Lithium perchlorate-assisted electrodeposition of CoS catalyst surpassing the performance of platinum in dye sensitized solar cell

Abstract

At the present work, cobalt sulfide (CoS)-based counter electrode (CE) synthesized by electrodeposition process in a deposition bath containing lithium perchlorate (LP) was employed in architecture of dye sensitized solar cell (DSSC). It was revealed that the LP can enhance the formation of CoS, while suppressing the formation of passive film within the deposit. Furthermore, LP differed the growth mechanism of CoS, resulting in honeycomb-like morphology. As a result of these, the electronic conductivity, active surface area and electrochemical/mechanical stability of CoS film have been improved, thus leading to a lower charge transfer and series resistances and an excellent electrocatalytic activity in comparison with Pt CE. The DSSC using CoS CE exhibited a higher power conversion efficiency (PCE) of 7.14% in comparison to 6.24% for DSSC with the Pt CE under solar irradiation of 100 mW/cm(2). Furthermore, consecutive cyclic voltammogram scans and stability test under solar irradiation proven that DSSC with CS-LP CE had superb long-term stability. Therefore, the electro-deposited CoS film in presence of LP can be contemplated as a promising catalyst material instead of expensive Pt for utilizing in DSSC owing to its excellent electrocatalytic properties and electrochemical/mechanical stability.