In a bid to improve the stability and efficiency of perovskite solar cells, a team of researchers from the University of Arizona has worked on a new printing process called restricted area printing by ink drawing, or RAPID.

The researchers noted that perovskites are not used more widely as the relatively new technology is still very unstable. The experts stressed that their innovation could overcome that instability.

Adam Printz, an Assistant Professor of chemical and environmental engineering at the University of Arizona, and his team comprising co-investigators Erin Ratcliff, an Associate Professor of chemical and environmental engineering at the varsity, and Neal Armstrong, Professor Emeritus of Chemistry and Biochemistry and Optical Sciences from the institute, received a three-year, $700,000 grant from the Department of Energy Solar Energy Technologies Office (SETO) for the project.

Printz was selected as a part of the SETO Fiscal Year 2020 Perovskite Funding Program. The initiative is looking at deploying affordable solar at a faster pace, achieving the United States’ clean energy goals, and generating domestic jobs.

Lab-made perovskites share the same crystalline structure of the mineral and possess photoconductivity properties and the ability to be made into inks, noted the researchers.

The latter property enables perovskites to be printed out onto flexible pieces of plastic – similar to the way newspapers are printed, the researchers pointed out. The experts stressed that this property could make it possible to print out highly efficient and ultra-thin solar cells that are thin enough to be rolled up.

Starting work on the perovskite printing process in late 2019, Printz and his team demonstrated how the mechanism works on a small scale with 3D-printed parts. This funding allows the team to create a more scalable version of the project.

To make perovskite materials, a thin layer of specialized ink is spread over a surface. Following this, the ink is heated to allow the perovskite crystalline structure to take shape. This printed film presents several tiny grains separated by boundary areas, noted the researchers. When placed under a high-powered microscope, it looks like dry, cracked mud, they added.

“These boundary areas can actually interact with moisture in the air and cause the perovskite to convert into a completely different material that does not absorb light – which makes for a terrible solar cell,” Printz said. “We want to minimize grain boundary surface area so that those reactions don’t happen, and the perovskite is more likely to stay perovskite,” Printz emphasized.

The function of RAPID is to minimize the boundary areas. Reduced boundary area allows increased stability and efficiency.

As part of their efforts, Printz and his team aim to reduce the grain boundaries on the perovskite solar cells by 90%. They also hope to improve the cells’ efficiency stability by 50%.

The researchers remain hopeful that with RAPID working at scale, the production of perovskites would be positively impacted, improving the stability of these low-cost and high-efficiency devices to a large extent.

The SETO has been supporting research focused on increasing the efficiency and lifespan of hybrid organic-inorganic perovskite solar cells. SETO aims to fast-track the commercialization of perovskite solar technologies to decrease manufacturing costs.  According to SETO, there has been rapid progress in the conversion efficiency of perovskite solar cells from about 3% in 2006 to over 25% today. While perovskite solar cells have become highly efficient in a very short time, several challenges remain before they can become a competitive commercial technology. Mercom has been consistently reporting on innovations and breakthroughs in improving perovskite technology.

Recently a team from Brown University said that they had developed a molecular glue that boosts the efficiency of perovskite solar cells. Researchers at the Gwangju Institute of Science and Technology, South Korea, established a new method to increase perovskite solar cells’ efficiency by utilizing ions.