Potentiostatic deposition of cobalt nickel selenides on FTO for advanced dye-sensitized solar cells

Abstract Transition metal selenides are becoming increasingly prominent as promising catalytic materials in energy conversion and storage fields. However, the effect of ternary cobalt nickel selenides (Co-Ni-Ses) on the photovoltaic performance of dye-sensitized solar cells needs to be further explored. Here, Co-Ni-Se films have been designed and fabricated in situ on the conductive glass via potentiostatic deposition technology. The Co/Ni ratio of Co-Ni-Se films can be determined by changing the molar ratios of Co and Ni ions in the electroplating solution under the condition of fixing the total amount of metal and selenium sources. Then, Co-Ni-Se films are directly applied as low-cost counter electrodes of dye-sensitized solar cells. The results from electrochemical measurements reveal that Co-Ni-Se counter electrodes exhibit excellent electrocatalytic performance, which can be attributed to the synergistic effect between Co and Ni ions in Co-Ni-Se films. The effect of the Co/Ni ratio on the photovoltaic performance of dye-sensitized solar cells has been systematically studied, and it has been found that dye-sensitized solar cells based on Co-Ni-Se counter electrodes display impressive photovoltaic performance. The best power conversion efficiency of 7.38% was achieved under AM 1.5 G (100 mW cm−2) illumination for the dye-sensitized solar cells based on Co-Ni-Se-1:1 counter electrode, which was higher than that of the dye-sensitized solar cells with Pt counter electrode (6.73%).