Is it possible to further ascend the conversion efficiency of silicon solar? US scientists have recently replaced the top glass layer of a solar panel with a “pyramid lens” that acts as an internal daylight tracking system, which significantly improves the amount of light being captured by solar panels.  

The working hours of solar panels are usually in line with insolation, and have to also take into account the weather conditions, with merely several hours of energy output each day, which is why scientists are dedicated in increasing the working efficiency of solar panels.

A research team at Stanford University has developed a new auxiliary technology for solar cells by replacing the top glass layer of solar panels with a pyramid-like axially graded index lens (AGILE) that absorbs and centralizes sunlight from all angles, before injecting the sunlight into the cell.

The prototype of AGILE managed to capture more than 90% of light that was reflected onto the surface of the solar panel during the test, and the brightness that arrived at the cell after the light was focused was three times brighter than usual. The research team commented that AGILE is able to elevate conversion efficiency of solar cells indirectly, and helps with increasing the level of power generation on gloomy days.

With that being said, the engineering of AGILE is quite complicated, since each tiny pyramid is formed with polymers of different glass and refractive index, and the research team has to make sure that these materials do not interfere with one another, such as inflating in a similar speed when being heated, which allows the angle of the light to change consecutively and render a curve when being reflected onto medium of different refractive indexes. The top of the lens has the lowest refractive index, and while light can enter through any angle, it curves a bit more with each step it takes, before it is focused on the solar cell at the bottom.

The lateral side of the pyramid is a mirror that primarily reflects light. As pointed out by the research team, the equipment is able to capture light from near ultraviolet to infrared through various materials, and AGILE can conduct 3D printing even multiple materials are applied.

The team at Stanford University commented that the new system can help with increasing the generation of solar power, which further lowers the corresponding cost and required land, and may possibly improve the technology of aerospace solar panels.

 (Photo source: Stanford University)