Photoelectric evaluation of dye-sensitized solar cells based on prodigiosin pigment derived from Serratia marcescens 11E

Prodigiosin, a natural pigment produced as a secondary metabolite by the non-photosynthetic bacterium Serratia marcescens, was tested as a sensitizer in dye-sensitized solar cells (DSSC). The strain S. marcescens 11E, which was isolated from a natural spring located in the northeastern Mexican state of Nuevo Leon, was cultivated on peanut oil broth 1% v/v, a culture medium which is known to enhance the production of prodigiosin. The resulting pigment was extracted with chloroform and identified as pmdigiosin based on the spectroscopic and structural characteristics obtained by UV-Vis spectrophotometry along with FTIR and 1H NMR spectroscopies. The initial absorbance decomposition test performed on the bacterial pigment demonstrated that prodigiosin exhibited high photostability after five days, while the photovoltaic performance test of the sensitized DSSC, resulted in an open voltage circuit of 560 mV, a current density of 0.096 mA/cm(2), and efficiency of 0.032%. Structurally, the DSSC consisted of a titanium dioxide (TiO2) photoanode sensitized with the pigment by direct adsorption, an electrolyte containing a redox pair I-/I3- and a cathode or counter electrode prepared from a carbon paste. Since the overproduction of prodigiosin can be easily achieved on a large scale through the rapid fermentation of agroindustrial residues throughout the year without the need to allocate surfaces for the cultivation of pigment-producing plants or wait for specific seasons for their cultivation, our results suggest that prodigiosin could be considered an excellent candidate to be used in the development of a low-tech, low-cost DSSC.