Investigation of the TiO2 nanoparticles aggregation with high light harvesting for high-efficiency dye-sensitized solar cells

The TiO 2 nanoparticles aggregation (TNA) was synthesized by a novel one-step hydrothermal method in this work. And for the first time we prepared a kind of jelly pastes of TNA used as photoanode for high-efficiency dye-sensitized solar cells (DSSCs). The prepared TNA provides larger specific surface area of 79.34 m 2 g −1 compared with P25 nanoparticles (49.25 m 2 g −1 ), which is beneficial of absorbing more dye molecules and contributes to high current densities. Moreover, the high scattering effect of TNA caused a strong absorption in the visible-light range increasing the number of excited charges and reducing the energy loss. The effect of various concentrations of TNA pastes for DSSCs was studied to explore the superiority of concentrated TNA pastes. The result shows the DSSC based on high-concentration pastes and double-layer film achieved the best power conversion efficiency (PCE) of 8.34 % corresponding the current density of 17.97 mA cm -2 .