  We report the development of graphite-based solar cells using a simple method
and low cost materials. Suspension of graphite powder in mineral water was
simply dropped onto the surface of fluorine-doped tin oxide glass (FTO) to form
a thick film. Surprisingly, using mineral waters greatly improved the
efficiency of the solar cell to reach the highest efficiency of 6.97%. Due to
some minerals contained, the mineral water induced the development of fibrous
structure between the graphite particles which is assumed to play a role as a
bridge for the photoexcited electrons to quickly move to the electrode and
suppress recombination with holes. This efficiency is very attractive when
considering the materials used to develop the solar cell are all low cost.
Economically this may challenge the present high efficiency semiconductor-based
solar cells. We achieved the high efficiency by manipulating the cell fill
factor through optimizing the ion concentration in PVA.LiOH polymer
electrolyte. We also propose an equation to describe the effect of LiOH
concentration and efficiency and we also provide strong correlation between the
cell efficiency and the polymer conductivity

Applied Physics;Materials Science