Naturals Dyes from Detarium Microcarpum Guill. and Perr. as Photosensitizers in Dye Sensitized Solar Cells

Abstract

Dye-sensitized solar cells (DSSC) are promising devices in the photovoltaic industry. In these devices, The dye plays a major role in the performance of the cell. However, the toxicity and cost of synthetic dyes, which are more effective, limit their use. Thus, the use of natural dyes is a promising alternative. In this article, natural dyes extracted from the trunk bark of Detarium Microcarpum Guill. and Perr (DM) were used, for the first time, in DSSC. Aqueous decoction followed by Hydro-acetonic extraction (30/70, V/V) was carried out to obtain the crude extract from the bark ground into a powder. Then a phytochemical screening of the crude extract followed by liquid-liquid separation and assay of the main colored compounds in order to evaluate the amount of total polyphenols, flavonoids and anthocyanins were carried out. The different separated fractions were tested as photosensitizers in DSSC.The extraction of the crude pigment from the bark of the trunk of Detarium Microcarpum gave a very interesting yield of 20.48% compared to others. The results of the phytochemical tests reveal the presence of the following compounds: catechic tannins, gallic tannins, flavonoids, anthocyanins, leuco anthocyanins, coumarins, quinones and alkaloids with high concentrations. The results of the photovoltaic tests of the different separate extracts show that the n-butanol extract is the most efficient. Cells sensitized with this extract showed a photocurrent (Jcc) of 0.93 mA/cm2, a high open circuit voltage (Voc) of 433 mV and a high conversion efficiency η (%) of 0.38%. This conversion efficiency is higher than that of a recent study which reported a conversion of 0.31%. These results show that Detarium Microcarpum constitutes a potential source of photosensitive dye.