Development of an Efficient Biosensitized Solar Cell Using Bacteriorhodopsin Producing Haloarchaeon Halobacterium Noricense

The escalating global demand for energy, coupled with the adverse environmental impacts of conventional energy sources, necessitates a paradigm shift towards cleaner and greener alternatives. Fossil fuel dependence and high carbon footprints from contemporary energy sources contribute significantly to global warming and climate change. Solar cells offer a promising avenue for sustainable energy production. Unlike traditional cells, solar cells leverage the photovoltaic effect in a P-N junction diode, converting light energy into electrical energy without relying on chemical reactions or fuel. The amalgamation of individual solar cells forms solar panels, which can efficiently harness the abundant and economical energy provided by the sun.

Biosensitized Solar Cells, as an alternative to traditional solar cells, employ Titanium Dioxide (TiO₂) electrodes and bacteriorhodopsin as a light-absorbing material. These cells can be seen as an enhancement of Dye-Sensitized Solar Cells, utilizing bacteriorhodopsin in place of traditional Ruthenium dyes. Bacteriorhodopsin is derived from Haloarchaea, specifically from hypersaline environments, where unique conditions foster the growth of these microorganisms. Haloarchaea, thriving in hypersaline environments, are known to produce bacteriorhodopsin, a light sensitive protein that converts light energy into electrochemical energy. Notably, Halovivax asiaticus, Halobacterium noricense and Halostagnicola larsenii are some haloarchaea which have been shown to yield substantial amounts of bacteriorhodopsin, offering a potential sustainable source for biosensitized solar cells.

Experiments involving bacteriorhodopsin harvested from cultures of Halostagnicola larsenii RG2.14 have demonstrated promising results. When immobilized on TiO₂ nanocrystalline films, the biosensitized solar cells exhibited an open-circuit voltage (OCV) of 0.52 V, photocurrent density of 120 μA/cm², and an overall efficiency of 0.11%. These findings underscore the viability of harnessing bacteriorhodopsin for solar energy conversion. The aim is to develop a lower cost biosensitized solar cell with minimal environmental impact while ensuring comparable efficiencies to traditional solar cells. In conclusion, this research offers a comprehensive exploration of biosensitized solar cells utilizing bacteriorhodopsin from haloarchaeon, Halobacterium noricense presenting a promising avenue for sustainable energy production. The outcomes of this study contribute to the ongoing global efforts towards cleaner and more efficient energy solutions. This paper explores the potential of biosensitized solar cells as a cost-effective and environmentally friendly solution to meet the rising energy demands.