Plasmonic enhancement of the performance of dye-sensitized solar cells by incorporating TiO2 nanotubes decorated with Au nanoparticles

The TiO2 nanotubes (TNT) are synthesized and decorated with Au nanoparticles, forming a TNT-Au composite. This TNT-Au composite is incorporated into a TiO2 nanocrystalline film to form a multifunctional composite photoanode and the dye-sensitized solar cell (DSSC). The influences of different amounts of TNT-Au on the performance of the multifunctional composite photoanodes and DSSCs are investigated. Studies indicate that, the introduction of TNT-Au improves remarkably the transport rate of electrons, enhances the ability of photoanode to scatter and capture incident light, reduces the charge transfer resistance, and thereby improves significantly the short-circuit current density (Jsc) and photoelectric conversion efficiency (PCE) of the DSSCs. The maximal Jsc of 14.72 mA cm−2 and PCE of 6.94% are obtained in the optimal DSSC with 10 wt% TNT-Au, significantly higher than those of the DSSC with pure TiO2 photoanode by 24.3% and 21.8%, respectively. These remarkable improvement in the properties of the DSSCs can be attributed to the strong scattering of TNT for incident light, fast charge transfer of TNT due to their unique one dimensional hollow structure, and the surface plasmon resonance of Au nanoparticles, in a tri-synergistic and complementary fashion.