Study on the performance of dye sensitized solar cells using 29 natural dyes as sensitizer

Natural dyes were extracted from 29 kinds of natural plants using ultrasonic method. Uv-vis absorption spectra of these natural dyes were tested and pigments contained in these natural dyes were discussed. TiO2 film electrodes were prepared by hydrothermal method, TiO2 photoelectrodes were sensitized by 29 kinds of natural dyes and then they were fabricated to dye sensitized solar cells (DSSCs). The photoelectric performance of DSSCs sensitized by these dyes was tested. The experimental results indicate that the open circuit voltages (Voc) vary from 0.46 V to 0.64 V and the short circuit photocurrent densities (Isc) range from 0.04 mA · cm-2 to 3.61 mA · cm-2. Specifically, the DSSC sensitized by mangosteen pericarp dye has optimum photoelectric performance, whose short circuit photocurrent density and photoelectric conversion efficiency (η) are 3.61 mA · cm-2 and 2.13%, respectively. Seven kinds of dyes with different absorption bands of pigment were picked out and mixed with each other for Collaborative sensitizer. UV-vis absorption spectra show that absorption peaks of these mixed dyes usually have a small offset. The test results of photoelectric properties show that the photoelectric conversion efficiency of DSSC sensitized by mixed natrual dyes is between those of DSSCs sensitized by single natural dyes. The photoelectric conversion efficiency of DSSC sensitized by mangosteen pericarp and kale reaches the highest value of 1.7%. Finally, the experimental results are analzsed carefully and the way to improve the photoeletric performance of DSSCs sensitized by natural dyes is discussed.