Tuning TiO2 Porosity of Multilayered Photoanode Towards Enhanced Performance of Dye Sensitized Solar Cell

Abstract

In this paper, we prepared Titanium Dioxide (TiO2) based dye sensitized solar cells (DSSC). Downscaling of commercial TiO2 powder have been achieved by systematic ball milling carried out using home-made ball milling device. Thin films were prepared and samples were characterized by XRD, SEM, UV-Vis and I-V. The main objective of this work is to prepare TiO2 based (DSSC) using N3 dye and study the effect of the TiO2 grain size inside the photoanode layer on the efficiency of the solar cell. UV-vis study of nanometer sized TiO2 particles showed that the energy gab has shifted towards the lower wavelength in electromagnetic spectrum (blue shift), and then optical band gap is an indirect and allowed transition. Energy gap calculations of related grain size of showed quantum confinement effect. A sophisticated strategy for TiO2 films consisting of tailoring monolayer, bilayer and trilayer of mixed multisized nanoparticles were adopted and investigated as DSSC electrodes. Our results showed that the dye sensitized solar cells can be substantially altered due to the designs and the particle size distributions of the TiO2 photoelectrode. The maximum efficiency of 0.5% was reached by TiO2 photoelectrode designed as a trilayer with a particles of wide size distribution from about 12 to 340 nm in the middle layer. The approach of light scattering in submicrometer‐sized TiO2 nanoparticles aggregates was adopted in order to interpret the enhancement of our DSSC efficiency over extending the length transported by electromagnetic wave hence to promote the light acquiring efficiency of photoelectrode thin film. The relatively larger particle sizes afford the TiO2 films with both better packing and an increased capability for scattering of the incident electromagnetic wave, and hence improves our DSSC efficiency.