Screen-printed carbon black/SiO2 composite counter electrodes for dye-sensitized solar cells

Platinum (Pt)-based counter electrodes (CEs) are promising electrocatalysts for dye-sensitized solar cells (DSSCs). However, replacing the expensive Pt with low-cost materials and comparable catalytic activity still a big challenge. Here, we prepared CB-SiO 2 composites by blending various weights of SiO 2 (1, 3, and 5 wt%) with carbon black (CB), followed by screen printed onto the FTO substrate to utilized as CEs for DSSCs. In comparison with pure CB, CB-SiO 2 composite CEs showed higher transferability and higher electrocatalytic activity toward I 3 - / I - ${\mathrm{I}}_3^{-}/{\mathrm{I}}^{-}$ redox couple. Among all, CB-SiO 2 -1% composite CE with 4 µm showed the best catalytic performance, and the related DSSC showed a power conversion efficiency of 6.38%. Increasing the CE thickness significantly enhances the catalytic ability and the total performance of the assembled devices, whereas the power conversion efficiency of the DSSC with CB-SiO 2 -1% composite CE in 8 µm thick was 7.99%, which is close to that achieved by Pt-based device under the same conditions.