Dye-sensitized solar cells using natural dyes

Abstract

Dye-sensitized solar cells (DSCs) produced from synthetic dyes and nanometric-sized titanium dioxide (TiO2 ) have been given a great deal of attention and research. In this dissertation, DSCs constructed from 20 and 100 nm TiO2 particles, and using both natural and synthetic dyes, have been characterised. DSCs with different combinations of materials were constructed and characterised with the aim of finding the most efficient and cost-effective cell. The main parameters measured included current-voltage (IV) curves, short circuit current (ISC) and open circuit voltage (VOC) of the cells while illuminated. The response time of the cells was also obtained by measuring the VOC as a function of time before and after illumination. The dyes used were further chemically characterised by using ultraviolet/visible (UV/Vis) absorption spectra. The best performance with natural dyes was obtained from 100 nm TiO2 cells using a blueberry extract. This TiO2 layer was however very unstable on the conductive glass as opposed to the 20 nm TiO2. Cell performance of unsealed cells was found to vary greatly with time, the best performance being reached between 7 and 27 days after construction.