Enhance cell performance of DSSC by dye mixture, carbon nanotube and post TiCl₄ treatment along with degradation study

This study employs betalain extract from beetroot and curcumin extract from turmeric as sensitizer source for TiO₂ based dye-sensitized solar cell (DSSC) that has completely different absorption spectrum. The dye mixture has shown a wider absorption spectrum and higher light absorption than single individual dye. As a result, DSSC co-sensitized by the combination of dyes has shown enhanced cell performance. According to experimental results, DSSC sensitized by betalain and curcumin dye yield cell efficiency of 0.220% and 0.473% respectively. DSSCs have been co-sensitized with the mixture of dyes at 3 different volume ratios (1:1, 1:2 and 2:1) to find the optimized combination. The optimized mixture of betalain and curcumin dye (at 1:2 volume ratio) yields the maximum efficiency of 0.649%. The cell efficiency can be further improved by the incorporation of single-walled carbon nanotubes (SWCNTs) and post TiCl₄ treatment. DSSC fabricated with FTO/SWCNT-TiO₂ and TiCl₄ treated FTO/SWCNT-TiO₂ sensitized with the optimized dye mixture has the cell efficiency of 0.903% and 1.108%, respectively. Finally, the cell performance degradation has been measured by maturing the dye for 360 h in the normal atmospheric condition.