Engineers discover lead-free perovskite absorber for solar cells

The M-cube lab has been featured in a recent article at Phys.org.  Excerpts from the full article are provided below.

“To meet the ever-increasing demands, low-cost and more efficient alternatives to silicon-based —currently the most widely used technology—are desirable. In the past decade, lead-halide perovskites have surged as the most promising class of alternative materials; however, they are unstable. They contain lead, which is toxic and poses potential health and environmental hazards such as groundwater contamination . . .

Rohan Mishra, assistant professor of mechanical engineering & materials science in the McKelvey School of Engineering, led an interdisciplinary, international team that discovered the new semiconductor, made up of potassium, barium, tellurium, bismuth and oxygen (KBaTeBiO6). The lead-free double perovskite oxide was one of an initial 30,000 potential bismuth-based oxides. Of those 30,000, only about 25 were known compounds.

Using materials informatics and quantum mechanical calculations on one of the fastest supercomputers in the world, Arashdeep Singh Thind, a doctoral student in Mishra’s lab based at Oak Ridge National Laboratory, found KBaTeBiO6 to be the most promising out of the 30,000 potential oxides.

“We found that this looked to be the most stable compound and that it could be synthesized in the lab,” Mishra said. “More importantly, whereas most oxides tend to have a large band, we predicted the new compound to have a lower band gap, which is close to the halide perovskites, and to have reasonably good properties.”

Mishra discussed the possibility of synthesizing KBaTeBiO6 with Pratim Biswas, assistant vice chancellor, the Lucy & Stanley Lopata Professor and chair of the Department of Energy, Environmental & Chemical Engineering. Shalinee Kavadiya, then a McKelvey Engineering doctoral student and now a postdoctoral research associate at Arizona State University, got to work on perfecting the recipe . . .

Mishra said these are first-generation solar that need more fine tuning of the band gap, but it is a good first step toward nontoxic solar cells.