Effect of RF sputtered arc-TiO2 and sol-gel c-TiO2 compact layers on the performance of dye-sensitized solar cell

A novel gradient index antireflective TiO2 compact layer (arc-TiO2) that can improve transmittance and prevent charge recombination has been developed for dye-sensitized solar cells by radio frequency magnetron sputtering. Effects of the presence of arc-TiO2 compact layer to the performance improvement of a DSSC were compared to that of a sol-gel derived compact layer (c-TiO2) by means of incident photon-to-current efficiency (IPCE) and open-circuit voltage decay (OCVD). The higher and right-shifted transmittance spectra in the arc-TiO2 based electrode have improved the sensitization effect of the DSSC in a specific region as shown by IPCE measurement. The slow decay behavior of the photo-voltage attributed to the merits brought by the arc-TiO2 and c-TiO2 compact layer has been evidenced by the OCVD measurement. An improvement in the overall conversion efficiency of 7% increment compared to the cell with c-TiO2 compact layer is mainly responsible for the higher transmittance and fewer recombination effects of the arc-TiO2 compact layer employed in the DSSC.