Very high efficiency of low cost graphite-based solar cell by improving the fill factor using optimal ion concentration in polymer electrolyte

TL;DR

This study presents a low-cost graphite-based solar cell with nearly 7% efficiency, achieved by optimizing ion concentration in the polymer electrolyte and utilizing mineral water to enhance electron transport.

Contribution

The paper introduces a simple, low-cost method to improve graphite solar cell efficiency by using mineral water and optimizing ion concentration in polymer electrolyte, with a new efficiency equation.

Findings

Maximum efficiency reached 6.97%.

Mineral water induces fibrous structures aiding electron transport.

Efficiency correlates strongly with polymer conductivity.

Abstract

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