The light absorption rate of thin film silicon photovoltaic cells reached a new record of 65%, close to the theoretical limit of 70%

Original title: 65%! Record of light absorption rate of thin film silicon photovoltaic cells

Close to the theoretical limit of 70%, it is expected to give birth to light and efficient silicon photovoltaic cells

Dutch and British scientists have used a nano textured structure to make thin-film silicon photovoltaic cells opaque and thus enhance their efficiency in absorbing sunlight. The experimental results show that the thin film cell designed by the new method can absorb 65% of the sunlight, which is the highest light absorption rate of the thin silicon film so far, close to the theoretical absorption limit of about 70%, and is expected to give birth to a flexible, lightweight and efficient silicon photovoltaic cell. The study was published in the journal photonics of the American Chemical Society.

Silicon solar cells have high efficiency, and the raw material is silicon with abundant reserves on earth. It is considered to be an efficient photovoltaic technology. However, they need thick, hard and heavy wafers, so their use is limited. The use of thin film can reduce the use of silicon by 99%, and make the battery lighter and more durable. It can be easily integrated into urban buildings and even small daily equipment. But the thin silicon film can only absorb 25% of the sunlight. In view of this, researchers from the Dutch National Institute of atomic and molecular research (amolf), the University of Surrey and Imperial College of technology have improved it.

The researchers explained that the nanostructure surface they designed with the new method has a super uniform distribution pattern, which can limit the direct sunlight to an angle range, so as to capture more light in the silicon film. The more light is captured, the more likely it is to be absorbed. The research shows that the super uniform distribution pattern can better limit the incident angle of sunlight and make more sunlight absorbed.

In addition, capturing sunlight into thin silicon faces two key challenges: sunlight contains multiple colors, while the size of silicon film is limited, and the absorption capacity of silicon for each color is different. It is found that thick silicon solar cells with pyramid shape and pattern size similar to the wavelength of light can solve this problem.

“We estimate that the photoelectric conversion efficiency of 1 micron thick carbon silicon cells can reach more than 20%, which is a major breakthrough in flexible lightweight carbon silicon photovoltaic cells. The study also found that high-efficiency thin silicon cells can be made of low-quality silicon, which can reduce the energy demand for purifying raw silicon and shorten the energy recovery time,” said Esther araken Lado of amolf, the leader of the latest research

The researchers pointed out that although this high-efficiency thin-film cell is still a long way from application, Ultra-uniform pattern thin-film photovoltaic cells have great potential.

This article is transferred from science and Technology Daily reporter Liu Xia