Tandem Solar Cell Reaching Records For Efficiently Generating Power

Materials specialists from the UCLA Samueli School of Engineering have developed a highly efficient thin-film solar cell that produces more energy from sunlight than typical solar panels, thanks to its double-layer design.

The device is manufactured by spraying a thin layer of perovskite, a low-priced compound of lead and iodine that has been shown to be very efficient at catching energy from sunlight, onto a commercially available solar cell. The solar cell that constitutes the bottom layer of the device is fabricated of a composite of copper, indium, gallium, and selenide, or CIGS.

The team's new cell transforms 22.4 percent of the incoming energy from the sun, a record in power conversion efficiency for a perovskite-CIGS tandem solar cell. The performance was verified in independent tests at the U.S. Department of Energy's National Renewable Energy Laboratory. (The previous record, set in 2015 by a collection at IBM's Thomas J. Watson Research Center, was 10.9 percent.) The UCLA device's efficiency rate is comparable to that of the poly-silicon solar cells that currently control the photovoltaics market.

The Analysis Section

The analysis, which was published now in Science, was led by Yang Yang, UCLA's Carol and Lawrence E. Tannas Jr. Professor of Materials Science.

"With our tandem solar cell design, we're drawing power from two distinct parts of the solar spectrum over the same device area," Yang stated. "This increases the amount of energy produced from sunlight compared to the CIGS layer alone."

Yang added that the method of spraying on a layer of perovskite could be quickly and economically incorporated into existing solar-cell manufacturing processes.

The cell's CIGS base layer, which is approximately 2 microns (or two-thousandths of a millimeter) thick, absorbs sunlight and generates energy at a rate of 18.7 percent efficiency on its own, but adding the 1 micron-thick perovskite layer improves its elasticity, much like how adding a turbocharger to a car engine can improve its production. The two layers are joined by a nanoscale interface that the UCLA researchers produced; the interface helps give the device higher voltage, which increases the quantity of power it can export.

And the entire assembly sits on a glass substrate that's about 2 millimeters thick.

"Our technology boosted the existing CIGS solar cell performance by approximately 20 percent from its original performance," Yang stated. "That means a 20 percent reduction in energy prices."

He added that devices using the two-layer form could eventually approach 30 percent power conversion efficiency. That will be the investigation group's next goal.

The Study Of Solar Efficiency Was Noted

The study's lead authors are Qifeng Han, a visiting analysis associate in Yang's laboratory, and Yao-Tsung Hsieh and Lei Meng, who both recently obtained their doctorates at UCLA. The study's other authors are members of Yang's analysis group and researchers from Solar Frontier Corp.'s Atsugi Research Center in Japan.

The investigation was sponsored by the National Science Foundation and the Air Force Office of Scientific Research. Yang and his investigation group have been working on tandem solar cells for several years, and their accomplishments include producing direct tandem solar cells that could be used in windows.

If you are seeking great solar panels, regardless of efficiency, we can find any level you seek here at HahaSmart.  Contact us now for a great price on solar.  

HahaSmart News - Stay Informed
Solar Incentives - Check State Incentives
Expand Solar Knowledge - Learn More About Solar
Join HahaSmart Installer Platform - Become a HahaSmart Verified Installer