Cobalt Sulphate as an Alternative Counter Electrode Material in Dye Sensitized Solar Cells

Dye sensitized solar cells (DSSCs) have become an attractive and cheap device for the conversion of solar light into electrical energy. The glass substrate coated with platinum is widely used as a counter electrode because of its high catalytic activity for iodide/triiodide redox reaction. This paper presents a systematic comparative study on exploring and understanding the performance of DSSC using cobalt sulphate as a counter electrode material in place of platinum or graphite. However, platinum being costly, other materials like graphite or carbon black etc. also used in DSSCs but with reduced conversion efficiency. Later in the present study, it was found that, the DSSCs made with graphite as a counter electrode does not have long term stability. It may be mentioned here that cobalt sulphate so far has never been used as a counter electrode in DSSC fabrication. It is found that DSSCs made with the cobalt sulphate as a counter electrode gives better photovoltaic performance over that with the graphite-coated counter electrode and can be a suitable alternative for DSSCs in future. The paper also presents a comparative study on the performance degradation of DSSCs using cobalt sulphate and graphite as a counter electrodes. The investigation was carried out initially for 60 days in succession and then after 1 yr without charging with dye or electrolyte. Good long term stability of the cobalt sulphate compared to graphite was observed during this study.