A research team at Rensselaer Polytechnic Institute (Troy, New York, USA) has discovered that lead-free chalcogenide perovskite—a new material that hadn’t previously been considered for use in solar cells—could provide a safer and more effective option for solar energy storage and energy conversion.
The Rensselaer research team consisting of engineers, material scientists, and physicists published its study on lead-free chalcogenide perovskite in the current issue of Advanced Functional Materials. Notable members of the Rensselaer team include Nikhil Koratkar, who also served as the corresponding author of the paper, and Tushar Gupta, a doctoral student in mechanical engineering.
Organic-inorganic halide perovskites, which are a type of crystalline mineral, has shown promise as a key component in solar cells due to its ability to convert solar energy into power and its inexpensiveness relative to traditional silicon-based options. However, they also pose significant challenges: they are unstable when exposed to moisture and sunlight, decrease in efficiency as they degrade, and break down into hazardous lead and lead iodide.
“These types of materials give you very good performance on day one, but inside three or four days, maximum a week, you find that their performance drops precipitously,” says Koratkar, who also serves as an endowed professor of mechanical, aerospace, and nuclear engineering at Rensselaer. “Besides, these materials are not environmentally friendly since they contain lead.”
The Rensselaer research team overcame this challenge by demonstrating how a thin film of lead-free chalcogenide perovskite—barium zirconium sulfide (BaZrS3), to be specific—could not potentially replace lead-containing perovskite, but also serve as a safer, more stable application. The team tested the compound’s ability convert light into electrical current by using BaZrS3 to build a light sensor. Through theoretical calculations and computational modeling, they found that BaZrS3 is intrinsically more stable and highly resistant to both moisture and intense sunlight.
These results were validated through detailed device-aging studied conducted over a four-week period, Koratkar claims. What’s more, he was able to secure funding from the National Science Foundation to further develop and optimize these materials.
“The National Academy of Engineering has defined 14 grand challenges; one of those is to make harvesting energy from the sun cheaper and more widespread,” says Koratkar. “That’s the motivation of this work, to come up with new materials that could rival the efficiency of silicon, but bring down the cost of manufacturing solar cells, and that is the key to achieving this goal.”
Source: Rensselaer Polytechnic Institute, www.rpi.edu.