Enhanced Efficiency of Dye-Sensitized Solar Cells via CuSCN Surface Modification on Platinum Counter Electrodes

Platinum (Pt)-based counter electrodes have been widely used in dye-sensitized solar cells (DSSCs) due to their excellent electrocatalytic properties for reducing iodide/triiodide (I/I3) redox couple electrolyte. However, Pt suffers from dissolution into the electrolyte, leading to redeposition onto the TiO2 film or conducting substrate, creating recombination centers, increasing series resistance, and reducing efficiency. To address these issues, CuSCN surface modification was investigated as a strategy to enhance DSSC performance. CuSCN layers were deposited onto Pt using two solvents, DMSO and NH₄OH, to evaluate their impact. Current density-voltage measurements showed that the device employing a single CuSCN layer dissolved in NH₄OH (N1x) achieved the highest power conversion efficiency (PCE) of 6.75%, compared to 5.183% for the reference device. Further characterization revealed that the N1x-based device exhibited longer electron lifetime, improved charge transport, and enhanced charge carrier diffusion length. Electrochemical impedance spectroscopy confirmed lower charge transfer resistance at both the counter electrode and photoanode. Additionally, cyclic voltammetry demonstrated a higher cathodic peak current density and lower peak-to-peak separation for the N1x-based counter electrode, indicating superior catalytic activity. These findings highlight the potential of CuSCN surface modification in improving charge extraction and electrochemical performance, ultimately enhancing DSSC efficiency. This study underscores CuSCN’s role in advancing efficient solar energy technologies.