Ascent Solar gains funds from Air Force for thin film tandem PVs
San Jose, CA, October 4, 2007
Source: EE Times
http://www.eetimes.com/news/semi/showArticle.jhtml?articleID=202201012
Ascent Solar Technologies Inc., a developer of thin-film photovoltaic materials, has obtained more funding from the U.S. Air Force Research Laboratory (AFRL). The goal is to increase the funding of Ascent Solar’s development of thin-film tandem photovoltaics (PV), based on monolithically integrated CIGS technology. The contract modification represents up to $749,000 of additional contract value over a 27-month period.
The three most common thin-film technologies are amorphous silicon (a-Si), cadmium telluride (CdTe) and copper-indium-gallium-diselenide (CIGS). CIGS currently has demonstrated the highest laboratory efficiency at 19.5 percent, according to the Littleton, Colo.-based company. Since 1995, AFRL has provided funding for the development of the flexible CIGS at ITN Energy Systems Inc. and now at Ascent Solar, including the development of aspects of future tandem devices.
”Tandem solar cells are two solar cells in a stack, where the top cell collects the blue portion of the solar spectrum and the bottom cell collects the rest of the visible spectrum,” according to Ascent. ”It is believed that the type of technology pursued by this AFRL program has the potential to reach an efficiency of 20 percent in the future.”
“While our baseline CIGS that utilizes a single junction to convert the sun’s energy has been performing very well, we are always striving to increase cell performance that can potentially lead to further reductions in system-level costs to the end user,” Ascent Solar Chief Technical Officer Joseph Armstrong said in a statement.
”Efficient conversion of the sun’s energy is very critical to space and near-space applications, as higher efficiencies correlate directly to smaller, lighter-weight solar arrays, and significantly lower launch cost,” he said. ”Likewise, in terrestrial and building integrated photovoltaic (BIPV) applications, such as roofing tiles and building facades that operate at elevated temperatures, future tandem devices can provide a significant advantage over existing thin film by delivering more power in less area.”