Application of a polymer heterojunction in dye-sensitized solar cells

Using a blend heterojunction consisting of a C60 derivative, [6,6]-phenyl-C61-butyric acid methyl ester (PCBM), and poly(3-hexylthiophene) (P3HT) as a charge carrier transfer medium to replace the I3−/I− redox electrolyte, a novel TiO2/dye/PCBM/P3HT dye-sensitized solar cell was fabricated and characterized. It was found that the P3HT/PCBM heterojunction widened the incident light harvest range from ultraviolet to visible light, and improved the photoelectrical response of the dye-sensitized solar cell. We investigated the influence of the PCBM/P3HT ratio and barrier layer on the photoelectric performance of the solar cell and proposed optimized preparation conditions. The optimized solar cell with a barrier layer and PCBM/P3HT ratio of 1:2 had a short circuit current density of 5.52 mA cm−2, an open circuit voltage of 0.87 V, a fill factor of 0.640 and a light-to-electric energy conversion efficiency of 3.09% under a simulated solar light irradiation of 100 mW cm−2.