Researchers at Colorado State University and the Institute of Technology Bombay have partnered to build a more efficient four-terminal tandem solar energy cell. The work was recently described in ACS Energy Letters and uses both perovskite and cadmium telluride materials together to reach an impressive 24.2% efficiency – a significant improvement over the previous high of 7%.
Material science researchers have been studying potential ways to use or combine the naturally occurring perovskite and cadmium telluride semiconductors to improve solar cell efficiency for years. That is because they are both cheap and highly effective semi-conductors. The pair also provide complimentary benefits as perovskite is a flexible and versatile material with tunable bandgap, while cadmium telluride has a proven commercial viability in converting the most optimal range of solar spectrum into electricity.
The new cell architecture described in the research paper is the first of its kind for this combination of semiconductors and layers the two materials on top of each other. In addition to improved efficiency, the approach is also likely to be cheaper to produce than the common silicon-based solar panels, among other benefits.
The work at CSU was led by Amit Haren Munshi, an assistant research professor in the Department of Mechanical Engineering. Munshi said the demonstration described in the paper sets a new benchmark for thin-film solar technology.
“While this is a great stride forward, the full potential of this solar cell architecture is still not yet realized,” he said. “We will be continuing our efforts to improve efficiency while also working on ways to commercialize this technology to get it out of the lab and into use as soon as possible.”
Improving the efficiency of solar panels and being able to produce them rapidly for use in a variety of environments remains a key goal in the fight against climate change. Current photovoltaics require a lot of resources, such as glass to be manufactured and space to operate in the field. Tandem cells like the one described in the paper could provide a strong potential solution to those barriers with further improvement overtime thanks to cheaper and faster manufacturing methods and higher efficiencies, even in lowlight conditions.
This work is partially funded by the National Science Foundation through their Industry-University Cooperative Research Centers Program. The two teams are also working on a joint patent filing with CSU STRATA as there is interest from the industry to commercialize this technology.
Munshi said that they would continue to test and refine their solar cells with a goal of reaching 27%-28% efficiency in the near future.
“As the world increasingly turns to renewable sources of energy, innovations like these are critical in the fight against climate change and in making sustainable electricity available to everyone – including remote regions that are still not connected to the electrical grid,” he said. “We are only getting started, and you can expect a lot more over the coming months and years.”
