Solar energy is setting off a future energy revolution, but it also has a big defect: rainy days always darken the light. Although raindrops help to clean up the stains and dust of solar panels, they will also greatly reduce the power generation efficiency, and the power generated is enough to ignore.
Because photovoltaic power generation is a device that uses the radiation of sunlight to convert direct current through photovoltaic modules, and then converts it into alternating current by inverter, and measures the power consumption through a distribution box and two-way electricity meter. In this principle, it all begins with sunlight. Without sunlight, there will be nothing in photovoltaic power generation.
In order to solve this problem, as early as 2016, scientists from the Ocean University of China and Yunnan Normal University developed a solar panel that can generate electricity on rainy days.
So how does rain generate electricity? The principle is like this. Raindrops are not pure water. Raindrops contain various salts. Generally, there are two types, one is an anion and the other is a cation. In order to generate voltage, the researchers instead covered the solar panels with graphene nanosheets with atomic thickness.
The electrons of graphene can attract positive charges in water, such as sodium ions, calcium ions, and ammonia ions. This will cause the surface water to store energy like a capacitor. When the capacitor stores energy, the positive and negative ions are layered. In this way, the solar cell can use the characteristics of graphene to generate electricity on rainy days.
Based on the above principles, the researchers added graphene to ordinary solar cells to make dye-sensitized solar cells. This is a cheap thin-film solar cell. On this basis, the researchers improved it by adding indium tin oxide and transparent backing. The final flexible solar cells show a photoelectric conversion efficiency of up to 6.53%. Although 6.53% is not a significant conversion rate, some panels have reached a conversion rate of 22.5%, but this is much better than nothing.
At the same time, there will be 100 microvolts of electricity when it rains. Although there is still a certain gap with the conversion rate of photovoltaic cell modules, the ability to generate electricity on rainy days has greatly improved the efficiency of the photovoltaic power generation systems.
Moreover, in areas with serious air pollution and haze, there will be all kinds of high concentration ions in the rain, and the power generation efficiency will be higher on rainy days.
The progress of science and technology is endless. Recently, researchers at the University of British Columbia announced that they had found a new bio solar cell technology, which can be used even on rainy days. This kind of solar cell made by bacteria converts sunlight into energy. The current generated by this solar cell is stronger than any similar device previously recorded, and it is equally effective in both strong and weak light environments.
Researchers genetically edit E. coli to produce a large amount of lycopene. This dye gives tomatoes a red-orange color, and this dye is particularly efficient in converting light into energy. The researchers coated E. coli with minerals to act as semiconductors and placed it on a glass surface.
The researchers used coated glass as an electrode of solar cells. Their device obtained a current density of 0.686 Ma per square millimeter, which is 0.362 Ma higher than other biological solar cells in the field. Yadav, the project leader, said: “We have set a record for the highest current density of biological solar cells. These hybrid materials we have developed are low-cost and sustainable, and after sufficient optimization, their conversion efficiency can be compared with that of traditional solar cells.”
Although the cost savings of this technology are difficult to estimate, Yadav believes that this process reduces the cost of dye extraction by one-tenth. Yadav said that the focus of this study is that we have found a process that does not kill bacteria, so they can make biological dyes indefinitely. This bio solar cell technology also has other potential applications, such as mining, deep-sea exploration, and other low light environments.
The exploration of clean energy has always been the constant goal of mankind. In today’s increasingly poor environment, it is necessary to use various forms of energy to prevent a more serious greenhouse effects. Any energy progress is gratifying. At least, it gives people more possibilities to live.
