Highly efficient dye sensitized solar cells based on ordered and disordered mesoporous titania thick templated films

Abstract

Ordered and disordered mesoporous titania thick films up to about 7 μm thickness were successfully synthesized by an evaporation-induced self-assembly (EISA) process using dip and spin coating methods. To obtain crack-free thick films with high crystallinity and roughness factor we used a stabilization step after each coating and a calcination step after every five layers. Transmission electron microscopy (TEM), X-ray diffraction (XRD), scanning electron microscopy (SEM), BET analysis, ellipsometric analysis and UV-visible absorption spectroscopy (UV-vis) were used to characterize the microstructural features of the films. These mesoporous TiO₂ thick films were tested in dye-sensitized solar cells (DSSCs). The photovoltaic performances of cells made from meso-films prepared by dip and spin coating methods were compared and a maximum efficiency of 8.33% was achieved. This is the highest efficiency so far reported for DSSCs made from mesoporous titania templated films. The mesostructured films were compared with nanocrystalline TiO₂ films (NC-TiO₂) that are commonly used in DSSCs and showed superior performance.