Zhong Chengchao's website
Solid State Chemistry
Synthesis of undiscovered inorganic solid materials
and exploration of their functionality
In order to build a sustainable society, materials with new functional properties that solve resource, energy, and environmental problems were proferred. Inorganic solid materials exhibit a wide variety of properties (dielectricity, magnetism, optical properties, electrical conductivity, etc.) and have the potential to realize many new functions. These diverse properties are often due to the crystal and electronic structure of the material, so it is essential to understand the properties from a fundamental perspective. I aim to understand the properties of materials from a crystal structure perspective and, based on the knowledge gained, to create new materials and explore their functionality.
Previous study
@Kageyama Labortory Kyoto University
Design of novel fluoride ion conductors
Fluoride-ion batteries, which use fluoride ions (F−) as a carrier, are expected to have an energy density ( 5000 Wh L−1 ) that is more than twice that of commercially available lithium-ion batteries . However, F− conductor with high conductivity and a wide potential window at room temperature has not yet been found in the electrolyte.
By introducing different anions other than F− and cations with lone pairs into the crystal structure, I aim to broaden the scope of materials exploration, elucidate the conduction mechanism, and establish design guidelines for high-performance F− conductors.
J. Mater. Chem. A 2024 , 12, 14419-14425.
Chem. Mater. 2023 , 35 , 4235-4242.
Designing crystal structures and properties using lone pair electrons
Cations such as Pb2+ and Bi3+ have ns2 lone pairs that cause steric hindrance and are known as "chemical scissors" that change the crystal structure . I am involved in understanding and designing the structures and properties of materials that contain such unique cations.
For example, the new compound BiSF obtained by high-pressure synthesis has lone pairs that become activated during decompression, distorting the crystal structure (Chem. Mater. 2024, 36, 4495-4501.). The layered perovskite Bi4NbO8Br not only has large intralayer polarization ( 43.5 µC/cm2 ) caused by lone pairs, but also has interlayer polarization, which is unusual for layered perovskites (Inorg. Chem. 2022, 61, 9816-9822.) .
Chem. Mater. 2024 , 36, 4495-4501.
Inorg. Chem. 2022 , 61 , 9816-9822.
Development of novel layered oxyhalide photocatalysts
We have found that Bi4BaO6Cl2 , which combines a fluorite bilayer and a fluorite trilayer, and its Ca, Sr substituted analogue Bi4AO6Cl2 (A = Ba, Ca, Sr) function as promising photocatalysts for water splitting. The band structure of Bi4BaO6Cl2 obtained by DFT calculations suggests that photoexcited electrons and holes are transported separately through the fluorite bilayer and fluorite trilayer, revealing the possibility of a new photocatalyst that controls the conduction of photoexcited carriers by combining different layers .
Inorg. Chem. 2021 , 60 , 15667-15674.
Searching for correlation between polar structure and photoexcited carriers
It has been proposed that the polarization in polar structures separates photoexcited electrons and holes in opposite directions and suppresses carrier recombination, but there is still a lack of experimental evidence to explain the dynamics of photoexcited carriers in crystals.
We discovered complex nanoscale domain structures (regions with constant polarization) in single crystals of Bi4NbO8X (X = Cl, Br) and explored their correlation with photoexcited carriers.
Inorganics , 2018 , 6 , 41.
Appl. Phys. Express , 2020 , 13 , 091004.