Urea-Treated Electrolytes for Higher Efficiency Dye-Sensitized Solar Cells
27-12-2017 19:11
Urea was used as dopant for the triiodide/iodide electrolyte (I-/I3-) to increase the efficiencies of dye-sensitized solar cells (DSSCs). Different concentrations of urea at 0 wt%, 2 wt%, 5 wt%, 10 wt%, and 20 wt% were added to the electrolyte to improve overall DSSC performance. The optimal concentration was found at 10 wt%. Significant improvements were achieved in both open circuit voltage (Voc) and fill factor (FF) by increasing the urea wt%. Urea is a Brønsted–Lowry base, which has a lone pair of electrons. The power conversion efficiency (PCE %) was remarkably improved from ~ 8.5 % without urea to ~ 10.1 % for the optimal urea at 10 wt% in the electrolyte. The efficiency enhancement was attributed mainly to the decrease of triiodide (I3-) in the electrolyte due to the higher urea wt.% and the enhanced inter-molecular hydrogen bonding between the urea and electrolyte when the excess H+ was introduced to the electrolyte at a higher urea wt.%.