American scientists break a new record for solar cell efficiency

Recently, researchers at the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) have developed a solar cell that achieves a record efficiency of 39.5% under 1 sun's global lighting unit, breaking the world record for solar cell efficiency. , the results have been published in the journal "Joule".

According to the press release, the conversion was done under solar-comparable light conditions. Although the previous record for the efficiency of the experimental solar cell was 47.1%, it must be emphasized that this record was achieved under extremely concentrated light. The 39.5% efficiency record created this time was created under 1 solar global lighting unit.

"The new cells are more efficient and simpler to design, and can be used in a variety of applications, such as environments where light is highly constrained," said NREL principal investigator and senior scientist Myles Steiner.

This new type of solar cell is built on an architecture called an inverted metamorphic multijunction (IMM) cell. It has three components that generate electrical current in response to light. Importantly, each of these junctions is made of a different material: Gallium Indium Phosphide at the top, Gallium Arsenide at the center, and Gallium Indium Arsenide at the bottom. They are able to absorb a variety of wavelengths, so the battery can capture more energy from the entire spectrum.

In addition, the researchers used "quantum wells" in the interlayer, which allowed them to achieve record conversion efficiencies. When the researchers sandwiched the conducting layer between two other materials with wider band gaps, they were able to confine the electrons in two dimensions, allowing the material to capture more light in return.

According to a report by New Atlas, the interlayer of such solar cells contains as many as 300 quantum wells, which greatly improves the overall efficiency. However, it should be noted that producing this type of battery is still expensive, which has plagued the renewable energy industry for quite some time. Before this new type of battery can become widespread, researchers need to reduce costs and find potential new uses.