Iron-nickel-cobalt selenide nanoparticles as an efficient and transparent counter electrode for dye-sensitized solar cells

In this study, we developed a quaternary metal selenide (Fe_0.35Ni_0.11Co_0.19Se) counter electrode (CE) material, grown onto fluorine-doped tin oxide, for dye-sensitized solar cells (DSSCs) using the potential-reversal electrochemical deposition technique at ambient conditions. Under optimized conditions, the Fe_0.35Ni_0.11Co_0.19Se CE exhibited excellent electrocatalytic activity in the I^-/I₃ ^- redox reaction with the average transmittance of 78.85 %. The additional valence states of Fe in the Ni_0.3Co_0.3Se electrode material further enhanced the catalytic activity during the electrochemical redox process. The DSSC employing this electrocatalytically active CE realized a power conversion efficiency of 7.73 %, surpassing the efficiency of both Pt and Ni_0.3Co_0.3Se CEs-based DSSCs (7.23 % and 7.23 %, respectively). This electro-preparation method offers a simpler and more cost-effective fabrication process for CE design, demonstrating a good potential for replacing expensive platinum CEs in DSSCs.