Pumpkin stem-derived activated carbons as counter electrodes for dye-sensitized solar cells

Activated carbons (ACs) with a high surface area have been prepared from pumpkin stem wastes, using a simple and eco-friendly method. The as-prepared samples were characterized by field-emission scanning electron microscopy, high-resolution transmission electron microscopy, CHNS elemental analysis, and Raman spectroscopy. Furthermore, the AC samples were coated on indium tin oxide (ITO) substrates by the doctor blade technique and were used as counter electrodes (CEs) for dye sensitized solar cells (DSSCs). The fabricated DSSCs with AC counter electrodes showed a high power conversion efficiency of 2.79%. Notably, the excellent performance of the dye-sensitized solar cells fabricated with AC modified CEs surpassed that of several carbon-based counter electrodes in the literature.