge recombination which was confirmed from electrochemical impedance spectroscopy.