Scientists are developing a type of solar cells that can capture both solar energy and kinetic energy from water, which means it can generate electricity from raindrops.
In the past decade, solar battery systems have been used widely due to the increasingly cheaper installation costs, which have been 90% cheaper than in the beginning. This is also the reason why solar power has become the cheapest type of electricity in many regions in the world. However, there still exists a hard-to-solve problem, which is the “unstoppable decline” in the performance of solar panels when it is cloudy. Due to this fact, researchers are trying to find ways to make solar cells produce more electricity.
At Suzhou University, China, scientists placed two layers of transparent polymers on the solar panels. When raindrops fall on these layers and roll down, the friction force will produce static electricity. Therefore, this device can produce electricity day and night, as long as it is sunny or rainy.
Another group of researchers have also created a similar device for solar panels called nano friction generator or Teng (triboelectric nanogenerator). The device has a much simpler structure than the above-mentioned, but gives higher performance. This is the result of using one of the polymer layers as the electrode for both Teng and solar cells. Due to the special design, the Teng is very light. In the future, the team plans to apply this technology into mobile devices and flexible materials such as e-cloth. However, the efficiency of the output power needs to be further improved before it is applied into practical use. A member of the research team said the project was progressing smoothly and promised to launch the samples within the next 3 to 5 years.
Several other Chinese scientists have also used Teng on solar cells to get wind energy. The top layer of the Teng is also grooved to help focus more light on the solar cells.
Mr. Varun Sivaram is a member of the US Diplomatic Council and the author of “Taming the Sun”: Innovations to Harness Solar Energy and Power the Planet – a new book published by the Massachusetts Institute of Technology (MIT) last month. Varun said, “The idea about the Teng was extremely interesting. It is a hybrid device that allows the acquisition of kinetic energy from water without affecting the electricity production capacity of solar cells when it is sunny. Only one layer is needed for two tasks at the same time but it could collect more sunlight. Such a wonderful new technology.” However, Varun also expressed his opinion that the amount of electricity generated from rainwater must increase significantly in order to have a distinct difference compared to the existing solar cells.
Professor Keith Barnham from the Imperial College London said that the Teng makes solar cells more compact and more efficient by collecting energy from a variety of weather patterns. However, it is clear that wind power is the most potential source of energy for solar cells because there is always wind whether it is sunny or rainy.
Currently, there are many other new and innovative features in designing solar cells, such as the use of inorganic perovskite as the production material to create flexibility and bring high efficiency, the use of “quantum dots” and the study of the artificial photosynthesis process using sunlight to create energy in the forms of liquid and gas.
With the new type of solar cell, the amount of the obtained power is always stable despite cloudy weather or sunset. However, it still takes a few more years for this technology to be officially completed.
