The solar scene is illuminated. And it’s blinding.
A team of researchers from the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) has created a solar cell with a record efficiency of 39.5% under global illumination from a sun, breaking the world efficiency record solar cells, according to a recent study. published in the journal Joule.
Amazingly, it has the highest efficiency recorded for any cell type ever measured under real conditions.
A record-breaking solar cell
The record was achieved in lighting conditions equivalent to sunlight, according to a press release. While earlier experimental solar cells have achieved efficiencies of up to 47.1%, it’s crucial to point out that they did so under extremely concentrated light. In fact, the world record for solar cell efficiency at 47.1% was reached in 2019, with researchers using multi-junction concentrator solar cells developed at the National Renewable Energy Laboratory.
The solar cell has also been tested for its potential in space, particularly to power communications satellites, which are powered by solar cells and require high cell efficiency. Under such conditions, it was seen to have an efficiency of 34.2%.
“The new cell is more efficient and has a simpler design that may be useful for a variety of new applications, such as very restricted area applications or low-radiation space applications,” said lead researcher Myles Steiner, researcher principal at NREL’s High -Crystalline Photovoltaic Efficiency Group in a first TechXplore report.
The secret ingredient
The new solar cell is built on an architecture known as inverted metamorphic multijunction (IMM) cells. The cell has three components that generate electrical current in response to light.
It is important to note that each of these junctions is made of a different material: gallium-indium phosphide at the top, gallium arsenide in the middle, and gallium-indium arsenide at the bottom. As these materials specialize in various wavelengths of light, this allows the cell to pick up more energy from across the light spectrum.
In addition, the researchers used “quantum wells” in the middle layer, which allowed them to achieve the new efficiency record. When the researchers sandwiched a conductive layer between two other materials with a wider band gap, they were able to confine the electrons to two dimensions, allowing the material to pick up more light back.
The middle layer of this solar cell includes up to 300 quantum wells, which greatly increases the total efficiency, according to a report by New Atlas. However, it should be noted that the production of this type of cell is expensive, which is already plaguing the renewable energy industry. Before the new cell can become widespread, researchers will need to cut expenses and find new potential uses.