In a study published this week in the Small journal, University of British Columbia (UBC) researchers successfully re-engineered the E.coli bacteria to power solar cells. The result saw cells that generated stronger current compared to that of similar biogenic attempts in the past and were capable of working even under dim light.
An impressive current density
The researchers reported an impressive recorded current density of 0.686 milliamps per sq cm, significantly higher than the 0.362 achieved by others in the field. These improved cells are also ideal in conditions such as overcast skies often found in British Columbia (BC).
“Our solution to a uniquely B.C. problem is a significant step toward making solar energy more economical,” said in a statement Vikramaditya Yadav, a professor in UBC’s department of chemical and biological engineering who led the project.
Solar cells, the building blocks of solar panels, are responsible for converting light into electrical current. However, most attempts to produce biogenic solar cells so far have centered around extracting the natural dye that bacteria use for photosynthesis, an expensive inconvenient process that includes the dangerous use of toxic components.
UBC's researchers took a different approach that saw them leave the dye in the bacteria and, instead, genetically engineered the E. coli to produce unusually large amounts of lycopene, a powerful photoactive pigment. They then coated the new bacteria with a mineral consisting of TiO2 nanoparticles that acted as a semiconductor and further applied the resulting mixture to a glass surface in order to increase its photovoltaic (PV) response.
“We recorded the highest current density for a biogenic solar cell,” explained Yadav. “These hybrid materials that we are developing can be manufactured economically and sustainably, and, with sufficient optimization, could perform at comparable efficiencies as conventional solar cells.”
Better and cheaper
Yadav also estimates the innovative process may reduce the cost of bacterial dye production by up to one-tenth. His team is now investigating a process that would salvage the bacteria allowing them to generate dye indefinitely, a solution he refers to as the "holy grail."
"This work lays strong foundations for the development of bio‐PV materials and next‐generation organic optoelectronics that are green, inexpensive, and easy to manufacture," states the study. Furthermore, the work may also have many varied future potential applications particularly in low-light environments such as mining or deep-sea exploration.
This is not the only good news for solar cells to come out this week. A new study published in Advanced Materials Interfaces demonstrated that polymer plastic solar cells could also be more efficient and have more stability than traditional ones.
From bacteria to plastic, it seems there is a race for the next material to rule the solar cell world. Luckily, in this competition, the environment and clean energy are all winners.