Halide perovskites are semiconductors with a crystal structure in a framework of octahedrons, the cavities of which are filled with inorganic cations or small organic cation molecules. Scientists use the perovskite lattice to create perovskite-like crystals in which octahedrons can be connected via apexes, edges or faces. To achieve this, synthesis is performed using large organic cations with unusual patterns, which give these compounds new quantum mechanical properties.
The researchers from SPbU have synthesized a new perovskite-like compound with the chemical formula (3-CF3pyH)2(3-CF3py)Pb3I8, which has a rare honeycomb structure dubbed “kagome” after the traditional Japanese pattern used in bamboo basket weaving. The honeycomb channels of this compound are filled alternately with neutral molecules of 3-fluoromethylpyridine and corresponding organic cations.
“In the course of studying this quaint structure, we realized that the material under study does not glow at room temperature, but it does have an intense glow with a wide spectrum at the temperature of liquid nitrogen (−196°C),” Anna Samsonova, research engineer at the Laboratory for Crystal Photonics, is quoted as saying by SPbU.
The researchers at the UoC simulated the electronic properties of the honeycombs: electronic band structure calculations showed the presence of topological states close to the conduction band (kagome zones). The presence of these zones surprised the scientists, as the compound is made of non-metallic and non-magnetic materials. “We hope that future experiments with external impact will prove our hypothesis that (3-CF3pyH)2(3-CF3py)Pb3I8 is a high-potential quantum material,” UoC professor Constantinos C. Stoumpos is quoted as saying by SPbU.
This solution could find application in photonic and optoelectronic devices running the gamut from lasers to solar batteries.
