The preparation of hierarchical rutile TiO2 microspheres constructed with branched nanorods for efficient dye-sensitized solar cells

Scattering capability has great impact on the photovoltaic performance of dye sensitized solar cells (DSSCs) for the improved light harvesting efficiency and reduced dosage of dye molecules. Herein, we report a simple two-step solvothermal method for the preparation of hierarchical rutile TiO2 microspheres constructed with branched nanorods (BMS). Compared with hierarchical rutile TiO2 microspheres constructed with nanorods (MS), BMS possess larger surface area and stronger light scattering capability. With BMS as scattering centers embedded into photoanode, the light scattering capability and electron transport have been improved. The optimal conversion efficiency of 6.66% has been obtained, with short-circuit current density and open circuit voltage at 11.9 mA/cm2 and 767 mV, respectively, significantly higher than that of pure P25 film based photoanodes (4.10%). Furthermore, the dosage of dye molecules has been greatly decreased in this efficient DSSCs. This photovoltaic performance could be attributed to the enhanced light scattering capability, improved electron transport and reduced charge recombination. The strategy would be favor for efficient DSSCs.