g-C 3 N 4 /conductive carbon black composite as Pt-free counter electrode in dye-sensitized solar cells

Abstract The composites of g-C 3 N 4 and conductive carbon black (CCB) were prepared by a simple ball-milling process and explored as the counter electrode for dye-sensitized solar cells (DSCs). The enhanced electrocatalytic activity for I 3 − reduction can be demonstrated when CCB was incorporated into g-C 3 N 4 . The charge-transfer resistance of g-C 3 N 4 /CCB (1:1, mass ratio) composite electrode was 2.4 Ω cm 2 , which is much lower than those of the individual g-C 3 N 4 and CCB electrodes, indicating predominant synergistic effect of g-C 3 N 4 and CCB in electrocatalytic activity. Under illumination of 100 mW cm −2 , the DSC with g-C 3 N 4 /CCB (1:1) composite counter electrode achieved a conversion efficiency of 5.09%, which is comparable to that of the cell with Pt counter electrode.