Synthesis and Characterization of WO3 Doped TiO2 Particle/Nanowire Layer in Dye-Sensitized Solar Cells

Abstract

Dye-sensitized solar cells (DSSCs) have been intensively studied since their discovery; however, a number of problems remain to be solved in order to enhance their efficiency. In particular, one of the main limiting factors is the electron recombination that occurs due to contact between the transparent conductive oxide and the redox electrolyte. In this work, we report an improvement in the photovoltaic characteristics of dye-sensitized solar cells by using mixtures of TiO2, TiO2 nanowires (TNWs), and WO3. DSSCs were constructed by application of WO3 mixed with a composite of varying percentages of TiO2 nanoparticle and TNWs. The addition of WO3 reduces the surface trap states of TiO2, improving its power conversion efficiency by suppressing charge recombination, and increasing the driving force of electron injection. A DSSC fabricated using a TiO2-WO3 mixture was found to have a maximum conversion efficiency of 5.47% owing to the effective prevention of electron recombination. As a result, DSSCs based on TiO2-WO3 mixtures exhibited better photovoltaic performance compared to cells fabricated from pure TiO2