Extraction and Characterization of Apocarotenoids (Cis-Norbixin and Cis- Bixin) as Natural Sensitizers for Dye-Sensitized Solar Cells

We present a study on dye-sensitized solar cells (DSCs) based on apocarotenoids extracted from Achiote (Bixa orellana) a tropical shrub originating from the American continent. From the achiote seeds, we obtained a dark-red extract employing two new methods: one based on acetone and another based on diethyl ether. We studied the effect of the 4-tert-butyl-pyrydin on the sensitizer performances and the effect of the thickness of TiO2 layers. Bixin’s solar conversion efficiency was deeply improved by a progressive optimization of the photoanode TiO2 multilayer and of the electrolyte compositions overcoming the best performance reported in literature so far. It’s worth to emphasize that, although presently bixin based DSCs are still below the efficiency requirements for practical applications, our results indicate that these pigments are promising candidates to be potentially exploited, in the future, for production of non-toxic, cheap and fully biodegradable tandem dye-sensitized solar cells and as co-sensitizers since their absorption spectra is complementary to that of others dyes.