Bio-Photovoltaic Conversion Device Made from Chitosan Nanofibers and Varieties of Natural Pigments

In this study, the natural pigments anthocyanin, beta carotene, chlorophyll, and curcumin, extracted from red cabbage, carrot, water hyacinth and turmeric, respectively, were used as sensitized dyes in a Bio-photovoltaic Conversion Device (BPV), and the energy conversion efficiencies (η) were compared. The photoelectrodes were designed to use various photoactive layers made of porous TiO2 or a new TiO2:nanofiber interface. The nanofibers were prepared by an electrospinning chitosan solution, a PVA solution (poly(vinylalcohol)), and their mixture at different conditions. Analysis from a scanning electron microscope (SEM) showed that the formation and the density of nanofibers increase with increasing amount of PVA. The highest η was observed in solar cells which used anthocyanin extracted from red cabbage. When considering the photoactive layers made of TiO2:nanofibers prepared from the mixture between 1.2 % chitosan in acetic acid and 8 % PVA in aqueous solution at the ratio of 1:1. w/w ([1.2Chitosan]+[8PVA]), it raised the η up to 5.3 times higher than by the TiO2 alone. Therefore, the utilization of chitosan nanofibers together with the application of natural dyes has the potential to increase η of BPVs