Enhanced dye illumination in dye-sensitized solar cells using TiO 2 /GeO 2 photo-anodes

Dye illumination is a core factor in enhancing the electron density in the conduction band of TiO2 nanocrystallites and therefore also affects the power conversion efficiency of dye-sensitized solar cells (DSSCs). We investigated the use of anodes composed of TiO2/GeO2 nanocrystallites in DSSCs with the aim of increasing the power conversion efficiency. The interference effects from light reflected from the TiO2/GeO2 and GeO2/electrolyte interfaces significantly enhanced the intensity of the light used to illuminate the dye. We found an optimum power conversion efficiency of 7.91% (measured under standard AM 1.5 test conditions) in the DSSC using TiO2/0.5 wt% GeO2 nanocrystallites compared with 6.05% in a DSSC based on pure TiO2, an efficiency enhancement of 30.7%. This strategy provides a new opportunity for the fabrication of highly efficient DSSCs and the efficiency could be further improved using scalable techniques and components.