A new solar cell developed at the University of California Los Angeles (UCLA) has reached 22.4 percent efficiency, more than doubling the previous record for a dual-layer perovskite and copper, indium, gallium and selenide (CIGS) cell. Making it as efficient as some of the most efficient silicon-based solar cells on the market.
The previous record for that type of solar cell was 10.9 percent and was set by IBM’s Thomas J. Watson Research Center in 2015. The new device is only about 2 millimeters thick uses an 18.7 efficient CIGS cell that’s 2 microns thick and a 1 micron thick perovskite solar cell that boosts its performance. The new device was built at the UCLA Samueli School of Engineering.
“With our tandem solar cell design, we’re drawing energy from two distinct parts of the solar spectrum over the same device area,” said Yang Yang, UCLA’s Carol and Lawrence E. Tannas Jr. Professor of Materials Science. “This increases the amount of energy generated from sunlight compared to the CIGS layer alone.”
While CIGS solar cells have been around for a while, perovskite crystals are among the most promising technologies to reduce the costs of solar power further. Researchers have been able to manipulate perovskites to make them more efficient at converting sunlight into electricity. By making a solar cell more efficient it can reduce the costs.
“Our technology boosted the existing CIGS solar cell performance by nearly 20 percent from its original performance,” Yang said. “That means a 20 percent reduction in energy costs.” The perovskite layer can be sprayed on inexpensively and easily with existing processes.
The university already is planning on pushing the efficiency of the device to roughly 30 percent, which will be the next goal at the university. Other researchers have even more ambitious targets for perovskite-based solar devices that are up to 44 percent efficient.
Each layer of solar cell absorbs a different spectrum of sunlight. As such they can both perform to their high capabilities without interrupting the others’ efficiency. The researchers also developed a nanoscale interface that allows the device to operate at a higher voltage, increasing the amount of power it can export.
The research was published in Science. Yang, who led the research, was coauthored by Qifeng Han, a visiting research associate in Yang’s laboratory, Yao-Tsung Hsieh and Lei Meng. Both recently earned doctorates at UCLA.Tweet