Synthesis and characterization of nanostructured catalysts for photovoltaic applications

Abstract

The objective of this project was to investigate the effect of the morphology of titanium dioxide (TiO2) nanoparticles on the electron transport properties and light harvesting potential in a dye sensitized solar cell (DSSC). Particular attention was given to develop synthetic methods to produce metal oxide photocatalysts with similar crystallite size, with different morphologies (spheres, fibers, hierarchical spheres, and globular structures) with the aim of studying the relationship between morphology and photocatalytic activity. The addition of CNTs to the synthesis showed that they acted as nucleation sites and altered the morphology. Materials were fully characterized using Raman, SEM, XRD, BET, and FTIR. The photocatalytic activity of the as-synthesized materials was tested in a DSSC configuration and characterized using electrochemical impedance spectroscopy. It was found that the different morphologies had different light scattering properties which influenced the efficiencies. Based on these preliminary results, the nanofibres prepared in heptane performed the best, with good dye loading, electron lifetime and diffusion coefficient. The addition of a scattering layer using hierarchical spheres showed promising results in decreased transparency and increased efficiency. The addition of CNTs had an adverse effect, this could be due to light blocking by the black CNTs and increased recombination with the electrolyte.