Multi-colored dye-sensitized solar cells

Multi-colored solar cells sensitized with organic dyes were developed by optimizing electrolytes and counter electrodes to enhance the transparence of the both by reducing the concentration of iodine dissolved in the imidazolium-based electrolytes and by employing a platinum layer of a 0.5 nm thickness. The solar cells were assembled by using nano-crystalline TiO2 electrodes adsorbing sensitizing dyes, an electrolyte consisting of a mixture of iodine and 1-butyl-3-methylimidazolium iodide in a 0.2:10 molar ratio and the counter platinum electrode to give cells bearing red, purple, blue, green and black colors. The multi-colored solar cells were connected in series to exhibit a 2.1% conversion efficiency under AM 1.5 (1 sun, 100 mW cm−2) irradiation with a total semiconductor area of 25 cm2.