New refrigeration coatings improve solar cell efficiency.

china Coatings Network
News:
A research team led by Professor Fan Wei of Stanford University in the United States has recently developed a transparent refrigeration coating material that can cool solar panels without affecting their sun absorption properties, thereby improving the efficiency and durability of solar cells.
Fan Wei team reported in the Proceedings of the National Academy of Sciences on the 21st, they used micro-processing technology on the silicon dioxide sheet etching micron-scale holes, designed a silicon dioxide photonic crystal coating material. This material is transparent to visible light, but has a strong thermal radiation capacity. Solar panels that use this coating absorb the same amount of sunlight while lowering the temperature.
told Xinhua that the crystals are passively cooled and do not require electricity or input from any other energy. The basic principle is to let the wavelength of about 10 microns of thermal radiation spread into the air, because this wavelength of thermal radiation will not be absorbed by the atmosphere, blocking, so as to be able to cool solar panels. In nature, this type of refrigeration is common.
tests on silicon chips showed that the crystals could reduce the temperature of the wafers by 13 degrees Celsius. 'Solar cells don't convert all the sun they absorb into electricity, they don't turn into heat, ' Mr. Fan said. The hotter the solar cell, the less efficient it is. If solar panels can be reduced by 13 degrees Celsius, they will be 1% more efficient. For decades, a 0.1% increase in the efficiency of commercial silicon-based solar cells has been a big step forward, and today its overall efficiency is only about 20%, so a 1% increase would be "very, very big".
Fan said that traditionally when people consider cooling solar cells, they mainly consider cooling them in the visible light band, and few people consider the far infrared band of 10 microns, so it is a big shift in design thinking. In addition, the relevant manufacturing processes are standard in industry and have little impact on the cost of solar panels.
addition to cooling solar cells, the coating material can also cool many other outdoor devices or electronic devices, said Zhu Linxiao, the first author of the paper and part of Fan's team. For example, the car in the sun for a while will be very hot, which brings some safety problems, but also the next time the car's air conditioning needs to spend a lot of electricity to cool down. With their coating material, the color of the car will not change, but its temperature can be greatly reduced, thus saving energy and so on.