Stabilized Conversion Efficiency and Dye-Sensitized Solar Cells from Beta vulgaris Pigment

Dye-Sensitized Solar Cells (DSSCs), based on TiO2 and assembled using a dye from Beta vulgaris extract (BVE) with Tetraethylorthosilicate (TEOS), are reported. The dye BVE/TEOS increased its UV resistance, rendering an increase in the cell lifetime; the performance of these solar cells was compared to those prepared with BVE without TEOS. The efficiency eta for the solar energy conversion was, for BVE and BVE/TEOS, of 0.89% +/- 0.006% and 0.68% +/- 0.006% with a current density Jsc of 2.71 +/- 0.003 mA/cm(2) and 2.08 +/- 0.003 mA/cm(2), respectively, using in both cases an irradiation of 100 mW/cm(2) at 25 degrees C. The efficiency of the BVE solar cell dropped from 0.9 +/- 0.006 to 0.85 +/- 0.006 after 72 h of operation, whereas for the BVE/TEOS, the efficiency remained practically constant in the same period of time.