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Squeezed perovskite layers show improved light-handling capabilities

Perovskite is a rising star in the field of materials science. The mineral is a cheaper, more efficient alternative to existing photovoltaic materials like silicon, a semiconductor used in solar cells. Now, new research has shown that applying pressure to the material can alter and fine-tune its structures—and thus properties—for a variety of applications.

Using the Canadian Light Source (CLS) at the University of Saskatchewan, a team of researchers observed in real time what happened when they "squeezed" a special type of perovskite between two diamonds. 2D hybrid perovskite is made up of alternating organic and inorganic layers. It's the interaction between these layers, says Dr. Yang Song, professor of chemistry at Western University, that determines how the material absorbs, emits, or controls light.

The research team found that applying pressure significantly increased the material's photoluminescence, making it brighter, which Song says hints at potential applications in LED lighting. The team also observed a continuous change in its color from green to yellow to red. "So you can tune the color." Being able to observe changes to the material as they happen using ultrabright synchrotron light was critical to their research, said Song.

One of the biggest changes in the material came when the researchers applied a very large amount of pressure to the perovskite: it started glowing differently, signaling that its ability to handle light had improved. They also found the material squished more in one direction than others and that its internal structure became less twisted. Most similar materials become more twisted when they're squeezed. The findings of the research, which also involved the Advanced Photon Source (APS) at Argonne National Laboratory in Chicago, were published recently in the journal .

Their study, says Song, demonstrates that perovskite's "optical and electronic properties can be tuned and optimized toward application in a wide variety of devices" like LEDs and photovoltaics.

Song says the knowledge gained at the CLS about how pressure changes the structure of perovskite provides a recipe "to help the chemist or materials scientist create materials that exhibit the desirable properties." It is, he said, information that will be key in the design of the next generation of perovskite for various uses.