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.