Connor Bischak, left, and Perry Martin in the Bischak Lab. Photo credit: Todd Anderson.
In today’s energy-intensive environment, designing new devices for more efficient and renewable energy sources is at the forefront of scientific research. A particularly interesting approach utilizes Ruddlesden-Popper perovskites—a type of layered material made from alternating sheets of inorganic and organic components.
These materials are potentially ideal for several applications, including light-emitting diodes (LEDs), thermal energy storage and solar-panel technology.
Recent research led by University of Utah graduate student Perry Martin in the Bischak Lab, housed in the Department of Chemistry, utilized temperature-dependent absorption and emission spectroscopy, as well as X-ray diffraction, to study the phase transition behaviors of perovskites. A phase transition is a discrete change from one state of matter to another (such as ice to liquid water). Some substances, including water and perovskites, have multiple solid states with different properties.
The Bischak Lab demonstrated a connection between phase transitions and the material’s emissive properties. This introduces a form of dynamic control, or tunability, that offers multiple benefits for technological applications. Specifically, because perovskites contain both organic and inorganic components, the organic layers undergo phase transitions that influence the structure of the inorganic layers. The interplay of the organic and inorganic layers drastically alters the material’s properties.
“There are these almost greasy chains that kind of crystallize together. When you hit a certain temperature, those will essentially melt and become more disordered,” said Assistant Professor Connor Bischak, senior author on the new study. “The melting process influences the structure of the inorganic component, which controls how much light is emitted from the material and its wavelength.”