University of Missouri scientists are unlocking the secrets of halide perovskites — a material that's poised to reshape our future by bringing us closer to a new age of energy-efficient optoelectronics.
Suchi Guha and Gavin King, two physics professors in Mizzou's College of Arts and Science, are studying the material at the nanoscale: a place where objects are invisible to the naked eye. At this level, the extraordinary properties of halide perovskites come to life, thanks to the material's unique structure of ultra-thin crystals — making it astonishingly efficient at converting sunlight into energy.
Think solar panels that are not only more affordable but also far more effective at powering homes. Or LED lights that burn brighter and last longer while consuming less energy.
"Halide perovskites are being hailed as the semiconductors of the 21st century," said Guha, who specializes in solid-state physics. "Over the past six years, my lab has concentrated on optimizing these materials as a sustainable source for the next generation of optoelectronic devices."
To create the material, the scientists used a method called chemical vapor deposition. It was developed and optimized by Randy Burns, one of Guha's former graduate students, in collaboration with Chris Arendse from the University of the Western Cape in South Africa. And because it's scalable, it can easily be used to mass produce solar cells.
Guha's team explored the fundamental optical properties of halide perovskites using ultrafast laser spectroscopy. To optimize the material for various electronic applications, the team turned to King.
King, who primarily works with organic materials, used a method called ice lithography, known for its ability to fabricate materials at the nanometer scale. Ice lithography requires cooling the material to cryogenic temperatures — typically below -150°C (-238°F). This ultra-cool method allowed the team to create distinct properties for the material using an electron beam.
He equates the method to using a "nanometer-scale chisel."
"By creating intricate patterns on these thin films, we can produce devices with distinct properties and functionalities," King, who specializes in biological physics, said. "These patterns are the equivalent to developing the base or foundational layer in optical electronics."
Finding success through collaboration
While Guha and King work in different areas of physics, they said this collaboration has benefited both them and their students.
"I find it exciting because, on my own, there are only so many things I can do, both experimentally and theoretically," Guha said. "But when you collaborate, you get the full picture and the chance to learn new things. For example, Gavin's lab works with biological materials, and by combining that with our work in solid-state physics, we're discovering new applications that we hadn't considered before."
King agrees.
"Everyone brings a unique perspective, which is what makes it work," King said. "If we were all trained the same way, we'd all think the same, and that wouldn't allow us to accomplish as much as we can here together."
Their work is an example of the innovative energy research at Mizzou that's powering the new Center for Energy Innovation.
" Carrier relaxation and exciton dynamics in chemical-vapor-deposited two-dimensional hybrid halide perovskites ," was published in the Journal of Materials Chemistry C. Co-authors are Mizzou researchers Dallar Babaian, Daniel Hill and Ping Yu.
" Stabilizing metal halide perovskite films via chemical vapor deposition and cryogenic electron beam patterning ," was published in Small, a nanoscience and nanotechnology journal. Co-authors are Burns, Dylan Chiaro and Harrison Davison from Mizzou and Arendse at the University of the Western Cape.
