According
to Interesting
Engineering, researchers at the Gwangju Institute of
Science and Technology, led by Professor Hobeom Kim, developed a new passivation process that allows
formamidinium lead iodide perovskite solar cells to reach over 24% power conversion efficiency.
Before
moving on, we should briefly explain what a perovskite is. It's a crystalline structure that can be made up of different
materials. You can mix and match atoms and molecules depending on your
needs.
The name comes from the shape (similar to the mineral perovskite), not the
chemical composition. They've shown potential for high performance in the solar
power industry, but there have been multiple
hurdles,
including failed efforts to improve efficiency. That's where this development comes in.
The
passivation process is meant to reduce defects in the semiconductor material
and improve efficiency, and Professor Kim's team achieved this by introducing
hexagonal polytype perovskite into the process.
"A typical approach so far has been to introduce
an external chemical reagent to deal with the defect problem," Kim said. "However, bringing in
external reagents could directly impact the crystalline quality of the
perovskite during crystal growth, so our work does not rely on such stabilizers. Instead we employ a chemically identical
polytype of perovskite, 6H polytype containing a corner-sharing component that
effectively suppresses the formation of defects in perovskite."