Modification of Dye-Sensitized Solar Cells With Sputter-Deposited Titanium Dioxide Blocking Layer for Enhanced Photovoltaic Performance Under Different Illuminations

In this study, the titanium dioxide (TiO2) thin film prepared by radio frequency magnetron sputtering system (R.F. sputtering) was used as the blocking layer (BL) of DSSCs. TiO2 blocking layer (TBL) is used to reduce the recombination reaction caused by contacting the oxidized electrolyte with the fluorine-doped tin oxide (FTO) substrate through the active layer with porous structure. We analyzed the effect of TBL introduction on the electrochemical impedance between photoanodes by potentiostat and calculated the electron lifetime, which proved that TBL can effectively improve the process of electron transfer. In addition, the direct impact of TBL on the photovoltaic performance of DSSC was determined through the quantum efficiency (QE) measurement system and current density-voltage (J-V) measurement system, and it was found that the short-circuit current density (
$\text{J}_{\mathrm {SC}}$
), external quantum efficiency (EQE), fill factor (FF) and photoelectric conversion efficiency (PCE) were all improved. DSSCs with TBL also exhibited better performance under low illumination due to the reduced recombination reaction. Further improves the applicability of DSSCs under low illumination.