US research and development of new refrigeration coatings can improve solar cell efficiency

A research team led by Professor Fan Shanhui at Stanford University in the United States recently invented a transparent and cooled coating material that can cool solar cells without affecting their solar absorption and improve the efficiency and durability of solar cells.

Fan Shan team on the 21st in the United States, "Proceedings of the National Academy of Sciences," on the report that they use micro-processing technology in the silica sheet etching micron-sized holes, designed a silica photonic crystal coating material. This material is transparent to visible light, but has a strong thermal radiation ability. Solar panels using this coating absorb as much sunlight as possible while lowering the temperature.

In an interview with Xinhua News Agency reporters, Fan Shanhui said that this kind of crystal is passive cooling and does not require electricity at work and does not require any other input of energy. Its basic principle is to make the heat radiation with the wavelength of about 10 microns diverge into the air, because the heat radiation of such wavelength can not be absorbed by the atmosphere and blocked, so as to be able to cool the solar panel. In nature, this cooling method is common.

Tests carried out on silicon show that the crystal can reduce the temperature of the silicon wafer by 13 degrees Celsius. Fan Shanshui said that solar cells will not absorb all the sunlight into electricity, there is no conversion into heat. The hotter the solar cell, the lower its efficiency. If the solar panel can be lowered by 13 degrees Celsius, then its efficiency will be increased by 1%. For decades, a 0.1% increase in the productivity of commercial silicon-based solar cells is a big step forward, and its overall efficiency is now only about 20%, so a 1% increase would be "a very, very big improvement."

Fan Shanhui said that when people consider the traditional cooling of solar cells, the main consideration in the visible band for its cooling, few people consider this 10-micron far-infrared band, so the design is a big idea change. In addition, the relevant manufacturing process in the industry are standard processes, the cost of solar panels has little effect.

Zhu Linxiao, the first author of the paper and Fan Shanning's team, said that in addition to cooling the solar cell, the coating material can cool many other outdoor devices or electronic devices. For example, the sun in the car for a while will be very hot, which brings some safety issues, also led to the next start when the car air conditioning need to consume a lot of electricity to cool down. The use of their coating materials, the car will not change any color, but its temperature can be significantly reduced, so as to save energy and so on.