Co0.85Se hollow nanoparticles as Pt-free counter electrode materials for dye-sensitized solar cells

• Co0.85Se hollow nanoparticles are synthesized by a one-step solvothermal method.
• Co0.85Se films are fabricated by a low-temperature spray deposition.
• Co0.85Se CE shows the similar catalytic activity with Pt for the I3− reduction.
• The power conversion efficiency of the DSSC with Co0.85Se CE is up to 6.03%.

In this paper, Co0.85Se hollow nanoparticles have been successfully synthesized by a one-step solvothermal method. The Co0.85Se counter electrode (Co0.85Se CE) has been fabricated and used for dye-sensitized solar cells (DSSCs). The electrocatalytic activity of CEs has been characterized by cyclic voltammetry, Tafel-polarization curves, and electrochemical impedance spectroscopy. The results indicate that Co0.85Se CE with a large surface area shows the high electrocatalytic activity for the reduction of I3−. The power conversion efficiency of the DSSC based on Co0.85Se CE is obtained up to 6.03%, which is slightly lower than that of the DSSC based on Pt CE (6.45%).

Co0.85Se film shows the similar catalytic activity with Pt for the I3− reduction, and the best performance of the DSSC based on Co0.85Se CE is achieved with the open-circuit voltage of 0.66 V, the short-circuit current density of 13.44 mA cm−2, and the power conversion efficiency of 6.03%.Figure optionsDownload as PowerPoint slide