Carbon black/silicon nitride nanocomposites as high-efficiency counter electrodes for dye-sensitized solar cells†
Abstract
A carbon black–silicon nitride (CB–Si3N4) nanocomposite is prepared as a cost-effective counter electrode (CE) for dye-sensitized solar cells (DSSCs). The CB–Si3N4 nanocomposite is coated on an FTO substrate via the screen printing method. The results demonstrate that when the thickness is fixed at 4.7 μm the CB–Si3N4 composite CE exhibits lower charge transfer resistance and higher electrocatalytic activity towards the reduction of tri-iodide over the CB and Si3N4 electrodes. The CB–Si3N4-3% CE achieves the best catalytic activity and the prepared DSSC shows a power conversion efficiency of 8.06%. As the thickness of the CB–Si3N4-3% CE increases, the electrocatalytic ability is enhanced, and the charge transfer resistance at the electrolyte/CE interface decreases. The overall performance of the CB–Si3N4-3% CE with a thickness of 14.1 μm is comparable to that of Pt-doped CEs. Furthermore, a DSSC equipped with CB–Si3N4-3% CEs of 14.1 μm thickness exhibits a high efficiency of 8.37%, which is comparable to that of the Pt-based DSSC (8.50%). The simple preparation technique, outstanding electrocatalytic activity, and low cost of production allow the CB–Si3N4 nanocomposite to be a promising and efficient CE for DSSCs.