Laser induced photocurrent and photovoltage transient measurements of dye-sensitized solar cells based on TiO2 nanosheets and TiO2 nanoparticles

Dye-sensitized solar cells (DSSCs) based on TiO2 nanoparticles and TiO2 nanosheets with exposed {001} facets are investigated using laser-induced photovoltage and photocurrent transient decay (LIPVCD) measurements. We adopted a simplified version of LIPVCD technique, in which a single illumination light source and a laboratory oscilloscope could be conveniently used for the measurements. Although the {001} surface of TiO2 nanosheets allowed a noticeably slower recombination with the electrolyte, this was counterpoised by a slower electron transport probably due to its planar morphology, resulting in a shorter diffusion length in TiO2 nanosheets. The nanosheet morphology also resulted in less surface area and therefore reduced short circuit current density in the fabricated devices. Ourwork highlights the fact that the morphological parameters of TiO2 nanosheets finally resulting after electrode film deposition is of no less importance than the reported efficient dye adsorption and slow electron recombination at the surface of individual nanosheets. (C) 2016 Elsevier Ltd. All rights reserved.