Comparative study of TiO₂ nanoparticles applied to dye-sensitized solar cells

Laboratoire de Photovoltaïque, Centre de Recherches et des Technologies de l’Energie, BP 95, Hammam-Lif 2050, Tunisia

^a e-mail: besma.yacoubi@gmail.com

Received: 9 August 2012
Revised: 15 July 2013
Accepted: 3 December 2013
Published online: 3 February 2014

Abstract

Microcrystalline titanium oxide (TiO₂) particles of anatase crystal phase were prepared by the sol-gel route, varying thermal treatment conditions (400 °C and 600 °C), for a comparison purpose with commercial TiO₂ (P25). Structural, optical and electrical properties were investigated for dye-sensitized solar cells (DSSCs) application. Both microcrystalline TiO₂ particles, synthesized by the sol-gel method and obtained from the P25 powder were used to prepare a light scattering layer of the working electrode. The obtained electrodes were then immersed in a solution of N-719 (ruthenium) dye, at the ambient temperature, during 24 h. Finally, the DSSCs were assembled, the short circuit photocurrent, the open circuit photovoltage, and the power conversion efficiency were measured using an I-V measurement system. The overall conversion efficiencies for all elaborated DSSCs were proximate. A maximum efficiency of 2.3% was achieved for the sol-gel TiO₂ thin film annealed at 400 °C, under one sun irradiation, with an open circuit voltage of 0.61 V and a current density of 6.54 mA/cm². The higher efficiency value of the sol-gel TiO₂ sample, annealed at 400 °C, was attributed to the uniformity of the prepared titanium oxide substrate, which provides a better surface for the dye absorption.