Utilization of natural anthocyanin pigments as photosensitizers for dye-sensitized solar cells

Nanocrystalline TiO2 thin films have been prepared by sol–gel dip coating method. The X-ray diffraction results showed that TiO2 thin films annealed at 400, 450 and 500 °C are of anatase phase and the peak corresponding to the (1 0 1) plane is present in all the samples. The grain size of TiO2 thin films was found to increase with increasing annealing temperature. The grain size is found to be 20, 26 and 38 nm for the films annealed at 400, 450 and 500 °C. TiO2 thin films were sensitized by natural dyes extract from red cabbage and blue pea. It was found that the absorption peak of red cabbage extract is at about 545 nm while that of blue pea extract is at around 576 and 622 nm respectively. The dye sensitized TiO2 based solar cell sensitized using red cabbage, exhibited a Jsc of 4.38 mA/cm2, Voc of 0.47 V, FF of 0.36 and η of 0.73 % and the solar cell sensitized using blue pea, exhibited a Jsc of 4.16 mA/cm2, Voc of 0.45 V, FF of 0.35 and η of 0.67 %. Natural dyes as sensitizers for dye sensitized solar cells are promising because of their environmental friendliness, low-cost production and designable polychrome modules.