Highly Efficient Dye-Sensitized Solar Cells Based on Carbon Black Counter Electrodes

Abstract

Carbon black was employed as the catalyst for triiodide reduction on fluorine-doped tin oxide glass substrates (FTO-glass) used as counter electrodes in platinum-free dye-sensitized solar cells. The fill factors were strongly dependent on the thickness of the carbon layer, and the light energy conversion efficiency also increased up to a thickness of 10 um. The charge-transfer resistance (Rct) of the carbon counter electrode decreased with the thickness of the carbon layer. The Rct for the thicker carbon layer is less than three times that for the platinized FTO-glass. The highest cell efficiency was 9.1% under 100 mW cm2 light intensity (1 sun AM 1.5 light, Jsc = 16.8 mA cm2, Voc = 789.8 mV, fill factor = 0.685).