Solar energy can't generate electricity on cloudy days? This kind of bacteria is not convinced

When lycopene is stored in clear glass bottles, they degrade rapidly and are replaced by opaque bottles. The problem is solved, but this discovery has caused more scientific problems, researchers think, in chemistry, Degradation usually means releasing electrons. If the rate of electron release is high enough, can it produce a measurable current?

Solar power has many benefits, such as reducing the use of fossil fuels, being cleaner, inexhaustible, not producing carbon footprints, etc. But there are limitations, that is, there must be a sun, if it is cloudy, there is no way. Over.

Now, a genetically engineered bacterium that uses light to convert light into energy may change the situation that solar energy cannot be generated on a cloudy day. Scientists in British Columbia have built a cheap, sustainable source from E. coli. Solar cells, which created a bio-causing solar cell, were named because the battery was made up of organisms. This is not the first experimental biogenetic solar cell, but this time the battery Unlike in the past, scientists say the current battery can produce more powerful currents. Moreover, the battery can be as effective in bright sunlight in dim sunlight.

No matter what material, as long as it can react and release electrons under the sun, you can try to use it for solar power. In bio-solar cells, the material evoked by sunlight is biological. Under normal circumstances, solar panels use inorganic Crystalline silicon produces current, but now crystalline silicon is replaced by dye.

'British Columbia is eager to become one of the world's leading decarbonation economies,' said Vikramaditya Yadav, a professor of the Department of Chemical and Biological Engineering at the University of British Columbia. 'Clean energy production And supply is the key to achieving this goal, and solar energy is a major candidate for decarbonization in the energy sector. However, British Columbia has poor winter weather conditions. In this case, if you want to take advantage of solar energy, you need a unique Photovoltaic materials. '

Yadav said that their solutions are not expensive, and in the end 'can be as efficient as traditional photovoltaics.' Even if these new biological cells do not reach the strength of traditional materials, researchers still think these New materials can play an important role in some low-light environments, such as mines and deep-sea exploration.

'We believe that bio-cause solar cells will be a useful complement to inorganic solar cell technology,' said Yadaf. 'Even in the early stages of development, the application of this technology is clear and broad. Explore low-light environments, such as In mines, biological cell-driven sensors, such as those we developed, will be used.

Legend: The conceptual diagram above shows that the anode of a solar cell is made of biomaterial, which is made of orange globular bacteria coated with titanium dioxide on the surface of lycopene. (Photo / Vikramiyah Yadav)

Previously, attempts to build bio-solar cells focused on extracting natural dyes because bacteria needed these dyes for photosynthesis. The process was complex and costly, and toxic materials were used, which would cause damage to the dye. Canadian researchers decided Try a few different options. The researchers left the dye in the bacteria to interact with the organism to induce the bacteria to produce a lot of lycopene. This lycopene is the same as the dye found in tomatoes and other red waters.

Then, the researchers covered the bacteria with a layer of minerals that acted as a semiconductor and applied the mixture to the glass surface. Apply a layer of coated glass to the end of the cell as the anode, and the normal current would pass. This anode, the current density produced by this device is much greater than the current density produced by other experiments in the field. The specific value is 0.686 mA per square centimeter and 0.362 mA per square centimeter. The results of this test are published in In the journal "Small".

The use of photosensitizing dyes is not a new concept, but it has encountered obstacles in previous studies. In 1988, the Swiss scientist Michael Grötzel developed a solar cell using photosensitizing dyes. Dye-sensitized solar cell (DSSC).

'Most dye-sensitized solar cells have some obvious limitations,' said Yadav. 'The extraction of dyes from natural sources requires the use of toxic solvents and energy, and the sensitivity of the dye to light before entering the solar cell. There is significant degradation. The devices we developed directly address these limitations and try to put this solar cell into production, which is especially suitable for use in dark environments, and our devices are cheaper.'

Despite this, there are some problems with this device. Bacteria can die during power generation, so finding a way to make them survive can be used more efficiently because bacteria can produce dyes indefinitely. At the same time, researchers plan on cells. Fine-tuning to provide more energy like a traditional solar cell.

'Our invention is the first generation prototype, so the level of silicon solar cells needs to be greatly improved. The current density of silicon solar cells is 25 times that of our first prototype,' said Yadaf. 'We don't think our technology is a competitor to traditional solar cells. In any case, we can't reach the power generation level of traditional solar cells.'

Like many scientific discoveries in the past, this research is also accidental. 'Our initial motivation was to develop bacteria 'small factories' to produce large quantities of lycopene and other carotenoid molecules to make health supplements,' said Yadav. 'However, our team encountered a challenge in storing the newly produced lycopene.'

When lycopene is stored in transparent glass bottles, they degrade rapidly, so the researchers switch to opaque bottles. The problem is solved, but this discovery has caused more scientific problems, and the researchers opened up. A new way of exploring. 'In chemistry, degradation usually means releasing electrons. We think: If the rate of electron release is high enough, can it produce a measurable current?' said Yadav.

'A student in the research team, after seeing the change in lycopene in a transparent bottle, said loudly: 'How much is lycopene so degraded in the sun? What if we put it in a solar cell? 'This problem has aroused our interest in developing dye-sensitized solar cells,' recalled Yadav. 'The decision to use mineral coating directly on bacteria is a gamble, and this gamble is finally rewarded. It is a great ally of scientists. We are very grateful for this unexpected discovery and the curious student, because he asked, 'Why can't I try?'

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