The technologies in thin-film photovoltaics continue to nip at the heels of silicon solar as efficiency improvements continue. In the latest efficiency improvement for a technology called CIS (copper, indium selenium) Japan’s Solar Frontier has created a solar cell that converts 22.9 percent of the sun’s light into electricity.
The CIS technology is an interesting technology because it can be integrated into flexible materials unlike crystalline silicon solar technologies, which aren’t flexible. As such, CIS technology can be incorporated into things like backpacks or roll-up solar charging devices, whereas crystalline silicon technology can’t be used in such devices. That said, Solar Frontier does make solar panels used in larger applications like conventionally sized solar panels.
“By making use of its research and development results in company production sites, Solar Frontier will continue to deliver a high level of actual output volume and competitive power generation costs to all of its customers,” the company said in a statement about the achievement. “Solar Frontier will build on the results that it has had here as it pursues the potential of CIS thin-film solar panels and provide a cleaner, comfortable life for all.”
Solar Frontier’s latest effort was achieved on a device the size of a square centimeter. The new record is 0.3 percentage points higher than the previous record of 22.6 percent set by the Center for Solar Energy and Hydrogen Research Baden-Württemberg (ZSW) in February 2016. It’s also higher than the 22.1 percent efficiency level set by First Solar’s Cadmium Telluride (CdTe) thin-film research cells. The latest results were verified independently by the National Institute of Advanced Industrial Science and Technology (AIST).
It’s the second time recently that Solar Frontier broke significant boundaries for the technology. In 2015, it became the first CIS technology company to push beyond the 22 percent efficient boundary.
The new device was developed with the help of Japan’s National Research and Development Agency's New Energy and Industrial Technology Development Organization (NEDO). Solar Frontier said the new efficiency level was achieved with technological engineering including CIS absorber engineering and enhanced surface treatment of the absorber layer.
While it’s a move forward for the CIS technology, it still lags behind the efficiency levels of other solar technologies. Crystalline silicon solar technologies have reached efficiency levels of 26.6 percent efficiency and 27.6 percent efficiency under concentrated sunlight, according to the National Renewable Energy Laboratory (NREL). The most efficient solar cells at this point, however, are multi-junction devices which use multiple layers of expensive materials to absorb certain parts of the sun’s spectrum of light. As of late 2017 the highest efficiency on record for one of these devices is 46.0 percent—close to half the sun’s light.Tweet