Fabrication of TiO2 based dye-sensitized solar cell with natural dyes

Abstract

A dye-sensitized solar cell (DSSC) belongs to thin film solar cells, based on a semiconductor formed between photoelectrode, electrolyte, and counter electrode which utilizes the benefit of the wide band gap semiconductor with dye absorbed on it, that sensitized to the light. At the heart of the device, a thick oriented nanorod film of titanium dioxide (TiO2) is present as wide bandgap semiconductor. The idea of the dye in DSSC is same as chlorophyll in leaves; as it absorbs a photon, dye molecules get excited and injects electron to a wide bandgap semiconductor(here TiO2) to generate electricity. DSSCs are assembled using abundant and inexpensive materials by economical methods. The work carried during this project aimed on optimizing the DSSC using two different strategies; by synthesizing TiO2 nanostructures for DSSCs photoelectrode and by checking the nature of dyes for DSSCs application. We used different natural dyes extracted from various plants, flowers, fruits, and measured their I-V characteristics. The best optical and photovoltaic performance in terms of efficiency and stability achieved with polypyridyl complexes of ruthenium and osmium, which are commercial dyes, but here natural dyeshas been used to construct Gratzel cells.